A new supernova has been discovered in a galaxy far, far away: On the 6th May, astronomers in California captured an image of a star dying in another galaxy, a supernova. In a galaxy 52 million light years away, in the constellation of Virgo a star has reached the end of its life and resulted in the incredibly bright, super-powerful and largest type of explosion that humans have ever seen.
Stars live for an incredibly long period of time, compared to the life of a human for example. The size of a star depends on its life span but a star like our Sun will live on average for 10 billion years. So, given that enormous amount of time, you might think it’s incredibly rare to see the death of a star, but it’s quite the contrary. We would expect to observe a supernova every year in distant galaxies due to number of them we can observe from the Earth and the vast number of stars they contain. In a galaxy like the Milky Way it is estimated that there are over 100 billion stars, so given these huge numbers we should expect to see a star explode every 100 years in our galaxy, but because we can observe hundreds of galaxies using telescopes we can see supernovae in other galaxies much more often.
There are two main types of supernova, the first occurs when a white dwarf star steals so much matter from a nearby star that it causes it to explode! The second type of supernova occurs at the end of a single star’s lifetime. As the star runs out of fuel, some of its mass flows into its core. Eventually, the core is so dense that it cannot resist its own gravitational force. The core collapses, which results in the giant explosion of a supernova. When the star explodes, it fires elements and remains into space. Many of the elements we find here on Earth are made in the core of stars, this includes the iron in our blood and the calcium in our bones, we really are made from stars. These elements travel on to form new stars, planets and everything else in the universe.
The earliest possible recorded supernova, known as HB9, could have been viewed and recorded by unknown Indian observers in 4500 BC, but the most well-known and widely observed is the SN 1054 event which created the spectacular Crab Nebula in Taurus the Bull, this is not visible with the naked eye but an object made famous by spectacular images taken by the Hubble Space Telescope.
This new supernova was discovered by the team at the Zwicky Transient Facility (ZTF) in California, the facility specialises in discovering new luminous objects like supernova throughout the universe. The object lies in a galaxy called M61 which is around 52 million light years away from the Earth. This means although we are seeing this violent star death now, but it actually occurred 52 million years ago. This is because light travels at a finite speed of 300 million meters per second so it takes time for light to travel these enormous distances.
During our next aurora season at the Aurora Borealis Observatory starting in August 2020, we are investing in telescopes to add to the fantastic experiences we can offer our guests during their northern lights holidays. Maybe whilst taking a break from watching the incredible aurora borealis dancing above their heads, one of our guests will be able to observe a star exploding in another galaxy millions of light years away! And maybe spot a new supernova.