Image: Infrared image at the top of the page from NASA’s Spitzer Space Telescope shows the expanding remains of Kepler’s supernova, first seen 400 years ago by sky watchers, including famous astronomer Johannes Kepler.
Astronomers have calculated the odds that, sometime during the next 50 years, a supernova occurring in our home galaxy will be visible from Earth, calculating the odds to be nearly 100 percent that such a supernova would be visible to telescopes in the form of infrared radiation. A new study suggests that they have a solid chance of doing something that’s never been done before: detect a supernova fast enough to witness what happens at the very beginning of a star’s demise.
“We see all these stars go supernova in other galaxies, and we don’t fully understand how it happens. We think we know, we say we know, but that’s not actually 100 percent true,” said Christopher Kochanek, professor of astronomy at Ohio State and the Ohio Eminent Scholar in Observational Cosmology."Today, technologies have advanced to the point that we can learn enormously more about supernovae if we can catch the next one in our galaxy and study it with all our available tools."
Astronomers now have sensitive detectors for neutrinos (particles emitted from the core of a collapsing star) and gravitational waves (created by the vibrations of the star’s core) which can find any supernova occurring in our galaxy. The question is whether we can actually see light from the supernova because we live in a galaxy filled with dust—soot particles that Kochanek likened to those seen in diesel truck exhaust—that absorb the light and might hide a supernova from our view.
“Every few days, we have the chance to observe supernovae happening outside of our galaxy,” said team member Scott Adams. “But there’s only so much you can learn from those, whereas a galactic supernova would show us so much more. Our neutrino detectors and gravitational wave detectors are only sensitive enough to take measurements inside our galaxy, where we believe that a supernova happens only once or twice a century.”
For those of us who would hope to see a Milky Way supernova with our own eyes, however, the chances are lower and depend on our latitude on Earth. The last time it happened was in 1604, when Johannes Kepler spotted one some 20,000 light years away in the constellation Ophiuchus. He was in northern Italy at the time.
With only one or two happening a century, the chance of a Milky Way supernova is small, but it would be a tragedy to miss it, and this work is designed to improve the chances of being ready for the scientific event of a lifetime,” Beacom concluded. The odds that astronomers would spy a truly dazzling supernova—like the Kepler that outshone all other stars in the sky—at only around 5 percent.
The Daily Galaxy via The Ohio State University