In this situation, we don’t want to keep our enemies closer!
In an effort to protect Earth from humanity-ending asteroids and comets, astronomers first need to know where these giant objects are located in our solar system. It is for this reason that NASA developed and re-launched its Near-Earth Object Wide-field Survey Explorer (NEOWISE) spacecraft in December 2013 to discover, track, and characterize asteroids and comets that approach closest to Earth.
Now, after its second year of surveying, NASA is sharing what it has found.
Since the mission began, NEOWISE has recorded a total of 439 Near-Earth Objects (NEOs). However, 72 of these, which were not yet known to astronomers, were discovered last year. According to NASA, NEOs are asteroids and comets that have been nudged by the gravitational attraction of the giant planets in our solar system into orbits that bring them into Earth’s neighborhood.
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Eight of the objects discovered in the past year have been classified as potentially hazardous asteroids (PHAs), based on their size and how closely their orbits approach Earth. But that is no reason to panic.
NEOWISE has measured more than 19,000 asteroids and comets at infrared wavelengths using infrared sensitive cameras. And after in-depth analyses of over 5.1 million images, the researchers found that 439 of those were NEOs, while just eight were PHAs — a very small number in the grand scheme of things.
"By studying the distribution of lighter- and darker-colored material, NEOWISE data give us a better understanding of the origins of the NEOs, originating from either different parts of the main asteroid belt between Mars and Jupiter or the icier comet populations," said James Bauer, the mission’s deputy principal investigator at NASA's Jet Propulsion Laboratory in Pasadena, California, in a media release.
Originally, this mission was called the Wide-field Infrared Survey Explorer (WISE), which was launched in December 2009. However, it was placed into hibernation in 2011 after it completed its primary mission. Once it was given a new name and mission, it was reactivated in 2013 to assist NASA’s efforts to identify a population of potentially hazardous NEOs.
But the spacecraft isn’t the only technology being used to keep our eyes to the skies — it is just one piece of a really large network.
"NEOWISE discovers large, dark, near-Earth objects, complementing our network of ground-based telescopes operating at visible-light wavelengths. On average, these objects are many hundreds of meters across," Amy Mainzer of NASA’s Jet Propulsion Laboratory and NEOWISE principal investigator, said in the release.
NEOWISE will continue its mission of searching for NEOs, which will hopefully give researchers a heads up to any potentially Earth-destroying comets or asteroids. But let’s hope nothing is on route to hit us anytime soon.
Are you curious about how crowded our solar system actually is? NASA created this video, showing all the asteroids and comets spotted by NEOWISE since its launch.
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