NASA Just Gave Us 10 Good Reasons to Hunt For Near-Earth Asteroids

And Czech scientists give us at least a few more.

By MIKE MCRAE
Alexyz3d/Shutterstock

Our Solar System suddenly feels a little more cluttered, with NASA's Near-Earth Object mission having just released a year's worth of survey data, putting a bunch of new space rocks on our radar.



Most of the asteroids, comets, and general clumps of cosmic dandruff are too far away to be considered a threat to our planet, but NASA will be sure to keep a close eye on 10 objects that thinks could be big and near enough to be considered a hazard.

As the name suggests, NASA's Near-Earth Orbit Wide-field Infrared Survey Explorer (NEOWISE) is an orbiting telescope that looks for objects in our Solar System with orbits that could bring them close to our planet.

In 2010, NASA's Wide-field Infrared Survey Explorer spacecraft ran low on coolant for its telescope, so researchers scaled down the mission to scan the skies closer to home rather than looking all over the cosmos.

After entering a brief two-year nap in 2011, the spacecraft was reactivated, and has since characterised a total of 693 near-Earth objects. Of those, 114 had never been seen before.

This past year alone, NEOWISE has discovered 5 new comets, 64 main belt asteroids, and 28 near-Earth objects.

It found these by using its low infra-red bandwidth telescope to snap 2.6 million images of the sky.

A new technique called tail-fitting has now allowed researchers to use the database of images to model comet behaviour as they sweep through the Solar System.

"Comets that have abrupt outbursts are not commonly found, but this may be due more to the sudden nature of the activity rather than their inherent rarity," says Emily Kramer from NASA's Jet Propulsion Laboratory (JPL) in California.

"It is great for astronomers to view and collect cometary data when they find an outburst, but since the activity is so short-lived, we may simply miss them most of the time."

To get some idea of the total number of objects out there, take a look at the video clip below, which shows the orbits of asteroids in grey, near-Earth objects in green, and comets in yellow:






But what about those 10 potentially hazardous asteroids (PHA)? Is it time to invest in silver and wait out the fireball in grandpa's bunker?

PHAs are classified as asteroids that have a minimum orbit intersection distance of 0.05 astronomical units (1 AU is the distance from Earth to the Sun, so 0.05 AU is about 7.5 million kilometres, or 4.6 million miles).

They also must be big enough to have an absolute magnitude of 22 or brighter, which would make them bigger than 140 metres (around 500 feet) in size, assuming they were reflective enough.

Read more on ScienceAlert.

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