Space dust reveals Earth-killer asteroids would be tough to destroy
- Reference: 1674628211
- News link: https://www.theregister.co.uk/2023/01/25/space_dust_asteroid/
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Measuring 330 metres across, Itokawa is the first-ever asteroid to be sampled in a space mission. Japan's Aerospace Exploration Agency launched its Hayabusa 1 probe in 2003 to study Itokawa, and managed to [1]return about a milligram of stuff taken from the asteroid's surface to Earth seven years later.
Now, an international team of researchers led by Curtin University, Australia, has studied three dust particles from the sample to estimate Itokawa's age and disposition. Argon dating revealed the asteroid is older than 4.2 billion years, and has been described as having a cushion-like structure. The team discovered Itokawa is older and tougher than previously thought.
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"Unlike monolithic asteroids, Itokawa is not a single lump of rock, but belongs to the rubble pile family which means it's entirely made of loose boulders and rocks, with almost half of it being empty space," Fred Jourdan, lead author of the research [3]published in the in the Proceedings of the National Academy of Sciences and a geochemistry professor at Curtin University, said in a [4]statement .
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The gaps make rubble pile asteroids good at absorbing the shock from collisions. "We found that Itokawa is like a giant space cushion, and very hard to destroy," Jourdan added. Itokawa was originally formed from a monolithic ancient asteroid that fractured into pieces after a violent collision. Bits of leftover rock and dust coalesced into a rubble pile under gravitational forces to create Itokawa.
"Now that we have found they can survive in the solar system for almost its entire history, they must be more abundant in the asteroid belt than previously thought, so there is more chance that if a big asteroid is hurtling toward Earth, it will be a rubble pile," said Nick Timms, co-author of the paper and geology professor also from Curtin University.
[7]Don't panic: An asteroid larger than the Empire State Building is flying past Earth this weekend but we're just fine
[8]Lucy asteroid probe forced to limp on without full solar array
[9]The cubesats lost in space from Artemis Moon mission
[10]Water big surprise: H 2 O found in samples of 'dry' asteroid brought to Earth over millions of miles by plucky probe
He believes that studying these types of space rocks in more detail will help space agencies around the world develop strategies to prevent potential collisions. Since Itokawa would be difficult to destroy, creating a diversion may be a better way to steer it away from Earth.
"The good news is that we can also use this information to our advantage – if an asteroid is detected too late for a kinetic push, we can then potentially use a more aggressive approach like using the shockwave of a close-by nuclear blast to push a rubble-pile asteroid off course without destroying it," he said.
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Last year, NASA [12]demonstrated it was possible to knock an asteroid and change its orbit using kinetic impact in its DART mission. Lindley Johnson, NASA's Planetary Defense Officer, who helped lead the DART mission, [13]previously told The Register that a potentially hazardous asteroid needs to be nudged about 8,000 miles to safely move it beyond the radius of Earth and outside of the danger zone. "That can easily be accomplished a year or two in advance," he said. ®
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[1] https://www.pnas.org/doi/10.1073/pnas.2214353120
[2] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=2&c=2Y9EL0vSAx2agOegUjX8K@QAAAMg&t=ct%3Dns%26unitnum%3D2%26raptor%3Dcondor%26pos%3Dtop%26test%3D0
[3] https://www.pnas.org/doi/10.1073/pnas.2214353120
[4] https://www.curtin.edu.au/news/media-release/asteroid-findings-from-specks-of-space-dust-could-save-the-planet/
[5] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44Y9EL0vSAx2agOegUjX8K@QAAAMg&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0
[6] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=3&c=33Y9EL0vSAx2agOegUjX8K@QAAAMg&t=ct%3Dns%26unitnum%3D3%26raptor%3Deagle%26pos%3Dmid%26test%3D0
[7] https://www.theregister.com/2020/06/06/dont_freak_out_but_an/
[8] https://www.theregister.com/2023/01/24/nasa_lucy_probe/
[9] https://www.theregister.com/2022/12/12/artemis_science_payload/
[10] https://www.theregister.com/2019/05/03/water_in_asteroid/
[11] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44Y9EL0vSAx2agOegUjX8K@QAAAMg&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0
[12] https://www.theregister.com/2022/09/27/dart_nasa_asteroid_oimpace/
[13] https://www.theregister.com/2022/09/24/dart_spacecraft_asteroid_nasa/
[14] https://whitepapers.theregister.com/
"...a giant space cushion ... hard to destroy..."
Send the Space Puppies.
Well I've read all I needed to read about this asteroid to know that dry January can f**k off right now.
Strike!
> it's entirely made of loose boulders and rocks
So what is needed is a bowling champion to plot exactly what path an incoming "bowling ball" would need to take to scatter all the largest rocks onto different vectors. Maybe they would all hit Earth at some point, but I suspect lots of little space rocks falling in geographically dispersed areas is better than one large one.
Re: Strike!
It depends on the timescale over which the bits enter the atmosphere. If you were to take all of the rocks and dust that enter the atmosphere in a year, stick them all in one ball, and throw them at the atmosphere in one go then you would see a very significant event. So if you can take your asteroid and turn it into a smear of rubble that enters the atmosphere over a number of weeks then the planet would barely notice.
But if you expand your asteroid into a cloud that hits all at the same time then the concentration of energy imparted to the atmosphere will mean that the event would be pretty much similar to the original asteroid hitting instead. The altitude and distribution of energy would likely vary but the amount over a short period of time would not.
I could go on thinking about different scenarios and the effect they would have, but I'm afraid I have some of the 'W' word to do.
shockwave of a close-by nuclear blast
What medium do they expect that wave to be propagated in?
Freshly vaporised nuclear missile.
Dig a hole
If it is a rubble pile, it should be easy to first bury the warhead a meter or so below the surface. Then the explosion will kick vaporized rock and dust as reaction mass.
The space rocks argon
This article doesn't say how large the boulders are. Will they just provide pretty blinkenlights as they fall from the sky or will there be a big KABOOM? At least they are good at absorbing impact, so we won't have to. I just watched a whole lot of UnchartedX on YouTube about the Younger Dryass impact, etc. I want to know if it will be necessary to start building all sorts of big and weird granite stuff for future civilizations to find after ours is wiped out?
"like using the shockwave of a close-by nuclear blast to push a rubble-pile asteroid off course without destroying it." I was under the impression that if you don't have an atmosphere you can't have a shockwave? Surely you need a medium for a wave to propagate through, which certainly isn't space.
As someone mentioned above, freshly-vapourised nuclear missile casing.
Also thermal radiation. If you warm up the surface of an object so that it outgasses (possibly by evaporating some rock), the outgassing will act like a rocket.
the outgassing will act like a rocket
How much gas, how quickly, what force ? I suspect that most of the heating will be absorbed by the rubble/sand/... close to the nuke, some of it will be vaporised. So some material will be made to move but most of it very little. The result will be that it bulges for a bit but most of it will still hit us.
After a few years gravity will have pulled it all together again.
Why not going full Bruce Willis?
What's wrong with nuclear weapons?
The Soviet Lake Chagan needed just a 140 kiloton weapon. Take a megaton range warhead, attach it to a penetrator, and you have an asteroid killer. You can even send two or three warheads once after each other to create a hole and then make the hole bigger. Targeting would be difficult but manageable with enought resources put into it.
Litter Bugs
Those damn Vogons, just fly-tipping again!