The incoming radiation would strip our atmosphere of its ozone. Although we’re still not sure about all the ways being in the midst of an exploding star would affect us, we do know that supernovae emit truckloads of high-energy photons such as X-rays and gamma rays. If a supernova occurred close enough, it could be pretty bad news for our planet. A nearby supernova could cause a mass extinction They determined that it was most likely dumped on our planet by a nearby supernova about 2.8 million years ago.Ħ. Using the rate at which 60Fe decays over time, they were able to calculate how long ago it landed on Earth. In 1998, physicists analyzed crusts from the bottom of the ocean and found layers with a surge of 60Fe, a rare radioactive isotope of iron that can be created in copious amounts inside supernovae. So when scientists come across layers of sediment with spikes of radioactive isotopes, they know to investigate whether what they’ve found was spit out by an exploding star. If a supernova occurred close enough to our planet, we’d be sprayed with some of these unstable nuclei. It also provides us with a way to determine if any supernovae have blown up near Earth. This radioactivity is part of what makes supernovae so bright. Some of this radioactivity emits light signals, such as gamma rays, that we can see in space. In addition to forging elements and neutrinos, the nuclear reactions inside of supernovae also cook up radioactive isotopes. Anyone can sign up to be among the first to know that a star's core has collapsed. If more than two experiments observe a burst within 10 seconds, the computer issues an automatic alert to the astronomical community to look out for an exploding star.īut you don’t have to be an expert astronomer to receive an alert. Each detector is programmed to send a datagram to a central computer whenever it sees a burst of neutrinos. SNEWS is a network of neutrino detectors across the world. Scientists watch for that burst of neutrinos using an early warning system called SNEWS. When they do escape, neutrinos carry away 99 percent of the energy of the supernova. But when a star explodes, the center can become so dense that even neutrinos take a little while to escape. Outside of the core of a supernova, it would take a light-year of lead to stop a neutrino. In a 10-second period, a core-collapse supernova will release a burst of more than 10 58 neutrinos, ghostly particles that can travel undisturbed through almost everything in the universe.