How close a supernova would have to be to wipe out all life on Earth
Supernovas are created during the last moments of a star's life. These gigantic explosions can wipe out galaxies and the planets inside them. Should we be concerned about one being too close to our Solar System? Following is a transcript of the video.
The cosmos can be a dangerous place for life. About every 50 years a star explodes in our home galaxy, the Milky Way. These powerful eruptions are called supernovae.
They can emit the same energy in a single instant that our sun will generate in over 1 million years. Needless to say, if a supernova goes off close enough life on Earth – as we know it — would perish.
But just how close would one need to be? Astronomers estimate we have a comfort zone of about 50 light-years.
That’s about 27 times the size of our solar system. Any supernova closer than that and — well, you get the idea.
50 light-years may seem like a comfortable distance, but we’re actually in more danger now than the past. Earth is currently moving through a peanut-shaped region of space called the “Local Bubble.” About 10 million years ago, astronomers think a neighborly cluster of stars went supernova, spewing their gaseous guts across the galaxy, which created the Local Bubble.
Usually, the Local Bubble is no cause for concern. But, according to recent estimates, this residual gas could actually magnify the lethal effects of a supernova by increasing the amount of high-energy radiation that reaches Earth. The last time Earth felt the effects of a supernova was about 1.7 to 3.2 million years ago. The explosion took place 325 light-years away — 6.5 times farther than the danger zone — but Earth was still affected.
Some iron from the star’s core reached our planet. You can find it on the ocean floor. There’s no telling when the next nearby supernova will occur. But don’t worry. At their brightest, supernovae can outshine an entire galaxy.
So, at least we’ll see the shock coming before it happens.
This video was originally published on May 31, 2017.