Cosmology
A Journey Through the Universe
Every star and galaxy here is a real measurement. Leave the planets for 45,000 stars catalogued by Hipparcos, visit nebulae and black holes, see the Milky Way from outside, cross to Andromeda, fly through 900,000 galaxies strung into a cosmic web, and keep going past the quasars to the glow of the Big Bang, 46 billion light-years away.
Jump to a scale
Dragging
naked eye: 6deep
Layers
Numbers
Target from Earth—
Its light left it—
You are from the Sun—
Width of the view—
Target looks like (mag)—
Date—
Flying
- W A S D or the arrow keys move you, Q and E go down and up; hold Shift to go faster. Speed follows the scale you are looking at.
- Right-drag, or drag with two fingers, slides the view sideways.
- Scroll or pinch to zoom; click a label to pick it, double-click to fly there.
Data sources
- Stars: HYG v4.0 database (Hipparcos, Yale Bright Star, Gliese), D. Nash / astronexus, CC BY-SA 4.0.
- Planets: JPL approximate Keplerian elements (Standish), valid 1800–2050.
- Milky Way: spiral arms from the maser parallaxes of Reid et al. (2019), ApJ 885, 131; long bar after Wegg et al. (2015). The galaxy is drawn as a model on that skeleton.
- The sky seen from the Solar System: the Milky Way panorama by ESO/S. Brunier (CC BY 4.0).
- Nebulae, clusters and black holes: positions and sizes from the literature (Gaia for the dormant black holes); their pictures are drawn, not photographed.
- Local Group: A. McConnachie (2012), AJ 144, 4, via VizieR.
- Galaxies: 2MASS Redshift Survey, Huchra et al. (2012); SDSS DR18 spectroscopic galaxies (z < 0.2); 6dF Galaxy Survey DR3, Jones et al. (2009). Distances from redshift.
- Quasars: SDSS DR16Q, Lyke et al. (2020), via VizieR; a 6% sample plus every quasar above z = 5.
- Microwave background: WMAP 9-year ILC map, NASA / WMAP Science Team.
- Distances from redshift use Planck 2018: H0 = 67.7 km/s/Mpc, Ωm = 0.311.
What to observe
- Neptune's orbit is 60 AU across. Pull back a little and the nearest star, Proxima Centauri, is still 4,500 times farther than that: the Sun becomes one point among many.
- Every star in the catalogue sits inside a bubble a few thousand light-years wide, on the Orion Spurbetween the Sagittarius and Perseus arms, 26,000 light-years from the centre.
- The arms are where stars are born. Visit the Orion Nebula, 1,300 light-years away, or the Crab Nebula, the wreck of a star that exploded in 1054 and was seen from Earth in daylight.
- The nearest known black hole, Gaia BH1, is only 1,560 light-years away and gives off no light at all: Gaia found it from the wobble of the star that orbits it. At the centre of the galaxy sitsSagittarius A*, 4.3 million times the Sun’s mass.
- Andromeda is 2.5 million light-years away: the light reaching you tonight left it before there were humans.
- Fly into the survey: galaxies gather into walls and filaments around empty voids, the cosmic web. The two wedges are the SDSS and 6dF fields; the gap between them is the band of sky our own galaxy's dust hides.
- Past the quasars, whose light left them up to 13 billion years ago, the sky ends in themicrowave background, light from 380,000 years after the Big Bang. Space grew while it travelled, so that wall is now 46 billion light-years away, not 13.8.
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