Hey! Happy Saturday! Everything going well? Nice, nice. Sorry to piss in your cheerios butttttttttttt, did you know the number of asteroids that pose a risk to Earth is twice what we previously thought? Hey, have fun mowing your lawn.
The Earth is at risk from more asteroids than previously thought, according to a new survey. New data from the asteroid-tracking NEOWISE mission reveals that twice as many asteroids as previously thought are on low-inclination orbits that could bring them into contact with our home planet.
“We were very surprised to find that,” says Amy Mainzer of the Jet Propulsion Laboratory in Pasadena, California. “We were not expecting to find [that result] at all.”
NEOWISE, which took data with NASA’s infrared WISE space telescope from 2010 to 2011, has completed the most accurate census yet of potentially hazardous asteroids: those that come within 8 million kilometres of Earth, and are large enough to survive the trip through the atmosphere.
Because WISE searched in infrared wavelengths, it was equally as sensitive to large dark asteroids as to small bright ones. Previous surveys that looked only at visible light couldn’t tell those two populations apart, Mainzer says.
Mainzer and colleagues sampled 107 potentially hazardous asteroids (a representative sample of the entire population) and extrapolated to predict the total number. They found that about 4700 of them — give or take 1500 — are 100 metres or larger in diameter. Only 20 to 30 per cent of these have actually been observed.
Twice as many of those as previously thought are on so-called low-inclination orbits, which means they are closely aligned with Earth’s orbit and therefore have a higher chance of hitting us.
“It’s easier for them to make close approaches to the Earth more often,” Mainzer says. “It’s a hazard and a risk.”
It could be worse. Uh. Yeah.