The Milky Way Black Hole & What We Know About It

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The Milky Way Black Hole & What We Know About It

Event Horizon Telescope (EHT) Collaboration

Authored by: Dominique Jenkins | Communications Intern

One of the biggest mysteries of our universe is the existence of black holes. Black holes are areas in the universe that have immensely strong gravitational pulls. In fact, the gravity of black holes is so strong that nothing can escape them—not even light. This theoretical “point of no return” is known as the event horizon. Black holes are impossible to see with the naked eye and nearly impossible to detect without special telescopes and equipment.

Most galaxies have black holes at their centers, and recently, astronomers were able to capture the first images of Sagittarius A* (pronounced Sagittarius A-star), the black hole at the center of the Milky Way. While this isn’t the first black hole to be photographed, the images of Sagittarius A* will provide scientists with tons of new information about our galaxy and universe.

What is Sagittarius A*?

Sgr A* is the name of the black hole at the center of the Milky Way galaxy. Its name comes from its position near the border between the constellations Sagittarius and Scorpius. Sgr A* was originally discovered by astronomers Robert Brown and Bruce Balick in the 1970s. It is believed to have formed from the explosion of a star.

How Big is Sgr A*?

Sgr A* is relatively small compared to other known black holes. It is estimated to have a mass more than four million times that of the Sun. The mass of Sgr A* classifies it as a supermassive black hole. A black hole is considered supermassive if it has a mass greater than one million times that of the Sun. Astronomers have also measured the diameter of Sgr A* and determined that it is about 27 million miles wide, which is similar to the distance between the Sun and Mercury.

Where is Sgr A*?

Sgr A* is located at the center of the Milky Way. The distance from the black hole to Earth is estimated to be between 26 – 27,000 light-years or around 160 quadrillion miles away.

The Significance of Locating Sgr A*

With these new images of Sgr A*, scientists will be able to further investigate the Theory of General Relativity coined by Albert Einstein in 1915. Through observations and experimentation, scientists can gain a better understanding of how black holes are impacted by gravity. Additionally, with advances in technology, scientists hope to learn more about event horizons and how black holes interact with the rest of the universe.