June 25, 2013
Hawaiian Telescope Discovers Ten Thousandth Near-Earth Object
Lee Rannals for redOrbit.com – Your Universe Online
Astronomers spotted asteroid 2013 MZ5 on the night of June 18, marking a significant milestone for the NEO search. The space agency said 90 percent of all NEOs discovered were first detected by NASA-supported surveys.
"But there are at least 10 times that many more to be found before we can be assured we will have found any and all that could impact and do significant harm to the citizens of Earth," said Lindley Johnson, program executive for NASA's Near-Earth Object Observations Program at NASA Headquarters, Washington.
In order to be classified as an NEO, a comet or asteroid must approach Earth at an orbital distance to within about 28 million miles. They range in size from as small as a few feet to as large as 25 miles for the largest NEO. Asteroid 2013 MZ5 is about 1,000 feet across and will never be close enough to Earth to be considered potentially hazardous.
"The first near-Earth object was discovered in 1898," said Don Yeomans, long-time manager of NASA's Near-Earth Object Program Office at the Jet Propulsion Laboratory in Pasadena, Calif. "Over the next hundred years, only about 500 had been found. But then, with the advent of NASA's NEO Observations program in 1998, we've been racking them up ever since. And with new, more capable systems coming on line, we are learning even more about where the NEOs are currently in our solar system, and where they will be in the future."
About 10 percent of the 10,000 NEOs discovered are larger than six-tenths of a mile, which is roughly the size that could produce global consequences if one struck Earth. However, NASA says its program has found that none of these larger NEOs currently pose an impact threat.
NASA said scientists predict there to be about 15,000 NEOs that are one-and-a-half football fields in size, or 480 feet. There could be more than a million NEOs that are about one-third of a football field in size. An NEO hitting Earth would need to be about 100 feet or larger in order to cause significant damage in a populated area. The space agency said less than one percent of the 100-foot-sized NEOs have been detected.
"These days we average three NEO discoveries a day, and each month the Minor Planet Center receives hundreds of thousands of observations on asteroids, including those in the main-belt," said Tim Spahr, director of the Minor Planet Center. "The work done by the NASA surveys, and the other international professional and amateur astronomers, to discover and track NEOs is really remarkable."
Earlier this month, NASA announced a grand challenge focused on finding all asteroid threats to human populations. This "Great Challenge" asks citizen scientists, along with industry professionals, to focus on detecting and characterizing asteroids and learn how to deal with potential threats.
"We will also harness public engagement, open innovation and citizen science to help solve this global problem," said NASA Deputy Administrator Lori Garver.
The space agency also invited industry and potential partners to offer up some ideas on accomplishing NASA's goals to locate, redirect and explore an asteroid.