Not a Bird or a Plane – It’s a Comet?!

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Not a Bird or a Plane – It’s a Comet?!

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Last year on December 16, 2017, astronomers got a close-up view of one of the flying objects in space.  The object is an asteroid called Phaethon. It came closer to Earth than it ever had before, about 6 million miles away.  For comparison, Mars is 33 million miles away.  The asteroid Phaethon hasn’t made its closest approach to Earth since 1974.  This gave astronomers around the world a chance to learn more about what the object is and where it came from.  When astronomers first discovered Phaethon in 1983, it had a strange pattern of orbit.  They assumed Phaethon probably was a dead or burnt-out comet because of its orbit, according to Teddy Kareta.  However, “comets are typically red in color, and not blue,” Kareta added. So, it was “hard to say whether Phaethon is more like an asteroid or more like a dead comet.”

Scientists had a theory that Phaethon had broken off from another asteroid, Pallus. However, its brightness suggests it did not. It’s also equally blue around, which means it was somehow evenly “cooked” by the sun’s heat. Phaethon is a strange blue in color.  Teddy Kareta, a researcher/student at the University of Arizona, said that only a small fraction of all known asteroids are blue. Phaethon is also unusual because it has qualities of both a comet and an asteroid. Comets are a different kind of space rock, made up of ice, rock, and space dust.  Asteroids are usually made up of metals and space rock. Astronomers also thought Phaethon was the source of the Geminid meteor shower. Meteors are bits of rock that chip off of flying space rocks when they get near a planet. An example is Earth. The Geminid meteor shower can be seen every year from Earth in early to mid-December.  Before Phaethon’s discovery, comets were thought to be the source of all meteor showers, not asteroids.

NASA, National Aeronautics Space Administration, admits that Phaethon is hard to categorize.  “It is possible that Phaethon is a ‘dead comet’ or a new kind of object being discussed by astronomers as a ‘rock comet.'” Phaethon’s comet-like oval orbit around the sun might be proof of this new idea, NASA reports. “However, scientists are not certain how to define Phaethon,” they said.  When Phaethon passes by the sun, it does not develop a tail like a comet. They noted it looks like a “rocky asteroid.”

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