This map shows the position of almost every confirmed supernova known to modern researchers. The map is an equirectangular projection of the night sky in galactic coordinates, showing the entire sky as visible from Earth with our Milky Way galaxy running through the middle. The size of each circle illustrates the relative brightness (as seen from Earth) for each supernovae. The slider on top of the page lets you move through history, exploring when different supernovae were first discovered. Look to the counter in the top right to see what date range is currently shown, and click on any supernova to learn more about it.
A supernova is the explosive death of a star. They occur when a very massive star runs out of fuel for nuclear fusion (a core-collapse supernova) or when a white dwarf star exceeds its stable mass limit (a thermonuclear supernova). Supernovae are incredibly bright due to the radioactive decay of elements like nickel and cobalt but they begin to fade away within a few weeks of explosion. Because most supernovae are incredibly distant they appear dim to us on Earth. To find a new supernova, you must identify one new point of light in the night sky amongst the billions of stars and galaxies that are always visible - it's not easy. With modern technology, however, researchers have gotten pretty good at it. This page includes supernovae.
Of course, this page only shows the supernovae that researchers know about, and it doesn't even show all of them. The map above includes all objects confirmed (usually by spectroscopic observations) to be supernovae and then submitted to the International Astronomical Union (IAU). There are many other objects identified as possible supernovae, by both professional and amateur astronomers, that never get confirmed (for example, this website by David Bishop and the Rochester Academy of Sciences shows both confirmed and unconfirmed supernovae that are bright right now), there are many supernovae that are confirmed by researchers, but never submitted to the IAU (from projects like PanSTARRS, La Silla Quest, and PTF), and of course there are many, many more supernovae that escape detection. Supernovae have been exploding all across the universe for billions of years, but astronomers have only started to really pay attention for the last 100 or so. There are three reliable historical accounts of incredibly bright supernovae from before the 1800's (the oldest is from the year 1054), though of course those ancient astronomers did not know that the bright light they saw in the night sky was a supernova.
Most of the trends and patterns visible in the animation above are due to the methods astronomers use to look for and discover supernovae and are not real trends in supernovae properties. For example, astronomers have identified about the same number of supernovae in the past 10 years as they did in all the years before then, even though the frequency of supernova explosions in the local universe has not changed significantly. Here are a few other interesting trends:
This website was built by Isaac Shivvers, an astrophysics graduate student at UC Berkeley. Feel free to contact me with any questions or comments at ude.yelekreb.ortsa@srevvihsi.
The supernova data behind this site was assembled from the International Astronomical Union's official list of named supernovae. The map is automatically updated with newly-discovered supernovae every week.
The background image of the night sky is courtesy of ESO/S.Brunier, and was produced as part of the European Southern Observatory's GigaGalaxy Zoom project.
© Isaac Shivvers, 2013
Have questions about what you see here, or any trends you've noticed?
Check out the About page for more info!