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These 1,397 Asteroids Are Pretty Darn Close to Earth, But NASA’s Not Worried

Nearly every potential impact event in the next century qualifies as having “no likely consequences”

August 7, 2013

A map of those potentially hazardous objects (the Earth’s orbit is the third circle from the sun). Photo: NASA

There are around 1,400 potentially hazardous objects zipping around space, just waiting for the stars to align just so in order to send them hurtling on a direct path to the Earth. As Popular Science describes:

If it’s closer than 4.6 million miles away and larger than about 350 feet in diameter, NASA’s watching it. And if a comet or asteroid’s orbit comes close enough to ours that there’s some potential for it to collide with our planet, NASA classifies it as a PHO. If something that size smacked Earth, it’d cause a major tsunami (if it hit water) or major regional destruction (if it hit land).

And yet, though we’re situated in this seeming vortex of destruction, NASA isn’t overly concerned. And for good cause: NASA meticulously monitors these objects, both assessing the chances of an impact and the worst possible damage such an impact could have were it to transpire. The verdict: the planet is secure, at least so far as asteroids are concerned.

A risk evaluation NASA uses called the Torino Impact Hazard Scale calculates the maximum detected hazard of each of these potential events. Nearly every potential impact event in the next century qualifies as having “no likely consequences” or entails an object of 50 meters in diameter or less (asteroids need to be 140 meters in diameter to really pose a threat). Only one object, the 2007 VK184, registers at even the lowest reading on the Torino Impact Hazard Scale, at a measly 1. Meant to potentially strike between 2048-2057, the 2007 VK184 “merits careful monitoring,” according to NASA.

But that’s doesn’t faze the agency’s scientists. Here’s how they describes Torino objects at level 1:

A routine discovery in which a pass near the Earth is predicted that poses no unusual level of danger. Current calculations show the chance of collision is extremely unlikely with no cause for public attention or public concern. New telescopic observations very likely will lead to re-assignment to Level 0.

In other words, we are safe from space-delivered Armageddon. Those 1,400 objects make for a nice graphic, but the Earth will almost certainly persist asteroid-collision free for at least the next 100 years. Just in case the point needs reiteration, NASA further spells it out:

Being classified as a PHA does not mean that an asteroid will impact the Earth: None of these PHAs is a worrisome threat over the next hundred years. By continuing to observe and track these asteroids, their orbits can be refined and more precise predictions made of their future close approaches and impact probabilities.