UNLV professor: Asteroid has likely been visiting Earth orbit for billions of years

Although it’s hard to spot without a decent telescope, the mini moon is here through Nov. 25.

The only similarity between the mini moon and Earth’s moon is they are both made of rocks, said Jason Steffen, an astrophysicist at UNLV.

The mini moon is 10 meters wide, or as big as a goal post at a football game, whereas Earth’s moon is the size of the United States.

The mini moon is a part of the asteroid belt called the Arjuna asteroids, Steffen said. It has a similar orbit to Earth’s and is close to the plane where all the planets orbit.

“We’ve only been able to see them for 20 years, so it happens quite a bit,” Steffen said. “Which means that it must have been happening for the last 4 1/2 billion years.”

Really small objects in the solar system can tell people information about the history of the solar system, Steffen said. As the planets form and move around, the small objects get scattered and can smash into planets.

“The objects that can survive for long periods of time get whittled down,” Steffen said. “You can basically trace the history of the solar system by looking at what kinds of things are able to survive.”

One example of this is Pluto, Steffen said. Pluto orbits Neptune twice for every three trips Neptune orbits the sun.

Neptune was formed closer to the sun than it’s currently located. As Neptune traveled farther from the sun, it captured a bunch of small objects like Pluto’s orbit.

By studying the Arjuna asteroids, scientists can determine how many of these objects were near Earth’s distance when the Earth was forming and how the solar system around Earth has changed, Steffen said.

“It’s interesting whenever (an asteroid) comes around, but it’s not so frequent that it’s boring,” Steffen said. “Lunar eclipses come around roughly the same amount of time … but people still want to hear about it.”

 

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