NGC 3878

NGC 3878 is an elliptical galaxy in the constellation Ursa Major about 464 million ly from Earth. It spans roughly 81,000 ly, about 81% of our Milky Way's width. The light reaching us tonight left it about 464 million years ago.

Because its light is 464 million ly from home, you are seeing NGC 3878 as it looked roughly 464 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). Distance computed by gravityfinder from redshift via Hubble's law (H0 = 70 km/s/Mpc).