Objects

All 123 objects in Cosmic Scale, grouped by type and listed from smallest to largest within each group. Each page carries the object's description, figures and facts as the app shows them, with a link that opens the object in the app.

Every object is drawn at its true size relative to the others. Radii are mean radii from NASA/JPL fact sheets and published measurements; supergiant stars and the largest galaxies are uncertain by tens of percent. For black holes the size is the event horizon; nebulae, galaxies and superclusters are artistic renderings at true size.

Asteroids & comets

• Bennu · Near-Earth asteroid · 490 m across
  Bennu is a rubble-pile asteroid about half a kilometre wide: loose rocks and boulders held together by their own feeble gravity.
• Comet 67P · Churyumov–Gerasimenko · 4.0 km across
  67P/Churyumov–Gerasimenko is a comet shaped like a rubber duck, two lumps joined by a neck.
• Halley's Comet · Periodic comet · 11 km across
  Halley's Comet is the most famous comet of all: the first known to return on a schedule, and the only bright one that does so within a human lifetime.
• Vesta · Protoplanet in the asteroid belt · 525 km across
  Vesta is the second-largest body in the asteroid belt and the brightest asteroid in our sky.

Stellar remnants

• Neutron star · Collapsed stellar core · 22 km across
  When a star far heavier than the Sun runs out of fuel, its core collapses in about a second and the rest of the star explodes as a supernova.
• Sirius B · White dwarf · 11,688 km across
  Sirius B is the burnt-out core of a star that was once more massive than Sirius itself.

Moons

• Deimos · Moon of Mars · 12 km across
  Deimos is the smaller and outer of the two moons of Mars, a lumpy, dusty body barely 12 km across.
• Phobos · Moon of Mars · 22 km across
  Phobos is the larger moon of Mars and orbits closer to its planet than any other moon in the Solar System, only 6,000 km above the surface.
• Mimas · Moon of Saturn · 396 km across
  Mimas is the smallest body in the Solar System still rounded by its own gravity.
• Miranda · Moon of Uranus · 472 km across
  Miranda is the smallest of Uranus's five large moons and one of the strangest-looking worlds known: a patchwork of grooved terrain, giant cliffs and smooth plains, as if it had been shattered and pieced back together.
• Enceladus · Moon of Saturn · 504 km across
  Enceladus hides a global ocean of salty water beneath an icy shell.
• Tethys · Moon of Saturn · 1,062 km across
  Tethys is a mid-sized moon of Saturn made almost entirely of water ice.
• Dione · Moon of Saturn · 1,123 km across
  Dione is an icy moon of Saturn with bright ice cliffs streaking its trailing side.
• Charon · Moon of Pluto · 1,212 km across
  Charon is half the width of Pluto, so the two do not simply orbit one another: they both circle a point in empty space between them, always showing each other the same face.
• Iapetus · Moon of Saturn · 1,469 km across
  Iapetus is Saturn's two-faced moon: its leading side is as dark as coal and its trailing side as bright as snow.
• Oberon · Moon of Uranus · 1,523 km across
  Oberon is the outermost of Uranus's large moons, an old, cratered world of ice and rock.
• Rhea · Moon of Saturn · 1,528 km across
  Rhea is Saturn's second-largest moon, a heavily cratered ball of ice with a little rock.
• Titania · Moon of Uranus · 1,577 km across
  Titania is the largest moon of Uranus, a world of ice and rock split by enormous canyons that may have cracked open as its interior froze and expanded.
• Triton · Moon of Neptune · 2,707 km across
  Triton orbits Neptune backwards, which almost certainly means it did not form there: it is a captured object from the Kuiper Belt, seized by Neptune's gravity.
• Europa · Moon of Jupiter · 3,122 km across
  Beneath Europa's cracked shell of ice lies an ocean holding perhaps twice as much water as every ocean on Earth combined.
• The Moon · Earth's moon · 3,475 km across
  The Moon formed when a Mars-sized body struck the young Earth and the debris pulled itself together in orbit.
• Io · Moon of Jupiter · 3,643 km across
  Io is squeezed between Jupiter's gravity and the pull of the other large moons, and the friction melts its insides.
• Callisto · Moon of Jupiter · 4,821 km across
  Callisto is the most heavily cratered object in the Solar System — a surface so old and so unchanged that it records four billion years of impacts.
• Titan · Moon of Saturn · 5,149 km across
  Titan is the only moon with a thick atmosphere, and the only world besides Earth with liquid on its surface — though its rivers, lakes and rain are methane and ethane, not water.
• Ganymede · Moon of Jupiter · 5,268 km across
  Ganymede is the largest moon in the Solar System — bigger than Mercury — and the only one with a magnetic field of its own, generated by a molten iron core.

Dwarf planets

• Ceres · Dwarf planet · 939 km across
  Ceres is the largest object in the asteroid belt and the only dwarf planet inside Neptune's orbit.
• Sedna · Distant dwarf planet · 1,000 km across
  Sedna is one of the most distant known worlds in the Solar System.
• Quaoar · Dwarf planet · 1,110 km across
  Quaoar is a dwarf planet in the Kuiper belt, about half the size of Pluto.
• Gonggong · Dwarf planet · 1,230 km across
  Gonggong is one of the largest dwarf planets, a reddish world of ice on a long, tilted orbit far beyond Neptune.
• Makemake · Dwarf planet · 1,430 km across
  Makemake is a bright, reddish world of methane ice in the Kuiper Belt, discovered shortly after Easter 2005 and nicknamed 'Easterbunny' before it was named after the creator god of Rapa Nui.
• Haumea · Dwarf planet · 1,560 km across
  Haumea is a dwarf planet beyond Neptune that spins so fast — once every 3.9 hours — that it has been stretched into an egg shape about twice as long as it is wide.
• Eris · Dwarf planet · 2,326 km across
  Eris is slightly smaller than Pluto but noticeably heavier.
• Pluto · Dwarf planet · 2,377 km across
  Pluto was the ninth planet for 76 years, and is now the best-known dwarf planet.

Planets

• Mercury · Planet · 4,879 km across
  Mercury is the smallest planet and the closest to the Sun, with almost no atmosphere to even out its temperature.
• Mars · Planet · 6,779 km across
  Mars is a cold desert with seasons, polar caps and the tallest volcano in the Solar System.
• Venus · Planet · 12,104 km across
  Venus is almost Earth's twin in size, and nothing like it in every other way.
• Earth · Planet · 12,742 km across
  The only world we know that has liquid water on its surface, an oxygen atmosphere and life.
• Neptune · Ice giant · 49,244 km across
  Neptune was found with mathematics before anyone looked: astronomers noticed Uranus was being tugged off course, calculated where the culprit must be, and pointed a telescope there in 1846.
• Uranus · Ice giant · 50,724 km across
  Uranus was the first planet discovered with a telescope, and it is tipped over: its axis lies almost in the plane of its orbit, so it rolls around the Sun on its side.
• Saturn · Gas giant · 116,464 km across
  Saturn's rings are only tens of metres thick but stretch hundreds of thousands of kilometres — countless chunks of nearly pure water ice, from grains to house-sized boulders, each on its own orbit.
• Jupiter · Gas giant · 139,822 km across
  Jupiter has two and a half times the mass of every other planet put together.

Exoplanets

• TRAPPIST-1e · Rocky exoplanet · 11,723 km across
  TRAPPIST-1e is one of seven Earth-sized planets orbiting a small red dwarf 40 light-years away.
• Kepler-452b · Super-Earth · 20,769 km across
  Kepler-452b was announced in 2015 as the closest thing yet to an Earth twin: a slightly larger world orbiting a Sun-like star on a 385-day year, right in the habitable zone.
• 55 Cancri e · Lava super-Earth · 23,955 km across
  55 Cancri e is a super-Earth so close to its star that its year lasts 18 hours and its day side may be an ocean of magma.
• TrES-4b · Puffy hot Jupiter · 250,281 km across
  TrES-4b is a hot Jupiter so puffed up by its star's heat that its density is lower than cork.
• HAT-P-67b · Inflated hot Saturn · 299,219 km across
  HAT-P-67b is one of the largest planets known and one of the least dense — a Saturn-mass world blown up to more than twice Jupiter's width, trailing a vast cloud of escaping helium.

Stars

• TRAPPIST-1 · Red dwarf · 165,855 km across
  TRAPPIST-1 is a cool red dwarf barely larger than Jupiter, and it has seven Earth-sized planets — the largest family of rocky worlds known around one star.
• Proxima Centauri · Red dwarf · 214,554 km across
  Proxima Centauri is the closest star to the Sun, a small red dwarf gravitationally tied to the bright pair of Alpha Centauri.
• Barnard's Star · Red dwarf · 260,192 km across
  Barnard's Star moves across our sky faster than any other star — a tenth of the Moon's width each century.
• Epsilon Eridani · Orange dwarf · 1.0 million km across
  Epsilon Eridani is a young orange dwarf, a little smaller and cooler than the Sun, only 10.5 light-years away.
• Alpha Centauri B · Orange dwarf · 1.2 million km across
  Alpha Centauri B is the slightly smaller, cooler partner in the closest star system to the Sun.
• The Sun · Yellow dwarf · 1.4 million km across
  The Sun is an ordinary yellow dwarf star, and it holds 99.86% of the mass of the Solar System.
• Alpha Centauri A · Yellow star · 1.7 million km across
  Alpha Centauri A is the closest star to the Sun that is genuinely Sun-like: same type, slightly larger and brighter, and about the same age.
• S301 · Star orbiting Sagittarius A* · 2.1 million km across
  S301 is a star a little bigger than the Sun, discovered in 2026 on the tightest known orbit around Sagittarius A*.
• Sirius · White main-sequence star · 2.4 million km across
  Sirius is the brightest star in the night sky, partly because it is genuinely luminous and partly because it is close.
• Vega · White main-sequence star · 3.3 million km across
  Vega was the first star ever photographed and the first to have its spectrum recorded.
• S2 · Star orbiting Sagittarius A* · 8.5 million km across
  S2 is a hot young star orbiting Sagittarius A*, the black hole at the centre of the Milky Way.
• Spica · Blue giant (binary) · 10.4 million km across
  Spica, the brightest star in Virgo, is really two hot blue stars orbiting each other every four days, so close that each is pulled into an egg shape by the other.
• Pollux · Orange giant · 12.6 million km across
  Pollux is the brightest star in Gemini and the closest giant star to the Sun.
• Arcturus · Red giant · 35.3 million km across
  Arcturus is an ageing orange giant and the brightest star in the northern half of the sky.
• Polaris · Yellow supergiant · 52.2 million km across
  Polaris sits almost exactly above Earth's north pole, so it barely moves while the sky turns around it — which made it the navigator's star for centuries.
• R136a1 · Wolf–Rayet star · 59.4 million km across
  R136a1 is the most massive star known: around 200 Suns packed into a Wolf–Rayet star in the Tarantula Nebula.
• Aldebaran · Red giant · 61.4 million km across
  Aldebaran is the red eye of Taurus the Bull, an orange giant that has swollen to 44 times the Sun's width.
• Canopus · Bright giant · 98.8 million km across
  Canopus is the second-brightest star in the night sky and a favourite of spacecraft: its brightness and position make it an excellent reference point for navigation far from Earth.
• Rigel · Blue supergiant · 109.8 million km across
  Rigel is a blue supergiant marking Orion's foot, and one of the most luminous stars visible to the naked eye.
• Deneb · White supergiant · 282.5 million km across
  Deneb marks the tail of Cygnus the Swan and one corner of the Summer Triangle.
• Eta Carinae · Luminous blue variable · 333.9 million km across
  Eta Carinae is one of the most massive and luminous stars in our galaxy, about 5 million times brighter than the Sun.
• Pistol Star · Blue hypergiant · 425.8 million km across
  The Pistol Star is a luminous blue variable near the centre of the galaxy, hidden behind so much dust that it was only found in the 1990s with infrared eyes.
• Rho Cassiopeiae · Yellow hypergiant · 884.9 million km across
  Rho Cassiopeiae is a yellow hypergiant, one of the rarest kinds of star, about half a million times brighter than the Sun; in the Sun's place it would reach into the asteroid belt.
• Antares · Red supergiant · 946.2 million km across
  Antares is the red heart of Scorpius, a supergiant so large that if it replaced the Sun it would swallow the orbit of Mars.
• Betelgeuse · Red supergiant · 1.1 billion km across
  Betelgeuse is the red shoulder of Orion and the most famous star waiting to explode.
• UY Scuti · Red supergiant · 1.3 billion km across
  UY Scuti is a pulsating red supergiant in the constellation Scutum, and for years it topped the lists of the largest known stars.
• Mu Cephei · Red supergiant · 1.4 billion km across
  Mu Cephei is a deep red supergiant that William Herschel called 'a most beautiful garnet colour' — hence its nickname, the Garnet Star.
• RW Cephei · Red hypergiant · 1.5 billion km across
  RW Cephei is a red hypergiant, one of the largest stars known.
• Westerlund 1-26 · Red supergiant · 1.7 billion km across
  Westerlund 1-26 is a red supergiant in Westerlund 1, the most massive young star cluster in the Milky Way.
• HR 5171 A · Yellow hypergiant · 1.8 billion km across
  HR 5171 A is a rare yellow hypergiant, and rarer still for having a companion star so close that the two touch, sharing an envelope of gas.
• VY Canis Majoris · Red hypergiant · 2.0 billion km across
  VY Canis Majoris is a red hypergiant losing mass at a spectacular rate, wrapped in a nebula of its own making.
• KY Cygni · Red supergiant · 2.0 billion km across
  KY Cygni is a red supergiant in Cygnus, one of the largest stars in the Milky Way.
• WOH G64 · Hypergiant · 2.1 billion km across
  WOH G64 is a hypergiant in the Large Magellanic Cloud, wrapped in a thick cocoon of dust it has thrown off.
• Stephenson 2-18 · Red supergiant · 3.0 billion km across
  Stephenson 2-18 is a red supergiant near the star cluster Stephenson 2, and one of the largest stars ever proposed.

Black holes

• Gaia BH1 · Dormant black hole · 57 km across
  Gaia BH1 is the closest known black hole to Earth, found not by any glow but by watching a Sun-like star swing around something invisible.
• Cygnus X-1 · Stellar-mass black hole · 125 km across
  Cygnus X-1 is a black hole of about 21 Suns locked in a 5-day orbit with a blue supergiant star.
• Gaia BH3 · Dormant black hole · 195 km across
  Gaia BH3 is a black hole of 33 Suns found in 2024 from the wobble of a star orbiting it every 11.6 years.
• Sagittarius A* · Supermassive black hole · 25.4 million km across
  Sagittarius A* is the supermassive black hole at the centre of the Milky Way, 26,700 light-years away.
• M87* · Supermassive black hole · 38.4 billion km across
  M87* was the first black hole ever photographed.
• NGC 4889 · Ultramassive black hole · 124.0 billion km across
  NGC 4889 is a giant elliptical galaxy in the Coma Cluster, hosting one of the largest black holes ever weighed: about 21 billion Suns.
• Holmberg 15A* · Ultramassive black hole · 236.2 billion km across
  Holmberg 15A is the brightest galaxy of its cluster, and its centre is strangely empty of stars — the signature of a huge black hole that scattered them away during past galaxy mergers.
• TON 618 · Ultramassive black hole · 389.8 billion km across
  TON 618 is an ultramassive black hole powering a quasar so bright that we can see it from over ten billion light-years away.
• Phoenix A* · Ultramassive black hole · 590.6 billion km across
  Phoenix A* is the black hole at the heart of the Phoenix Cluster, and current estimates put it near 100 billion Suns — possibly the most massive known.

Solar System

• Solar System · The Sun and its planets, out to Neptune · 9.0 billion km across
  The Sun and everything bound to it: eight planets, hundreds of moons, millions of asteroids and comets, all formed 4.6 billion years ago from one collapsing cloud of gas and dust.
• Oort Cloud · Shell of icy bodies around the Sun · 3.16 light-years across
  The Oort Cloud is a vast shell of icy bodies surrounding the Solar System, so far out that passing stars can nudge its members loose.

Nebulae & clusters

• Helix Nebula · Planetary nebula · 5.74 light-years across
  The Helix Nebula is the glowing shell of gas thrown off by a dying Sun-like star.
• Crab Nebula · Supernova remnant · 11 light-years across
  The Crab Nebula is the wreckage of a star that exploded in AD 1054, bright enough to be seen in daylight for three weeks and recorded by Chinese and Japanese astronomers.
• Orion Nebula · Star-forming nebula · 24 light-years across
  The Orion Nebula is the nearest large stellar nursery, a glowing cavern of gas being carved out by the young stars inside it.
• Eagle Nebula · Star-forming nebula · 70 light-years across
  The Eagle Nebula is a cloud of gas and dust where new stars are forming, lit by a young cluster at its centre.
• Pleiades · Open star cluster · 86 light-years across
  The Pleiades, or Seven Sisters, is a cluster of young, hot blue stars — among the nearest to Earth and one of the most obvious to the naked eye.
• Omega Centauri · Globular star cluster · 150 light-years across
  Omega Centauri is the largest globular cluster orbiting the Milky Way: around ten million ancient stars in a ball 150 light-years across.
• Carina Nebula · Star-forming nebula · 460 light-years across
  The Carina Nebula is one of the largest and brightest star-forming clouds in the Milky Way, four times as large as the Orion Nebula.
• Tarantula Nebula · Star-forming nebula · 1,000 light-years across
  The Tarantula Nebula, in the Large Magellanic Cloud, is the largest and most active stellar nursery near us.

Galaxies

• Small Magellanic Cloud · Dwarf irregular galaxy · 18,900 light-years across
  The Small Magellanic Cloud is a dwarf galaxy orbiting the Milky Way, a companion of the Large Magellanic Cloud.
• Large Magellanic Cloud · Irregular satellite galaxy · 32,200 light-years across
  The Large Magellanic Cloud is the Milky Way's biggest companion galaxy, an irregular spiral distorted by our gravity.
• Sombrero Galaxy · Spiral galaxy, seen almost edge-on · 49,000 light-years across
  The Sombrero Galaxy is a spiral seen almost edge-on, with a huge glowing bulge crossed by a dark lane of dust — like a wide-brimmed hat.
• Triangulum Galaxy · Spiral galaxy · 61,100 light-years across
  The Triangulum Galaxy is the third-largest member of the Local Group, after Andromeda and the Milky Way.
• Whirlpool Galaxy · Grand-design spiral galaxy · 76,900 light-years across
  The Whirlpool Galaxy is a classic spiral seen face-on, its arms stirred up by a smaller galaxy, NGC 5195, that is passing behind one of them.
• Milky Way · Barred spiral galaxy · 100,000 light-years across
  Our galaxy: a barred spiral of a few hundred billion stars, with a supermassive black hole at its centre and the Sun about two-thirds of the way out.
• Andromeda Galaxy · Spiral galaxy · 152,000 light-years across
  Andromeda is the nearest large galaxy and the most distant thing most people can see without a telescope.
• Condor Galaxy · Barred spiral galaxy (NGC 6872) · 522,000 light-years across
  The Condor Galaxy, NGC 6872, is one of the largest spiral galaxies known.
• Malin 1 · Giant low-brightness spiral · 650,000 light-years across
  Malin 1 is a giant spiral galaxy so faint that it was only discovered in 1986.
• Hercules A · Radio galaxy · 920,000 light-years across
  Hercules A is a giant elliptical galaxy whose central black hole, about 4 billion Suns, blasts out jets of particles at nearly the speed of light.
• ESO 383-76 · Supergiant elliptical galaxy · 1.8 million light-years across
  ESO 383-76 is a supergiant elliptical galaxy at the heart of the galaxy cluster Abell 3571, in the Shapley Supercluster — the densest gathering of galaxies in our part of the universe.
• IC 1101 · Supergiant elliptical galaxy · 4.0 million light-years across
  IC 1101 sits at the centre of a rich galaxy cluster and is one of the largest galaxies known.
• Alcyoneus · Giant radio galaxy · 16.3 million light-years across
  Alcyoneus is a giant radio galaxy whose jets have inflated two lobes of plasma stretching 16 million light-years end to end — one of the largest single structures made by one galaxy.
• Porphyrion · Largest known black-hole jets · 23.0 million light-years across
  Porphyrion is a pair of jets from a supermassive black hole that stretch 23 million light-years end to end — the largest black-hole jets ever seen, found in 2024 with the LOFAR radio telescope.

Cosmic structures

• Local Group · Our group of 80+ galaxies · 10.0 million light-years across
  The Local Group is our galactic neighbourhood: more than 80 galaxies bound together by gravity, dominated by the Milky Way and Andromeda, with Triangulum a distant third and the rest mostly dwarfs.
• Virgo Cluster · Cluster of galaxies · 14.4 million light-years across
  The Virgo Cluster is the nearest large cluster of galaxies, about 1,300 of them, and the heart of the Virgo Supercluster that contains the Local Group.
• Coma Cluster · Rich cluster of galaxies · 20.0 million light-years across
  The Coma Cluster is a rich cluster of over 1,000 galaxies, most of them ellipticals.
• Virgo Supercluster · Supercluster of galaxy groups · 110.0 million light-years across
  The Virgo Supercluster is the collection of galaxy groups around the Virgo Cluster, with our Local Group sitting out near its edge.
• Shapley Supercluster · The most massive nearby supercluster · 160.0 million light-years across
  The Shapley Supercluster is the largest concentration of galaxies within about a billion light-years: more than 8,000 galaxies in dozens of clusters, with ESO 383-76 among them.
• Boötes Void · Cosmic void · 404.0 million light-years across
  The Boötes Void is an enormous, nearly empty bubble in space about 400 million light-years across.
• Laniakea Supercluster · Our home supercluster · 520.0 million light-years across
  Laniakea was defined in 2014 by mapping how galaxies move rather than where they sit: every galaxy whose flow converges on the same point belongs to it.
• Sloan Great Wall · Wall of galaxies · 1.4 billion light-years across
  The Sloan Great Wall is a vast sheet of galaxies about 1.37 billion light-years long, found in 2003 in the Sloan Digital Sky Survey.
• Hercules–Corona Borealis Great Wall · Largest known structure · 10.0 billion light-years across
  The Hercules–Corona Borealis Great Wall is the largest structure known in the universe: a region about 10 billion light-years long where gamma-ray bursts are unusually common, suggesting a huge concentration of galaxies.
• Observable Universe · Everything we can ever see · 93.0 billion light-years across
  The observable universe is the sphere around us from which light has had time to arrive since the Big Bang.