Black holes are super dense objects that hypothetically exist in our universe. They have a gravitational pull so strong that any object that gets close enough falls in and can’t escape, including light. These objects often have a mass tens to millions of times greater than the mass of our sun. While we have predicted their existence for a hundred years, only recently have scientists been able to take the first ever photograph of a black hole.
The Event Horizon Telescope (EHT) collaboration has been working to image black holes at the center of galaxies. The collaboration, made from institutions around the world, released the first image of a black hole at the center of the distant galaxy Messier 87 (M87). Black holes do not reflect or emit light (thus ‘black’ hole). It would be impossible to see a black hole in empty space. However, central black holes like the one in M87 have lots of space gas (random clouds of atoms and molecules) circling around it. These particles can interact with and emit light. Some of that light gets eaten by the black hole, but some also propagates far enough to reach Earth. The EHT observes this light with telescopes around the world. The combined data of all the telescopes increases the resolution of the image, allowing scientists to photograph something as difficult as photographing individual grains of sand on a beach from an airplane.
This photograph is important for the study of black holes and Einstein’s general relativity. The picture matched simulations scientists had run, confirming our understanding of this mysterious object. The EHT is in the process of imaging another black hole nearer to our galaxy, which may further confirm our theoretical predictions regarding black hole size, electric charge, and mass or reveal new information regarding black holes.
Managing Correspondent: Cari Cesarotti
Image Credit: The Event Horizon Telescope Collaboration, via National Science Foundation