Space

Space agencies track trajectory of approaching asteroid

Space agencies track trajector...
The asteroid 2012 TC4 (circled) has been detected as it approaches Earth - this image is a composite of 37 individual exposures to compensate for its motion, causing the stars around it to appear as streaks
The asteroid 2012 TC4 (circled) has been detected as it approaches Earth - this image is a composite of 37 individual exposures to compensate for its motion, causing the stars around it to appear as streaks
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The asteroid 2012 TC4 (circled) has been detected as it approaches Earth - this image is a composite of 37 individual exposures to compensate for its motion, causing the stars around it to appear as streaks
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The asteroid 2012 TC4 (circled) has been detected as it approaches Earth - this image is a composite of 37 individual exposures to compensate for its motion, causing the stars around it to appear as streaks

Asteroid 2012 TC4 hasn't been seen since its last brush with our planet five years ago, but calculations of its trajectory told astronomers that it would return in October 2017. Right on cue, the building-sized rock has now emerged from the darkness of space as it hurtles towards the Earth. NASA and the ESA plan to use it as a test run for the international Planetary Defense network, and have now been able to calculate its trajectory.

With asteroids grazing past Earth with worrying regularity, it would definitely pay to have some forewarning if any were on a collision course. The Chelyabinsk meteor is a perfect example of a hazardous space rock sneaking up on us, causing widespread damage and injury when it exploded over Russia in 2013. To help prevent a disaster like that (or worse) from occurring again, NASA has established the Planetary Defense Coordination Office to detect and track near-Earth objects.

Knowing exactly when TC4 would return makes it a perfect candidate for testing the equipment and infrastructure of that system, and NASA, ESA and other institutions set up the 2012 TC4 Observing Campaign to determine its orbit more precisely. Previous calculations could only be sure that it would pass within a window of 4,200 to 170,000 miles (6,760 to 274,000 km) of Earth, and its size couldn't be precisely pinned down.

This time around, the asteroid was spotted on July 27 by ESA astronomers using the Very Large Telescope Observatory in Chile, before further observations on July 31 and August 5 confirmed its identity as TC4. Its brightness at this distance tells the team that its diameter is about 15 m (49 ft).

Based on these observations, the astronomers have determined that TC4 will pass within 50,100 km (31,130 miles) of Earth at 5:41 Universal Time on October 12, 2017. That's 13 percent of the distance between the Earth and the Moon.

Astronomers report that viewing conditions will remain clear over the next few months as TC4 approaches, allowing them to gather more data for this and other near-Earth objects. Then, like last time, it should vanish into the darkness again almost immediately after it passes.

Sources: NASA, University of Maryland

11 comments
Ross Jenkins
Would it be possible to place some sort of tracking device to the asteroid? Maybe a mirror of some sort that would reflect a certain band of light. Or maybe something powered. My only concern would be that by attaching something to the asteroid would in a small way change it gravity center, adding to its mass and possibly effecting its orbit in a way that would bring it closer to earth on a future approach.
CharlieSeattle
Attach a nuke to it with a time delay and detonate it later far out in space near a gas giant planet that can suck up the fragments.
Bruce Golden
Ross ... good idea and good concern...TC4 is pretty small so anything we might place would necessarily need to be large relative to the object...would take energy supply and tracking to support a useful mirror...same energy could easily power a radio beacon...maybe a radio beacon and a star tracker that could observe and report IC4's position...its spin is an issue for whatever...maybe best to coat TC4 with reflective coating that our bigger telescopes could "see" at much greater distances...probably talking about $200MM to build the Lander carrying whatever technology and $100-250MM for the launch...is in general range of Russian airburst so 500kt risk...
Michael Z. Williamson
Charlie: It doesn't need a nuke. Any small charge would change its trajectory, or even painting one side to reflect or absorb sunlight would mean it would gradually have enough energy change to adjust its orbit. The question then is what does the orbit adjust to? It might become more of a risk.
Captain Danger
Sounds like a good time to test how nukes work in space At this point we should be able to vaporize a 50 foot wide rock. It would also be a nice demo for our friends in N. Korea.
Douglas Bennett Rogers
These asteroids could become a resource by being converted into Orion-style space ships. Instead of destroying them with nuclear explosives the explosives should power them and reprocess them into habitable structures.
James P
They say they want to track them to make sure we won't be hit but..... Do you really think they would tell us if we were going to get hit? Why would they? It would just cause mass panic, rioting, thieving, etc. I think they would put the government in underground shelters and let the rest of us fend for ourselves. Just my opinion.
roger35
Article says: "To help prevent a disaster like that (or worse) from occurring again, NASA has established the Planetary Defense Coordination Office to detect and track near-Earth objects." I seriously doubt detecting and predicting a collision can prevent a disaster. Maybe if predicted to hit the ocean there will be time to evacuate some of the coastlines from the resulting tsunami. But it will be a disaster.
neutrino23
The fear is that we'll see some large asteroid just a short time before it strikes the earth. The hope is that we'll discover them years in advance which would give us time to slightly change their orbit so that they don't strike the earth. The farther in advance we learn of them the less effort is needed to deflect their orbits.
Lamar Havard
It would be cool if we could launch a small thruster to intercept it and slow it down enough to be set in Earth orbit a little further away than the ISS. Then we could mine it for resources.