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Space Science

Asteroid Apophis Just Got Bigger 182

Posted by samzenpus
from the a-little-chin-music dept.
astroengine writes "As the potentially hazardous asteroid makes closest approach to Earth today, astronomers using the European Herschel Space Observatory have announced something a little unsettling: asteroid 99942 Apophis is actually bigger than we thought. Herschel astronomers have deduced that Apophis is 1,066 feet (325 meters) wide. That's 20 percent larger than the previous estimate of 885 feet (270 meters). 'The 20 percent increase in diameter, from 270 to 325 m, translates into a 75 percent increase in our estimates of the asteroid's volume or mass,' said Thomas Müller of the Max Planck Institute for Extraterrestrial Physics in Garching, Germany, and lead scientist of the study. In addition, the space telescope has re-analyzed the albedo of the space rock, providing a valuable heat map of the object's surface — data that will improve orbital trajectory models."
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Asteroid Apophis Just Got Bigger

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  • 2029 approach (Score:5, Informative)

    by olsmeister (1488789) on Wednesday January 09, 2013 @09:45PM (#42541193)
    They're also saying that Apophis will pass within 36,000 km of Earth in 2029. [phys.org] Now that's not missing us by much.
  • Re:2029 approach (Score:5, Informative)

    by SternisheFan (2529412) on Wednesday January 09, 2013 @10:03PM (#42541347)

    They're also saying that Apophis will pass within 36,000 km of Earth in 2029. [phys.org] Now that's not missing us by much.

    And that'll be about the right time for our space-tech to have caught up enough for us to be able to 'lasso' it. If we miss it then, by it's expected return in 2036 we'd better be able to control it. It seems to keep getting a little closer with each return orbit.

    From the above link:

    " The asteroid will return to Earth's neighbourhood again in 2036, but quite how close it will come then is uncertain, as the 2029 approach is predicted to alter its orbit substantially. Obtaining improved physical parameters for Apophis and its orbit is thus of great importance in being able to make better predictions of its future trajectory." Read more at:

  • Re:2029 approach (Score:5, Informative)

    by Sowelu (713889) on Wednesday January 09, 2013 @10:06PM (#42541361)

    For those who are hoping to see it, that distance puts it at two arcseconds wide (if my calculations are decent). This is roughly the same width in the sky as Neptune, or 900 times smaller diameter than our moon on an average day.

  • by Anonymous Coward on Wednesday January 09, 2013 @10:58PM (#42541779)

    you know the amateur astronomers that discovered 'Aphophis' were big stargate fans, hence the name. SG1 reference built-in from the start.

  • Re:Wait a minute (Score:4, Informative)

    by Daetrin (576516) on Wednesday January 09, 2013 @11:27PM (#42542013)
    Well first of all, they successfully predicted it would be here now, so they must have done something right.

    The issue is that mass is irrelevant when you're measuring how something is affected by gravity. This was the point of the (possibly apocryphal) experiments of Galileo. The force of the gravity on the object is proportional to the mass of the object, but the force needed to move the object is also proportional to its mass, so it all cancels out. Apophis will continue to follow the same path, no matter what its mass is.

    Now technically speaking the weight of the object does affect the rate at which other things fall towards it. (If you drop a 2kg weight the earth "falls" upwards twice as fast as if you drop a 1kg weight, but the difference is obviously too small to be measured.) So if Apophis encounters an object close to or smaller than its own mass it will make a difference. However i'm pretty sure they aren't able to predict encounters with objects that small, so if it does happen it will be a totally unexpected event with an unknown affect on its orbit anyways.
  • by Smallpond (221300) on Wednesday January 09, 2013 @11:35PM (#42542087) Homepage Journal

    Once it's going away, how would we catch it? It'll be going 25 km/sec relative to us.

  • by Anonymous Coward on Thursday January 10, 2013 @02:51AM (#42543195)

    The orbit of Apophis ranges between 0.7 and 1.1 AU from the sun. In that range, there aren't any large objects it could encounter that we don't already know about. The major uncertainties in its projected orbit are from gravitational perturbations from the outer planets, sunlight pressure, etc., which are fairly well understood: it's quite certain that it won't hit the Earth in 2029.

    However, the encounter with the Earth in 2029 will put Apophis in a new orbit, which depends quite sensitively on how closely it passes us. If it passes us at just the right distance (within a window of 800 m), its new orbit would hit the Earth in 2036. That's the plausible threat from Apophis - though, based on current measurements, there's about a 1-in-7,000,000 chance that it'll happen.

  • by osu-neko (2604) on Thursday January 10, 2013 @04:25AM (#42543547)

    ...I think euthanasia may be appropriate in certain situations, but not when you can put the minds of a couple of expert trauma surgeons into some of the crew and just cut the patients legs off, or waste some explosives to try and remove the debris, or send the ships robot down to the surface to move the debris, or any of a dozen ideas better than just having a few soldiers try to muscle the debris off.

    None of these options were possible at the time.

    When a patient is in extreme chronic pain that can't be stopped and will last for the rest of their life and begs to die, it's time to consider euthensia.

    That would be exactly the situation here. The only options were to either euthanize him, or leave him there in pain to die alone. He asked for the former, and got it.

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