Arthur T Knackerbracket has processed the following story:
The DART spacecraft’s collision with its target may leave the asteroid unrecognizable, rather than just a minor crater.
The world’s first comprehensive planetary defense test against potential asteroid impacts on Earth is being conducted by NASA as part of the Double Asteroid Redirection Test (DART) project. Researchers from the University of Bern and the National Centre of Competence in Research (NCCR) PlanetS have now shown that the impact of the DART spacecraft on its target might render the asteroid almost unrecognizable rather than leaving behind a relatively tiny crater.
The extinction of the dinosaurs is thought to have occurred 66 million years ago as a result of a massive asteroid collision on Earth. No known asteroid presents an immediate danger right now. But if a large asteroid were to be found one day headed straight for Earth, it might need to be diverted off its route to avoid disastrous consequences.
The DART space probe, developed by NASA in the US, was launched last November as the first full-scale test of such a maneuver. Its goal is to hit an asteroid and divert it off its orbit in order to gather important data for the creation of a planetary defense system.
Researchers from the University of Bern and the National Centre of Competence in Research (NCCR) PlanetS used a new method to model this impact in a recent study that was published in The Planetary Science Journal. According to their findings, it may damage its target far more severely than previously believed.
“Contrary to what one might imagine when picturing an asteroid, direct evidence from space missions like the Japanese space agency’s (JAXA) Hayabusa2 probe demonstrates that an asteroid can have a very loose internal structure – similar to a pile of rubble – that is held together by gravitational interactions and small cohesive forces”, says study lead-author Sabina Raducan from the Institute of Physics and the National Centre of Competence in Research PlanetS at the University of Bern.
Yet, previous simulations of the DART mission impact mostly assumed a much more solid interior of its asteroid target Dimorphos.
“This could drastically change the outcome of the collision of DART and Dimorphos, which is scheduled to take place in the coming September”, Raducan points out.
Instead of leaving a relatively small crater on the 160-meter wide asteroid, DART’s impact at a speed of around 24’000 km/h could completely deform Dimorphos. The asteroid could also be deflected much more strongly and larger amounts of material could be ejected from the impact than the previous estimates predicted.
Reference: “Global-scale Reshaping and Resurfacing of Asteroids by Small-scale Impacts, with Applications to the DART and Hera Missions” by Sabina D. Raducan and Martin Jutzi, 1 June 2022, The Planetary Science Journal.
DOI: 10.3847/PSJ/ac67a7
(Score: 5, Insightful) by Runaway1956 on Tuesday August 09 2022, @02:34PM (1 child)
No one is going to know what happens, until we can identify the various types and sorts of asteroids with certainty, then hammer a few of them. If we aren't sure of the composition of any particular asteroid, we can't predict what will happen when we disturb, or try to disturb, the asteroid's trajectory. AFTER the impact of the DART, people can do some more meaningful studies.
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(Score: 2) by JoeMerchant on Tuesday August 09 2022, @05:32PM
I feel like the recent 'surface like a pit of plastic balls' finding is driving this observation, and you're exactly right: it DEPENDS. Some asteroids are going to fragment into myriad smaller objects, some might just split in half, and the occasional Psyche is going to ring like a bell and chug along with the net momentum like a classical physics 101 lesson.
First problem is spotting the incoming threat with sufficient time to do something about it. We've been making pretty good observations of NEOs for the past few decades, but I suspect the next big one that hits isn't going to be a NEO (for long).
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(Score: 2) by HiThere on Tuesday August 09 2022, @04:21PM
Lots of "could"s in that summary. I find it really hard to disagree with. OTOH, I'd expect that there's a lot of variation between different asteroids, so while those "could"s are correct, it's not a reasonable thing to count on. I'm sure that some asteroids are essentially aerogels, without the air. And that some aren't. And that some are a rocky or metallic core surrounded by what's left of an aerogel. And the only way you can sort of distinguish them from a distance is by their mass, if you can measure it. (See how much it causes something else to be deflected from it's orbit, but you need to know the mass of the "something else".)
Consider that many asteroids probably started out a a big ball of largely methane, with some other stuff, including a bunch of rocks. Then they got heated a bit in a vacuum, and the methane evaporated. But other asteroids built about the same structure around a large hunk of rock or metal.
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