What men are poets who can speak of
Jupiter as if he were a man, but if he is an immense spinning sphere of
methane and ammonia must be silent ?
I regularly visit NASA's picture of the day; I've also trawled
the archive collecting links to nice
pictures and classifying them in a manner of my chosing. What a remarkable
universe we inhabit !
The distance light travels in a year is called a light year and its
standard abbreviation is ly; applying standard SI quantifiers, we get k ly for
a thousand light years, M ly for a million, G ly for a milliard of them and so
on. One millionth of a light year, a µly, is 9.46 million kilometres
(5.88 million miles). Light from the Sun takes 8.28 minutes (15.74 millionths
of a year) to reach the Earth.
The headings of some nested portions of the following list provide
to searches in the
archive. This page comes with two style-sheets: a plain one and one
which folds away the parts you're not looking at – if your
browser supports suitable style features, of course. The folding version
(which takes some getting used to, but saves a lot of paging up and down; and
provides a hierarchic approach to finding things) depends on hover, which
might only work with a mouse; and only works if your browser considers all
ancestors of any hovered element to be hovered (it is not clear to me whether
the standards specify that).
Images of the whole sky, from one end of the spectrum to the other.
From inflation to WMAP A pictorial history of time.
Aminated γ-Ray Sky simulation
Fermi's first light Full sky in γ-rays, from a new space telescope launched 2008 June
11. Four days of observation, with plenty more to come.
Full sky showing γ-ray pulsars Including 16 new pulsars, discovered by Fermi.
Fermi's first three months
Fermi's source catalog after 11 months
Milky Way γ-bubbles After two years, Fermi had accumulated enough data to reveal a
Hot Gas Filaments Chandra's X-ray view of normal matter as filaments throughout the universe.
X-Ray Sky ROSAT Explores The X-Ray Sky
All-Sky Panorama 51 wide-angle photograph mosaic in visible light; and the same
later update using digital images. Each
is aligned so that the Milky Way runs along the centre.
2 micron sky The 2MASS Galaxy Sky – the whole sky at two
also available with
distance encoded by colour.
Planck's microwave view
Background anisotropy Wilkinson Microwave Anisotropy Probe data on the microwave background's
variations. Includes an anomalous
Cosmic Background 22 to 90 GHz, with galactic foreground and the Doppler yin-yang (below)
Doppler dipole dominates variation in the cosmic microwave background.
Infrared Sky COBE's DIRBE instrument; sky at 3.5 microns. Cool stars in our galaxy
and dust in the solar system are prominent.
Far Infrared Sky
Our Dusty Universe COBE's picture of the dusty background (far IR)
Radio Sky @408MHz
Radio Hydrogen A Sky Full Of (atomic) Hydrogen, seen in the (21cm, 1.42GHz) radio
emissions from flipping the electron and proton spins between opposite and
If you stare into an apparently empty bit of sky for long enough, you'll see
stars; they're just further away than the others.
Hubble Ultra Deep Field Includes link to HDF, which links to HDF South. Later
in near infra-red to catch ancient
galaxies with red-shifts likely around 8.
Chandra Deep Field Hubble's Deep Field South in X-rays
Hubble Deep Field A ten-day exposure of a dark corner of Ursa Major
Hubble Deep South A Deep Field In The Southern Sky
IR HDF The Hubble Deep Field in infra-red
Spitzer's deep background Showing a diffuse IR glow suspected of coming from the first generation
of stars, 13ish G yr ago and hundreds of times as massive as our Sun.
NTT SUSI Deep Field
Galaxy @ z=4.92 Behind CL1358+62: A New Farthest Object
GRBs and Quasars
or gamma-ray bursts and quasi-stellar objects, to give them their proper
names. Distant things of extreme brightness, implying spectacularly energetic
sources. GRBs have proven so elusive that a dedicated satellite, Swift, if
constantly on the look out for them, to alert other telescopes to look at their
sources before they can fade back into obscurity.
Galaxy-powered cannon Quasar 3C175 emits relativistic jets of particles
spat ? Did galaxy NGC 4319 eject Quasar Markarian 205 at high speed ? Or
are they merely randomly juxtaposed on our view of the sky ?
6 Portraits A Quasar Portrait Gallery
Micro-Quasar Puffs GRS1915 is a small black hole on the far side of our Galaxy; here seen
expelling gas jets at .9 c
GRB080319B in X and UV The most distant thing ever seen by the naked eye, 7.5 G ly away.
Dancing black holes As two galaxies merge, their super-massive central black holes orbit
one another, 25 k ly apart, while moving at c/250 relative to their
GRB090423, .63 Gyr after the Big Bang, z = 8.2 Hanny's Voorwerp IC2497's
extra-galactic glowy blob shines in Oxygen-ion green, probably due to light
emitted by a quasar that's now shut down.
GRB110328A, z = 0.351
Groups, clusters and collisions.
Bulls Eye Einstein Ring
Cluster acting as a lens
The Sloan Great Wall … and other structures on a scale that dwarfs superclusters
– clusters of clusters of galaxies.
The Bird A collision of three galaxies, with relative speeds up to 0.4 Mm/s
ACO 3627, near the center of the Great
Attractor Close neighbours and the mess between them
Galaxies tend to keep one another company.
One behind the other NGC 3314:
When Galaxies Overlap
Spiral and Ellipse c. .35 G ly away
The dance of M81 and M82
spiral and an ellipse; the latter is also known
as the cigar galaxy. Each is stirred up by the
tidal stresses of their mutual orbit, about 12 M ly
away in Ursa Major.
Intergalactic dust lane NGC 1410/1409: Intergalactic Pipeline, 300 M ly away, 20 k ly apart
NGC 5905 and 5908 Two spiral neighbours, one face-on, the other edge-on
The Leo Triplet Groups and clusters
When they get crowded, things can get quite intense. Clusters tend to
comprise tens or hundreds of galaxies; groups are smaller. On a truly cosmic
scale, clusters can band together to form superclusters. When many galaxies
hang around close together, the intergalactic gas is apt to contribute
significantly to the total mass (of normal matter – dwarfed by the
accompanying dark matter) and is often hot enough to emit X-rays.
Four of Stephan's Quintet
Abell S0740 0.45 G ly away and most of a M ly across
Pandora's cluster Abell 2744, with its misaligned dark matter and X-ray-emitting gases.
Markarian's chain Several galaxies moving together, and
more imaged near them, within the Virgo cluster
which, being only about 48 M ly away, is the nearest cluster to (and has a
definite gravitational effect on)
group; there are over 2000 galaxies in the cluster, which spans about 10
degrees on Earth's sky, so it's 8 to 12 M ly across.
The bullet cluster Showing separation between its (non-dark and dark) matter
MACSJ0025: cluster collision 6 G ly away in Cetus, two large clusters, spanning about 3 M ly, are
colliding – and their dark matter gets dislocated from the normal
The Hercules Cluster a.k.a. Abell 2151, likely similar to some of the universe's earliest
JKCS041: ancient cluster At a red-shift of 1.9, the earliest cluster yet identified, c. 10 G yr ago.
NGC 7769–7771 A stately dance of merger, spanning hundreds of mega-years.
The trouble with Abell 1689
Hickson's compact groups
Paul Hickson and
colleagues catalogued compact groups of galaxies, often in the process of
merging. They can be dramatic or, like clouds, suggest the shapes of more
HCG 90: a motor-bike !
Hickson Compact Group 87 – two
spirals and at least one elliptical – with a spiral in their
HCG 44 a.k.a. NGC 3190; several spirals and an ellipse, 60 M ly away,
Perseus Cluster Dominated by central NGC 1275 (a.k.a. Perseus A; over 100 k ly across,
so only slightly wider than our galaxy, but rather more massive), the Perseus
cluster is roughly a quarter G ly away.
Many galaxies … and
a wider field view of roughly
the same portion of the centre of the Perseus cluster.
X-Ray Skull The Perseus Cluster's X Ray Skull; image of intracluster gas, more
massive than all the cluster's galaxies.
Ribbons of Perseus Unusual gas filaments surround NGC 1275, shown here in pink.
X-Ray: Perseus cluster core 250 M ly away; a very dangerous place to be
Hubble's visible NGC 1275 … combined, when hovered, with Chandra's X-ray and radio from
the Very Large Array.
When galaxies collide, the stars miss one another but the interstellar gas and
dust clouds get pummelled into bouts of star-forming. Violent prettiness
NGC 4676, The Mice
Long tails resembling warring jelly-fish
or a celestial acrobat with feet gripping a
trapeze at the top of a swing.
The Antennae collision The
galactic fire-ball in the middle also
looks impressive in near infrared
NGC 4038 and NGC 4039; c. 60 M ly away
towards Corvus, the tails span c. 0.5 M ly.
NGC 3256: mid-collision Two galaxies appearing to be one, as they pass through one another; 0.1
M ly across, 100 M ly away in the Hydra-Centaurus supercluster.
Spiral Galaxy NGC 3310
Whirlpool Pair Spiral M51 (NGC 5194) and blob NGC 5195.
Sharper Whirlpool Pair High resolution image of M51 from Hubble's ACS.
Arp 188: Tadpole's Tidal Tail
Arp 271: Colliding spirals
Arp 272: collision in progress a.k.a. NGC 6050, IC 1179, 450 M ly away in the Hercules cluster.
Arp 273: a pretty pair
Arp 274: another nice pair, with decorations
Arp 295: linked galaxies Linked by a trail of stars and debris 250 k ly long; 270 M ly away
Stretched giant NGC 6872 Later viewed
in colour. Over 400 k ly
across and about 200 M ly away.
Fornax A's Radio Lobes The Giant Radio Lobes of Fornax A – NGC 1316's jets, spanning 100 M ly.
Arp 230: United spirals? Apparently one galaxy, suspected of being the result of two that collided
NGC 520 a.k.a. Arp 157; 100 M ly away, 100 k ly across.
Arp 147's pair of rings
NGC 2623 (a.k.a. Arp 243) Spans 50 k ly, is 250 M ly away.
Supermassive black holes formed in galactic
Keenan's pair, Arp 104 NGC 5216 and NGC 5218, linked by a
string of debris 22 k ly
ARP 286: Virgo triplet
ARP 273 (a.k.a. UGC 1810)
Ripples in NGC 474's smooothness
Individual island universes: jewels nestling deep in the velvet blackness of
Cartwheel Residue of a collision, with star-formation wave-front expanded out to
its edge; diameter is 0.1 M ly and it's about 0.4 G ly away.
Marble Unusual giant galaxy
NGC 1316 –
elliptical, but with dust lanes and a disk, suspected remants of a spiral that
collided with it.
X-Ray Cygnus A Galaxy belting out jets
Hoag's Strange Ring
Elegant Ring AM 0644-741 300 M ly away, 150 k ly across; ripple of star-formation caused by
Alchymic whirlpool fumes NGC 4388 Expels Huge Gas Cloud
Helix galaxy NGC 2685 / Arp 336: polar ring galaxy; disk galaxy except for the bits
in orbit in a perpendicular plane. 50 k ly across, 40 M ly away, in Ursa
Black hole power NGC 4696, a large globular galaxy (150 M ly away) with a super-massive
black hole in it, generating huge amounts of energy which the galaxy radiates
in X and radio.
Starburst galaxy M94 / NGC 4736: contrasting
a spiral in red and UV.
Circinus Colourful whirl-pool; technically a spiral, but not in the classic
NGC 660: Polar Ring A
orbited by rings perpendicular to its
Polar Ring NGC 4650A
I Zwicky 18 59 M ly away and initially mistaken for a very young galaxy.
Edge-on thin lenticular NGC 4452
galaxies Some galaxies are just a mess.
Starburst NGC 1313 Only 15 M ly away,
almost spiral, but
distincly messed up – yet with no evident neighbour to mess it up.
Irregular NGC 55 Believed to be an analogue of our neighbour, the large Magellanic
seen edge-on, instead of face-on.
NGC 4449: small and irregular Similar to the Large Magellanic Cloud; 12 k ly across, 20 M ly away in
Nearby starburst dwarf NGC 1569 Only 11 M ly away (practicaly in the Local Group) and about 8 k ly
across, an irregular dwarf undergoing a burst of star formation.
Centaurus A A globular galaxy (60 k ly across, 10 or 13 M ly away) with an
anomalous centre, about 1 k ly across, suspected of being the remains of a
spiral galaxy swallowed up about 0.1 G yr ago.
Rippling outer shells
Dusty heart Center: natural colour, showing dust clutter well
Color and Mystery (X-ray)
Galaxy inside Spitzer image, in infra-red.
Across the spectrum A composite of radio, visible and X-ray, showing a 13 k ly jet of
coming away from a black hole in its
The elegant class of peers of our own Milky Way; galaxies in which most of the
stars lie in a disk and circulate in a common sense around its centre
(although, in some cases, there are two populations of stars, circulating in
opposite senses); they are usually dominated by dark dust lanes and a
few arms, in the form of equiangular
spirals. If they sometimes look like a pool
of water swirling round on its way to go down a plug-hole in the middle,
that's because the black hole in the middle is indeed a kind of cosmic
M101 in UV A giant spiral galaxy, seen by the light of its hottest stars.
The classic view.
M74: Perfect Spiral
Archetype of the spiral
M77 (NGC 1068) and its outskirts
NGC 1309 and Friends
M74 with ULXs Ultra-luminous X-ray sources – 1e4 Sun.mass black holes –
and a pretty face-on spiral.
UV Ring in NGC 6782 Barred spiral, 80 k ly across, 180 M ly away towards Pavo
Starburst M94, in Canes Venatici 39 k ly across, c. 15 M ly away in the Canes I group; turns out to
faint outer spiral arms.
Barred spiral M95 A bright and shiny Catherine-wheel
Fried egg NGC 7742, a Seyfert spiral; has highly active (and variable) central
Panchromatic From IR to UV; NGC 1512.
M63: Sunflower (a.k.a. NGC 5055)
The Whirlpool, M51
Host of supernovae in 1994,
2005 and 2011.
M51/NGC 5194 in Dust and Stars, combining
images from Kitt Peak and Hubble.
Whirlpool's dust in infra-red
M51 highlighting Hydrogen
Gangly NGC 3184 face on, with plenty of blue sparkles in its arms
Wispy Pinwheel M101:
The Pinwheel Galaxy. 25 M ly away,
c. 170 k ly across.
Spitzer: M101 in infra-red
M101 in colour
M83's dynamic centre
NGC 2997 Early image from Antu, the first of the four Very Large Telescopes of
the European Southern Observatory, in Chile.
M61 in Virgo a.k.a. NGC 4303, discovered in 1779
NGC 4314's halo NGC 4314: A Nuclear Starburst Ring – old galaxy with new ring
of purple shiny stars and an inner micro-galaxy.
One Armed NGC 4725 Infrared, 41 M ly away, .1 M ly across;
NGC 6217 and its prominent central bar
NGC 4911 falling into the Coma cluster
NGC 5584 and its Cepheid variables Slanted
Naturally, very few galaxies are exactly edge-on or face-on; but many are close
enough to one or the other for a rough, if somewhat arbitrary, classification.
The rest fall in between.
Distant NGC 4603 Used in HST study of Hubble's constant and the Expanding Universe.
Exquisite NGC 7331 …
along with background galaxies.
NGC 1350 Pearly blue blob; 85 M ly away towards Fornax, 0.13 M ly across.
NGC 1365 0.2 M ly across, 60 M ly away;
member of the Fornax cluster
View through M96 … a dominant member of the Leo I galaxy group, with a more
distant edge-on spiral visible through its outer spiral arm.
Distorted NGC 2442 in Volans
Normal Spiral NGC 300. Very pretty, and studied in great detail.
NGC 3370 Sharp view from Hubble ACS
Dusty NGC 7049
M65 in the Leo Triplet
M66 in the Leo Triplet
M66 with its faint extensions NGC 2841 …
a close-up of its centre. It's 64 Mly away
and about 150 kly across.
Blotchy NGC 3521, also in Leo
Mottled NGC 2903
M64: the black eye 17 M ly away, 80 k ly across, with a central part 6 k ly across
rotating in the opposite sense to the outer parts.
Arp 77 and its satellite A spiral, a.k.a.
NGC 1097, with long arms
tangling with a satellite about 43 k ly from the spiral's centre. NGC 1097 is
a Seyfert galaxy, 45 M ly away in Fornax, and turns
out to be emitting mysterious jets.
One-armed Arp 78 (NGC 772)
M106 in Canes Venatici Seyfert active galaxy, a.k.a.
NGC 4258, 30
k ly across, 21 M ly away, in the constellation of Hunting Dogs.
Deep view of M106
M106's extra arms, in X-ray and radio
NGC 613 from Paranal 65 M ly away, 0.1 M ly across, with a bar and rather more arms than
usual; in Sculptor.
NGC 3621: 22 M ly away
NGC 4651, with its umbrella
a.k.a. NGC 3031 It's 11.8 M ly away, 70 k ly across and the principle member of a small
group (comparable to
group). Its dance
with the cigar galaxy, eliptical M82, shall doubtless end in a union. Our
view of it is partially obscured by barely visible dust clouds just outside our
own galaxy, the integrated flux nebula (named after the subtle technique needed
to observe it), but individual stars are discernible.
Through the integrated flux nebula
Hubble resolves individual stars
Across the spectrum From IR to X-ray, highlighting its voracious black holes.
Hot young stars in UV Showing its satellite, Holmberg IX.
Arp's loop Initially thought to be a stream of debris from M81's interaction
with neighbours, this patch of light turns out to be part of the fore-ground,
close to our own galaxy, coincidentally superimposed on M81.
The view that best exposes (often photogenic) dust-lanes.
NGC 5866 60 k ly across, 44 M ly away towards Draco and lenticular
Supernova beside Spiral Rumors of a Strange Universe
NGC 1531–1532, on the banks of
NGC 3628 in the Leo
triplet (which also includes spirals M66 and M65)
NGC 4013 and its tidal tail
Knife-edge or splinter: NGC 5907
NGC 4565, in Coma Berenices, only 40 M ly
away, .1 M ly diameter and similar to the Milky
NGC 4631: the Whale
Bubbling Cauldron NGC 3079, expelling pillars of dust from its centre at c/180 or so.
Warped ESO 510-13
ESO 510-13 in context
NGC 253: dusty star-burst
Hubble's ACS's close-up of NGC 253 – and a later
composite with better
NGC 253 in fine detail Also known as the silver dollar galaxy or (after the constellation
it's in, and the eponymous group, of which it's the largest member) Sculptor
NGC 891 sideways
NGC 891 showing dust kicked up by
NGC 4216 and the remnants of its recent
Galaxy, M104. One of the finest examples of an edge-on spiral, with a dusty rim; 28
M ly away, at the southern edge of the Virgo Cluster.
Across the spectrum
Our Milky Way Galaxy has a few travelling companions: one larger spiral galaxy,
Andromeda, and an assortment of about 30 smaller galaxies out to about 10 M ly
Antlia A dwarf spheroidal galaxy with only about a million stars.
NGC 404: Mirach's Ghost Almost drowned out by a foreground star's brightness, it's 10 M ly away
and I'm not sure whether it's counted in the Local Group.
NGC 2366 nurseries Bright stars, dim galaxy – a small irregular galaxy, scarcely
more than a pair of star-forming clusters; but mighty powerful with it; 10 M
Sextans A A seemingly square galaxy; small dwarf irregular, 5 k ly across, 10 M
The Aquarius Dwarf 3 M ly away in the local group
Leo A Dwarf Irregular, 10 k ly across, 2.5 M ly away towards Leo.
Barnard's NGC 6822 A dwarf irregular galaxy, roughly rectangular, with many emission
nebulae; a.k.a. Barnard's Galaxy; 1.5 M ly away, towards Sagittarius.
IC 10: starburst dwarf 2.3 M ly away and only 5 k ly across; in Cassiopeia, view obscured by our
Galaxies move slowly, so it can be hard to work out whether one is
gravitationally bound to another. But it looks like Andromeda has a few
Dwarf elliptical M32
Elliptical M110 15 k ly across; has young stars and dust clouds, atypically for
Dwarf elliptical NGC 205, a.k.a. M110
Central M33 in HII Also available
in combination with
broad-band filters or in visible light.
Sparse spiral M33 in O and H Also known as
triangulum (and pinwheel,
for bonus confusion with M101); may be orbiting Andromeda (M31). Over 50 k ly
across, the third largest member of the local
group (a quarter of the size of the first two) is about 3 M ly away.
Pegasus Small dwarf spheroidal, probably orbits M31; c. 2 k ly across.
M31: the even bigger member of our local group, 2.5 M ly away, with over twice
the diameter of the Milky Way and a million million stars, compared to 0.4
times that for the Milky Way.
Edwin Hubble's proof of Andromeda's distance
Infra-red from Spitzer
Infra-red from WISE
With Hale-Bopp The Comet and the Galaxy
With Ikeya-Zhang Comet + Galaxy
Compared to Selene Infra-red and X-ray Showing the
material of which future stars shall be made and the carcasses of old
Satellites of the Milky Way
Counting only the galaxies: the galactic halo is also home to about 150
Canis Major Dwarf Closest of the dwarfs being swallowed up by the Milky Way; only 42 k
ly from the Galactic center, and so spread out it's more a stream of debris
than a galaxy.
Sagittarius Dwarf Our 2nd closest neighbour, an ancient irregular galaxy.
SagDIG Tidal Stream An artist's depiction of the stream of detritus around our galaxy,
left as it tears apart the Sagittarius Dwarf.
Magellan's clouds LMC; next day SMC.
LMC deep field
LMC in H-α
LMC gas profile in HSO
LMC close-up Stellar Laboratories in
UV SMC from UIT
SMC and 47 Tucanae
The Magellanic Stream
Leo I A young dwarf spheroidal galaxy, only just orbiting the Milky Way,
about a quarter M pc (.8 M ly) away.
Other nearby galaxies
Not quite close enough to be gravigationally bound to the group, some galaxies
are, none the less, close enough to interact with it. Parenthetical distances
here are how far away each is. See
also: M81, Centaurus
IC 342 not quite hidden (7 M ly) … behind the Milky Way; and a more recent,
clearer picture from Kitt Peak.
IC 342 through the Milky Way (7 M ly)
NGC 6946 (10 M ly)
Also known as
the Fireworks Galaxy.
Spiral NGC 2403 from Subaru (10 M ly) Just outside
group; has open clusters, dust lanes, a tight nucleus and
some cute blobbiness.
Southern Pinwheel (12 M ly) M83, a.k.a.
the thousand-ruby galaxy, the
closest of a group of galaxies, around 15 M ly away, that includes
Centaurus A and NGC 5253.
Dwingeloo 1 Emerges (12ish M ly) Nearby galaxy (only five times as distant as Andromeda) almost
obscured by our own Milky Way.
Ghostly NGC 2915 (15 M ly) A dwarf galaxy surrounded by a full galaxy-sized cloud of (atomic)
Hydrogen; just outside
Side-on neighbour (15ish M ly) Nearby Spiral Galaxy NGC 4945, only six times as far away as
The smaller of the two big spirals dominating
Milky Way Band Panoramic mosaic across 90 degrees.
Seen, with Jupiter, from the high Andes
IR GLIMPSE The galactic plane in infra-red
Wide angle deep exposure Seen in breadth and detail from Chile
Loop I in Northern Sky Large-scale structure in our galaxy, shown in rather pretty blobby
Nearby dust tapestry in IR
Ursus Minor's tail: Polaris
Two hemispheres, juxtaposed Star Clusters
Like its peers, our galaxy has a halo
clusters orbitting it (about 200 of them, in fact); and where a large cloud
of dust and gas
down to stars, once these have
away the remnants of the cloud, the
cluster (a.k.a. galactic cluster) is often a beautiful sight, shining
like jewels in a box.
Globular cluster M55 A tenth of a million stars, 20 k ly away, about 100 ly across.
NGC 1818: LMC globular cluster Unlike the globular clusters in our galaxy, typically 12 G yr old,
this one's actually young; about 40 M yr.
Omega Centauri, NGC 5139 The largest globular cluster orbiting the Milky Way, c. 10 million
stars, 150 ly across, 15
or 18 k ly away and
including stars about 12 G yr old – so it dates from when the universe
was about a seventh of its present age – yet it includes newer stars,
suggesting it may be the last remains of a small
galaxy captured by the Milky Way.
NGC 104, a.k.a. 47 Tuc 13 k ly away, 120 ly across and containing several million stars.
Globular NGC 2419 300 k ly away, almost twice as distant as the LMC
Open cluster pair NGC 869 and NGC 884, a.k.a. h Persei and χ Perseii, about 100 ly
apart, 7 k ly away and of roughly equal age: a
The Pleiades (a.k.a. seven sisters or M45); an open cluster of over 3000 stars, 400
ly away, 13 ly across; only
several degrees away
from the California nebula.
Twinkle, twinkle M3 stars RR Lyrae stars in M3, varying in brightness during the course of a
Open cluster NGC 290
Galactic cluster M39, in Cygnus
The great globular cluster in Hercules
Open cluster M25
M34, towards Perseus 0.2 G yr in age, about 15 ly across and 1.8 k ly away.
Globular NGC 6934
Globular M15 Milky Core
The centre of the Milky Way: a turbulent place ruled by a black hole –
or, at least, the orbits of stars near the centre imply the presence of more
than two million times the mass of our Sun (Swarzchild radius almost eight and
a half times The Sun's radius) in a space less than 17 light hours (under 123
AU or 26.4 thousand times the Sun's radius) across.
The Molecular Zone
Radio 1 metre wavelength, super-nova remants
The galactic centre radio arc
8 year IR movie Showing fast-moving stars in the central region.
Deep infra-red Close-up, 2 ly across, highlighting where
moves fast 17 light hours from the centre.
heart of our galaxy, in mid-infrared
Mega-star infra-red from 2MASS
Stars Spitzer's infra-red view of a 900 light-year-wide swathe of the
centre, 26 k ly away.
Dusty mess in visible light
ESO: Galactic centre
ESO: composite view
In X and γ … and theory predicts that an accretion disk can only produce
γ if it involves a black hole.
X-Flash in Milky Core Galactic Center X-Ray Flicker Indicates Black Hole
Infra-red and X-Ray Combined
Our Sun is in the same spur, between the two spiral
arms of the Milky Way, as the stars of Orion, after which this spur is
named. Orion's Great Nebula, M42, is a major stellar nursery, conveniently
visible thanks to violent winds from bright young stars, 1.5 k ly away and and
13 or so ly across.
Witch Head Wisps of dust
reflecting Rigel's light,
about 0.8 to 1 k ly away; a.k.a. IC 2118
Kleinmann-Low Nebula An explosion of red, with water-maser glow.
nebulae M78 and NGC 2071.
M78 and NGC 2071 in context
M78's treasure revealed
The Great Nebula
Belt, nebula and dust
South of Orion Reflection nebula NGC 1999, partly hidden by a Bok globule
Al Nitak, Al Nilam and Mintaka: blue
giants, c. 1.5 k ly away. Note horse-head in bottom left.
Fiery mess IRAS saw In infra-red, you see the clouds rather than the stars
Star colour cones Varying focus during an exposure to reveal colours
Hunter's profile Canaries Sky (La Palma) showing the nebulae and their structure:
Barnard's loop looks enough like a belly to make it easier to interpret the
constellation as a picture of a man.
Trapezium in warm Spitzer's IR
Wide view of all Orion
Al Nitak (a.k.a. Zeta Orionis) lights up the Flame Nebula; not far away, a
sheet of glowing gas which we see side-on serves as back-drop to another dust
cloud, whose shadow evokes the shape of a horse's head.
H-α Deep Field
Composite Deep Field
Nebulosities Composite picture: includes Horse-head, Flame and Orion Nebulae, with
Alnitak and other stars.
Through Comet SOHO Flame and Horsehead nebulae seen through a passing comet
Flame nebula close-up
Flame nebula in infra-red
NGC 2024: Flame nebula, in close-up
Barnard 33: The
Horsehead Nebula A dark nebula, seen in silhouette against an emission nebula behind it,
with a shape gently reminiscent of a horse's head.
Horsehead in context
Horsehead and Orion Nebulae
Same view, different light
Wisps around Horsehead
Horsehead in Pink Knights in HII satin …
Composite horsehead With blue emission nebula NGC 2023.
The Great Nebula in Orion Visible to the unaided eye as a fuzzy patch – just below and to
the left of Orion's belt – the Great Nebula rewards closer study. It's
a stellar nursery centred on a bright open cluster called The Trapezium. It
spans about 40 ly, lies about 1.5 k ly away and is expected to slowly disperse
over the next 0.1 M yr.
ESO-Hubble mosaic … from Hubble and ESO's La Silla (following day includes a
detail from it), looking like something from a picture by William Blake.
Hubble Mosaic Showing an inner region of width 2.5 light-years
Infra-red from Spitzer
Infra-red from Subaru Showing assorted things hidden in visible
Light and texture Near Infra Red from VLT
red and pink/blue
In SHO light
Contrast balanced for detail Pink, grey and brown dominate
Red demon, blue polyp
Trapezium clouds In the Center of the Trapezium
Portrait with neighbours
When a big star reaches the end of its life, it goes out spectacularly. The
remnants are often quite fascinating.
Remnant of Kepler's supernova, in X-ray The new star (
stella nova) recorded and studied
by Kepler and his peers in October 1604, without the aid of telescopes, gave
rise to the term nova; but it was actually what we'd now describe as a
type 1a supernova. This most recent stellar explosion in our galaxy happened
only 13 k ly away.
Sher 25: a pending supernova ?
Two in a distant galaxy Star Wars in NGC 664
RCW 86 in X-Rays 8.2 k ly away and 50 ly across; quite likely the remnant of a new star
recorded by Chinese astronomers in AD 185.
1994D by Galaxy NGC 4526 Supernova 1994D and the Unexpected Universe
Pretty SNR N63A Rampaging Supernova Remnant N63A; flames and dust
CTA 1's γ-ray pulsar
Simeis 147 Spanning 3 degrees in Taurus,
is 0.1 mega years old, 150 ly across, 3 k ly away.
IC 443 From a super-nova 30 k yr ago plus 5 k ly away; includes the Jellyfish
nebula; and Sharpless 249 appears nearby, between Mu and Eta Geminorum.
DEM L316: two bubbles of hot gas bumping
N49's Cosmic Blast In the LMC; it ejected a
bullet of gas at
almost light / 150, leaving a magnetar behind.
E0102-72 in the SMC
A pulsar's hand juggles a crown
Jellyfish nebula and Sharpless 249
SNR 0509: rippled red ribbons (and mysteries)
Vela A super-nova about 11 k yr ago ejected a shock-wave so fast it still
travells a mega-metre in about seven seconds, producing a rippled sheet of
glowing gas as it hits its surroundings. This remnant's diameter is about 100
ly, so the shock-wave's average speed has been around c/220, roughly ten times
its present speed.
Runaway Star HD 77581 hurtling along under the influence of SNR pulsar Vela X-1
The pencil nebula Part of the remnant, seen edge-on; 800 ly away and 5 ly long.
Loop, a.k.a. Veil Nebula Whispy remains of a super-nova seen on Earth about 7.5 k yr ago; as the
shockwave hits nearby clouds of gas and dust, it glows prettily. It's about
1.4 k ly away and around 70 ly across.
Cygnus X-1 The black hole left behind by the supernova may well be a microquasar;
the relativistic jets of gas bouncing off its acretion disk cause a bubble
nebula rapidly expanding outwards from it, near
HOS: Cygnus Loop
The Veil Nebula
Witch's Broom NGC 6960, West end of Veil Nebula
Eastern Veil in HO light
Pickering's Triangle Slightly South and East of the Witch's Broom
NGC 6992: more pretty filaments
X-Ray images of remnants
Ejecta from the explosion spread outwards, bashing everything they meet so
hard they dislodge even the inner electrons of heavy elements – making
them bright even at high energies. Several of these images are from the
Tycho's X-Rays from the remnant of the supernova Tycho saw in 1572.
a sponge !
Jelly N132D and the Color of X-Rays
Small Star Explodes Type 1a supernova, DEM L71 in LMC, white dwarf ejecting stuff that
fell onto it from its companion.
SN 1006 Remnant of a star first seen a millennium ago, in
X-ray, optical and radio.
Ribbon among the remnants of SN 1006
Elements in the aftermath
SNR 0103 72.6: Oxygen Supply X-ray image of an SMC SNR. Pretty blobs of false colour ;^)
IC 443 Not only is its neutron star
centre; its wake points in the wrong direction, suggesting vigorous flows
in the remnant gas. About 5 k ly away and 65 ly across.
The crab nebula
M1: remnant from a supernova witenessed in 1054 CE.
HII/X composite of pulsar
X-ray image of its wind nebula
HST: complex filaments
IR/visible/X composite of nebula With the neighbourhood of the pulsar plainly visible inside
From the VLT
Expanding Animation showing difference across 28 years
Fine detail From the Norwegian Optical Telescope.
Cassiopeia A Remnant of a supernova seen on Earth c.1700, ten millennia after it
In X-Ray Pretty coloured flecks in round blob
Light Echoes in Infrared
The supernova of 1987 Formally known as SN1987a, in the Large Magellanic Clouds.
The neighbourhood A Supernova Starfield
Shock-ring Shocked by Supernova – debris at c/18 hitting material ejected
before the supernova.
Fireball Resolved With inset images of the central explosion
Miscellaneous fuzzy blobs in the sky. See also: Emission
TT Cygni: Carbon Star
The Puzzling Cone 2.7 k ly away,
near S Monocerotis
Barnard 68 The total darkness of a molecular cloud, 500 ly away and half a light
CG4: Pac-Man A ruptured cometary globule; Pac-Man on his way to eat a galaxy; but
actually one end of a
larger gas cloud. Closer
in, it reveals NGC 281
Dust around Polaris
Antares' dark river
Wide field around the dark river
The dark doodad
Auriga deep field
Seagull and Duck
Star cloud IRAS 05437+2502
Aries's dust clouds and van der Bergh's stars Zeta Ophiuchi's bow-shock Not
really a nebula, but a fuzzy blob anyway; Zeta Ophiuchi is moving fast through
interstellar material, likely after being launched away by a dying
and the accompanying Flaming Star Nebula, IC405. The star is actually
a refugee from Orion, escaping at 90 km/s (Auriga, the charioteer, would be
proud), and the Nebula is a dust cloud it just happens to be passing
In red again
From CFHT Lone star
One star is all it takes to make a dust cloud pretty.
IC 4592: head of dragon (or horse)
Nicely shows that dust cloud black just
needs light to be blue.
Bubble hits cloud
Pretty Bubble Nebula NGC 7635: 10 ly
bubble blown, by bright
blue Wolf-Rayet star, in a giant molecular cloud
California and comet Holmes
NGC 1499: California H-glowy cloud illuminated by Xi Persei
NGC 7023: Iris Bright
makes surrounding clouds of
muck glowy; 1.3 k ly away, c. 6 ly across.
Pistol The brightest star yet known, Pistol star (100 sun-mass, 1e7 times as
bright), and the nebula it's shed.
T Tauri and Hind's variable nebula The cannonical
T Tauri variable,
beside a dust cloud in which a star is
stars together can achieve some major impact.
Pismis 24 and NGC 6357 Several big stars and an
in which stars are being born; see following day for context.
Fox Fur Fluff round
young open cluster; image with
Fox fur in unicorn or christmas tree
Fox Fur Blur Blur round young open cluster; image showing the cloud clearly, stars
a bit dazzled.
Dust, Stars, Corona Australis
Bright blobby star light Dust and Gas Surrounding Star R Coronae Australis
IC 410's tadpoles Blobs with tails swept by galactic cluster 1893, which IC
hides: in SHO light;
70 ly across, 12 k ly away.
UV-blown dust Hot Stars in the Southern Milky Way
IC 5067, the Pelican Nebula an emission nebula in Cygnus, 2 k ly away; in true-colour, but hover
for synthetic colour from spectra of Oxygen and Sulphur.
Pelican protostar detail Herbig-Harro 555 in the tip of a dark tendril seen against IC
Rho Ophiuchi The Colorful Clouds of
Rho Ophiuchi in IR, showing young stars
Rho Ophiuchi wide field
Dust lit up by an open cluster
NGC 6188, home to the Ara OB1 association,
an open cluster whose core is called NGC 6193; all 4 k ly away in the galactic
disk. Neighbour to NGC 6164.
NGC 6188 in SHO light
Dark tower NGC 6231 This cometary globule in Scorpius, shaped by NGC 6231's illumination,
spans almost 40 ly and is about 5 k ly away.
A particularly pretty fuzzy blob, 3 k ly away in the constellation Monoceros
HOS Rosette See the
above photograph link for best results ;^)
Rosette in context
Rosette close-up Showing dark filaments of dust cloud sculpted by hot young stars 3 k
Detail in SHO
In pink and blue Wolf-Rayet stars and their surroundings.
Wolf-Rayet stars are so energetic they destroy themselves. In the
process, they make pretty things.
WR 124: Stellar Fireball Wolf-Rayet star, nuking itself into oblivion
NGC 3199, blown by the wind from a Wolf-Rayet star
Wolf-Rayet NGC 6888 (WR 136) in SHO light Sulphur, Hydrogen and Oxygen light from a 25 ly-wide bubble around a
hyperactive star 5 k ly away.
H-Alpha Thor's Helmet
Thor's Helmet A cloud of dust being
puffed about by a
big blue Wolf-Rayet star, with hints of emerald due to
Oxygen in the cloud. Also known as the duck
Crescent Nebula's edge
Sharpless 308: 60 ly-wide Oxygen bubble
The birth of stars is a dramatic process – and often pretty.
Radio Cygnus Blobs and filaments in pretty-lit clouds
N81: SMC cluster cradle N81: Star Cradle in the SMC
Barnard 7 and friends Dark dust clouds: where stars are conceived.
NGC 602: SMC cluster nursery Whispy clouds left behind as new-born stars blast aside the dust-cloud
in which they were born, spanning 200 ly.
IR: dusty NGC 1333 Revealing the innards of a
nebula, 1 k ly away towards Perseus
RCW49 in IR Building Site, seen by Spitzer in infrared, exposing young stars and
probably protoplanetary disks.
NGC 7129: newborn stars
NGC 604 The largest stellar nursery in our Local Group. Big hot young new
stars blast caverns,
filled with X-ray-emitting
gas, in a dust cloud in spiral galaxy M33, Triangulum, a.k.a. Pinwheel.
Still Life Dusty nebulae and hot stars in Monoceros
IC 5146 in Cygnus
– puffy clouds, well lit by a 100 k yr young
star, c. 4 k ly away.
NGC 3576 9 k ly away, 100 ly across, in the Sagittarius arm of the Milky Way.
Cradle to Grave NGC 3603: from beginning to end, Sher 25 and its neighbours
NGC 6334: Bear Claw or Cat's Paw
Massive stars forming in a cloud …
All kinds of mayhem Stars, Dust and Nebulae in
NGC 2170: more mayhem
Amid the dust, blue
reflections and red emissions, infra-red
reveals stars forming.
Southern Crown's Coronet in radio and X-ray
Hubble X Pocket of light in the distant darkness
M17: Star facrories in SHO light
M17: Omega a.k.a. Horseshoe, or Swan. 5.5 k ly away, 20 to 50 ly across
RCW38 in IR Star Forming Region RCW38; looking though its dust-cloud veil using
IC 1795 in SHO light
Detail within the heart nebula
The heart nebula, IC 1805 and
its central region
Its companion, IC 1848, a.k.a. W5, in IR 200 ly across; pressure waves from the inner stars'
are provoking the surrounding clouds to
form new stars.
Heart and Soul
Two cute blobs about 6 k ly away in
Cassiopeia (in the Milky Way) spanning 300 ly and full of young open
Heart and Soul in IR
Northern Trifid NGC 1579 – not to be confused with M20. It's in Perseus, about
2.1 k ly away and about 3 ly across.
Cepheus's NGC 7822 in SHO light
SHO NGC 7822 in context
Spider (IC 417) and Fly (NGC 1931) NGC 2174, in Orion New-born stars
shrug off their natal shroud.
North America nebula Infra-red view
shows stars through the dusty cocoons that hide them from visible view.
Carina Nebula An even larger star-forming region than Orion, over 300 ly across, NGC
3372 looks (to me, in some views) like a flint arrow-head, with the keyhole
nebula embedded in it. It's the context
Carinae, which lights it up, sculpts it and may one day blow it to
smithereens; so I'm glad its 7.5 k ly away.
Carina and the Jets Visible light image of a dust pillar; with onhover equivalent in
infra-red showing internal activity from a new-born star.
Jewel in the southern sky
Keyhole, NGC 3324
Mountains of dust in NGC 3324
Carina Clouds Includes
Carina's shroud Sculpting the South Pillar
Filaments of dust and glowing gas
The Great Nebula in Carina
In SHO light
Ten degree context Single star views
When we can distinguish a single star forming, we can sometimes almost make
out what's orbiting it…
Newborn LkHa101 The Hole in the Doughnut; in infra-red, the debris cloud surrounding
the new star shows bright and clear. Watch closely for new planets
S106: hourglass with wings Star Forming Region Sharpless 106 in infra-red, home to many brown
Sharpless 171 in SHO light 3 k ly away and 20 ly wide, seen in light from S
+ (red) as
red, H (actually red) as green and O ++ (green) as blue.
Cosmic Tornado HH49/50 Jet blasted out by young star, hitting inter-stellar gas, 450 ly
RY Tauri 450 ly away, 2/3 of a ly across; a molecular cloud being blown away by
the star it's created in its heart.
The winds from hot young stars, or the shock-wave from a supernova, can
compress and agitate a cloud of dust and gas, provoking the formation of new
Breeding Bubble RCW 79: gas bubble, blown away by bright hot young stars, collides
with interstellar muck and causes yet more stars to form.
RCW 49: Westerlund 2 in X and IR
Cygnus Wall The Cygnus Wall of Star Formation, in the North America Nebula.
Mountains of creation Infra-red view of cold gas and dust 7 k ly away in Cassiopeia,
spanning 70 ly, with a few embedded stars.
Young Stars of NGC
346 210 k ly away in the Small Magellanic Cloud; stars can be bright even
before they start fusing Hydrogen.
Henize 206 Cosmic Generations; a supernova remnant triggers new stars forming in
the Large Magellanic Cloud.
Carinae A star with suspected suicidal leanings, vigorously
Dust and Eta Carinae in IR
The Homunculus Nebula A
dumbel of ejecta from Eta Carinae's
Victorian burst of vigour.
The Trifid Nebula
About 50 ly across and 5 k ly away, towards Sagittarius; also known as M20.
Polychrome The Trifid Nebula from CFHT –
Inner centre Filaments of dust highlit by stars behind
Horns Pillars and Jets in a corner of the Trifid nebula, looking like a
monster's head with long straight horns.
Trifid Nebula, M20, seen with surrounding
star-field, part of Sagittarius.
in context from AAO. Shows neighbouring reflection nebula as well as nearby dust
In RGB visible light
The Lagoon Nebula Over 100 ly across, about 5 k ly away in Sagittarius; also known as M8.
Hydrogen and dust
In H, S, O
In H, Si, O The busy center of the Lagoon Nebula in three colours
Gas, dust and stars
In re-mapped colours
Twist Glowy clouds elegantly framed by dark ones.
East of Lagoon
Sagittarius triplet Lagoon and Trifid
With and without stars
Mixed broad- and narrow-band image
Southern cliff, mixing visible and IR
2 k ly away, about 20 ly across in the constellation Cepheus; seen at right in
Oschin's Red and Blue … in which, for scale, one can spot molecular
Barnard 163, within which stars a likely
In H light
SHO light Glowy cloud with dusty intrusions and baby stars
Elephant's Trunk in SHO light
Glowy Elephant's Trunk An Unusual Globule in IC 1396. Nice glowiness with crisp obstacles
and bright stars.
Study in brown The Eagle nebula
M16: 20 ly wide birth-place of an open
cluster, 6.5 k ly away.
In three spectral lines
In infra-red (Spitzer)
in three spectral lines
X-rays and The Pillars of Creation
Clown Infrared Star Hunt; I see a clown's face ;^)
Fairy a dust pillar sculpture
the Large Magellanic Cloud
Assorted nurseries in one of our home galaxy's close satellites.
Fine detail from Spitzer in IR
An LMC Star Cloud N11B dust cloud with new-forming stars
Sea-horse dust cloud
Super-bubble N44, without so much context,
in such light as leaves it looking like a face.
DEM192 in LMC A Star Forming Region in the LMC; evident signs of explosions.
Colour-coded by elements producing the light.
LH 95 in detail High resolution image of a star-forming region, taken in carefully
chosen spectral lines so as to glean more information about star
The Tarantula Nebula The largest, most violent star forming region known in the Local
Group, it's about 1 k ly across and 180 k ly away. Also known
Tentacles of Tarantula Includes a link to an ESO page which lets you zoom in to see fine
later edition of part of the same field
links to a remarkable run-away.
Star cluster R136 emerges Shaping the Tarantula with the force of the winds from
big hot new stars, among the hottest and
Tarantula's Hodge 301 Star cluster Hodge 301, a Denizen of
Tarantula Nebula, with red giants due to blow, seeding the nebula with
more pressure waves to make more stars.
30 Doradus (a.k.a. Tarantula) in X, UV and Hydrogen; supernovae in the cradle of
a globular cluster.
The Tarantula Zone and Doradus is in an area called Dorado
Web of fillaments
Planetary Nebulae: when a star of modest size
(such as our Sun) grows old, it sheds its outer layers. The results can be
Planetary Nebula Show cycling gif, with links to lots of examples
Stingray Hen 1357: New Born Nebula
NGC 6751 Stringy iris-like nebula round old dying star
Blinking Eye NGC 6826; planetary nebula
NGC 2818 in NHO
NGC 7008: the foetus nebula
Little NGC 7027 in IR Only 14 kAU across …
IC 4406: side-on cylinder
Spirograph IC418 went boom, now it's surrounded by cute filaments of glowy stuff
Star gone boom – surrounded by fronds and glowy-ness.
Little Ghost Eye-ball in the sky with a white dwarf in the middle, whose boom made
NGC 2440: Cocoon of a new white dwarf
NGC 2440: Hottest known white dwarf 4 k ly away, 0.2 M K hot, surrounded by a 1 ly wide planetary nebula.
NGC 6210: Turtle Red outer cloud being blasted from within by jets of hotter gas.
NGC 6369 Donut Anular planetary nebula in Ophiuchus
Symmetric NGC 5307 Pretty blob of a planetary nebula.
NGC 7009: Saturn The Saturn Nebula, a low-mass white dwarf
Ghost of Jupiter 1.4 k ly away, with mysterious red side-flashes
Blue Snowball FLIERs around the Blue Snowball nebula.
The Skull Nebula NGC 246: 2.5 ly across, produced by the dead member of the binary it
surrounds, 1.6 k ly away.
Mira and its UV tail
Medusa, or Abell 21
LL Pegasi's unusual spiral, IRAS 23166+1655 Gaining a fresh layer per roughly eight centuries, as a dying star and
its partner orbit one another.
Methuselah: MWP1 Ten times as old as the typical life-time of a planetary nebula.
Necklace in NOH light
Red Square nebula
The halo of NGC 2438 Bipolar lobes
Many planetary nebulae have a pronounced spreading along an axis.
Red Spider Planetary Nebula, NGC 6537
Bipolar NGC 6164-5 4 ly across, 4 k ly away, complete with a few cometary knots
Rotten Egg aka Calabash nebula, OH231.8+4.2, in Puppis.
Mz3: The Ant
MyCn18: an hourglass Cthulu's Eye !
Egg's Searchlight Beams
Polarized Boomerang Pretty false-colour pattern
Butterfly Twins NGC 2346; two stars in mutual orbit feeding a surrounding cloud
Wings of a butterfly M2-9, 2.1 k ly away; two stars orbiting in a cloud cast off pretty results.
Butterfly close-up NGC 6302: early image from 8.2 m Very Large Telescope in Chile.
Renewed Hubble's Butterfly NGC 6302; compare Hubble's
image. Hollow spaces
Sometimes, the star hollows out a bubble
in the middle of its planetary nebula, generally with beautiful results.
NGC 3132: Eight Burst Cloud hollowed out by star boom and glowing in its light, with
decorative dust wisps to make it prettier.
IR Helix and its dust
NGC 7293: Helix Nebula of a nearby star dying, with
knots; seen in infra-red by Spitzer; 2 ly wide, 700 ly away in
Spherical Bubble Planetary Nebula Abell 39
NGC 7635: the bubble nebula 10 ly across, 11 k ly away, blown in a molecular cloud by a star 10 to
20 times as big as our Sun. See in H-α, or
M57: Ring Cool glowy eye-like
Rosy round the Ring M57 with its surrounding rings of
redness; also available in diverse shades of
Annular Shapley 1
M76: The Little Dumbbell
Similar in form to M27 (below), but
fainter; 3 to 5 k ly away, over one ly across.
The Cat's Eye Nebula
NGC 6543 is a planetary nebula, over half a light-year across, about 3 k ly
away but looks a bit like a deep-sea blobby life-form. It's filamets and
inner folds are marvelously intricate. It is surrounded
by an outer halo that spans three light
X-ray and visible
the inner details there's
another layer of complex structure.
Light Echoes 20 k ly away, in the constellation Monocerotis, on the edge of our
galaxy, a quite unusual star, V838 Mon, had an outburst: the light from that
first came to us directly in January 2002; but now we get to watch the light
illuminate the surrounding cloud – the outer layers the star had
The Echoes Begin first signs of oddity; 2002, May and September
February and October
Dumbbell About 1.2 k ly away, over 2.5 ly across; also known as M27.
Glowy Dumbbell Star boom left-over in glowy colours
In H+O synthetic colour
In context, again in H+O colours Alien Planets
As the Sun is just an ordinary star, surely other stars may have
satellites like the planets of our solar system. As our astronomical equipment
has improved, we have begun to catch glimpses of these companions; and even
launched specialist space probes to look for them; for example, in 1/400 of the
Kepler probe has found over 1200 possible
exoplanets (and it can only see ones whose orbital planes pass through
β Pictoris A star 50 ly away, with a debris disk like our Kuiper belt
a probable planet (giant) in an orbit
roughly as large as Saturn's.
Formalhaut's visible planet Only 25 ly away, Formalhaut is young: its surrounding debris ring
hasn't stabilized into the serene splendour of a system of planets, but one
planet is visible among it, about three times as massive as Jupiter, with 14
times the orbital radius.
Young star, hot planet 500 ly away a newly-formed sun-like star is observed, in infra-red,
confirmed) to have a
companion. Estimated to be about 8 times as massive as Jupiter, it's 330 AU
(1.9 light days) from its star – 63.4 time as far as Jupiter is from our
Gliese 581's habitable zone It's only a red dwarf, but (to the best of 2007's knowledge) has a
planet a bit bigger than Earth orbiting it once every 13 days, at such a
radius as to have a likely
surface temperature of
zero to 40 Celsius. With a mass estimated to be 5 times that of Earth, and a
diameter 1.5 times that of Earth, its surface gravity is about twice that of
Earth. This is 20 ly from home.
Gliese 581g: Zarmina's world Further study of Gliese 581's system of planets had, by 2010,
identified a planet (not sure if this is better data on the same as above, or
a different one) in circular orbit with period 37 days; relative to the
matching properties of Earth, its mass is 3.1, orbital radius 0.15, body
radius 1.5, surface gravity between 1.1 and 1.7.
Several planets, one star Rather further afield, 130 ly away, HR 8799 has 1.5 times the mass of
our Sun and is seen (in infra-red) to be orbited by at least three gas giants,
likely bigger than Jupiter, all with orbital radii larger than that of
CoRoT and its rocky planet 7b
Kepler 11's compact solar system Near Neighbours
We can more readilly learn about stars nearer to us.
Sol's Local Bubble Our Galactic Neighborhood (schematic); and
The Gum Nebula Named after Stanley Gum (1924–1960); a near-by ancient super-nova
remnant, from 450 to 1500 ly away.
Proxima Centauri The nearest star to the Sun, 4.22 light years away; so faint it wasn't
found until 1915, despite being in orbit around
fourth brightest star in the night sky.
It looks so serene and perfect until you study it closely and discover that
it's a raging inferno in perpetual turmoil. Galileo was the first to see it
thus; since 1995 the SOlar and
Heliospheric Observatory, in Earth's L1 Lagrange point, has hugely
enriched our knowledge of our nearest star's tumult.
ISS's spotless transit
Stereo Sun in red and blue
Great Ball of Fire A Great Day For SOHO – returned to service.
Plasma flows Solar surface and near-surface plasma flows relative to an average rate
of surface rotation.
Spicules: hot plasma
Blue by inverting H-α
Blue in Fe 11+ UV
daily images of the sun.
Close-up details of surface activity
In Iron's ions' light at equinox Spots, flares, prominences and coronal mass ejections
Despite the fierce gravity at the Sun's surface, there's so much
activity at the surface that some of the matter escapes; some even hangs
suspended above the surface – known as prominences when seen at The
Sun's limb, against the dark back-drop of space, or as filaments when seen
against the The Sun itself.
Prominence Erupts Eruption on the
hellish surface, in He UV.
Prominence in profile again, in He UV, from STEREO (Ahead).
Coronal Rain, Solar Storm
Sun Inferno A Solar Filament Lifts Off
Plasma Slinky AR9077: Solar Magnetic Arcade
Sunspot 875 flares
Plasma TRACE An Active Region of the Sun
Neutrino image Super Kamiokande's 500 day exposure
Surface ripple Solar flares cause sun-quakes
Sun-spot side-view from Hinode
Sun-spot in UV Showing violent electromagnetic activity around AR 9169 on
quiet day in September 2000.
Huge prominence suddently erupts
Extreme UV from the SDO
Filament in SDO's extreme UV
Big complex flare up, from SDO
Solar prominence, from SOHO
SDO movie of a long filament erupting
Plasma splurge Eclipses
By a happy coincidence, we are living in an epoch in which the Moon's distance
from the Earth (which slowly increases) is in the same ratio to the Moon's
diameter as the ratio of the Earth's distance from the Sun to the diameter of
the Sun – to an approximation good enough that routine variations in the
distances involved suffice to make each ratio sometimes larger than the other.
Consequently, when the Moon passes between Earth and Sun, it can exactly mask
out the whole of the Sun's body, revealing its magnificent corona.
Crescent Sun: Solstice Eclipse
Annular, behind palm trees, 1992
Corona, Mercury, stars
Both edges of totality The last moment before, and first after, a total eclipse, seen from
Novosibirsk. The Sun shines through lunar valleys.
The corona in all its glory
Eclipse over China's Great Wall With all but Jupiter of the classical planets visible.
Moon and Eclipse corona
Eclipse over Zambia
Antarctic eclipse, 2003
Eclipse over Turkey Time-series showing the moon encroach on, hide and move away from the
Diamond ring and Bailey's beads Time-series from Novosibirsk, showing the effect of the Sun shining
through the Moon's valleys.
Silhouettes over Goa
Six minutes and fourty-two seconds
Bailey's beads pierce clouds
Rising over Poseidon's temple
Detailed view of the Corona
Total eclipse behind Easter Island Maoi … and as a
Same eclipse, over the Andes … and the
shadow cone it cast
Same eclipse, high dynamic range Revealing details from the bright corona to the lunar surface seen in
Diamond rings refracted to shadow bands
Rising eclipse over Graz
Hiding the midnight Sun
Planet Satellites of our Sun which: are big enough that their own gravitation
obliges them to be roughly spherical, and; constitute most of the mass in
orbits near their own; are classified as planets – or
planets, to distinguish them from Pluto, which
also gets described (mainly thanks to historical accident) as a planet. The
eight major planets fall into two groups, separated by the asteroid belt: the
four outer planets are gas giants, of low density thanks to vast amounts of
Hydrogen in their atmospheres; the four inner planets are much smaller balls
of rock, with atmospheres (where present) dominated by less cosmically
abundant – but weightier – substances.
Named for the messenger of the gods. Has negligible atmosphere. NASA's
Messenger probe has, in early 2008, made the first of a series of fly-bys that
shall ultimately put it into a mapping orbit on 2011, March 18th; it has
already greatly expanded on the limited data from the one earlier visitor,
Mariner 10, in 1974. In 2013, Europe and Japan shall launch a joint mission
to Mercury, Bepi-Colombo, which shall include X-ray sensing.
Transit: crossing the Sun's face, amid clouds
Mariner composite Full disc, with obvious alien landing-strip.
Half-face Mariner 10, 1974
Degas Ray Crater
The other half Messenger's
first look at what Mariner 10
Craters close up, from terminator to horizon
A view from Messenger's second fly-by
Rembrandt impact basin
Mysteriously dark crater-hub
Double ring's surprisingly smooth interior
Messenger's first view from orbit
Close-up exaggerating contrast
Named for the godess of love. Venus is a common way-station for space-craft
heading out to the gas giants and beyond; it provides a
Its atmosphere is apallingly corrosive, immensely thick and hot – the
first few space-craft we sent there were destroyed before the reached ground
Transient At intervals
bit over a century, Venus and Earth manage to line up twice, eight years
apart, in such a way that observers on Earth see Venus pass across the face of
the Sun. It happened in 2004 and it'll happen again in 2012.
Venus-scape Atete Corona and surrounding features
Rock domes The surface was once molten, as Magellan's radar made clear
en passant Galileo's fly-by picture of Venus
Arachnoids Surface mess; fractures forming concentric ovals and complex networks;
Radar surface View through Venus' clouds thanks to Magellan's imaging radar, with a
bit of help from Arecibo. Resolution is 3 km.
Optical Our home's boiling cloudy twin.
UnVeiled by Magellan's radar, naturally.
UV×4 from Stereo Ahead
Sulphuric acid clouds Noticed by ESA's Venus Express probe.
Atmosphere revealed in crescent
South polar vortex
The planet on which I was born.
Big Blue Marble
Earth at Night That famous planet-wide composite …
True Color Cloudless daylight composite
Siblings Earth and Moon
Seen from afar Moon passing Earth, seen from 50 Gm away by Deep Impact.
Two South Poles Earth and Moon seen by NEAR
Apollo 17's view
NEAR-view A Passing Spaceship Views Earth, on its way from Mathilde to Eros
Ultraviolet View from the moon ;^)
Phytoplankton Ocean Planet Pole To Pole – false colour skewed to emphasise
Big Ozone Hole, 1998
Double Ozone Hole, 2002 False colour maps of ozone levels
Water Vapor Image in 6.7 micron IR.
El Nino Water Rhythm Pacific warm-water picture.
Temperature Map With link to updates
Antarctic summer As seen by Galileo during 1990 fly-by
Sahara: Richat Structure
Sahara: Terkezi Oasis
Bay Area from Landsat Landsat 7 Views Planet Earth
Katrina making waves Hurricane Katrina in the Gulf of Mexico, as seen from GOES-12. Very
neat central hole.
Ivan the Terrible 2004's Hurricane Ivan, seen from the ISS.
Crescent view Seen by Rosetta, on its way out to rendezvous with a comet.
With Moon, as seen from near Mercury
During an eclipse, as seen by Mir
Named for the god of war. When at its closest to us (in opposition,
i.e. opposite the Sun), Mars shows us its full day-lit face; given how thin
its atmosphere is, this has given us a nice clear view of its surface. When
the best telescopes couldn't quite resolve the details, but nearly could, its
surface features looked tantalizing almost comprehensible – leading to
some rather fanciful guess-work.
Pathfinder's rusty sunset
A rock called Yogi
Gale crater: Curiosity's target
Viking views What our first robots found when they got there.
Valles Marineris The Grand Canyon of Mars
Viking Mars Seems to be the complement of the Valles Marineris picture. Provides
links to lots of on-line literature about Mars.
Schiparelli-centred full face Big crater.
Phobos Over Mars
The infamous face Among thousands of hill-ish shapes in pictures, it should be no
surprise that at least one vaguely resembled a pattern our brains are
hard-wired never miss, at the expense of sporadic false positives. Sure
more recent pictures show a less
Seasonal water ice
In 1997, NASA's dedicated survey mission arrived and went to work – now
we have really good pictures of all of Mars, from close up.
Olympus Mons Sun-set over a 24 km tall extinct volcano that's 64 km across.
Rock strata in Marineris Stratified rock visible in mountain (amid dust desert).
Marineris detail In A Grand Canyon On Mars
Victoria Crater 800 metres across, 70 metres deep, c/o Opportunity rover
Schiaparelli Coastline Ancient Layered Rocks on Mars, in Schiaparelli Crater.
Volcano and clouds Volcano Apollinaris Patera
Nanedi Vallis Martian River Bed ?
Proctor crater's dunes Mars Global Surveyor's view of blobby dune array.
Glint Distorted image from Global Surveyor at noon
Topography Mars Orbital Laser Altimeter chart
Layered hills of Arabia Terra
ESA's orbiting observer arrived at the end of 2003. Its passenger, the Beagle
2 lander, failed; but the satellite has sent back some fine imagery.
4 km cliffs at Echus Chasma
Ice-pool in Crater Water Ice in a Maritan Crater – just begging to be domed over
and warmed to make a lake.
Steep cliffs North polar region, in a mish-mash of materials, with cliffs
approaching 2 km in height.
Cydonian mesas Mars express image, including
The Face, which was shown in
closer detail the previous day.
and Opportunity Also in 2003, NASA sent two Mars Exploration Rovers, which (having
landed safely, unlike Beagle 2) have been sending back excellent images long
after their original design lifetimes of 90 days. They travelled separately
but both landed in January 2004. Spirit explores rocks and hills within Gusev
Crater while Opportunity, half a world away, visits a selection of smaller
Gusev Crater Sprit's
Inside Eagle Crater Opportunity's landing hole, a small crater in Meridiani Planum.
Tiny hematite spherules
Bonneville Crater panorama
Layered rock in Endurance Crater
Opportunity's heat shield's crater … and a nearby
Friendly dust devils
Sunset over Gusef Crater
View from Husband Hill
Bumpy Boulder found at Spirit's winter quarters
Spirit's doodles on Engineering Flats
The rocky road to Victoria Crater
On the brink Opportunity studies the cliffs beside which it'll make its fateful
Opportunity's desolate panorama Three years later, on its way to Endeavour crater, checking up on a
possibly other-worldly boulder.
Intrepid Crater Still
en route to Endeavour, another small
Spirit's last panorama: Gusev crater
Reconnaissance Orbiter Launched in August 2005, the MRO is dedicated to looking for signs
that there was ever persistent water on Mars's surface. It reached Mars in
March 2006 and has since been sending back a wealth of excellent images from
Opportunity's way down Seen from above while searching for a
down into Victoria Crater.
Sprit in the Columbia Hills
A hole … in Mars – not Blackburn, Lancashire.
A later close-up revealed near-vertical walls.
Layered rocks in Aureum Chaos
The sandy layers of Chasma Boreale
Vast buried glaciers ?
Suspected mud volcano
Barchan dunes flowing down-wind
Melting dunes near the North Pole
Proctor crater's dunes
Views from Earth
or, at least, from Earth Orbit – mostly from the Hubble space telescope:
Spring arrives 1996 September
Summer starts HST scouting in March '97 ready for Pathfinder and Global Surveyor.
Summer's End View from Hubble a week before Pathfinder landed, 1997 June 27
Autumn Begins 1997 September 12
HST pair Images about a quarter turn apart.
Engulfed The Great Sand-Storm of 2001
Spring storm, 2010 Spring on Mars usually implies dust-storms; Northern spring happened
in 2010 just after opposition, giving a good view.
Named for the king of the gods.
Rings, discovered by Voyager
Eclipsed Galileo's ring-side view
Unrolled Cylindrical projection.
Aurora Jupiter's pole with a crown of auroral light.
Direct hit Jupiter Swallows Comet Shoemaker Levy 9
A later impact scar Results of a comet-strike, causing a dark
tracked during the subsequent months. … and a
close-up view, c/o Hubble.
Jove's Clouds from Cassini, and
from New Horizons.
Infra-red cloud view Showing off the power of adaptive optics to improve ground-based
Sofia's first light Comparing Jupiter in visible light and IR, the latter seen from
Earth's stratosphere, clear of the troposphere's water vapour.
Great Red Spot Amid its bands of stormy clouds, fast-spinning Jupiter
storm; Hooke (1664) and Cassini (1665) first described such features, one
of which may be the same as has been consistently observed since the
1830s. With extents of 12–14 Mm in latitude and 24–40 Mm in
longitude, the area it covers is roughly equal to the total surface area of
Great Red Spot movie Approaching Jupiter, Voyager 1 took a succession of pictures of the
GRS; one of these has since
Storm's tail West Of The Great Red Spot, colour-coded to show cloud height and
Storm clouds over The Spot
Galileo close-up of Red Spot Computed, from three filtered images, to get true colour.
Red Spot Conjunction The Great Red Spot has a companion (2006) and they've even passed
quite close to one another.
Spots: three red, two white A third red spot had developed by May 2008; all three are seen
together here, along with a couple of white spots.
RIP Baby Red Spot, May–July 2008 Eaten by the Great Red Spot during a three-way collision with Red
Jove and its satellites
Various probes visiting Jupiter have captured excellent pictures of
the planet, often accompanied by its moons.
Io (snitch), by Jove
Io over Jove's clouds (B+W) Voyager 1 pic from 5 Million Miles From Io looking down on Jupiter,
in black and white.
With Io, from New Horizons as it passed by
Rich color, with Io and Ganymede's shadow, too.
Ganymede, by Jove
Jupiter eclipsing Ganymede
Triple Eclipse Io, Callisto and Ganymede together
Europa and Callisto, by Jove
Jove and Family Jupiter and its four Gallilean satellites.
Named after the father of Jupiter.
In true colour, with Titan
From beyond Looking over Saturn's shoulder in 1980 just after passing it; Voyager
au naturel Saturn in true colour, with Enceladus dot in front of it; as seen by
Hubble, while Cassini was en route.
Cassini (VIMS): across the infrared spectrum
In infrared, with aurora showing
Colours, rings and moons
Moons in transit Enceladus, Dione, Titan and Mimas, as the rings approach edge-on.
Long-lived electrical storm Wider than the Earth and over three months old.
South polar storm Slightly bigger than the Earth, with winds over 150 m/s (550 km/hr);
and it's probably been going for giga-years.
Spanning a band in the Northern hemisphere
from late 2010.
Cloud systems around the South Pole
Seen by Lunar Limb
Grazing Lunar Limb
Seen from above a pole
hexagonal cloud ring
Aurora over north polar cloud glow
Yearly variation in tilt
Crescent view just after equinox The Rings
Visible, even with early telescopes, from Earth: we now know that the other
gas giants have ring systems, too, but we knew about Saturns's first.
Ring-waves A Wavemaker Moon in Saturn's Rings (Keeler gap).
Ring particle size map Particle Sizes in Saturn's Rings – Cassini sent radio waves
home; reception revealed data on particle sizes in the centimeter range; there
may well be bigger ones …
Silhouette From deep in Saturn's shadow, Cassini looked towards the sun and
caught a beautiful view.
Epimetheus, rings and Titan
Dark side of the rings
Ring through-scatter Saturn's Rings from the Other Side – seen with sun behind
camera but on the other side of the ring plane.
Earth seen through the rings
Spokes near equinox
Intricate details at equinox
The huge enveloping dust ring Newly discovered in late 2009, with a radius over fifty times that of
Saturn's E-ring and thicker than several times Saturn's radius.
… and their shadows
The rings cast shadows on Saturn, with often pretty effects. As a
bonus, near Saturn's equinox (2009/August), Saturn's moons and the rings cast
shadows on the rings themselves, revealing details of their structure that
would otherwise be hard to see.
Ring-side view Cassini spacecraft crosses Saturn's
By the light of the razor ring Polarized IR revealing how much a 1 km thick band of rubble can
Thin vertical line
Tethys, Rings and Shadows Excellent crisp image; separate rings' shadows form a neat pattern of
lines on Saturn. Crescent Tethys shows its clear disk just sun-ward of the
Shadows on the rings as equinox approaches Jagged shadows, alongside that of Mimas, of the rings on the rings.
Shadows almost at equinox
Named after a mythical character from the ancient pagen world, father of Saturn.
Uranus Uranus, ring and its Moon 18
IR: Moons and rings
IR: Moons, rings and clouds
With ring system
Named after the god of the sea.
Crescents of Neptune and Triton Voyager 2's passing view
Neptune and Triton from Palomar
Southern Hemisphere Composite view from Voyager 2, passing over the south pole.
Neptune's Weather Pretty blue and green, with a smudge of red-yellow
The late great dark spot In 1989, Voyager 2 saw this giant storm with 24 Mm/s winds; but it
Southern springtime in Blue
Heavy Blue Giant
High cirrus clouds
One day, a year after discovery
Rubble Some planets have moons (also called satellites) trapped in orbit around
them; and there are assorted other stray lumps of matter floating around the
Better known as The Moon, Earth's constant companion, always
keeping the same face
towards Earth. Its unprotected surface, bombarded by cosmic
rays, shines brightly in γ-rays, brighter by
far than The Sun.
Twenty full moons May 2005 to Dec 2006, showing size variation and libration
Lunar close-up Moon Mare and Montes
Earth-lit Moon, Pleiades Crescent moon over-exposed
to show dark
side by Earth-light, with Pleiades
The parts we never see from Earth
Apollo 11 panorama by East Crater
Bay of rainbows
Lunar close-up from Apollo 17, 1972; Eratosthenes and Copernicus craters.
Panorama with Shorty crater Taurus-Littrow valley, moon rover and impressive crater, from the last
human visit to the Moon, Apollo 17.
Man, Boulder Apollo 17 astronaut Harrison Schmitt beside a boulder in the
Copernicus Crater in 1966–1967 93 km wide, as seen from the Lunar Orbiter reconnaissance missions
Orange So near horizon its light is reddened; complete with a red flash at
its lower edge.
N Polar Ice
S Polar Ice
S Polar Ice by neutron-mapping
Largest Impact Crater
Illusory X of craters As the Sun rises, as seen from the Moon, it illuminates crater rims
before their floors, revealing height variations.
A microscopic lunar spherule
Lunar seismography since 1969
South polar shading
Sunrise shadow of Tycho's central peak Lunar eclipses
The Earth's shadow comprises, as one moves away from the Sun, a slowly narrowing
cone of total darkness, where Earth hides all of the Sun, within a slowly
widening cone of partial darkness, where at least some of the Sun is
hidden. Selene's diameter is less than that of either, at the distance of her
orbit, so she easilly fits into the shadow, when her path happens to take her
through it. When the whole of the moon is inside the cone of total darkness,
it's a total eclipse of the moon; when otherwise at least partially within the
cone of partial darkness, it's a partial eclipse.
Twelve lunar eclipses, 2006 to 2008
In visible light
Lunar peep-show Sequence of images of Selene sliding through Earth's shadow during a
Lingering Lunar Eclipse
Moon eclipsed red
Time-lapse lunar eclipse And similar from
the South Pole.
Kalamalka time-lapse … and how
Aristarchus estimated the
distance to the Moon.
Eclipse Moon Trail Long exposure, showing the Moon pass through Earth's shadow.
Eclipsed Moon rising Over a house in Huddersfield
Blue Moon eclipse
Winter solstice eclipse … preceded by
an anticipation of
its sky context; followed by a composite showing
the setting eclipse.
With Milky Way as back-drop
With lightning in the foreground Martian
Mars has two natural mooons, both suspected of being captured asteroids, plus
a variable population of man-made visitors.
Stickney Crater, on Phobos
Phobos Dust Hip Deep on Phobos
Doomed Phobos About 5.8 Mm
Mars, orbitting in under 8 hours. Phobos's North
and South poles Close-ups from Mars
Deimos Tiny by the standards of moons, only 15 km (c. 9 miles) across.
Deimos close-up Viking 2 picture, from 18 miles close.
Deimos from MRO Asteroid
Stray lumps of rock in roughly circular orbits about the Sun are known
planets; those which orbit (mostly) closer than Jupiter are known
the ones caught at Jupiter's Lagrange points (leading and trailing Jupiter by
turn/6) are known as Trojans; those orbiting (mostly) between Jupiter and
Neptune are known as Centaurs. Beyond Neptune, there's a zone known as the
Kuiper belt (sometimes: Edgeworth-Kuiper belt) in which many similar bodies
orbit; including Pluto, king of the minor planets (though not actually the
them). The asteroids
of the inner solar system attract plenty of attention, now that we've
realised how close some of them come to hitting
Dog-Bone Asteroid 216, Kleopatra, between Mars and Jupiter.
Eros craters and boulders
With regolith in the craters Asteroid 433 close-up; 40×14×14 km, visited by NEAR
Shoemaker, whose eventual terrain map has been used to produce
Vesta Second largest, half a Mm across. Old telescopic views are now
superseded by images from the robotic Dawn mission's visit, 2011.
Vesta height map False colour representation of Vesta.
Ida and Dactyl Little Dactyl's a mile across (looks less to me); Ida's 36 miles long,
14 across and lumpy.
NEAR 253 Mathilde 60 km across, with at least one 20 km crater that's about 10 km deep.
Colour-enhanced, main-belt asteroid; about 11 miles long.
Sylvia, Romulus and Remus First observed triple asteroid; 380 km Sylvia; 710 km, 33 hr orbit for
7 km Remus; 1360 km, 87.6 hr orbit for 18 km Romulus. Rhea Sylvia was the
P/2010 A2 Looking like a comet-tail, this is suspected of being the residue of a
collision between asteroids.
Visitor gallery A gallery of the asteroids and comets visited by our space-craft, to
date, to mark the occasion of ESA's Rosetta's fly-by of 21 Lutetia, the
largest in the gallery.
Itokawa An Earth-crossing asteroid visited by Japan's Hayabusa probe (2005 to
The Approach Successive views, in-bound, 2005/September
Hayabusa's shadow Two months later, in orbit; Itokawa is 300 m across
No Craters Rubble and slush with no visible cratering.
Ceres and Vesta
Ceres, first and largest
(933 km in diameter), filled a gap in the Titius-Bode sequence: start with 0
and 0.3, then double at each subsequent step to get 0.6, 1.2 and so on; add
0.4 to each entry in that sequence; you now have 0.4, 0.7, 1.0, 1.6, 2.8, 5.2,
10.0, 19.6; which are respectably close to the orbital radii of the planets
out to Uranus (measured as multiples of Earth's orbital radius), save for the
entry between Mars (1.52296 ≅ 1.5) and Jupiter (5.1998 ≅ 5.2). Once
this coincidence had been noticed, astronomers went looking for a planet
orbitting at the missing radius – after the satisfying success
of finding Ceres (on
the first day of the nineteenth century, in an orbit with radius 2.77 times as
big as Earth's), they were a little surprised to find it was (rather small
– Pallas, Vesta
and Juno showed
up soon after. Jovial
The moons of Jupiter caused quite a stir when Galileo first noticed
them. More recently, they've proven even more
seen from closer range.
Inner Moons Metis, Adrastea, Amalthea and Thebe; all in the electromagnetic storm
within Io's orbit.
Io Hot, sulphurous and volcanic, it
resembles the golden snitch from a game of
quiddich, but the yellow colour is due to sulphur, not gold.
Tvashtar's eruption Seen by New Horizons, passing on its way to Pluto
In shadow Io lit by aurora and volcanic plumes in Jove's electromagnetic
maelstrom, seen while passing through that giant's shadow.
Vulcanism Pele region before and after a Pillan Patera eruption.
In triplicate Three Galileo images, plain and digitally enhanced, showing colour
Ra Patera erupts Crescent Io seen by Galileo, with blue volcanic plume at its edge.
Icy on the outside, but might there be life in oceans within ?
Full face Galileo using natural colour
Ice shapes Cracks and Ridges on Europa
Ice Cusps possible evidence of tectonic activity
Ice jigsaw Oceans under Europa's surface? Following day shows ice rafts, this
one shows the ice sheet with lots of cracks.
Impact Impact crater over-laid with cracks.
Close-up Galileo: 560 Kilometers Above Europa, showing lumpy terrain
Cracked ice plains
The largest moon in the Solar System – bigger than Mercury and Pluto.
Messy surface Mysterious Features on Ganymede – a non-crater circular arc,
cut by a linear crater chain, beside a broad linear feature.
Crater chain Crater Chain on Ganymede, left by a Torn Comet.
Minerals Galileo orbiter's mineral analysis.
Contrast-enhanced mosaic Also available
Callisto A jagged ice-field with possible sub-surface ocean
A dark face, full of spots Too cool to re-arrange its surface and hide the impact scars left by
everything that's hit it.
Enhanced Showing big crater Valhalla; previous day has same view in true
Big cliff Saturnine
Saturn has plenty of moons plus a beautiful system of rings. It also has an
artificial satellite, called Cassini, which has sent us back lots of
Prometheus knocks stripes off the F-ring
Pandora 80 km wide, partner to
together they shepherd the F ring
and Janus Twin moons with orbital radii within 50 km, 91 Mm above Saturn's
cloud-tops, doing a perpetual dance – swapping orbits every four years
and sheperding the A ring. Epimetheus is about 115 km across; Janus is about
190 km across, with a shape reminiscent of a potato.
Epimetheus and Janus Seen together beside the rings
Mimas' nipple Mimas (
not the death star from Star Wars) seen (c/o
Cassini) half-face, with its (130 km span) huge nippled
crater, Herschel, facing us on the
Herschel crater close-up
Anthe and its arc
Enceladus and Mimas passing Rhea
Enceladus An ice-ball with clean surface, stripey in places, and geysers.
Creating the E ring
Saturn, rings and Enceladus Saturnian Moon and Rings
Spots and stripes
Fountain of Ice Enceladus crescent view, showing what
tiger stripes are up
Crescent plums over Saturn's strata
Tiger strips from 1.7 Mm close
Labtayt Sulci Vast canyon, about 1 km deep.
Fresh tiger stripes
Telesto and Calypso Sharing an orbit; Telesto
Tethys's forward Lagrange point, Calypso
its lagging one.
Smooth Telesto 24 km across in Tethys's forward Lagrange.
Unusually smooth Calypso Only 20 km long, irregular in shape.
The Great Basin on Tethys
Tethys and rings With its Great Basin making Tethys look disturbingly like
death star from Star Wars.
Tethys: cratered ice cliffs
Cassini fly-by view from 32 Mm away; ball
(mostly) of ice is c. 1 Mm in diameter.
Dione and Helene
Another Lagrange pair, just outside the E ring. Dione is mostly water ice, but
has enough rock to make it perceptibly heavy. Icy Polydeuces occupies the rear
Helene Lagrange companion ahead of Dione; now available
Dione, rings and their shadow
Dione White streaks and craters
Dione close-up Showing scratches and craters; a 23 km wide patch seen from 4.5 Mm
Dione's bright cliffs cut craters
Dione and Titan
Rhea Second largest, tidally locked, more heavilly cratered on leading
Rhea up close as seen by Cassini from 620 km away
Rhea's Great White Spot
Rhea and the rings
Through rings, with Janus
Titan Saturn's largest moon (second largest in the Solar system, behind
Jupiter's Ganymede) has an atmosphere, so Cassini took Huygens to visit Titan
and get us some more detailed information. Most of the following are images
Cassini itself took, using radar to see through the atmosphere, during its
many fly-bys. Titan's surface temperature
93 K and its atmosphere is dominated by methane.
Is it a cloud ? Is it a volcano ? Titan has an odd spot which stays in the same place …
Cryovolcano Dome-shaped feature resembling volcano, may be with ice-CH4-NH3
slurry for lava.
Shore-line Radar image from Cassini; Titan appears to
Lake District Suspected
methane lakes seen in radar
Tethis behind Titan
Hyperion close-up Sponge Moon, caver's delight ? Tidal effects make its spin chaotic.
Iapetus One side is so dark its discoverer, Cassini, noted that it was only
visible when on one side of Saturn.
The dark side of Iapetus
Close-up of Iapetus' equatorial ridge
Phoebe Irregular dark surface, retrograde orbit, low density – suspect
Kuiper belt refugee, now in Saturn's orbit. Looks just like the Clangers'
home planet ;^)
Much remains to be seen of Uranus and its environs; but we know it also has
Miranda's rugged face Chevron, and Alonso. Miranda also has
canyon perhaps 12 miles deep – wow !
Ariel: Valley World
Titania Uranus' largest moon.
Oberon with crater Hamlet in plain view
Oberon: Impact World Neptunous
Neptune is so far away we can't see its moons very well; it has (at least)
six, plus a system of rings.
Despina and her shadow
Proteus So dark we didn't notice it until Voyager 2 visited; and almost big
enough for its gravity to make it spherical, but not quite.
Some of the dirty snow-balls that populate the outer reaches of the solar
system get disturbed into highly eccentric orbits that bring them sporadically
into the inner solar system; this exposes them to The Sun's heat, causing them
to partially evaporate, thereby releasing loose dust and debris, which reflect
the Sun's light and produce a spectacular bright appearance, often visible to
the naked eye from Earth. These transient visitors are known as comets (the
word comes from a latin word for hair, comes) and give
photographers an excuse to capture them against often beautiful
Comet Ikeya-Zhang tail wriggles
Comet Holmes Late in 2007, as it was heading
away from the sun, Comet
17P/Holmes surprised everyone by flaring up and growing to
be bigger than the Sun, but with only
the faintest of tails. It made
a fine sight for several
Comet Breaks Up Comet SWAN
brightens and flares
Comet, planetary nebula and galaxy Fragment C of 73P/Schwassmann-Wachmann 3; passing almost directly in
front of the Ring Nebula (M57), and faint spiral galaxy IC 1296.
Hyakutake, the Great Comet of 1996
Night sky with Hale-Bopp Hale-Bopp from Indian Cove in California's Joshua Tree National
Forest. Nice fore-ground rocks, sky full of stars plus double-tailed
Comet McNaught over Catalonia January 2007 saw the brightest comet since 1965, C/2006 P1, providing
STEREO's SECCHI instrument's first subject
Comet McNaught (C/2006 P1) also managed to
arrive just as some new equipment was deployed to study The Sun and things
passing near it.
McNaught's tail After passing the sun, C/2006
showed a particularly splendid tail,
including striae (i.e. stripes).
Green Lulin's two tails
SOHO 6 taking after Icarus A sungrazer comet, destroyed by getting too close to the Sun.
Lulin and Saturn near opposition Notably, Lulin goes round the Sun the opposite way to the planets, so
moved unusually fast across the sky.
C/2009 R1 McNaught Same discoverer, new comet; came into easy view in June 2010.
comet Hartley 2 (103/P Hartley) and pac-man
EPOXI's close-up of Hartley 2 A later mission for the same craft as Deep
revealing gas jets and snow-balls.
Hartley 2 between M46 and M47
Pojmanski (C/2006 A1) in colour Tempel
1 This comet was chosen as the target for the Deep Impact probe,
which deliberately crashed into it, to help us learn more about cometary
structure. Images below are of the comet's solid nucleus.
Landscape close-up before Deep Impact
Hubble's view of the impact Composite of close-up views Used
as illustration for a terse write-up of what the probe revealed.
Follow-up visit, a few years later The Outer Reaches
When first seen, Pluto was classified as a planet. Its apparent size had to be
revised downwards (it's actually smaller than several moons of other planets,
including our own) when it was discovered that its apparent diameter and the
amount of light apparently from it arose from its having a relatively large
moon, Charon. It's since emerged that plenty of other bodies are in orbits
similar to its (eccentric, tilted from the ecliptic and in a resonance with
Neptune's orbit), constituting the inner class
of (TNOs). The orbits of these, in turn, overlap with those
objects a second
population of similar bodies in roughly circular orbits; this population
matches fairly well with what Edgeworth and Kuiper postulated to explain the
origin of comets. Beyond this (but again overlapping its orbits) are further
bodies in elliptical orbits, reaching far out towards the cold depths of
inter-stellar space. Among these three populations, folk have found assorted
bodies of size comparable with, and bigger than, Pluto. With Pluto thus
revealed as merely a prominent member of one of several populations of
TNOs, it was downgraded from planet
status in 2006, just as Ceres had been when it turned out to be merely the
biggest of another population
asteroids. TNOs are generally dirty snow-balls; the comets, above, are ones
that have been dislodged into unusual orbits.
Pluto's Charon-wards face
Suspected extra moons for Pluto
Pluto, Charon, Nix, Hydra and P4
Pluto, the frozen
(minor) planet, and its companions.
2001 KX76 Comparing Pluto's size to other known Kuiper belt objects.
Quaoar Another minor planet in the Kuiper belt.
2003 UB, now known as 313 Eris Twice as distant as Pluto – and bigger, thereby forcing the
issue of what criteria a body must satisfy to deserve to be deemed a
planet. Once that was resolved, in August of 2006, Pluto was a dwarf planet
and the body which had provoked its
given the name Eris (goddess
of discord –
warmonger, the cause of conflict, the source of competitive rivalry –
not of chaos, as some prefer to think). Apparently she
moon, Dysnomia (goddess of lawlessness; perhaps those who identify Eris
with chaos should credit her with the virtue of disobedience). Eris was,
before being officially named, nick-named Zena, after a character (in the
eponymous television program) played by Lucy Lawless.
New Horizons sets off With so much to learn about the outer reaches, a probe is now on its
way to study them from close-up. Launched in January 2006 and faster than any
probe before it, it'll still take until 2015 to reach Pluto.
Views from home
Distant things seen alongside the veiwer's context.
Mars lines up with Pollux and Castor
Lunar crepuscular rays
Pleasant Bay's night sky
Moon The simple, regular wanderer and those that dance behind her.
System Rise Solar System Rising Over Fire Island, with Light-house at dawn as
Jupiter watches Selene embrace Venus
Brisbane Water reflects Jove and Venus with
Jove in Selene's halo, over Spain's San
Salt Lake Horizon Utah's Great Salt Lake at sun-set, with human fore-ground and
Mercury, Venus, Saturn and Selene
Goddard remembered Mars, Venus and Earth-lit Moon seen through trees
Full moon, Jupiter and a church tower
Moon and Mars over pre-dawn Mullica
Hyakutake, Venus, Orion and Pond Missouri night view
Selene de-occluding Saturn
Almodovar, Moon and Venus
Moon eclipses Venus
Moon and Venus over Mauna Kea storm clouds
Moon and Venus: Sun-set evening view
Crescents of Moon And Venus
Crescents of Selene and the Morning Star
Crescents of Venus and Selene In the day-time sky; or
Twilight calm with Moon and Venus
Sunset with crescent Moon and Mercury
Mercury, crescent Moon and Earth-lit dark side
Mercury, Venus and Moon
Mt. Wilson 60″ centenary
Jupiter, Venus, Selene and pollution over Los
Moon, Mercury, Jupiter and Mars over Tuggerah
Crescent Moon, Pleiades and Mercury framed by clouds
Birds, clouds, crescent Moon and Venus
Harvest moon and Jupiter in opposition over a
Hungarian ruin at equinox
Crescents of Venus and Selene
Mars emerges from occultation
Seen from the world she helps keep stable.
Moonset over clouds From the space shuttle Columbia, in 1990
Antarctic Moon … setting in the North
Poseidon's temple Moonrise,
Cape Sounion, Greece, with a
nice classical ruin in the foreground.
In Mauna Kea's shadow
Fullest of 2009 over Breil-sur-Roya
Crestent over Istanbul
Eiffel lunar eclipse
Lick's full moon, rising
Moon River Crescent moon over the St Lawrence River
Full Moon over French castle
Full Moon, Lake, and Leonid
Crescent Moon from low-Earth orbit
Autumn Moon Ansel Adams' famous 'photo re-created; from Glacier Point, Yosemite.
About to occult the Pleiades
As back-drop to a passing air-craft
Above Mt. Teide's triangular shadow
Wandering stars and the world that wonders about them.
Comet McNaught over Chile
Comet Holmes amidst the trees of Breil-sur-Roya in southern France, with a satellite pasing
Turkish dawn with Venus and comet
Jupiter at Ephesus
Planets Over Stonehenge
Laguna Beach planet triangle Moon, Saturn and Venus
Venus and Jupiter at dawn
Venus, Jupiter and Milky Way over Chile
Mars and Orion over Monument Valley
A geminid over Monument Valley
Crowded sky mirrored Reflections on the Inner Solar System – Moon, Venus and Mercury
low in the sky over a still lake at dusk.
Mars over Nevada Valley of Fire in Nevada, aesthetic rocks in fore-ground, Mars in the
Jupiter and Milky Way over the Turkish coast
Venus, Mercury and a wind-pump
Venus, Mercury and Nôtre Dame Cathedral,
Saturn, Mars and Leo over Kurdistan
Mercury, Regulus, Venus, Mars and Saturn over
Venus, Mars and Saturn over Iranian sand
Jupiter and Uranus together at opposition
Venus rising under Mesa Arch Trajectories
Repeated or prolonged exposures to show the path of Sun, Moon, planet
Oak and star-trails over Haute-Provence
Star Trails Over Vienna A bit of digital trickery to turn star-trail arcs into full circles,
over a Viennese castle.
Mercury's arc at sunset
Clifton Suspension Bridge Solargraph
Solar Analemma over ancient Nemea, or over Athens'
Maidens; or the other way round (possibly different time of
day ?) over the temple of Olympian Zeus at
Athens; and a morning one from New Jersey.
Tutulemma: eclipse analemma Solar analemma in which one frame, which supplies the background, was a
total eclipse – and Venus was visible in it.
Lunar Analemma Moon at nearly-same place in sky (at intervals of 1 day + 51 minutes)
over the course of a month.
Retrograde Mars As Earth passes between Mars and the Sun, over-taking Mars, Mars
travel backwards in Earth's sky.
Evening space-chase Tracks of the ISS and shuttle on their way to a rendez-vous.
Venus and Mercury: eight evenings
Star trails over Mudgeee, NSW
Venus analemma 44 superposed images at constant time of day, at five day intervals,
showing Venus's movement in the evening sky.
Star trails over a viking church ruin, with
Full moon set over Rio Starry skies
Distant lights against homely fore-grounds.
Big Dipper Castle
Horizon to horizon
The Big Picture
Moonlit mountain and stars
Clouds near and far
Orion over Mt. Nemrut's ancient sculptures
Antipodean sky With
space debris burning up on re-entry
in the fore-ground.
Sky Panorama over blue Lake Salda
Spring sky over Hirsau Abbey
Constellations over Brazil
Pastoral summer night in Iran
Orion: scene from two hemispheres
All around the shrunken Earth
Jupiter and Uranus in opposition at equinox
Sirius, Orion, Pleiades and a frosted leaf Orion over Irish snow
Milky Way It spans the sky, so the horizon is its context.
Over Creux du Van
Over Utah rocks
Death Valley Darkness
Reflected in one of Ontario's lakes
Mysian Olympic view
Alborz mountains panorama
Arcing over Mauna Kea
From Mauna Kea, arcing along the horizon
From inside a cave, False Kiva
Patagonia, comet McNaught and three galaxies
Over Uluru with a fire-ball meteor
Over Devil's Tower
Over South Dakota's Badlands
From Mt. Whitney
Arcing gracefully over the Cascade range
Over Ignaçu Falls
Over Alamut fortress
Over Pulpit Rock
With perseid and Jupiter, over ruins
Loch Ard Gorge's shadows in
Fish-eye view, through trees
Over the erupting Piton de la Fournaise
Over Teide volcano, Tenerife
From Venus to eclipsed Selene … arching over the Very Large Telescope in Chile.
Milky Way and Zodiacal Light
Contrasted, from Tenerife
Side-by-side, from Laguna Verde
Over-arching, from Tenerife
Double-act, over Namibia Atmospheric
The atomosphere is crucial to our existence and survival: it also produces really pretty optical effects.
Sundogs and 22 degree halo
Sun halo over Cambodia
Noctilucent Clouds After sun-set on ground, high clouds still lit.
Whole-sky noctilucent cloud display
Circum-horizontal arc a.k.a.
Kiwi lenticular cloud
Mt. Rainier's lenticular clouds
Morning Glory Clouds
Michigan Sun-set A Seemingly Square Sun, setting over Lake Michigan
Sun Pillar in Red and Violet Accompanied by pretty pink clouds, over mountains, reflected in Lake
Sun pillar over North Carolina
Sun pillar over Wyoming
Light pillars over Latvian street lamps
Misty morning vineyard sky Taken in Northern California's
Valley of the Moon, showing the
Belt of Venus nice and clearly.
A triple sun-rise
Roll cloud over Uruguay
Lunar fog-bow Like
a rainbow in fog, but from Selene's
light, with Mars on the horizon.
Atmospheric layers in profile Approaching shuttle seen from ISS, with troposphere, stratosphere and
mesosphere in silhouette as background.
Labelled layers at sun-set
Many morning glory hoops
The Belt of Venus over Uluru
Moon rising in Mauna Kea's shadow
Halos and sun-dogs over Stockholm
Meteors and Meteorites When little bits of space rubble hit the atmosphere, they burn up in
quick streaks of light. Comets fill their orbits with dust and grit, which
manifest as meteor showers when Earth passes through a comet's orbit.
Sky Full of Leonids
Meteor Colours Fireball, Smoke Trail, Meteor Storm
Raining Perseids Milky Way with meteors streaking out of Perseus.
Quadrantid and faint Comet Lulin
Fireball meteor A chance picture – along with news of a metre-scale
2008 TC3, discovered less than a day
before its destruction on hitting Earth's atmosphere; it was very intensely
studied in that brief interval.
1972 Earth-grazer's daytime fire-ball
Lyrid meteor, Milky Way
Sky-map of meteor origins
Geminid Fireball over the Mojave Desert
Lightning, perseid, Jove, pleiades and
Geminid over the Mojave desert
Earth's magnetic field focuses the solar wind onto the poles, creating pretty
glowiness where it hits the outermost wisps of the atmosphere.
Comet and Aurora Ikeya-Zhang and spring aurora over Alaska
Starry Aurora Alaskan Aurora, through which we can see stars
Alaskan lake view
Auroras over Lake
Aurora over Iowa
Ice-reflected alongside Selene
ISS Aurora Green aurora seen from ISS, which orbits so low it passes through them
Aurora with alleged Perseids
Perseid Aurora … and
another in the same green,
pink, purple sky.
Purple Aurora over Norway
Aurora Above Looking up an aurora's multi-coloured skirts !
Aurora Astern Australis from
Aurora with Mars and Pleiades Green, purple and white fore-ground, spotty back-ground.
Floral Aurora Corona
With bonus Geminid fireball over Kvaløya
Green Aurora Australis Ribbon From the ISS, c. 350 km above the Indian Ocean.
Over Prelude Lake, Canada
Over moon-lit Alaska
Yellowknife aurora series
Over Icesland Mostly Harmless
… at least according to the
Hitch-Hiker's Guide to the Galaxy.
Somewhere over the rainbow
Blue Jet Lightning
Red Sprite Lightning
Lightning over Athens
Mt. Etna spits magma 50 km across, 3 km high, basalt; big and active
Anak Krakatau Slowly building an island.
Tungurahua Erupts Ecuador's volcano, with a roughly ninety year cycle
Forest Fire Elk stand in river as fire sweeps by
Himalayan night sky
Fire in the sky down below Sunrise Over Kilimanjaro – or, rather, under the cloud layer
Eclipse pair 2008 August's two eclipses;
moon covering the sun and
moon in Earth's shadow; each with a watery foreground.
Earth Rise from Apollo 8, 1968/
First Earth-rise In 1966, Lunar Orbiter 1 looked back across the moon at Earth. Only
black-and-white, but the detailed fore-ground Moon makes up for the blurry
Earth. And it was first. Better still, it's
been restored, bringing out more
Equinox sunset over Lake Balaton, Hungary
Full moon behind Old Faithful
Annapurna and star trails
Swill pine, Mars and neighbours
Eyjafjallajökull halts Atlantic air
Laser zaps galactic centre
Fossil nuclear reactors at Oklo, Gabon
Supercell thunderstorm over Montana Surreal Swiss Sunrise with Moon and
Venus, as backdrop to a mountain valley blanketed in cloud underlit by the
Stuff humanity has made, or considered making, to send off-planet.
July 1950; Bumper 2 Cape Canaveral's first launch, a modified V-2 with second stage to
reach 400 km altitude, but not orbit.
Sputnik 1 First to orbit; 1957, October 4th
Von Braun's Wheel
Lunokhod Russian Moon Robot
from 1970; 0.9 tonnes of
machinery that explored Mare Imbrium.
The Voyagers' Message Both copies of which are
of the solar system.
Armstrong climbing down a ladder
Eagle rising, homeward bound from the moon Apollo 11's Lunar Module, on its way back to the Command Module,
heading home from its historic mission, with Earth on the horizon. See also
stereoscopic anaglyph from a few moments before
High Chair Manned Maneuvering Unit in low Earth orbit.
Hubble … and again,
Mir, Moon and Clouds
Descent To Jupiter Artist's impression of Galileo's probe parchuting down through the
STS 123: Endeavour's night-time launch
Kepler's launch The start of
mission to search for habitable Earth-like planets of nearby stars.
Ares 1-X test flight
Incoming Soyuz, from the ISS
Apollo 13's damage
Delta IV Heavy launch Rockets capable of lifting 23 tonnes into low Earth orbit.
STS 135: Atlantis ends the shuttle era
ISS Orbiting the Earth once every 90 minutes or so at an altitude of
Space Station is
Dextre the Magnificent A robotic care-taker for the ISS.
Dextre preparing for Kibo
ISS over Caspian and over
the Ionian Sea, between Italy and
Seen from Earth, 2008/Dec/27
With Earth as back-drop, 2010/Feb
Seen out of its own window, 2010/Apr
Silhouetted against the Sun, with Atlantis,
2010/May/16 Final visits by
EVA to unload and
a final re-entry. Art and Tech
Stuff our species has gotten up to.
Frizion Illume Ice crystals twisting polarized light
Twinkling colours A spinning camera captures colour variation in Regulus's twinkling and
contrasts it with Mars's steady red.
A Sonic Boom
Stars and Mount Rushmore
Mt. Erebus + TIGER's Balloon
ERAST: Daedalus Defied Pathfinder Plus – 270 kg of solar panel and reflector, spanning
nearly 30 m, flew up to 24.7 km altitude.
Before 'henge Nabta: Older than Stonehenge, 6000 years old, Sahara.
Newgrange solstice In County Meath, Ireland; 5 k yr old, so older than Stonehenge.
Dunhuang Star Atlas, c. 650 CE
Very Large Array … of 27 Radio Telescopes, each 25 metres across, in New Mexico.
Starry Night A painting by Vincent van Gogh, 1889;
another, over the Rhône from 1888.
7 k yr old cave painting and Milky Way
Spiral Jetty in the Great Salt Lake
The Antikythera Orrery
Kona Galaxy Garden
The flying Spaghetti Monster
I maintain there is much more wonder in science than in pseudoscience. And in
addition, to whatever measure this term has any meaning, science has the
additional virtue, and it is not an inconsiderable one, of being
Carl Sagan, The Burden Of Skepticism, The
Skeptical Inquirer, Vol. 12, Fall 87