NGC 4004

NGC 4004 is an irregular galaxy in the constellation Leo about 156 million ly from Earth. It spans roughly 53,000 ly, about 53% of our Milky Way's width. It is receding from us at about 3,377 km/s.

Because its light is 156 million ly from home, you are seeing NGC 4004 as it looked roughly 156 million years ago. The photons left before that much of history had passed, and are only now reaching us. This distance is estimated from the galaxy's redshift, so the lookback time is approximate.

Source: structural data (position, morphology, brightness, redshift) from OpenNGC (CC BY-SA). Recession velocity from RC3 (de Vaucouleurs et al. 1991, via NASA/HEASARC, public domain). Distance computed by gravityfinder from redshift via Hubble's law (H0 = 70 km/s/Mpc).