A black hole distorts the image of a disk of dust and gas around it, courtesy of the special effects team for the film Interstellar.

A black hole distorts the image of a disk of dust and gas around it, courtesy of the special effects team for the film Interstellar.

© CLASSICAL AND QUANTUM GRAVITY, 2015 (REPRODUCED BY PERMISSION OF IOP PUBLISHING)

Feature: Testing Einstein's theory in the galaxy's toughest neighborhood

Einstein’s general theory of relativity turns 100 this year! Find out more in a special issue from Science.

Searching for the ultimate test of general relativity, researchers are looking toward the center of our galaxy. There, shrouded in dust, lurks a bright, compact source of radio waves known as Sagittarius A* (Sgr A*). Astronomers think that Sgr A* marks the dark heart of the Milky Way: a supermassive black hole weighing as much as 4 million suns. That black hole produces the most intense gravitational field in our galaxy and so provides a unique laboratory for testing the predictions of general relativity. Over the next few years, using a range of new instruments, astronomers are hoping to see whether Sgr A* is bending relativity beyond breaking point.