The fact that stars explode is kind of awesome, and lots of astronomers, both backyard and professional, spend a lot of time peering at galaxy after galaxy looking for things that flare-up in the night. On average, a galaxy like ours should have one star explode per century, and that means that if you look at 100 galaxies per year, you should see one explosion. If you look at 100 stars a night for a year, you’re going to statistically find a whole lot of explosions.

But sometimes we don’t. There hasn’t been a good supernova in our galaxy since Johannes Kepler’s time. It appears that this may not so much be a lack of exploding stars issue as a lack of visible exploding stars issue.

Some stars just like to explode in the privacy of dust clouds. A new study using data from the retired Spitzer Space Telescope was able to find the warm glow of five supernovae that weren’t visible to telescopes that image things in the same colors our eyes see. They only looked at forty dusty galaxies, and these five supernovae out of forty galaxies was a high enough number to explain why there are so many galaxies that don’t have visible light supernovae and tells us our past estimates on numbers of supernovae were actually pretty good.

So the sky is full of exploding stars, and sometimes they fling out chunks at two million miles per hour, and sometimes they explode where we can’t see them. That’s not scary or anything. Actually, it’s not. The Universe is big, and we aren’t in danger, and it’s kind of awesome that we can understand our universe.

More Information

NASA JPL press release

“A Spitzer survey for dust-obscured supernovae,” Ori D Fox et al., 2021 June 21, Monthly Notices of the Royal Astronomical Society