The first Trojan asteroid found to share Earth’s orbit was discovered by NASA scientists.
The asteroid is approximately the length of several football fields and 50 million miles from the Earth. It is not expected to get closer than 15 million miles to the planet.
Trojan asteroids are so named because they lead or follow similar orbits of other planets. Other planets such as Neptune and Jupiter have Trojan asteroids.
“It’s as though Earth is playing follow the leader,” said Amy Mainzer, the principal investigator of NEOWISE at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “Earth is always chasing this asteroid around.”
This is how Mainzer describes the unusual patterns that the asteroid and Earth travel in relation to each other and the Sun.
Trojan asteroids follow certain points in space that are considered stable in relation to two larger bodies, such as the Sun and the Earth.
The centripetal force that results from the pull of gravity between the Sun and the Earth allows this asteroid to spin alongside them.
Earth’s Trojan asteroid is especially unique in that it travels both above and below the plane of the Earth in its orbit; making it not so cost-effective for future space expeditions.
But another reason for its distinctiveness is primarily why it was hard to find in the first place.
“The object has an unusual orbit that takes it farther away from the sun than what is typical for Trojans,” explains Martin Connors of Athabasca University in Canada, lead author of the paper describing this find in the July 28 issue of the journal Nature.
NASA’s Wide-field Infrared Space Explorer (WISE) telescope surveyed the night skies above Grand Rapids and the rest of world from January 2010 and February 2011. It chose the 2010 TK7 asteroid after confirming data from the Canada-France-Hawaii Telescope on Mauna Kea in Hawaii.
To view a NASA animation on the unusual Trojan asteroid’s orbit go here.
Explore the beautiful night skies at your local Grand Rapids planetarium, the Roger B. Chaffee planetarium.
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