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Paintball Pellets As a Tool To Deflect Asteroids

Posted by Soulskill on from the get-'em-good dept.

SternisheFan sends this quote from an article at MIT's Technology Review: "In the event that a giant asteroid is headed toward Earth, you’d better hope that it’s blindingly white. A pale asteroid would reflect sunlight — and over time, this bouncing of photons off its surface could create enough of a force to push the asteroid off its course. How might one encourage such a deflection? The answer, according to an MIT graduate student: with a volley or two of space-launched paintballs. Sung Wook Paek, a graduate student in MIT’s Department of Aeronautics and Astronautics, says if timed just right, pellets full of paint powder, launched in two rounds from a spacecraft at relatively close distance, would cover the front and back of an asteroid, more than doubling its reflectivity, or albedo. The initial force from the pellets would bump an asteroid off course; over time, the sun’s photons would deflect the asteroid even more."

153 comments

  1. Too tenuous by hessian · · Score: 4, Funny

    That's a long shot plan right there.

    I think sending Bruce Willis with a thermonuclear device and a boatload of family drama might work even better.

    --
    Futurist Traditionalism
    1. Re:Too tenuous by ThunderBird89 · · Score: 1

      It certainly would, for turning the equivalent of an FMJ round into a shotgun shell. My vote is for a big-ass chemical thruster, those still have the greatest specific impulse we can muster on short notice.

      --
      Hyperbole: I use it liberally!
    2. Re:Too tenuous by Anonymous Coward · · Score: 5, Funny

      Spaceballs ?

    3. Re:Too tenuous by Dr_Barnowl · · Score: 3, Informative

      Rockets have *terrible* specific impulse, around 450s for a complex bi-propellant liquid rocket, and 250s for the stable, reliable solid rockets.

      Ion engines have specific impulse up in the thousands to tens of thousands of seconds.

      Rockets have a lot more thrust per unit of engine mass, but getting enough propellent up there to give an asteroid sufficient delta-V would be all but impossible - for every big-ass rocket, you'd need a 10x bigger assed rocket to get it there in the first place.

    4. Re:Too tenuous by toastar · · Score: 1

      Chemical Thrusters don't have high specific impulses, They have high thrust. If you want a specific impulse engine you'd use an ion thruster or a even a nerva.
      The issue with any type of engine is first you have to arrest the asteroid's spin.

    5. Re:Too tenuous by PolygamousRanchKid+ · · Score: 1

      It would be better to give this to the Mythbusters crew. They seem to be particularly adept at blowing things up. The myth would be, "Humanity can be saved from an impending asteroid collision". It would suck if it gets busted.

      Or now that we can make Higgs' Bosons in CERN, can't we shoot Higgs' Bosons at the asteroid, or something? Or if we untangle Superstring Theory, can't we just shove the asteroid into another unseen dimension?

      Please be creative with your answers, Hollywood is monitoring this thread . . .

      --
      Schroedinger's Brexit: The UK is both in and out of the EU at the same time!
    6. Re:Too tenuous by Dekker3D · · Score: 4, Interesting

      You could avoid half the delta-V by not slowing down-... just have the rocket speed up to max speed and slam into the asteroid. Calculate the engine size and fuel amount to be okay for the range you need it at, then make a few rockets to stand ready for various ranges. Crumple zones would let all the impact go into pushing, rather than shattering the thing. Even use some kind of internal room full of tiny airbags if you must. One-way valves (with a tiny air-hole for letting them deflate on impact and not burst prematurely) on all of them, inflate them the usual way or use a small amount of rocket exhaust that you cool down somehow. Simple, really.

    7. Re:Too tenuous by paiute · · Score: 5, Insightful

      That's a long shot plan right there.

      I think sending Bruce Willis with a thermonuclear device and a boatload of family drama might work even better.

      Modded funny but is actually insightful. What would happen is that the chance of the giant asteroid actually hitting the earth will start out less than certain, so the large expense of sending a mission to deflect it far from earth using a gentle push would result in debate and delay. Then the odds of impact will increase, but the expense of the mission will still be high. We will piss and moan, and a loud minority of self-anointed space experts who begin to say that the rock is actually going to miss, that it is all a liberal/conservative/alien conspiracy, that there is really no asteroid, etc. will get a lot of press. Finally the thing will be visible from earth and the shit will hit the fan but by then it will be too late to use mild persuasion, and we will have to send up whoever passes for Bruce Willis with a crapload of nukes. We will blow it into chunks, maybe even into gravel whose kinetic energy strips away the atmosphere.

      --
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    8. Re:Too tenuous by ShanghaiBill · · Score: 2

      just have the rocket speed up to max speed and slam into the asteroid.

      But that "max speed" would not be very high. Rockets only make sense if you need a LOT of thrust in a very short period of time (say, to get off a planet's surface). But if we are going to deflect an asteroid we will need to do it when it is still months or years away from hitting the Earth. Which means you will have months or years (rather than minutes) to get up to speed. So an ion engine would make more sense. They provide little thrust, but they can keep it up for a very long time. For a given amount of fuel, they provide much more total delta-v.

    9. Re:Too tenuous by Dekker3D · · Score: 0

      That means I had the wrong timescales in mind. But yeah-... calculate projectile size, -type- and fuel amount for the range you need. It was implied, because at those ranges ion engines are more effective.

    10. Re:Too tenuous by TFAFalcon · · Score: 1

      You could also some sort of a mass driver, only firing it when it's pointing in an appropriate direction.

    11. Re:Too tenuous by Lt.Hawkins · · Score: 2

      Oh shit. There goes the planet... (surprisingly less off topic than one would suspect!)

      --
      -- My Sig is a P228.
    12. Re:Too tenuous by slick7 · · Score: 1

      That's a long shot plan right there.

      I think sending Bruce Willis with a thermonuclear device and a boatload of family drama might work even better.

      Paint ball, 357 magnum, rail gun, asteroid; see the ever increasing progression of feeble stupidity?

      --
      The mind conceives, the body achieves, the spirit manifests.
    13. Re:Too tenuous by Anonymous Coward · · Score: 1

      You could avoid half the delta-V by not slowing down-

      Not nearly that much. Getting off Earth and out of its gravity well is 70-80% of your delta-v to a near-Earth asteroid. You save only half of the remainder.

      Crumple zones would let all the impact go into pushing, rather than shattering the thing.

      Crumple zones work fine at car speeds of about 100 km/hr, but less well for a rocket moving at 10,000 km/hr or so. The required depth of the crumple zone goes as the square of the velocity, so you need a crumple zone 10,000 times deeper than the few-tens-of-cm of a car's in order to get a similarly gentle impact.

    14. Re:Too tenuous by SuricouRaven · · Score: 1

      If you're talking hollywood physycs... with enough warning, could we just build an epic-huge rocket on earth and alter the planet's orbit enough for the asteroid to miss.

    15. Re:Too tenuous by SuricouRaven · · Score: 1

      That's what would happen in America. Half the voters wouldn't want to send a nuke anyway, believing that God will protect mankind. While America is still debating, China will blow it up instead. They have a space program and nuclear weapons, and a semi-dictatorial government can get things done a lot faster in a crisis.

    16. Re:Too tenuous by PolygamousRanchKid+ · · Score: 1

      That one's actually been done already: http://en.wikipedia.org/wiki/Gorath

      The year is 1982, and the film opens with the launch of the JX-1 Hayabusa spaceship into outer space. The ship, originally sent to collect data on Saturn, has its course diverted to investigate the mysterious star Gorath, reported as being 6000 times the size of the Earth. It is feared that the star's path could come dangerously close to Earth. The JX-1 reaches locates Gorath and it's much smaller than earth but with 6000 times the gravity.

      The United Nations band together to discover a solution to the problem, and decide that their only solutions are to either destroy Gorath or move the planet out of the way. Back on Earth, the UN decides on the plan to move the Earth out of the way of Gorath, the South Pole Operation. The plan is to have atomic energy channeled through huge atomic furnaces 500 meters below the surface, then fed though enormous pipes called thrusters which will all fire in unison. But for this to work they will need an area 600 kilometers producing an atomic force equal to that of 6,600,000,000 megatons to move the Earth 400,000 kilometers way from Gorath.

      That sounds like a great plan doesn't it? But there's always a catch . . .

      The atomic engines are completed and fired up, moving the earth out of the way of Gorath. But the heat from the engines awakens and frees a giant monster walrus, called Maguma, that attacks the South Pole base.

      So, your idea was good enough for a movie. If you have any other ideas, please send them to Japan or Hollywood. The world needs to be saved with better science fiction than they have to offer.

      --
      Schroedinger's Brexit: The UK is both in and out of the EU at the same time!
    17. Re:Too tenuous by Anonymous Coward · · Score: 0

      You need Bruce Willis's team to get you there, but for painting, The Karate Kid is the obvious choice.

    18. Re:Too tenuous by TheLink · · Score: 1

      You really think those sociopaths controlling the USA won't take action for their own sakes? Their lifestyle would be severely degraded if a large enough asteroid hits the earth.

      Action has been taken without the voter consent plenty of times.

      --
    19. Re:Too tenuous by dinfinity · · Score: 1

      My vote is to shoot moon rock at it from said moon.

      As far as I can see, the only thing that is slightly hard to do, is getting enough energy on the moon (which would have to be produced or transported there).

      Of course, we would also have to build a catapult that is able to launch moon rock precisely enough.
      And a mining facility.
      Then again, we'd pretty much want to do comparable things anyway (for multiple reasons).

    20. Re:Too tenuous by RockDoctor · · Score: 1

      impulse we can muster on short notice.

      That last term is the important one. Is your "short term" a day, a week, a month, a year, a decade, or a century. Only the last couple of those are noticeably different from "instantaneous" in my working environment.

      --
      Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
    21. Re:Too tenuous by bradley2j · · Score: 1

      Once the majority accepts the fact that the asteroid will strike the Earth the deniers will claim that this will in fact boost the economy by creating jobs. But secretly they will be hoping the crisis will decimate developing nations and put the US back on top.

    22. Re:Too tenuous by RockDoctor · · Score: 1

      But if we are going to deflect an asteroid we will need to do it when it is still months or years away from hitting the Earth.

      If you leave it until the PHA (Potentially Hazardous Asteroid) is a few hours travel from Earth, then you're going to need large forces and you've got no time for a plan 'B'. If you get it wrong, millions or billions will die.

      Most PHAs are going to be in an orbit with approximately the same period as the Earth (they can have different phase, inclination, argument of perihelion and eccentricity though), which increases the probability of encountering Earth.

      So, all realistic schemes that I've seen for deflecting real PHAs (do you want to see a Tunguska event over your town? Barringer Crater #2 in Hollywood?) have a lower force being applied for a longer duration, normally starting one or more apparitions (look it up) of the PHA before the one that people are worried about. Then, if the first device doesn't work adequately, the version-2 is added in the next apparition, then version-3, incrementally adding to the understanding of real planetoid-moving (as opposed to the theory) and hopefully mitigating the risk in time.

      Oh, sorry, not Hollywood friendly. Can't do it that way in the real world.

      --
      Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
    23. Re:Too tenuous by RockDoctor · · Score: 1
      Workable for an idea. And with a little attention to detail, you could use it multiple times.

      The precision of aim would have to be high. For a 100m asteroid in the nearest 10'th of it's orbit ... I make it between 5 microradians and 100 nanoradians.

      What is the likelihood of particles that miss the target coming back on their orbit to impact Earth (or the gun) a year later?

      Hmmm.

      --
      Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
    24. Re:Too tenuous by BevanFindlay · · Score: 1

      Guidance thrusters on the projectiles? Wouldn't need to be much, just enough to fix minor course errors. Simple enough tech, I would have thought (as long as it can survive the initial launch).

    25. Re:Too tenuous by sjames · · Score: 1

      I would suggest many smaller projectiles. It matters less if one misses that way and if it comes back around, it can burn up with little damage.

  2. science. by Anonymous Coward · · Score: 0

    Not as uncool as you thought!

  3. How accurate is his simulation? by Anonymous Coward · · Score: 0

    first or second order accurate.
    Either way I don't feel safe!

    1. Re:How accurate is his simulation? by jamesh · · Score: 1

      first or second order accurate.
      Either way I don't feel safe!

      If they declare that an asteroid is "headed towards earth" without taking into account the effect of photons in the first place, i'd have to wonder a little. What if they decide that an asteroid is not headed towards earth, but it happens to be "blindingly white" and the photons change its course so it is headed towards earth.

    2. Re:How accurate is his simulation? by iamhassi · · Score: 1

      first or second order accurate.

      According to the article we're already too late:
      "According to astronomical observations, this 27-gigaton rock may come close to Earth in 2029....From his calculations, Paek estimates that it would take up to 20 years for the cumulative effect of solar radiation pressure to successfully pull the asteroid off its Earthbound trajectory. "

      2029 - 20 = 2009, so we're too late.

      I still don't understand why the sun's photons are better at shoving a asteroid off-course than a rocket, but i guess if Star Trek used photon torpedoes they must be pretty good

      Aliens would sure think we're strange: "Why.... WTF.... did they PAINT that asteroid?!?"

      --
      my karma will be here long after I'm gone
    3. Re:How accurate is his simulation? by RightwingNutjob · · Score: 1

      The bigger questions are: how blindly white is it already and how massive is it. You need a very good handle on both numbers if you're trying to 1) get a tight estimate on its trajectory and 2) try to perturb it with radiation pressure. Either way, you need to visit the asteroid with a probe to get those numbers before you know if painting it white (or black) will give you enough delta v over the timescale you need.

  4. Why worry by slashping · · Score: 0

    The chance of getting killed by a car when crossing the road is orders of magnitude larger than the chance of getting killed by an asteroid.

    1. Re:Why worry by MightyYar · · Score: 3, Insightful

      That's true, but there's something more unnerving about losing the entire human race.

      --
      W..w..W - Willy Waterloo washes Warren Wiggins who is washing Waldo Woo.
    2. Re:Why worry by Anonymous Coward · · Score: 0

      As soon as an asteroid wipes out the human population, those odds are gonna shift a bit.

    3. Re:Why worry by fuzzyfuzzyfungus · · Score: 1

      As soon as an asteroid wipes out the human population, those odds are gonna shift a bit.

      True, the odds of anybody getting killed in a car accident will be substantially lower than they are now after an apocalyptic asteroid strike...

    4. Re:Why worry by slashping · · Score: 3, Interesting

      It would take a huge asteroid to wipe out the entire human race. We're talking once every 100 million years, or so. Before we spend any resources on detecting and deflecting asteroids, let's wait another 1000 years. On the scale of large asteroid impacts, a 1000 year delay is insignificant, but on the scale of human civilization, 1000 years is huge. If our civilization is much more advanced in 1000 years, we don't need our dated asteroid impact plans. If civilization crashes, our plans will be useless anyway.

    5. Re:Why worry by fox171171 · · Score: 1

      The chance of getting killed by a car when crossing the road is orders of magnitude larger than the chance of getting killed by an asteroid.

      The odds of winning big in the lottery aren't very high either, but guess what? It happens to someone on a fairly regular basis.

      As for an asteroid striking the Earth... maybe not likely in the short term (where it is almost infinitely unlikely), but in the long term the likelihood becomes very high (long enough term and it becomes infinitely probable).

      And maybe, just maybe, you'll win the lottery and be struck by a car while the driver is looking up at an incoming asteroid.

    6. Re:Why worry by GrumpySteen · · Score: 1

      On noes! Someone is doing something that I don't think is worthwhile! Make them stop!

    7. Re:Why worry by Alwin+Henseler · · Score: 1

      Depends on where you're walking; if you walk right in front of an asteroid, your chances of getting killed by it go up quickly.

    8. Re:Why worry by slashping · · Score: 1

      Hey, they can fantasize all they want, but I get to vote whether I want to have my tax money diverted to crazy projects.

    9. Re:Why worry by slashping · · Score: 1

      In the long term, we're all dead anyway. And I don't play in the lottery either. It's just as silly as worrying about asteroids hitting me.

    10. Re:Why worry by Anonymous Coward · · Score: 0

      That's true, but there's something more unnerving about losing the entire human race.

      I knew it wouldn't take long for someone to bring up "race" into the discussion.

    11. Re:Why worry by tnk1 · · Score: 4, Insightful

      Your point is valid, except that the problem with estimates like that is while they are useful for estimating the risk, they don't say much about whether an asteroid of the required size is actually on its way. In other words, we don't get a do-over if the rock shows up earlier than we thought it would. Not to mention that rocks of the necessary size could be generated by the effects of a collision with another body which then suddenly expels a rock on a collision course with Earth. In that situation, we may well not see it coming until just before the window in which we need to take action to deflect it.

      Existential threats like asteroid impacts are situations that you start planning to deal with as soon as you have the knowledge to do so. There is really no reason not to, since given the extreme consequences, it doesn't seem particularly absurd to maintain those plans in a constant state of revision. We know that an asteroid of sufficient size is going to hit again. It's only a matter of time. Maybe that time is a million years from now, maybe it's a week from now. I grant that we shouldn't be building an expensive specialized asteroid defense grid or mineshaft shelter/habitats right now, but an actual plan that could be feasible in the event that we end up with an unforeseen visitor is the right thing to do. In this case, scientists realize that it is very easy to miss Earth if you poke at the asteroid just a little bit when it is far enough out. It's a reasonable plan that really should not require that much expenditure to make happen, if required.

    12. Re:Why worry by tnk1 · · Score: 1

      We could all end up in a future like The Road Warrior. Looked to me like everybody in that post-apocalyptic situation died in some sort of car-related accident.

    13. Re:Why worry by slashping · · Score: 1

      I agree it won't hurt for people to spend some time brainstorming about this in their spare time. But before we actually set up a budget to look into this on a more structured scale, it would probably be better to use the same budget to improve road safety, for example, or encourage people to stop smoking.

    14. Re:Why worry by davester666 · · Score: 1

      We've got more than enough already. It's ok for the herd to be thinned a bit through stupidity and/or poor choices so we can spend a bit more on reducing the chances that everybody is lost.

      --
      Sleep your way to a whiter smile...date a dentist!
    15. Re:Why worry by Opportunist · · Score: 1

      Why? You say that as if it's something bad?

      --
      We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
    16. Re:Why worry by Opportunist · · Score: 4, Insightful

      Problem is, the herd thinning would not be done by brains power but by purchasing power. Now imagine an Earth where only managers and bankers will survive. The living will envy the dead.

      --
      We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
    17. Re:Why worry by Opportunist · · Score: 1

      Not really, you only get to decide which crazy project your tax money will be wasted on.

      --
      We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
    18. Re:Why worry by MisterSquid · · Score: 1

      In the long term, we're all dead anyway.

      Rationalizing action or inaction with the fact that everyone and everything will one day be dead always fails to convince. The fact of our mortality and the eventual end of everything we know is obvious to anyone who is alive to contemplate reality.

      The more interesting course of behavior is to strive even in the face of such facts, precisely as so many of us do.

      --
      blog
    19. Re:Why worry by Anonymous Coward · · Score: 0

      Five-hundred meteorites hit Earth each year. Megaton-sized Tunguska-style meteor airbursts happen every 300 years, but kiloton versions (i.e. as powerful as the nuke dropped on Hiroshima) happen about every year (usually over the ocean). One km meteorites hit every half-million years, ten kilometer meteorites hit every ten million years, and every 27 million years there's a mass extinction.

      Thus, it wouldn't be surprising if thousands or millions of people were killed by an impact event during our lifetime. That's dwarfed by the number of vehicle fatalities, but it's still high enough to make it an important concern.

    20. Re:Why worry by symbolset · · Score: 1

      Our ability to gauge these isn't perfect, but Extinction asteroids do come about every 100 million years, and the next one is either due now or late. The distribution isn't random. It's cyclic.

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      Help stamp out iliturcy.
    21. Re:Why worry by symbolset · · Score: 1

      To me a 27 million year periodic cataclysm is suggestive of an extra solar interaction with the galactic plane. The Solar system's orbit of the galactic center is slightly tilted off the galactic plane. With an orbital period of ~50my we pass through that plane about every 25my. The vast majority of our galaxy's mass orbits in a paper thin region on this plane, but not us. Milky way is a barred spiral, so sometimes we cross this dangerous region in a matter-rich bar like we are in now, and sometimes in a gap between which is less dense. It would seem that almost every time Sol passes through this plane in a bar, Earth experiences an extinction event. I would like to see more modelling of this.

      --
      Help stamp out iliturcy.
    22. Re:Why worry by Sentrion · · Score: 1

      I think davester was implying that we should as a society tackle the threats that pose a risk to all of us rather than convince people to stop smoking or drive safer, as implied by slashping. Your scenario of herd thinning by bankers and managers is actually more like what is happening now with our energy and environmental policies. Today's need for jobs and affordable energy trumps tomorrows need for jobs, affordable energy, or a safe planet that can actually sustain us. And in the end the bankers and managers, while possibly being able to horde more for the short term, won't have the physical skills, abilities, or resources of more sustainable groups such as the Amish or subsistence farmers in 3rd world countries, so they may eventually regret the decisions and folly of their youth.

      As for existential threats that could take out entire nations, I suggest we try to calculate where the asteroid will land before spending billions to deflect it. Taking "personal responsibility" is a popular concept these days, so maybe we should let the most affected nations pick up the tab to rescue them, unless there is a more long lasting benefit to helping them. For example, I might ask Germany to contribute a major share of the cost to rescue them from a potential collision. If the asteroid was going to wipe out North Korea, I might just not say anything and hope any remaining Inmin Gun allow outsiders to assist survivors. If Haiti was the target I would just move the asteroid without asking anything in return - the poor Haitians have always had it bad and always suffer through the worst earthquakes, hurricanes, and other disasters.

    23. Re:Why worry by merxete · · Score: 0

      The living will envy the dead.

      maybe in soviet russia

      I plan to enjoy life, even if there are fewer people. There's quite an untapped potential in the quality of life if technology is used FOR us in an optimized manner. I believe we'll figure it out before shit hits the fan. It needn't be that bad for the prepared. Yeah, it'll definitely suck for many people though :| o_o

    24. Re:Why worry by kerrbear · · Score: 1

      Now imagine an Earth where only managers and bankers and politicians will survive. The living will envy the dead.

      Fixed that for you.

    25. Re:Why worry by MightyYar · · Score: 1

      Alright, but asteroids large enough to kill everyone in a major metropolitan area come more frequently. Tunguska-sized events might be as frequent as once every 400 years. If we address this more immediate, more manageable risk with today's technology, maybe in 1000 years we will have slowly progressed far enough to address larger threats.

      --
      W..w..W - Willy Waterloo washes Warren Wiggins who is washing Waldo Woo.
    26. Re:Why worry by flyingsquid · · Score: 1

      We know that an asteroid of sufficient size is going to hit again. It's only a matter of time. Maybe that time is a million years from now, maybe it's a week from now.

      Asteroids are a lot like sharks. They're scary and exciting, they're good antagonists for movies, and so we tend to overestimate the danger they pose. Yes, a shark can tear your arm off, and if you happen to run into one while swimming, you should probably head the other way. But the reality is that far more people are killed by dogs, bees, car accidents, choking on food, drug reactions, and soforth.

      In terms of natural disasters, the big killers are earthquakes, cyclones, tsunamis and floods. Wikipedia has a list: http://en.wikipedia.org/wiki/List_of_natural_disasters_by_death_toll

      . Since 1900, the most deadly natural disasters have included the 1931 China floods (150,000-4 million deaths), the 1971 earthquake in China (240,00-800,000 deaths), the 1970 cyclone in Bangladesh (500,000 deaths), and the 2004 tsunami (280,000 deaths). There are no well-documented instances of meteorites causing mass casualties, but even taking an ancient Chinese report of 10,000 deaths at face value, the worst impact event in the past 1000 years wouldn't even score as the worst natural disaster in the past two years.

      Or look at it in geological terms. The human species has been around for about 200,000 years. There is just a single well-documented case of an asteroid causing an extinction in the past 500 million years, the Cretaceous-Paleogene Chicxulub impact that wiped out the dinosaurs. The odds of such an event happening in the next ten thousand years or so are vanishingly remote. And other major extinctions coincide with ice ages (Eocene-Oligocene event, Ordivician-Silurian event) or volcanic eruptions (Permo-Triassic, Triassic-Jurassic, Cenomanian-Turonian events). So if we really want to worry about existential threats to the survival of the species, we should worry about ice ages and volcanoes, not asteroids.

    27. Re:Why worry by Anonymous Coward · · Score: 0

      As for existential threats that could take out entire nations, I suggest we try to calculate where the asteroid will land before spending billions to deflect it. Taking "personal responsibility" is a popular concept these days, so maybe we should let the most affected nations pick up the tab to rescue them, unless there is a more long lasting benefit to helping them. For example, I might ask Germany to contribute a major share of the cost to rescue them from a potential collision. If the asteroid was going to wipe out North Korea, I might just not say anything and hope any remaining Inmin Gun allow outsiders to assist survivors. If Haiti was the target I would just move the asteroid without asking anything in return - the poor Haitians have always had it bad and always suffer through the worst earthquakes, hurricanes, and other disasters.

      Dear Saudi Arabia,

      We noticed you like meteorite fragments. Here, have a spare one, just in case anything happens to the first.

    28. Re:Why worry by tnk1 · · Score: 1

      See, I think I need to sort of show where I am coming from. I don't fear things that simply kill people. Everyone is going to die sometime. I am more concerned about things that will end civilization and/or humanity.

      Asteroids may be movie friendly and rare, but they are actually easier with current technology to deal with than lots of other disasters. It may cost a billion dollars to put some paint on a rock, but if it does the job, that threat is dealt with.

      As for the problems you might consider a better use of money to spend for, you may well be not considering how intractable they actually are.

      If you get in a car accident, you could die. Still, even if you didn't ever end up dying in a car, you are going to die of a heart attack, or cancer, or food poisoning, or (eventually) by being hit by lightning on a clear day. Your chances of death start to become 100% as time goes on.

      People are always going to find ways to kill themselves or others and they will use their intelligence to counter your best efforts. Spending to stop that is like throwing money down a bottomless pit. Still, the only nice thing about that is that most people will find that their actions will eventually fall off as civilization starts being threatened.

      Eventually, they will act to stop their activities in that regard or the people will thin out enough that accidents or disease simply decrease due to a lower population density. In short, the problems you are talking about will generally self-mitigate.

      With a piece of mass being hurled at us by blind physics, there is no mitigation and the threat can be existential in a way that car accidents will never be, no matter how many people are killed by them every year. That's why it is a particular threat. Car accidents might kill billions over the years, but how do you count the number of people who will never even be born because one rock ended human civilization, and possibly even the species, all at once?

  5. Of course, if it doesn't work by Anonymous Coward · · Score: 0

    We can all die a colorful death

    1. Re:Of course, if it doesn't work by Anonymous Coward · · Score: 0

      We can all die a colorful death

      Not really. Its just white paint, seems kind of boring.

    2. Re:Of course, if it doesn't work by Anonymous Coward · · Score: 2, Funny

      Not really. Its just white paint, seems kind of boring.

      Steve Jobs just turned twice in his grave.

    3. Re:Of course, if it doesn't work by Anonymous Coward · · Score: 0

      It'll be white on one side, dark-coloured on the other, and it'll have rounded corners. Steve Jobs just started wanking again.

    4. Re:Of course, if it doesn't work by Opportunist · · Score: 1

      ...and sued the organization staging the project into oblivion, resulting in no money being left to save the human race. But you have to understand, he had to do it to protect the shareholder value.

      --
      We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
  6. Probability and magnitude are both relevant by perpenso · · Score: 5, Insightful

    The chance of getting killed by a car when crossing the road is orders of magnitude larger than the chance of getting killed by an asteroid.

    True. However one asteroid can kill all of us, unlike one car.

    The probability of an event must be combined with the magnitude of an event when assessing the risk.

    1. Re:Probability and magnitude are both relevant by slashping · · Score: 1

      But there's not just one car, there are about a billion cars, so even if you multiply the probability by the magnitude, the asteroid is still insignificant.

    2. Re:Probability and magnitude are both relevant by Anonymous Coward · · Score: 1

      I'm not sure you've thought this through. The likelihood of the Earth being hit by an impactor that's large enough to wipe out humanity is 1 in 1. It's going to happen. The likelihood of humanity being wiped out by all the cars on the planet is somewhat less than that.

    3. Re:Probability and magnitude are both relevant by slashping · · Score: 0

      The likelihood of the Earth being hit by an impactor that's large enough to wipe out humanity is 1 in 1

      No, because there's a good chance humanity will be gone before that big impactor hits the earth.

    4. Re:Probability and magnitude are both relevant by Rhywden · · Score: 1

      Ah, I see now. That's why some people are so dead-set against self-driving cars!

    5. Re:Probability and magnitude are both relevant by guises · · Score: 0

      Things that happen after I die aren't important. I don't know why people keep railing on about this "environment" nonsense either, somebody wasted my time with his "endangered species" prattle just this morning - I could eat nothing but Ethiopian wolf every day for the rest of my life. That's not a shortage.

      - Rush

    6. Re:Probability and magnitude are both relevant by Anonymous Coward · · Score: 0

      While you are at it, can you tell me the winning lottery numbers?

    7. Re:Probability and magnitude are both relevant by Anonymous Coward · · Score: 0

      Ah, I see now. That's why some people are so dead-set against self-driving cars!

      Perhaps we should require that all self-driving cars must carry a passenger. The survival of humanity is at stake after all.

    8. Re:Probability and magnitude are both relevant by jamesh · · Score: 1

      Things that happen after I die aren't important. I don't know why people keep railing on about this "environment" nonsense either, somebody wasted my time with his "endangered species" prattle just this morning - I could eat nothing but Ethiopian wolf every day for the rest of my life. That's not a shortage.

      Millions of years have ensured that the surviving genes are the ones that do things to ensure the survival of their offspring.

      You, sir, are an evolutionary dead end, so I guess the problem takes care of itself.

    9. Re:Probability and magnitude are both relevant by Anonymous Coward · · Score: 0

      While you are at it, can you tell me the winning lottery numbers?

      39, 69, 3, 34, 84, 25

      For some lottery, eventually, probably before the extinction level asteroid strike though.

    10. Re:Probability and magnitude are both relevant by Hentes · · Score: 1

      Assuming that you care about the survival of the human race. For people who don't, fear of asteroids is irrational.

    11. Re:Probability and magnitude are both relevant by Roachie · · Score: 1

      ya know its really too bad you posted as AC, I would have bumped this one up.

      --
      This sig is not paradoxical or ironic.
    12. Re:Probability and magnitude are both relevant by ThatsMyNick · · Score: 1

      Is you last name Limbaugh, by any chance?

    13. Re:Probability and magnitude are both relevant by RicktheBrick · · Score: 1

      The chances of getting killed by an asteroid are orders of magnitude larger than the chances of anyone in the world thanking us if we did manage to deflect one.

    14. Re:Probability and magnitude are both relevant by gmhowell · · Score: 1

      Things that happen after I die aren't important. I don't know why people keep railing on about this "environment" nonsense either, somebody wasted my time with his "endangered species" prattle just this morning - I could eat nothing but Ethiopian wolf every day for the rest of my life. That's not a shortage.

      Millions of years have ensured that the surviving genes are the ones that do things to ensure the survival of their offspring.

      You, sir, are an evolutionary dead end, so I guess the problem takes care of itself.

      Given his preference for young boys in the Dominican Republic, I'd say you hit the nail on the head.

      --
      Jesus was all right but his disciples were thick and ordinary. -John Lennon
    15. Re:Probability and magnitude are both relevant by Anonymous Coward · · Score: 0

      And? So what? Anyone with even a bit of intelligence can see how pointless it all is. It's just fun and instinctual, so it happens anyway.

    16. Re:Probability and magnitude are both relevant by Anonymous Coward · · Score: 0

      To put it another way: I would prefer to run a 50% chance of an accident that removes 1% of my body mass (which I can survive) than a 1% chance of an accident that removes 50% of my body mass (which would kill me). The first one is the regular death toll from cars; the second is the existential threat to humanity from asteroids.

    17. Re:Probability and magnitude are both relevant by Raenex · · Score: 1

      The likelihood of the Earth being hit by an impactor that's large enough to wipe out humanity is 1 in 1.

      Probability is not your strongsuit. Life on Earth has survived for billions of years. Humans are extremely resilient. There is no guarantee that an impactor large enough to wipe out humanity will hit Earth.

    18. Re:Probability and magnitude are both relevant by Anonymous Coward · · Score: 0

      Look everyone. It's slashdot's own trolling little waldo, gmhowell!

    19. Re:Probability and magnitude are both relevant by Anonymous Coward · · Score: 0

      However, in your next life, you will reap exactly what you sown in this lifetime. How poetic.

      Captcha: hogging

    20. Re:Probability and magnitude are both relevant by rubycodez · · Score: 1

      while technically correct I must point out those numbers won already. please provide next week's numbers

    21. Re:Probability and magnitude are both relevant by Anonymous Coward · · Score: 0

      Quit projecting about your odd penchant for young lads gmhowell. You give yourself away.

  7. why not a simple rocket by cats-paw · · Score: 1

    with enough advance warning would simply landing a rocket on the asteroid and having it provide a constant thrust be enough to have the asteroid miss ?

    at a great distance it would take very little course adjustment which could be provided by a very low thrust.

    the obvious complication being if it's tumbling. even then it seems that such a scheme would still work as the rocket could align itself under guidance or using the stars and provide force at the proper time.

    not sure why this is never mentioned as an option.

    --
    Absolute statements are never true
    1. Re:why not a simple rocket by Anonymous Coward · · Score: 0

      If you have enough time, and enough resources, there are lots of options. The more advanced version of this is steering the asteroid into orbit, then mining it.

    2. Re:why not a simple rocket by slashping · · Score: 1

      How much thrust would you be able to generate for long periods of time, and where does the energy come from ? Huge solar panels ?

    3. Re:why not a simple rocket by SJHillman · · Score: 1

      It's been mentioned quite often... probably why it's no longer considered news

    4. Re:why not a simple rocket by Anonymous Coward · · Score: 0

      That's the issue. On the other hand, dropping paint on the asteroid provides thrust as if powered by a solar panel the size of the painted area, so paintballs > simple rocket.

    5. Re:why not a simple rocket by Anonymous Coward · · Score: 1

      Not really. Photons carry a lot of energy, but hardly any momentum. It is much more efficient to use the energy collected from a solar array to power a thruster of some sort (which ejects reaction mass, i.e. propellant) to generate the momentum change, rather than relying on the miniscule momentum imparted upon the array directly.

    6. Re:why not a simple rocket by tnk1 · · Score: 1

      Painting the asteroid, assuming there was a good way of doing it, is probably more reasonable than building an engine to do it. The rocket engine would be more complicated and need to be lifted off Earth and make it to the asteroid in operable condition, whereas all you need to do with the paint is disperse enough of it to thinly cover the asteroid.

      There is also the possibility that if you believed that the underlying material of the asteroid was lighter or would outgas, you could set off explosions to disrupt the top layer of material on the object and expose the lighter colored material to the sun which would then start causing release of those materials in gaseous form. That would probably work best with a comet, since they are probably chock full of volatiles. The only issue is that if you did rely on outgassing from the comet, you'd have to make sure the new route was predictably away from Earth. Of course, given how hard it is to hit Earth in outer space, as long as you didn't win the lottery, almost any change in its velocity or bearing would make it miss.

    7. Re:why not a simple rocket by Anonymous Coward · · Score: 0

      extinction level asteroids are very large. Good fun to calculate the burns required to accomplish this, assuming it's detected 3 years out, and making decent estimates about the art of the possible for asteroid thrusters.

    8. Re:why not a simple rocket by Arker · · Score: 3, Insightful

      Actually 'landing' on it would be a huge problem. An asteroid is not typically one large smooth rock, after all. And it will definitely be 'tumbling' in relation to you as well. So it would be a very difficult docking maneuver on an uncertain surface. And remember these things arent large enough to generate enough gravity to notice either. So it's basically all in zero-g.

      Spraying a load of paint at it would be orders of magnitutude easier, and still wouldnt exactly be easy.

      --
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    9. Re:why not a simple rocket by gman003 · · Score: 2

      The problem is fuel. We don't have rockets that can fire for months. We have rockets that can fire for minutes. They provide a huge amount of thrust during that time, but you would need far, far more thrust than any existing rocket can provide to move an asteroid off-course.

      A vague possibility is an ion engine of some sort. These have much lower thrust, but can run much longer off the fuel they carry. The technology still isn't very proven, though - and trying to land an engine, intact, on an asteroid, it a tough proposition.

      The paint idea sounds more feasible. It's basically making it into a cheap, inefficient solar sail. It doesn't require tricky landings, it doesn't require a lot of fuel, you just aim some "paintballs" on a ballistic intercept path. The only downside is that, being inefficient, you have to catch it early. But if you've got a decade's warning or so, you should be good.

    10. Re:why not a simple rocket by Opportunist · · Score: 2

      Not as easy as it is on the drawing board. First, that rocket would have to be aligned EXACTLY with the center of gravity or all you accomplish is giving it a nice spin. Now, we don't even know for sure just what the asteroid is made of, let alone know the exact point of its COG. Many asteroids are anything but spherical, making the matter even worse. Considering how there is very little gravity acting on it, is it solid in the first place? Or composed of many smaller rocks held together by their gravity?

      But let's even assume that you manage to find out the COG. Now you have to not only land a rocket fairly softly on the rock, you also have to be able to provide thrust on the OTHER end, because you want to push TOWARDS the rock after landing on it. Now, rocket engines are not really lightweight, and putting a few pounds into space is already a feat and a half, and we're not even close to talking about having enough fuel left to push that rock. There is a reason that Saturn V was an effin' HUGE rocket that put a relatively tiny payload onto the moon. And that all only worked because the moon gravity is a tiny fraction of Earth's gravity (which is, btw, one of the big problems of a manned Mars mission, but I digress). And you now don't just want to put that payload, i.e. a few rocket engines and a fair lot of fuel, up the gravity well towards the Moon but most likely beyond that, because if the asteroid is already THAT close, I guess the amount of fuel necessary to even push it from hitting New York to hitting Los Angeles would be unfeasible. At the very least I'd estimate you have to intercept that rock halfway between Earth and Mars. But people with more background in gravity astronomy might provide more insight here.

      TL;DR version: We know too little about asteroids to push at the right spot, and putting an engine with fuel on an asteroid costs a damn lot of fuel.

      --
      We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
    11. Re:why not a simple rocket by Opportunist · · Score: 1

      Would be cool if that propellant could somehow be mined out of the asteroid itself. Kinda like pressing pellets of the asteroid soil and hurling it into space.

      Hey, how's that more crazy than shooting at it with paintball guns?

      --
      We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
    12. Re:why not a simple rocket by Nyeerrmm · · Score: 1

      Landing on a tumbling small body is not something you 'simply' do. Doing it to apply significant thrust is even harder due to center-of-gravity issues.

      A better way to have the same effect is to use a gravity tractor approach. By hovering away from the asteroid, you can use the gravitational attraction of the spacecraft on the asteroid in the same way. Since you'd need to use low thrust engines to get a significant amount of force over a reasonable time frame, the fact that the gravity tractor limits the amount of force you can apply is not too much of a constraint.

      However, the advantage of this painting method (we studied something similar in graduate school, the sticking point is how to get it to adhere to the surface) is that it requires the spacecraft to perform a one-time operation, but the effect is permanent, and over 50 or 100 years it could push an earth-crossing asteroid onto an orbit that was perfectly safe. If you could send one mission out to take care of a few of the more risky ones you could do it fairly inexpensively, assuming you figure out the material issues.

    13. Re:why not a simple rocket by Anonymous Coward · · Score: 0

      To be more quantitative, when you throw something at non-relativistic speed v, the momentum-to-energy ratio is 2/v, so you want to eject reaction mass as slowly as possible -- ideally just barely above escape velocity. Photons have a momentum-to-energy ratio of 1/c -- the smallest possible.

    14. Re:why not a simple rocket by Roachie · · Score: 1

      Because with paintball pellets we will have to put some goggles or a mask on the asteroid.

      --
      This sig is not paradoxical or ironic.
    15. Re:why not a simple rocket by jc42 · · Score: 2

      That's the issue. On the other hand, dropping paint on the asteroid provides thrust as if powered by a solar panel the size of the painted area, so paintballs > simple rocket.

      Well, maybe so, but there's another problem that nobody seems to have faced. Most of those asteroids are rotating, and they all have surfaces that are irregular at every scale. Unless you have very precise topo maps of the asteroid, down to the sub-millimeter scale, you won't be able to precisely calculae the direction of thrust of the paint splotches. And once a splotch is there, if its position is off by even a few cm, it's likely to produce a thrust in a different direction than you wanted.

      A rocket that lands and produces thrust would at least be controllable by turning it on and off at different point in the rock's rotation. That's a lot more control than you could get with paint splotches.

      If you want to use light pressure, I'd think you'd be far better off going with a flock of little light sails, which would land scattered over the asteroid's surface. Then you could send commands to precisely control which of the little sails are reflecting sunlight, and you'd actually be able to (slowly) make changes in the asteroid's orbit. That would probably be a lot more effective than paintballs or rocket motors.

      What am I missing about the paintballs that would make their "thrust" effect predictable and controllable? Without that, they might just steer the asteroid right into your house. Is there some paint that I don't know about, whose color we can control remotely from millions of km away?

      --
      Those who do study history are doomed to stand helplessly by while everyone else repeats it.
    16. Re:why not a simple rocket by symbolset · · Score: 1

      Dawn mission could have landed on Vesta, and would have but Ceres wanted a visit too. Dawn will likely land on Ceres. These are among the most massive asteroids, and most difficult to land on. Even a theoretical stony asteroid that has so much spin imparted by impacts that its surface gravity at the equator is negative has spin poles to land on. It is really not so hard to land on an asteroid, especially if you reserve a chemical rocket for the deorbit burn. It really doesn't need much.

      --
      Help stamp out iliturcy.
    17. Re:why not a simple rocket by ls671 · · Score: 1

      The more advanced version of this is steering the asteroid into orbit, then mining it.

      Do you mean planet Earth orbit ? If yes, it seems that it would require a lot of energy to slow the asteroids down first. I just do not see how it could just be steered into orbit.

      Speed is always the same for all objects orbiting Earth at a given altitude without regard for the mass of the object.
      Example speeds:
      At the Moon altitude 385,000 km: 1 km/s
      Geostationary altitude 36,000 km : 3 km/s
      Space Station altitude 360 km : 7 km/s
      Sea level 0 km: 8 km/s

      Asteroid speed is usually around 50 km/s.

      http://www.freemars.org/jeff/speed/index.htm

      --
      Everything I write is lies, read between the lines.
    18. Re:why not a simple rocket by Anonymous Coward · · Score: 0

      Giving a large push in roughly the right direction works. Giving a tiny push in exactly the right direction doesn't work.

    19. Re:why not a simple rocket by jc42 · · Score: 1

      Yeah, though it is interesting to contemplate the 3rd alternative: giving a tiny push in the right direction for a long time. Competent engineers can tell you when that'll work. Of course, it does require having the foresight to start pushing a long time before you're face-to-face with a disaster. And people working in large organizations don't have a good history of displaying such foresight.

      Various people have observed that we don't need to keep asteroids a long distance away from Earth. In fact, it could be a good show to change a big rock's orbit just enough that it skims the planet's upper atmosphere. Everyone would turn out to watch it, and it'd get across to the population that there are some Dangerous Things Out There that we'll eventually have to face. Right now, it's mostly just the techies (and the sci-fi fans) who take the problem seriously.

      --
      Those who do study history are doomed to stand helplessly by while everyone else repeats it.
  8. Too hard, just move the earth by Anonymous Coward · · Score: 0

    Have everybody sun-facing to hold up a mirror or something....

  9. Why would increasing the albedo... by taylormc · · Score: 1

    ...change the number of photons impinging on the asteroid, or increase their effect?

    1. Re:Why would increasing the albedo... by slashping · · Score: 3, Informative

      Increasing the albedo makes the photons bounce back, which requires a bigger change in momentum than just stopping them.

    2. Re:Why would increasing the albedo... by Altanar · · Score: 1

      While looking look up this effect, I found a neat article about a laser elevator on xkcd: http://blog.xkcd.com/2008/02/15/the-laser-elevator/

    3. Re:Why would increasing the albedo... by symbolset · · Score: 5, Interesting

      ...change the number of photons impinging on the asteroid, or increase their effect?

      A photon has energy. When a mass absorbs a photon's energy it has two effects: the mass increases in temperature equal to the energy of the photon, and the mass is accelerated in the direction of the photon's path equal to the energy of the photon. This seems like we're using the photon's energy twice, but it isn't so because thermal energy of a mass is kinetic energy shifted into the time domain. All objects in the solar system suffer this "solar wind" effect. The closer they are to the sun the more its radiated photons push them away. Obviously, the sun is emitting a LOT of photons.

      When the mass radiates the photon again it cools and is thrust again in the direction opposite the direction of the escaping photon. Depending on the rotation of the mass and the average time a photon is held before being emitted again (albedo), this can impact the course of the object. By changing the time factor you can cool the object and impact its trajectory. This is called the Yarkovsky effect. Dark or fast-spinning objects hold the photon's energy for so long that they are radiated in directions that are relatively random and have zero impact on course but they are hotter. Bright objects have more measurable impacts on course because the energy is released in a predictable direction that is relative to the input a vector related to the object's direction of spin but they are cooler. Believe it or not, you can use colors of paint to impact the period between absorption and emission, and use that to align the thrust opposite to the objects orbit around the sun, or in synergy with it. Our understanding of this effect has grown so great that we can tell an asteroid's mass, density, axis and rate of spin based only on its temperature and changes in its course.

      Derivatives of this feature are helpful in explaining the normal expansion of the universe (not inflation), as photons push masses on each end away. When we observe some galaxy 12 billion light years away, we're absorbing its photons and it's pushing on us ever so slightly.

      The difference can be illuminating. Radio Shack and others used to sell a heliotrope device that was a fan with reflectors on one side of the fins and black on the other. The relative difference in albedo would cause the fan to spin in any normal light.

      --
      Help stamp out iliturcy.
  10. Better off using marbles by Gothmolly · · Score: 1

    For the same weight, you'll transfer a lot more KE to the asteroid with a marble.

    --
    I want to delete my account but Slashdot doesn't allow it.
    1. Re:Better off using marbles by jklovanc · · Score: 1

      The KE is only a small part. The paint will increase the albedo of the asteroid therefore the thrust from the sun.

    2. Re:Better off using marbles by jo_ham · · Score: 1

      Is that weight under Earth gravity, weight during acceleration to the asteroid, weight during cruise, or weight while it's being fired at the surface?

    3. Re:Better off using marbles by oodaloop · · Score: 1

      Yes.

      --
      Tic-Tac-Toe, Global Thermonuclear War, and relationships all have the same winning move.
    4. Re:Better off using marbles by Nyeerrmm · · Score: 1

      The immediate transfer of kinetic energy is a small effect. The larger effect is a change in the albedo, particularly on a rotating asteroid, because that allows you to affect how the Yarkovsky effect is applied.

      When you change the Yarkovsky effect, it changes a force that is applied along the velocity direction, causing it to speed up or slow down: this is the most effective way to change the orbit in a way to avoid an impact. Because the force is applied for a very long period of time, it can avoid both the immediate impact risk and cause the object to move to an orbit that is permanently safe -- however, thats a 50 or 100 year effect.

      Of course this all applies to small asteroids. For a large one you're still left with with gravity tractors/explosives/etc.

  11. And a near miss? by edibobb · · Score: 1

    So I'd better hope the one that's headed for a near miss is black, so it doesn't curve and land on my house. It is senseless to worry about something with such infinitesimal odds, though. We should worry about the baggage retrieval system at Heathrow instead.

  12. We need better tracking first by runeghost · · Score: 3, Informative

    We've known that incoming (and outgoing - the Yarkovsky effect) radiation can alter an asteroid's trajectory for ages. But such a solution needs to be implemented far in advance of any pending impact. At present, we don't know the trajectory of potential impactors, like 9942 Apophis, to sufficient precision to make a deflection strategy like this useful. While it's true the odds are exceedingly small, accidentally putting an asteroid into a dangerous orbit would be disastrous. Apollo astronaut Rusty Schweickart proposed putting a tracking beacon on Apophis in order to further refine its orbit, which would allow us to use such gentle deflection strategies as the one outlined in the article. NASA turned him down. Fortunately, the Russians are currently planning a mission to Apophis; so maybe it will end up getting deflected via a generous application of paint.

  13. Long shot entrepreneurialism by macraig · · Score: 1

    I'm getting into the paintball manufacturing business on Monday. Look for my Kickstarter project, peoples.

  14. albedo sounds like libido!? by Anonymous Coward · · Score: 0

    pellets full of paint powder, launched in two rounds from a spacecraft at relatively close distance, would cover the front and back of an asteroid, more than doubling its reflectivity, or "libido"

  15. lasers! by Anonymous Coward · · Score: 0

    the right answer is always lasers!

    1. Re:lasers! by Anonymous Coward · · Score: 0

      the right answer is always lasers!

      Nope, blasters.

    2. Re:lasers! by Roachie · · Score: 1

      The problem with lasers is that you always seem to have to divert power from your shields and warp drive.

      --
      This sig is not paradoxical or ironic.
  16. Momentum transfer by GrahamCox · · Score: 1

    I'm not sure if I'm right, but my first thought was "surely the colour doesn't matter, since the momentum of the photons are transferred whether they are absorbed or reflected?". Perhaps someone with more knowledge of the relevant physics can answer.

    In any case, it seems like a very impractical proposal. Shouldn't students be given more useful topics to make studies of?

    1. Re:Momentum transfer by jamesh · · Score: 1

      I'm not sure if I'm right, but my first thought was "surely the colour doesn't matter, since the momentum of the photons are transferred whether they are absorbed or reflected?". Perhaps someone with more knowledge of the relevant physics can answer.

      In any case, it seems like a very impractical proposal. Shouldn't students be given more useful topics to make studies of?

      I'm not a physicist, but if the overall momentum of the system is constant, and we consider the original state of the system where a photon is headed towards the asteroid, then the alternate resulting states of the system are:

      1. photon is absorbed by the asteroid.

      2. photon is reflected by the asteroid and is now moving in the opposite direction

      and state 2 must have the asteroid moving slower relative to the direction it was hit by the photon to conserve the total momentum of the system.

      Of course photons travelling at the speed of light may not strictly obey newtonian physics, so I may be way off...

    2. Re:Momentum transfer by Anonymous Coward · · Score: 0

      I think the heating/radiating effect is what we're actually after here. Lets keep our eye on the ball, people.

  17. Asteroid deflectors will get FREE advertising! by crovira · · Score: 3, Funny

    Imagine your company logo emblazoned across the surface of an asteroid.

    Not only will your company have done something great for all mankind, but mankind will be reminded of it in perpetuity.

    First we paint the whole thing white and then get computer controlled pain ball guns to splatter, like an inkjet printer, your company's logo all over the asteroid.

    Think of watching a Papa John's ad every time you look up in the sky and having to say a little prayer that you can actually enjoy a large nutritious Papa John's pizza instead of having been reduced to a smokin' crater . :-)

    --
    MSBPodcast.com The opinions expressed here are my own. If you don't like 'em... Think up your own stuff.
    1. Re:Asteroid deflectors will get FREE advertising! by zammer990 · · Score: 0

      The inevitable problem is betting shops would offer really good odds on an asteroid not hitting the earth, and then have a big black square painted onto the asteroid

  18. Issues. by jklovanc · · Score: 2

    Timing;
    According to the article the paint would have to be applied 20 years before the asteroid approach. Add to that the time to get the craft to space, load up with paint and get out to the asteroid. That may take another 20 years. That may mean a 40 year lead time at launch to be remotely viable.
    Control
    Paint is not a guidance system. Sure it may be able to move the rock around but it will just be in an indefinite direction. It is just as possible to move the rock closer to earth as away. Sure it moves the rock away from earth but into a trajectory that interacts with a planet that pulls the rock back toward earth.
    Other celestial bodies.
    As other asteroids impact or come close to the "rock on question" they will alter the path. As the rock enters the Sol system planets will exert gravitational pull on the rock. The part or all 20 years of movement may be wiped out by interaction with another object.

    To me the only viable option would be to land thrusters on the rock. Use them to stop the rotation (if any), re-position to one side of the rock and apply constant thrust to alter the course. The thrusters would have to be ion based (low fuel, long duration) and probably powered by solar satellites. A solar sail could be added for additional thrust once the rotation has stopped. The issue with icy asteroids can be dealt with by limiting the thrust of the engines so as not to break the asteroid.

    If the rotation was not stopped it would require many more thrusters as they could only fire part of the time.

    This "proposal" sounds like "paint and pray".

    1. Re:Issues. by Anonymous Coward · · Score: 0

      The direction is definite it's -away- from the sun. You don't need to stop rotation... why do you think they suggested painting the front and back?

    2. Re:Issues. by Anonymous Coward · · Score: 0

      You've misunderstood a few things.

      Firstly, timing: we're doing such a good job of cataloguing the solar system that any civilisation-threatening chunk of rock *will* be spotted and known to be a threat decades in advance.

      Secondly, influence of other celestial bodies: other asteroids do squat. Their gravity is insignificant, and asteroid-asteroid collisions (movies notwithstanding) are so incredibly rare as to not be worth mentioning. The gravity of planets is significant, but is taken into account: when astronomers say that an asteroid is going to pass close to Earth, that's because they've projected its orbit ahead, figuring out all the gravitational influences from the planets, and found where it's going to go.

      Thirdly: given the above, and the careful balance of gravitational influences that would lead to an asteroid hitting Earth, *any* effect that changes its orbit is going to make it miss. It's possible that its new orbit will someday intersect ours, but no more likely than for any other asteroid in the solar system. And if we ever do figure out that it's going to do so, a million years down the line, all we need to do is paint it another colour and its course will change again. :-)

      (I'm actually serious that painting it another colour would work. If you paint it white, it'll experience the maximum possible force from solar radiation; if you paint it black, it'll experience the minimum possible force. So changing it either way - making it either darker or lighter - will change its course.)

      Source: I'm an astronomer. Not a solar system one, but I know enough of the basics to say the above.

    3. Re:Issues. by Anonymous Coward · · Score: 0

      They are already good at predicting about how close asteroids will pass us. They are unlikely to apply this procedure on any asteroids that are not fairly likely to hit us. Therefore, it is safe to assume that you can make the asteroid miss the earth no matter which direction it goes, as long as it moves far enough in that direction to give us a good enough safety margin. Even if the asteroid were to go directly toward the sun then the paint would simply slow it down, which would allow the earth to get out of the way.

      And considering that even Newton could predict the movement of the planets fairly accurately, I am surprised that you think that they can't predict how the planets will interact with possible asteroids even as long as 40 years into the future.

      In my opinion, a larger issue is rotation. We can only paint the side closest to us, so if that causes the asteroid to start rotating (or change its existing rotation), we might end up with a less predictable path.

    4. Re:Issues. by Anonymous Coward · · Score: 0

      There's no point in trying to stop the rotation of an asteroid. The amount of energy required for that is orders of magnitude larger than the amount of energy required to alter its orbit via a gravity tractor or similar "slow" technology assuming one has enough lead time.

  19. Society Of Protection of Asteroids by jamesh · · Score: 2

    The Society Of Protection of Asteroids (SOPA) will not stand for this. Anything that stands in the way of an asteroids natural path is against nature and against God.

    We're going to have to move the Earth out of the way instead... how much paint is that going to take?

    1. Re:Society Of Protection of Asteroids by Tablizer · · Score: 1

      I thought only dinosaurs belonged to SOPA?

      --
      Table-ized A.I.
  20. Ok in theory but there are better methods by Anonymous Coward · · Score: 0

    This would really only work for asteroids far out enough that a nuke detonated right next to them would move them enough. Also to launch a paint ball big enough to cover an asteroid that needs to be diverted would be half the size of the asteroid itself and any asteroids smaller than say a 3 story house would be burned up in our atmosphere and dont pose threat to require something like this to begin with so what they are talking about is a pair of paint ball big as the hubble and launching them at the front and back of a rock the size of a oil tanker or bigger... Oh and the launch mechanism would be the size of the iss and would have to be within spitting distance of the asteroid to begin with...

    Yeah i have seen anime with better ideas than this one (stratos 4)

    I think as far as a sustained method for redirecting a massive asteroid like this would be a pulsed ion drive so when ever the asteroid turned or rotated to a certain direction the pulse would go off and push the asteroid out of the path it was on or a pair of them one to get it spinning on an axis then another to push it after it is stabilized.

  21. energy content by Iamthecheese · · Score: 1

    I can't believe this would perform better pound for pound than high explosives

    --
    If video games influenced behavior the Pac Man generation would be eating pills and running away from their problems.
  22. I donno by Anonymous Coward · · Score: 0

    If an asteroid is coming our direction with the goal of a deep impact, I am not sure increasing its libido is a good idea

  23. Ice doesn't splatter by Anonymous Coward · · Score: 0

    How can this get past so many people. In order for paint to splatter and cover some thing it must be kept liquid which in space its ABSOLUTE ZERO. The paintballs will hit like rocks and bounce off.

    1. Re:Ice doesn't splatter by guttentag · · Score: 2

      In order for paint to splatter and cover some thing it must be kept liquid which in space its ABSOLUTE ZERO. The paintballs will hit like rocks and bounce off.

      It doesn't matter, because the amount of CO2 necessary to launch that many paintballs that distance would contribute so much to global warming we'd be better off taking our chances with the asteroid.

      What we really need is a giant tinfoil hat to enhance the asteroid's reflectivity and a North Korean missile guidance system to ensure it can't hit anything.

  24. movie trailer by Anonymous Coward · · Score: 0

    One destiny. One planet.
    In the biggest collaboration of human-kind in history.
    A team of brave scientists set out to device
    the biggest paint ball shooting spacecraft in history.

    Now read that with the movie trailer guy voice

  25. Remember by rossdee · · Score: 1

    When playing Paintball in space, you will be pushed backwards by the recoil too

  26. Frozen Paintballs by TheSwift · · Score: 2

    Among the many other problems already listed is whether or not paintballs will pop at 2.7 degrees kelvin.

    --
    "With patience a ruler may be persuaded, and a soft tongue will break a bone."
    1. Re:Frozen Paintballs by tftp · · Score: 1

      Among the many other problems already listed is whether or not paintballs will pop at 2.7 degrees kelvin.

      If you are going to apply the paint that far away from the Sun then yes, it will be a concern. Obviously, liquid paints will not work since only liquid Helium will be still liquid at that point. So you will need powder paints. The next question is how do you hold the paint there. Electric charge would be one interesting method, but will it last? Without some sort of adhesion the only force you have is gravity, and gravity of a small asteroid is also small. At least there is no atmosphere at that time to blow the paint away. (But as the asteroid comes closer, it is to be expected that the outer ice starts evaporating, and that will blow the paint off the surface.)

      All in all, I think this proposal is very hard to do technically. Just the amount of paint that we need to deliver would be astronomical. Forget the "size of Texas." If the asteroid is only 1 mile in diameter, it has surface of 87 million square feet. Let's say you need 50 grams of powder to "paint" one square foot. (I think it's on the low side.) The total mass of powder that is necessary to cover the asteroid will be then 4350 kg, or about 4.5 tonnes. Delivering that much mass that far from Earth is a challenge that is entirely comparable to delivering several ion thrusters along with nuclear-powered (RTG or fission or fusion) energy sources for them - esp. if we don't need much of shielding. Considering that the paint gives you zero control, and can actually make things worse, there is no advantage in using that method. No politician will go ahead with this plan if he can be blamed (correctly) for causing an asteroid that was going to miss Earth to not miss it.

  27. Deflect what? by user-hostile · · Score: 1

    Did anyone else read that as "Paintball Pellets As a Tool To Deflect Assholes?"

  28. This is asking for trouble by merxete · · Score: 0

    Better be careful. ... what about LOOOONG term affects of deflecting an asteroid? Sure, we'll be long gone, but is there downside to deflecting large bodies off their natural orbit, and disturbing the peaceful qi of the galactic universe.

  29. Water department ... by perpenso · · Score: 1

    The chances of getting killed by an asteroid are orders of magnitude larger than the chances of anyone in the world thanking us if we did manage to deflect one.

    I had an uncle who worked for the water department. I don't think anyone ever thanked him for the fact that numerous generations of people in the region have no knowledge of waterborne diseases. However he interpreted the ignorance of the public on such matters are evidence of a job well done, their ignorance was satisfaction in a strange way.

  30. Surface by Anonymous Coward · · Score: 0

    "Negative, it just impacted on the surface."

    Actually that was the point, negative nelly...

  31. White? by cmay · · Score: 1

    >you’d better hope that it’s blindingly white. No, If it blindingly white, it will already be reflecting sunlight, so then this won't work (unless we then painted it black, and cancelled out the natural effect). You'd hope for a dull asteroid so you could change it by making it blindingly white.

  32. MIT not as smart as you think by Gallomimia · · Score: 1

    I'd like to point out that in space paint pellets impacting with an object are really not going to behave as we all might assume. Perhaps a test of this system would be in order before surmising that it will cover an asteroid at all. I can just see the paint conserving momentum and being deflected away from the impact due to the lack of gravity and air. Like a really bad rendition of Deep Impact some blonde reporter getting on the TV to comment on the footage of our utter failure. Someone draw a trollface getting upset about it please.

    --
    Sadly, a Libertarian cannot force his views on another, and freedom cannot spread as does the cancer known as religion.
  33. What's Wrong with the Standing Solution? by bill_mcgonigle · · Score: 1

    Paintballs, eh? The big brains who work on this think that the best thing to do is to launch an ~2-ton spacecraft with an ion engine, position it near the asteroid, and let them do their gravity tango while the spacecraft very slowly changes the orbit of the pair. If it's a nice asteroid, that orbit is one that parks it in Earth's orbit for mining operations.

    As compared to painting the asteroid, if the asteroid tumbles at all (space dust, uneven heating, evaporation, etc.) the entire plan doesn't fall apart.

    --
    My God, it's Full of Source!
    OUTSIDE_IP=$(dig +short my.ip @outsideip.net)
  34. If it worked... by nilbog · · Score: 1

    If this worked other civilizations would have used it and every once in a while we'd see a painted asteroid go flying by. Right? RIGHT GUYS!?

    --
    or else!