Black Holes Take Light For A Spin

Given how weird black holes are, it’s only fitting that researchers have found a screwy way to detect the rotation of these gravitational monsters. Existing telescopes could be equipped with special detectors to record the twist imprinted on light waves that pass near a rapidly spinning black hole, Bo Thidé of the Swedish Institute of Space Physics in Uppsala and his colleagues report online February 13 in Nature Physics.

[atsimg]http://files.abovetopsecret.com/images/member/b3a6541a3b3f.jpg[/atsimg]
Photons emitted near a rotating black hole get a twist, in the form of orbital angular momentum, represented by the spiral-staircase shape. Detecting that pattern, researchers say, will allow astronomers to directly measure a black hole's spin.

Source: Black holes take light for a spin

Thought this was an interesting read. It would be neat to see a black hole through this technique. I can only assume that the picture above is only a representation of what they would expect to see. The article is to be in a March 2011 issue of Science News, and I'm hoping there is more information as to when this can become one step closer to implementing and exploring.

reply to post by cluckerspud


that was a good read, thumbs up

We have known about circular polarization of light for years but this is a novel way to measure the rotation of a black hole.

Similarly, I would expect more Hawking radiation from a rapidly spinning black hole due to the frame dragging effect.

I cannot however concieve of a slow spinning black hole.

The angular momentum of the original star would be conserved in the collapse and, like a ballerina spinning faster as she draws he arms in, the star would spin at incredible angular velocities by the time it had collapsed to something as small as a black hole.

We know that the smallest "starting mass" for a star to become a black hole would be about two to three times the mass of our sun and that this would collapse to produce an event horizon about 9 kilometers in diameter

cool stuff. the artist representation almost reminds me of fractals,
which seem to occur in nature.