Follow Slashdot blog updates by subscribing to our blog RSS feed

 



Forgot your password?
typodupeerror
Space Science

Nearby, Recent Interplanetary Collision Inferred 88

Posted by kdawson
from the when-worlds-collide dept.
The Bad Astronomer writes about a new discovery by the Spitzer Space Telescope, which detected signs of an interplanetary smashup only 100 light-years from here, and only a few thousand years ago. There's a NASA-produced animation of the collision between a Mercury-sized planet and a moon-sized impactor. The collision's aftermath was detected by the presence of what are essentially glass shards in orbit around the star. Here's NASA's writeup.
This discussion has been archived. No new comments can be posted.

Nearby, Recent Interplanetary Collision Inferred

Comments Filter:
  • by olsmeister (1488789) on Monday August 10, 2009 @07:41PM (#29018263)
    the guy posting the blog states: "the shock wave ring travels around the planet as shown, but when the ring converges on the point opposite the collision point, there would be a huge explosion and a vast plume of material launched into space. No one ever puts that in their animations"

    I thought the same thing when I watched the video - there would be a godawful explosion at the antipode
    • by JuzzFunky (796384) on Monday August 10, 2009 @08:10PM (#29018447)
      It is interesting that the animation shows a direct hit head on collision rather than a glancing blow. Most of matter from the planet and impactor seems to combine into a single mass. Would a glancing blow that shatters the impactor result in more debris?
      • by rrohbeck (944847)

        It is interesting that the animation shows a direct hit head on collision rather than a glancing blow. Most of matter from the planet and impactor seems to combine into a single mass. Would a glancing blow that shatters the impactor result in more debris?

        Yes. Remember that Earth-like planets are liquid blobs with a shell that's thinner than an egg's. A glancing blow would spray lots of debris out to one side. That's how the moon formed when Earth was hit 4 billion years ago.

    • by JohnnyDanger (680986) on Monday August 10, 2009 @08:22PM (#29018511)
      The impact on Mercury which created the Caloris basin caused some wacky geology at the antipodal point to the collision. This is called "chaotic" or "weird" terrain. Link [wikipedia.org].
      • by pintpusher (854001) on Monday August 10, 2009 @10:05PM (#29019153) Journal
        I immediately wondered if there were any such antipodal geology evident on earth. A quick google turned up this presentation [newgeology.us] which is pretty darn interesting. IANAGeologist, and can't speak to the accuracy of the claims, but it's still darn cool!
        • by sznupi (719324)

          ...and on a site of apparent supporter of most fringe proposals that are promoted by religious nutjobs or those that feel peer review is unfair.

          • yikes! I sure didn't do my homework. I should have looked around there some more. I certainly don't mean to promote such wackery. I am shamed.
        • by mykdavies (1369)
          I'd be wary of the quality of the interpretation and presentation of science on that site; from the homepage, Shock Dynamics is "A new geology theory featuring impact-powered rapid continental drift as an alternative to plate tectonics. The key to creation geology."
    • by symbolset (646467)
      I should imagine the kinetic enery would travel fastest in a direct line through the object, followed shortly later by the secondary shockwave effects. This would give more of a fountain eruption at the antipode, and more escaping ejecta. I can't wait until they get footage of this happening, rather than an animated model of what it might look like.
    • You mean worse than at the point of impact? ;)

  • by XPeter (1429763) *

    100 light-years! Boy that barely missed us, better put on your hardhats boys because the next mash up is said to be only 80 light-years away!

    • by TimSSG (1068536)

      100 light-years! Boy that barely missed us, better put on your hardhats boys because the next mash up is said to be only 80 light-years away!

      Yeah, but if it is in the opposite direction that is an average of a 10 light-years away.
      Tim S.

    • Re: (Score:3, Funny)

      by MichaelSmith (789609)

      100 light-years! Boy that barely missed us, better put on your hardhats boys because the next mash up is said to be only 80 light-years away!

      We should hope that whoever engineered this is not heading our way.

    • by Fluffeh (1273756)

      100 light-years! Boy that barely missed us, better put on your hardhats boys because the next mash up is said to be only 80 light-years away!

      WHOOSH.

      That's not the sound of you missing a joke. That's the sound of the planet flying above your head.

  • "Just what are you inferring?" *annoyed look*
  • by gmuslera (3436) on Monday August 10, 2009 @07:56PM (#29018363) Homepage Journal
    The civilization that was living in that planet is traveling to a little blue planet that was nearby at a modest 100 light years. Invasion is scheduled for next Tuesday.
    • Re: (Score:3, Funny)

      by INeededALogin (771371)
      The civilization that was living in that planet is traveling to a little blue planet that was nearby at a modest 100 light years. Invasion is scheduled for next Tuesday.

      Little did we know... District 13 was filmed with no computer animations at all.
      • The civilization that was living in that planet is traveling to a little blue planet that was nearby at a modest 100 light years. Invasion is scheduled for next Tuesday. Little did we know... District 13 was filmed with no computer animations at all.

        Can I borrow the machine they used to travel in time then?

        • Re: (Score:3, Funny)

          by Anonymous Coward

          There's no need for time travel. An FTL drive (time machine) would have allowed them to arrive before the impact was visible here, a "few thousand years ago." Which, thanks to relativity, would mean they'd arrive before it happened.
            Arriving next tuesday means they've got a drive on their generation ship that can hit a little over .1c or so - crossing about one light year every ten years. Impressive, but not a time machine.

          • Re: (Score:3, Insightful)

            by nextekcarl (1402899)

            FTL would only make them think the trip was shorter, not make them go back in time.

            • Relativistic speed (

              FTL speed (> 1.0c) makes them go back in time.

              • that was supposed to be: "Relativistic speed (< 1.0c) makes them think the trip was shorter, not go back in time."

                I used an actual less-than, so it thought it was an html tab

          • Re: (Score:3, Informative)

            by thasmudyan (460603)

            Having an FTL drive doesn't mean it's a time machine. The actual method of travel is important here. It's impractical to go at relativistic speeds that are a considerable fraction of the speed of light, and it's pretty darn impossible to accelerate even beyond 99% of c. Theoretically, going faster than c could mean going back in time, but there is simply no way to accelerate normal matter in this fashion.

            It's very likely any FTL drive technology would have to employ other means, like bending spacetime so th

            • Yeah it kinda does. (Score:3, Informative)

              by Chris Burke (6130)

              Having an FTL drive doesn't mean it's a time machine. The actual method of travel is important here.

              Yes actually FTL does mean you have a time machine, and the method of travel doesn't really matter. It's not like a Back to the Future time where you can arbitrarily go backwards and forwards as far as you want, it's limited to past-only and by how far and fast you can actually travel and how fast your non-superluminal spaceships can travel. But from some observer's reference frame you will have traveled b

              • Re: (Score:3, Informative)

                by Chris Burke (6130)

                Oops, my second link to the page with nice graphs [theculture.org] was hidden in a period. The explanation on that page uses instantaneous communication as its example for clarity and simplicity, but all you really need to do is break out of the light cone and you can potentially break causality with time travel.

              • But from some observer's reference frame you will have traveled back in time and broken causality by arriving at your destination before you left, simply by moving faster than c relative to them.

                If that were true, quantum entanglement would break causality. Actually, what we perceive as causality is a symptom, not the cause. Hence it's an illegal assumption that time travel would _have_ to occur every time local effects shift (for lack of a better word) between two points in space faster than it would take

                • Absolutely does. (Score:3, Informative)

                  by Chris Burke (6130)

                  If that were true, quantum entanglement would break causality.

                  Not it wouldn't, because nothing is traveling faster than c in entanglement, not even information. In fact, it is exactly for the reason I'm describing that demonstrates why quantum entanglement can't be used to send information. Nor can any effect resulting from the entanglement being collapsed on the "other end" be distinguishable from it collapsing on your end. There is no possibility of breaking causality.

                  However macroscopic-you traveling

                  • by khayman80 (824400)

                    Causality-wise, going faster than c by any method is impossible.

                    I've already responded to the parent agreeing with most of your position. However, I think this statement goes a little far. FTL travel almost certainly implies time travel, but relativity only makes a preferred frame seemingly unnecessary given current observations. It doesn't rule out a preferred frame altogether.

                    Also, violating causality is a good reason to be suspicious of a phenomenon, but I don't think it deserves the "impossible" label.

                    • Re: (Score:3, Informative)

                      by Chris Burke (6130)

                      However, I think this statement goes a little far. FTL travel almost certainly implies time travel, but relativity only makes a preferred frame seemingly unnecessary given current observations. It doesn't rule out a preferred frame altogether.

                      Relativity is predicated on the assumption that there is no preferred reference frame. It is because of that assumption that many of the laws of Relativity are required to ensure that it is the case. If there was a preferred reference frame such that the laws of phys

                    • by khayman80 (824400)

                      If there was a preferred reference frame such that the laws of physics only had to apply to it, but causality could be broken elsewhere, then the Theory of Relativity would be very different.

                      Yes, but like Newtonian mechanics, modern relativity would still be a useful first order approximation. Plus, to the best of my knowledge relativity has only rarely been tested to more than first order effects.

                      I'm also going to wait until we have some reason to actually prefer the many world interpretation over others b

                    • by Chris Burke (6130)

                      Yes, but like Newtonian mechanics, modern relativity would still be a useful first order approximation. Plus, to the best of my knowledge relativity has only rarely been tested to more than first order effects.

                      Well what I mean is that the Theory of Relativity only looks anything like it does due to the absence of a preferred reference frame. Newton's Laws are only a good approximation because its basic assumption that time is constant is approximately true for normal speeds/masses. It's difficult to see h

                • by khayman80 (824400)

                  But _if_ it works, it's not a time machine simply because it teleports matter between two points "faster" than it would take a ray of light to do so.

                  No, he's actually right [dumbscientist.com]- any FTL drive combined with a mundane conventional drive can be used to travel back in time.

                  If that were true, quantum entanglement would break causality.

                  Entanglement [dumbscientist.com] isn't a causal phenomenon.

      • by mcatrage (1274730)
        District 9 maybe. Unless these are aliens who do parkour which would be cool.
    • by Shakrai (717556) on Monday August 10, 2009 @08:31PM (#29018559) Journal

      The civilization that was living in that planet is traveling to a little blue planet that was nearby at a modest 100 light years. Invasion is scheduled for next Tuesday.

      Thankfully the invasion was called off when the aliens learned of mankind's secret weapons: lawyers, building permits and environmental impact statements. Said Fleetlord Atvar, "We came here looking to save our race, not to spend the next two hundred years filling out paperwork. We'll find a new home somewhere else, thank you very much."

      • Re: (Score:1, Funny)

        by Anonymous Coward

        The civilization that was living in that planet is traveling to a little blue planet that was nearby at a modest 100 light years. Invasion is scheduled for next Tuesday.

        Thankfully the invasion was called off when the aliens learned of mankind's secret weapons: lawyers, building permits and environmental impact statements. Said Fleetlord Atvar, "We came here looking to save our race, not to spend the next two hundred years filling out paperwork. We'll find a new home somewhere else, thank you very much."

        Best misquote of a Harry Turtledove novel I ever read (it was my first)

        http://en.wikipedia.org/wiki/index.html?curid=5740554 [slashdot.org]

      • The hell of it is, we could have really used the tax revenue they would have brought in.
    • by gijoel (628142) on Monday August 10, 2009 @08:44PM (#29018643)
      Not the civilization per se. Just the infant son of the leading scientist who tried to warn them of the impact.

      My calculation predict that he'll land somewhere in Kansas.
    • by StickANeedleInMyEye (1253490) on Monday August 10, 2009 @09:18PM (#29018833)

      The civilization that was living in that planet is traveling to a little blue planet that was nearby at a modest 100 light years. Invasion is scheduled for next Tuesday.

      Actually they landed here ~4 million years ago but accidentally killed the dinosaurs while landing their pyramids.

    • by Alarindris (1253418) on Monday August 10, 2009 @09:43PM (#29019011)

      Invasion is scheduled for next Tuesday.

      Must be waiting for Microsoft to releasing a patch for their retrocatalytic ion phaser driver.

    • by rrohbeck (944847)

      I loved the comment about Kryptonite and how the author of the original paper asked if anyone has a Kryptonite infrared spectrum so he can check :)

  • Actually... (Score:3, Funny)

    by RuBLed (995686) on Monday August 10, 2009 @08:08PM (#29018439)
    That's no moon.
    • by badzilla (50355)

      I can't believe I had to scroll so far down looking for this!

      • by EdIII (1114411) *

        I can't believe I had to scroll so far down looking for this!

        No kidding. I almost lost faith in the geeks here at Slashdot... .phew.

  • Why have we never seen any sci fi dooms day weapons of the quality?
    • Re: (Score:3, Informative)

      by Brian Gordon (987471)

      There are probably more efficient ways of wiping out life than pouring on the order of 10^30 joules into accelerating a gigantic impactor.

      • by Evil_Ether (1200695) on Monday August 10, 2009 @08:52PM (#29018681)
        More efficient ways yes, but more satisfying?
      • There are probably more efficient ways of wiping out life than pouring on the order of 10^30 joules into accelerating a gigantic impactor.

        Put the same energy into lots of small relativistic impactors. Craft the trajectory so that the acceleration phase is masked by nearby stars. Distribute the impactors so that all orbital installations and both sides of all inhabited bodies are blanketed with enough energy to raise the temperature to 500 degrees celsius for all biomes. Time them, so that they all arrive at the same time. The victims will have only minutes of advance warning, if any at all. (Idea from _The Killing Star_)

        • What's the point if it still uses the same energy? Anyway a single small relativistic impactor would probably inflict massive damage. You don't need to strip the crust off a world to render it uninhabitable.

    • There is a place. It is a place where broken rocks ring a red sun.
      Several centuries ago, we discovered a race of arthropod-like creatures called Whilles, with whom we could not deal.
      They rejected friendly overtures on the parts of every known intelligent race. Also, they slew our emissaries and sent their remains back to us, missing a few pieces here and there.
      When first we contacted them, they possessed vehicles for travel within their own solar system. Shortly thereafter, they developed interstellar travel.
      Wherever they went, they killed and they stole and then beat it back home.
      Perhaps they didn't realize the size of the interstellar community at that time, or perhaps they didn't care.
      They guessed right if they thought it would take an awfully long time to reach an accord when it came to declaring war on them.
      There is actually very little precedent for interstellar war. The Pei'ans are about the only ones who remember any..
      So the attacks failed, what remained of our forces were withdrawn, and we began to bombard the planet.
      The Whilles were, however, further along technologically than we'd initially thought. They had a near-perfect defense system against missiles.
      So we withdrew and tried to contain them. They didn't stop their raids, though.
      Then the Names were contacted, and three worldscapers, Sang-ring of Greldei, Karth'ting of Mordei and I, were chosen by lot to use our abilities in reverse.
      Later, within the system of the Whilles, beyond the orbit of their home world, a belt of asteroids began to collapse upon itself, forming a planetoid.
      Rock by rock, it grew, and slowly it altered its course. We sat, with our machinery, beyond the orbit of the farthest planet, directing the new world's growth and its slow spiral inward.
      When the Whilles realized what was happening, they tried to destroy it.
      But it was too late. They never asked for mercy, and none of them tried to flee. They waited, and the day came.
      The orbits of the two worlds intersected, and now it is a place where broken rocks ring a red sun. I stayed drunk for a week after that.

      http://www.amazon.com/Isle-Dead-Eye-Roger-Zelazny/dp/0743434684/ [amazon.com]

    • Doomsday Devices come in all shapes and sizes. Like this paper mache cone [slashdot.org].
    • Please turn in your geek card until you've read E. E. Smith's "Lensman" series.

      Then you will know about "sunbeams" and "dirigible planets", and can stop asking foolish questions like the above.

  • by Brian Gordon (987471) on Monday August 10, 2009 @09:03PM (#29018735)

    Giant impacts are thought to have stripped Mercury of its outer crust, tipped Uranus on its side and spun Venus backward, to name a few examples

    Is it just me or is that coolest thing ever? Forget massive trains [imageshack.us].. the male mind cannot help but drool at the idea of planets colliding.

    Venus is awesome; I can't even imagine what that would look like. The impactor rapidly accelerating the rock around it while the rock on the other side of the planet crumples and deforms under titanic pressure. Maybe the crust would be rigid enough to accelerate rapidly in big chunks while the big oceans of rock in the mantle churn and slowly come up to speed.. or maybe it would just blast most of the mass spaceward, leaving the planet to be pelted by continent-sized rocks for the next thousand years..

    But undoubtedly Uranus is the coolest collision. Gas giants are already terrifying (imagine falling straight down into the north pole of Jupiter, falling straight into the bullseye of roaring winds and bottomless stormclouds).. but a mass large enough to alter its inclination exploding through the upper atmosphere as a fireball, and slowly ablating as it buries itself deeper into progressively denser gases, and plunging deeper and deeper into the unplumbed depths of unimaginably violent, raging, endless storms, and finally sinking to the crushing depths of the great core furnace.. come on Hollywood, put your obscene special effects budget to use doing something like this.

  • That animation reminds me of a job interview I had once...
  • by NF6X (725054) on Tuesday August 11, 2009 @12:27AM (#29019871) Homepage

    TFA wrote:

    And there's another thing that I find personally very cool. Remember, HD 172555 is only 100 light years away. That is extremely close on a galactic scale (our galaxy is 100,000 light years across, so this star is our next door neighbor). It seems incredibly unlikely that this is a rare event in the galaxy, since this happened so close by and so recently.

    That's like saying "somebody living within five miles of me was struck by lightning last week, so it seems incredibly unlikely that being struck by lightning is a rare event on this planet". A single sample says nothing about the probability of the event, other than that it's nonzero.

  • How many stars in a sphere of 100 light years radius from the Sun?
  • ...as if millions of voices suddenly cried out in terror and were suddenly silenced

"Probably the best operating system in the world is the [operating system] made for the PDP-11 by Bell Laboratories." - Ted Nelson, October 1977

Working...