Scientists from the Rehovot-based Weizmann Institute have participated in the first-ever study of the world’s largest exploding star and discovered the after effects: a black hole. The observation was carried out in coordination with colleagues at San Diego State University. The observed star was 50 times larger than the sun, and after the explosion, the star simply collapsed and left a black hole in the universe that was so dense that light could not pass through it. Weismann Prof. Avishav Gal-Yam and San Diego Prof. Douglas Leonard’s conclusion supports the theory that stars even hundreds of times larger than the sun also end up as black holes. They were able to predict the end of the start’s existence by studying its energy from birth and until their fuel depletes and leaves an iron core that collapses from intense heat. The explosion occurs in a huge “supernova” flash that releases more energy in several days than the sun does over many years. The blast is bright enough that it can be seen from the Earth even in daylight. Just before the explosion, the size of the star shrinks from thousands of miles to only six miles but with material that is as heavy as the entire Earth. The star that the professors recently observed is one to five times the size of the previously-observed exploding star.
