World Destroying Asteroids Aren't Necessarily Held Together By Gravity

World Destroying Asteroids Aren't Necessarily Held Together By Gravity

Asteroid 1950 DA, a kilometre-long object that could hit Earth, is basically a group of rocks held together by van der Waals forces.

Science takes its study of interstellar asteroids pretty seriously, partly because they contain resources that might help humanity, and partly because one could wipe out all life on Earth. Consider 1950 DA, a kilometre-sized asteroid with a fairly high chance of hitting the Earth in 2880. While "relatively high" isn't the same thing as "we're all gonna die", astronomers are keeping a close eye on it just in case. From these studies, they've gleaned something interesting: 1950 DA is basically a pile of rubble that isn't held together by gravity at all.

Previous studies have suggested that some asteroids are a loose collection of space junk instead of a cohesive rock; even our own moon may be a combination of Earth and space debris. Scientists presumed this rubble-pile asteroids were held together by gravity and friction, but that simply cannot be the case with 1950 DA. This asteroid is rotating so quickly that it should be negating gravity and disintegrating, flinging its body apart in the process. Instead, the asteroid may be held together by van der Waals forces, a bond between individual molecules. You've probably seen van der Waals forces in action on Earth; it's the same phenomenon that lets geckos walk along walls and ceilings.

But what does this mean for scientists studying asteroids? Well, if 1950 DA is about to hit the Earth, firing rockets wouldn't deflect it. Instead, the whole thing would disintegrate and Earth would be hit by multiple asteroids instead of a large one. It also means that if astronauts want to land on it, whether to deflect it or mine for resources, the spin could potentially fling them from the surface. Even if it doesn't, disturbing the surface of the 1950 DA just a little might cause the disintegration effect.

Now, breaking up an asteroid into smaller pieces wouldn't be so bad if they just burst in the atmosphere, which happens all the time. But what's more likely to happen is that we'd need to shoot down multiple killer space rocks like it's an real-life game of Asteroids. Some other solution would be needed, but on the bright side, at least we have over 800 years to figure it out.

Source: Nature, via Tech Times

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...And after all
You're my van der Waal...

That is really the only thing that came to my mind after reading this.

Tired of seeing scientific term and items named after people.

The Periodic Table is the worst at this. One wonders how bland and inane science might have been had vain scientists been doing this since the 1500s.

beastro:
Tired of seeing scientific term and items named after people.

The Periodic Table is the worst at this. One wonders how bland and inane science might have been had vain scientists been doing this since the 1500s.

Dude, we're working 50 to 90 hour weeks for a stupidly low salary after 8 to 10 years of college, our work is spat upon by the public, ignored by politicians and exploited by industrials.

So leave us our only damn reward: leaving a mark in a way that the general public will see probably a hundredth times less than their average TV speaking head who makes ten times as much with ten times less work.

In relation to the article, of course you can nuke the thing, turn it into a cloud of debris and save the Earth. The trick is simply to do it early enough that by the time the cloud of debris reaches Earth, it has already dispersed enough to not hit us.

*799 years in the future*

SHIT! Why did we leave this till the last minute, any ideas!?

Rockets?

No, our great, great, great, great, great, great, grand parents discussed this!

Rufus Shinra:

beastro:
Tired of seeing scientific term and items named after people.

The Periodic Table is the worst at this. One wonders how bland and inane science might have been had vain scientists been doing this since the 1500s.

Dude, we're working 50 to 90 hour weeks for a stupidly low salary after 8 to 10 years of college, our work is spat upon by the public, ignored by politicians and exploited by industrials.

So leave us our only damn reward: leaving a mark in a way that the general public will see probably a hundredth times less than their average TV speaking head who makes ten times as much with ten times less work.

In relation to the article, of course you can nuke the thing, turn it into a cloud of debris and save the Earth. The trick is simply to do it early enough that by the time the cloud of debris reaches Earth, it has already dispersed enough to not hit us.

If you're in the job for reasons of vanity, you picked the wrong job.

Yeah, such a shame those industrialists make practical use of your discoveries, how dare anyone do that.

beastro:

Rufus Shinra:

beastro:
Tired of seeing scientific term and items named after people.

The Periodic Table is the worst at this. One wonders how bland and inane science might have been had vain scientists been doing this since the 1500s.

Dude, we're working 50 to 90 hour weeks for a stupidly low salary after 8 to 10 years of college, our work is spat upon by the public, ignored by politicians and exploited by industrials.

So leave us our only damn reward: leaving a mark in a way that the general public will see probably a hundredth times less than their average TV speaking head who makes ten times as much with ten times less work.

In relation to the article, of course you can nuke the thing, turn it into a cloud of debris and save the Earth. The trick is simply to do it early enough that by the time the cloud of debris reaches Earth, it has already dispersed enough to not hit us.

If you're in the job for reasons of vanity, you picked the wrong job.

Yeah, such a shame those industrialists make practical use of your discoveries, how dare anyone do that.

This is a perfect example of how scientists are some of the most under-appreciated people in society.

beastro:

Rufus Shinra:

beastro:
Tired of seeing scientific term and items named after people.

The Periodic Table is the worst at this. One wonders how bland and inane science might have been had vain scientists been doing this since the 1500s.

Dude, we're working 50 to 90 hour weeks for a stupidly low salary after 8 to 10 years of college, our work is spat upon by the public, ignored by politicians and exploited by industrials.

So leave us our only damn reward: leaving a mark in a way that the general public will see probably a hundredth times less than their average TV speaking head who makes ten times as much with ten times less work.

In relation to the article, of course you can nuke the thing, turn it into a cloud of debris and save the Earth. The trick is simply to do it early enough that by the time the cloud of debris reaches Earth, it has already dispersed enough to not hit us.

If you're in the job for reasons of vanity, you picked the wrong job.

Yeah, such a shame those industrialists make practical use of your discoveries, how dare anyone do that.

Wanting to see a little recognition isn't vanity, scientists of all kinds from the lab techs to the most famous discoverers have shaped our world and improved our lives. Having a significant discovery or theory named after them is the least society can do to recognise that.

Fanghawk:
basically a pile of rubble that isn't held together by gravity at all

NO. No no no no no.

1950DA is spinning very slightly faster than could be held together by gravity alone, and its hypothesised that the tiny additional force helping keep it together is van der Waals force. Saying it isnt held together by gravity at all is just nonsense. Of course gravity is a major factor on objects in space. If it wasnt, the headline for this article wouldnt be about asteroids, it would be "scientists overturn the fundamental laws of physics".

Caffiene:

Fanghawk:
basically a pile of rubble that isn't held together by gravity at all

NO. No no no no no.

1950DA is spinning very slightly faster than could be held together by gravity alone, and its hypothesised that the tiny additional force helping keep it together is van der Waals force. Saying it isnt held together by gravity at all is just nonsense. Of course gravity is a major factor on objects in space. If it wasnt, the headline for this article wouldnt be about asteroids, it would be "scientists overturn the fundamental laws of physics".

Pretty much what he said. Gravity and spin is much of the reason the universe looks and acts the way that it does. Another large chunk of it is the effect of dark matter, of which essentially a halo of is encircling the solar system in a manner that actually helps it keep together. This force is wedged somewhere in between all that, relevant, but not in of itself the only factor.

If you want to find out for certain, why don't you go fling a missle over at an asteroid that is Very Definitely Never Going To Hit Earth and study the effects? Granted, that could take a very long time AND alot of calculations, but let us not forget the Scientific Method. You have here a hypothesis which could actually mean life and death. For something like this, it's best to find a way to prove or disprove it before it's too late.

Incidentally, if they're really that worried about being assaulted by asteroid bits after a disruption, calculate a pattern of missles to explode in a manner allowing overlapping blast-radiuses, effectively like an explosion net with no real gaps. IF the angle and trajectory of the missles is decent enough, the explosions - and more importantly their collective shockwaves - should push an asteroid, be it in bits or largely whole, AWAY. Perhaps in alot of directions, but AWAY from Earth. In effect, it would be a very large push and take alot of missles, but GOD KNOWS we have a ton of them on this planet!

beastro:
If you're in the job for reasons of vanity, you picked the wrong job.

Yeah, such a shame those industrialists make practical use of your discoveries, how dare anyone do that.

Excuse us for wanting to be a little bit recognized for our work. I admit it's the height of arrogance for us to bother the non-scientists once in a blue moon by having a weird name in a paper you guys will forget anyway in the next fifteen minutes.

Not like you'll have the name of some actors or stuff printed everywhere on the buses or the ones of politicians shouted on radio stations 24/7, right?

image

(Addendum: the "Politician" line is undistinguishable from the "Fame" axis, as no Skill is required at all to achieve celebrity there, though recent work indicate that the correlation to skill would actually be negative - see "Politics in the United States", "Creationism" and "Institutional Idiocy" for more details)

J Tyran:
Wanting to see a little recognition isn't vanity, scientists of all kinds from the lab techs to the most famous discoverers have shaped our world and improved our lives. Having a significant discovery or theory named after them is the least society can do to recognise that.

Thanks.

FalloutJack:
Incidentally, if they're really that worried about being assaulted by asteroid bits after a disruption, calculate a pattern of missles to explode in a manner allowing overlapping blast-radiuses, effectively like an explosion net with no real gaps. IF the angle and trajectory of the missles is decent enough, the explosions - and more importantly their collective shockwaves - should push an asteroid, be it in bits or largely whole, AWAY. Perhaps in alot of directions, but AWAY from Earth. In effect, it would be a very large push and take alot of missles, but GOD KNOWS we have a ton of them on this planet!

One: we don't have a ton of missiles able to reach asteroids. The only ones able to do so are massive rockets the size of Proton or Ariane 5, etc.
Two: any direction is away from Earth, in this kind of scenario. If you accelerate the asteroid, it will miss by intercepting Earth's orbit before Earth is at the right point. If you slow it down, it will miss too. If you nudge it on the side, it will miss.

The one and only objective you have is to ensure that the rock or the big debris will move at least an additional six thousand kilometers in any direction between the strike and the predicted collision time. If that condition is checked, then no impact.

If you intercept the asteroid ten years before the predicted impact (which can be much easier than it seems, as asteroids are orbiting the Sun and might come close to Earth before going away and going back to hit), then all you need is to give everything an awesome speed of... 1.9 centimeter per second. That's it. Give the rocks 5 cm per second in whatever direction and they'll miss.

Of course, Bruce Willis will be hailed as the big damn hero while the NASA/ESA/JAXA/Russian/Chinese scientists who made the whole mission possible will only be gifted a new coffee machine or so.

(one of these days, we're just going to turn the LHC against the governements, fire an antiproton beam at Hollywood and take over the world)

Rufus Shinra:
Voip

Weirdly, it sounds like you're both agreeing AND disagreeing with me. So, is the task insurmountable because of the missle build or incredibly easy because you're certain it needs only a (relatively) small poke of doom? I just want to be sure here.

Rufus Shinra:
Of course, Bruce Willis will be hailed as the big damn hero while the NASA/ESA/JAXA/Russian/Chinese scientists who made the whole mission possible will only be gifted a new coffee machine or so.

If anything, the public view of science is getting worse thanks to global warming denial..

Rufus Shinra:
(one of these days, we're just going to turn the LHC against the governements, fire an antiproton beam at Hollywood and take over the world)

Dude! I know the miniature-black-hole-consuming-the-earth thing is currently making excellent progress but you can't get cocky and just give away plan B.

FalloutJack:

Rufus Shinra:
Voip

Weirdly, it sounds like you're both agreeing AND disagreeing with me. So, is the task insurmountable because of the missle build or incredibly easy because you're certain it needs only a (relatively) small poke of doom? I just want to be sure here.

In theory it's easy.

You just have to nudge it sufficiently early (depending on the power of your rocket).

In the real world however it's a bit harder.

The only rockets that we have which can actually make the journey are few, and they're so incredibly expensive that we don't really have a stockpile, but rather build them as we need them.

Take a look at the price for an Atlas-V, an Ariane-5, or a Proton-M rocket for example.

If we don't have the ability to handle asteroids in 800 years then methinks the problems at home may be more serious than even that.

Lightknight:
If we don't have the ability to handle asteroids in 800 years then methinks the problems at home may be more serious than even that.

If we're not off this rock in, at /minimum/, a fleet of self contained mobile habitats capable of exploiting interstellar materials like 1950 DA to meet basic needs in 800 years, I'm going to be very disappointed in us.

Not mad.

Just disappointed.

OH NOE!! Space geckoroid comin to kill us all.. or latch on to us....

NNNOOO!!1

FalloutJack:

Rufus Shinra:
Voip

Weirdly, it sounds like you're both agreeing AND disagreeing with me. So, is the task insurmountable because of the missle build or incredibly easy because you're certain it needs only a (relatively) small poke of doom? I just want to be sure here.

If you get there early enough, shoving the stuff is quite easy. A few high-yield nukes pack much more energy than what you need to push the asteroid outside the... *puts his sunglasses* Danger Zone.

The problem is getting there. You need to give your high-yield nukes something around 12 to 15 km/s just to make sure you'll be able to reach your target. And then, if you want to reach it sooner, or, Celestia forbids, reach it sooner AND synchronize properly the orbits for a soft landing before the big bang, you'll need even more.

Here is the rocketry map to the solar system: http://i.imgur.com/AAGJvD1.png

To get your package to orbit, you need to give it around 9.4 kps. A balistic missile, the ones that share a lot of sunshine with your friends around the world, will not give that speed. They will take off and fall down (probably somewhere around their intended target). For this, you need bigger stuff or smaller payloads. So, we're in orbit, right? Well, you can take photos, see the asteroid kill your friends, your family and your dog, cry a little bit, sleep with the female lead character (or male, whatever), and then die. Because, duh, you were in orbit and nowhere else.

To get out of orbit, you need an additional 3.2 kps. Now, congrats, you are your own celestial body circling around the Sun. Wheeeeeeee! Like Jebediah Kerman, you'll smile and smile and smile and smile forever. The Earth still gets destroyed.

Now, you need an additional impulse to get an orbit that will cross the trajectory of the rock, hopefully soon enough that your package is enough to save the world.

You reach the rendezvous point and... you fly away after a very brief instant to take a picure before you cruise away. Unless you spent additional speed to synchronize your orbits and burn out that relative speed.

Congrats, you're on the rock. Now pray that enough nukes will work, 'cause the repairman ain't going to come to fix that fu**ing loose red wire.

BOOM, big, silenced, shockwave-less flash, the rock gains a few cm/s of additional speed in whatever direction, the Earth is saved. The scientists get their new coffee machine.

Now, if the craft was remote-controlled, end of the movie. It will come back in a few years, as you were precisely on an impact trajectory yourself. If the craft is crewed... well, I hope you've good some snacks and a good stash of eBooks, 'cause you're going to wait for long until you get back. Oh, and hope that you still have fuel to slow down before impacting Earth.

This is it. Entirely doable. The European Space Agency just intercepted a comet last month, with the probe in orbit around the comet, ready to send an impactor and absolutely not claim that rock as a European colony, no Sir, absolutely not. So we know the stuff. Just need enough time in advance to make sure it works.

All I'll say is this is the first time I hear about the van der Waals forces working on any scale larger than the order of magnitude of molecules, but I do admit I haven't checked in a while.

Vegosiux:
All I'll say is this is the first time I hear about the van der Waals forces working on any scale larger than the order of magnitude of molecules, but I do admit I haven't checked in a while.

It's still working on the molecular level. The same way a gecko lizard can climb up a sheer glass surface.

There is friction being generated at the molecular level between debris. So the force is still at the molecular level even if we can see the effects of it in the macro level.

 

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