#Asteroids #Earth – Protecting Earth From Killer Asteroids: Neowise Detects 114 Near Earth Objects, 10 Potentially Hazardous : The danger of potentially hazardous near-Earth objects is well known, and NASA reactivated the WISE telescope in September, 2013, to help in the tracking of known objects and the detection of those heretofore unknown potentially hazardous asteroids — commonly referred to by the media as “killer asteroids” — that have gone undetected. This week, NASA announced that the repurposed telescope, dubbed NEOWISE, had found 114 previously unknown near-Earth objects, and nearly a hundred of those have been discovered in just the last year.
Space described the large number of detected near-Earth objects — and the data gathered on nearly 600 more asteroids, comets, and other space objects already catalogued — as a “treasure trove,” noting that the NEOWISE (Near-Earth Object Wide-field Survey Explorer) mission has only been in operation for three-and-a-half years. Of the 114 unknown near-Earth objects NEOWISE has found, 97 of them have been discovered in just the last 12 months.
“NEOWISE is not only discovering previously uncharted asteroids and comets, but it is [also] providing excellent data on many of those already in our catalog,” NEOWISE principal investigator Amy Mainzer of NASA’s Jet Propulsion Laboratory (which oversees the mission) in Pasadena said in a statement. “It is also proving to be an invaluable tool in the refining and perfecting of techniques for near-Earth object discovery and characterization by a space-based infrared observatory.”
Near-Earth Objects (NEOs), as defined by NASA, are asteroids and comets that have been guided “by the gravitational attraction of the planets in our solar system into orbits that allow them to enter Earth’s neighborhood.”
Potentially Hazardous Asteroids (PHAs) are objects that could cause significant regional damage on impact if they were to proceed unabated to Earth. They are at least 140 meters (359 feet) in diameter. Congress made finding large asteroids a priority in 2005 when it passed the George E. Brown, Jr. Near-Earth Object Survey Act, which gave authorization to NASA to “establish a program to detect, track, catalogue, and characterize the physical characteristics of near-Earth asteroids and comets equal to or greater than 100 meters in diameter in order to assess the threat of such near-Earth objects in striking the Earth.”
The law charged NASA to carry out its mission in order to “provide warning and mitigation of the potential hazard” presented by the PHAs.
Thus far, according to NASA statistics, it is estimated that over 90 percent of the near-Earth objects larger than one kilometer have been discovered. The NEO Program is now engaged in finding what they believe is 90 percent of the NEO population — those objects larger than 140 meters.
Currently, most of the near-Earth objects detected are picked up by the NEO surveys Catalina Sky Survey in Tucson, Arizona, and the Panoramic Survey Telescope & Rapid Response System (Pan-STARRS) in Hawaii.
In hard numbers, catalogued NEOs hit the 15,000 plateau in October, according to a NASA statement issued at the time.
Using NEOWISE data, NASA estimates that there are between 3,200 to 4,700 PHAs. Of them, only about 20 to 30 percent have been discovered.
“While no known NEO currently poses a risk of impact with Earth over the next 100 years,” said NASA Planetary Defense Officer Lindley Johnson, “we’ve found mostly the larger asteroids, and we have a lot more of the smaller but still potentially hazardous ones to find.”
The operative term in the statement, of course, is “known.” But regardless if the potentially hazardous space rock is known or unknown, there is no planetary defense system in place to defend the Earth from a potential strike by one.
Scientists have been attempting to issue a call to arms for years, all to no avail, the danger lacking in apparent urgency. This past December, at a conference in San Francisco, NASA scientist Joseph Nuth told the gathering, according to the Inquisitr, that Earth was overdue for a “dinosaur killer” asteroid and, if one were to be discovered that would arrive inside a couple years, there was “not a hell of a lot we can do about it at the moment.”