For the first time, the “invisible black hole” has been imaged.
Pictures of swirling galaxies, stars, and planets being vacuumed into endless darkness have all been used to describe black holes. However, these artistic interpretations held no confirmed basis other than speculations and theories. Through the work of countless astronomers and computer scientists, the first true picture of these deep mysteries has surfaced.
A global network of eight radio antennae, known as the Event Horizon Telescope, was used to take the image. Spanning across six mountaintops on four continents, the international network is as powerful as a telescope the size of the Earth: powerful enough to snapshot a black hole.
Two black holes were the targets of the EHT. The first, Sagittarius A*, lies in the center of the Milky Way. While Sagittarius A* is the most massive black hole in the galaxy, to take a proper image of it would require immense filtering of light from stars and dust. Thus, scientists decided on another target: M87*. This black hole resides 53 million light-years away in the galaxy Messier 87. M87* is one of the largest known black holes; at 6.5 billion times the mass of the Sun, its size makes up for its distance from Earth, rendering it a worthy choice. What makes M87* interestingly different from Sagittarius A*, apart from its galactic size, is the fact that it is active. M87* is constantly pulling in matter while Sagittarius A* lies dormant, giving scientists another reason to picture it.
For ten days in April of 2017, the EHT was synchronized under relatively favorable weather conditions. All eight antennae were honed in on M87*, detecting signals and waves. After the observation period, the data was physically transported on hard drives to be processed and pieced together. This procedure would last for two years.
Finally, on April 10, 2019, the image of the black hole was revealed. Scientists rejoiced in this groundbreaking revelation, celebrating the beginning of an endless list of possibilities in astronomical discovery. This vital first step into understanding the world of black holes has sparked hope of better understanding these deep space phenomena and their contributions in astrophysics.
– Jessica Jiang