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Star's Black Hole Encounter Puts Einstein's Theory of Gravity To the Test (sciencemag.org)
An anonymous reader quotes a report from Science Magazine: For more than 20 years, a team of astronomers has tracked a single star whipping around the supermassive black hole at the center of our galaxy at up to 25 million kilometers per hour, or 3% of the speed of light. Now, the team says the close encounter has put Albert Einstein's theory of gravity to its most rigorous test yet for massive objects, with the light from the star stretched in a way not prescribed by Newtonian gravity. In a study announced today, the team says it has detected a distinctive indicator of Einstein's general theory of relativity called "gravitational redshift," in which the star's light loses energy because of the black hole's intense gravity. The star, called S2, is unremarkable apart from a highly elliptical orbit that takes it within 20 billion kilometers, or 17 light-hours, of the Milky Way's central black hole -- closer than any other known star. A team led by Reinhard Genzel at the Max Planck Institute for Extraterrestrial Physics (MPE) in Garching, Germany, has been tracking S2 since the 1990s, first with the European Southern Observatory's (ESO's) 3.6-meter New Technology Telescope in Chile's Atacama Desert and later with ESO's Very Large Telescope (VLT), made up of four 8-meter instruments. Ghez's team at UCLA also began to observe the star around the same time with the twin 10-meter Keck telescopes in Hawaii. In a paper published today in Astronomy & Astrophysics, Genzel's group reports seeing the combined action of the relativistic effects, with the black hole's gravity redshifting S2's radial velocity by 200 kilometers per second, a small fraction of its overall speed. The results match closely with the predictions of relativity and are inconsistent with Newtonian gravity.
Because this story also arrived here yesterday. At least this post has more info.
Not long ago, it was impossible to see stars at this distance. Now adaptive optics have improved the resolution so much that they are able to track stars at the center of the galaxy. This is through all the intervening dust and closer stars obstructing the view. I have trouble getting a good image of Saturn due to atmospheric turbulence, and these guys are imaging the center of the galaxy. Well done.
That Newtonian gravity is imprecise is already well known, milions of people who use GPS, Glonass or Galileo already use the general relativity calculations in practice. It is far more interesting to know how the results compare to alternative theories of gravity, like for example Verlinde's: https://en.wikipedia.org/wiki/...
Actually it's closer to a peak of 240k/s if you look at table 3. Though the gravitational gradient must not be too large given the massive size of the black hole in question here, it would be amazing If it were possible to see a close pass stretch a star into a ribbon and watch as it is torn apart. As it is the star must deform considerably under those enormous fields.
Where's the goatse guy now that he could be topical at least once?
We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
My own experience has been the opposite. When I do a test or look for data to prove/test my own ideas, no matter how hard I try I can't completely get away from confirmation bias. I suppose if I tried hard enough, I could end up with reverse confirmation bias - designing the experiment and looking at the data in a way designed to prove the opposite. That's still bias.
When I look at results from people who were NOT trying to test my pet theory, who were collecting the data for an unrelated reason, I can both find surprising facts I wasn't looking for and have a degree of confidence that the experiment and data weren't subconsciously (or conciously) biased, because the people collecting the data weren't even interested in the question I'm considering.
Having said all of that, isolating variables is a real thing.