Astronomers predict that the star Eta Carinae will soon undergo a supernova explosion. Although it’s over 7,500 light-years away from Earth, this supermassive star outshined Sirius, the brightest star in the night sky, from 1838 until 1858. However, because it is so far away from Earth, most of the harmful radiation that will be produced when the supernova occurs will disperse in the vacuum of space, with very little of it reaching our solar system. The closest supernova to have occurred near Earth since 1604 was 1987A, but it was still approximately 160,000 light-years away. Scientists expect Earth to receive a substantial burst of radiation from a supernova every 20 million years, enough to affect the atmosphere and the ozone layer. If the supernova occurs close enough to Earth, then life as we know it could be impacted dramatically.
How close does the supernova have to be to Earth to sufficiently impact life? At one hundred light-years and farther, a supernova poses no threat to Earth. Other than observing a bright light in our sky, we would experience no change on Earth. However, at fifty light-years away, a supernova will rip the ozone layer from our planet and destroy our magnetic field. Without a magnetic field, Earth would be bombarded by solar and cosmic radiation, causing a mass extinction of all complex life on the surface of Earth. What if a star one light-year away underwent a supernova? The closest star to us (other than the sun) is the red dwarf Proxima Centauri, which is just over four light years away. Although that star would never undergo a supernova, if in theory a star did so just one light year away from Earth, then not only our planet, but our entire solar system would be obliterated by the supernova’s shockwave.
Given current scientific estimates and predictions, the death of Earth by supernova is extremely unlikely if not impossible in the near future. So you can probably safely cross nearby supernovae off the list of possible threats to our existence on Earth, while being thankful that the ones that will occur in your lifetime will almost all be in galaxies far far away...
- Siqi Yang