Event Horizon Telescope's Black Hole Image

On April 10, 2019, the Event Horizon Telescope team took the first ever image of a black hole. This image, which was of Messier 87, an elliptical galaxy 55 million light years away from Earth, represented an international collaborative effort between eight different telescopes around the world (Landau, 2019). I still remember where I was when I first saw the image in 2019. I was a senior in high school in my science class. I saw the image pop up on my phone, and I immediately remember being amazed by the picture and showing all my friends. We finally had visual evidence of the existence of black holes. I was excited to be going into this field of study after I graduated. 

Black holes, ever since they were theorized in 1916 by Albert Einstein, have been a source of great mystery to everyone (Taylor Redd, 2019). In theory, they existed, but nobody had ever captured an image to serve as visual evidence. A black hole was first spotted in 1964 when scientists saw gas being sucked away from a nearby star (Choi, 2021). The gas spiraled into something, where it became so hot that it started emitting x-rays and gamma rays (Choi, 2021). Scientists could then detect these high-energy forms of light via satellites. Scientists determined that the “something” must be a black hole, and they named it Cygnus X-1 (Choi, 2021). Since then, scientists have discovered several other black holes, but no one could figure out how to take an image of one. Since black holes have such an extreme gravitational pull, nothing, not even light, can escape its pull, it would be notoriously hard to take a picture of it. However, a team of scientists eventually figured how to do it just a few years ago. 

With the help of eight different observatories around the world (and cooperating weather), scientists were able to take the first-ever image of a black hole. The team knew they must have the largest aperture possible to take a picture of something so far away. Larger aperture (or diameter) on a telescope means larger collecting area, thus more photons collected. So they collaborated with eight different observatories around the world, from Antarctica to Spain,  and aimed them all at the same location in the sky at the same time, with all of them attuned to the same frequency of light (X-rays). By doing this, the team essentially created one big telescope that had an aperture of nearly the diameter of Earth (Event Horizon Telescope, 2021). They promptly named it the Event Horizon Telescope (Landau, 2019) and aimed it at Messier 87 to find the black hole. 

Then, in 2019, the Event Horizon Telescope Team finally released the first-ever image of a black hole. You can see the glowing swirl of orange gas around the black hole, just outside the event horizon (Landau, 2019). However, the team didn’t stop there. Just a few days ago, the Event Horizon Telescope Team just released another photo of the same black hole, but with more detail than before. They used polarized light to gather more information about the black hole and how it can influence magnetic fields (Event Horizon Telescope, 2021). The Event Horizons Telescope Team is currently analyzing the data from this new image and making new discoveries, such as how the magnetic fields around the black hole can allow the object to shoot powerful jets and consume matter (Event Horizon Telescope, 2021). This project is still ongoing and making new discoveries every day.

Chandra X-ray Observatory’s close up of the galaxy with the black hole in its center (Landau, 2019)

Image of M87 (Landau, 2019)

Image of M87 viewed through polarized light (Event Horizon Telescope, 2021)

References:

Choi, C. Q. (2021, February 19). Scientists revisit the 1st black hole they ever discovered and realize it's bigger than they thought. Space.com. https://www.space.com/first-discovered-black-hole-larger-than-thought

Event Horizon Telescope. (2021, March 24). Astronomers Image Magnetic Fields at the Edge of M87’s Black Hole. Event Horizon Telescope. https://eventhorizontelescope.org/blog/astronomers-image-magnetic-fields-edge-m87s-black-hole

Landau, E. (2019, April 10). Black Hole Image Makes History; NASA Telescopes Coordinated Observations. NASA. https://www.nasa.gov/mission_pages/chandra/news/black-hole-image-makes-history

Taylor Redd, N. (2019, July 11). What Are Black Holes? Space.com. https://www.space.com/15421-black-holes-facts-formation-discovery-sdcmp.html