Einstein's Theory of General Relativity passes another crucial test

In the center of our Milky Way is a monster. It's called Sagittarius A *, and it's believed to be a supermassive black hole 4 million times heavier than our sun. The gravity produced by Sagittarius A * is so intense that the stars are much more massive than our orbit around the sun at incredible speeds.

One of the stars, called S2, recently passed through the black hole at a speed exceeding 15.5 million miles per hour. It's over 4,300 miles each second, or nearly 3% of the speed of light.

Even cooler: Our telescopes caught S2 digging around the black hole in May. (This happened 26,000 years ago, long before the beginnings of human civilization, but the starlight in that orbit hit our telescopes in May.) And in making these observations, astronomers once again proved the general theory of Albert Einstein. relativity is correct.

Einstein predicted that when the light (such as the light emitted by S2) passed so close to a source of gravity as powerful, it lost some of its energy. In a certain way, the light must struggle to move in the field of intense gravity.

The light is literally stretched into the distortion effects of space-time gravity. And it does not slow down, but it loses some of its energy – measured in frequency of wave length or, as we see, in color. The result is that blue light shifts slightly more red if it is so close to a strong source of gravity.

This is what is called gravitational redshift, and that's exactly what astronomers have observed, and published in the journal Astronomy & Astrophysics

All of this is possible because astronomers can observe stars in orbit around Sagittarius A * in real time. Here is a time frame of 20 years of observations of the Very Large Telescope of the European Space Agency (yes, we actually call it) looking at the stars in orbit around our galactic center. S2 is one of the stars near the center of the image.

And here is a cleaner and illustrated version of these same observations. The orbital path of the star S2 is delimited in yellow.

Einstein's general theory of relativity is now over 100 years old, and scientists have not found any cracks yet. That's why they are turning to the black hole at the center of our galaxy to test the theory. They want to know if Einstein's theory collapses in more and more extreme environments.

And soon, perhaps, we will take a closer look at Sagittarius A *. In April 2017, astronomers collaborated using telescopes around the world to take a photo of the horizon of the supermassive black hole events. The horizon of events is the edge of the black hole, the limit beyond which nothing can escape, even the light. They are still working to sort out the data from the effort, and we still do not know if they captured a clear rendering of the horizon.

It will be extremely exciting if the image is fully developed: the more we know about this supermassive black hole in the center of our galaxy, the more we can test Einstein's theory.

the holes are outrageously cool