I've listened to about a half dozen people explaining this, and Dr B is the only one who hasn't fallen into jargon. I actually understood your entire explanation.
The trouble is none of what she said is true. 1) It is a fact of mathematics that the precision of the total calculation can NEVER be greater than the precision of the least precise measured factor or variable. 2) They will never have enough data about the size shape and density of the target asteroid to make useful calculations ever. Any measurement of the mass and the velocity of the ejected dust will be at best what we called in engineering a WAG - a Wild Ass Guess. This means the best answer they can possibly arrive at is also a WAG.. 3) They could have made that WAG 5-30 minutes after they had they new orbital time or they can never make it at all. There will never be any better data to be had. 4) The next asteroid will be of a completely different composition and density so there will be almost zero transferability of this data to future tests. You would have to run 500 of these tests on different types of asteroids to get anything vaguely useful. . 5) The only real reason for the delay is that presenting the calculations immediately is not impressive enough to politicians to justify the money spent and for future tests. They have to make it look hard. 6) She buzzed right past the most interesting point. Hitting the asteroid did NOT slow it down. It speeded it up! They must have hit it while it was moving away from them. Why would they do that? If you are trying to deflect or stop something you hit it either head on or at an angle on the front as it is coming at you.
@@johnbreitmeier3268 no. None of what YOU said is true. They have plenty of instruments and data to make very precise measurements and predictions. There's nothing WAG about this, it's good science. And re: point 6, the orbit was reduced which corresponds to a reduction in orbital velocity.
@@TimHollingsworth80 Timmy My orbital physics is rusty so you MAY be right on 6) BUT I am absolutely right on the WAG. You did not listen closely. She TOLD you plainly it was a WAG. Things they have zero way of knowing: 1) What the asteroid was make of. If you looked at the picture it is a loosely bound ball of random space junk. There is no way of knowing the density, what it was even mostly made of. 2) There is no way of knowing if there were internal voids or how many. This affects the mass greatly. 3) No way to accurately guess even the volume of a lumpy mass they saw one side of. 4) Absolutely zero way to even wildly guess how much stuff of what mass was ejected at what speed in what directions to be able to reduce that to a single resultant recoil vector for a calculation. If 1% of the total mass of the asteroid was ejected then that is negligible and can be discounted. If it is > that 25% certainly not. Do they have a clue. They do not seem to. You can very accurately measure a few things but if you cannot precisely measure even one variable the precision of the answer is reduced to the precision of that variable. All the rest of the expensive precise measurements were wasted and useless. People like you were not rained to understand this. You watch the shiny object and go OOOOH! You have a boatload of WAGS going into this calculation and all that can possibly come out is a WAG. If you know the beginning and ending mass of the asteroid to a guess of one significant figure (and that would be a stroke of luck) you just get a guess at one significant figure out. Look up what a significant figure is. I was a "top government scientist" and engineer for years. I know the dance steps.
It's sad that the media hasn't made a bigger deal out of this. This team has provided a proof of concept that could potentially save our entire civilization, along with every other living thing on the planet. It is a huge step toward ensuring the long term survival of our species. They have my utmost respect and most sincere gratitude.
To eradicate all life it would take enough impact energy to evaporate the oceans and melt all of earths crust, and even then life might survive frozen inside orbital debris, waiting for the crust to solidify and the oceans to pour from the heavens, that could survive reentry if it happens to aerobreak in the right way and life would be back on earth and might conquer it anew. Who knows, maybe that even happened already, we don't know.
@@jannikheidemann3805 But to destroy our civilization, or have an impact that could destroy the economy of a nation state, it would take much much less than you describe.
I agree it’s hard that more isn’t still out there from common media, but the truth is the US had the most miserable mid term election fight in my lifetime, and a War that could make the worry about an asteroid hitting an Earth burned by a nuclear snowball fight.
I can't imagine the person sitting there to observe the time change only to find out that it was 30x greater than expected. They probably did a double take, cleaned their glasses, bumped their monitor, ran whatever associated test/program there was again several times, and then just sat there absolutely astounded.
Nah, I bet that was in the expected range. The main reason we couldn't have a concrete estimation was due to missing data about the composition of the asteroid and it being new data about such a mission as a whole.
i genuinely think they way underestimate so that they are more likely to meet the goal. similar to how they underestimate the service life of the mars rovers & such. to be fair to NASA this basically what i do when i set goals for my life LMAO
What impressed me most was the accuracy of the bombing of dimorphos. Hitting something 7 million miles away that is a moving target about the size of a football stadium is a lot of math. Orbital mechanics and rocket science. backed up by a lot of electronics, optics and visionaries.
It's not that hard, to be honest, the tracking software is basic as shit, and overlay that is in camera software, and boom you hand that over to engineers
@@tonyw8001 I'm not privy to the specifics, myself, but I bet this is pretty accurate. Computers make the hard calcs easier, and with the right programs, much, much easier.
Love your videos and what an exciting update! One little math correction on this one: The change in kinetic energy of the asteroid is 1/2m(vf^2 -vi^2), which is not the same as 1/2m(vf-vi)^2 or 1/2m(delta v)^2 as you wrote. For fun, I was planning on having my physics students calculate how many Joules of (negative) work was done on Dimorphos by the impact and compare it to the kinetic energy of DART before impact. We can use Kepler's laws to derive the initial and final velocities given the orbital period and semimajor axes before and after but if you happen to know the initial and final velocities of Dimorphos, please list them! We'd assume a negligible change in mass of the asteroid. Thanks!
I came here to say exactly the same thing. My Engineering soul screamed a bit when I saw that. Bad Dr Becky. :D Don't worry we still think you are awesome.
Energy is not conserved in inelastic collisions like this, but momentum always is. Using simplifying assumptions for the ejecta plume properties, you can calculate the delta v very simply.
Fascinating. The September issue of Sky and Telescope has an excellent article explaining the impact physics. I am surprised they had that large of a velocity change. Well, that's why we always test!
From Scott Manley's analysis of the images showing the typical particle size on Didymos i.e. the lack of anything smaller than large boulders and the early images of the accompanying cube sat of the out flow response from the asteroid it starts to make a lot more sense after all the plume outflows were crazy complex with eruptions of material emerging from the depths of the asteroid all over its surface. I would bet most of that ejecta escaped into space and thus pretty much all contributed to changes in Didymos's orbital angular momentum.
I'm only certain I've gotten the real scoop when I've heard your take on the subject, you're so transparently telling it exactly as it is the best you can, which is crystal-clear and precise.
@@DrBecky .... do you prefer five hundred thousands subscribers or just half megasubscriber? I don't know... five hundred thousand of something sounds like so much more than half something (even if that something is a megasomething). Psychology vs math I guess.
@@adb012 She's a physicist. In physics we like clean units. You don't say five hundred thousand parsecs, you say 0.5 megaparsecs. Or 0.5 Mpc for short. Now we just have to figure out the symbol for subscriber. Can't be just "s", that's already seconds. Maybe "sb" is still free? So 0.5 Msb? If you insist of psychological effect, then let's go for 500 kilosubscibers. Or 500 ksb. I do however prefer 0.5 Msb, it just looks cleaner.
Congrats on reaching 500K subs Dr. Becky! The DART mission was an astonishing success! Looking forward to the info about the other parameters that you eluded to in this video! 👍👍💖💖
This is so exciting! I've been following this mission ever since you announced it at the beginning of the year. Along with the JWST telescope coming online. I love your videos, it's rekindled my love for astronomy. Thanks for the wonderful videos!
I'm astonished that the change in orbital period was that much when pre-impact estimates I heard were in the 10 minute range. Looks like it's very effective on apparent rubber piles like that asteroid. Congratulations on reaching half a million subscribers, Dr. Becky! 🎉 It felt not that long ago when I found you at around 100K and you've quintupled it since. Keep up the quality and fun content.
Welcome back!! 🙂 Yes, a huge success.. gives us a rough ballpark for something later in the future... Counting down the days till your book arrives.. 😎
I think the fact that we managed to change the orbit by ~30 mins does show that with enough warning we could send enough DARTs to save the planet. So long as we are sensible and don't break apart the target and just change its directory we could make enough affect. The fact it was 30x more affected than they were predicting shows this was a huge success. Well done DART Team.
The 73s is the min change we could detect from Earth, the estimate was to change the orbit time by 10min. "Only" 3x as much, but still great achievment.
@@CandC68 Astroid compositions vary. Some are essentially loose gravel held together by gravity. We do not have a deep understanding of the composition models and the associated collision physics, and it is impossible to test an analog on earth. Hence, we needed this test to increase understanding.
@@aemrt5745 I recall people asking on the first lunar landing, wondering if the lander and astronauts would sink into thick moon dust. We didn't have all the tools we have today. B-) With DART, did anyone think the asteroid was a loosely held collection of dust? Would DART simply fly through it? Nah. I think they had a good idea that it was mostly a solid. I don't think the trajectory planners were the only bright ones on the project. They had a pretty good idea what they were shooting at.
Dear Dr. Becky, I'm your newest fan! I teach science to 7th and 8th graders, and I've just introduced them to you via this video. You are remarkable in so many ways - simultaneously informative, clear, interesting and entertaining!! We're located in a university town (Ann Arbor) and the kids can be pretty picky about which science video presentations they find educational and which they find irritating, and they loved yours! I'm looking forward to showing more!. Also, they're interested in Brilliant, which I'm going to check out. Finally, I SO appreciate the Alexis reference in the bloopers! Thank you!
Still cannot believe we managed to throw an asteroid off course by 30 minutes. That's absolutely huge and will definitely come in handy if and/or when an asteroid actually does head our way. Cheers, and congrats on 500k!
Love your videos Dr B, such clear explanations. As you picked up after & before in the bloopers, may I suggest saying "one fewer thing" in preference to "one less thing"? Well you did mention your perfectionism... sorry, I'll get my coat. Px
When science. engineering and math is applied properly by professionals that are the best in their field we as a species can achieve amazing things, even great bloopers!
To add to all this, I was a little kid watching for Sputnik and Telstar, then the manned missions, then the Moon missions, then the shuttle, and the ISS and all the probes to the outer planets...not to mention the space-born telescopes. What a wonderful time to be alive.
Awesome video for an awesome mission! I assume they'll also learn more about the makeup of Didymos since they expected a much smaller effect (maybe it's mass is less than expected or it is made up of other layers of different densities?)
Her point was to calculate an asteroid's final velocity (not delta) after the collision if you know its energy before the collision, and you know how much you can transfer. You only have to "solve for v", which is what she did, and then plug in the final energy of the asteroid. All that "delta e", "delta v" talk is just confusing and misleading. Of course, that formula isn't going to help unless you do the extremely difficult task of calculating an asteroids total kinetic energy just by looking at it. As well as do models of the impact to estimate and optimize the energy transfer.
@@Olivaw4254 Hey, that’s exactly right! You essentially just computed the derivative, which gives the linear approximation of the change in kinetic energy :)
Your explanation of this experiment and its results is brilliant. We need people with your skills to explain in everyday language why some scientific experiments are so important and why some scientists and engineers get so excited doing these experiments.
Awesome news, keep the great work! Just one dumb question since I don't see it in the comments, is the formula at 7:48 correct? I feel like exponents do not work like that 😅
Yea i think it's gotta be 0.5*M*(Vf^2 - Vi^2). Now that's different from 0.5*M*(Vf - Vi)^2. M being the mass of the asteroid, Vf and Vi being the Final and initial velocities of the asteriod. Dr. probably overlooked it coz i bet she'd know this for a fact.
A huge win, indeed, and thank you, Dr.Becky. Significant win for all earthlings, defense of Planet Earth from Astroids or space debris. Long live STEM!
I've been waiting for this moment practically my whole life... when humanity finally has the ability to save itself from an astronomical catastrophe... TAKE THAT NASA BUDGET CRITICS !
Question: That was a stable two body system and now it has changed, has the loss of mass and the change of the orbit of the smaller body, changed the flight plan of the larger body? is anybody checking to see if we changed that too? I understand that that wasn't the experiment but is that an possible unintended consequence ?
Thanks Dr Becky for your ever-so-clear examination of the DART impact results 👍 Looks like we could dodge the bullet should one ever come our way. For completeness, I would love to hear your take on whether the larger shrapnel in the debris cloud could still pose a threat even when the big'un passes us safely by. Again, thanks for this ... and all your videos.
It amazes me that humans were able to send a 'projectile' and hit a tiny rock orbiting another small rock floating through space thousands of miles away...
I wonder if the point of impact makes any difference? Striking closer to the center of mass of the asteroid obviously mostly affects its speed but if the impact is closer to the edge will rotation play any additional role of changing asteroid's trajectory? P.S. Thanks for all your content, Dr. Becky!
@@introprospector Why wouldn't they rotate? It takes less energy for a small body to rotate than for a large one. It would also he highly unusual for an object to have exactly zero angular momentum.
@@michaelsommers2356 I don't know. I just know about tidal forces, and that they're small in this case which seems like it'd mean the rotation from that would be small, right?
Dr Becky, there are some really basic classical mechanics at work here. Very reachable at high school level! The energy of the impactor is divided into three types: elastic momentum lost to scattering of debris, inelastic momentum added to the asteroid as (a) change in linear (orbital) momentum and (b) change in spin momentum of the object. That's very much like a rolling basketball hit by paintballs... it's spin and motion are both effected. The paint splatter is also a lost momentum term. So it's a VERY teachable HS lesson, and even could have some FUN (paintball?) experiments designed!
I learn a great deal from your videos. You have an infectious love for your work that I find so great. I'm a layman when it comes to astrophysics, but you make it very comprehensible.
Dr. Becky, if you want to react to another Stargate episode, I suggest the one where they deal with an asteroid that will doom the Earth. It is called "Fail Safe" and it is episode 17 of the 5th season.
Been waiting on this for a while (ok, not THAT long in astrometrical time!) - seen a few others that had a title suggetsing they'd be explaining it, but I wanted to first watch someone I trusted to actually tell me what happened, the repurcussions, etc., accurately and in terms I could understand. Not disappointed!
I actually kind of teared up when I read about how much of a change DART made on the orbit. Not that I'm worried about a killer asteroid (the likelihood any of us will be affected by one is very slim), but I worry about those in the future. It's a great relief that we can say the threat of asteroids is diminished, all things holding equal.
It's actually not so much about energy, but about momentum transfer. (Actually, the orbital energy of that asteroid decreased by the collision. The superfluous energy was transformed into heat, and breaking pieces off.)
Well, if it can be managed, the best "momentum transfer" would happen were the rocket to bounce off the asteroid. You would have twice the momentum transfer as you would get over it just disintegrating. This woman is a bit silly when they uses energy when the important thing is momentum. Perhaps she was a affirmation action hire.
Wonderful and excellent! It'll be interesting to find out how all the collision data will affect current thinking. Will we see the rings formed by the dust cloud, and how long will it be until the whole thing settles back down? It'll be fascinating to learn just how much mass Didymos will have cast away to space and how much will be drawn to Dimorphos. I'm curious about how much of a change the central body Dimorphos will experience in its solar orbit because of the 'gravity tractor' type of effect. I see that there is a new simulation about how the Earths moon was formed, I wonder if this 'real world' test will be able to expand the understanding of the early formation of planets. So exciting!! Congratulations on half a million subscribers!!!
Based on the images of the plume outflow from the accompanying cube sat, and the observation of the particulate size by DART itself prior to impact, I'm not surprised that the deflection was larger than expected as the absence of small particles like seen in other "rubble pile asteroids like Bennu or Ryugu it seems only big chunks of material fall back to the surface and the outflow plume from the glimpses up close was crazy complex with material erupting/streaming out from deep within the asteroid.
There's probably a lot of opportunity for more mass loss than expected here. First you shake up a rubble pile with an impact, then an orbital period that was probably synchronous with the object's rotation is shortened, meaning that those periods are now out of sync. Given the oblong shape of Dimorphos, the easiest way for those to be resynchronized is probably some sort of further rearrangement of material.
I suppose the next test will involve some ion thruster engine, providing small thrust over a Very Long Time, as a comparison. The longer we we have about an incoming asteroid, the more tools we can use to change the path.
This is a great result! I know there's more data and observations to accumulate, but this looks really promising! While I'm all but certain an extinction-asteroid is not going to happen during my lifetime, it's great that we might have this ready to go, just like you said at the end.
Dr. Becky, I'm reading your book now ~ it's so good! You explain concepts so well, and I love learning the history of how we've come to learn about our universe. Great, great job❤👏👏👏👏👏👏👏👏👏
Thanks for the explanation and calculation formula (waaay above my math skills, but it was fascinating to see what it would be). Someone told me an article indicated it failed, so I instantly said let's see what Dr Becky says. I trust your information!! Soo cool how much the orbit changed, this is very good news. 👏👏👏 I loved Schitt's Creek too, they would be thrilled you mentioned them. 😀
Hi Dr Becky, a couple of questions: 1. Given that the collision was more or less head on, does this mean that the launch was made westward, against the rotation of the Earth, requiring a greater energy requirement from the rocket than an eastward launch? 2. How do you think the outcomes would compare between the collision technique used by DART vs other techniques, such as parking next to the asteroid to make a tiny gravitational pull over a long time or placing a solar powered plasma rocket on the surface to give it a tiny push over a long period of time?
Great vid and easy to understand. Hipparchus discovered Precession around 170BC. The Mayans understood Precessin, Solstic points and the movement of the Sun through the galactic Equator. 2012 is important to them. 1. What is the time frame of the Solstic points and the Sun moving through the galactic equator, up to down in years. Precession moves 0.014 degrees per day. What is the degree movement of Solstic point and Sun crossing the Galactic equator? How did Hipparchus and the Mayans detect such a minute celestial movement?
Becky, It is always a pleasure to watch your videos. You always do an amazing job of explaining things and it is clear that doing so is a passion for you. Best James
This is so frikkin cool. I can't believe the intellect it takes to a: do all the crazy math I'll never understand, b: builds the equipment for the mission, c: making it actually work. I feel like an ape....
So are they still tidally locked after it’s orbital slow down? Would it’s tidal drag slow down the larger asteroid’s rotation? Or if it’s rotation remained constant, will it spin back up its orbit over time??
Forgive my ignorance @Dr. Becky, I have two questions... 1> Given how much more significant the shift in orbit turned out to be, is there not a risk we may have overdone it? i.e. The resultant force on Dimorphos might have cracked the egg so to speak. And 2> I believe that if our moon changed orbit, this would affect the seasons and tides on Earth. Is it possible that the gravitational balance between the two asteroids could impact on didymos in some way too. i.e. In this case, a change of orbit/speed, stability etc.
I love your presentations , you’re so bubbly and enthusiastic. Just curious, have you seen the latest Astrum video on black holes, would love to hear your thoughts on the video. Keep up the great work Dr. Becky ❤️🤗
I've listened to about a half dozen people explaining this, and Dr B is the only one who hasn't fallen into jargon. I actually understood your entire explanation.
same here - the math part i was lost on - but i knew exactly what she was saying
The trouble is none of what she said is true. 1) It is a fact of mathematics that the precision of the total calculation can NEVER be greater than the precision of the least precise measured factor or variable.
2) They will never have enough data about the size shape and density of the target asteroid to make useful calculations ever. Any measurement of the mass and the velocity of the ejected dust will be at best what we called in engineering a WAG - a Wild Ass Guess. This means the best answer they can possibly arrive at is also a WAG..
3) They could have made that WAG 5-30 minutes after they had they new orbital time or they can never make it at all. There will never be any better data to be had.
4) The next asteroid will be of a completely different composition and density so there will be almost zero transferability of this data to future tests. You would have to run 500 of these tests on different types of asteroids to get anything vaguely useful. .
5) The only real reason for the delay is that presenting the calculations immediately is not impressive enough to politicians to justify the money spent and for future tests. They have to make it look hard.
6) She buzzed right past the most interesting point. Hitting the asteroid did NOT slow it down. It speeded it up! They must have hit it while it was moving away from them. Why would they do that? If you are trying to deflect or stop something you hit it either head on or at an angle on the front as it is coming at you.
@@johnbreitmeier3268 no. None of what YOU said is true. They have plenty of instruments and data to make very precise measurements and predictions. There's nothing WAG about this, it's good science.
And re: point 6, the orbit was reduced which corresponds to a reduction in orbital velocity.
@@TimHollingsworth80 Timmy My orbital physics is rusty so you MAY be right on 6) BUT I am absolutely right on the WAG. You did not listen closely. She TOLD you plainly it was a WAG. Things they have zero way of knowing: 1) What the asteroid was make of. If you looked at the picture it is a loosely bound ball of random space junk. There is no way of knowing the density, what it was even mostly made of. 2) There is no way of knowing if there were internal voids or how many. This affects the mass greatly. 3) No way to accurately guess even the volume of a lumpy mass they saw one side of. 4) Absolutely zero way to even wildly guess how much stuff of what mass was ejected at what speed in what directions to be able to reduce that to a single resultant recoil vector for a calculation. If 1% of the total mass of the asteroid was ejected then that is negligible and can be discounted. If it is > that 25% certainly not. Do they have a clue. They do not seem to.
You can very accurately measure a few things but if you cannot precisely measure even one variable the precision of the answer is reduced to the precision of that variable. All the rest of the expensive precise measurements were wasted and useless. People like you were not rained to understand this. You watch the shiny object and go OOOOH! You have a boatload of WAGS going into this calculation and all that can possibly come out is a WAG. If you know the beginning and ending mass of the asteroid to a guess of one significant figure (and that would be a stroke of luck) you just get a guess at one significant figure out. Look up what a significant figure is.
I was a "top government scientist" and engineer for years. I know the dance steps.
Nothing wrong with jargon.
It's sad that the media hasn't made a bigger deal out of this. This team has provided a proof of concept that could potentially save our entire civilization, along with every other living thing on the planet. It is a huge step toward ensuring the long term survival of our species. They have my utmost respect and most sincere gratitude.
To eradicate all life it would take enough impact energy to evaporate the oceans and melt all of earths crust, and even then life might survive frozen inside orbital debris, waiting for the crust to solidify and the oceans to pour from the heavens, that could survive reentry if it happens to aerobreak in the right way and life would be back on earth and might conquer it anew.
Who knows, maybe that even happened already, we don't know.
@@jannikheidemann3805 I'm not sure I'm seeing your point...
@@jannikheidemann3805 But to destroy our civilization, or have an impact that could destroy the economy of a nation state, it would take much much less than you describe.
And Cop27 starts this week, and still, some argue that there is no issue.
I agree it’s hard that more isn’t still out there from common media, but the truth is the US had the most miserable mid term election fight in my lifetime, and a War that could make the worry about an asteroid hitting an Earth burned by a nuclear snowball fight.
It's been a great week for DART news!
Also, congrats on 500K Becky, you inspire us all!
And here’s to the soon to come 1 million more!
@@mbunds Amen 🙏
I can't imagine the person sitting there to observe the time change only to find out that it was 30x greater than expected. They probably did a double take, cleaned their glasses, bumped their monitor, ran whatever associated test/program there was again several times, and then just sat there absolutely astounded.
Nah, I bet that was in the expected range.
The main reason we couldn't have a concrete estimation was due to missing data about the composition of the asteroid and it being new data about such a mission as a whole.
I can't imagine, with all the computational power available to the team, how they were incorrect but such an astronomical margin. lol
i genuinely think they way underestimate so that they are more likely to meet the goal. similar to how they underestimate the service life of the mars rovers & such. to be fair to NASA this basically what i do when i set goals for my life LMAO
@@blurfs3763 power but also data
A lot of the explanation is we do not understand asteroid composition and the associated impact physics in depth.
What impressed me most was the accuracy of the bombing of dimorphos. Hitting something 7 million miles away that is a moving target about the size of a football stadium is a lot of math. Orbital mechanics and rocket science. backed up by a lot of electronics, optics and visionaries.
So why can't they do the same in Ukraine against the Russians?
Yep. Kudos to the Orbital Mechanics team. It is pretty amazing.
It's not that hard, to be honest, the tracking software is basic as shit, and overlay that is in camera software, and boom you hand that over to engineers
@@tonyw8001 I'm not privy to the specifics, myself, but I bet this is pretty accurate. Computers make the hard calcs easier, and with the right programs, much, much easier.
and yet they can't shoot a nuclear missile out of the freakin sky . . .
The bloopers always has me smile. The iceing on the cake. Thanks Dr. Becky, you're an excellent science communicator. 👍👍
A great combination of being informative and funny.
The Alexis impersonation at the end was hilarious.
The blooper is giving Cardi B "OMG What is that?" Energy and I love it 🤣
Congratulations on 500k subscribers. I've learned so much form your videos. You're the best ❤️
Thank you 🥰
Love your videos and what an exciting update! One little math correction on this one: The change in kinetic energy of the asteroid is 1/2m(vf^2 -vi^2), which is not the same as 1/2m(vf-vi)^2 or 1/2m(delta v)^2 as you wrote. For fun, I was planning on having my physics students calculate how many Joules of (negative) work was done on Dimorphos by the impact and compare it to the kinetic energy of DART before impact. We can use Kepler's laws to derive the initial and final velocities given the orbital period and semimajor axes before and after but if you happen to know the initial and final velocities of Dimorphos, please list them! We'd assume a negligible change in mass of the asteroid. Thanks!
I came here to say exactly the same thing. My Engineering soul screamed a bit when I saw that. Bad Dr Becky. :D Don't worry we still think you are awesome.
Yep, it leaps right out, doesn't it?
Energy is not conserved in inelastic collisions like this, but momentum always is. Using simplifying assumptions for the ejecta plume properties, you can calculate the delta v very simply.
@@pemoreland *mechanical energy is not conserved, the lost energy is transformed into material/heat/light/sound energy
And here is the *"**#Comets**"* I was L00King for 🧐
Fascinating. The September issue of Sky and Telescope has an excellent article explaining the impact physics. I am surprised they had that large of a velocity change. Well, that's why we always test!
From Scott Manley's analysis of the images showing the typical particle size on Didymos i.e. the lack of anything smaller than large boulders and the early images of the accompanying cube sat of the out flow response from the asteroid it starts to make a lot more sense after all the plume outflows were crazy complex with eruptions of material emerging from the depths of the asteroid all over its surface. I would bet most of that ejecta escaped into space and thus pretty much all contributed to changes in Didymos's orbital angular momentum.
This was the best breakdown of the DART mission I've seen. Thanks!
Yes indeed
I'm only certain I've gotten the real scoop when I've heard your take on the subject, you're so transparently telling it exactly as it is the best you can, which is crystal-clear and precise.
Congrats on 0.5 megasubscribers, Becky! You really deserve every single one and many, many more.
Also great news on DART's stellar success.
Megasubscribers 😂 I love that
@@DrBecky .... do you prefer five hundred thousands subscribers or just half megasubscriber? I don't know... five hundred thousand of something sounds like so much more than half something (even if that something is a megasomething). Psychology vs math I guess.
@@DrBecky I subscribed
Love your explanations 👌
👏👏👏
I'm a semi-megasubscriber. Hemi-megasubscriber? Demi-megasubscriber?
@@adb012 She's a physicist. In physics we like clean units. You don't say five hundred thousand parsecs, you say 0.5 megaparsecs. Or 0.5 Mpc for short. Now we just have to figure out the symbol for subscriber. Can't be just "s", that's already seconds. Maybe "sb" is still free? So 0.5 Msb? If you insist of psychological effect, then let's go for 500 kilosubscibers. Or 500 ksb. I do however prefer 0.5 Msb, it just looks cleaner.
Congrats on reaching 500K subs Dr. Becky! The DART mission was an astonishing success! Looking forward to the info about the other parameters that you eluded to in this video! 👍👍💖💖
Excellent explanation. I can see you working on the next Cosmos series!
Sounds exciting with a lot of work and involving a lot of people.
This is absolutely nuts ..! PS nice book in the background ;)
This is so exciting! I've been following this mission ever since you announced it at the beginning of the year. Along with the JWST telescope coming online. I love your videos, it's rekindled my love for astronomy. Thanks for the wonderful videos!
I am so happy to see you are back. I was waiting for your video to understand what the results of DART were.
I'm astonished that the change in orbital period was that much when pre-impact estimates I heard were in the 10 minute range. Looks like it's very effective on apparent rubber piles like that asteroid.
Congratulations on reaching half a million subscribers, Dr. Becky! 🎉 It felt not that long ago when I found you at around 100K and you've quintupled it since. Keep up the quality and fun content.
*rubble pile
@@ktrimbach5771 *Gomer Pyle 😆
@@ktrimbach5771 Didn't see that, thanks
Autocorrect needs improvement
@@I.amthatrealJuan With the amount of stuff thrown backwards, perhaps the autocorrect has got the better description. 😉
Dear Becky thank you for the video, really interesting, I’ve been waiting to hear this, really really thank you 🙏👍
Dr Becky,
Props for easy explanations to us mortals.
Keep on keeping it understandable and fun!
🙂
Welcome back!! 🙂
Yes, a huge success.. gives us a rough ballpark for something later in the future...
Counting down the days till your book arrives.. 😎
Ty Dr Becky, out of all the coverage I’ve seen on this I knew yours would be the most useful and succinct and it certainly was
Good summary.
Now we just need to build & warehouse a couple of these (or bigger) so we can deflect an ELE sized object.
Agree
The biggest draw back is the funding 🥺
The change in kinetic energy is: ∆ke=m*v*dv+m*dv^2/2. (constant mass) . To be more accurate. Now if dv
I think the fact that we managed to change the orbit by ~30 mins does show that with enough warning we could send enough DARTs to save the planet. So long as we are sensible and don't break apart the target and just change its directory we could make enough affect. The fact it was 30x more affected than they were predicting shows this was a huge success. Well done DART Team.
The 73s is the min change we could detect from Earth, the estimate was to change the orbit time by 10min. "Only" 3x as much, but still great achievment.
Relying on us to be sensible is not something I do. The 30x result shows to me, that we didn't know enough when planning and estimating.
In 2 weeks NATO will have a meeting considering a premtive nuke on Russia
@@CandC68 Astroid compositions vary. Some are essentially loose gravel held together by gravity. We do not have a deep understanding of the composition models and the associated collision physics, and it is impossible to test an analog on earth.
Hence, we needed this test to increase understanding.
@@aemrt5745 I recall people asking on the first lunar landing, wondering if the lander and astronauts would sink into thick moon dust. We didn't have all the tools we have today. B-)
With DART, did anyone think the asteroid was a loosely held collection of dust? Would DART simply fly through it? Nah. I think they had a good idea that it was mostly a solid. I don't think the trajectory planners were the only bright ones on the project. They had a pretty good idea what they were shooting at.
Dear Dr. Becky, I'm your newest fan! I teach science to 7th and 8th graders, and I've just introduced them to you via this video. You are remarkable in so many ways - simultaneously informative, clear, interesting and entertaining!! We're located in a university town (Ann Arbor) and the kids can be pretty picky about which science video presentations they find educational and which they find irritating, and they loved yours! I'm looking forward to showing more!. Also, they're interested in Brilliant, which I'm going to check out. Finally, I SO appreciate the Alexis reference in the bloopers! Thank you!
Glad you scientists are doing it, I can’t imagine how to figure out the mass in the plume…
Excellent summary. Rich content. Thanks.
Still cannot believe we managed to throw an asteroid off course by 30 minutes. That's absolutely huge and will definitely come in handy if and/or when an asteroid actually does head our way. Cheers, and congrats on 500k!
How do ever really know we did or if it's just more lies from a government agency?
Hurray, great news! Thank you, I really needed something to be happy about. ❤️❤️
I can't wait for Future Asteroid Redirection Tests.
I see what you did there. 😂
Love your videos Dr B, such clear explanations.
As you picked up after & before in the bloopers, may I suggest saying "one fewer thing" in preference to "one less thing"? Well you did mention your perfectionism... sorry, I'll get my coat.
Px
When science. engineering and math is applied properly by professionals that are the best in their field we as a species can achieve amazing things, even great bloopers!
To add to all this, I was a little kid watching for Sputnik and Telstar, then the manned missions, then the Moon missions, then the shuttle, and the ISS and all the probes to the outer planets...not to mention the space-born telescopes. What a wonderful time to be alive.
Indeed. Space travel is incredible.
Awesome video for an awesome mission! I assume they'll also learn more about the makeup of Didymos since they expected a much smaller effect (maybe it's mass is less than expected or it is made up of other layers of different densities?)
I love the product placement on the shelf over your left shoulder!
Nice video, but I think there’s a little bit of a math oopsie at 7:58. Delta(KE) = 1/2 m v_1^2 - 1/2 m v_0^2 =/= 1/2 m (Delta v)^2
I thought the same.
I'd say it's Δ(KE) = 1/2*m*(v1 + v0)*(v1 - v0) which is (in case of v1 ≈ v0 = v) 1/2*m*(v + v)*Δv = m*v*Δv. So Δv = Δ(KE)/(m*v).
Interesting to see how many comments were made before someone pointed out the mistake.
Her point was to calculate an asteroid's final velocity (not delta) after the collision if you know its energy before the collision, and you know how much you can transfer. You only have to "solve for v", which is what she did, and then plug in the final energy of the asteroid. All that "delta e", "delta v" talk is just confusing and misleading.
Of course, that formula isn't going to help unless you do the extremely difficult task of calculating an asteroids total kinetic energy just by looking at it. As well as do models of the impact to estimate and optimize the energy transfer.
@@Olivaw4254 Hey, that’s exactly right! You essentially just computed the derivative, which gives the linear approximation of the change in kinetic energy :)
That was so well explained and really informative. Brilliant video.
I was insanely curious about how much time would be needed to detect a change!
They said it would take a couple of months. Then a few days later they came out with all these observations.
This is so important for the future.
Is the ejecta expected to settle back onto the bodies or mostly stream off behind them? Will this comet appearance be short-lived?
Your explanation of this experiment and its results is brilliant. We need people with your skills to explain in everyday language why some scientific experiments are so important and why some scientists and engineers get so excited doing these experiments.
We have ONE: Dr Becky. We need more with these more-than-adequate skills.
Awesome news, keep the great work! Just one dumb question since I don't see it in the comments, is the formula at 7:48 correct? I feel like exponents do not work like that 😅
Yea i think it's gotta be 0.5*M*(Vf^2 - Vi^2). Now that's different from 0.5*M*(Vf - Vi)^2. M being the mass of the asteroid, Vf and Vi being the Final and initial velocities of the asteriod. Dr. probably overlooked it coz i bet she'd know this for a fact.
Yeah I cringed too... actually, the correct first order approximation would be m*v*Delta(v).
The work has just begun. This is the first step🎉😊
A huge win, indeed, and thank you, Dr.Becky. Significant win for all earthlings, defense of Planet Earth from Astroids or space debris. Long live STEM!
I am more worried by the Borg Cube.
@@robertpearce8394 Thi is real science, not science fiction!
@@lakehart And that was a joke, take it like one
Dr. Becky, just bought my first telescope always enjoy your informative show!
I've been waiting for this moment practically my whole life... when humanity finally has the ability to save itself from an astronomical catastrophe... TAKE THAT NASA BUDGET CRITICS !
Yeah, I'm honestly pretty glad that we were able to cross at least _one_ doomsday scenario out of the list!
thanks for this informative talk!
Question: That was a stable two body system and now it has changed, has the loss of mass and the change of the orbit of the smaller body, changed the flight plan of the larger body? is anybody checking to see if we changed that too? I understand that that wasn't the experiment but is that an possible unintended consequence ?
Of course it's expected to change both asteroids' trajectories.
Thanks Dr Becky for your ever-so-clear examination of the DART impact results 👍 Looks like we could dodge the bullet should one ever come our way. For completeness, I would love to hear your take on whether the larger shrapnel in the debris cloud could still pose a threat even when the big'un passes us safely by. Again, thanks for this ... and all your videos.
It amazes me that humans were able to send a 'projectile' and hit a tiny rock orbiting another small rock floating through space thousands of miles away...
It's not thousands.
@@passerby4507 seven million miles... but I can write it as 7000 thousands and still be right 😅
The DART Mission was very exciting and successful, and I really like your colour choices of the room you filmed in. 😀
I wonder if the point of impact makes any difference? Striking closer to the center of mass of the asteroid obviously mostly affects its speed but if the impact is closer to the edge will rotation play any additional role of changing asteroid's trajectory?
P.S. Thanks for all your content, Dr. Becky!
Any energy that goes into a change of rotation doesn't go into changing the trajectory so I think fine tuning the target is important.
Do small systems like this rotate? There shouldn't be any tidal locking I wouldn't think
@@introprospector Why wouldn't they rotate? It takes less energy for a small body to rotate than for a large one. It would also he highly unusual for an object to have exactly zero angular momentum.
@@michaelsommers2356 I don't know. I just know about tidal forces, and that they're small in this case which seems like it'd mean the rotation from that would be small, right?
@@introprospector Tidal forces have nothing to do with why things rotate. It's all about angular momentum.
Dr Becky, there are some really basic classical mechanics at work here. Very reachable at high school level! The energy of the impactor is divided into three types: elastic momentum lost to scattering of debris, inelastic momentum added to the asteroid as (a) change in linear (orbital) momentum and (b) change in spin momentum of the object.
That's very much like a rolling basketball hit by paintballs... it's spin and motion are both effected.
The paint splatter is also a lost momentum term.
So it's a VERY teachable HS lesson, and even could have some FUN (paintball?) experiments designed!
I learn a great deal from your videos. You have an infectious love for your work that I find so great. I'm a layman when it comes to astrophysics, but you make it very comprehensible.
Thanks for the clear explanation!
Dr. Becky, if you want to react to another Stargate episode, I suggest the one where they deal with an asteroid that will doom the Earth. It is called "Fail Safe" and it is episode 17 of the 5th season.
Saved by the "Ass guard" 😂🤣😂🤣🤣
And here is the *"**#Comets**"* I was L00King for 🧐
Been waiting on this for a while (ok, not THAT long in astrometrical time!) - seen a few others that had a title suggetsing they'd be explaining it, but I wanted to first watch someone I trusted to actually tell me what happened, the repurcussions, etc., accurately and in terms I could understand. Not disappointed!
Wonder if there will be any changes in either bodies due to the faster, lower orbit 🤷♂️ 🤙
And the reduced mass of the orbiting asteroid. Subtract the ejecta mass.
"After and Before" is charming and should be allowed by that perfectionist urge! Thank you Dr. Becky.
Nice to know we *might* not go the way of the dinosaurs.
Everybody knows the dinosaurs really died from smoking. 😂. A joke.
@@tyroberts2261 the dust clouds that killed off their food supply could be considered smoke. I think you're onto something =)
@@tyroberts2261 LOL, love Gary Larson's cartoon about that!
well, if we keep electing dinosaurs for office...
We will destroy ourselves,
Don't worry 😉
Yes! An Alexis callout. Loved her character, and Schitt's Creek overall was a joy.
Subtle placement of your new book there, Becky lol 😆
I actually kind of teared up when I read about how much of a change DART made on the orbit. Not that I'm worried about a killer asteroid (the likelihood any of us will be affected by one is very slim), but I worry about those in the future. It's a great relief that we can say the threat of asteroids is diminished, all things holding equal.
It's actually not so much about energy, but about momentum transfer. (Actually, the orbital energy of that asteroid decreased by the collision. The superfluous energy was transformed into heat, and breaking pieces off.)
Well, if it can be managed, the best "momentum transfer" would happen were the rocket to bounce off the asteroid. You would have twice the momentum transfer as you would get over it just disintegrating.
This woman is a bit silly when they uses energy when the important thing is momentum. Perhaps she was a affirmation action hire.
So glad to have you back. I hope your time off was relaxing or, at least, enjoyable. 😎🤓
.ﾟ.*･｡☄️ﾟ.*･｡ﾟ Smashed it 👍🏼, another great show Dr Becky ✯. Thank you ♡ ❥`๑)
As usual, a nice cogent explanation Dr. Becky... thank you...
An excellent explanation which avoided any mention of the Third Law brilliantly.
Wish I had her as a teacher at school. Her energy and clear explanations make the subjects so much more interesting 👍😀
Take further comfort knowing that perfectionism cannot be perfectly cured, but only managed, imperfectly.
Absolutely awesome video DrBecky....you are a great communicator...
and hope you have a great success with your book...
Watching your videos makes me think how much Patrick Moore would have marvelled at how far we have come.
Wonderful and excellent!
It'll be interesting to find out how all the collision data will affect current thinking.
Will we see the rings formed by the dust cloud, and how long will it be until the whole thing settles back down?
It'll be fascinating to learn just how much mass Didymos will have cast away to space and how much will be drawn to Dimorphos.
I'm curious about how much of a change the central body Dimorphos will experience in its solar orbit because of the 'gravity tractor' type of effect.
I see that there is a new simulation about how the Earths moon was formed, I wonder if this 'real world' test will be able to expand the understanding of the early formation of planets.
So exciting!!
Congratulations on half a million subscribers!!!
As the data is analyzed, there will be awesome papers and articles written!
Based on the images of the plume outflow from the accompanying cube sat, and the observation of the particulate size by DART itself prior to impact, I'm not surprised that the deflection was larger than expected as the absence of small particles like seen in other "rubble pile asteroids like Bennu or Ryugu it seems only big chunks of material fall back to the surface and the outflow plume from the glimpses up close was crazy complex with material erupting/streaming out from deep within the asteroid.
There's probably a lot of opportunity for more mass loss than expected here. First you shake up a rubble pile with an impact, then an orbital period that was probably synchronous with the object's rotation is shortened, meaning that those periods are now out of sync. Given the oblong shape of Dimorphos, the easiest way for those to be resynchronized is probably some sort of further rearrangement of material.
Love your clarity!
Thank you NASA/USA 🇺🇸
I suppose the next test will involve some ion thruster engine, providing small thrust over a Very Long Time, as a comparison.
The longer we we have about an incoming asteroid, the more tools we can use to change the path.
I watched 2 other videos on this matter and was left thinking, "so is that a good thing?" Then here comes Dr. Becky explaining it perfectly
This is a great result! I know there's more data and observations to accumulate, but this looks really promising!
While I'm all but certain an extinction-asteroid is not going to happen during my lifetime, it's great that we might have this ready to go, just like you said at the end.
Thank you Dr Becky.... It is easy for me to get carried away.
Dr. Becky, I'm reading your book now ~ it's so good! You explain concepts so well, and I love learning the history of how we've come to learn about our universe. Great, great job❤👏👏👏👏👏👏👏👏👏
so clearly explained, thanks! also, I love the accent!
Thanks for the explanation and calculation formula (waaay above my math skills, but it was fascinating to see what it would be). Someone told me an article indicated it failed, so I instantly said let's see what Dr Becky says. I trust your information!! Soo cool how much the orbit changed, this is very good news. 👏👏👏
I loved Schitt's Creek too, they would be thrilled you mentioned them. 😀
my second video of yours and i love it!
thanks and keep up
wish you well
Hi Dr Becky, a couple of questions: 1. Given that the collision was more or less head on, does this mean that the launch was made westward, against the rotation of the Earth, requiring a greater energy requirement from the rocket than an eastward launch? 2. How do you think the outcomes would compare between the collision technique used by DART vs other techniques, such as parking next to the asteroid to make a tiny gravitational pull over a long time or placing a solar powered plasma rocket on the surface to give it a tiny push over a long period of time?
Best explanation I've heard yet, I'll forward this to the physics teachers in my department, thank you.
Great vid and easy to understand. Hipparchus discovered Precession around 170BC. The Mayans understood Precessin, Solstic points and the movement of the Sun through the galactic Equator. 2012 is important to them. 1. What is the time frame of the Solstic points and the Sun moving through the galactic equator, up to down in years. Precession moves 0.014 degrees per day. What is the degree movement of Solstic point and Sun crossing the Galactic equator?
How did Hipparchus and the Mayans detect such a minute celestial movement?
Becky, It is always a pleasure to watch your videos. You always do an amazing job of explaining things and it is clear that doing so is a passion for you. Best James
I hope they literally call the follow up, the Follow-up Asteroid Redirection Test.
This is so frikkin cool. I can't believe the intellect it takes to a: do all the crazy math I'll never understand, b: builds the equipment for the mission, c: making it actually work. I feel like an ape....
another question is did the change in orbit of dimorphos affect didymos' orbit and how?
So are they still tidally locked after it’s orbital slow down? Would it’s tidal drag slow down the larger asteroid’s rotation? Or if it’s rotation remained constant, will it spin back up its orbit over time??
Forgive my ignorance @Dr. Becky, I have two questions... 1> Given how much more significant the shift in orbit turned out to be, is there not a risk we may have overdone it? i.e. The resultant force on Dimorphos might have cracked the egg so to speak. And 2> I believe that if our moon changed orbit, this would affect the seasons and tides on Earth. Is it possible that the gravitational balance between the two asteroids could impact on didymos in some way too. i.e. In this case, a change of orbit/speed, stability etc.
I love your presentations , you’re so bubbly and enthusiastic.
Just curious, have you seen the latest Astrum video on black holes, would love to hear your thoughts on the video.
Keep up the great work Dr. Becky ❤️🤗
You're a great teacher!
You are totally awesome. No one better than you. I appreciate so much what you produce. May God be with you and your family. Live long and prosper 🖖
Excited seeing all the cool space stuff in the news.
"David..." Excellent 👍