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Space Science

Deflecting Asteroids with Paint 51

Posted by timothy from the really-big-sprayer dept.
schnippy writes: "Researchers at the University of Arizona have calculated that small earth-crossing asteroids can be deflected by "coating them with a layer of white paint or dust." This finding won't be of much help against the larger doomsday asteroids (like the recently discovered 1950 DA) but it will help deflate military proposals to use nuclear weapons to deflect potentially hazardous asteroids."
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Deflecting Asteroids with Paint More

Deflecting Asteroids with Paint

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  • That's the ticket (Score:1, Informative)

    by Anonymous Coward
    Coat them in a reflective paint so that they don't heat up when entering the atmosphere...

    That'll work...
    • (* Coat [asteroid] in a reflective paint so that [it won't] heat up when entering the atmosphere... *)

      I bet you're in management.

    • Sounds like a meaningful job for advertising execs and graffiti artists alike. Imagine if you will...

      NEWSFLASH!...GIANT ASTEROID WILL HIT EARTH!!!...

      later:

      ...BRANDX COLA SAVES DAY BY USING BRIGHTLY COLORED LOGO TO DEFLECT ASTEROID FROM IMPACT WITH EARTH...

      even later:

      ...GRAFFITI TERRORIST HAS DEFACED BRANDX LOGO WITH DARK SKULL AND CROSSBONES, THUS NULLIFYING PREVIOUS RESCUE ATTEMPT...

      woosh!!!

  • What a poor writeup (Score:1, Insightful)

    by Anonymous Coward
    Most articles on the 1950 DA asteroid [astronomy.com] mention that it can be deflected "by selectively dropping white chalk or black carbon powder to darken or lighten some regions". That's because the potential impact is in 878 years, so a small nudge now can make a huge change over many centuries. In other words: yes this paint technique can help against 1950 DA. Claiming anything else shows a poor understanding of the basics of asteroid deflection.
    • hmm.. actually i think the astronomy.com article is the one with the poor writeup

      In the Spacedaily article [spacedaily.com] which actually quotes from the Science article, the study's principal author argues that his calculations apply to smaller asteroids that are within a decade of colliding with the earth:

      "Spitale said the proposed technique would be useless for a large asteroid or an asteroid less than decades away from Earth.
      'This technique will work best on objects the size of Golevka or smaller (300 meters, about 1,000 feet, or smaller). An object that size could do damage to the better part of a country. Even a 100-meter or 50-meter object can take out a good part of a city.'

      Doesn't sound like thats at all useful against 1950 DA to me..

  • Chaos Intervenes (Score:2, Insightful)

    by Perdo ( 151843 )
    If predicting the trajectory of an asteroid's orbit is so heavily dependent on surface reflectivity, how do we know the change we make will not bring it closer to earth and not farther away? I liken it to our ability to change the weather, but not predict the weather.

    I would prefer to make the trajectory change closer to the impact event so that we could more accurately predict the results.

    • Re: Rate of change (Score:3, Interesting)

      by Raetsel ( 34442 )

      Interesting choice...
      1. A small rate of change over a very long time

        (OR)

      2. A rapid change close to the point when change is needed
      We see these types of things happen all the time -- notably on 'real life' cop shows. Either you steer early and avoid an obstacle, or you yank the wheel at the last second, lose traction, and skid into oblivion anyway.

      I'll take the first choice, thanks. That way we can know earlier whether it's working or not, and take extra steps if necessary.

      • Re: Rate of change (Score:3, Interesting)

        by Perdo ( 151843 )
        I fully agree, but since an asteroid's orbit cannot be accurately predicted to "earth hit or miss" accuracy greater than about 20 years in advance, that little nudge may be the nudge that causes the asteroid to hit instead of miss. Strapping one of these magnetic bubble solar sails [nasa.gov] would alter an asteroid's orbit so drasticly, even on late notice, and be steerable to boot, that they make painting the surface white pale by comparison (pardon the pun).

        Same theory, more active approach and to paint it would still require a launch, intercept, and application of device, be it paint or a giant magnetic field. The best part is a system like this could be used to steer an earth crosser into earth orbit, providing plenty of zero G raw materials for future missions.


          • "...zero G raw materials for future missions."
          Or... a counterweight for a space [slashdot.org] elevator [slashdot.org]!

          I suppose the longer we wait, the more stuff we can take -- it'll take less fuel to get there. (Unless we're using antimatter propulsion in 850 years or so... then I guess it really wouldn't matter.)

          • God, I like how you think, even if we are on different sides of the T(H)GSB fence.

            What he is talking about folks, is the bigger the counterweight, The bigger payload your space elevator could carry, without needing a thicker teather toward the top. Also it enables construction by lowering strings from orbit, because there is something nice sized in orbit to teather to. This is especially important for the first strand, that will be too weak initially to support any weight at all, and certainly not the weight of an entire other strand.

    • If predicting the trajectory of an asteroid's orbit is so heavily dependent on surface reflectivity, how do we know the change we make will not bring it closer to earth and not farther away?

      a) PREDICTION is absolutely not dependend from surface reflectivity. The reflectivity is know, as well as the orbit is known.

      You likely mean: the orbit itself is so heavyly dependednd on reflection ....

      b) a change in reflectivity can only give an extra push on the orbiting object directing outside of the solar system.

      Hence the orbit gets wider, the object will be farer from the sun.

      The problem you are refering to: "how to prevent that an orbit change actually complicates the messs" only is a problem for asteroids which have a part of their orbit closer to sun than earth. As those need to "accelerated outwards" in a way that they do not cut the earth orbit at the point where the earth is.

      For asteroids which are allready outside but could come closer or just touch the earth orbit, any acceleration is ok.


      I would prefer to make the trajectory change closer to the impact event so that we could more accurately predict the results.

      Well, acceleration by sun light is far more predictable than a rapid acceleration with "a so far not existing technology":
      1) the mass of the object is know
      2) the sice of the surface is known
      3) the orbit(distance) is known
      4) the intensity of sunlight is known

      What could we do to accelerate an asteroid close to the impact point? Hitting it with a(some) nuke(s). I asume is the only thing we can do.

      Landing and placing a power plant and installing ion engines ... thats clost to makeable but still SF.

      All other engines are not suiteable (chemical rockets) or equal complicated (plasma engines) to install on the surface.

      Why won't a nuke likely not work?

      A: the impact of a nuke on the asteroid might simply wreck the nuke and not ignition it.
      B: the asteroid might break apart and not realy change trajectory of the parts
      C: you definitly would need several nukes, all nukes hitting after the first one need to adjust their OWN trajectory to hit the asteroid which is allready changing its orbit (increasing risk of B)

      Oh: ignition of a nuke nearby or in front of the asteroid (avoiding A:) only might melt its surface, but not evapor enough material to change its course.

      Regards,
      angel'o'sphere

      • Re:Chaos Intervenes (Score:3, Informative)

        by Perdo ( 151843 )
        1) the mass of the object is know

        The mass of an asteroid is not known. 433 Eros, which we know better than any other asteroid, still has an unknown mass for purposes of calculating it's orbit 800 years into the future. Being off by even a few grams results in being off by thousands of miles in final trajectory. It's apparent mass is between 6.69 and 7.2 x 10^15 kg enough to put our calculations off by entire solar units, after 800 years have passed. There is also the problem of asteroids constantly shedding and gaining mass due to collisions, dust deposition and even the solar wind itself depositing dust or blowing deposited dust away.

        2) the sice of the surface is known

        "Sice" is an Ceske (Check) word that I assume means reflectivity. Consider this: look at a common crystal. Notice that it's reflectivity is determined by it's orientation to the veiwer. The moon always presents the same face to earth, but the sun "gets to see" all sides of the moon. If we base our calculations of an objects reflectivity on observations from earth, or a spacecraft orbiting the asteroid, we cannot make accurate calculations of the objects reflectivity because only one set of data really matters, the reflectivity of the object from the sun's point of view, which may also be variable.

        3) the orbit(distance) is known

        The orbit can be guessed. We can know with relative certainty where an object was. We can know fairly accurately where it will be in 20 years. We can wildly speculate where it will be in 800 years. Consider the cesium beam atomic clock. It is accurate to 1 x 10^-17 seconds. Such a clock would be off by as much as a thousandth of a second in 800 years. Given that deviation, Calculations of an orbit could be off by several kilometers just on un-guessable timing errors alone. Unfortunately, there is a mathematically unsolvable problem too: The Three-Body Problem, well explained here. [igs.net] Unfortunately, we are faced with a 32 body problem, just counting the sun, planets and major moons. It doesn't even end there. The mass of any body is not consistent across it's surface. For instance, there are places on the earth that "pull" harder than others. This is well mapped on earth, and there are satellite launches planned or in orbit to more closely map this phenomenon, but we have just barely scratched the surface as far as research into, for instance, Jupiter's Local gravitational variations, which have a much greater impact on solar orbit calculations than any body in the solar system.

        4) the intensity of sunlight is known

        The intensity of sunlight is unknown. The sunspot activity cycle causes the solar wind to change in intensity. Additionally, it warms and cools cyclically. I've heard on a ten thousand or so year cycle, but I cannot remember the source. The sun is also very gradually warming due to the natural life cycle of stars. The planet's magnetic field's slow and accelerate the solar wind and create airfoil shaped shadows in their wakes, through which asteroids must pass. The Planet's magnetic fields also have a quite variable affect on the solar wind, as watching an aurora will show you.

        I'll leave you with this:

        You can watch a wave sweep the beach and know that the beach will likely have the same shape after its passing but to predict with certainty where a particular grain of sand will go is not within our abilities and never can be.

        There are many waves, and even they affect the orbits of asteroids, as the friction of tides moved the moon out to it's current orbit, and slowed the earth to it's present length of day.

        Care to guess the coefficient of friction of metallic-hydrogen against it's unknown but assumed "rocky" core? Tidal forces within Jupiter will have to be factored in too.

        Just to many variables.
        • The mass of any body is not consistent across it's surface. For instance, there are places on the earth that "pull" harder than others. This is well mapped on earth, and there are satellite launches planned or in orbit to more closely map this phenomenon, but we have just barely scratched the surface as far as research into, for instance, Jupiter's Local gravitational variations, which have a much greater impact on solar orbit calculations than any body in the solar system.

          The earth's variable gravity field is caused by the uneven surface (presence of mountains and valleys) as well as concentrations of mass that are denser than average. While Jupiter may have a solid core, the vast majority of the planet is gaseuos or fluid. There can be no mountains or valleys, and any concentrations of mass that are denser than average would automatically sink and redistribute themselves.

          For these reasons, I think you'll find that Jupiter's gravity field is quite uniform.
          • There are persistent and non-persistent variations in jupiters atmosphere. The great red spot, for instance, is a 12,000 km by 25,000 km by 8 km "tall" variation from the "surface" of Jupiter. 2.4 billion cubic kilometers of gas which is denser than the surrounding gasses forced upward by heat. This is an example of a continuously variable local gravity anomaly. We know that the red spot's composition and shape changes constantly and we cannot predict it's future. A recent collision with with a smaller white spot also drasticly changed it's color to a much lighter shade.

            Jupiter also spins, so exibiting the same flattened sphere shape, and resulting reduced local gravity of the poles, that the earth has. To assume jupiter's metallic hydrogen core exibits no topographic variations is also unrealistic for purposes of calculating gravitational variations.

            Additionally, imagine and iron bodied asteroid orienting itself to Jubiter's amazingly large magnetic field like and iron fileing would to a common magnet. This would change the meteorite's angle of incedence to the solar wind making it more or less "aerodynamic". We could change a meteors resistance to the solar wind by modifying it's reflectivity only to have our work undone because a previously stable meteor would begin to tumble, drasticly altering it's coefficient of drag.

            Again, there are just too many variables.
  • Use radioactive radium paint

    It's both paint and nuclear! You could have paint ball games on a planetary scale.Use radioactive radium paint it's both paint and nuclear! You could have paint ball games on a planetary scale.Use radioactive radium paint it's both paint and nuclear! You could have paint ball games on a planetary scale.

  • Why does everyone whine about nuking asteroids? Why NOT nuke them? Even the really big ones? Even the ones that people say are "the size of Texas"? And I don't mean the "try one nuke and give up" that they do in the movies right before sending the poorly trained oil rig workers. I mean rain down thousands, if not tens or hundreds of thousands, of 150 megaton nukes. Turn that whole nasty blob of metal and rock into white hot hell-fire plasma. Not only would it be fun and pretty, but we'd also get to empty out all the really nasty big mother nukes that have been sitting around and collecting dust forever.
    • Besides, a nuke would make an excellent paint spreader, or were they planning on sending the three stoodges up to paint a 15km asteroid.

      Perhaps we could hit Saddam with a big paint grenade and he would have to take a knee and pretend he was dead when we hit him with a second shot.

      "Ok, we've painted you, you have to put all your weapons of mass destruction behind your back!"
    • Texas is 801 miles across.

      The moon is 1375 miles across.

      um... ok...

      Let's go ahead and nuke texas because all the nukes in the world aint gonna stop a a rock the size of it.
  • but it will help deflate military proposals to use nuclear weapons to deflect potentially hazardous asteroids.

    No it doesn't silly, it means we need to attach a bunch of paint buckets to a bunch of nuclear missles, fire the paint-missles at the big rock, and *boom* *splat*, earth is saved again!

  • Armaggeddon 2 (Score:2, Funny)

    by Anonymous Coward
    So in Armaggeddon 2, instead of oil rig workers, they'll send... house painters?
  • when it comes round the next time and it's *already* white!
  • Put huge type R stickers on them as that will make them faster in whatever direction is opposite from the sticker location. Or paint them yellow, yellow isa fast color.
  • At last, Microsoft has software that's good for something!

  • Use a Laser (Score:2, Interesting)

    by AeiwiMaster ( 20560 )
    Why not use a laser to heat
    the surface of the asteroid,
    This will create a hot plasma jet which
    will alter the trajectory of the asteroid.
    • Why not use a laser to heat
      the surface of the asteroid,
      This will create a hot plasma jet which
      will alter the trajectory of the asteroid.
      That would be perfect! I happen to know this laser trick very well. See, I've got this laser on my keychain and whenever I point it around in my house...my cat starts flipping all over the place.
      • (* That would be perfect! I happen to know this laser trick very well. See, I've got this laser on my keychain and whenever I point it around in my house...my cat starts flipping all over the place. *)

        Yes, but did you compare that reaction to that of *painting* the animal?

        If you are going to do science on cats, do it right. Otherwise, you waste a perfectly good pussy.

    • Re:Use a Laser (Score:2, Insightful)

      by Tablizer ( 95088 )
      (* Why not use a laser to heat the surface of the asteroid, his will create a hot plasma jet which
      will alter the trajectory of the asteroid. *)

      The energy/force exerted it not likely to be any more than the power going to the laser itself. (You know, laws of conservation of mass/energy, etc.) Our lasers currently are way too weak for such.

      We have a hard enough time using them to blow up missles, and those lasers can only peak for a few seconds before they melt.

  • deflecting 1950 DA (Score:2, Informative)

    by Klox ( 29985 )
    This finding won't be of much help against the larger doomsday asteroids (like the recently discovered 1950 DA)

    Oink.NET and timothy obviously didn't read the article [astronomy.com] referenced [slashdot.org] by Slashdot yesterday (talking about 1950 DA). It explicitly states:

    The good news is that the same effect might be harnessed someday to provide the gentlest of all methods of nudging this or any other asteroid aside if it does turn out to be on a collision course. Simply altering the surface albedo in places, for example by selectively dropping white chalk or black carbon powder to darken or lighten some regions, could be enough to do the trick. If so, it might be the first time in history that a whitewash was the real solution to a serious problem.

    Maybe he's a busy guy, but I still think timothy should read the articles before he posts them (he posted both of these articles).
  • I'll give you this here apple with'n bite taken out of it, if'n I can paint yer asteroid fer a spell...

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