Audience: Middle School Students
There are likely millions of black holes in our galaxy, their location unknown to us. Photo by geralt from Pixabay.
Imagine you are trapped in another universe, stuck forever, with no way out. For eternity, you’ll live there. Maybe it sounds intriguing to you – you’ll get to explore another life, experience a different perspective altogether; perhaps you’ll find your doppelganger! Or maybe the idea of being stuck somewhere foreign frightens you. You’ll never get to live your original life again. You’ll never see your family, your friends, or your favorite shirt again. Everything is gone – irreversible and inescapable. That’s how it would feel if you were light stuck in a black hole.
A black hole is an astronomical object that has a gravitational pull so fierce that nothing can escape it. Take light, for example. It travels at a speed of 299,792,458 meters per second, or about 186,282 miles per second. Once a light particle, called a photon, passes the event horizon (see paragraph 4) of a black hole, it cannot escape. The light rays that pass close to the black hole, but far enough to avoid being caught, are bent by the black hole’s gravity, resulting in the area around a black hole to be a dark disk. M87 is a supermassive black hole located at the galaxy’s heart. Its location? About 55 million light years away. To put that into perspective, one light year is about 6 trillion miles. In context, that means that M87 emitted its light 55 million years ago, and it took that much time to travel from its location to our location.
Black holes are classified into three main types, depending on their mass: Primordial Black Holes, Stellar Black Holes, and Supermassive Black Holes. Primordial Black Holes are believed to have formed in the beginning of the universe, not long after the Big Bang (how the universe began). Their masses range heavily, from the mass of a mountain to that of a star. Stellar Black Holes, on the other hand, form when a massive star’s center collapses, causing a supernova (an exploding star). Its masses generally range from about 3 to 10 times that of the sun. Lastly, Supermassive Black Holes are thought to be formed at the same time their respective galaxy formed. The Supermassive Black Hole’s size correspond with its galaxy’s size and mass.
In addition to the various types of black holes, black holes have very distinct characteristics. The surface of a black hole is called its event horizon. Note that the speed of light is the speed limit of the cosmos, and the event horizon is the boundary where the speed needed to escape the black hole is greater than the speed of light. In other words, at the event horizon, escape becomes impossible. Once light or any other electromagnetic forms pass the event horizon, the gravitational pull becomes so strong that nothing can travel out. It’s a one-way journey. Hypothetically, if a person were to try and enter a black hole, they would undergo a process called spaghettification, which is the stretching and compression, vertically and horizontally, respectively, of an object, caused by powerful gravitational fields.
The first image to serve as proof for the black hole’s existence was taken in 2019 by the Event Horizon Telescope Collaboration, or EHT, with Katie Bouman as a prominent figure in the process to take the image. To do this, scientists combined the power of seven radio telescopes using Very-Long-Baseline-Interferometry, which combines telescopes that are separated by large distances to create continent-sized virtual observatories.
While significant progress has been made in regards to black holes, there is still much to be learned. The event horizon – a daunting existence – provides a fascinating portal into the mysterious realm of black holes. We may never know for sure what is inside a black hole, but its compelling nature will forever captivate scientists and fuel our curiosity about the secrets hidden within its gravitational grasp.
Bibliography:
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Freeman, L. (n.d.). What would happen if you fell into a black hole? BBC Earth. Retrieved January 29, 2024, from https://www.bbcearth.com/news/what-would-happen-if-you-fell-into-a-black-hole
HubbleSite: Black Holes: Gravity's Relentless Pull interactive: Encyclopedia. (n.d.). HubbleSite: Black Holes: Gravity's Relentless Pull interactive: Encyclopedia. Retrieved January 29, 2024, from https://www.stsci.edu/~marel/black_holes/encyc_mod3_q11.html
Strickland, A. (2023, April 14). First photo of a black hole resembles 'skinny' doughnut. CNN. Retrieved January 29, 2024, from https://www.cnn.com/2023/04/14/world/sharp-black-hole-image-scn/index.html
What Are Black Holes? (2020, September 8). NASA. Retrieved January 29, 2024, from https://www.nasa.gov/universe/what-are-black-holes/
What Is a Black Hole? (Grades 5-8). (2022, November 21). NASA. Retrieved January 29, 2024, from https://www.nasa.gov/learning-resources/for-kids-and-students/what-is-a-black-hole-grades-5-8/
What Is a Light-Year? (n.d.). NASA Space Place. Retrieved January 29, 2024, from https://spaceplace.nasa.gov/light-year/en/
What would happen if you fell into a black hole? Spaghettification explained. (n.d.). Royal Museums Greenwich. Retrieved January 29, 2024, from https://www.rmg.co.uk/stories/topics/what-happens-if-you-fall-black-hole
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