Moving

Drag

orbit around the point in the middle

Scroll

zoom; each step is a constant factor, so AU to Gpc takes seconds

Right-drag

pan

Click

anything for its values, how they were measured and where they come from

/

search by name (SIMBAD and NED)

The clock

The clock is observer time: the moment light arrives at Earth, in UTC. Stars move by their measured motions, planets, asteroids and satellites are computed for the instant, and supernovae, bursts and mergers appear on the day their light arrived. The timeline is logarithmic: the Big Bang at the left, the present near the right, marks where events arrived.

Distances

Every distance says how it was measured. Galaxies placed by redshift use a flat ΛCDM universe; the Hubble constant setting under Galaxies rescales them (67.66 from Planck, 73.0 from the local distance ladder: the Hubble tension). Distances measured without a redshift do not move.

Layers

Data credits and licences