Supermassive black holes are largest ever discovered
Astronomers have located the two biggest black holes ever found, each one billions of times more massive than our sun. Observations of these supermassive cosmic objects will give scientists clues on how black holes and galaxies form and evolve, especially in the earliest parts of the universe.
The galaxy NGC 3842, around 320m light years from Earth in the constellation of Leo, has a black hole at its centre with a mass of around 9.7bn suns. An even bigger black hole with a mass of around 21bn suns exists at the heart of galaxy NGC 4889, the brightest galaxy in the Coma cluster, around 336m light years from Earth.
These two newly-discovered supermassive black holes were found by analysing data from the Hubble Space Telescope and two of the biggest ground-based telescopes in the world, the Gemini North and Keck 2 facilities in Hawaii. The work, led by Douglas O Richstone of the department of astronomy at the University of Michigan, Ann Arbor, is published this week in Nature. Until now, the biggest recorded black hole was the one at the centre of the giant elliptical galaxy Messier 87, measuring 6.3bn suns.
Black holes are a one-way ticket to mystery, a place where known physics seems to break down and the space we all familiar with becomes supremely strange. They begin as massive stars (at least six times the mass of our sun) and, after billions of years of shining they collapse in on themselves into a singularity, a point smaller than the full-stop at the end of this sentence.
Albert Einstein's general theory of relativity predicts that, if matter is compressed into a small enough space, the resulting gravity gets so strong that nothing nearby can escape the pull. The boundary of the region where the gravity of a collapsed star beats every other force around is called the event horizon. Pass this point, and there is no coming back, not even for particles of light..
