What is a Kilonova?
Credit: Hubble
NASA astronomers have found an intense cosmic event called a “kilonova.” A kilonova is an explosion so powerful that it’s 1000 times stronger than a normal supernova. To help put this in some perspective think about this. The amount of energy a Sun (like the size of our own) produces in its 10 billion life time equals to the amount of energy an average supernova produces. Still not helping? Well think about the amount of energy of the atomic bomb Little Boy outputs (the one dropped on Hiroshima) which is 15 kilotons (6 x 1013 joules) of TNT. During the cold war the United States developed a hydrogen bomb with a max theoretical yield of 25 megatons or 1015 joules. To equal that of a supernova you would need about 10 trillion of the most destructive hydrogen bombs.
Now that your brain is barely hanging on let’s move away from the intensity of that perspective and talk about the kilonova in more detail. Like we stated before a kilonova is 1000 times stronger than an average supernova. Scientists have predicted an event like this occurring in the universe but it was never observed…until now. This discovery could also lead to more information on how heavier elements like gold and platinum originated. The definitive evidence comes from Hubbles observation in the infrared spectrum of a fireball afterglow effect that happened after a gamma ray burst was fired.
Diving in a little more astronomers predict that when there are two dense neutron stars orbiting each other something interesting happens. The binary system emits gravitational radiation and small ripples in the fabric of space-time. The energy is pushed by the waves and causes the two stars to be pulled in closer together. In the final milliseconds, as the two stars merge, the death spiral kicks out highly radioactive material. The material heats up, expands and releases a burst of light. This kilonova lasts for about a week and emits the same amount of energy every seconds as our Sun does every few years. The galaxy where this kilonova was found is approximately 4 billion light years away. This discovery leads us with two points to take away. The first is understanding the origin of heavier elements and the second is observing the mergers of compact objects that emit gravitational waves. These gravitational waves were predicted by Albert Einstein but there were no observations of them. The hunt for kilonovas is on and leaves us to be closer on solving another one of the universe’s mysteries.