NGC 3991 NED02

NGC 3991 NED02 is a spiral galaxy in the constellation Ursa Major about 152 million ly from Earth. It spans roughly 37,000 ly, about 37% of our Milky Way's width. The light reaching us tonight left it about 152 million years ago.

Because its light is 152 million ly from home, you are seeing NGC 3991 NED02 as it looked roughly 152 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).