Nav: Home

A test of general relativity at the galaxy's center suggests Einstein's theory still holds

July 25, 2019

In a detailed study of a star orbiting the supermassive black hole at the center of our Galaxy, researchers report that Einstein's theory of general relativity (GR) accurately describes the behavior of light struggling to escape the gravity around this massive structure. The researchers' analysis involved detecting an effect known as "gravitational redshift" in the light emitted by a star closely orbiting the supermassive black hole, as the star was at its closest point to the blackhole in its 16-year orbit. While a similar analysis was conducted by the GRAVITY collaboration last year, here, Tuan Do, Andrea Ghez and colleagues report novel spectra data and expanded analyses. Even as general relativity has been tested in relatively weak gravitational fields, such as those on Earth and in the Solar System, it had not - before last year - been tested around a black hole as big as the one at our Galaxy's center, known as Sagittarius A*. Observations of the stars rapidly orbiting this supermassive black hole would create a method for GR to be evaluated in an extreme gravitational environment. Do, Ghez and colleagues analyzed new observations of the star S0-2 as it made its closest approach to the enormous black hole in 2018. These data were combined with measurements Ghez and her team have made over the last 24 years. The analysis revealed the gravitational redshift, which occurs when light is stretched to longer wavelengths by the gravitational field around the black hole, thereby shifting it towards the red part of the spectrum. The results are consistent with general relativity and substantially favor the theory over Newtonian gravity, which cannot account for the observed redshift. The findings are a "transformational change in our understanding about not only the existence of supermassive blackholes but the physics and astrophysics of black holes," says Ghez in a related video.
-end-


American Association for the Advancement of Science

Related Black Hole Articles:

Scientists make waves with black hole research
Scientists at the University of Nottingham have made a significant leap forward in understanding the workings of one of the mysteries of the universe.
Collapsing star gives birth to a black hole
Astronomers have watched as a massive, dying star was likely reborn as a black hole.
When helium behaves like a black hole
A team of scientists has discovered that a law controlling the bizarre behavior of black holes out in space -- is also true for cold helium atoms that can be studied in laboratories.
Star in closest orbit ever seen around black hole
Astronomers have found evidence of a star that whips around a likely black hole twice an hour.
Tail of stray black hole hiding in the Milky Way
By analyzing the gas motion of an extraordinarily fast-moving cosmic cloud in a corner of the Milky Way, Astronomers found hints of a wandering black hole hidden in the cloud.
Hubble gazes into a black hole of puzzling lightness
The beautiful spiral galaxy visible in the center of the image is known as RX J1140.1+0307, a galaxy in the Virgo constellation imaged by the NASA/ESA Hubble Space Telescope, and it presents an interesting puzzle.
Clandestine black hole may represent new population
Astronomers have combined data from NASA's Chandra X-ray Observatory, the Hubble Space Telescope and the National Science Foundation's Karl G.
When will a neutron star collapse to a black hole?
Astrophysicists from Goethe-University Frankfurt have found a simple formula for the maximum mass of a rotating neutron star and hence answered a question that had been open for decades.
Behemoth black hole found in an unlikely place
Astronomers have uncovered a near-record breaking supermassive black hole, weighing 17 billion suns, in an unlikely place: in the center of a galaxy in a sparsely populated area of the universe.
Behemoth black hole found in an unlikely place
Astronomers have uncovered one of the biggest supermassive black holes, with the mass of 17 billion Suns, in an unlikely place: the centre of a galaxy that lies in a quiet backwater of the Universe.

Related Black Hole Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Anthropomorphic
Do animals grieve? Do they have language or consciousness? For a long time, scientists resisted the urge to look for human qualities in animals. This hour, TED speakers explore how that is changing. Guests include biological anthropologist Barbara King, dolphin researcher Denise Herzing, primatologist Frans de Waal, and ecologist Carl Safina.
Now Playing: Science for the People

#SB2 2019 Science Birthday Minisode: Mary Golda Ross
Our second annual Science Birthday is here, and this year we celebrate the wonderful Mary Golda Ross, born 9 August 1908. She died in 2008 at age 99, but left a lasting mark on the science of rocketry and space exploration as an early woman in engineering, and one of the first Native Americans in engineering. Join Rachelle and Bethany for this very special birthday minisode celebrating Mary and her achievements. Thanks to our Patreons who make this show possible! Read more about Mary G. Ross: Interview with Mary Ross on Lash Publications International, by Laurel Sheppard Meet Mary Golda...