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New asteroid strike images show impact 'a lot bigger than expected'
- db48x 4y agoAsteroids are apparently a lot softer and fluffier than we thought. More like gravel and sand clumped together rather than being giant boulders.
- samatman 4y agoMy understanding is that we've known for a long time that they range from a sooty snowball to a single chunk of pitted iron alloy. Looks like this one was a softie.
- db48x 4y agoThat’s true, but I’m thinking that every class of asteroid is going to go down a level or two on the scale once we actually go poke them. Look at Bennu: they expected from the estimated density that it was a conglomerate and would have a significant amount of surface sand and dust they could pick up. Close up pictures showed that it is a lot less homogeneous than they expected, with huge boulders right on the surface as well. That doesn’t match with the measured mass and density since boulders are heavy and dense, but maybe there are more internal voids. But then when they touched it, the nitrogen gas that was supposed to blow some dust and sand into the collection chamber also threw a huge amount of material out and away from the probe. It may even have shattered some of the gravel, meaning that stuff is really more like styrofoam. It may still be silicates, but it is probably foamy. Think of pumice rather than sandstone or granite. Those giant boulders might be more like stage props than actual boulders. It will be very interesting to see what that stuff looks like when they get the samples back. All those stories of hollowing out an asteroid and turning it into a habitat or generation ship for 50,000 people aren’t looking so prescient. :) Of course on the other hand it could turn out to just be selection bias: sample return missions are obviously going to pick a low–density asteroid that they hope will at least have some dust they can scoop up, instead of picking a really dense one that might turn out to be too difficult to collect from. Also, I’m ignoring the dwarf planets that happen to be in the asteroid belt, like Ceres. We can reasonably expect them to have some real rocks.
- yetihehe 4y ago> It may even have shattered some of the gravel, meaning that stuff is really more like styrofoam. [...] All those stories of hollowing out an asteroid and turning it into a habitat or generation ship for 50,000 people aren’t looking so prescient. :) Even simpler then, insert giant balloon in the middle, pump it up, cover walls with concerete and you have habitat, no expensive drilling and hollowing out.
- db48x 4y agoWhat would you gain in that situation? Just some radiation shielding. Most stories about hollowing out asteroids wanted to gain at least some structural rigidity, which in your scenario comes entirely from the concrete you have to ship into space. Ideally you would want to melt the asteroid and blow it up to kilometers across and/or spin it for artificial gravity. Heating and melting foam is harder than solid rock or metal, and spinning it is useless if it has no strength in tension.
- yetihehe 4y agoIn that case: blow up the balloon, melt rock outside balloon. You could make "cement" from grinding local material plus some binder, that way you bring in less mass. Radiation shielding is also a nice use for asteroid's mass. I'm just saying that blowing up a balloon is easier than extracting several cubic kilometers of rock from inside of asteroid. You can start from that premise and try to find some solutions. > Heating and melting foam is harder than solid rock or metal You can grind it, then blow it with very hot gas onto your baloon, making a nice melted coat of rocks. This technique is already used to repair metal rotor shafts, it deposits machinable metal: https://www.youtube.com/watch?v=NAeBpF84Q9M https://www.youtube.com/watch?v=NAeBpF84Q9M
- db48x 4y agoThat would be very fun, but also a lot of gas to ship up from Earth :)
- senectus1 4y agoSOME
- gl-prod 4y agoYeah, some asteroids don't have enough gravity to turn those gravel and sand into solid base.
- demarq 4y agoNot really, the impact was at 23000 kilometres per hour. The live coverage just made it look slow and small.
- helloworld11 4y agoWorth noting that those "soft and fluffy" clumps of gravel and sand still move at 18+km per second and even one the size of Dimorphos striking the earth would easily cause an explosion big enough to completely level even the largest city (think 30 to 50 megatons of explosive energy upon impact). Or for example a comet, -mostly just a sort of dirty snowball- a couple miles in diameter would cause a global climatic catastrophe and vaporize every living thing and standing structure within hundreds of miles of its impact location. Terrifying capabilities for such soft and fluffy, brittle things.
- avidphantasm 4y agoThis is a super cool mission involving collaboration with lots of other space missions to do something of practical and theoretical interest. Bravo!
- hypertele-Xii 4y agoSo it "looks good" but that's all we get for now. A dust plume. What they can't say yet, is if the asteroid's trajectory was effected, at all.
- wolfram74 4y agothe kinetic energy of the probe was 900 times that of the gravitational binding energy of the moonlet, there is a non-trivial chance that the main thing we'll learn from this mission is how these gravel piles are destroyed via impactors. An important process to solar system development.
- lamontcg 4y agoI think I worked it out that the kinetic energy is equivalent to around 2 tonnes of TNT, or of roughly a US Navy Atlanta class light cruiser doing 90 mph down the freeway.
- burnerburnito 4y agoGood unit of measurement, that last one.
- andrewflnr 4y ago> 900 times that of the gravitational binding energy of the moonlet Wait, seriously? Maybe I should have paid more attention to the relative scale of these things. That makes it sound like the most reasonable expected outcome is total obliteration.
- wolfram74 4y agoThe mission was approved in 2015, which means it was designed before then, we've learned a good chunk about how smaller asteroids bind together since then, the hyabusa 2 and osiris rex missions were both after 2019, so it wasn't wholely unreasonable that some other kind of internal binding mechanism might be at play besides the piddling role gravity plays at these scales.
- stevecalifornia 4y agoThis page shows like 15 copies of the same mildly NSFW ad. Surprised this is a thing on Spacedaily.
- beej71 4y agoThis is why I run Firefox on Android with uBO. It's a different world.
- cortesoft 4y agoWeird, the ads for me were very boring.
- Fatnino 4y agoYou need to browse more "interesting" sites. It will spice up your ads.
- ericbarrett 4y agoSometimes these slightly-NSFW ads are what you get when you're heavy on ad blockers and such, because they're buying out the lowest/cheapest ad tiers where there isn't much targeting data available.
- 2Gkashmiri 4y agoYeah, like the other guy said about Firefox android, I normally use Firefox focus and I saw "0 ads". Maybe it'd because of pihole but I suppose focus does a good job by itself. People need to forget using chrome on android at least
- adrianmonk 4y agoI'm not a scientist, etc., but isn't this potentially slightly bad news? The more stuff getting knocked free, the less momentum gets imparted to the asteroid itself, so the less its course is changed.
- Fatnino 4y agoNo, every bit of debris that flies off carries away some momentum.
- deleted 4y ago[deleted]
- BlueTemplar 4y agoI guess it's important because momentum is a vector, and the debris fly off in a direction on average opposite to where we anted to push it, so this also means that the momentum of the asteroid itself has been changed by (at least) that negative ? But why is this better than a perfectly inelastic impact without any debris ? Was a significant fraction of the asteroid blown away ?
- Fatnino 4y agoYou can apriximate the debris to rocket exhaust. There isn't an engine bell to direct it and make it all leave in the most efficient direction but it's still thrust.
- BlueTemplar 4y agoI know, my above statement wouldn't make sense without this assumption.
- adrianmonk 4y agoThat's my point, though. The goal is to knock the asteroid off course sideways. (Perpendicular to its direction of travel, so that it misses the Earth.) You slam something into it, and that changes the asteroid's momentum because total momentum is conserved in a collision. If the asteroid stays in one piece, then after impact, it will be going sideways at some particular velocity. If instead some pieces break off and speed off at a greater sideways velocity, then the parts that didn't break off have to be going at a smaller sideways velocity. In other words, if some debris breaks off, it carries away more than its "fair share" of momentum, and the remaining part gets less momentum.
- verisimi 4y ago> Astronomers rejoiced as NASA's Double Asteroid Redirection Test (DART) impactor slammed into its pyramid-sized, rugby ball-shaped target 11 million kilometres (6.8 million miles) from Earth on Monday night. > Hubble images from 22 minutes, five hours and eight hours after impact show the expanding spray of matter from where DART hit. > The Hera mission, which is scheduled to launch in October 2024 and arrive at the asteroid in 2026, had expected to survey a crater around 10 metres (33 feet) in diameter.
- rambambram 4y agoStop shooting sh!t at asteroids that are not heading for earth, please. You don't know upfront what's going to happen. What if the m0f0 splitted into two parts and one of the big parts was heading for earth now? Then what? Gonna play Armageddon, just as in the movies!? There are more people on earth than only Americans, okay. P.S. All jokes aside, all NASA people are probably very smart and sh!t, but please also think about all other people on earth. If you fvck up, you fvck up for everybody. Noblesse oblige. Space is pretty much unknown territory, be careful.
- TheCapeGreek 4y agoIf you're going to use coarse language, there's no point in censoring with ! and v.
- somat 4y ago"You don't know upfront what's going to happen" Yes, this is exactly why we are shooting shit at asteroids. So we do know what happens, so when that dark time comes and we need to shoot something at an asteroid to save a billion lives we know how to do it correctly.
- jl6 4y agoThe variability of composition of asteroids, from rubble piles to solid masses, makes me think that future asteroid diversion missions will look not so much like a big gun fired at the last minute, and more like a decades-long programme of search, analysis, and engineering tailored to each target.
- ulfw 4y agoyou don't always have decades though to predict an Asteroid impact event
- saiya-jin 4y agoWouldn't nuke going off just next to it nudge anything enough off course to not have to worry about composition? Or Hollywood yet again inserted a very unrealistic picture of how things work in my head. Or we strictly prefer not sending nukes up there outside WWIII scenario. But then plenty of satellites have/had nuclear fuel as main source of energy, just not critical mass for anything BAM, just nasty dispersion in the upper atmosphere threat.
- XorNot 4y agoA nuke going off "near" anything in space will do very little damage - there's no shockwave propagation, so all you have is the bombs heat - which at least half gets wasted on empty space. One of of the big problems with nuking asteroids is, as in this case, if it's a rubble pile then it can be considerably difficult to get enough physical contact with it to even meaningfully effect it. Hence the reason for DART: we've got an impressive something but the question is did we even successfully deflect the trajectory of the bulk of the material?
- ncmncm 4y agoA lot of smallish bolides could be much worse than one big one. Particularly if the big one would miss, but many of the saller ones don't.
- BatteryMountain 4y agoOr, just fling a giant tarp or net (depending on whether it seems solid or not) at it and pull it in a different direction instead of essentially firing a projectile at it.
- somat 4y agoWhen I was watching the show I was wondering why they did not put a second probe right behind the first to observe the impact. And when I went looking for more information about DART it turns out they did. the LICIACube. very cool. So now the question is why was this not mentioned in the nasa show(perhaps I missed it) and why have I not heard anything about LICIACube from anywhere else(perhaps I missed this as well). did LICIACube fail and every one is being quiet about it? https://en.wikipedia.org/wiki/Double_Asteroid_Redirection_Test https://en.wikipedia.org/wiki/Double_Asteroid_Redirection_Te...
- snakeboy 4y agoYou can find the images in a few different articles (though I wouldn't be surprised if science journalists failed to specify this), as well as on NASA's website [0]. [0] https://www.nasa.gov/feature/first-images-from-italian-space-agency-s-liciacube-satellite https://www.nasa.gov/feature/first-images-from-italian-space...
- techdragon 4y agoIt worked, it’s just a very small machine with an equivalently small transmitting antenna, so even with the big dishes of the deep space network it’s going to be a while before we get all the data back. We have some data already https://www.ssdc.asi.it/liciacube/ https://www.ssdc.asi.it/liciacube/ and more is on the way!
- mkl 4y agoIt worked, and it's mentioned in the article: "the 'really impressive' Webb and Hubble images were remarkably similar to those taken by the toaster-sized satellite LICIACube, which was just 50 kilometres from the asteroid after separating from the DART spacecraft a few weeks ago."
- biztos 4y ago> Astronomers rejoiced as NASA's Double Asteroid Redirection Test (DART) impactor slammed into its pyramid-sized, rugby ball-shaped target… Good thing it wasn’t torus-sized or they might have missed!
- saboot 4y agoI'm now wondering if a torus shaped space object is even possible ..
- techdragon 4y agoIf they’re not possible then we’re going to have a lot of problems when we try to build rotating space stations for artificial gravity! More seriously though, there is as always math for this. For an object to remain torus shaped it has to resist gravity trying to pull it into a more spherical shape around the centre of mass. More info here if your curious https://astronomy.stackexchange.com/q/2092/501 https://astronomy.stackexchange.com/q/2092/501
- c7b 4y agolots of planets have rings. it just depends on how you define space object...
- biztos 4y agoYes but what size is torus-sized? Is a torus bigger than a pyramid?
- hbossy 4y agoI bet they were all disappointed because if there were no significant effect the next logical step is to allow the team try again with nukes.
- marginalia_nu 4y agoNukes in space are actually not all that great. The same goes for explosions in general. A lot of our intuition for explosions come from how they interact with atmosphere, which will compress and expand, and mediate a shock wave in a way vacuum categorically does not. A nuke is essentially reduced to a flash of ionizing radiation and a few kilograms of gas rapidly cooling and diffusing into the vacuum of space.
- klysm 4y agoDo they need some mass to throw around? I wonder if you could like embed one in an asteroid.
- SketchySeaBeast 4y agoAlso, trying to get nukes into space is not that great both in terms of "what if something goes wrong" and the optics from foreign powers.
- dbbk 4y agoYeah nukes are not something I'd want to "fuck around and find out" with
- carlsborg 4y agoUnfortunately this technology is likely to be weaponized at some point in the future as radiation-free multi-megaton munition. The project name does tell us that the goal is to redirection not destruction of the asteroid.
- Etheryte 4y agoI think you might be overlooking the fact that it's simply a lot easier to redirect a big object than it is to completely destroy it. If the cheaper option does the job of keeping our planet safe, why would we try to go with an exponentially more expensive one?
- nebalee 4y agoThis munition is very rare, has to be aimed a very long time before it can hit anything and the whole process is very noticeable. I wouldn't lose any sleep about that.
- perihelions 4y agoCounterpoint: it would, reciprocally, take months to launch a military strike to disable a military asteroid base, so it offers robust second-strike capability. You can no longer launch a sneak attack on your enemy's strategic bases. The short timescale of nuclear war decision-making is chaotic, destabilizing, and has almost led to *accidental* apocalypse several times in the 20th century. Slow, deliberated deterrence could take uncertainty and accident out of the equation.
- perihelions 4y agohttps://sci-hub.se/https://doi.org/10.1038/368501a0 https://sci-hub.se/https://doi.org/10.1038/368501a0 ("Dangers of Asteroid Deflection" Carl Sagan & Steven Ostro) It's a good hypothesis that humanity developing asteroid deflection is more dangerous than not; that the optimal course is to do nothing. (Fortunately, kinetic impactors like this project are borderline useless/harmless anyway (other than as basic research). Sagan was writing from the more ambitious worldview of the 20th century; a world where, if an asteroid is a problem, you cut a straight line through the problem with nuclear weapons. That's a more hazardous toolset!)
- chiefalchemist 4y agoQuestions: are all asteroids relatively the same in composition, density, etc.?
- ncmncm 4y agoNo. Like asking if all animals are about like a dog. All animals need calories and B-12. Other details vary. Many animals have arranged to grow internal bacterial colonies for B-12. A very few get calories from sunlight.
- chiefalchemist 4y agoThanks. But the animal analogy was heavy-handed and unnecessary. The gist was, we've crashed into a single asteroid. There are zero conclusions we can draw from that sample size. So "a lot bigger" just means someone didn't consider the true range of possibilities.