Near-miss Halloween Asteroid Would Have Blasted a Hole Six Miles Wide

Meteor Crater, 1-kilometer-wide hole created by a much smaller asteroid

Meteor Crater, 1-kilometer-wide hole created by a much smaller asteroid

NASA discovers too late a 600-meter high-speed asteroid coming toward Earth, says not to worry because it’s going to miss anyway…maybe use a tractor beam next time

By Robin Rowe

HOLLYWOOD, CA (Gosh!TV) 2015/10/27 – “The close approach of 2015 TB145 at about 1.3 times the distance of the moon’s orbit, coupled with its size, suggests it will be one of the best asteroids for radar imaging we’ll see for several years,” said JPL asteroid research program manager Lance Benner, of JPL in a NASA announcement. “We plan to test a new capability to obtain radar images with two-meter resolution for the first time and hope to see unprecedented levels of detail.”

While it may be a bonanza for scientists, it’s not reassuring that  we had short notice that such a lethal object is passing by. Long ago Arizona was hit with a 50-meter asteroid. That punched a kilometer-wide hole at Meteor Crater. TB145 is much bigger.

Asteroid 2015 TB145 is a 600m-wide rock, more than a thousand times bigger by volume than the rock that hit near Flagstaff 50,000 years ago during the Pleistocene epoch, Instead of a crater one kilometer wide like Meteor Crater, a rock this size could make a 6-mile-wide hole, the size of a small city. The explosion could devastate an area the size of a small state. An ocean impact would create waves hundreds of feet tall.

Because TB145 is moving at 78,000 miles per hour, much faster than a typical asteroid, it would have less time to burn up in the atmosphere and hit harder in an impact event.

Because of it’s unusual orbit and speed, TB145 may not be a rocky asteroid at all. It could be the remnant of an icy comet.

Fortunately TB145 will pass by at a distance a bit farther than the moon.

If we needed to defend ourselves from TB145, there are a couple approaches that could be taken. The ICBM approach would try to break it into smaller pieces.

Breaking it into smaller meteorites might do more harm than good and might not work at all. It’s temping to think of using a nuke, but pieces of radioactive debris would come streaming toward Earth. And it could be tough to break with explosives. The rock that hit Meteor Crater was a big chunk of iron.

A better approach is to deflect the asteroid using a tractor beam. We may not have any Star Trek tractor beams, but the mass of even a small object traveling next to an asteroid will gently move it. A spacecraft traveling next to an asteroid can gently nudge it off a collision course. Doing that would require years of preparation, more than the two weeks of warning we had for TB145.

Note: The original version of this story gave an estimate of a 500m asteroid blasting a 6-mile-wide crater. Taking into account that the asteroid is 20% larger than first estimates and considering its high speed, a more accurate estimate is an 8-mile-wide crater.

To calculate the impact effects yourself, use the asteroid impact calculator the UK Imperial College Earth Impact Effects Program.

Halloween Asteroid Impact Estimate

Distance from Impact: 161.00 km ( = 100.00 miles )
Projectile diameter: 600.00 meters ( = 1970.00 feet )
Projectile Density: 3000 kg/m3
Impact Velocity: 35.00 km per second ( = 21.70 miles per second )
Impact Angle: 45 degrees
Target Density: 1500 kg/m3
Final Crater Diameter: 13.1 km ( = 8.14 miles )
Final Crater Depth: 642 meters ( = 2110 feet )

Meteor Crater Impact Estimate

For comparison, run these numbers in the asteroid impact calculator…

Distance from Impact: 161.00 km ( = 100.00 miles )
Projectile diameter: 40.00 meters ( = 131.00 feet )
Projectile Density: 8000 kg/m3
Impact Velocity: 20.00 km per second ( = 12.40 miles per second )
Impact Angle: 45 degrees
Target Density: 2500 kg/m3
Final Crater Diameter: 1.18 km ( = 0.73 miles )
Final Crater Depth: 250 meters ( = 821 feet )

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