When was the most recent visible supernova?
1 Answer
If by "visible" you mean naked eye visibility, then the answer is SN 1987a. If by visible you mean in a telescope, then they are happening several times a year in distant galaxies.
Explanation:
SN 1987a occurred in the Large Magellanic Cloud (LMC), a dwarf galaxy that orbits the Milky Way. It was visible to the naked eye, but only visible in the southern hemisphere.
But supernovae in other galaxies occur fairly frequently. At least a few times a year a supernova in a relatively nearby galaxy can be seen in an amateur telescope. In much more distant galaxies they can be observed by more powerful telescopes, such as Hubble.
It is estimated that in a galaxy the size of ours, a supernova should occur about once a century, on average, and since we have not seen one in the Milky Way since 1604, it seems we are "due". Of course, it is possible that there has been one or more recent supernovae in our galaxy, but that they happened on the other side of the galactic core, and were blocked by dust and not visible from Earth.
