More Than One Moon For Earth?
December 22, 2011

More Than One Moon For Earth?

Researchers at the University of Hawaii, Honolulu say they have found that Earth could have at least two moons orbiting it at any one time, after finding a near-earth satellite (NES) in our orbit just a few years ago. The scientists then created a model showing how other satellites interact with our gravitational pull.

"At any given time, there should be at least one natural Earth satellite of 1-meter diameter orbiting the Earth,” said Mikael Granvik of UH Honolulu and his colleagues. These objects should hang around for about 10 months and make about three revolutions of the planet. That means Earth ought to have a meter-sized moon right now.

Granvik and his colleagues first discovered a mysterious body orbiting the Earth in 2006. The object turned out to be a small asteroid 5 or 6 feet across, and despite being an asteroid, it was also a natural satellite just like our Moon.

Since that initial discovery, the researchers have been studying how Earth´s gravitational system captures bodies in its orbit while modeling their frequency and duration. The asteroid discovered in 2006 remained in Earth´s orbit for nearly a year before escaping gravitational pull and moving on.

In their paper -- “The Population of Natural Earth Satellites,” published online on the website -- the researchers  wrote that at any given moment, Earth likely has a secret moon orbiting it, although because of their tiny stature, it seems a stretch officially calling them “moons.”

But such a discovery has vast scientific implications.

NASA has talked about sending astronauts to an asteroid in deep space to study and possibly bring back samples. But since our own Earth is continually capturing small asteroids in its orbit, it would potentially be more feasible to send a few astronauts into orbit to study one nearby rather than one hundreds of thousands of miles away.

“The scientific potential of being able to first remotely characterize a meteoroid and then visit and bring it back to Earth would be unprecedented,” the research team concluded.


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