Thursday, July 28, 2011

NASA's WISE Mission Finds First Trojan Asteroid Sharing Earth's Orbit


More eyes in sky to see what we have not seen before.
There has often be a question if anything was out there some 60 degree ahead or behind Earth in its orbit around the Sun.
Jupiter, Saturn, yes, Earth, hmmmm.
- LRK -

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In astronomy, the word trojan refers to a minor planet or natural satellite (moon) that shares an orbit with a larger planet or moon, but does not collide with it because it orbits around one of the two Lagrangian points of stability (Trojan points), L4 andL5, which lie approximately 60° ahead of and behind the larger body. Trojan objects are one type of co-orbital object.
Trojan asteroids are Small Solar System Bodies that reside in Trojan points. Trojan moons are moons that reside at Trojan points. Trojan planets are theoretical planets that reside at Trojan points.
Saturn has the most known Trojan satellites: Saturn's moon Tethys has two Trojan moons (Telesto and Calypso), and Dionealso has two Trojan moons (Helene and Polydeuces).

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Well now we know, something out there.
- LRK -

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NASA's WISE Mission Finds First Trojan Asteroid Sharing Earth's Orbit

This artist's concept illustrates the first known Earth Trojan asteroid, discovered by WISE.
This artist's concept illustrates the first known Earth Trojan asteroid, discovered by WISE
Full image link.

PASADENA, Calif. – Astronomers studying observations taken by NASA's Wide-field Infrared Survey Explorer (WISE) mission have discovered the first known "Trojan" asteroid orbiting the sun along with Earth.
Trojans are asteroids that share an orbit with a planet near stable points in front of or behind the planet. Because they constantly lead or follow in the same orbit as the planet, they never can collide with it. In our solar system, Trojans also share orbits with Neptune, Mars and Jupiter. Two of Saturn's moons share orbits with Trojans.
Scientists had predicted Earth should have Trojans, but they have been difficult to find because they are relatively small and appear near the sun from Earth's point of view.
"These asteroids dwell mostly in the daylight, making them very hard to see," said Martin Connors of Athabasca University in Canada, lead author of a new paper on the discovery in the July 28 issue of the journal Nature. "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 WISE telescope scanned the entire sky in infrared light from January 2010 to February 2011. Connors and his team began their search for an Earth Trojan using data from NEOWISE, an addition to the WISE mission that focused in part on near-Earth objects, or NEOs, such as asteroids and comets. NEOs are bodies that pass within 28 million miles (45 million kilometers) of Earth's path around the sun. The NEOWISE project observed more than 155,000 asteroids in the main belt between Mars and Jupiter, and more than 500 NEOs, discovering 132 that were previously unknown.

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Repeat with maybe larger print.
- LRK -

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NASA's Wise Mission Finds First Trojan Asteroid Sharing Earth's Orbit
  • Source: NASA HQ
  • Posted Wednesday, July 27, 2011
WASHINGTON -- Astronomers studying observations taken by NASA's Wide-field Infrared Survey Explorer (WISE) mission have discovered the first known "Trojan" asteroid orbiting the sun along with Earth.

Trojans are asteroids that share an orbit with a planet near stable points in front of or behind the planet. Because they constantly lead or follow in the same orbit as the planet, they never can collide with it. In our solar system, Trojans also share orbits with Neptune, Mars and Jupiter. Two of Saturn's moons share orbits with Trojans.

Scientists had predicted Earth should have Trojans, but they have been difficult to find because they are relatively small and appear near the sun from Earth's point of view.

"These asteroids dwell mostly in the daylight, making them very hard to see," said Martin Connors of Athabasca University in Canada, lead author of a new paper on the discovery in the July 28 issue of the journal Nature. "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."

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Check out NASA home page.
- LRK -

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Many choices at NASA home page.
- LRK -

Trojan Asteroid Shares Orbit With Earth

Astronomers studying observations taken by the Wide-field Infrared Survey Explorer mission have discovered the first known "Trojan" asteroid orbiting the sun along with Earth.
› Learn More  
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The WISE mission has many more images.
- LRK -

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WISE First Images

Wide-field Infrared Survey Explorer

Mission Overview

Thanks to next-generation technology, WISE's sensitivity is hundreds of times greater than its predecessor, the Infrared Astronomical Satellite, which operated in 1983.The Wide-field Infrared Survey Explorer, or WISE, will scan the entire sky in infrared light, picking up the glow of hundreds of millions of objects and producing millions of images. The mission will uncover objects never seen before, including the coolest stars, the universe's most luminous galaxies and some of the darkest near-Earth asteroids and comets. Its vast catalogs will help answer fundamental questions about the origins of planets, stars and galaxies, and provide a feast of data for astronomers to munch on for decades to come.  
WISE will join two other infrared missions in space -- NASA's Spitzer Space Telescope and the Herschel Space Observatory, a European Space Agency mission with important NASA participation. WISE is different from these missions in that it will survey the entire sky. It is designed to cast a wide net to catch all sorts of unseen cosmic treasures, including rare oddities.

The closest of WISE's finds will be near-Earth objects, both asteroids and comets, with orbits that come close to crossing Earth's path. The mission is expected to find hundreds of these bodies, and hundreds of thousands of additional asteroids in our solar system's main asteroid belt. By measuring the objects' infrared light, astronomers will get the first good estimate of the size distribution of the asteroid population. This information will tell us approximately how often Earth can expect an encounter with a potentially hazardous asteroid. WISE data will also reveal new information about the composition of near-Earth objects and asteroids -- are they fluffy like snow or hard like rocks, or both?

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Well I hope we continue to be able to look up.
Too much talking about U.S. debt limits and the budget, but that is another story.
- LRK -

Thanks for looking up with me.
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WHAT THE MIND CAN CONCEIVE, AND BELIEVE, IT WILL ACHIEVE - LRK -

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