Speaker 1: Welcome to brain stuff from how stuff Works. Hey, brain stuff,
Speaker 1: it's Christian Sager. Scientists always seem to be finding new
Speaker 1: evidence of Albert Einstein being right. The latest example comes
Speaker 1: from astronomers using the European Southern Observatories very large telescope
Speaker 1: in Chile. Astronomers there have been studying the stars that
Speaker 1: orbit dangerously close to the supermassive black hole in the
Speaker 1: center of our galaxy. To find that you guessed it.
Speaker 1: Einstein's landmark theory of general relativity is holding strong even
Speaker 1: at the doorstep of the most extreme gravitational field in
Speaker 1: our galaxy. Most galaxies are known to have super massive
Speaker 1: black holes lurking in their cores. In our galaxy, the
Speaker 1: Milky Way is no different. Located approximately twenties six thousand
Speaker 1: light years from Earth, our black hole behemoth is called
Speaker 1: Agittarius A, and it has a mass four million times
Speaker 1: that of our Sun. Astrophysicists are hugely interested in black holes,
Speaker 1: as they're the most compact, gravitationally dominant objects known in
Speaker 1: the universe, and therefore an extreme test for relativity. By
Speaker 1: tracking the motion of stars orbiting close to Sagittarius A,
Speaker 1: a team of German and Czech astronomers have analyzed twenty
Speaker 1: years of observations made by the Very Large Telescope and
Speaker 1: other telescopes using a new technique that pinpoints the positions
Speaker 1: of these stars. One of the stars, called S two
Speaker 1: orbits Sagittarius A every sixteen years and zooms very close
Speaker 1: to the black hole, around four times the distance between
Speaker 1: Neptune and our Sun. Because of its racetrack orbit deep
Speaker 1: inside the black holes gravitational well S two is treated
Speaker 1: as a natural relativity probe into this mysterious strong gravity environment.
Speaker 1: By precisely measuring its motion around the black hole, the
Speaker 1: researchers could compare its orbit with predictions laid out by
Speaker 1: classical Newtonian dynamics, and they found that the star's actual
Speaker 1: orbit deviated from Newtonian predictions exactly as predicted by Einstein's
Speaker 1: general relativity, although the effect was slight. Here's a quick
Speaker 1: example of Einsteinian gravity at work. If you have a
Speaker 1: massive object, it will bend spacetime, like the famous example
Speaker 1: of the bowling ball suspended on a rubber sheet. If
Speaker 1: another object travels past the massive object, the curvature of
Speaker 1: space time will deflect its direction of motion like a
Speaker 1: marble rolling past the bowling ball. Now in two thousand
Speaker 1: and eighteen, S two will swoop to its closest point
Speaker 1: in its orbit around Sagittarius A, and astronomers using the
Speaker 1: Very Large Telescope are preparing a new instrument to get
Speaker 1: an even more precise view of the extreme environment surrounding
Speaker 1: the black hole, called gravity and that's gravity in all caps.
Speaker 1: The instrument is installed on the Very Large Telescopes Interferometer,
Speaker 1: and astronomers not only predict that it will get an
Speaker 1: even more precise gauge on Einstein's general relativity, it might
Speaker 1: even detect deviations away from relativity, possibly hinting at new
Speaker 1: physics beyond relativity. Today's episode was written by Ian O'Neill,
Speaker 1: produced by Dylan Fagan, and for more on this and
Speaker 1: other topics, don't forget to visit how Stuff Works dot com.