Gamma Ray Bursts (GRBs) are the most powerful explosions in the universe, fact. They are caused when a massive Star (much bigger than our own Sun) explodes by collapsing in on itself, probably producing a Neutron Star or a massive Black Hole. The result is that a huge amount of energy, in the form of Gamma Rays, X-Rays etc are produced, killing everything in its path for many light-years.
If a GRB does hit Earth, the chances it will cause everything living thing death, a bit like a mass extinction which caused the demise of the Dinosaurs. Now researchers have found the probability of a GRB did indeed hit our Earth way back in the 8th century, and here’s how they know this..
Now published in the acclaimed Royal Astronomical Society journals, researchers have confirmed by studying both very old cedar trees in Japan and ancient ice-cores in Antarctica, have confirmed that rare radioactive isotopes have been detected, notably beryllium-10 and carbon-14. These isotopes are produced when the huge energy of the gamma-rays hit our Earth’s atmosphere and react with ozone and other elements, causing these uncommon radioactive particles, probably in the middle ages, around AD 774 and AD 775.
Little is known about GRBs, however scientist say that at least one GRB is detected (by a star going supernova) once a day in the sky, however our Earth will need to be totally aligned with the narrow beam ‘jet’ of the energy of the GRB to cause damage, and apparently, our Earth would need to be within say around 100 light years or so for massive damage to our Earth to be done. Luckily, possible supernova candidate stars that meet this criteria are many thousands of light years distant. So, we should probably be more worried about an Asteroid or Comet impact than GRBs, like Asteroid 2012 DA14 that will be within its closet approach on Friday, 15th February 2013.
Need to know more about Gamma Ray Bursts? Check this great YouTube video below for what may (and might) just happen to Earth.