back to article Official science: Massive asteroids are so difficult to destroy, Bruce Willis wouldn't stand a chance

Giant asteroids are harder to destroy than previously thought, according to fresh research out this month. “We used to believe that the larger the object, the more easily it would break, because bigger objects are more likely to have flaws,” explained Charles El Mir, first author of the study and a PhD graduate at Johns …

  1. Doctor Evil
    Pint

    If I understand this correctly, what they're saying is that when the big one hits the earth, there'll still be an earth afterwards (once all the bits re-coalesce -- see video 2). It just won't be recognizable as the earth per se. So, no problem, right?

    Thanks anyway for spending all that time thinking about stuff like this, you guys. Have one on me.

    1. Zonker Zoggs

      Think the simulations show the impact of a deterrent on the asteroid, not the asteroid on the earth, no?

    2. Bronek Kozicki Silver badge

      Actually, we are looking at the collision of two asteroids, and the bits which coalesce are the larger asteroid pulling itself back together (literally, by gravitational force) after the collision. Which means that if we tried to break apart a large asteroid on a collision course with Earth, this is likely to happen with the asteroid, if left for sufficient time.

      1. Kimo

        So we just split the asteroid in two, let each half pass on the opposite sides of the Earth, and then recombine on the other side?

        1. STOP_FORTH
          Mushroom

          That's a bit far-fetched, to be honest. You'd never get the two pieces matched up properly afterwards. Think of Airfix kits. Why not just compress asteroid until it's a black hole then watch it evaporate? Be quite pretty too!

    3. Jim Mitchell

      @Doctor Evil

      That is true enough for some size of impactor, however over a certain size (and under some other limit) you end up with a highly revised Earth and a second Moon. The odds of Ceres hitting Earth do seem low, though.

    4. asdf Silver badge

      > is that when the big one hits the earth

      We'll be long gone. Even NASA figured out pretty quick Yellowstone going boom is a far bigger threat than another dinosaur killer. Last time it blew covered the whole continent in a foot of ash (sure won't be pleasant on other side of pond either what with the nuclear type winter). Mt. Ranier flipping its lid and Cascadia fault rupturing in our lifetimes will simply be the warmup act.

      1. Charles 9 Silver badge

        How about the worst of both worlds: a dinosaur-killer striking the earth right at Yellowstone, setting off the supervolcano at the same time?

  2. SonOfDilbert
    Alert

    How much time would be needed?

    So, how much time would be needed for the core to gravitationally pull the debris back to itself? Surely in a situation with a direct collision path with Earth, this effect will be way too slow to matter.

    Also, when I run the experiment in my noggin, two massive rocks colliding at 5 km/s do much more than the youtube clip shows.

    1. imanidiot Silver badge

      Re: How much time would be needed?

      The results of hundreds of small rocks raining down through our atmosphere might be just as bad as a single big one. Of course the biggest question is if the trajectory is significantly affected. The goal is after all for the thing to miss the earth, not to smash it to bits.

  3. 9Rune5
    Boffin

    Of course not, you need the whole team

    Add Arnold and Sylvester, and I'm certain they'll get the job done.

    Sometimes scientists overthink things.

    1. John 110
      Mushroom

      Re: Of course not, you need the whole team

      They need the dream team of Chuck Norris and McGyver - that'll sort it!

      1. Version 1.0 Silver badge

        Re: Of course not, you need the whole team

        Don't forget Michael Bay, he'd make a big difference.

        1. DavCrav Silver badge

          Re: Of course not, you need the whole team

          "Don't forget Michael Bay, he'd make a big difference."

          Only if you just want explosions...oh, no, wait, never mind.

    2. MonkeyBob

      Re: Of course not, you need the whole team

      Wouldn't it be easier to send 1 Chuck Norris up, he'll smash it in one punch and all the little bits will be so scared they'll runn away.

      1. Charles 9 Silver badge
        Joke

        Re: Of course not, you need the whole team

        Are you confusing Chuck Norris with Saitama?

    3. Rafael #872397
      Go

      Re: Of course not, you need the whole team

      Shirley you mean Robert Duvall?

  4. Doctor Syntax Silver badge

    “We used to believe that the larger the object, the more easily it would break, because bigger objects are more likely to have flaws,”

    For a moment I hoped they were going to say they'd been up there tapping a sample with a hammer.

    Disappointment - it's just another simulaton.

  5. Tigra 07 Silver badge

    Does this mean a Death Star is now a more distant possibility than before?

    1. Steve K Silver badge
      Coat

      No, that's not a moon/asteroid

      No, that's not a moon/asteroid

    2. jmch Silver badge
      Gimp

      "Does this mean a Death Star is now a more distant possibility than before?"

      Well, DS is an energy weapon not kinetic. But if the same holds, it means instead of Alderaan being vaporised , it would be shattered into many chunks that eventually will pull back together to reform. Mind you, that's not much comfort to the Alderaanians.

      >>> does that count as darth Vader mask? >>>>>

  6. Baldrickk Silver badge

    Best option?

    Probably the best idea for dealing with a collision that I've seen is to send a drill up there, mine blocks of the asteroid and shoot it out the rear of the drill.

    Basically, use the asteroid itself as "reaction mass" (wrong word, I know) to cause a shift in the orbit, enough to turn a disaster into a near-miss.

    Quite how the launching of this rock would be achieved, wasn't really addressed though. Still, it seemed a fairly pragmatic approach.

    1. 0laf Silver badge
      Boffin

      Re: Best option?

      As I recall the sci-fi name for that is a 'Mass Driver'. And it has the potential to be effective due to Newtons laws.

      you'd just have to remember to point the rocks away from earth although depending on what they are made from you might want them in orbit nearby

      1. horriblicious

        Re: Best option?

        Unless you are talking about cutting off and launching rather large bits of the asteroid (and where are you getting the energy to both mine and launch a really big rock, repeatedly), it doesn't matter if they are pointed at earth. They will just be small chunks of rock that will burn up on re-entry.

        1. adam 40 Bronze badge
          Mushroom

          Re: Best option?

          Simples. You send up one nuke, and have it burrow into the asteroid.

          Detonate so it throws off a chunk at right angles roughly to direction towards Earth (you may have to wait for the spin to line it up and detonate at the right time)

          The smaller chunk then speeds off, and the larger chunk changed direction to miss the Earth.

          We supply the energy, and the asteroid supplies the propellant.

  7. Michael H.F. Wilkinson Silver badge
    Mushroom

    I would have thought that the bigger the rock, the harder it would be to shatter into completely harmless debris anyway. If the rock is big, the chances of seriously large chunks capable of seriously spoiling plans for the weekend would be higher than with smaller stuff, quite apart from the gravitational re-accumulation. Nudging a rock out of a dangerous orbit always seemed the more sensible, if not necessarily easy, option than going in with all guns blazing (which is the default Hollywood option for any problem, it seems).

    Icon, well, because an H-bomb will seem like a damp squib compared to a major asteroid strike.

    1. Twanky
      Alien

      So our choices are:

      - Massive shotgun blast

      - Massive single bullet

      - Dirigible asteroids (what could possibly go wrong?)

      We gotta get off this rock! Not all of us to the same place obviously.

    2. 100113.1537

      Surgical strike

      "Nudging a rock out of a dangerous orbit always seemed the more sensible, if not necessarily easy, option than going in with all guns blazing"

      The concept in Armageddon was that "all guns blazing" wasn't going to work for precisely the reason explained here. Blowing things up up the surface might nudge the thing, but not by much. Whereas by exploding the nuclear device inside the asteroid, the whole thing would split and the fragments would have different trajectories. This is a much more surgical approach - the way a small bomb can blow up a dam as long as it gets to the bottom of the lake before it explodes.

      The tension in the movie was actually created by the fight between the military who wanted to just blow the device and the engineers who wanted to get it into the core to be able to do it's job. I know it was just Hollywood, but from a scientific point of view the approach made sense.

  8. sum_of_squares
    Pint

    Whoa, stop right there!

    "Kilometres" and "seconds" in a scientific paper?

    Can't you give me that in quater-yardsticks per hourglass?

    1. Gio Ciampa

      Furlongs per fortnight please...

  9. Sorry that handle is already taken. Silver badge

    It's almost as if Hollywood doesn't understand gravity

  10. Duncan Macdonald Silver badge

    Escape velocity

    The escape velocity for a 25 km diameter asteroid (assuming it is spherical and the same density as the moon) is just slightly over 17 meters/sec (38mph). A lot of the blown off bits will have a velocity relative to the asteroid greater than this so will not be recaptured.

    (The impact energy is equivalent to over 9000 megatons of TNT (!!!) so the broken off bits will not be moving at slow speeds.)

    1. DavCrav Silver badge

      Re: Escape velocity

      "The escape velocity for a 25 km diameter asteroid (assuming it is spherical and the same density as the moon) is just slightly over 17 meters/sec (38mph). A lot of the blown off bits will have a velocity relative to the asteroid greater than this so will not be recaptured."

      Yes, but the total amount blown off would need to be greater than the big asteroid you've just added to the mass to be of any use. And the more you throw off very fast, the less energy there is to chuck off the rest. Slamming a small thing into a big thing won't smash the big thing into enough small fast bits, is the conclusion of this.

  11. simonb_london

    Chuck Norris

    Chuck Norris can destroy any asteroid.

  12. FrogsAndChips Silver badge

    So much for "Nuke it from orbit. It's the only way to be sure"...

    1. Gio Ciampa

      That was my 12-year-old mind's solution for all manner of issues ... almost a decade before James Cameron thought of it...

  13. ThatOne Silver badge
    Unhappy

    Throw theories at it until you deflect it?

    There are indeed several credible solutions to avoid a catastrophic asteroid collision, but the problem remains that, whatever they are, we're totally and definitively not ready to use them.

    We're still at the "maybe we could..." phase, haven't even tackled the problems of building anything. Unfortunately for us, it's only fair to say that said untested something, built in a hurry, has probably a rather slight chance to work as expected (or at all).

    The problem is that if one day we have to turn those ideas into something real and working, we will only have a very short time to do so. barely time for building, definitely no time for testing. Look how long it took mankind to reach the moon, I doubt any earth-bound asteroid will leave us that much time. More like days, or at best weeks I guess. Hardly the time for the preparatory meeting of the subcommittee election.

    1. Anonymous Coward
      Anonymous Coward

      Re: Throwing theories gets us there

      I think the most extreme example would be A/2017 U1 (search: A/2017 U1 Pan-STARRS).

      With our current monitoring system that 400 meter long space rock traveling at 25 kilometers per second (100 m–1,000 m × 35 m–167 m × 35 m–167 m @ 94,800 km/h) would have hit us without warning.

      But consider it's path (nasa has a nice animation). It came at us from the most unlikely and least monitored direction.

      And we did see it even if it was only as it was leaving.

      But for the largest and most likely threats humans have very good monitoring and are already tracking some objects that will not be a threat for decades or hundreds of years.

      As for lead time NASA claims it needs 5yrs but keep in mind that NASA is not the only expert agency. Other nations have landed on far away asteroids, and have more recently landed on the moon. We are ready and getting more ready as long as we can keep on advancing and avoid another dark age.

      For more and more accurate information search: B612 Foundation.

      1. horriblicious

        Re: Throwing theories gets us there

        If NASA thinks it can prevent a large asteroid impact with 5 years notice, I think they are in serious denial of the effort required. Yes there are missions to asteroids now - small vehicles with tiny payloads that take along time to get to the target. I am not a physicist, but whatever approach you take will require delivery of very large machinery (mass driver) or perhaps a sequence of very large bombs aimed to redirect rather than smash said asteroid. We are barely back to where NASA was in 1970 as regards lifting large objects into LEO (the space station). We do not yet have a vehicle with a large payload size that can leave LEO and head out to intercept an asteroid that might also be moving quite quickly. Thanks to SpaceX (and maybe NASA and the traditional rocketry companies), we might have some of the vehicles needed in the next decade or 2. We need to spot these things 20+ years out, or there will be nothing that can be done, and I am not so sure about 20 years.

        1. Mike Moyle Silver badge

          Re: Throwing theories gets us there

          We need to spot these things 20+ years out, or there will be nothing that can be done, and I am not so sure about 20 years."

          The problem with that theory is that the further out in time a fatal potentiality sits, the longer humans -- as a species, it would appear -- tend to spend their time denying/arguing/dithering/kicking the problem down the road/sticking their fingers in their ears and going "Lalala! I can't hear you! Lalalala!!" From the schoolboy putting off doing his homework until Sunday night to the "Climate change might be real but we can't afford what it will cost to solve it," politician, this problem seems to be hard-wired into humanity. It makes me think that the ONLY way that we'll solve the DinoKiller2.0 problem when it happens is by discovering it when it's too late to do anything but everyone throw everything they can at it in a massively-parallel set of individual last-minute Manhattan Projects and see what happens.

      2. ThatOne Silver badge
        Unhappy

        Re: Throwing theories gets us there

        > As for lead time NASA claims it needs 5yrs

        Well, remove at least one year for the solution to actually work (slowly deflecting the asteroid), that gives us just about the time to build rockets able to go beyond our moon's orbit (probably more than a couple of them), and whip out an untested prototype.

        Problem is, most ideas about deflecting an asteroid are pretty complicated, requiring technology we've never even tried before: Paint an asteroid? How do you paint in vacuum a gravity-less surface covered in gravel and dust? Most certainly requires some new and unheard-of technology? Mass driver? Sure, how many functioning at that scale have we ever built so far, and I'm not even going to go into the problems of installing and operating one on a distant asteroid. It would take some trial and error, and that's only after we have sent a probe to examine the offending asteroid thoroughly, and gathered a perfectly clear understanding of what it is made of and how it is internally structured (which might take most of a year all on itself).

        My point is if we had already managed to do a successful test run on some random asteroid, we could pretend we might potentially be able to repeat that feat in case of emergency. But right now the chances of success are slim, at best: New experimental, untried technology, fixed, very short deadlines, everything happening (hopefully) very far from earth, there is really nothing helping us here...

        1. horriblicious

          Re: Throwing theories gets us there

          It would be a very good thing if asteroid mining took off as a practical venture. It would be the place to try-out and prove many of the technologies you would need in an emergency. That looks to be a few years out too, but at least that is starting.

  14. Version 1.0 Silver badge
    Alien

    The Later Lite Bombardment?

    Sure, this sort of risk is worth scientifically evaluating but the chances of it happening are extremely low unless the oort cloud gets disturbed - occasionally a decent size chunk of rock will amble along but the chances of even getting one large enough to make a small crater are vanishingly small. Personally I think the risks to the planet come far more from human stupidity (climate change, politicians and social media idiots) than the occasional alien throwing stones at us.

    1. horriblicious

      Re: The Later Lite Bombardment?

      Low probability, but absolutely deadly and devastating. Disturbing the Oort cloud might divert more objects towards the inner solar system, but there are plenty already wizzing around to look out for.

      The "human-caused" problems you list are slow-moving, unlikely to be as devastating, and are subject to changes in human behavior. A big rock on a path to collide with Earth will not be swayed by protesters or clever editorials.

  15. VulcanV5
    Facepalm

    Health cure

    Here in the UK, I'm pretty sure you can get treatment for asteroids on the NHS. Doctors have known for quite some time now that a big asteroid is a bum deal, so this latest news really isn't that much of a surprise.

  16. Anonymous Coward
    Anonymous Coward

    At least the public is being told it isn't fiction.

    When it comes to breaking up in coming threats we always knew there would be a size limit.

    Although Hollywood likes the idea of breaking something up so the movie sky can be lit up for dramatic effect those working the science would only consider breaking up a large object a success if the pieces changed trajectory, or the reassembled object had a new trajectory.

    That someone is actively working on which solutions will work best for which objects is a very good thing for planet earth.

    Life on this planet has faced multiple extinction events caused by space rocks. That one of those more recent life forms is now able to protect all others from the next total extinction shows how adaptable life can be.

    Of course that new life form has to avoid it's own extinction before the next impact, something most life forms have been unable to do.

  17. 0laf Silver badge
    Mushroom

    I understand some of the more probably solutions involve attaching large solar sail type thingies to an asteroid and using the pressure of light from the sun to move the orbit of the embuggerance very slowly over a period of years or decades. Everything stays together that way.

    The earlier you spot it the less effort you need to put in.

    1. vtcodger Silver badge

      I think you could just spray a coat of reflective paint on the thing and achieve the same effect as attaching a solar sail. ... BUT ... I think one would need a LOT of lead time. And tracking/ orbit prediction software of extraordinary capability. You'll get no end of criticism if you inadvertently steer a rock that was going to miss the Earth into the North Atlantic. And there is, of course, the question of designing a paint sprayer that will work in space and creating a paint that will coat surfaces that are either exposed to direct sunlight with no atmospheric attenuation or are really, really cold.

  18. Tim Soldiers

    Stick a rail gun on the moon. Just keep hitting any asteroid till it moves or breaks .. simple surely

    1. horriblicious

      It is a great and simple idea. Of course, we need to wait until we figure out how to build one big enough to make a difference. Well, that or build a Death Star.

  19. DougS Silver badge

    I didn't think anyone serious still believed "blowing it up" was a viable plan

    Even if you could blow it into a million pieces, you'd have a million meteorites striking the Earth and likely doing a lot more damage.

    The only hope is to move it out of the way, via one of the various suggestions on how to accomplish that. Which means we need to find out about a "doomsday asteroid" years in advance, to give us time to send several simultaneous missions[*] to it.

    [*] I'd feel more comfortable if we tried multiple plans such "paint one side of it", turn it into a rocket", "gravity assist" etc. all at once, though they'd obviously need to be carefully coordinated so they aren't working against each other.

    1. horriblicious

      Re: I didn't think anyone serious still believed "blowing it up" was a viable plan

      Small meteorites are "small" - well, you will get a range of sizes but all smaller than the original asteroid. The damage from some fraction of those that would survive passing through Earth's atmosphere is surely minor in comparison to a direct hit by the entire asteroid. I do like the "multiple coordinated plans approach" to divert it though.

      1. DougS Silver badge

        Re: I didn't think anyone serious still believed "blowing it up" was a viable plan

        "Small" is relative. You aren't going to blow up a mile wide asteroid into chunks small enough to burn up in the atmosphere. Rather than one spot that is completely destroyed for 50 miles in all directions (or whatever) you'd have thousands of spots that are completely destroyed for a mile in all directions. Plenty of them would probably be of the right size/shape to explode in the air like that one in Russia, only much larger and more comparable to Tunguska than Chelyabinsk in result.

        It isn't as though there is any method by which we can blow up a thousand ton boulder into gravel size chunks. You'd get dozens of multi ton boulders, and countless various smaller rocks. If you went nuts on the explosive force you might keep everything under a ton but you still won't get gravel. If we can't do it in the small scale, we sure as heck can't expect to do it in a larger scale. In space.

        1. horriblicious

          Re: I didn't think anyone serious still believed "blowing it up" was a viable plan

          Yet surely the damage from many of those smaller pieces is far preferable to the damage that would be caused by the asteroid in one piece? Much will land where there are no people - 2/3 of the surface is ocean and the land surface is surprisingly empty as well. It will still cause damage, but in the absence of a perfect solution many smaller chunks sounds "good enough" as an alternative.

          1. Charles 9 Silver badge

            Re: I didn't think anyone serious still believed "blowing it up" was a viable plan

            Plus wouldn't blowing them into smaller chunks increase the overall surface area, making them prone to taking more damage and wear from atmospheric entry?

      2. doctornasty

        Re: I didn't think anyone serious still believed "blowing it up" was a viable plan

        perhaps something like the propulsion charges for project Orion..?

  20. drewsup

    Kinda makes sense

    A larger asteroid would survived multiple gravitational encounters , it's Darwinism in space, only the toughest get big.

  21. STOP_FORTH
    Holmes

    They are doing this all wrong

    Move the Earth out of the way. It is also easier to experiment on the Earth, what with it being here already.

  22. the Jim bloke Silver badge

    But you said asteroids were soft, and fluffy....

    see article

    https://www.theregister.co.uk/2017/12/11/earth_atmosphere_final_defense_against_meteorites/

  23. Cynical Pie

    Doomed, we're all doomed I tell you...

  24. STOP_FORTH

    Space Invaders

    Learn from the masters - Space Invaders.

    Hide behind Moon from hostile invaders, then nip out and zap them with laser torpedoes.

    Pew-pew! Job's a good 'un.

    Of course deflecting them to the far side of the moon might be tricky, but it would have the added benefit of zapping all of the Iron Sky volk living there. Or, if that seems too harsh, get them to build a rail gun. Mebbe mount it on a Zeppelin?

    Well, now I have solved that minor problem, I'm going to have a jolly thorough look for my radiator key.

  25. doctornasty

    The reason it looks weird? they forgot escape velocity.. a rock the size of phobos has an escape velocity of 30mph..I have a suspicion that a lot of those fragments are going a bit faster than that.

  26. Conundrum1885 Bronze badge

    If you want to stop an asteroid

    Put PM May on a rocket armed with her latest Brexit deal. The asteroid will change course to avoid her!

    Note: Only works up until March 29th 2019 at 11pm BST then all bets are off.

    Hypothetically about 2 grams of antimatter would effectively demolish a medium sized (8mi) asteroid.

    This scales to about 2-3 Tsar Bomba sized warheads with maximum >100MT yield, to divert it assuming its 5 months out

    or more. If its any closer than this we have bigger problems unless DARPA have an Orion MiniMag powered ship up their sleeves.

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