Friday, October 05, 2012

A star screaming through space around a black hole

I like science, and write about it for The Register, but there’s not always room for everything that gets my attention. So from time to time, I’m going to throw science stuff here as well.

And this looks like a pretty cool place to start: a star orbiting black hole near the middle of the Milky Way that completes its orbit far quicker than Pluto orbits the Sun.

While Pluto needs nearly 250 years to complete a circuit of the Sun, this star (S0-102) is whipping around the black hole it orbits in just over 11 years.

This is exciting to astronomers, because most stars’ orbits are too slow for us to hope for a complete observation. The solar system takes more than 200 million years to circuit the Milky Way, for example.

By comparison, astronomers will be able to see this star complete two orbits in just 23 years.

So what? you might ask.

While Einstein’s theory of general relativity is very robust, some of its predictions are difficult to test: you need data, and some of that data is hard to come by. For example, it predicts that a star in a black hole’s gravity well will be red-shifted; and that its orbit, pulled out of an elliptical orbit, will over time form the kind of flower-shape you might get out of a Spirograph.

Neither of these predictions, however, can be tested if it takes hundreds of years to gather the data.

That’s why instruments like the Thirty Meter Telescope, or TMT (, are on the hunt for stars with high-speed orbits.

Pretty cool, I think!

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