Neil deGrasse Tyson Explains the Rocket Equation
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- čas přidán 8. 02. 2021
- You’ve seen the rockets blast off into space, but, have you ever wondered the science behind the launch? On this StarTalk explainer, Neil deGrasse Tyson and comic co-host Chuck Nice are exploring the rocket equation, space travel, and more.
To start, we discuss why the application of mathematics adds to the theory of a simulation universe. Then, Neil tells us about the problem with space travel: fuel. You have to have enough fuel to get where you want to go, but, the fuel you have to carry to get to your destination adds weight, which means you need more fuel. And so on, and so on. So, what do you do?
We explore how the miniaturization of electronics helped rockets shed weight. Discover more about SpaceX’s reusable rockets. All that, plus, Neil shares some of the experiments he used to do in his car to save gas.
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Science meets pop culture on StarTalk! Astrophysicist & Hayden Planetarium director Neil deGrasse Tyson, his comic co-hosts, guest celebrities & scientists discuss astronomy, physics, and everything else about life in the universe. Keep Looking Up!
#StarTalk #NeildeGrasseTyson - Věda a technologie
“I didn’t feel safe doing this but it was for science” 😅
Basically every scientist ever lol
@@grandelDR I guess it's better than "Hold my beer."
NASA in a nutshell
😆 as a truck driver I have to disapprove of this message. Please don't.
@@TrickyClaw Basically every _teenager_ ever.
Neil: Have you ever wondered why...
Me: Most likely no, but please continue!
😂😂😂😂😂😂
"I didn't feel safe doing this, but it was for science."
~ Neil DeGrasse Tyson.
Greatest statement ever made of all humankind.
If he was doing it for science, he wouldn't be getting his explanation so wrong.
2:44 The happiness of learning science and mathematics.
My daily space dose.. SORTED 👍
daily?
methinks you may be a brit :)
Chuck: I wish NASA talks like that.
9:02 “talked” ... because Chuck speaks English really well.
@Ojas I see what you did there.
See, I'd have said it TWICE.
@Ojas Here's a glass of bear with ICE .
About 500 years from now, someone refuelling their spacecraft and "needing a candy" from the shop on an outstation on the moon is going to be looking at this video and saying look how Sir Neil DeGrasse Tyson and people of 21st century thought space fuel stops were a joke.
That would be hilarious hahaha.
and you think humanity can survive that long?
Plenty of oxygen and hydrogen on the moon.
Is Neil DeGrasse Tyson nighted?
I’ll be eating with them at monolith burger (the Mc ds of space).
“Did you also calculate how to draft trucks?” “I did that once.” “OH COME ON!” 😂😂😂
For Science 😂
Cc ccshow aaaaaa
Only Sir NDT can say that LOL! When you do what you love, you will never work again. Instead you will fool around dangerously ... for science!
Startalk just makes my evening better
Yes
ΔV = c*ln(Min/Mfin) , where Min is the initial mass and Mfin is the final mass, this is the Tsiolkovsky equation aka the rocket equation
@@HopDavid The exponential component of this equation is that fuel mass is an exponential function of the changes in velocity of the maneuvers you intend to make. Fuel mass is proportional to payload mass.
@@HopDavid Is this making you feel better about yourself?
@@kevinfitts9252 eggsacly...
What's c?
@@xdragon2k its the exit velocity
"The Rocket Equation: It´s a beautiful thing."~Chris Hadfield
Ofcourse I get that ad right before the video xD
mine started with neils ad then ended with chris' ad lol targeted advertising is starting to work!
"Now I need my fuel to get my fuel to get my fuel to get my stuff to the moon"
-Chuck
🐐 sh**
“Those of you still using internal combustion engines” thats him flexing his Tesla model X.
250 miles for 22 dollars on average isnt better than gas during a Republican presidency, you cant work on the car yourself because of expensive specialty tools and parts, diminishing range for about a decade until your battery wont hold a charge and needs to be replaced at a significant cost, and unless you only source energy from your own solar panel the electricity is still most likely produced using fossil fuels thereby negating any positive environmental impact. How is it a flex again?
Always there to fill the gaps in my knowledge 📕
@@HopDavid I'm currently writing a big project about the space race and the math/physics behind the development of the Rockets. Why do you say Neil explained it wrong?
And can you go from Newtons laws to get the rocket equation?
I love you guys! you make learning science fun amd easy to understand. Been watching a lot of your explainer zones.
Please dont draft off 18 wheelers, we know you're there, its dangerous.say yes to life.
You're*. But i agree with the sentiment.
Agreed... Stay safe...
Tailgating reduces reaction time calculate that next time you want to save a few bucks, but now I know how they estimate the outrageous gas mileage on New Cars...
@@steve-o6413 "Tailgating reduces reaction time". I think your words didn't come out right. I think you meant to say, tailgating reduces your room for error, that you need because of your reaction time.
Your reaction time depends on the capabilities of your nervous system, not whether you are tailgating or not.
You guys are hysterical and educational! Love you guys!
If someone had explained this to me 45 years ago the way you two just did, I'd have majored in Mathematics instead of switching to History after failing (three semesters of attempts) to understand the "why" of calculus. I appreciate you guys SO MUCH!
@@HopDavid I'm curious about what parts of the rocket equation he botched. care to tell?
@@HopDavid I see, very interesting stuff.
"completely" botched the rocket equation.. please, explain?I see you spamming this everywhere. Inform us of your thoughts that pertains to Dr Tyson "botching" the equation.
Yes I'm so glad to hear Neil talk about having a half full tank for better fuel economy... I thought I was the only one that did that...
You always explain in such an informative way, Dr. Tyson. I love how you love science so much. It’s obvious in all of your projects. I love science as much as I love art because I studied fine art in college. I would love to hear you explain fine art and contemporary art. That would help a lot of art students out because art has so many abstract questions like the questions of physics, like are we living in a simulation.
This episode should have been one hour long and have Q&A -_- Please do that! I still want to know mooooooooooore about rockets!
I don't know how much Chuck is just playing along, being an intentional sounding board for Neil, but I love the premise of their interaction: Neil helps Chuck see scientific concepts in an everyday way, and Chuck helps Neil see them in a humorous way.
This is where the hours playing kerbal space program finally kick in
Finally a thing that I can be proud with😂
Neil saying Mun at 4:24
"I didn't feel safe doing it, but it was for SCIENCE!"
Staging also lets you optimize your engine for the altitude range it's used in. Different engine bells work better at, say, sea level in Florida than at 80 or 100km in altitude. The less air pressure there is, the larger a bell is needed to extract the maximum energy from the rocket exhaust.
Cool of you to just drop a random interesting fact like this.
The animation on the water tower video was very helpful. why did you fire that guy?
You guys are hilarious 😂 😍 I'm never getting fed-up of Startalk
Random Peoples: "Why would SpaceX put a car into space, thats makes no sense"
Me Internally: 'But...Conclusively... You KnOw weve been to space now...'
Musk changed standard dead weight for his car. It could be just blocks of weight. Boring
Very True. Stuff..
wasn't that a "test" payload? and he used it to advertise the Tesla - 2 birds one stone? probably claimed advertising costs as tax rebate!!
@@alwysrite yes I think it was a test but I have to look into it
@@alwysrite he is clever. ;)
Love this channel so freaking much!
Man, I love science. I really want to be a theoretical physicist some day
Im NOT an Astrophysicist but thanks for the great videos.The best way of learning so amazing facts and physics
Wanna become an astrophysicist? It's one of the best decisions you'll ever make!
chuck is Neil's Ed to Johnny, Paul to Dave, Geoff to Craig. love the match up!!
You guys are hilarious! Thanks for educating us and making us laugh at the same time.
Not enough people watched this.
Great explanation, this video can help young ones be more interested in STEM subjects and their usefulness in modern society.
These guys are hilarious. I wise Neil was my science teacher
And Chuck was a classmate
Chuck is the class clown and Neil is the cool science teacher
Neil is a science teacher for all of us bruh. :o
@@HopDavid Neil isn't teaching a science lecture, rather he is trying spark curiosity and intellectual hunger in those who are not already scientifically savvy. Even though you are right about Fuel Mass going up exponentially by delta v, there was no reason to be elitist about it.
@@HopDavid Neil inspires enough curiosity to make people aware of a specific scientific subject in which they want to learn more. I do not know in what way Neil creates a feeling of superiority, as I watch most of his podcasts and interviews. Also, his support for IFLS is not supporting the misinformation among the blog, rather his objective is to create a curiosity for science as previously mentioned.
That's why i tried to build fuel station in world's orbit when i play kerbal space program. HAHA!
... and now I'm just wondering if there is a video where someone explains the actual rocket equasion. How the calculus in it works...
Saw the title, got intrigued, now gotta learn it))
This is the calculus behind the rocket equation. It has to do with integrating 1/M dM, where M is the instantaneous mass at any given instant, which gives you natural logarithm. You evaluate it from initial mass m0 to final mass m, to find change in velocity as a function of the propellant speed and mass ratio.
hyperphysics.phy-astr.gsu.edu/hbase/rocket2.html#c2
Given either free space, or the approximation of uniform gravity close to a planet's surface, you don't really need Calculus to use the equation. Calculus is used in its derivation, but it is already done for you.
Me too..
@@HopDavid Wouldn't be the first time he gave incorrect information. When he was making an example of how your weight varies as a function of location on Earth, he told Chuck that he'd be 5 pounds lighter at the equator. 5 pounds is unrealistic, unless you are the heavyweight champion of the world record. It is less than a pound for most people.
@@HopDavid You are correct that there are factors working in your favor for more massive rockets. The factors that work in your favor for more massive rockets, are not because of the fundamentals of the rocket equation. It is either due to the practicality of construction where you get more economy of scale out of the empty mass to payload ratio, or due to air drag becoming disproportionately less per unit mass. Fuel is proportional to non-fuel-mass in the fundamentals of the working principals of a rocket. The exponential function, is a function of the deltaV related to the cumulative maneuvers.
Brilliant! Next video, how tall trees carry water to their leaves, 50 metres up against gravity.
This was the first star talk where I haven't learned anything new... I don't know if I should be disappointed or proud
Entertaining and educational ❤️
You two are great together!
You both make a great team. Thank you for what you both do
Y'all literally bring pure joy into my life. Haha so cheese but so true!!
I love how Neil brings science to the people. This guy is a national treasure
@@HopDavid You are very confused.
Another benefit of staging rockets is that you get to change the rocket nozzle. As you rise in the atmosphere, the optimal shape of the nozzle is different. So being able to time your stages to have the nozzle optimized for your set elevation is a huge benefit. The efficiency of the rocket is related to the geometry of the nozzle which in turn reduces the fuel needed thus reducing cost.
Hm, interesting point. Didn't even think of it. Though it makes total sense. Hopefully they will cover this aspect of it in a future video as well.
I loved this episode so much. Maybe I am biased since I work in the field, but the 2 of you killed it with this one! Loved every moment.
If you work in the field, then how did you not notice that his explanation - fuel increases exponentially with payload mass - is wrong? Fuel per payload mass is relatively linear, and actually gets slightly better for larger rockets as there's less fuel tank mass per volume of fuel.
Where the exponential comes in is how quickly you want to change the velocity of that payload. The more quickly you need to change the velocity of that payload, the more fuel is needed. The issue with Apollo and Artemis, and why those rockets are so large, is that the payload will do inconvenient things like die if they run out of air, food, and water, get too much radiation exposure, etc, so they need to get to their destination as quickly as possible, necessitating a huge rocket with exponential levels of fuel to get them there quickly.
If, on the other hand you have something like Capstone, where there's less time pressure to get to the moon. you can do multiple smaller velocity changes spread out over a few months and use a lot less fuel, thus a much smaller rocket (Electron) can do the job.
It's also why rockets use stages. Essentially a large rocket is used to get a smaller rockets up to a certain velocity, then that smaller rocket adds more velocity to its payload, making the change in velocity a function of addition of multiple exponentials as opposed to a single exponential to get the same ultimate payload velocity.
@firefly4f4 cool story bro. You missed a few things. Remember who the demograph this is aimed at. He made a comment, brushing the surface, and ommited a few implied words, which if you're born speaking English you'd pick up instantly, as it's common tongue. If you wanted him to explain to detail, then this wasn't the episode for you. Thanks for the internet flex. Humble yourself a bit. There's more forces at play than you clearly notice, and your expectations are wack. If YOU worked in the industry, you'd know that payload is only a small portion of the industry, which I do not work in payload.
Hi Neil and Chuck love the show!
awesome as always from ethiopia
Here is how we derive the Rocket equation, Neil...
From Newton's law, the thurst of the rocket during take-off is given by,
F= dp/dt
= m (dv/dt) + v (dm/dt)
For rocket v~ exhaust velocity,
Since, there is no change in momentum, before and after take off,
dp=0 this implies, F= 0
m dv + vₑ dm = 0
dv = - vₑ (dm/m)
For 1st stage of flight, on integration,
v₁ = -vₑ ln (m₁) ...1
Similarly for second stage of flight
v₂ = -vₑ ln (m₂) ...2
From 1 and 2
v₂ - v₁ = vₑ ln( m₂/m₁ )
v₂ = v₁ + vₑ ln (m₂/m₁)
If, β is the rate at which the fuels burns,
m₂ = m₁ + βt
Then, v₂ = v₁ + vₑ ln (1 + βt/m₁)
This is the rocket equation, It was first derived by a Russian physicist, Tsiolvysky and in his honor, it is named Tsiolvysky's rocket equation.
I apologize for error, there is m₂ = m₁ - βt
Then, v₂ = v₁ + vₑ ln (1 - βt/m₁) .
once I finished coding my system of growing flowers just like nature does.
I felt like I finally understood the world as it is. Math!
So I went on to make a water simulation....
there's nothing more beautiful than describing nature in mathematical terms.
4:42 and the conversation about fuel after had me dying 😂
I’d love to know if Neil has ever heard of ‘Kerbal Space Program’, a game of physics, rocket building and orbital mechanics. It’s so fun and really gives you such a great understanding of all the physics we don’t get to see visualised and concepts like delta-v TWR and the trajectory’s of ships n how they make orbit.
It would be amazing content to see Chuck trying to figure it all out with Niel coaching him!
If he had, maybe Neil wouldn't have botched this explanation of the equation so badly.
Fuel required increases LINEARLY with payload mass, not exponentially.
Where the exponential comes into play is how quickly the payload needs to reach the needed velocity. Less time requires exponential more fuel.
That's why if you don't really care how long it takes, you can use a smaller rocket to get the same payload to the correct orbit.
Some payloads, like say people, have limits for how long they can be in a small capsule, so they need to get to their destination (ie final velocity) faster, and hence that's why the rocket is so big.
My favorite rocket 🚀 is the Saturn V, love hearing anything and everything about it.
Hi Mr. Tyson, please review the science behind sci-fi series "the expanse". Heard it is one of the most scientifically accurate shows out there.
Chuck Nice should be on national TV, he's a great personality. I'm a big fan and predict he will become a star in the upcoming years. ✨️
Some people say "why spend money on N.A.S.A" ? without N.A.S.A a lot of electronic we take for granted today would not exist. This is why we need to continue space exploration, for new innovations.
Great episode
Alot of love from India
These two make me proud ❤️
Re: drafting on the highway. I can completely confirm this works incredibly well, and is also severely dangerous without additional technology.
Drafting 18 wheelers right off their back bumper - you barely had to touch the gas pedal! Then again, you had no reaction time if they ever had to stop. Luckily they don’t stop short and typically drive pretty smoothly. Unfortunately, they also kick rocks through your windshield really easily, or pieces of their retreaded tire. It’s a scary place to get 100mpg. You’re basically driving behind a moving wall - and there’s no wind. It’s a weird feeling - and not recommended, yet.
I think the future of highway fuel economy is in drafting. Link up the cars so they speak to each other. The car in back can get right on the bumper of the first car. The driver in front slows or hots their brakes, and a signal is sent to the car behind to slow down in unison, not in reaction. You could form “car trains” getting great mpg. Self driving cars could make this happen.
It works well with normal cars drafting. I had a friend tailgate me for 200 miles, at a decent speed (80+ mph) on a road trip. Their thirsty performance car got near 40mpg! It typically got 16 city, 25 highway, and closer to 20mpg at those speeds. Science!
When u are on the space K-mart u are not getting chips and juice, u are getting SPACECHIPS and juice 🥤 🚀
I'd like to see a video explaining the high concentrations of Xe 129 on Mars. Please?!
Here's Vanessa from Brazil! Big fan!
Aw so it wasn't the study of Megatron that showed us how to make Walkmen 😆
Neil being this high for a video makes him so much more relatable!
Not a funny joke, sir.
Agree to disagree
@@kpourhamidi If you want to be insulting to Neil, then just insult him.
@@JasonWW2000 how is that an insult?
I don't think it's noticed how quick witted Chuck Nice is. He's quick with funny comebacks, keep it up bro.
People notice... Dude is hilarious!
Star Talk is sooo great!!
I'm thinking about the perfect gas / volume ratio when filling up my car every time at the gas station and always wonder if I'm crazy. Happy that I'm not the only one and are actually right in my theory! Thanks
Im back Chuck... continue this
If anyone has ever watched Back to the Future Pt 2, you may recall Doc Brown saying [SPOILER] that he was a descendent of the Von Brauns. Science ran in the family. [/spoiler]
ikr!!
Loved this dialogue!!
Chuck is like "that's funny", "now, that's funny", "ha, that's even more funny"... 🤣
Please do a segment on the science behind the truck draft.
I love this 2 guys!
Saludos from Argentina.
Saludos from Canada!
Saludos from earth
I'm in love with this shiiitzzzz!!!!!!💚🧐👍🏾
So Chuck: technically the SpaceX rockets haven’t been to space, just like your planes. If they jettison low enough to avoid burning up, then it’s just like your plane correct?
Sorry Neil, but Wernher Von Braun at first insisted on using a massive single stage rocket to get to the moon. It was another engineer who over time convinced Wernher that a 3-stage rocket was the most efficient way to get to the moon.
They are genuinely having fun sorting out the math together.
I'm back Sir I know certainly this topic is awesome including great ideas to make things to the letter of a safe launch I hope to expand more. To prevent malfunctioning in that the engine agrees with
The ROCKET FUEL it is in the propellents. Today we have breakthroughs in technology blending by viscosity.
Dry propellents do effect liquid fuel and , much more .
Without star talk episode, no sleep
Man... I don't know who is smarter.. Neil with his infinite knowledge of the cosmos or the humble Chuck who manages to understand and elaborate every single thing Neil throws at him, whilst maintaining a great comic ingenuity
No one got infinite knowledge 🥴
@@HopDavid In my project about the spacerace, my teacher wants me to answer this question: "You are required to account for the conservation of momentum and, based on this, derive a differential equation that can model a rocket's motion through a homogeneous gravitational field." However, I have little to no knowledge of how to derive differential equations. I'm thinking I need to use Newtons 2. and 3. law, and the conservation of momentum law, but I'm pretty lost here. Do you understand rocket science and differential equations?
Petition for Neil to narrate all rocket launches
I got a question:
"The apparent weight is equal to the actual weight when the frame is moving with a constant velocity either in upward or downward direction. "
Is this the condition of weightlessness??
If I am in a lift which is moving with constant velocity(net acceleration=0), will I experience weightlessness(my weight=0) then??
If I am in lift whose wire is snapped, will I experience weightlessness?
I got some confusions with weightlessness. Can weightlessness be there when when lift is moving with constant velocity?
In reality, the fuel issue is a lot more complex than they suggest, but this is an excellent video! i.e. if you think about it, you are not sending all the fuel to space, it is being burned off as you rise, so it is a changing amount of mass too.
Love these guys!
wow this is why i listen to neil, next level thinking, keep looking up.
hey neil if you see this can you talk about the future and science of sep rockets.
Food for thought Qs:
What is the rate of weight loss(spent fuel) vs lift height in any given space payload launch?
What is the preferred launch location on earth for a space launch?
Will it be easier to launch from a mountain top(closer to orbit) vs at sea level?
Thanks
ONE OF BEST EPISODE
The autonomous landing debris is great, it might even solve the problem of space debris
7:08 "There's nothing engineers like better then constraints." NO! As an HVAC design engineer, I got so annoyed at architects who CHANGED the constraints AFTER my beautiful design was nearly complete! Chuck had it right!!!
Neil, I would love to see you playing Kerbal Space Program, please, make it happen. 😀👍
5:35 That seems incorrect to me, the amount of fuel should grow linearly with the payload (Simple thought experiment: to double the payload you can just cobble together two identical rockets which will only double the fuel requirement).
It's exponential, if i'm not mistaken. Since every kg of payload requires a certain amount of fuel, every extra kg requires that same amount of fuel + the fuel needed to get that extra bit of fuel into space. In other words, (and to make it more clear let's say 1 kg requires 1 liter of fuel) if you have a 10 kg payload, it requires 10 liters of fuel. If you then add 1 more kg of payload you'll need 1 more liter of fuel plus a little extra because the 1 more liter of fuel also weighs 1kg (which would require a whole extra liter to get up there, and so on and so on ad infinitum). That's exponential growth. Excuse me if it's all gibberish. I have only studied maths/physics in my native language so something obvious may be lost in the translation for me, but i think what i said is essentially correct.
The rocket equation is about how much fuel is needed to gain some speed, and that mass ratio grows exponentially with required speed.
Getting to a higher (further) orbit requires more speed, so getting a given payload to a higher orbit is also exponentially dependent. For example, Earth's LEO speed is about 8 km/s; If we have a one stage rocket with a specific impulse of 250 sec, and need a launch speed of 12 km/s (1.5x) to get to some other orbit/trajectory, that requires a starting weight not 1.5x higher, but 5x higher [exp(8,000*(1.5-1)/250/9.81)].
@@ASJC27 Yes, I suspect that that was the point Neil intended to make, but for whatever reason instead of saying the amount of fuel needed increases exponentially for every extra amount of speed (or distance from earth) he said "for every extra pound of payload".
If we're ever going to get serious about Space we need to get rid of the Fuel Tank and come up with a better solution, like a Rail Launcher or Mag Lift. Fuel Tanks are so 60's...
@@HopDavid Alright, fair enough. Thanks!
Driving in the wind shadow of an 18 wheeler to save fuel is actually not a bad idea... if both vehicles were using an auto-pilot and near-field communications. This is why in experiments with autonomous driving, convoy formations are often used... convoys with very short inter-vehicle gaps, to precisely save fuel.
Gotta admit: I'm with Chuck on the "used" aircraft thing; it's never had its feathers singed.
They say when you're laughing, you're learning and I definitely learned a thing or two about rockets on this video. =D
You were so taken by Phil singing while playing drums. Check out Clevon Little from The Band. Yes, the name of the group is, The Band. Story behind that you'll like.
Fuel consumption when *driving at a constant speed* depends mostly on air resistance, and friction of the engine, transmission and tyres on the road. The car's mass has only a small part in it (it slightly increases friction, but not air resistance or engine friction, for instance). The mass comes into play, however, each time the car accelerates.
....or drives *_uphill._*
One fundamental difference between space travel and travelling inside the Earth's atmosphere (whether by air, on the ground or on water) is that the former only uses energy to _change_ velocity while the latter uses energy to overcome friction even when the velocity is constant.
12:40 Made me laugh so hard. The silly things we nerds do for efficiency. :D
5:35 There is a mistake there. the amount of fuel you need doesn't grow exponentially to the payload. I grows exponentially to the Delta V.
It grows just linear to the payload.
Yup,finally someone notices it
@Neil DeGrasse Tyson! Your awesome! I would love to get you on my Team lol I am working on building a amature space company. Would love for you to teach me the math and all of that !
Damn, Chuck and Tyson are a perfect combo