Dark Asteroids, Possible Threat to Earth

Comet Lunin Credit : Gustavo Muler /Observatory Nazaret


NASA's Wide-field Infrared Survey Explorer, had the mission to  search for "dark" objects in space like brown dwarf stars, vast dust clouds, and Earth-approaching asteroids. 

WISE scanned the entire celestial sky in infrared light about 1.5 times. It captured more than 2.7 million images of objects in space, ranging from faraway galaxies to asteroids and comets close to Earth. 

Most of the asteroids WISE found were in the main asteroid belt between Mars and Jupiter, but a fraction of them are different—they're the kind of Earth-approaching asteroids that can cause regional or global damage.


WISE tracked each potentially hazardous near-Earth object (NEO) it finds every three hours for up to 30 hours and then produces a "short track" predicting where it will be for the next few weeks. The WISE team sends all of this information to the NASA-funded Minor Planet Center in Boston. They post it on a publicly available NEO confirmation page, where scientists and amateur astronomers alike can continue to track the asteroid. 

The mission discovered previously unknown objects include 20 comets, more than 33,000 asteroids in the main belt between Mars and Jupiter, and 134 near-Earth objects (NEOs). Including some  by sensing their heat in the form of infrared light most other telescopes can't pick up.

What kind of NEOs are a treath?

The asteroid that is thought to have wiped out the dinosaurs was big--about 6 miles or 10 km in diameter. The chances of a similar hit in modern times are almost non-existent, but that doesn't mean we're out of the woods. Smaller asteroids are fairly common, and they could do damage, too, in the rare event of impacting the Earth. As recently as 1908, for instance, an asteroid some tens of meters across exploded over Tunguska, Russia, wiping out eight hundred square miles of remote forest.

"Regional damage from a small asteroid strike can be very serious indeed," says Ned Wright, principal investigator for WISE and a physicist at the University of California in Los Angeles. - "We need to keep surveying the skies to find these NEOs and precisely measure their orbits. If we can find the really dangerous asteroids early enough, we might have time to figure out how to deal with them."

Many telescopes on Earth are already searching. Notable programs include LINEAR, the Catalina Sky Survey and others.

Working together over the years they have found more than a thousand potentially hazardous asteroids.

On Febryary 17th The WISE Spacecraft transmitter was turned off for the final time at 12:00 noon PST  WISE Principal Investigator Ned Wright sent the last command. The Spacecraft will remain in hibernation without ground contacts awaiting possible future use.




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