2012 TC4 will pass Earth well within the Moon's orbit a month from now, but not nearly as close as previously estimated:
Mark your calendar for Oct. 12. That's when asteroid 2012 TC4 will slip past Earth at an expected distance of around 27,300 miles (44,000 kilometers). The European Southern Observatory's Very Large Telescope in Chile recently caught sight of the asteroid, which could be up to 100 feet (30 meters) in size.
NASA is leading a coordinated international campaign to observe TC4. In July, NASA suggested the asteroid could squeeze in as close as 4,200 miles (6,800 kilometers), but the European Space Agency's latest estimates give us more breathing room.
Geostationary equatorial orbit (GEO) is at about 35,786 km above mean sea level.
Also at Phys.org (AFP).
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2012 TC4 has passed by Earth:
2012 TC4 is estimated to be 45 to 100 feet (15 to 30 meters) in size. Orbit prediction experts say the asteroid poses no risk of impact with Earth. Nonetheless, its close approach to Earth is an opportunity to test the ability of a growing global observing network to communicate and coordinate their optical and radar observations in a real scenario.
This asteroid was discovered by the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) on Hawaii back in 2012. Pan-STARRS conducts a near-Earth object (NEO) survey funded by NASA's NEO Observations Program, a key element of NASA's Planetary Defense Coordination Office. However, 2012 TC4 traveled out of the range of asteroid-tracking telescopes shortly after it was discovered.
Based on the observations they were able to make in 2012, asteroid trackers predicted that it should come back into view in the fall of 2017. Observers with the European Space Agency and the European Southern Observatory were the first to recapture 2012 TC4, in late July 2017, using one of their large 8-meter aperture telescopes. Since then, observers around the world have been tracking the object as it approaches Earth and reporting their observations to the Minor Planet Center.
This "test" of what has become a global asteroid-impact early-warning system is a volunteer project, conceived and organized by NASA-funded asteroid observers and supported by the NASA Planetary Defense Coordination Office (PDCO). As explained by Michael Kelley, program scientist and NASA PDCO lead for the TC4 observation campaign, "Asteroid trackers are using this flyby to test the worldwide asteroid detection and tracking network, assessing our capability to work together in response to finding a potential real asteroid-impact threat."
Previously: NASA Formalizes Planetary Defense Coordination Office to Track Asteroids
NASA and FEMA Conduct Asteroid Threat Response Exercise
Surprise Flyby of Asteroid on January 9, 2017
NASA to Redirect an Asteroid's Moon With Kinetic Impact
Asteroid 2012 TC4 Will Pass Close to Earth on October 12th
4.4 Kilometer Asteroid Safely Passes by Earth (two moons discovered)
(Score: 0) by Anonymous Coward on Saturday August 12 2017, @05:48PM (5 children)
What are the risks to Earth? Should we expect a Tunguska type of event?
(Score: 2) by takyon on Saturday August 12 2017, @05:52PM
If their calculations are correct, there is no risk to Earth because it won't pass through the atmosphere or impact the surface.
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(Score: 0) by Anonymous Coward on Saturday August 12 2017, @06:09PM
The main risk is that you will continue to be nickle and timed by nasa for these pr releases.
(Score: 2) by kaszz on Saturday August 12 2017, @07:03PM (2 children)
City killer size, though the speed at 14 000 m/s is high to the usual 4000 m/s. So if it hits it would wipe out a megacity. And at the distance of 44 000 km. I'll guess it won't get caught in the gravity field.
It is however a good reminder that our luck may run out.
(Score: 2) by takyon on Saturday August 12 2017, @08:07PM (1 child)
Asteroids of this size and high velocity can cause air bursts, although the angle of entry is a factor. This could be the same size as the Chelyabinsk meteor [wikipedia.org], which caused nearly 1,500 injuries but no deaths. That meteor traveled at 19,160 m/s.
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(Score: 2) by kaszz on Saturday August 12 2017, @09:26PM
Chelyabinsk were lucky as they were not directly hit.
(Score: 2) by HiThere on Saturday August 12 2017, @11:25PM (7 children)
I find it concerning that the prior orbit calculated was so wrong. This seems to imply that the other orbits they calculate might be equally wrong, and not necessarily in the same direction.
Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
(Score: 2) by kaszz on Sunday August 13 2017, @04:07AM (4 children)
Did you account for the distance to Earth? the closer a object gets. The more data for an accurate trajectory and less chance of disruptions.
(Score: 2) by HiThere on Sunday August 13 2017, @06:49PM (3 children)
No. Those making the projections are supposed to account for that. And the stories never give error bars, so I can't even say for certain if their earlier projection was wrong. Still, it sure *looks* as if it was wrong. They were off by over 20,000 miles, which would mean that if that was within their error bars, so was a direct central impact.
That said, yes, this kind of prediction is difficult and uncertain. But the prediction (as reported) wasn't "better keep an eye on this one", but rather "this one is going to miss us safely by this much". Which leads to a lack of trust in all the other predictions (as reported).
Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
(Score: 2) by kaszz on Monday August 14 2017, @03:48AM (2 children)
Actual policy if there IS an impact is to not tell the public to avoid public riots. Figure that.
I'll keep your point in mind though. There obviously seems to be a loophole.
(Score: 0) by Anonymous Coward on Monday August 14 2017, @06:47AM
[citation needed]
Like the leaky White House can keep it a secret anyway.
(Score: 2) by Justin Case on Monday August 14 2017, @04:51PM
Agree with AC. Citation?
(Score: 3, Interesting) by JoeMerchant on Sunday August 13 2017, @08:35PM (1 child)
I think they calculate cones, then quote the close side of the cone within some confidence interval... thus the news tends to get better most of the time.
🌻🌻 [google.com]
(Score: 3, Interesting) by Sulla on Monday August 14 2017, @09:54PM
When I was in college I had a lab class that took snapshots of rock locations and used a program to track the possible future locations. It did end up looking like an arcing cone. It was a pretty cool class and some of my classmates got their report published and got some sort of cool NASA acknowledgement for correctly predicting their rock hitting Mars. Mine did piss all forever hanging out in the belt.
Ceterum censeo Sinae esse delendam