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NASA's DART spacecraft changed an asteroid's orbit around the sun
- fay_ 8mo ago[dead]
- p0w3n3d 8mo agoWow, that's the first step! However, the most efficient method would be actually land (I know - maybe even impossible?) on it, and use propellers to change its trajectory. We don't have too much throwaway high-tech to crash it on asteroids...
- Incipient 8mo agoI'm not sure this is actually a necessary explanation...but while propellers technically COULD function in space (not a perfect vacuum, right?)...they're basically going to be useless.
- Rexxar 8mo agoHe probably misuses "propeller" which is strangely restrictive to "rotative blade propulsion" in English whereas "to propel" is generic in its meaning.
- fc417fc802 8mo agoBe careful about how you store those inflammable propellers.
- birdsongs 8mo agoInflammable made me so angry as a child/teen when I found out. I read it in our encyclopedia set but we didn't have a dictionary, and this was pre-internet. It was in the context of hydrogen and I could have sworn it was flammable. But here is this encyclopedia telling me it's INflammable. It's... not flammable? Looked it up in the school library. Thank you, that memory came up from the depths of time. Probably haven't thought about that in 30 years. Funny how we sometimes just didn't know stuff, and couldn't find out back then.
- Daneel_ 8mo agoExactly! The only logical way out of the flammable/inflammable mess is to use 'flammable' and 'non-inflammable', which makes me so mad.
- Rexxar 7mo agoIt's just a parsing error. "in-" is also a prefix to create verbs from a name or another verb like inhume, inflame, induce, incite, inject, infiltrate. Inflammable is (inflame)-able and not in-(flammable)
- Daneel_ 7mo agoI agree, but it’s ambiguous, hence the problem. There are many counter-examples to your examples, such as “direct” and “indirect”, “humane” and “inhumane”. The words used should be clear in their meaning. “Inflammable” is ambiguous, and it makes a great deal of difference which meaning is intended. Flammable is unambiguous, as is non-inflammable. I’m forced to use these. Personally, I’m more in favour of flammable (able to catch fire) and inflammable (not able to catch fire).
- fc417fc802 7mo agoThere's an inconsistency but no ambiguity, only ignorance. Inflammable only ever means one thing regardless of how ridiculous english might be. The historically correct term would be non-inflammable. The modern variant is non-flammable. Similarly, inflammable is the historic term and flammable is the modern variant. The confusion arises when people are exposed to the word flammable and then attempt to apply the usual rules to construct a word they've never actually used before. This isn't the usual sort of inconsistency introduced by our fusing multiple incompatible languages. It's from the original Latin and I'm unclear what led to it. For example consider inflammable versus inhumane. It seems Latin itself used the prefix to mean different things - here on(fire) versus not(human). But confusingly it's ex to indicate location, despite ex also being the antonym of in. So ex equo means you are on horseback, not off it as I would have guessed.
- p0w3n3d 7mo agoYep. Thanks. Non native speaker here. I thought more of a booster? Something that would mix hydrogen and oxygen to create thrust. Thruster maybe?
- XYen0n 8mo agoImpact is actually a more efficient method, as it avoids the fuel consumption required for deceleration and soft landings.
- prism56 8mo agoInteresting. I'd not considered the loss of mass as a means of propulsion. Obviously there was the kinetic energy transfer but the impact ejacted some of the asteroids mass opposite to it's trajectory further increasing it's trajectory change. Cool demonstration, hopefully not needed one day.
- messe 8mo agoThat's how rockets work.
- prism56 8mo agoYeah, I sort of meant in the context of an object losing its mass, it's seldom used on earth as the effects are small but on the timescale/distance/speeds of an asteroid it could have noticeable effects. Rockets are using mass loss but there's more going on with the rapidly expanding gas causing the increased impulse.
- fc417fc802 8mo agoRockets are able to optimize due to dealing with a gas. It's still just pushing off of a disconnected mass. You go one way the lost mass goes the other. If you think about it that's how a cannon works. The projectile gets pushed forwards and the barrel gets pushed in the opposite direction. Some of the larger ones can push their launcher back quite a bit more than you might expect. My point is that this is actually a common failure of intuition. We tend to think of larger objects on earth as fixed and in our day to day life on dry land they often are (at least more or less) due to static friction. A slightly more interesting observation (I think) is that if the bodies don't achieve escape velocity relative to one another then the forces all cancel out in the end. It just might take an arbitrarily long time in the case of similarly sized masses.
- alhirzel 8mo agoIt's the butterfly effect. After the momentum exchange (the rocket slamming, stuff being ejected in the impact, etc), the entire system was left with different properties. From now on, the equation F=Gm1m2/r^2 will have a different m1, and you can sum the equation over all m2 (literally every other massive object in the universe).
- yubainu 8mo ago[flagged]
- willis936 8mo ago>it's more realistic than sending oil drilling experts to an asteroid Mandatory sharing of Ben Afleck commentary speaking for all of us. https://youtu.be/-ahtp0sjA5U https://youtu.be/-ahtp0sjA5U
- danparsonson 8mo ago> ...I wonder how much kinetic energy it had... Since kinetic energy is proportional to v squared, that highly depends on how you measure v...
- wartywhoa23 8mo agoWell done, DART, which country did you aim it to?
- zeusdclxvi 8mo agoIndia
- hulitu 8mo ago[flagged]
- NooneAtAll3 8mo agoI'm annoyed at these nothing-burger titles... Instead of pointing out that exact measurements finally came in (of long term movement change), journalist instead focused on the obvious outcome that everyone expects and knows
- ceejayoz 8mo agoThe top comment in this thread calls this "wild" and expresses amazement that this is possible; clearly it's not what "everyone expects and knows". The nitty-gritty details are what the article is for, not the title.
- gatreddi 8mo agoWild that we went from "can we even deflect an asteroid" to measurably changing a solar orbit. 150 milliseconds sounds tiny until you realize compounding over decades makes that a meaningful trajectory shift. The engineering confidence this gives for actual planetary defense is massive.
- jl6 8mo agoOr offense.
- ge96 8mo agoqueue the neurodivergent mech pilot
- wongarsu 8mo agoYou know what they say: the best planetary offense is a good asteroid redirect program It's also the best planetary terrorism, going by the plot of The Expanse
- redman25 8mo agoFirst things first, we have to colonize the rest of the solar system before we can terrorize Earth.
- dylan604 8mo agoThat totally depends on the type of super villain organization we're discussing. Some are willing to watch the Earth burn making the colonization step unnecessary. Others think humans are the problem and again would be willing to skip that step.
- vova_hn2 8mo agoIt depends on the size of the asteroid and precision with which it can be aimed...
- Ajakks 7mo ago
- Thanakorn_551 8mo agoThat's amazing
- esafak 8mo agoIs debris a problem? I think the ideal would be to embed or clamp a rocket on the target.
- ceejayoz 8mo agohttps://en.wikipedia.org/wiki/Mass_driver https://en.wikipedia.org/wiki/Mass_driver You build a little factory and use chunks of the asteroid itself as thrust.
- wongarsu 8mo agoA lot of asteroids are much less solid than we used to think. Some of them are big rocks, but many of them are just piles of sand- and gravel-sized material loosely held together by gravity. Clamps work great on the solid rock type, but many of the alternative methods - including smashing into it - work on asteroids of any composition That's valuable not only for versatility, but also because it would really suck to send a spacecraft on a redirect mission only to find out that our assumptions about the asteroid's composition were wrong
- dylan604 8mo agoSome have suggested attaching a solar shield to objects to add drag to alter the course. However, that would require a much more precise landing and some sort of drilling/anchoring effort. A kinetic impact like this is always going to be more efficient.
- hsnewman 8mo agoIs this a surprise?
- infinitewars 8mo ago> slowed the orbit of a pair of asteroids around the sun by more than 10 micrometers per second Or in other words, 1 meter per day Why not say that?
- stronglikedan 8mo ago1.22337962962963e-21 light years per second!
- mikeyouse 8mo agoBecause the SI unit is meters per second, so maintaining the “second” gives people with that understanding a basis in which to compare the delta-V.
- cheschire 7mo agoOne would think that any nerds that knowledgeable could divide by 86400 to make the article more accessible for the rest of us though.
- rkagerer 7mo agoI'm genuinely curious whether there are a substantial number of people out there who deal on a regular basis with dV's on such a minute scale. Who would that be, outside an asteriod-redirect program such as this? Satellite operators doing precision trajectory correction? I found the meter per day conversion helpful. Through another lens, it's about 0.000036 km/hour (or about 1.5 inches per hour).
- jjk166 7mo agoOkay but they didn't give it in meters per second, they gave it in micrometers per second. Converting to micrometers per second is exactly as much arithmetic as converting to meters per day.
- Tuna-Fish 7mo agoNo, it is not. It is in fact no arithmetic at all, if you understand how SI works.
- peder 7mo agoSaddened to load this comment thread and see no comments related to Mars and terraforming
- tianrking 7mo ago[flagged]
- drivebyhooting 7mo agoWhat is the feasibility of changing asteroid orbits to impact a specific location on earth? What is the circular error probable with current technology?
- Jeffrin-dev 7mo ago[flagged]