Supernova of 161,000 B.C. - Closest to Earth with a Glowing Ring 6 Trillion Miles in Diameter

Supernova of 161,000 B.C. -Closest to Earth with a Glowing Ring 6 Trillion Miles in Diameter

While there is, on average, only one supernova per galaxy per century, there is something on the order of 100 billion galaxies in the observable Universe. Taking 10 billion years for the age of the Universe (it's actually 13.7 billion, but stars didn't form for the first few hundred million), Dr. Richard Mushotzky of the NASA Goddard Space Flight Center, derived a figure of 1 billion supernovae per year, or 30 supernovae per second in the observable Universe!