NGC 4504

NGC 4504 is a spiral galaxy in the constellation Virgo about 46 million ly from Earth. It spans roughly 43,000 ly, about 43% of our Milky Way's width. The light reaching us tonight left it about 46 million years ago.

Because its light is 46 million ly from home, you are seeing NGC 4504 as it looked roughly 46 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).