plate 5 · the observable universe
the last zoom. this is everything we can in principle see: a sphere 93 billion light-years across, centered — by definition, not by importance — on us. at this scale nothing exists but the cosmic web: filaments of dark matter and galaxies draining into knots, wrapped around voids hundreds of millions of light-years empty.
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each column of this map is about 1.3 billion light-years. the pattern is statistical, not surveyed — it is drawn by the zel’dovich approximation, the same first-order collapse that grew the real web out of quantum noise: start with the almost perfectly smooth universe the CMB shows, displace matter along its initial gravity, and sheets, filaments and clusters fold out on their own. ~2 trillion galaxies live in this sphere, ~10^23 stars, ~10^80 atoms.
you the cmb
+--------|------|--------|--------------|--------|----------------|
z=0.5 z=1 z=2 z=6 z=14.4
redshift vs comoving distance, 0 to 45.4 Gly
the sphere is 93 Gly wide despite being 13.8 Gyr old because space itself has stretched while the light traveled. the ruler shows how lopsided lookback is: half the sphere’s volume, as we see it, lies beyond z~20 — light that left before the first galaxies existed. and the map is already slipping away: space between us and most of it grows faster than light crosses it, so about 95% of the galaxies we can see we can never reach, even in principle, even at lightspeed. the observable universe is mostly a museum.