Comments
questioillustro t1_jaieyi2 wrote
you're still going to see this one: WE SHOULD BE USING THAT MONEY FOR REAL PROBLEMS!
could_use_a_snack t1_jaim24d wrote
My answer to this is always along these lines.
If you think the money spent on this mission (experiment, etc.) Should be spent on real problems, you as an individual, should lead by example. Do you like professional sports? All the money paid to pro athletes should be used for real problems.
Do you enjoy a morning cup of coffee? This is a 10+Billion dollar industry. All that money should be used for real problems.
How much do you spend on alcohol? How about your lawn? I could go on.
If you aren't willing to give up these basically useless things, why should I be willing to give up on the advancement of science.
Which in the end is why you don't live in a cave, or die of an infected toenail, and have a 60 inch TV that you can watch basketball on. (Which is basically grown men playing keep away in their underwear)
ferrettt55 t1_jaiutr3 wrote
It's the idea that we're sending piles of money into space or something. That money is being paid to the people that work on the program, who then put that money back into the economy.
bgplsa t1_jaj46tz wrote
THIS !!! ^ ^ ^ government and academic employees who spend money exactly like private employees on food, housing, entertainment, etc aren’t burning that money for heat, it hasn’t gone anywhere except to support people trogs don’t like.
[deleted] t1_jakga90 wrote
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TsQuad46 t1_jakzw2h wrote
Two different budgets, but go off I guess.🙄
[deleted] t1_jan9mxx wrote
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KiwasiGames t1_jal913t wrote
What is a space program other than a far future military research division? This research will eventually filter back to military applications and maintains the US hemomgeny.
[deleted] t1_jaky1in wrote
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gobblox38 t1_jakyhvu wrote
Also, the technologies developed from space programs go on to be used in society. It could be a mundane as velcro or as advanced as medical imaging technology.
Omfgsomanynamestaken t1_jaj8zi5 wrote
I mean if an asteroid isn't redirected from its collision course with earth... there won't be any real problems anymore. So there's that reason too!
f_d t1_jakxr4b wrote
Only if it is a big enough impact. Otherwise it will create lots and lots of other problems for everyone still alive.
GraveSlayer726 t1_jandr01 wrote
not if you stand directly at the impact site before it lands!
Impossible-Error166 t1_jaj9f7d wrote
I think finding out if we can redirect is a real problem.
Its also amusing that people think this is a waste of money, its like saying we should not invest in a military when you have Russia next to you.
monster2018 t1_jak2bf9 wrote
Also you can list the many dozens of technologies that wouldn’t exist without space exploration that do address everyday problems on earth. You can look it up and it’s mind blowing how many different on earth technologies originate from solving challenges for space.
TiredOfRatRacing t1_jajpdpd wrote
Jim Jeffries does a good bit on average people slowing down scientific progress. Setup is theist vs atheist, but i thought it was funny.
[deleted] t1_jakn5lj wrote
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FnB8kd t1_jalk6f6 wrote
I think a lot like you... and now I'm hungry.
[deleted] t1_janpyjq wrote
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PersistentHero t1_jak53su wrote
I didn't read it all but caffeine addiction is a real problem
Sad-Association-2742 t1_jak7zj1 wrote
I drink my problems away so thats money well spent, how about that smarty boy. /s
Erisian23 t1_jaixick wrote
Those are all real problems, I'm Bored, Tired, stressed, and the ground the ugly unmaintained lawn makes my depression so much worse I don't know if I can hang on much longer.
Those things affect me daily, immediately. This stupid potential once in a hundred million years chance we get hit by a rock from space isn't a now problem so stop using Now money on it.
CptHammer_ t1_jajvfc9 wrote
>Do you like professional sports?
Nope
>All the money paid to pro athletes should be used for real problems.
Agreed
>Do you enjoy a morning cup of coffee?
Nope
>All that money should be used for real problems.
Some of that money is already solving real problems.
>How much do you spend on alcohol? How about your lawn? I could go on.
Zero, zero, please do.
>If you aren't willing to give up these basically useless things, why should I be willing to give up on the advancement of science.
Done, now put your money where your mouth is.
Or answer this question: what's the best case scenario you can imagine that this research will help Earth?
From where I sit this planet has survived far worse than an asteroid impact. Any argument for continuing to waste money deflecting astroids is akin to watching drug dealers pimping their ride and saying to yourself, "welp, they could be out there selling drugs instead of investing in a clean hobby." Of course, neither is productive unless you're the car parts salesman.
wegqg t1_jajysp7 wrote
You're such an edgelord, maybe you should start spending some money on alcohol
AlexDKZ t1_jak3rjd wrote
>From where I sit this planet has survived far worse than an asteroid impact.
An asterod impact caused one out of the five major extinction events in earth's history, and are suspected in other three. I'd say, they rank pretty damn high in the "what could go wrong" scale.
CptHammer_ t1_jakrx43 wrote
So you say we survived 5, but a sixth is just crazy?
I think an asteroid is a natural course of nature and no amount of human involvement will overcome anything nature has to throw at us.
That being said, how is allowing people to die today of today's problems with these misspent funds going to save those same people in the future should an extremely unlikely event like an asteroid that we happen to detect in time to divert?
gobblox38 t1_jakzpx1 wrote
>So you say we survived 5, but a sixth is just crazy?
We (humans) weren't around for those 5 mass extinctions. The 6th mass extinction will very likely take us with it. The entire planetary ecosystem changes during/ after a mass extinction event.
>That being said, how is allowing people to die today of today's problems with these misspent funds going to save those same people in the future...
You've never heard of spinoff technology? People have said the exact same thing you have about space exploration since the start. The technologies developed for the space industry has been applied to other industries which includes the medical field. Tomorrow's medical problems are solved with today's space challenges.
CptHammer_ t1_jal71s5 wrote
>We (humans) weren't around for those 5 mass extinctions.
So what.
>The 6th mass extinction will very likely take us with it.
Doubt it. Humans will be the cause of human extinction. At that rate it's not an extinction it's darwinism. Spending money on diverting astroids is proof of what I'm saying.
>spinoff technology
I've heard of this. Perhaps you've heard of every kind of government funding into research ever is for weaponizing the stated goal. We wouldn't have nuclear bombs if it wasn't for the benevolent purpose of finding clean energy.
This goes for any significant government funding into research. Its true purpose is war, under the lie of something more benign.
gobblox38 t1_jal95lh wrote
>>We (humans) weren't around for those 5 mass extinctions.
>So what.
You really don't understand the significance here.
>>The 6th mass extinction will very likely take us with it.
>Doubt it. Humans will be the cause of human extinction. At that rate it's not an extinction it's darwinism. Spending money on diverting astroids is proof of what I'm saying.
We're the apex predator on this planet. If the ecosystem collapses, it'll take us with it. And yes, humans are the main cause of the current mass extinction event.
And no, spending money on research to deflect asteroids does not prove what you're saying.
>Perhaps you've heard of every kind of government funding into research ever is for weaponizing the stated goal.
Yeah, like how the smallpox vaccine program was really about weaponization. /s
>We wouldn't have nuclear bombs if it wasn't for the benevolent purpose of finding clean energy.
You are completely wrong. Nuclear programs came out of advancements in physics. Quantum mechanics showed that there was enormous energy potential locked away in atoms. Splitting these atoms in a controlled reaction would release energy. It was WW2 and the possibility of other belligerent nations building the atomic bomb that spurred American research. It had nothing to do with finding clean energy.
>This goes for any significant government funding into research. Its true purpose is war, under the lie of something more benign.
Sure, a lot space technologies can have military applications. So what? The ability to image the surface of a planet can have military applications, should we have never invested into that even though the same technology is used to find tumors in a living person?
I'm not really seeing the point of your position.
CptHammer_ t1_jalwsjc wrote
>And yes, humans are the main cause of the current mass extinction event.
Glad we can agree. So instead of stopping that we keep that moving forward by sending resources to space.
>Yeah, like how the smallpox vaccine program was really about weaponization. /s
You don't know that it wasn't government funded research? Seriously? You put /s as if you think the opposite of what you wrote. Which means you think the government decided to fund medical advancements back in late 1700s. They didn't, specifically England didn't.
Governments have however funded the weaponizing of vaccine technology with little success.
>You are completely wrong.
Then you go on to explain how I'm completely correct... I'm confused. The government poured money into nuclear energy only to weaponize it. Your explanation is out of fear that someone would weaponize it.
Fear realized!
But we'll never do anything like that again, right? We're interested in controlling astroids for good not evil, but if one other person says it could be used for evil you think we'll definitely not repeat an endless cycle of history. I'm sceptical.
>Sure, a lot space technologies can have military applications. So what?
You support war funding. That's all, not peace funding. You should just be honest with yourself. You're about self preservation and "protecting the planet" is incidental if it happens. It's the least important thing to you, but at least it's on the list.
wappleby t1_jal8s1v wrote
Wait you think we developed nuclear bombs for the purpose of finding clean energy? WHEEZE
CptHammer_ t1_jaluydz wrote
If you don't, that means you literally didn't pay attention to history and are excited to repeat it.
wappleby t1_jamac6d wrote
Ah yes please explain how the Manhatten Project was originally about producing clean energy
CptHammer_ t1_jamyovq wrote
1932 a decade before a government got involved
https://en.m.wikipedia.org/wiki/History_of_nuclear_power
1942 a government seeks to weaponize a new technology
https://en.m.wikipedia.org/wiki/Manhattan_Project
You're welcome
wappleby t1_jan4k0q wrote
Holy shit you link Wikipedia articles and then don't even read them. They weren't trying to develop clean energy. That was never the purpose of Fermi's research. Please do explain how weak interaction (Fermi's interaction) was the study of clean energy.
Rutherford's research was never for the purpose of clean energy either.
CptHammer_ t1_jaot0do wrote
>That was never the purpose of Fermi's research.
I never said it was.
>Please do explain how weak interaction (Fermi's interaction) was the study of clean energy.
It was the study of its potential use, who said he first that thought of use as an energy source?
Forget that question, how was it research to make a bomb specifically?
In fact so many people were talking about it as a use for an energy source that it seemed like a universal inevitable conclusion to Fermi's findings and therefore it would likely be impossible to point at who said clean energy first.
Should I point out that your favorite weapon making project first produced an energy reactor? Probably not because you don't think clean energy was the focus of the discovery before the government tried to weaponize it. In fact many at the time were saying that an energy reactor could cause it to be an accidental bomb which is what peeked the war machine's interest into turning it into an on purpose bomb.
wappleby t1_jap5q7h wrote
In what world was Fermi's research into weak interaction based upon it's use??
>In fact so many people were talking about it as a use for an energy source that it seemed like a universal inevitable conclusion to Fermi's findings and therefore it would likely be impossible to point at who said clean energy first.
Name a single physicist at that time that was talking about it as a inevitable fact that it would be an energy source. Again proving you don't even read the links you post as both Einstein and Bohr didn't even think it was possible to utilize the atom practically for quite a long time.
>Should I point out that your favorite weapon making project first produced an energy reactor? Probably not because you don't think clean energy was the focus of the discovery before the government tried to weaponize it. In fact many at the time were saying that an energy reactor could cause it to be an accidental bomb which is what peeked the war machine's interest into turning it into an on purpose bomb.
Holy shit your blatant ignorance to the Manhatten Project is astounding. The prospect of an atomic weapon was literally why the Manhattan Project was started. Have you ever even read the Einstein-Szilard letter?
And in regards to the nuclear reactor it was one of 5 options to make fissile material. It was never considered an "accidental bomb" its entire purpose was to produce plutonium. How do you confidently say so many blatantly false things?
CptHammer_ t1_japi7wl wrote
>Holy shit your blatant ignorance to the Manhatten Project is astounding.
Back at you. You really think they didn't prototype an energy reactor?
>It was never considered an "accidental bomb" its entire purpose was to produce plutonium.
Wrong it used very expensive natural uranium. About 5 tons with an additional 40+ tons of uranium oxide and several truckloads of graphite. I honestly can't remember those exact details but the reactor was created prior to the bomb because it was inevitable and to test the theory that a reaction wouldn't run away indefinitely. The reactor created by the Manhattan project ran for about a year before being moved and rebuilt and then ran for another decade.
I'm sure a super fan of government war craft can probably look up the specifics.
>Name a single physicist at that time that was talking about it as a inevitable fact that it would be an energy source.
Here's a nobody that applied for a patent in 1936, you clearly don't know him LEO SZILARD. I didn't have to look up his name, I didn't have to look up the timing of the patent and as I suspected it was a couple years before the Manhattan project started.
This reactor patent did come to him in a dream. It was theoretical for at least a decade with much input from the physical chemistry community as a whole.
https://worldwide.espacenet.com/publicationDetails/biblio?CC=GB&NR=630726&KC=&FT=E&locale=en_EP
wappleby t1_japkw4r wrote
>Wrong it used very expensive natural uranium. About 5 tons with an additional 40+ tons of uranium oxide and several truckloads of graphite. I honestly can't remember those exact details but the reactor was created prior to the bomb because it was inevitable and to test the theory that a reaction wouldn't run away indefinitely. The reactor created by the Manhattan project ran for about a year before being moved and rebuilt and then ran for another decade.
Can you not read at all? The reactor used in the Manhattan Project PRODUCED plutonium. It USED uranium. And it kept running because it was used to keep producing plutonium until '45 and then was used until '63 to produce radioactive isotopes for research. That's 20 years not 10 years.
>Here's a nobody that applied for a patent in 1936, you clearly don't know him LEO SZILARD
Incredible you didn't even read the comment because I literally mentioned Einstein and Szilard's joint letter.
CptHammer_ t1_japyqgr wrote
Ok then, have fun war mongering. You seem happy to war monger and wish to continue to war monger. I'd wish normal people peace but you're all too happy to fund new ways to kill each other by repeating and repeating the mistakes (sorry that's my opinion, you're probably seeing them as successes) of the past.
But, you know you can't get normal people on board with it unless you lie about the past and of course lie about the future.
Good afternoon.
wappleby t1_japzd6h wrote
Making up strawmen after being proven wrong over and over again. Absolutely incredible. And I never once mentioned anything about war or wanting war in any of my original comments.
And that's rich coming from someone who can't even get basic facts in their comments right.
CptHammer_ t1_jaq043u wrote
You didn't prove anything. So there's that. You just want to lie and you offered no proof for your position that the governments of the world don't automatically seek to weaponize any new technology.
There's actually plenty of evidence on your side at least in the short term, but you chose to shit on my rock solid proof that nuclear energy production also wasn't proposed to the public as a weapon first. You chose to ignore actual fact, produce no evidence all the while I took every one of your examples and proved you don't know what you're talking about, or specifically lying.
I don't know which one it is, nor does it matter because either way you clearly enjoy funding war.
I'm done with you.
Good afternoon.
could_use_a_snack t1_jakk1b5 wrote
>Done, now put your money where your mouth is.
My entire comment is basically doing this. I encourage the spending on scientific research and contribute to it when I can.
>Or answer this question: what's the best case scenario you can imagine that this research will help Earth?
We need to know what effect we can have on a dangerous asteroid. The only way is to run some tests to see. So the best case scenario is that we have the data available to make a correction to the orbit of such an object if we need to.
And before you ask "what's the chances of needing to" I'll compare it to having a fire extinguisher on hand in my house, even though most households never have a fire. I'd like to be prepared.
CptHammer_ t1_jaktgg6 wrote
>So the best case scenario is that we have the data available to make a correction to the orbit of such an object if we need to.
Wow, best case you can imagine is super limited. I thought for sure you'd go into astroid wrangling for convenience of mining. Nope, you're happy with, probably not going to need it, but if we spend an unbelievably higher amount of money then we might just maybe not kill ourselves unintentionally simultaneously ignoring petty issues on the big blue marble.
I'm just more confident that this technology will be used specifically to aim astroids at Earth. How do I know? Humans always say, "but this time it will be different." Sure resting on the fact that it's a technical difference in weapons, major advances that could change human civilization always, 100% of the time, get weaponized.
This is no different.
could_use_a_snack t1_jakvh5g wrote
This would be ridiculously hard to weaponize. You have to find an asteroid that was already coming extremely close to earth to be able to adjust its course enough to hit the earth, and then it wouldn't be possible to know where it would hit. And it would probably cost more than just dropping a bomb exactly on target by a factor of 10.
CptHammer_ t1_jal5p3i wrote
If we can get a vehicle to an asteroid using math, I'm pretty sure there's an equally simple formula to get on to earth at the appropriate time and space.
To speculate otherwise shows how dangerous you think the technology is at its current situation.
could_use_a_snack t1_jalbltl wrote
Sure. You can do the math, but moving a rock that weighs 1000s of pounds to actually change course is crazy hard. And would take a lot of energy.
Go look up the term "delta V" and read up a bit on it. 99.99% of the math to get that prob to hit the asteroid was done before it launched. If it was off by even a degree when it launched, they wouldn't have been able to correct its course enough to hit the target.
CptHammer_ t1_jalwwk6 wrote
>they wouldn't have been able to correct its course enough to hit the target.
Which is probably why you support more funding. We haven't perfected the weapon yet.
could_use_a_snack t1_jan4xdm wrote
>Which is probably why you support more funding. We haven't perfected the weapon yet.
Your statement shows that you are just trying to troll me. They did hit the target. Perfectly. Physics just makes it really hard to overcome an error. This will never be used as a weapon. It can't be.
I hope that you are either still in school and haven't taken basic 9th grade physics yet or have just forgotten what you have learned.
Either way, If you would like to have a reasonable conversation on this topic, you seem to be worried and I could help you understand that you don't need to be, I would suggest you brush up on orbital mechanics, and the launch capabilities that we currently have. Until then have a great day.
CptHammer_ t1_jaounbm wrote
>This will never be used as a weapon. It can't be.
You're saying basically it's impossible to do what they did. And you seem to also think that practice doesn't make perfect.
>I hope that you are either still in school and haven't taken basic 9th grade physics yet or have just forgotten what you have learned.
I've taught physics at a collegic level. This is barely a physics problem and more of an economic problem. We already know we can divert astroids, how much will it cost to put it where we want it?
You're probably unaware of proposals to aim astroids into a Mars orbit for mining. Mars orbit before lunar orbit just to prove we won't make accidents. Lunar orbits rather than earth orbits because we actually don't need much material back on earth. Only to replace the materials we sent to space. And of course it's an extra risk.
The idea of mining astroids in place is too dangerous and too costly as it's simply easier to bring things to the mill rather than moving mining operations so often. It's why we don't build a saw mill in every tree grove for lumber production, we move the logs to the mill.
could_use_a_snack t1_jap1qve wrote
You make some good points.
This is not what they did however. They didn't aim an asteroid anywhere. They caused it to change its orbit.
Yes you can move an asteroid to orbit a planet, but it will take years to do this. Making several minor adjustments over a long period of time. Not a great way to fire a weapon if everyone can see what you are doing for 3 years.
And the mill towns I've seen (I live in one that isn't one anymore) are always right next to the forest, if not in the middle. Moving huge trees is costly, you mill them as close to the source as possible and then transport the finished product to its destination.
And. If you did teach physics, I feel sorry for your students, anyone that doesn't want to see science funded shouldn't be teaching it.
CptHammer_ t1_japefzp wrote
>Not a great way to fire a weapon if everyone can see what you are doing for 3 years.
I don't think they're trying to hide it. Did you skip past the part where I said putting them in lunar orbit? It would take a push of the button at precisely the right time to send one to earth. Once they've been reduced to the appropriate size for the deviation they want to cause.
Even worse is if I'm wrong and a government isn't behind it but a terrorist. I'm telling you any perceived good is outweighed by the inevitable bad.
could_use_a_snack t1_jaq2wgn wrote
Wait, are you suggesting that what would amount to a trillion dollar industry capable of getting multiple asteroids into orbit around the moon, will be accomplished by a terrorist organization?
I'm done talking to you. You are just being ridiculous now.
CptHammer_ t1_jaqo8hh wrote
No, I'm saying once the benevolent portion of the plan is finished a terrorist could turn it into a weapon. I don't care how benevolent a plan you suggest any new technology will be weaponized.
It's like you're trying to suggest terrorists invented bombs with their own R&D to come to the conclusion you did.
CocoDaPuf t1_jan4exx wrote
This is one of the "realest" problems humanity has.
The dinosaurs went extinct. They died because of something they couldn't predict and had no control over. We have now gotten better at predicting asteroids and the dart tests show that we finally have control over the situation.
To contrast, I'll use climate change as an example of "a real problem".
Like asteroid impacts, climate change is another existential threat, but we've been able to predict the effects of it for nearly a hundred years and we've always had control over it (all we have to do is agree to change how we generate energy, build things and move things around). On some level, climate change has always been less of a problem for us, because it's a slow process the solution is so obvious.
Asteroids will happen suddenly and without warning if we aren't tracking every single object we can all the time... It's like we've been living on thin ice our whole lives, in constant danger, we just never think about it. We've never before had this kind of possibility of survival vs an asteroid.
119defender t1_janl3hu wrote
I believe your outlook is incredibly shortsighted. The "dinosaurs" went extinct because they had no control? hmm, so if they could have banded together built towering weapon systems and blew the asteroid out of the sky then all would have been well I guess? How about quite possibly the dinosaurs were eating their children and were very destructive, even destroying Gods creation to the point he sent said asteroid to wipe them out! Today a bunch of men who are dinosaurs want to blow you and my family off the face of the earth with nuclear weapons because they are power hungry, blood thirsty and greedy! Sure each group believes they are right but the creator knows who is deadly and who really is the dinosaur that refuses to change, refuses to disarm, refuses to learn and desires blood. These same dinosaurs are in space ready to blow up more planets if you give them a chance. Maybe its time for the dinosaur people to end and a people of peace lead the way! Just a thought!
mattstorm360 t1_jaimol0 wrote
Like asteroids hitting Texas.
Neethis t1_jaiyofh wrote
You mean we should be spending money to make asteroids hit Texas, right?
chase2121dw t1_jaiyz62 wrote
Sandy Cheeks is going to need to have a word with you.
Ouatcheur t1_jalp0b6 wrote
Nope, all those human-made asteroids are already all reserved to be eventually dropped on Ohio.
'Cause Ohio be like!
Targeting Texas however that would be a waste as it would just make 'em all even tougher.
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[deleted] t1_jamsrih wrote
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mistaekNot t1_jaj4cfi wrote
there is more than enough money in the world to spend both on real and unreal problems. the real problem is wealth distribution / inequality… tax the rich!
stupid_cat_face t1_jajmg63 wrote
So..... you're saying ... there is a chance.
SnooSprouts1590 t1_jakg4g5 wrote
But is it possible for something the same size as Dimorphos to hit earth?
MozeeToby t1_jakmmir wrote
Yes, that's why this mission was important. Let's say we see an asteroid this size a few orbits before it's going to collide with Earth. We could launch a mission similar to this DART impactor and change the asteroid's orbit by 30 minutes per orbit.
That may not seem like much, but if it's still 2 orbits before impact that's an hour difference. The asteroid now misses Earth by about 60,000 km.
mfb- t1_jal2tc5 wrote
It's 30 minutes difference in the orbit around Didymos, an orbital motion with a tiny orbital velocity (~18 cm/s). The impact changed the velocity by around 1 cm/s. Over 2 years and for a free-flying asteroid that accumulates to 600 km in the best case. We would need a larger impactor (or many) for this scenario.
identicles t1_jalgvcc wrote
Which, as a casual observer, doesn’t seem unreasonable if the fate of civilization is on the line. (This comment is aware of the the impending doom of man-made climate change. Only thinking about the ability of the global community's ability to potentially mobilize around a less-abstract threat to our existence)
mfb- t1_jalosan wrote
Something the size of Dimorphos can produce regional devastation but it's not a global threat.
TolMera t1_jalw4wh wrote
And if it did, we already tested and proved we can crash something into it and redirect it again lol
[deleted] t1_jajl8b5 wrote
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DBDude t1_jaitei1 wrote
Fun fact: If you Google NASA DART, the spacecraft will fly into the page, which gets hit and stays crooked.
zanraptora t1_jaixz7y wrote
To be clearer, the phrase that does that is "DART Mission".
BimphyRedixler t1_jaizu9p wrote
For the lazy: google.com/search?q=DART+Mission
UltorMiner t1_jaliluu wrote
Didn’t work for me, but nasa dart did
Shotgun5250 t1_jaj04yl wrote
But is the page exactly 33’ of rotation?
DBDude t1_jaj2v8d wrote
Quite a bit more, I’d say a few degrees.
[deleted] t1_jaj4yeu wrote
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Darwins_Dog t1_jak3xec wrote
I don't think you'd be able to see that. 33 minutes is 0.55 degrees.
[deleted] t1_jaiuxfr wrote
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Embite t1_jaijci7 wrote
I remember in the headlines after the impact everybody was amazed by how much more energy the probe delivered than predicted. Why were we so pessimistic? Isn't this a basic inelastic collision problem?
zeeblecroid t1_jail3qv wrote
I think they were expecting Dimorphos to be a lot less squishy than it turned out. Instead of hitting a rock, the spacecraft struck a rubble pile, and was able to penetrate enough to dump most of its energy into Dimorphos rather than just dumping it onto Dimorphos.
12edDawn t1_jaioiza wrote
I still don't understand why those two are different.
lagavulinski t1_jaiqukb wrote
Imagine a cinder block covered in 6 inches of compacted sand. You shoot it, and the bullet dissipates most of its energy hitting the sand. Now imagine a cinder block covered in 6 inches of loose sand just floating around it and barely touching it. You shoot it, and the bullet goes through most of the sand and hits the core of the cinder block, visibly moving it with all the energy.
Kear_Bear_3747 t1_jaje1p9 wrote
That’s not how it works in space bro
lagavulinski t1_jajernq wrote
If you don't mind elaborating on what I've said incorrectly, I'd appreciate it so I can edit my comment. :)
Kear_Bear_3747 t1_jajfhid wrote
In space, objects will absorb all of the momentum of the object. That’s basic Newtonian Physics, dealing with Inertia.
On Earth it matters because there are other forces in play like Gravity and Friction so kinetic energy can dissipate in different ways, whereas in space there’s nothing to arrest that energy, it will impart itself on whatever object it collides with.
lagavulinski t1_jajh7fb wrote
Thanks for the explanation. However, I believe you and I aren't discussing the same thing. I do agree with your explanation of Newtonian physics though.
coriolis7 t1_jajr75p wrote
Not exactly. Momentum is always conserved, but the kinetic energy is not. A fully elastic collision preserves kinetic energy, while a partially inelastic collision does not.
In both cases m1 x v1(initial) + m2 x v2(initial) = m1 x v1(final) + m2 x v2(final).
However, only in the fully elastic collision does the following hold: [m1 x v1(initial) + m2 x v2(initial)] / 2 = [m1 x v1(final) + m2 x v2(final)] / 2
It doesn’t matter if it’s in space, in a lab, or wherever.
I think what the above redditor was saying is that because the outer material was more loosely held, more of the material could be ejected. That ejected material has additional momentum. Even though the probe never bounced off (ie elastic collision) the ejected material made the collision act as partially elastic.
workingdad83 t1_jaju14g wrote
Oh yeah. 2√(brdsrntreel)+2 carry the 4. See I can just push a lot of buttons too.
Joking. I know you are smarter than me, and I was lashing out. I'm sorry.
gdpoc t1_jajjufm wrote
Doesn't it also matter whether what you're hitting is an isotropic homogeneous solid and how much of that is aggregate v fill when we talk about celestial body surface composition?
[deleted] t1_jajqpyp wrote
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ResponsiblePumpkin60 t1_jajzk3m wrote
I think the only thing that matters is how much energy is lost from ejecting impact debris off into space. If none is ejected, then no energy is lost.
Tuna-Fish2 t1_jajnj3b wrote
In an inelastic collision, momentum is conserved. So Sum(momentum of all bodies) is the same before and after the collision.
If Dimorphos was a rigid body, the spacecraft would only add it's own momentum to it.
However, because the impact by the spacecraft caused just loads of material to be thrown off, the end momentum of Dimorphos is old_momentum + dart_momentum - sum(momentum of all the ejecta). Since the ejecta is going the other way, the net effect is that dimorphos was accelerated more.
(Remember, kinetic energy = ½mv^2, momentum = mv, so spreading out the energy over more, heavier objects increases efficiency.)
Kwiatkowski t1_jalbktv wrote
someone else probably will do the maths better but I’d bet because if the squishiness it transferred more of its kinetic energy into the target instead of converting it into more heat which would be the result of a more solid hit. Don’t trust me tho, just my thought on how it works
nagabalashka t1_jajdiho wrote
Explode a balloon in front of your hand, you're fine, you feel the burst but nothing more.
Explode the same balloon in your ass and you'll be in pain.
pete_ape t1_jajo7f9 wrote
Soooo... Dimorphos got creampied by NASA?
Embite t1_jaimb6e wrote
If Dimorphos was a solid rock, though, there wouldn't be anywhere for the energy to go but into the asteroid. The shrapnel from the impact would have to bounce backwards or sideways, which would just add to the momentum along the approach vector.
SirLauncelot t1_jajdmou wrote
If it bounces off, that means a lot of the energy was reflected back. If it takes greater time to sink into the asteroid, more energy is transferred.
Embite t1_jajvgby wrote
If shrapnel bounces off the asteroid but doesn't accelerate it that would violate conservation of momentum?
Ouatcheur t1_jalot2h wrote
Nope. The energy that is trsnsferred from the DART to the asteroid CANNOT be higher than the initial kinetic energy it has initially, no matter the way it penetrates the asteroids.
You don't get energy out of nothing!
But people often ignnore that the total enerrgy before must equal the totlal enerrgy after.
And before it is:
DART + ASTEROID.
And after is is:
now-a-bit-saller-ASTEROID + its-EJECTA
People just tend to ignore the ejecta.
so in their minds it is
DART + ASTEROID(before) = ASTEROID(after)
or even worse it is:
DART + ASTEROID(before) + magicalwaytheimpacthappened = ASTEROID(after).
Like in "Oh it hit the dense core so it transferred MORE energy". Morer energy than what exactly? The DART fully crasthe asteroid, its, so it's gonna give 100% of it's kinetic energy no matter what. No "it transfers more than 100% because it hit something more solid". Duuh huuh huuh.
Sp, always remember the ejecta. And note that the ejecta is mostly ejected in the OTHER direction.
So the *only* way for the kinetic equations to balance out is for the asteroid to move faster once accounting for its ejecta (faster than if there hadn't been any ejecta at all).
The solidity of the "central" core part is irrelevant.
As the DART experiment proved, the amount of ejecta gives a MAJOR effect to the results.
mistaekNot t1_jaj55j4 wrote
some of the energy is in the shrapnels speed. if the spacecraft gets buried into the dimorphos then all of its energy is transferred into dimorphos
Impossible-Error166 t1_jaj9pml wrote
Its also how much the asteroid breaks apart and if gravity will pull it together.
rocketsocks t1_jajtzbs wrote
They were always expecting dimorphos to be a rubble pile. That's the whole reason they did the mission, to collect this data, because there are unknowns involved.
rocketsocks t1_jajtuvr wrote
It's not about pessimism it's about the difficulty of simulation, and lack of detailed knowledge.
And no, this is not a simple inelastic collision problem, it's not simply a matter of the final momentum of the asteroid being its starting momentum plus the probe's momentum, if it were we wouldn't have sent the probe. The asteroid is a rubble pile, which means that the impact ejected a huge plume of debris out of a crater. Because it sends a debris plume backwards (and that momentum needs to be balanced) you get greater than 1:1 momentum transfer, essentially turning the crater into a rocket engine powered by the probe's kinetic energy. The details of that plume depend greatly on the compositional and structure details of the asteroid, something we have very little firm data on up until now. We have literally fewer than five data points to go on for this sort of thing. So folks put together some simulations with variations according to the knowledge we have. As it turned out in this one instance the result was on the high end of all of the simulations, well above the average.
One thing worth pointing out here is that this is still just one data point. It may be that dimorphos is actually an outlier in terms of its compositional structure. Or it may be that the particular spot we hit was unusual. The average could be lower or higher than what we achieved with this specific instance. That's why we need a lot more studies like this one to collect enough data to be actually of practical usefulness.
CocoDaPuf t1_jan8kbi wrote
This is the most accurate and clearest answer I've seen to this question. Great job with this post!
Erinalope t1_jajc7cz wrote
Scientists are typically pessimistic with unknown variables and there may have been other forces at work that added to the effect. They’ll study the results plus the ESA is sending a follow up mission to the asteroid which will add to the data. There’s still so little we know about asteroids it might not be a bad idea to do a dart 2 with a lander to examine a different type of asteroid interior more closely.
Second_Sol t1_jakpukk wrote
It's not quite so simple, Dimorphos turned out to have a lot of loose rubble, so the impact created a lot of ejecta going the opposite direction of the site of impact, which means you get a greater pushing effect.
Imagine tossing a sticky ball at metal cube in space.
The ball will stick to the cube and they'll float away at a slower velocity than what the ball originally had
If you toss a rubber bouncy ball of the same mass at the same velocity, it'll bounce away from the metal cube, and come flying back at you while the cube will float away faster than if you used the sticky ball
MattC1977 t1_jajewbx wrote
“Altered the orbit of the asteroid by 33 minutes “
Can someone ELI5 that for me? Does “33 minutes” translate to feet, yards, miles?
zeeblecroid t1_jajjw9a wrote
It translates to minutes. Dimorphos completes an orbit in 33 fewer minutes than it did before it got smacked.
aerowtf t1_jakmdvq wrote
it changes the shape of the orbit, making it slightly tighter or wider, which also corresponds to time
TyrannoFan t1_jal81qr wrote
It represents the change in how long the asteroid will take to complete an orbit around the sun. It might not sound like much in the context of years-long orbits, but if this change in orbit can be enacted early enough and in the right direction, it can be the difference between the asteroid eventually striking Earth directly or missing it.
Think about a car driving down a road at 60mph. Let's say that 60 miles down the road, someone will walk across the road, let's call them Earth, and they won't be paying attention to traffic, idk maybe they're on their phone and have earphones in. In 1hr, the car will cross paths with Earth and run them over assuming it doesn't slow down. If you try and slow it down right as it's gonna hit Earth, you'll have to really slam on the breaks, and even then it might be too late. But if you intervene 1hr in advance and slow the car down ever so slightly such that the car arrives at where Earth crosses the road just a few seconds later, the crisis is averted with very little energy spent.
That's the exact same principle behind asteroid redirection efforts like this. Hope it helps.
gobblox38 t1_jal0lpq wrote
These are arc minutes. There are 360° in a circle, 60 minutes in a degree, and 60 seconds in a minute.
On earth, an arc minute along a great circle is equal to a nautical mile. The conversion to any unit of length depends on the radius of the rotation. If the orbit is elliptical, the equation gets more complicated.
EDIT: I was totally incorrect about what they were talking about. See daughter post for details.
TKtommmy t1_jal2jo6 wrote
No, we're talking the orbital period in time. Actual minutes of time.
gobblox38 t1_jal5eri wrote
>Based on the change in the binary orbit period^2 , we find an instantaneous reduction in Dimorphos’s along-track orbital velocity component of 2.70 ± 0.10 mm s^–1
I should have read the article more closely. I thought they meant the angle changed when what really happened is the speed reduction increased the orbital period by 33 minutes.
After giving some consideration as to why they'd write it like that, it makes sense. Changing the orbital period by an amount of time may be enough for another orbiting body to get out of the way.
My bias got in the way of this one, thanks for the correction.
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___________a t1_jakch5b wrote
Anyone else here wondering what the heck happened with LICIACube? Did it actually end up failing? A perfect, close observer, yet has remained silent since impact really.
soldato_fantasma t1_jalhzyu wrote
It did work fine, it got more than 600 pictures of the impact during it's flyby and they were downloaded. Only a handful were released by ASI, the Italian Space Agency, though. Here you can find the pictures that were released: https://www.nasa.gov/feature/first-images-from-italian-space-agency-s-liciacube-satellite/ https://www.esa.int/ESA_Multimedia/Images/2022/10/LICIACube_image_of_asteroid_ejecta Two animations were also shown in a NASA press conference, but I can't find it
ocicrab t1_janx4d1 wrote
At least one of the animations is near the end of the video that OP linked
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rocketsocks t1_jajbgi0 wrote
That would be less valuable than other studies. DART with Dimorphos is one data point, to gain enough knowledge of the problem space to be able to build actual asteroid diversion systems based on the principle would require a lot more data points (realistically dozens). We need to understand the variations of how rubble pile asteroids are built, the range of possible impact dynamics, and what levels of predictability can be expected along with what features and measurable aspects can be relied on to guide that predictability. It may be that the next rubble pile asteroid we try to do this with is twice as effective, or half as effective, or maybe not effective at all, we don't have that data yet. DART is really just the first step of a long journey towards building the technology of asteroid diversion, and it is also not the only way to do it. It's a technique that will work in some situations but not others.
A lot of people imagine DART as being like this prototype of a system that we can just pull off the shelf and use to save humanity, but it's just basic research into the problem space, it's nowhere near anything like a prototype.
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Loki-Don t1_jaky5zh wrote
That is an enormous effect. Dimorphis was 560 feet in diameter. It was about the size and mass of the great Pyramid at Giza. If it hit the earth, it would completely destroy everything within a 10 mile radius and creat earth quakes that would be felt up to 1000 miles away. It would be worse if it hit water as the tsunami effect would flood nearly 70% of the globes ocean coast lines, killing an untold number.
If we can redirect something that size, then it should scale upwards from there. Just need to detect it early enough
Whoelselikeants t1_jalxigb wrote
Dimorphos was “rubble pile” asteroid so the chance of it getting through the atmosphere wasn’t much probably.
Fuzakenaideyo t1_jajocdb wrote
I can't seem to find out if liciacube is still active or not does anyone know
Madouc t1_jajwtg9 wrote
Good news, now we only need to spot them early enough.
happydaddydoody t1_jakd9rh wrote
Question. This was a single mission. It definitively proves the theory? I mean aren’t different objects composed of different things? Wouldn’t more attempts help solidify proof?
gobblox38 t1_jal1u0n wrote
If you want to split hairs, it's impossible to prove a theory. But this mission did verify the theory. Another test can further verify the theory or break it. We won't know for sure until we do another test.
In other words, yes, more tests are needed to get a better idea.
Whoelselikeants t1_jalwvhu wrote
I would say it’s more like a proof of concept. It works and can be used but is it reasonable? Sort of like how Ingenuity is used on mars, yes you can fly a helicopter on mars but is it cost effective/reasonable?
Starks t1_jajadty wrote
Does DART scale up though? Would it be better to have a fleet of them, larger ones, or have more generic gravity tractors ready for longer-term defense options?
arkham1010 t1_jajthiw wrote
Apparently there were plans for a bigger DART, called the Longer Adjustment Wide Nacelle, or LAWN-DART for short. However it was found that too many children were injured during research into LAWN-DARTS so the program was scrapped.
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rocketsocks t1_jajul22 wrote
It scales up to some degree. There are lots of different kinds of asteroids which might be a threat to Earth. The DART data represents the first entry in a spreadsheet which might be filled out well enough to start having confidence in one way to divert rubble pile asteroids.
What that could look like eventually in a hypothetical practical application would be a medium sized asteroid that was a threat many years (hopefully decades or centuries) into the future and a series of impactor vehicles being sent to apply a sufficient set of nudges to divert it away from the impact scenario. Realistically anything like that would be part of a family of systems with different operational characteristics to handle different bodies of different scales of threat over different timelines.
Eaton_Rifles t1_jalhv6n wrote
Maybe it’s an asteroids game sort of approach, so you hit a smaller asteroid adjusting it’s orbit, bits of that then slam into the threatening asteroid with more effect than just using the original impact object...👍
definitlynotchichi t1_jaknohe wrote
All of this will come with further research
Ouatcheur t1_jalmv6b wrote
And in the case of gravity tractors: Lots and lots more further research. Maybe even an infinite amount of further research.
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SagemanKR t1_jaltxwz wrote
The initial goal was to reduce Dimorphos' orbit period by (minimum) 73 seconds.
The impact surpassed the benchmark by more than 25 times!
kmaxile t1_jajrc5l wrote
How could DART take and transmit such a clear picture close to the surface when it hits Dimorphos at 6 km/s?
aeneasaquinas t1_jakb9z1 wrote
Big camera, wide lens, and good optics.
FWIW the final image is half missing
Shas_Erra t1_jalj85c wrote
There was a Kerbal perched on the side of the craft
Ouatcheur t1_jalmnj2 wrote
Moving fast doesn't screw radio signals up. Not unless you move at relativistic speeds in which case all it does is change the speed (the frequency and the data rate) of the signal. Not "jumble it out".
But 6 km/s while it sewsmc fast for us at ground level, it pitifullly slow when comparing to light speed. the relativistic Lorentz transformation effect aat such relative speeds is so tiny as to be completely ignorable.
And there is no atmosphere in space, either, so moving fast won't shake you around like a plane flying too fast beyond it's structural limits and being destroyed by air turbulences. There is no "wall of air" in front of you to constantly apply friction and slow you down: there is (next to) nothing! Basically, ideal conditions for moving around.
It is not the engine's power and speed that gives off that 6 km/s. It is the slow ACCUMULATION of speed by the engines. Forget Hollywood sci-fi when they nearly instantly reachh full speed when they lit the engines, then magicallly slow down to a stop when they turn the engines off. Things don't work like that in reality. At all. Think more like this: your spaceship has a speed vector. Each time unit, you move by that speed vector. It doesn't matter if you rotate where your ship is pointing at, it moves in the same direction of that vector. That is called inertia: things tend to keep on moving the same way unless a force is applied to them to counteract that. Now, you have engines, but all they do is, each time unit, add a TINY speed vector. Say, after accelerating for one hour, you are now moving 5 km/s from bottom to top. You could turn the ship sideways to turn to the "right" and lit your engines for say another hour. Then you'd be moving the same 5 km/s from bottom to top PLUS 5 km/s from left to right, thus now your speed vector is about 7.4 km/s going "top and right".
It takes a long time to accelerate something to 5 km/s. For comparison the fastest hypersonic jet known movves at Mach 6.72 = 4520 mph = just about 2 km/s. And that is with a jet with a superbly monstrous and HEAVY engine, that can use the abundant "thick" air it travels through as for it's oxygen for nburning it's fuel much hotter. Not the measly "built to work in space" engine of a little very fragile satellite. These two things can't even be compared.
Presumably, DART's propulsion systems were turned off for its very final segment, letting DART final closing in "sail through" mode, without any engines vibrations in other to get the best images. No atmosphere, means no vibrations and no friction. And very clear images, too. Once you turn the engines off, you just keep on moving inertially at the same speed.
From the point of view of DART, once itS' engines are off, it is immobile and it is Dimorphos that is closing towards it at 6 km/s. Not the other way around.
Because Special Relativity, ya know.
mandozombie t1_jak0lfm wrote
Then They could be steered by rockets posibly even for the purpose of mining.
trancepx t1_jals6l2 wrote
These moonlets on reddit didn't even know moonlet was a word until now.
[deleted] t1_jaihyzr wrote
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Djasdalabala t1_jaje456 wrote
Note that while this is an effective method to steer an asteroid, the difficulty scales with its mass and delay before impact. This would not be practical in a (very unlikely) "don't look up" scenario, where the asteroid is huge and discovered only a couple of months from impact.
[deleted] t1_jajziki wrote
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EazyPeazyLemonSqueaz t1_jal562w wrote
I wonder what the cutoff is for the size of an asteroid that would spur this kind of mission
[deleted] t1_jal7uhd wrote
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[deleted] t1_jal94u1 wrote
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[deleted] t1_jalcxyr wrote
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Freecz t1_jalg4od wrote
Dumb question, but what does it mean that the orbit was altered by 33 min? Also is that a lot?
ForgiLaGeord t1_jankvmo wrote
The asteroid they struck orbits another asteroid, and now that orbit takes 33 fewer minutes to complete.
Freecz t1_jao5p5h wrote
Oh I didn't know that. Very cool. Thanks for the information!
youreblockingmyshot t1_jaljrpq wrote
I wonder how big of a kinetic redirect satellite you could get up there with starship if that thing gets reliably orbital.
TryingToBeReallyCool t1_jallkeh wrote
Good to know we'll be ready for the covanant when they show up
[deleted] t1_jaln7vn wrote
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[deleted] t1_jaof8zw wrote
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Decronym t1_japjh6c wrote
Acronyms, initialisms, abbreviations, contractions, and other phrases which expand to something larger, that I've seen in this thread:
|Fewer Letters|More Letters| |-------|---------|---| |CC|Commercial Crew program| | |Capsule Communicator (ground support)| |ESA|European Space Agency| |LEO|Low Earth Orbit (180-2000km)| | |Law Enforcement Officer (most often mentioned during transport operations)|
|Jargon|Definition| |-------|---------|---| |periapsis|Lowest point in an elliptical orbit (when the orbiter is fastest)|
^(4 acronyms in this thread; )^(the most compressed thread commented on today)^( has 16 acronyms.)
^([Thread #8641 for this sub, first seen 3rd Mar 2023, 03:00])
^[FAQ] ^([Full list]) ^[Contact] ^([Source code])
Ouatcheur t1_jall102 wrote
Orbit duration is a zilch-usefulness information.
What we need to know is by how much would an actual asteroid deflected (angle), and that is determine by the inverse square of it's speed.
i.e. an asteroid twice as masssive need a blast twice as big to be deflected by the same total angle. But an asteroid twice as fast, needs a blast FOUR TIMES as big. Kinetic Energy is proportional to square of speed after all.
I searched everywhere, found that pre-impact orbital velopcity was either 0.174 or 0.177 m/s. No word on the post-impact orbital velocity.
The about 11 hours orbit was lengthened by about half an hour. Supposedly, this means if you slowed down the thing by about 1/22 of it's pre-impact speed, then it's post impact speed would give just about that time interval for it's new post-impact orbit.
Going from 0.177 m/s to 0.167 m/s is a measly 1 *centimeter* per second speed vector change, in this case here a reduction, but it could be in any direction, really.
Also, found zero data on actual angular effects, too.
A real, typical asteroid moves at what, 18 km/s, average?
Does this mean that for this "planetary defense" thing to work, we'd have to scale it up by a factor of about 1 800 000 ? Just to get the same amount of angular deflection?
Good luck with that, I guess.
I think they focus only on giving the "whopping" 32 minutes orbital revolution slowdown change, because if they told the entire story clearly, that the dimorphos asteroid was deflected only by a measly 1 centimeter per second, then everybody would immediately see that this "solution" is laughably NEVER going to successfully "defend" us vs an actual asteroid coming for us.
Accelelolita t1_jam5av4 wrote
> typical asteroid moves at what, 18 km/s, average?
Get off wikipedia and go hit the astrophysics books lmao.
Ouatcheur t1_jauvidx wrote
Get off your dusty old books dating from before relativity explained Mercury's recession, and just put a bit more faith in actually fact checking reliable sources directly yourself?
Also, please get off your high horse. When you come with such an agressive attitude, the impetus is on you to prove your point, instead of just doing nothing more useful than throwing the cheap blow of an Ad Hominem without any extra substance to it than that.
That 18 km/s figure comes from the Lunar and Planetary Institute.
https://www.psi.edu/epo/ktimpact/ktimpact.html says :
Asteroids hit Earth typically at high speeds of 16 to 32 km/sec
Some move way faster and those are the really most dangerous ones. The 18 km/s is just some average, the reality is of course a spectrum.
That one is said to move "at warp speed" but it is moving at about "only" 6 km/hour. STILL at about twice the size of dimorphos it remains a super dangerous potential extinction event.
Still, the overall logic remains true within an order of magnitude for more or less similarly sized, similar speed asteroids.
Keep on laughing your ass off and judging others while actually contributing absolutely nothing that would be actually useful to the discussion. Congratulations!
cant-login-to-main t1_jatda8r wrote
Bruh, go read up on orbital mechanics or something. You really think you know better than the scientists that worked on this mission?
Ouatcheur t1_jautk5r wrote
No I don't I never said or even implied it, it's you projecting something on me that just ain't there. I think you deeply misread me anbd my intent. Of course such an experiment is a vital one. But all media even NASA website definitely focus only on the half hour differential over the previous 11 hours orbit, and very hard to find data on the actual resulting delta V.
It is cherry picked information to make it seems as if it was a huge effect, but while it is indeed a huge accomplishment, in terms of actual delta V this is a tiny effect.
It is way too easy to just say "Go learn this!" in a condescending and dismissive way. While without correcting anything.
Well, I checked my numbers. Did you? I dare you to do the same computations yourself. And yeah when just trying to get a ball park figure, you are allowed to use simplified formulas, as long as they don't introduce "orders of magnitude" errors. No need to be a "scientist", kinetic energy formulas are simple.
And for tiny angles, sin (angle) is proportional to the angle.
Inverse proportional relationship: Mass <===> Resulting Delta V.
Inverse square proportional relationship: Speed <===> Kinetic energy ==> Resulting angle differential (for small angles) obtained from applying some force.
It's not rocket science. Orbital speed of dimorphos around it's primary is one thing, and it is super slow. Overall speed of a typical asteroid is over ten thousand times higher.
So with DART we got a resulting Delta V of 1 of a centimeter per second.
Over a year, that is approx less than 300 kilometers of deviation. This is only an order of magnitude value here as of couse orbital mechanics mean curved, not straight, trajectories. But the deviation remains a small one. The compounding effects won't magically stack up to somehow give superbly different total values for the final asteroid's position.
But here we want to deflect an asteroid so that it "misses Earth". This means we have to (at most) speed it up or slow it down or deviate it by approx 6500 kilometers (half the Earth's width). So you have to catch the asteroid really early on, or apply way more force than DART did, to succeed. Or preferably, both.
The media is all gloating about the "huge feat" without also talking about how you'd need scores and scores of DARTs to do the ACTUAL job of deviating an actual asteroid successfully, not just apply a super tiny actual delta V to it's orbital period. Something beyond our capabilities. "Just send a more massive DART that moves faster, and/or send a lot of DARTS", that means requiring a LOT more fuel.
We are still far from having a valid asteroid planetary shield defense. Very far. It doesn't take "top scientists" to see that, just checking the numbers at a very basic level and yet at a little bit more depth than just the surface evaluation of "Oh wow half an hour of an 11 orbit that is like about 1/20 of the job done!" when the ACTUAL job isn't changing a slow orbital speed by 1 centimeter per second, but changing a way faster collision vector speed by a whopping lot more.
DART is cool and all, but it fails to properly show how huge the task really is.
GuyD427 t1_jal2108 wrote
I have no problem with public funding for this type of experiment. But, isn’t it obvious that detonating a nuke at the right spot on the asteroid is the way to really make sure you are changing the trajectory?
bookers555 t1_jaqhylb wrote
Yes, but launching a nuke on top of a satellite would be way more complex and expensive, plus you'd be violating a few treaties.
Not to mention you dont want to screw around the kind of asteroid that wouldnt just get obliterated by the nuke. The point was analyzing how much of an effect a kinetic impactor would have on an asteroid.
curvebombr t1_jaj92uu wrote
For those that don't know, minutes are a measure of angles. One minute of angle is roughly equal to 1in at 100yard distance. So, 33 minutes is quite a substantial change at this distance.
Tuna-Fish2 t1_jajnxop wrote
In this case, it's just a measure of time. Dimorphos is in orbit around Didymos. This is why it was chosen as a target, because we can very accurately measure the difference in the length of it's orbit before and after collision.
zeeblecroid t1_jajjli1 wrote
No, 33 minutes is 1980 seconds, because the article is specifically referring to the orbital period.
curvebombr t1_jajl8ri wrote
TIL, I was under the impression it was the degree of change in the orbit not length of time to orbit.
TKtommmy t1_jal3b0u wrote
The shape of orbits are not measured in minutes, there are multiple variables.
zeeblecroid t1_jaicv8h wrote
To head off the usual flood of identical comments that seem to come up every single time this mission's mentioned: no, there is no possibility, zero, none whatsoever, that Dimorphos will somehow fly out of its orbit and hit Earth (or any other planet). It ain't gonna happen, that's known for certain, stop reflex-fretting about it.