NGC 4142

NGC 4142 is a barred spiral galaxy in the constellation Ursa Major about 54 million ly from Earth. It spans roughly 27,000 ly, about 27% of our Milky Way's width. The light reaching us tonight left it about 54 million years ago.

Because its light is 54 million ly from home, you are seeing NGC 4142 as it looked roughly 54 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).