First Trojan Asteroid Circling Sun In Earth’s Orbit Discovered

Pasadena – NASA’s Wide-field Infrared Survey Explorer (WISE) mission has discovered the first Trojan asteroid circling the sun in Earth’s orbit. Scientists long believed Earth would have Trojans, but they were difficult to detect.

According to a NASA news release, astronomers  have detected the first Trojan asteroid that is orbiting the sun in our planet’s orbit – Trojans are asteroids that share an orbit with a planet and are locked in by a stable gravitational balance between the sun and a planet.

Scientists have identified Trojans with Jupiter, Mars and Neptune and two of Saturn’s moons.

Before this discovery, it was acknowledged that Earth must have a Trojan asteroid, but there was a great difficulty proving it because they were hard to detect due to their small size and they appear near the sun.

“These asteroids dwell mostly in the daylight, making them very hard to see,” said study head, Martin Connors of Athabasca University. “But we finally found one, because the object has an unusual orbit that takes it farther away from the sun than what is typical for Trojans. WISE was a game-changer, giving us a point of view difficult to have at Earth’s surface.”

The study first began in January 2010 and ended in February of this year. Connors and his team scanned the entire sky using the WISE telescope and then utilized data from NEOWISE, which led to the observation of more than 155,000 asteroids between Mars and Jupiter and 500 near-Earth objects (NEOs).

The search concluded in two Trojan candidates, and ultimately 2010 TK7 was verified as an Earth Trojan, which is 1,000 feet (300 meters) in diameter.

“This observation illustrates why NASA’s NEO Observation program funded the mission enhancement to process data collected by WISE,” said NEOWISE program executive at NASA Headquarters in Washington, Lindley Johnson. “We believed there was great potential to find objects in near-Earth space that had not been seen before."

The discovery is published in the July 28 issue of the journal Nature.