The mathematics of general relativity can use this mass to predict a very precise size of the dark emptiness, or shadow, where light can't escape. M87* is a supermassive black hole tipping the cosmic scales at 6.5 billion times the mass of the Sun. Since the effect is a gravitational one, the size of the region can be predicted under general relativity. This means no light can shine from a black hole. This shadow is the dark region in the centre of the swirling mass of material, defined by the event horizon - the point at which even light speed is insufficient to attain escape velocity of the black hole's gravitational pull. When scientists achieved, for the first time, the image of a black hole's shadow and a ring of hot material swirling around it, it gave us new ways to test general relativity.
![blackhole chan blackhole chan](https://i.pinimg.com/originals/42/ed/7a/42ed7a8d20278e96c3b9a8bec26097dd.jpg)
We really squeezed down the space of possible modifications." "We found that whatever the correct theory is, it can't be significantly different from general relativity when it comes to black holes. "We expect a complete theory of gravity to be different from general relativity, but there are many ways one can modify it," explained astrophysicist Dimitrios Psaltis of the University of Arizona. So any proposed modifications to current theories that attempt to do that, while failing to be consistent with what we see in real life, should get the chop.
![blackhole chan blackhole chan](https://cdn.donmai.us/sample/5f/a9/sample-5fa90c6fec4378338b1fd5242ee90b20.jpg)
The goal is a unified theory that describes all of the forces in the same manner.
![blackhole chan blackhole chan](https://i.pinimg.com/736x/00/86/3f/00863f6560bd54a1479edea9c08a794d.jpg)
This has led scientists to look for modifications and even alternatives to general relativity. While general relativity is great for predicting and understanding gravitational interactions, it's mathematically incompatible with quantum mechanics the rules that help us model non-gravitational interactions between objects. Yes, it's M87*, the Universe's most photogenic black hole, and the Event Horizon Telescope collaboration has probed the region around it to make general relativity 500 times more robust, incredibly enough. Now, the supermassive black hole at the heart of a galaxy 55 million light-years away has provided relativity with its most stringent test yet.