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Space Science

Asteroid Apophis Just Got Bigger 182

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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  • So... (Score:5, Interesting)

    by Anonymous Coward on Wednesday January 09, 2013 @09:42PM (#42541153)

    ...does this mean we're more likely to die or less likely to die?

  • Homeowners insurance (Score:3, Interesting)

    by AndyKron ( 937105 ) on Wednesday January 09, 2013 @09:57PM (#42541295)
    Will my homeowners insurance cover any damage should this hit, or would it be considered "an act of God"?
  • Re:2029 approach (Score:5, Interesting)

    by Daniel Dvorkin ( 106857 ) on Wednesday January 09, 2013 @10:15PM (#42541429) Homepage Journal

    It's a lot easier to calculate orbit than mass, and the latter is pretty much irrelevant to the former--Earth is so much more massive than Apophis can possibly be that the asteroid's mass can be ignored in any orbital calculation. So we'll know if it's going to hit us or not, even if we don't know how big a boom it will make if it does hit.

  • Re:Wait a minute (Score:3, Interesting)

    by VortexCortex ( 1117377 ) <VortexCortex.project-retrograde@com> on Wednesday January 09, 2013 @11:33PM (#42542075)

    So we used our super advanced technology to know precisely where this asteroid will be in like 2042 or whatever but we were off by almost half its mass (or volume)? Anyone see a little disconnect there? Especially since other solar system bodies' gravitational fields will affect it differently if it weighs double what we thought. I knew it was a load of alarmist, headline-grabbing BS.

    So, re-read what you said and think about that. You'll come to the conclusion that you should be quite alarmed because we don't know what might hit us when. We also didn't know about Eris, a proto-planet more massive than Pluto until 2005. That means we're pretty damn blind, and that stuff we can see we can't see very well and thus can't make very precise predictions about them.

    If anything, to me that means we should be pretty concerned about this situation and seek to rectify it ASAP. We need to swap the NASA and armed force's budgets. Get some space infrastructure in place to protect us from other asteroids: Get a few big rocks of our own orbiting to use as slingshots or gravity tugs, etc; Much better telescopes, esp. wide field systems; Self sustaining colonies off-world so all our eggs aren't in one basket. We can squabble about Oil after we're sure we're not going to be extinct.

    The dinosaurs regarded chicken little as an Alarmist when she saw a meteor shower and said the sky was falling. Turns out she was right, only the dinosaurs in the flight program survived.

  • Re:So... (Score:5, Interesting)

    by Anonymous Coward on Wednesday January 09, 2013 @11:43PM (#42542149)

    Only about 95% of all humans who have ever existed have died. There's still a 5% fighting chance immortality exists. Not only that, but my odds are better than most humans, past and present.

  • Re:Wait a minute (Score:5, Interesting)

    by arth1 ( 260657 ) on Thursday January 10, 2013 @01:38AM (#42542879) Homepage Journal

    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.

    True, but a higher mass relative to the diameter means that solar winds have a lesser effect. Granted, that effect is small compared to the pull of Earth, Sol, Jupiter and (when close) Luna, but it might still be significant in calculating whether we're going to get hit or not.

  • Re:2029 approach (Score:4, Interesting)

    by Anonymous Coward on Thursday January 10, 2013 @06:34AM (#42544005)

    "The real probability"? I suppose then the "real probability" of you buying a winning lottery ticket, or rolling 6 twenty consecutive times, etc, etc, are all 0 or 100% too.

    Yes, actually. That's what probability really is.
    It is not the event itself which is uncertain, but rather our knowledge of the event. In this type of situation, if we make a GUESS, the probability tells us how likely we are to have guessed correctly.

    Think about it like this. Take out a deck of cards, shuffle it, and set it face down. There is a card on the top. If you say the name of a card out loud, you have a 1/52 chance of saying the card which is actually on top. We can consider the actual value of that card to be uncertain from a mathematical point of view, but in reality its value is already fixed- you just don't know the value.

    In regards to the lottery ticket, we actually know a little bit more. If you do not purchase a ticket at all, we CAN say with 100% certainty that you do not hold the winning ticket. If you DO purchase a ticket, we cannot say for certain if you have the winning ticket or not, but the reality is that either you have a winning ticket, or you do not.

    The problem with your line of thinking is that you are confusing a prediction with an actuality. We use probability to determine future events when we have incomplete knowledge, once our knowledge of ALL factors which influence the event is complete, then it is no longer an unknown and we can say the event either will, or will not, occur. Or put another way, if you have access to all the data you're not predicting, you're simply calculating a result.

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