NGC 4642

NGC 4642 is a barred spiral galaxy in the constellation Virgo about 123 million ly from Earth. It spans roughly 56,000 ly, about 56% of our Milky Way's width. The light reaching us tonight left it about 123 million years ago.

Because its light is 123 million ly from home, you are seeing NGC 4642 as it looked roughly 123 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).