Black Hole Spin
Scientists at Durham University (UK) have discovered a new way to measure the spin of ginormous black holes. According to the study, this could improve our understanding of how our galaxies are getting bigger; I have always wondered why a lot of the galaxies swirl and grow. A team of astronomers found a black hole that is ten million times the size of our Sun in the center of a spiral galaxy that is about 500 million light years away from Earth. This black hole has been feeding off the materials in the disc of the galaxy which may explain its enormous size.
The data collected allowed the astronomers to measure the distance of the disc from the black hole. Distance depends on how fast the black hole’s spin is, a faster black hole’s spin pulls the disc closer, and by measuring the distance of the disc, they are able to predict the speed of the spin. The scientists agree that this could help in understanding how galaxies grow over a span of billions of years.
(Two New Blue Developments in Our Galaxy)
Almost all galaxies contain black holes. They shoot out extremely hot particles that prevent gases in the galaxy itself from cooling, therefore inhibiting the growth of new stars. The jets of energy that black holes shoot out could be linked to why black holes spin. Unless the matter is close to the black hole, it is difficult to measure spin, since the power of the black hole does not reach to further matter. The odd thing about black holes, according to Professor Chris Done, is that the black hole spin may affect the nature of the whole galaxy.
We know the black hole in the centre of each galaxy is linked to the galaxy as a whole, which is strange because black holes are tiny in relation to the size of a galaxy. This would be like something the size of a large boulder (10m), influencing something the size of the Earth.
When a black hole spins, it drags particles from the accretion disc. The more particles it drags, the faster it is able to spin. Measuring the distance between the two leads to the possibility of measuring a black hole’s spin.
(New Plausible Theory of Black Holes: Gateways to Other Universes)
Sources:
http://simple.wikipedia.org/wiki/Accretion_disc
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