A New Discovery That’s Out of This World

Quasars are considered to be the brightest and most powerful celestial objects in the universe. They emit immense amounts of energy and produce massive amounts of light. They’re about as large as our entire solar system but have the luminosity of a trillion (1,000,000,000,000) stars.

Although quasars were discovered around 60 years ago, the origins of how they formed were unknown. Large galaxies typically have a supermassive black hole at their centers along with plentiful amounts of gas. The gas, however, is usually out of reach from the black hole’s pull; so how could a black hole draw that much fuel and then proceed to produce that much illumination?

Researchers at the Department of Physics and Astronomy at the University of Sheffield, U.K., used observations from the Isaac Newton Telescope—located on the Canary Islands— to finally discover what causes one of the most extraordinary phenomena in our universe. The team compared 48 galaxies that had quasars to 100 galaxies without them. They noticed that the galaxies with quasars were three times more likely to collide with other galaxies than galaxies without quasars. From this, it was deduced that the creation of a quasar is triggered by two galaxies colliding.

Image taken by the Hubble Space Telescope of two spiral galaxies colliding. ESA/Hubble & NASA, W. Keel

A supermassive black hole in a singular galaxy could not produce that much energy due to the gas being unreachable from the black hole. However, when two galaxies collide, large amounts of gas are pushed towards the black hole. Then right before the gas is absorbed by the black hole, enormous amounts of energy is released in the form of jets of radiation. This then creates the amazing celestial spectacle we call quarsars.

Unfortunately, a disadvantage from the formation of quasars is that it pushes the remaining gas out of the galaxy, thus preventing the galaxy from being able to form new stars for billions of years. Nonetheless, a benefit from this study is that we can now predict that a quasar is likely to form when our own Milky Way Galaxy collides with the Andromeda Galaxy in billions of years. It would be a beautiful thing to witness, though humans will most likely be extinct by that time.



My name is Keira Mei, I’m an 11th grader at City this year. I went to John Ball Zoo School in 6th grade and have been going to City ever since. I play the cello and also enjoy playing piano in my free time.

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