After traveling two billion miles over more than two years, NASA's OSIRIS-REx spacecraft has arrived at asteroid Bennu. The spacecraft will survey the asteroid, collect a sample, and bring it back home in 2023. From NASA's Goddard Space Flight Center/University of Arizona:
This series of images taken by the OSIRIS-REx spacecraft shows Bennu in one full rotation from a distance of around 50 miles (80 km). The spacecraft’s PolyCam camera obtained the thirty-six 2.2-millisecond frames over a period of four hours and 18 minutes.
Below is a set of images compiled during OSIRIS-REx's approach. Learn more at: ISIRIS-REx: Asteroid Sample Return Mission.
From NASA/Goddard/University of Arizona:
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From Aug. 17 through Nov. 27 the spacecraft’s PolyCam camera imaged Bennu almost daily as the spacecraft traveled 1.4 million miles (2.2 million km) toward the asteroid. The final images were obtained from a distance of around 40 miles (65 km). During this period, OSIRIS-REx completed four maneuvers slowing the spacecraft’s velocity from approximately 1,100 mph (491 m/sec) to 0.10 mph (0.04 m/sec) relative to Bennu, which resulted in the slower approach speed at the end of the video.
Over the weekend, Arizona's Catalina Sky Survey spotted a near-earth asteroid just a few hours before its impact trajectory took it right into our atmosphere. Luckily, it burned up before impact. Read the rest
The asteroid belt holds untold wealth for the prospectors who can reach and mine them. Wired UK just published an interesting chart of select asteroids valued between 1 and 27 quintillion dollars each. Read the rest
“We already knew of many asteroids, but they have all been baked by billions of years near the Sun,” says Karen Meech of the University of Hawaii’s Institute for Astronomy. “This one is the first uncooked asteroid we could observe: it has been preserved in the best freezer there is.”
C/2014 S3 (aka PANSTARRS) was formed about 4.5 billion years ago, close to Earth when it was formed. But PANSTARRS traveled far from the sun, "preserved in the deep freeze of the Oort Cloud for billions of years." Now it is headed back, and astronomers are excited to see what fresh frozen ancient asteroid looks like.
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Careful study of the light reflected by C/2014 S3 (PANSTARRS) indicates that it is typical of asteroids known as S-type, which are usually found in the inner asteroid main belt. It does not look like a typical comet, which are believed to form in the outer Solar System and are icy, rather than rocky. It appears that the material has undergone very little processing, indicating that it has been deep frozen for a very long time. The very weak comet-like activity associated with C/2014 S3 (PANSTARRS), which is consistent with the sublimation of water ice, is about a million times lower than active long-period comets at a similar distance from the Sun.
The authors conclude that this object is probably made of fresh inner Solar System material that has been stored in the Oort Cloud and is now making its way back into the inner Solar System.
NASA movie of asteroid 2012 DA14 flying away from Earth last week. I had no idea it was built in Minecraft!
"Since regular sky surveys began in the 1990s," says Don Yeomans of NASA's Near Earth Object Program says, "we've never seen an object this big get so close to Earth." That's about 5% of the average distance between the Earth and the Moon. (See also: The Last Policeman: solving a murder before an asteroid wipes out life on Earth.) Read the rest
The green circle in the lower right of this image marks the position of Earth's own trojan asteroid, discovered by researcher's involved with NASA's Wide-field Infrared Survey Explorer project.
What's a trojan asteroid? Glad you asked. The good news: It's not going to kill us all.
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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.
The team's hunt resulted in two Trojan candidates. One called 2010 TK7 was confirmed as an Earth Trojan after follow-up observations with the Canada-France-Hawaii Telescope on Mauna Kea in Hawaii.
The asteroid is roughly 1,000 feet (300 meters) in diameter. It has an unusual orbit that traces a complex motion near a stable point in the plane of Earth's orbit, although the asteroid also moves above and below the plane. The object is about 50 million miles (80 million kilometers) from Earth. The asteroid's orbit is well-defined and for at least the next 100 years, it will not come closer to Earth than 15 million miles (24 million kilometers).