Does Earth Have A Second Moon? Yes, NASA says
The space agency NASA recently announced that Earth has captured an asteroid in its gravitational field, which means that our planet essentially now has a second moon. According to a report from Mother Nature Network, citing a previous report from NASA, scientists have identified a second mini-moon orbiting our planet that researchers believe has only been around for about 100 years. However, this new moon — which has been designated 2016 HO3 — is a lot smaller than our original moon. It was spotted by astronomers at the asteroid survey telescope in Haleakala, Hawaii.
As said in NASA’s report, this new moon will be Earth’s companion at least for a few centuries. In this case, there is no clear definition to what qualifies as a moon or a satellite, but the asteroid 2016 H03 has been termed a moon or “micro-moon” by many popular science sites. The report explains that it is too far away to be considered a true satellite of our planet, but it is the best and most stable example to date of a near-Earth companion, or “quasi-satellite.”
The asteroid, according to NASA, has spent nearly 100 years touring around the Earth and its gravitational relationship with our planet will remain as a satellite for several centuries, revealing the important scientific information about the gravitational relationship with objects nearby Earth.
Scientists say the asteroid is somewhat trapped in a “dance with the Earth” without risk. The asteroid is spinning so that it never wanders more than 100 times the distance of the primary moon and never less than 38 times the distance of the primary moon.
— Discover Magazine (@DiscoverMag) March 12, 2016
As mentioned above, this new moon is relatively small, measuring in at only around 120 feet across and no more than 300 feet wide. Scientists believe it’s small size has been the main reason it has taken so long for it to be spotted. It is undoubtedly large enough to have been discovered long ago but small enough not to be considered as a second moon or even as a satellite.
This small asteroid has — until recently — gone unnoticed, in part, because it has an irregular orbit. Due to its very erratic orbit it has eluded astronomers, according to NASA, although it revolves around the Earth similar to our moon. Some might find it interesting that in an age where companies are investing literally astronomical amounts of money to develop manned missions to Mars or the moon precisely, no one had previously discovered the presence of this small asteroid.
Researchers first noticed 2016 HO3 on April 27 with the Pan-STARRS 1 asteroid survey telescope, which is funded by the Planetary Defense Coordination Office, a company responsible for tracking near-Earth objects. Scientists are confident that the space rock is no threat to our planet or to our primary moon.
“The asteroid’s loops around Earth drift a little ahead or behind from year to year, but when they drift too far forward or backward, Earth’s gravity is just strong enough to reverse the drift and hold onto the asteroid so that it never wanders farther away than about 100 times the distance of the moon,” said Paul Chodas, manager of NASA’s Center for Near-Earth Object (NEO) Studies at the Jet Propulsion Laboratory in Pasadena, California. “The same effect also prevents the asteroid from approaching much closer than about 38 times the distance of the moon. In effect, this small asteroid is caught in a little dance with Earth.”
“Our calculations indicate 2016 HO3 has been a stable quasi-satellite of Earth for almost a century, and it will continue to follow this pattern as Earth’s companion for centuries to come,” Chodas explained.
— Slate (@Slate) June 17, 2016
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