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Soapbox:Time we stop acting like an asshat of a species before we go out like dinos

Discussion in 'Off-Topic' started by hobbsyoyo, Feb 15, 2013.

  1. AdamCrock

    AdamCrock Polish Pudding

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    If I would be Hobbs I would do it for him! I would've make it all possible and Give'em hell Hobbs ^^ I would've give my whole support to protecting our earth ! Hell's bells I would've give everything to protect Earth ! Hells Bells ! ;) I'd just love to be na astronaut! ^^
     
  2. Kaitzilla

    Kaitzilla Lord Croissant

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    Die Hard 7

    Terrorists have taken over the world's newest asteroid mining company.

    They've pushed a giant meteor onto a collision course with Earth and are demanding $100 billion to push it just a little further to avert catastophe.

    But they missed one man, touring on a Senior Citizen discount. And now he's stuck there on Christmas, really pissed off. :mwaha:
     
  3. AdamCrock

    AdamCrock Polish Pudding

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    Who cares > ? Is that is what would You were about to ask ? Me I don't care if it is me I am this senior citizen ! , What do I do You ask ? I would've launch every missile possible and than some more ! (if that helps)! Hell Physics applies goddamit ! Than I would've pushed away the threat and be named the Earth Emperor ! xD :lol::mischief::king: ;)
     
  4. RobAnybody

    RobAnybody Emperor

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    What you are all missing is that the Bugs have attacked us. Starship Troopers was prophetic. The bugs have hurled an asteroid at us. Would you like to know more?


    Link to video.

    "The meteor was shot out of orbit by bug plasma..."

    Rico is our only hope. And maybe Doogie Howser, or perhaps Denise Richards. Although I liked her better in Wild Things. I don't know where I'm going with this...
     
  5. Formaldehyde

    Formaldehyde Both Fair And Balanced

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    Fortunately, we have an atmosphere. Just look at what asteriods and meteorites have done to the moon.

     
  6. RobAnybody

    RobAnybody Emperor

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    You have done nothing to disprove my Starship Troopers theory. I find that quite telling. ;)
     
  7. AdamCrock

    AdamCrock Polish Pudding

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  8. tokala

    tokala Emperor

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    Tunguska scale explosions can definitively be detected by seismographs. The one yesterdays was big enough to trigger the infrasound network in place to look for nuclear explosions, and I've already seem one report claiming that it also triggered seismographs. But in principle correct.

    Any crater you can see on that image is large enough that the impactor that produced it wouldn't have been stopped by our atmosphere. Plate tectonics and erosion tend to make even really big ones disappear.
     
  9. Winner

    Winner Diverse in Unity

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    Well, yes and no. Earth's atmosphere protects against smaller meteoroids which would otherwise hit the ground at ridiculous speeds. But it also tends to better absorb the energy of the impact and redistribute it over the surface, which kind of sucks when that energy is sufficient to level a land area the size of Bohemia to the ground :lol:

    Against larger asteroids, the atmosphere is of not much help - the average dinosaur killer is 10 km in diameter, so its upper end still basically sticks out of the troposphere while its lower side hits the surface.

    ---

    We should REALLY hope that we won't get hit by a comet. They are usually much faster than NEOs (less time to do something about them, more destructive energy) and their orbits around the Sun make them difficult to intercept.

    ----
    ----

    To all:

    is there any impact simulator which would simulate the climatic effects of a large impact? Let's say, how long would the 'asteroid winter' last, what the global warming would be afterwards, how much would the ozone layer be depleted, how much of world's vegetation would be destroyed by the firestorm, etc. etc.?

    EDIT: Hm, here is an interesting summary.
     
  10. tokala

    tokala Emperor

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  11. Winner

    Winner Diverse in Unity

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    Quite a bit larger than previously estimated, and more serious.

    ---

    Here's the table I was looking for:

     
  12. classical_hero

    classical_hero In whom I trust

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    Actually we should be thankful for Saturn, since it has a large gravitational pull that most meteorites that enter the solar system are attracted towards it and thus most don't stand a chance of even getting close enough to earth.

     
  13. Winner

    Winner Diverse in Unity

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    Uhm, the role of the big gas giants (Jupiter's gravitational influence is far more important) is debatable. I'd say they neither protect nor harm the inner planets. Their role was more important early during the formation of the Solar System.
     
  14. Tee Kay

    Tee Kay Silly furry

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    Meteorites already exist in the solar system by the billions.
     
  15. NedimNapoleon

    NedimNapoleon Weird Little Human

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    What about Panspermia. What if meteorite is carrying a quantity of alien bacteria or microrganism. What do we do then?
     
  16. Cutlass

    Cutlass The Man Who Wasn't There.

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    That was a truly horrible scene. I don't recall it being that bad... :eek:
     
  17. Winner

    Winner Diverse in Unity

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    What if there are demons inside and if we crack it open and wash with human blood, they are released and unleash the Hell on Earth? :scared:

    AFAIK we've never found any living things in meteorites. The closest to that are the things in a meteorite which came originally from Mars, which may or may not be microfossils or very primitive bacteria-like organisms.
     
  18. uppi

    uppi Deity

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    Photomultipliers would be a bad choice for this sort of application. They have a lousy quantum efficiency (something like 20% at peak wavelength) and have a large detection area, so you get practically no spatial resolution at all. They're great (and I use them) for easy intensity measurements of small high-frequency signals, but no the right tool here.

    APDs have good quantum efficiency and fast response, but it is difficult to build an array from those and we don't actually need the fast response.

    The right tool for taking images of very weak signals would be an EMCCD camera. They take a megapixel of data, have a resolution in the micrometer range and a quantum efficiency of up to 90%. If you cool them down to about -100deg C they also have low noise. Compared to the other options they're slow, but we would want to integrate the signal anyway. They're quite expensive, though.

    But the initial point stands: No matter how good your efficiency of detecting photons is, you cannot detect more photons than those that are actually there. (In the mean, anyway. For a single shot, how many photons are there is actually not defined unless you have a Fock state)

    It would be interesting to calculate at what distance it would become physically possible to detect a 2m object with a reasonable telescope.
     
  19. tokala

    tokala Emperor

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    My guesstimate of about visual magnitude 20 as detection threshold seems to be correct if you look at the MPC bulletins.
    You need a wide field and a reasonably large aperture; the group in Spain that found 2012 DA14 is using three .45m f/2.8 scopes, the well-funded spacewatch project .9m f/3 and 1.8m f/2.7 instruments. For scanning purposes the 1.8m has about V=22 limiting magnitude, a half meter instrument about V=20.

    2012 DA14 peaked around V=7, at a distance of about 30.000 km. It has a diameter of about 50m. An asteroid with V=20 apparent magnitude would be about a factor 1.5e5 fainter. Assuming identical albedo and illumination angle, this corresponds to a distance of about 500.000 km for a 2m object, not much beyond the moons orbit.
    That close, it would move several degrees per day, so you would have to be really fast with follow-up observations or you lose it.
    And unless you get observation time at a large telescope, you will probably lose it anyway as the fraction of the orbit you can observe is too small for a good fix.

    For a body like the one coming down over Russia yesterday, if it was indeed about 15-17m diameter, the detection distance would be about 4 million km.
     
  20. uppi

    uppi Deity

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    V=20 should be around 2.5e-14 lux, which I estimate to be roughly 300 photons per seconds for a 0.5m telescope. So with a better detector one might improve the threshold by maybe an order of magnitude, but not much more. And that is, if it isn't limited by background noise anyway, which I suspect it is. The best QE of a detector doesn't help if it mainly detects background photons.


    At 20km/s relative speed that's respectively 7 hours and 2 days of advance warning. That might be just enough time to evacuate a big enough area.

    So the technology is there and unlikely to improve much, but there is always the possibility of a blindside hit by an object coming from the wrong direction. So what exactly are you suggesting we should do, hobbsyoyo?
     

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