Big Bang Monday: Know Your Black Hole

Stephen Hawking was wrong. He bet Kip Thorne at CalTech that Cygnus X-1 did not contain a black hole. Now we know for sure, with scientists having done a complete description.

Here’s how

Though Cygnus X-1 has been studied intensely since its discovery, previous attempts to measure its mass and spin suffered from lack of a precise measurement of its distance from Earth. Reid led a team that used the National Science Foundation’s Very Long Baseline Array (VLBA), a continent-wide radio-telescope system, to make a direct trigonometric measurement of the distance. Their VLBA observations provided a distance of 6070 light-years, while previous estimates had ranged from 5800-7800 light-years.

Armed with the new, precise distance measurement, scientists using the Chandra X-Ray Observatory, the Rossi X-Ray Timing Explorer, the Advanced Satellite for Cosmology and Astrophysics, and visible-light observations made over more than two decades, calculated that the black hole in Cygnus X-1 is nearly 15 times more massive than our Sun and is spinning more than 800 times per second.

“This new information gives us strong clues about how the black hole was born, what it weighed and how fast it was spinning,” Reid said. “Getting a good measurement of the distance was crucial,” Reid added.

“We now know that Cygnus X-1 is one of the most massive stellar black holes in the Milky Way,” said Jerry Orosz, of San Diego State University. “It’s spinning as fast as any black hole we’ve ever seen,” he added.

In addition to measuring the distance, the VLBA observations, made during 2009 and 2010, also measured Cygnus X-1’s movement through our Galaxy. That movement, the scientists, said, is too slow for the black hole to have been produced by a supernova explosion. Such an explosion would have given the object a “kick” to a much higher speed.

That top image would make a really good, big print.


One Comment

  • Roman Tytla says:

    Black holes are the most mysterious celestial objects out there next to dark matter. I don’t care how smart our physicists are. They got to be saying to themselves, “WTF”!

    Love to hear about how scientists obtain their data. Seems like these days the data and images are from multiple sources. It’s great that the latest technology enables us to combine the data in a seamless way. This image of the Helix Nebula is a combined image using both the Hubble and Spitzer Space Telescopes. It’s one of my favorites. The shape is eerily similar to a human eye. Perhaps God’s eye?

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