Trojan Asteroid Shares Earth's Orbit Around the Sun [PHOTOS & VIDEO]

Astronomers discovered the Earth has a Trojan asteroid friend with which it does the sun dance.

Trojans are asteroids that share an orbit with a planet, and circle around the sun in front of or behind the planet. They ride in the same orbit as a planet and never cross its path or collide with it.

Asteroid 2010 TK7 was discovered by NEOWISE, the asteroid-hunting section of NASA's WISE mission. It was confirmed as the first Earth Trojan after follow up observations with the Canada-France-Hawaii Telescope on Mauna Kea in Hawaii, NASA said.

Scientists have for some time thought Earth should have Trojans. However, those kinds of asteroids were hard to find because they are relatively small and appear near the sun from Earth's point of view, according to NASA.

The new discovery can be read in the July 28 issue of the journal Nature.

"These asteroids dwell mostly in the daylight, making them very hard to see," said Martin Connors from Athabasca University in Canada, in a statement from NASA. "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."

Connors is the lead author of a new paper on the discovery.

Asteroid 2010 TK7 is about 1,000 feet (300 meters) in diameter, has an unusual orbit, and is about 50 million miles (80 million kilometers) from Earth. It has an extreme orbit that takes it far above and below the plane of Earth's orbit. It has a well-defined orbit and for the next 100 years, won't come closer to Earth than 15 million miles (24 million kilometers).

Trojan asteroids also share orbits with other planets in our Solar System to include Neptune, Mars and Jupiter.

WISE was able to spot 2010 TK7 because of its unusual orbit that takes it as far as 90 degrees away from the sun, according to NASA.

According to the space agency, the WISE telescope scanned the entire sky in infrared light from last January to February this year. The NEOWISE project has 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, NASA said.

"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 always is chasing this asteroid around."

But don't expect NASA to plan a visit to asteroid 2010 TK7 any time soon.

Earth's first Trojan wouldn't be a good target for robotic or human exploration because it travels too far above and below the plane of Earth's orbit, and would require large amounts of fuel to reach it.

Asteroid 2010 TK7 was discovered by NEOWISE, the asteroid-hunting section of NASA's WISE mission. It was confirmed as the first Earth Trojan after follow up observations with the Canada-France-Hawaii Telescope on Mauna Kea in Hawaii.

This latest image from NASA's Wide-field Infrared Survey Explorer, or WISE, shows three different nebulae located in the constellation of Perseus. NGC 1491 is seen on the right side of the image, SH 2-209 is on the left side and BFS 34 lies in between. The picture covers an area on the sky equal to 8 full moons. It is easy to think that celestial objects like the three in this image are located at the same distance from Earth, as if they were placed on the dome of a planetarium. In reality, objects that appear close together on the sky can actually be quite far apart. In this case, NGC 1491 and BFS 34 are part of the same cloud complex located at a distance of about 10,700 light-years away in the Perseus arm of the Milky Way Galaxy. SH 2-209 is farther away at about 16,000 light-years distance, located in the outer arm of the Milky Way. NGC 1491 can be seen in visible light with an optical telescope. In contrast, SH 2-209 disappears completely in visible light, obscured by dust.

Although they are not structurally associated with each other, the nebulae do have much in common. All three are members of the same "family" of objects called HII regions by astronomers. HII regions are created when ultraviolet radiation from hot stars ionizes the surrounding gas, causing it to glow in visible light. The surrounding dust is also heated by this radiation and we see it glow in infrared light. These regions are well known for being places where new stars are born. In this image, the star cluster [BDS2003] 65 is developing within the SH 2-206 nebula. The bright spot in the center of BFS 34 nebula is the growing star cluster [BDS2003] 63.

Color in this image represents specific wavelengths of infrared light. Blue and cyan (blue-green) represent wavelengths of 3.4 and 4.6 microns, respectively. In this image, most of the light emitted at these wavelengths is from hot stars. Green and red represent 12- and 22-micron light, which is mainly from warm dust.

A rich collection of colorful astronomical objects is revealed in this picturesque image of the Rho Ophiuchi cloud complex from NASA's Wide-field Infrared Explorer, or WISE. The Rho Ophiuchi cloud (pronounced 'oh-fee-yoo-ki' and named after a bright star in the region) is found rising above the plane of the Milky Way in the night sky, bordering the constellations Ophiuchus and Scorpius. It's one of the nearest star-forming regions to Earth, allowing us to resolve much more detail than in more distant similar regions, like the Orion nebula.

The amazing variety of colors seen in this image represents different wavelengths of infrared light. The bright white nebula in the center of the image is glowing due to heating from nearby stars, resulting in what is called an emission nebula. The same is true for most of the multi-hued gas prevalent throughout the entire image, including the bluish, bow-shaped feature near the bottom right. The bright red area in the bottom right is light from the star in the center - Sigma Scorpii - that is reflected off of the dust surrounding it, creating what is called a reflection nebula. And the much darker areas scattered throughout the image are pockets of cool, dense gas that block out the background light, resulting in absorption (or 'dark') nebulae. WISE's longer wavelength detectors can typically see through dark nebulae, but these are exceptionally opaque.

The bright pink objects just left of center are young stellar objects (YSOs). These baby stars are just now forming; many of them are still enveloped in their own tiny compact nebulae. In visible light, these YSOs are completely hidden in the dark nebula that surrounds them, which is sometimes referred to as their baby blanket. We can also see some of the oldest stars in our Milky Way galaxy in this image, found in two separate (and much more distant) globular clusters. The first cluster, M80, is on the far right edge of the image towards the top. The second, NGC 6144, is found close to the bottom edge near the center. They both appear as small densely compacted groups of blue stars. Globular clusters such as these typically harbor some of the oldest stars known, some as old as 13 billion years, born soon after the universe formed.

There are two other items of interest in this image as well. At the 3 o'clock position, relative to the bright central region, and about two-thirds of the way from the center to the edge, there is a small faint red dot (more visible in the larger downloadable image files). That dot is an entire galaxy far far away known as PGC 090239. And, at the bottom left of the image, there are two lines emerging from the edge. These were not created by foreground satellites; they are diffraction spikes (optical artifacts from the space telescope) from the bright star Antares that is just out of the field of view.

The colors used in this image represent specific wavelengths of infrared light. Blue and cyan (blue-green) represent light emitted at wavelengths of 3.4 and 4.6 microns, which is predominantly from stars. Green and red represent light from 12 and 22 microns, respectively, which is mostly emitted by dust.

In the Perseus spiral arm of the Milky Way galaxy, opposite the galactic center, lies the nebula SH 2-235. As seen in visible light, SH 2-235 appears to be a small amber-colored dust cloud that spans about a tenth the size of the full moon. In infrared light, NASA's Wide-field Infrared Survey Explorer, or WISE, reveals SH 2-235 to be a huge star formation complex - more than 100 light-years across -- as seen in this new view. This image covers an area of the sky nearly five times as high and wide as the full moon (2.44 by 2.44 degrees). which is mostly light from warm dust.

SH 2-235 is so named because it is a nebula found in the Sharpless Catalogue. In 1959, Stewart Sharpless from the United States Naval Observatory published a comprehensive catalogue of ionized, or charged, gas clouds, called HII regions, north of minus 27 degrees declination (declination specifies an object's location on the sky in the same way that latitude does on Earth). The Sharpless Catalogue includes many objects that are commonly known by other names, such as the great Orion nebula, or SH 2-281. However, in the case of SH 2-235, no other name exists to describe this particular region. which is mostly light from warm dust.

SH 2-235 was created when two giant clouds collided. The dense material is heated by the star BD+35°1201, causing the cloud's dust to glow. SH 2-235 is part of a larger cloud complex that includes three other Sharpless HII regions (SH 231, 232, 233). This complex is interesting because it includes examples of several evolutionary stages of star development. For example, the bright orange objects on the lower right (south eastern) part of the nebula are a cluster of stars that are forming into massive stars out of cold clumps. This area is important for studying the early stages of massive star formation, which is still not well understood. which is mostly light from warm dust.

Another mysterious object seen in this image is IRAS 05338+3447, the bright red object in the lower right corner. This object was seen by the Infrared Astronomical Satellite, or IRAS, as an indistinct bright spot. The WISE image shows the object much more clearly, but does not immediately reveal if it is associated with the larger star-forming region. There are also several red-colored stars in this image, which are likely young stellar objects. These are baby stars wrapped up in blankets of dust that glow brightly in infrared light which is mostly light from warm dust.

Color in this image represents specific wavelengths of infrared light. Blue and cyan (blue-green) represent 3.4- and 4.6-micron wavelengths, which is primarily light emitted from hot stars. Green and red represent 12- and 22-micron wavelengths, which is mostly light from warm dust.

In Greek mythology, Orion was a hunter whose vanity was so great that he angered the goddess Artemis. As his punishment, Artemis banished the hunter to the sky where he can be seen as the famous constellation Orion. In the constellation, Orion's head is represented by the star Lamdba Orionis (fuzzy red dot in middle). When viewed in infrared light, NASA's Wide-field Infrared Survey Explorer, or WISE, shows a giant nebula around Lambda Orionis, inflating Orion's head to huge proportions.

Lambda Orionis is a hot, massive star that is surrounded by several other hot, massive stars, all of which are creating radiation that excites a ring of dust, creating the "Lambda Orionis molecular ring." Also known as SH 2-264, the Lambda Orionis molecular ring is sometimes called the Meissa ring. In Arabic, the star Lambda Orionis is known as "Meissa" or "Al-Maisan," meaning "the shining one." The Meissa Ring is of interest to astronomers because it contains clusters of young stars and proto-stars, or forming stars, embedded within the clouds. With a diameter of approximately 130 light-years, the Lambda Orionis molecular ring is notable for being one of the largest star-forming regions WISE has seen. This is also the largest single image featured by WISE so far, with an area of the sky approximately 10 by 10 degrees in size, equivalent to a grid of 20 by 20 full moons. Nevertheless, at less than one percent of the whole sky's area, it is just a taste of WISE data.

The bright blue star in the lower left corner of the image is the star Betelgeuse, which represents one shoulder of the hunter Orion. The name Betelgeuse is actually a corruption of the original Arabic phrase "Yad al-Jauza'," meaning "hand of the giant one." Betelgeuse is well known for being a red supergiant star, yet in WISE's infrared view it appears blue, as do most stars in WISE images. This is because most stars, including Betelgeuse, put out more light in the shortest infrared wavelengths of light captured by WISE, and those shorter wavelengths are presented in WISE images as blue and cyan.

In visible light, Orion's other shoulder is clearly marked by the variable star Bellatrix. In infrared light, however, Bellatrix is a somewhat unremarkable cyan-colored star in the right side of the image. In Latin, Bellatrix means "female warrior," which is perhaps why the name was chosen for a female witch character in the popular Harry Potter books.

Also seen in this image are two dark nebulae, Barnard 30 and Barnard 35, which are parts of the Meissa ring that are so dense they block out visible light. Barnard 30 is the bright knob of gas and dust in the top center part of the image. Barnard 35 appears as a hook extending towards the center of the ring just above and to the right of the star Betelgeuse. The bright reddish object seen to in the middle right part of the image is the star HR 1763, which is surrounded by another star-forming region, LBN 867.

Color in this image represents specific wavelengths of infrared light. Blue and cyan represent 3.4- and 4.6-microns, primarily light emitted by hot stars. Green and red represent 12- and 22-micron light, which is mainly radiation from warm dust.

NASA’s Wide-field Infrared Survey Explorer, or WISE, is a little like the Vincent van Gogh of the infrared sky. Just like the famous Impressionist painter created beautiful images of nature through use of color and light, WISE has provided the world with picturesque images of the cosmos by representing infrared light through color. This image of the nebula NGC 2174, on the border of the Gemini and Orion constellations, is a perfect example. The colors in this image may look like brush strokes of paint but actually represent specific wavelengths of infrared light. Particles of interstellar dust are warmed by the star cluster in the center of the nebula, and glow in wavelengths of 12 and 22-microns, which WISE represents by the colors green and red. The blue and cyan (blue-green) stars scattered throughout the “canvas” of the image are hot compared to the dust, and emit light at 3.4 and 4.6 microns.

Affectionately called the “Monkey nebula” by some, NGC2174 is a cloud of gas and dust that surrounds the star cluster NGC2175. As the star cluster heats up the nebula, the dust begins to glow in infrared light. Strong winds and radiation from the stars blow away the nearby material, creating a shell-like structure. NGC2174 was discovered in 1877 by French astronomer Jean Marie Stephan, who used an 80-centimeter reflecting telescope at the Observatoire de Marseille, France. Today, it is a favorite target for amateur astronomers because it can be seen in binoculars or a small telescope.

Another nebula can be seen in the upper half of this image. In this case, the gas is hollowed out by a massive star named TYC 1326-964-1. The matter in between the stars in this nebula is named [GS55] 85, after the initials of the astronomers who first catalogued it in the 1950s. Several red-colored young stellar objects can be seen scattered throughout this nebula. These are newly formed stars still enshrouded in a cloud of dust. Near the top and toward the left of the image lies a bright blue star known as HR2190, which is actually a red dwarf star. Red dwarfs are on the cooler and dimmer side for stars, so the relative brightness of HR2190 in the image means that it is much closer to us than the nebula.

Star clusters such as the Pleiades are often considered some of the most beautiful objects in the sky. Yet in this image taken by NASA’s Wide-field Infrared Survey Explorer, or WISE, the star cluster NGC 2259 is overshadowed by the surrounding stars and dust which glow brightly in infrared light.

In the same way that dust is blown around by the wind here on Earth, space dust can be blown around by the wind and radiation from stars. This image of the Elephant's Trunk nebula from NASA's Wide-field Survey Explorer, or WISE, shows clouds of dust and gas being pushed and eroded by a massive star. The bright 'trunk' of the nebula near the center is an especially dense cloud holding up against the star's powerful radiation and stellar wind, like a windsock standing strong while the rest of the gas and dust gets broken up and swept away.

'Elephant trunk' is a term commonly used by astronomers for this type of structure. Similar structures can be found in many other nebulae, however this is the only nebula that uses the term in its moniker. More distant examples of elephant trunks can be seen in previously featured WISE images such as LBN 211.91-01.37 and the Soul nebula. They're all formed in basically the same way -- a nearby massive star (or cluster) emits vast amounts of ultraviolet radiation and stellar winds that clear out all of the gas and dust surrounding it, leaving behind only the most dense parts of the cloud. These dense portions then protect some of the gas 'downwind' creating a trunk-like feature.

The culprit star here, HR8281, is located close the center of the image. It's one of the three bright blue stars near the upper left tip of the trunk that form a triangle about as wide as the glowing tip of the trunk. Of those three, it's the uppermost one in the center. Its destructive effects on the surrounding nebula can be seen by the dark cavity it's created, outlined by the brighter dust clouds encircling it. The entire nebula, also known as IC1396A, fills most of the field of view. It's located only 2,450 light-years away, quite close compared to other similar nebulae. The trunk itself is about 30 light-years long, while the full nebula stretches over 100 light-years across.

If you look closely at the tip of the elephant trunk you can see a small dark area, appearing as a sort of opening. This is a small void in the gas formed by a pair of new baby stars that recently formed in the dense cloud. Their radiation and wind is clearing out the nearby gas and dust, creating a smaller version of the same effect seen on a larger scale in the full image. The reddish stars scattered throughout the image are likely new stars still wrapped inside their dusty cocoons.

The colors used in this image represent specific wavelengths of infrared light. Blue and cyan (blue-green) represent light emitted at wavelengths of 3.4 and 4.6 microns, which is predominantly from stars. Green and red represent light from 12 and 22 microns, respectively, which is mostly emitted by dust.

This image from NASA's Wide-field Infrared Survey Explorer, or WISE, highlights several star-forming regions.

This image is a map of the portion of the sky covered by the preliminary release of WISE data. WISE surveyed the entire sky in four infrared wavelengths in 2010. On April 14, 2011, the WISE team released data representing 57 percent of the sky as seen by WISE. This preliminary release will allow astronomers and astronomy enthusiasts worldwide to explore the sky as seen by WISE.

The sky can be thought of as a sphere that surrounds us in three dimensions. To make a map of the sky, astronomers project it into two dimensions. Various methods are used to project 3-D objects into 2-D maps, but the projection used in this image of the sky is called Aitoff, named after the geographer who invented it. It takes the 3-D sky sphere and slices open one hemisphere, and then flattens the whole thing out into an oval shape. Any projection creates distortions, so people often pick the projection type based on which distortions they want to minimize. This map is centered on the Milky Way galaxy. The plane of the galaxy runs along the equator, and the middle of the galaxy is at the center of the map, where projection distortions are minimal.

The gray regions are the part of the sky not available in the preliminary WISE data release. For the regions with data, the colors used are representational: blue and cyan (blue-green) represent data from the 3.4- and 4.6-micron detectors aboard WISE, and green and red represent data from the 12- and 22-micron detectors. The blue and cyan reveals mostly light from stars, while the green and red come from mostly warm dust.