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Asteroid lost 1M kilograms after collision with DART spacecraft
- amelius 4y agoFeels like we're back in the stone age.
- lanewinfield 4y agohonest question: if a golf cart sized spacecraft ejected 1M Kg out of this asteroid, if it had hypothetically hit the earth's atmosphere, would it have broken up easily?
- fwlr 4y agoIt’s likely that the gigagram of ejecta is in some sense the “easiest” 1M kgs to knock out. I doubt it’s boulders and loosely compacted gravel all the way down.
- aidenn0 4y agoPerhaps turning it into 43000 1M kg sized rocks? If even a few hit that seems still pretty "civilization ending" to nme.
- vkou 4y agoDepending on the impact velocity, it would be ~10-30 times the energy of the Tunguska meteor, or ~3-10 times the energy of the Tsar Bomba. Anyone within one or two hundred miles of the impact site would have an incredibly bad day, but it's not civilization-ending. The Chelyabinsk meteor, FYI, weighed ~12M KG.
- vkou 4y agoThe asteroid weighs ~4.310^9 KG. If the impact speed were ~30 km/s [1], breaking it up in the atmosphere through friction would create about... E = MV^2/2 = 3.87 10^18 joules. For contrast, the energy released by the Tsar bomba was 2.45 * 10^17 joules. The Tunguska meteor impact was something on the order of ~1 * 10^17 joules. Even if much of the energy dissipates in the upper atmosphere, and does so over multiple seconds, I'd say that anyone within ~150 miles of the point of 'impact' will likely have a very, very, very bad day. [1] Which is a pretty bad case. The Chelyabinsk meteor was traveling at ~18 km/s - a 30 km/s impact would be close to a 'head-on' collision.
- Symmetry 4y agoMaybe, maybe not. This was a sudden impulse to one point on the asteroid but reentry would be a gradually increasing force across the whole leading edge.
- leros 4y agoMissed opportunity to use the term megagram. Edit: I mean gigagram
- pkage 4y agoWouldn't that be a gigagram? Even more cool.
- dylan604 4y agohow ever you measure it, the street value of all that powder has got to be astronomical
- nordsieck 4y ago> Missed opportunity to use the term megagram. Did you mean gigagram?
- leros 4y agoTwo comments saying this. Doesn't mega mean 10^6 aka 1 million?
- SkyMarshal 4y agoTLDR: "[Dimorphos] ... seems to be a loose pile of rubble barely held together by gravity — whose surface would probably shatter spectacularly when DART hit it. DART [impacted] Dimorphos at more than 6 kilometres per second. The impact caused the asteroid’s orbit around another [larger] space rock [Didymos] to shrink — Dimorphos now completes an orbit 33 minutes faster than before the impact. The impact ejected at least one million kilograms of rock from Dimorphos’s 4.3-billion-kilogram mass. The debris formed a tail that stretched for tens of thousands of kilometres behind the asteroid. Various telescopes watched over weeks as the tail shifted and evolved under the pressure of the Sun’s rays; the Hubble Space Telescope even detected a second tail, which had disappeared by 18 days after the impact. One factor [in successfully changing Dimorphos's orbit] is that the spacecraft hit a spot around 25 metres from the asteroid’s centre, maximizing the force of its impact. Another is that large amounts of the asteroid’s rubble flew outwards from the impact. The recoil from this force pushed the asteroid further off its previous trajectory. Researchers estimate that this spray of rubble meant Dimorphos’ added momentum was almost four times that imparted by DART4." It's good that this technique worked on a "loose pile of rubble", but I'm not sure we can assume all asteroids are composed in the same way. A denser rock of iron or similar might be more difficult to divert.
- ericbarrett 4y agoNo, this was a successful test! Very small changes in the energy of an object can cause large changes in its trajectory. An impact at this same scale could be the difference between a direct collision with Earth, and not even getting inside the moon's orbit. We don't need any mass to be knocked off. In fact, it's probably even more effective if the target stays intact. What we do need is time. If the asteroid is weeks away, we've got a great chance of deflecting it. If it's hours, we'll certainly be struck.
- Tepix 4y agoWe need years, not weeks
- jessaustin 4y ago
- wonderwonder 4y agoGood article and very interesting content but stuff like: "The impact caused the asteroid’s orbit around another space rock to shrink — Dimorphos now completes an orbit 33 minutes faster than before the impact" drives me nuts. How long did the orbit originally take? Without this information it very much obscures the point. Edit: I looked it up "Before the impact, the orbital period was 11 hours, 55 minutes. It now is 11 hours, 22 minutes. NASA's previous estimate, announced in October, was an orbital change of 32 minutes. The benchmark for success had been set as a change of at least 1 minute, 13 seconds." So it reduced it by about 1%. Pretty cool. Edit2: as pointed out correctly by @statusgraph it's actually close to 5%. I fumbled the math on that. https://www.voanews.com/a/asteroid-bashing-spacecraft-phenomenally-successful-studies-find/6985731.html#:~:text=%22The%20momentum%20of%20the%20collision,to%20Didymos%2C%22%20Thomas%20said.&text=Before%20the%20impact%2C%20the%20orbital,was%2011%20hours%2C%2055%20minutes https://www.voanews.com/a/asteroid-bashing-spacecraft-phenom....
- m4rtink 4y agoYeah, that is a quite substantial change! I was kind of expecting something much smaller - eq. measurable but not really significant.
- dylan604 4y agoin astronomical terms, measurable but not really significant, can become significant at cosmological times scales/distances. adjust the trajectory of something at the distance of Jupiter by a "measurable but not really significant" amount, and it could be the difference of a direct impact with earth or a near miss by the time that not really significant amount is accumulated for that distance.
- statusgraph 4y agoBy almost 5% actually! https://www.google.com/search?q=11hr+22min+%2F+11hr+55min&oq=11hr+22min+%2F+11hr+55min&aqs=chrome..69i57j33i10i160l3.6536j0j1&sourceid=chrome&ie=UTF-8 https://www.google.com/search?q=11hr+22min+%2F+11hr+55min&oq...
- xwdv 4y agoSo will we be keeping projectiles ready to go at moments notice if we detect a killer Asteroid heading our way or what?
- dylan604 4y agoa cosmological moment's notice maybe
- ianburrell 4y agoThere isn’t much need for quick reaction time. This technique can only move asteroid by tiny bit so it only works over years. If the asteroid is going to hit sooner, there is not much we can do. Our rockets aren’t that fast and would take months or years to get there. It does make sense to develop spacecraft so it can be launched quickly without going through years of development. Maybe build two and test one out. Then we would be ready to build more if needed.
- AtlasBarfed 4y agoProject Orion is perfect for that mission.
- ianburrell 4y agoYou mean for the launch? Or getting to asteroid? Or moving the asteroid? Launching Project Orion from the ground would dump a ton of radioactive fallout. Unfortunately, it is expensive to launch with rockets because of the heavy plate and having to assemble it. Launching it from orbit will knock out most of the satellite and could cause EMP over wide area. It doesn't do any good if you deflect asteroid, and one this size would only cause regional damage, if destroy civilization. The Starship is big enough that can launch spacecraft with a few nukes and rocket to reach asteroid. Assuming that Starship is being launched regularly, then launching or building the spacecraft would be sufficient. This whole mission of colliding with asteroid was done because it is uncertain if nukes could be used to deflect asteroid. There is a danger that nuke would blow the asteroid apart instead of deflecting it. For one this size, that probably wouldn't be a problem but turning larger one into few smaller ones would be bad.
- neom 4y agoheh, if you send Double Asteroid Redirection Test into google it gives an easter egg unlike any I've seen before... it's cool, but weird.
- version_five 4y agoThanks for posting that, that was fun
- neom 4y agoApparently it's old news: https://www.creativebloq.com/news/google-dart-mission https://www.creativebloq.com/news/google-dart-mission - but it was new to me!
- tambourine_man 4y agoThat’s so cool, reminds me of the old, more fun, Google
- edrxty 4y agoGives me hard nostalgia for the old, more fun, internet
- neuronic 4y agoAh, I have waited a long and strenuous time for the inevitable day in which this thread becomes relevant once more: https://news.ycombinator.com/item?id=19038327 https://news.ycombinator.com/item?id=19038327
- deleted 4y ago[deleted]
- reidjs 4y agoFor other people who want to see https://www.google.com/search?q=Double+Asteroid+Redirection+Test https://www.google.com/search?q=Double+Asteroid+Redirection+...
- deleted 4y ago[deleted]
- jay_kyburz 4y agoI wonder if we checked to see if there were any little creatures living on Dimorphos before smashing it to bits.
- pugworthy 4y agoWell you know the answer to that question. Better for you to talk about why you asked that question.
- gl-prod 4y agoAll the planning charts and demolition orders have been on display at your local planning department in Alpha Centauri for 50 of your Dimorphos years, so you’ve had plenty of time to lodge any formal complaint and it’s far too late to start making a fuss about it now.
- andybak 4y agoSomething something Beware of the Leopard...
- Zamicol 4y agoThat headline is... horrible. What are SI units for if not for this?
- slaw 4y agoI wouldn't complain. At least it is not in football fields, yards, pounds or other American units.
- akira2501 4y agoI happen to agree, but the headline conveys information in the most accessible format. SI just makes a lot of promises that it can't deliver on, because human beings aren't interested in such a unit system. They seem to want just three unit scales, "smaller than me", "the same size as me", and "larger than me." They will fit the entirety of their experience and frame of reference into these three scales, even when they know there are other options. It's probably the reason they punted and let a _kilo_gram be a base unit in the first place, and why everyone represents the distance to the sun in kilometers instead of gigameters; even though they round the kilometer figure down to a point where gigameters would clearly be the most warranted.
- dylan604 4y agoEveryone was perfectly fine with "the size of 3 buses".
- screamingninja 4y ago> human beings aren't interested in such a unit system All of them??
- senectus1 4y agoso 610kg smashed into 5.5 million tons and it lost 1 million tons in ejected mass? I presume that if it wasn't such a loose collection the result would be quite different. Given that it is a loose collection it wouldn't be a real threat to earth anyway (if for instance it was heading towards us) because that would cause it breakup in the atmosphere easier. they seem to be surprised by these equations.. I thought this was all fairly established science.
- EGreg 4y agoNow that’s what I call weight loss!
- FartyMcFarter 4y agoIt's a good first step, but still some way to go! > The impact ejected at least one million kilograms of rock from Dimorphos’s 4.3-billion-kilogram mass.
- GolfPopper 4y agoHow soon can we start hitting Mars with diverted Kuiper belt objects?
- trompetenaccoun 4y agoShhh. That's only for when the Martian colony seeks independence. I promise there are currently no plans to attack Mars.
- h2odragon 4y ago> there are currently no plans to attack Mars. speak for yourself. The best way to deal with the inevitable Martian uprising is to eliminate Mars before it is ever colonized.
- BurningFrog 4y ago"1000 tons" in common language.
- shirro 4y ago1000 tonnes. Though using the base units is never wrong and I generally prefer it. In common language a ton can be a short ton (US) or long ton(UK) though I am sure they are all well within the margin of error.
- davidw 4y ago"Ask your doctor if the DART spacecraft weight loss program is right for you..."
- yborg 4y agoThere was a quote I read somewhere about giant impact extinctions to the effect that "They'll keep happening until a species evolves that can do something about it."
- Oxidation 4y ago> It is a truth universally acknowledged, that a single species in possession of a good technological base and a will to survive, must be in want of a interplanetary kinetic asteroid redirection system.
- kzrdude 4y agoThen there'll be that one stone that's too big, and we'll have to wait for a whole another species to come up and try again
- andybak 4y agoI'd love to know who "we" refers to in that sentence. ;-)
- kzrdude 4y agoThat's funny. It's either the guests at the restaurant at the end of the universe. Or just a universal peanut gallery that we all can imagine we belong to.
- deleted 4y ago[deleted]
- wongarsu 4y agoAnd that's why some people want a self sufficient Mars colony: so evolution doesn't have to start with small mammals again when that happens.
- jeremyjh 4y agoIt would be waaaay easier to build a self sufficient colony hundreds of feet below the ice in Antartica. And there would actually be a reason to want to survive.
- deleted 4y ago[deleted]
- ggm 4y agonobody yet has said 1m KG == 1000 1000kgs == 1000 tonnes == 1 kilotonne. the original A bomb was 17 kilotonnes. explosive equivalent. I have no idea what a kilotonne of friable matter entering the atmosphere represents, in explosive equivalent.
- yread 4y ago1 kilotonne moving at 20 km/s is about 2e14 J or 50 kt TNT equivalent. So, quite a bit more!
- beebeepka 4y ago1M kilograms... If anything, these few days have shown to me that many on HN don't seem to get the metric system at all. Broken math and silly conversions everywhere, baby Just this week we had the highest rated comment present completely incorrect kg to ton conversion: https://news.ycombinator.com/item?id=34955578 https://news.ycombinator.com/item?id=34955578
- chungy 4y ago"ton" is overloaded with three units having the same name, although at least the "metric ton" is often spelled tonne (1 tonne = 1000 kg ≈ 2204 lbs), but that still doesn't do enough to disambiguate it in speech. In written texts, it can be difficult to impossible to know whether "ton" refers to the American unit (2000 lbs ≈ 907 kg) or the British unit (2240 lbs ≈ 1016 kg).
- beebeepka 4y agoI've never seen non-americans take ton for anything other than 1000 kg. The real funny thing in that other thread is the guy specifically claimed "metric tons" while doing math with some other type of tons. Who cares, though, right? What's important is sounding right
- Temporary_31337 4y ago1M kilograms so 1 gigagram or 1000 tonnes or about ten whales.
- chmod775 4y agoThanks. I got a couple whales of undetermined species in my aquarium and handle them daily to give them a good scrubbing. That comparison gave me some perspective.
- 867-5309 4y agothat subterranean aquarium under the football pitch?
- hef19898 4y agoHow many busses???
- janlaureys 4y agoAbout 146 assuming a bus weighs about 3.5 giraffes.
- tirpen 4y agoA bus typically weights around 20-40 tonnes depending on the model. So 25-50 busses.
- willyt 4y ago~7.5 tonnes for a bus that seats ~70 people, no? https://en.wikipedia.org/wiki/AEC_Routemaster https://en.wikipedia.org/wiki/AEC_Routemaster
- lm28469 4y agoAbout 3 football fields
- 4y ago
- tromp 4y agoDoes anyone know the impact angle? I.e. the angle between the trajectories of DART and Dimorphos prior to impact? I expect that a 90 degree angle would maximize the effect but would also make it hardest to hit the target.
- pas 4y agohttps://en.wikipedia.org/wiki/Double_Asteroid_Redirection_Test#/media/File:Dart-poster3.jpg https://en.wikipedia.org/wiki/Double_Asteroid_Redirection_Te... They hit it "head on" ... or you mean the actual angle? > Other work Ernst and her colleagues are doing recreates the impact itself. They calculated that the spacecraft flew in on a trajectory about 73 degrees above the local surface. "So not quite vertical, but pretty close," she said. https://www.space.com/dart-asteroid-smash-mission-impact-details https://www.space.com/dart-asteroid-smash-mission-impact-det...
- otikik 4y agoAfter Christmas, I might need to collide with a DART spacecraft as well.
- andylynch 4y agoNow Inners can sleep easy. But plenty more rocks in the belt you can’t see.
- andruby 4y agoI chuckled. I like the reference to The Expanse, but I'm not sure if this belongs on HN or rather on reddit
- andylynch 4y agoI kid but not really. The Expanse might be fictional but the threat it raises and considered with here isn’t - it’s good to see this as a proof of concept but there lots more to be done, detection included.
- xxs 4y agoThe Expanse had its own rather large article: https://news.ycombinator.com/item?id=26014455 https://news.ycombinator.com/item?id=26014455 top of the page
- Steltek 4y agoOh wow, it started as a game concept! I was just thinking I wish they made a videogame with the physics and geopolitics (stellar politics?) from the show.
- qohen 4y agoThere is an Expanse board game[0] that might interest you (it's been described as being like the cold-war themed classic, Twilight Struggle, but for up to 4 (TS only plays 2): The Expanse, a board game based on the Syfy television series of the same name, focuses on politics, conquest and intrigue similar to the board game Twilight Struggle, although with a shorter playing time. The card-driven game uses key images from the show, along with action points and events that allow players to move and place "Fleets" and "Influence". In more detail, players represent Earth's UN forces, the military of Mars, the rebels of the O.P.A., and the mysterious corporation Protogen Inc. Each player has special abilities that must be maneuvered to gain advantage. Players increase their control over the solar system using characters and events from the universe of The Expanse. (There's also expansion, The Expanse: Doors and Corners, that adds new tech, leaders, the protomolecule, etc.) The only problem would be finding a reasonably-priced copy as it appears to be out-of-print, which can lead to the price of second-hand copies going way up. [0] https://boardgamegeek.com/boardgame/220792/expanse-board-game https://boardgamegeek.com/boardgame/220792/expanse-board-gam...
- mabbo 4y agoAt some point in the next few decades, I expect to see humanity use this technology to divert an asteroid away from the Earth. And that's pretty neat. Chelyabinsk was only a 20m asteroid, yet thousands were injured and a lot of damage was done. It's not inconceivable that in the next couple decades, we could predict that sort of event years out, and send a (likely much smaller) redirector mission to give it a tiny push, preventing the asteroid from entering Earth's atmosphere. What scares and fascinates me though is what happens when we start asking 'okay, but where is it going to hit, and how many of my voters live there?'
- saiya-jin 4y agoI actually expect them to route them towards Earth, to some stable orbit, to be mined. But yes first the collision protection, that's much simpler to achieve and important
- feoren 4y agoAn asteroid already on a collision course with Earth only needs a tiny push to miss if we hit it early enough -- think about slightly bumping a sniper before he takes the shot. An asteroid a month out, heading straight for Earth's center, could be redirected to just skim the outer atmosphere with only about 4 m/s of delta-V. On the other hand, getting a near-miss asteroid to orbit Earth instead means taking it from above escape velocity (11.2 km/s) to an orbital velocity, which means at least a thousand times more delta-V (more like 4 km/s). And that's the easy case -- getting an asteroid from the belt to fall toward Earth is another several km/s on top of that. Besides, ejecting 1M kilograms into a busy Earth orbit in order to slow the asteroid down sounds like a pretty scary idea. Especially since we'd have to do it hundreds of times for one asteroid. So no, it wouldn't be the same technology at all.
- vkou 4y agoThe problem is that we have no ability to conclusively determine whether or not an asteroid is on a near-collision course, or on an actually-collision course. And if it's the former, giving it a small bump is just as likely to put it on an actually-collision course as not doing anything at all.
- dom96 4y agoCan't wait until year 10000 when some alien planet invades Earth because DART happened to redirect this asteroid straight at them by accident. That would be a fun sci-fi story.
- empyrrhicist 4y ago... you realize that we just bumped a smaller object orbiting a larger asteroid so that it has a VERY slightly altered orbit, right? It's not like we drastically changed the orbit (let alone gave it escape velocity from the solar system).
- dom96 4y agoEver heard of the butterfly effect?
- voytec 4y ago> DART, which was the size of a golf cart, collided with a Great Pyramid-sized asteroid Ah, the wonders of the imperial system ;-)
- isk517 4y agoThe imperial system is perfect. 625,000 golf carts is one Great Pyramid, and 6,557,075 Great Pyramids of Giza is one Texas. How is this not obvious? /s Also, ChatGPT trivializes sarcastic responses that involve a bit of math.
- tonis2 4y agoUse this one trick, to lose 1M kg very quckly
- dghughes 4y agoI wonder if an antimatter collector could be built in space. Collect antimatter in a magnetic bottle and put that in a missile. Launch small, fast, powerful antimatter missiles via maglev towards asteroids. A triangular spaceship is not necessary.
- ianburrell 4y agoAntimatter is a really inefficient energy storage mechanism. Even if we figured out way to make it efficiently, it would still be super expensive. Nuclear weapons are efficient, they make energy, and comparatively cheap. Also, this mission was to demonstrate could move asteroid without large explosion. There is fear that most asteroid are loose rubble and would be blown apart by blast.
- Aissen 4y agoShower thoughts this morning while listening to the NEOMIR project that watches out for asteroids heading towards earth from one of its Lagrange points[1]: observing is the first step, but why don't we ready a few missiles waiting in space/orbit in case asteroids head towards earth ? How hard would that be to maintain in working condition for decades ? The goal would be to remove the need to prepare a rocket from earth (lots of fuel wasted, etc.) and have lower response times in case a "big one" (or many smaller ones) are ever detected. [1]: https://www.esa.int/Space_Safety/Planetary_Defence/NEOMIR_finding_risky_asteroids_outshone_by_Sun https://www.esa.int/Space_Safety/Planetary_Defence/NEOMIR_fi...
- zacharycohn 4y agoI think other countries would get pretty grumpy if any country publicly announced they were putting very very powerful missiles into orbit.
- JohnFen 4y agoI'm a little disappointed that the title didn't take the opportunity to use the term "gigagram".
- smm11 4y agoEarth's asteroid shield is all the orbiting stuff we have up there. Musk may save us all after all.
- dragonwriter 4y ago> Earth's asteroid shield is all the orbiting stuff we have up there. That’s not even an asteroid speedbump.
- 3836293648 4y agoWhy do we just give up on metric prefixes when it comes to mass? It's a gigagram, not a milion kilos
- robertlagrant 4y agoThat's a great alternative to kiloton.
- frob 4y agoAt least it wasn't 1 megakilogram
- kolinko 4y agoit could've been 1 kilomegagrams
- horsawlarway 4y agoWell... at least to me, one of those is a large amount of a mass that I have some understanding of. The other is lalaland non-sense. I'd have even preferred "Billion grams" over gigagram. Although a gram is really hard to intuit about, since it's basically just too small. I can probably reliably tell you if an object I pick up weighs 1kg or 2kg, I probably can't reliably tell you if it weighs 1g or 2g.
- tabtab 4y agoWe all need to diet when we get up there in years.
- knodi123 4y agoWhat's the point of the metric system if we have to say one million thousand grams? Just say "lost one gigagram"!
- kats 4y ago$330 million dollars just for that, it's an insane waste of money. The Mars helicopter cost $80 million dollars. 50% off the US doesn't have 1k in their savings account.