NASA space telescope quickly spots first asteroid
- — 26 January, 2010 14:13
Almost as soon as it came online, NASA’s Wide-field Infrared Survey Explorer has spotted a new, little over mile wide asteroid some 98 million miles from Earth.
The near-Earth object, designated 2010 AB78 and circles the Sun in an elliptical orbit tilted to the plane of our solar system. The object comes as close to the Sun as Earth, but because of its tilted orbit, it will not pass very close to Earth for many centuries. This asteroid does not pose any foreseeable impact threat to Earth, but scientists will continue to monitor it.
WISE spotted AB78 Jan. 12 as it circled the Earth and observed the asteroid several times during a period of one-and-a-half days before the object moved beyond its view. Researchers then used the University of Hawaii’s 2.2-meter (88-inch) visible-light telescope near the summit of Mauna Kea to follow up and confirm the discovery, NASA said. There is no danger of the newly discovered asteroid hitting Earth, NASA noted.
NASA said WISE has already opened a firehouse of space information and said more asteroid and comet detections will be forthcoming. The observations will be sent to the clearinghouse for solar system bodies, the Minor Planet Center in Cambridge, Mass., for comparison against the known catalog of solar system objects. A community of professional and amateur astronomers will provide follow-up observations, establishing firm orbits for the previously unseen objects, NASA said.
The WISE spacecraft in December successfully popped the cover off its infrared telescope and began what NASA called a"celestial treasure hunt" mission of sending back what will be millions of images of space. The first WISE infrared image was taken shortly after the space telescope's cover was removed, NASA said.
In January WISE, has captured its first image showing the over 3,000 stars in the Carina constellation.
The initial image - which was taken while the spacecraft was staring at a fixed patch of sky and is being used to calibrate the spacecraft's pointing system -- covered a patch of space about three times larger than the full moon, NASA stated.
The area was selected because it does not contain any unusually bright objects, which could damage instrument detectors if observed for too long, NASA stated. The "first-light" picture shows thousands of stars and covers an area three times the size of the moon. WISE takes about 7,500 images a day, NASA stated.
WISE will spend six months – about through May -- mapping the whole sky. It will then begin a second scan to uncover even more objects and to look for any changes in the sky that might have occurred since the first survey, according to NASA. This second partial sky survey will end about three months later when the spacecraft's frozen-hydrogen cryogen runs out. Data from the mission will be released to the astronomical community in two stages: a preliminary release will take place six months after the end of the survey, or about 16 months after launch, and a final release is scheduled for 17 months after the end of the survey, or about 27 months after launch.
WISE observes infrared light, letting it show the darkest components of the near-Earth object population -- those that don’t reflect much visible light. Visible-light estimates of an asteroid’s size can be deceiving, because a small, light-colored space rock can look the same as a big, dark one. In infrared, however, a big dark rock will give off more of a thermal or infrared glow, and reveal its true size, NASA stated.
NASA said WISE is expected to find about 100,000 previously unknown asteroids in our main asteroid belt, a rocky ring of debris between the orbits of Mars and Jupiter. It will also spot hundreds of previously unseen near-Earth objects NASA said.
The asteroid topic is a hot one as the National Research Council last week issued a report -- “Defending Planet Earth: Near-Earth Object Surveys and Hazard Mitigation Strategies" -- that said NASA needs to do way more to detect asteroids.
The report said combinations of space- and ground-based telescopes may be the most economically palpable defenses NASA can mount against asteroids and comets heading toward Earth, but there are more advanced defenses involving spacecraft and nuclear explosions that might be plausible in the future.
The report says the $4 million the US currently spends annually to search for comets and asteroids is insufficient to meet a congressionally mandated requirement on NASA to detect NEOs that could threaten Earth.
The report states that while impacts by large comets or asteroids are rare, "a single impact could inflict extreme damage, raising the classic problem of how to confront a possibility that is both very rare and very important. Far more likely are those impacts that cause only moderate damage and few fatalities."
An asteroid or comet about 10 kilometers in diameter struck the Yucatan peninsula 65 million years ago and caused global devastation, probably wiping out large numbers of plant and animal species including the dinosaurs, the report states.
Objects as large as that strike Earth only about once every 100 million years on average, the report notes. NASA has been highly successful at detecting and tracking objects 1 kilometer in diameter or larger, and continues to search for these large objects. The report notes that NASA has managed to accomplish some of the killer asteroids mandate with existing telescopes but with over 6,000 known objects and countless others the task is relentless.