Neil deGrasse Tyson Explains Gravity Trains
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- Опубликовано: 6 июн 2024
- What would happen if you fell through the center of the earth? On this explainer, Neil deGrasse Tyson and comic co-host Chuck Nice take another look at transportation and explore the concept of gravity trains: trains that are purely propelled by gravity.
Ever been digging a hole, minding your own business, and heard someone say you’re digging a hole in China? Find out why, if you dug through the earth, you would probably not end up in China. What would happen if you jumped into that hole and fell through the earth? Neil walks us through the physics of what would happen. Would you get vaporized? Stuck? Ejected from Earth? What about if the hole wasn’t through the center of the earth? We discuss swiss-cheese Earth and what would happen if there was an underground train through the earth that went directly between New York and California. All that and more, on another StarTalk explainer!
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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!
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0:00 - Introduction
0:26 - Digging Through the Earth
3:05 - Jumping Through the Hole
8:49 - Gravity Trains
11:36 - Closing Notes 
Наука
“Chuck you ever get tired of these explainer videos? Because I could do this forever”
Everyone: please do this forever
We love to science forever ❤️
👍🏻
Watch this then you'll know Neil is lying
ruclips.net/video/WAeBPskvP4Y/видео.html
The wealth of knowledge preset on this channel alone, entirely for free, is hard to describe.
Chuck is becoming the smartest comic of all time through casual conversations.
❤️❤️❤️
Chuck’s journey is great to watch.
But has he tried dmt?
@@alexkang7360 , he seems to already be an enlightened dude. But look what it did to Mike Tyson.
His new name, Osmosis Chuck...
Niel: "You tired of these explainers? I have unlimited."
Chuck: "I'm gonna take you up on that."
Everyone watching the video: "What he said."
Hey Neil - still living in denial of the UFO evidence from the US military - a true scientist explores All the evidence
i was about to say it, but you have seem to beet me. . . in this multiverse
@@tomking2613 lol
@@spookyninja4098 The U means unidentified. So, a UFO doesn't imply aliens or spaceships. You need to get your head out of conspiracy cuckoo land.
@@StaticBlaster I guess you dont read the news buddy = The Pentagon confirms a video of a triangle UFO buzzing their destroyer is real - you were saying ? www.the-sun.com/news/2683726/us-navy-filmed-ufo-sky-video/
Chuck and Neil just compliment each other so well
Just compliment each other? Just? 😂
Bromance is strong with these
As a left hand clasping a right hand, a real chiral pair.
Ditto. Their latest podcast was a party! Really amazing little gang, this two!
It's complement, of course, but we get the picture! ; )
nooOoOooOo! Don‘t stop the explainer videos! Neil and Chuck are pure gold, the 15 or so minute format‘s perfect!
Really wish they would've continued on to ask what if the Gravity Train was applicable to the moon and how long it would've taken.
Watch this then you'll know Neil is lying
ruclips.net/video/WAeBPskvP4Y/видео.html
When I was in 8th grade I asked my teacher if I dug a hole straight down would I create a volcano. She said yes you would, now fill in the name of all 48 states on this map.
@cops and govern ment are gangstalkers By applying science that is very advanced and can't be comprehended easily, The answer to your latter question is doppler effect ! By studying the incoming light of astronomical you can figure out the distance between them
Please never stop doing these. It hurts my soul to think about this star talk series stopping
I'm really glad Neil cleared up the whole thing about gravity decreasing as you get closer to the centre as when I was younger, my teacher told me it would increase.
The gravity doesn't change as you get closer. Rather the amount of planet pulling you in the same direction changes. So as you approach the center, less planet is pulling you towards the center and more is pulling you away from it. As you move away from the center more of the planet is pulling you towards the center and less is pulling you away. The closer to the center you go the higher the pressure will be, and gravity would also increase if the planet was made denser.
Not only that, if you took Einstein’s equations and theory, how will spacetime curvature which is what gravity is, will be effected in a solid object like the earth?!
Einstein: Well actually nothing is pulling on anything. You see, objects can only ever move in a straight line. It is actually space that is curved. Space/time is a framework for thinking about how mass warps space, and how mass moves through that curved space. Think of a rocket ship......
@@Robert_McGarry_Poems exactly! What I’m wondering is how this space-time curve inside a planet? 🤔
He's accually half wrong on that part, and your teacher is half right. This would be the case if the earth had a perfectly uniform density, but it doesn't. The core is much denser than the earth's mantle so the force would increase at the start. It not until you get to about the core's surface it starts decreasing.
Oh, I misread and thought they were explaining gravy trains. I've been looking for one of those for years....
My old welding partner used to say he's getting on the gravy train before our shift. Never really got the reference
@@bens3509 Gravy train = easy street.
Work = security. Something about a bird in the hand and some bush or something. Moral of the story, don't let go of the bird. So, long story short... If you got a job, embrace the benefits it provides.
@@Robert_McGarry_Poems awesome haha. Thank you for the insight!
Watch this then you'll know Neil is lying
ruclips.net/video/WAeBPskvP4Y/видео.html
Lol
I've been waiting for it too.
Oh... now I dig it!
I'm pretty sure this form of travel is in the remake of Total Recall. They don't bother with Mars, they just travel through the earth from one part to another.
And, it was on a track.
Problem is, the deeper you go, the more massive the earthquakes are, and the tunnels created would act as crumple zones.
my thoughts exactly :D total recall train is actually doable
@@witchdoctor6502 no cuz the inside of the earth is 6000 degrees so it will melt literally any material
It was called "The Fall"
@@witchdoctor6502 Well, it is 2021 and we have only dug a 7ish mile hole into the Earth, so only 7,993 miles to go and we'll have the first one....if earth was 8K miles in diameter
please make one playlist just for the explainer videos! That would be a blessing!
Neil and Chuck! You brighten my day and my mind! 💕
Noooo we don't get bored of these explainers😭😭please go on forever neil😤anyone agree?z
That's what made Man of Steel so cool. The Kryptonian World Engine was split between two points on the Earth diametrically opposite of one another. One was on the North East Coast of the continental U.S., Metropolis, and the other part was located in the Indian Ocean.
I love these explainers because they're short and i always learn something i never thought i wanted to know
I go to sleep listening to you guys talk. It’s magical
PLEASE DO THIS KIND OF TALKS FOREVERRRRRR
Thanks for shearing your knowleadge
Oh no, that sounds painful... 😖
@@Robert_McGarry_Poems XD
I love the explainers.my favorite part of star talk
Chuk & Neil the best duo on the internet. I can watch this forever ❤️👍
Your early to a star talk video, congratulations legend! ❤
Yup!
Absolute Legends!
We need longer star talks with chuck. Chuck is legendary
Great idea~ reminded me of the movie "The Core" when digging through the earth was mentioned.
Would love to see more startalk in my lifetime~ cheers!
Pleaaase do them forever!! We’ll watch 😁
I love your Explainer series.
I always thought about this as a kid, that it would be an endless ride to jump down the hole and then have gravity "inverse" on you once past the center. Cool to have NDT explain it!
Yes Professor. Please continue doing such videos. I don't get bored at all..!!!
Unless you do it from pole to pole, you'll smack into the side because you'd retain the angular momentum from the spin of the earth. Maybe grease the sides.
Except the earth (and thus the hole) continues rotating, so it would rotate with your lateral movement? No?
Can't argue against that. Going from equator to equator would possess the greatest angular momentum, thus scraping your skin off on the side until reaching the center. After you pass the center, you can apply ointment to the wounds. lol
@@Zone1BC the center rotation is faster, yes..?
If you went pole to pole would that be Magnetic pole to pole or Axis pole to pole..? Wouldn't the Moons gravitational pull bang you up anyway lol...
@@Zone1BC Absolutely, it does but by how much?
Short answer: it's a normal to tangential axis coriolis effect application.
In actual English: usually giving a rotation as an instantaneous velocity (eg 1000 mph at the equator) is a terrible idea but in this example it's actually helpful to keep things simple. So let's do that!
Ok, you're on the equator doing 1000mph or thereabouts tangentially relative to the centre of the Earth in the direction of rotation at the precise moment you jump into the hole.
The conservation of momentum / Newton's 1st means you retain your momentum. Only physics can have a law that says "do nothing, nothing happens" and see it as profound but there you go... We're ignoring friction here. Keep things simple.
So, how fast are the walls moving? Let's take a point half way to the centre of the earth and so avoid calculus like the plague. That means the circle described at that point is smaller, the radius is smaller. But the rotational period is the same: 23 hrs 56 mins; one sidereal day*
So, half way down the wall is taking the same time to cover less distance than you are from retaining your velocity. That means it's going tangentially slower than you. That means you smack your nose hard into the wall and scrape. :)
The physics here is essentially the same as for why hurricanes rotate in different directions in the N and S hemispheres. As you move north from the equator, the radius reduces and so it's moving less distance but at the same period; 1 sidereal day. All we've done is shift axes.
Hope that was mildly helpful. There's a little more to it than that but this is already long.
*let me know if you'd like me to explain the 4 min difference to a solar day. Or try to work it out for yourself maybe. A little bit of thought and you can figure it out where the 4 mins went...
You guys are both on point! Love these videos!
Wow! Love these explainer videos!!!
One little skipped detail (ignoring the pressure and temperature at the center of the earth) is that once u reach the center u can no longer dig so for this to work u need to dig two holes on the exact opposite spots (antipodal points) and meet at the center.
Interesting conundrum, but once you reach the center wouldn't you still have the second mass of the Earth pulling on you. Since we don't fully understand Gravity and its affect, but you make a great point...
I love these! I want another one where you help us visualize how big space is. It blew my mind when you said that if the sun was the size of a period the next closest star would be 4 MILES AWAY! That was in the twinkling star episode. Mind blowing! I want more of that please! 😃
Extra credit for the pop reference to C.H.U.D! Well done.
More explainer videos please :) I love these
Great topic! I would’ve never known it takes the same amount of time!
I love the explainer videos!
All this digging reminded me of sandworms and the spice melange. Now I kinda wish they'd make an episode dedicated to Dune. 😊
Best summary for Orbital Mechanics: Falling and Missing
Love you both and thank you 🙏Greetings from beautiful Poland❤️
I already learned so much with Neil and, of curse, Chuck. Thank you both, so much!.
These 2 are awesome together. Neil can be a bit obtuse but Chuck has a great way of softening the edges of everything. Their combined facts + humor style is really cool to watch because they're both adding different things and never trying to talk over each other.
Keep them coming Mr. Tyson!
That's why I watch every video! You read the title and it's like "hmm, whatever" but I think it's my favorite video so far :D
Was watching him live and then his explainer is fun
Same
MORE EXPLAINERS MORE OFTEN NEIL!!! ❤
Love how this turned out to be a serious topic 😅😅
I 💕me some StarTalk. I think my favorite was "Warm Blankets." I sent that to a bunch of people I know and they thought I was nuts 🤣
Never getting tired of them
I’m so happy Morlocks got a mention. I love The TimeMachine.
im glad i clicked on this one really blew my mind. I hope one day i can meet NDT
Side note. You would reach terminal velocity quite early assuming there is air in your hole and eventually get stuck at the center after oscillating a few times. Also you would keep hitting the walls due to the rotation of the earth. 👍🏻
If I’m correct (and I could be wrong) you are already rotating with earth so you wouldn’t necessarily hit the “walls” of the hole because you’re rotating with it. But I’m no scientist so....
@@D__Cain true, but as you near center rotation speeds up like a ice skater brings their arms into their body while doing a spin. I think this qualifies as accept for a few details as Neil explained...
@@D__Cain only if you dig at the equator
Terminal velocity is a result of wind resistance.
That's why they said "Not factoring wind resistance."
Dr Tyson mentioned that if we ignored air resistance, then it would take 45 mins to reach the other side. That would be incredible. This made me think however that if we dug such a hole and we had air resistance, if someone jumped into the hole, in case of a distance of 8000 miles, the travel time would take around 66 hours assuming a terminal velocity of 120 mph, right? Or am I mistaken?
I love Startalk. I love Multiverse. Please don’t stop making these videos and please continue to teach and inspire us!
You would *_never_* reach the other side if there was normal (sea level) air density and thus resistance all the way with a 200 km/h (~120 mph) terminal velocity.
You would reach 200 km/h shortly after you jumped into the tunnel on one side and stay close to that speed until you were about halfway to the Earth's centre. There the gravity would start decreasing and you would start slowing down due to the air resistance now being stronger than gravity.
Air resistance would also decrease as you slowed down, but so would gravity until reaching zero at the Earth's centre. If you had any speed left when reaching the centre and thus overshot it slightly, you would be stopped and pulled back by the now reversed gravity, and you would end up floating at the centre for ever.
I wanted to know about this topic, awesome 👍
Great video!!! Thanks!!!
So I'm literally typing a post about 'could we use this to link bases on the opposite sides of The Moon' when Neil goes and answers it. Awesome.
Did you release a paper or something on this? My dad told me about this when I was nine (2010)! It brings back so many memories!
Thanks Neil & Chuck.
That part about satellites taking the same time as a trip through the Earth was a mind-splosion.
Loved it.
Neil you did it again, nice work
Very fascinating.
We will never be sick of these video's.
Love Neil! Love Chuck! LOVE SCIENCE!!
I love physics, it’s the way we make things work while dealing with gravity. Example; distribution of the weight for a load bearing wall of a house we only need to do this because of gravity.
You two are a great team 😗💙
The Morlocks? Nice. :)
Please do this forever. :-)
Sweet. That was a fun thought 💭 experiment.
Great Channel, can be improved significantly by adding more animations/ diagrams with the explanations.
Thank you Neil for taking the place left by the great Carl Sagan to so many of us. Astronomy is always fascinating with you.
They did this in the most recent Total Recall movie... awesome!
My personal take on this which would eliminate the problem of friction for non-antipodal destinations would be to hollow out the earth, and use the spoil to make a black hole, which you keep carefully at the earth's centre (I don't know, using magnets or something). So you just drill a hole through the crust into the big void space, whip around the black hole however, and then hope there's another tunnel (hopefully) at the destination end. That would take care of friction on the tracks, you just have to be careful about the manufacture and handling of the black hole.
Neil you are great. Neil and Chuck you are both just superb!
Mind Blown 💥
Neil and Chuck are the best.
This was so satisfying to have Chuck's expressions perfectly timed with mine during the whole thing.
Of course Chuck loves explainer videos, job security.
Neil: I could do this forever
*Literally everyone*: 📝♾
I love both of their voices!
I am sure Chuck is becoming more smart than he portrays. This dude understands advanced physics just by the 3 mins convo with Neil !!!
Startalk best talk
Love these 2 guys
it's like a trip here in São Paulo - Brazil, if you're near a train station, you take 1 hour other places that have train stations near
I love you Neil and Chuck ❤️
Last video of PBS It's Okay to be Smart explored this topic too, it's worth checking out :D
I was holding my breath the entire video, waiting for you to tell us the speed I would be going, as I crossed the center!!!
I'm a fan of both of yours.
First word of every StarTalk: "Chuck..." :D
8:08 I couldn't control my laughter after Neil's reaction!🤣😂🤣😂🤣😂🤣😂🤣😂🤣😂
Please do this forever Neil
Don’t you EVER stop explaining stuff to me Neil! Lol 🙏🏾but seriously so great full for your knowledge.
The movie I watched yesterday night, the 2012 reboot of Total Recall. It had this thing in the movie called, "The Fall" which was using real science. It was a gravity train that linked the U.K. aka the UFB in the movie with The Colony aka Australia. That could work that's if you could drill a hole though the Earth to link both places, which is a huge if but still cool IMO. It's funny how StarTalk released a video about this the day after I watched a movie that showed a gravity train as a main plot devise...
I watch you guys everyday
I exactly did this calculation for my Engineering Entrance exam and got the exact result! It's kind of oscillation concept
So, what did you forget to theory calculus?
Approximately, 0.987 extra weight time's, every 1234 miles in towards the core creator?
I was about to say what about air resistance, and then he mocked me with monsters xD
could you make the gravity train curved such as if it went around the core slightly? ( Which at that distance I would think slightly would put you somewhere way different)
I know this was posted a year ago but,
One thing I found interesting in this is as you get closer to the center, the less you weigh due to gravity, and the closer you get to the top of a mountain on the equator the less you weigh due to centrifugal force.
Let's just say.. You finally beat the equation, by being a supermen & say like, CHINA was the first men on earth, to win that G-train noble trophy!
So, than finally, you think you got, all the equation finally counted through & taught that, I'm be like the first human to test that g-train & no equations is gonna stop you ( since you did all of it & was rest assured )
Once, you're the first men, to finally " 0ne giant's leap for Humankind " sort of Go Go Spirit & suddenly you're realized, that when there we're no equation holding you back, you are stucked in the middle of center earth
Not just, one nights but more than a months.. and crap, there is still an equation that's not right & R.i.P theory my men!
3:21 I'm a physics major and the proofs of the gravitational shell theorems are beatiful. The geometric way it was explained was intuitive. Imagine a mass m, that is located inside a spherical shell that has a constant density. This shell exerts gravitational forces on the mass m. Without getting into the calculus, if the mass is closer to one side of the shell, feeling a gravitational force from that side of the shell, but the math works out that the opposite side of the shell produces the same force in the opposite directions canceling out the forces. This mean that m feels no net gravitational force.
This remarkable phenomena depends crucially on the fact gravity follows an inverse square law. If gravity didn't have this inverse square law property, m would feel a non-zero net force.
I clicked on this video to find out how to get on the gravy train. I didn't find that out but I did learn something.
Well yes, I have actually thought about this before because I'm in graduate school for aerospace engineering 😅 this is one of our professors' favorite questions to ask during comprehensive exams- derive the equation of motion for this scenario, and then of course solve the differential equation
Mathematics is the most terse way to express an idea. Would you get marks if you explained what's going on entirely in English?
Just to add in, what if you were carrying a light on your way as well can you observe someone failing completely through the hole? They'd have to jump in true to the center of the hole but that isnt what stars do that we have going into black holes. So if you had a light and no light was shining from the other side because no one is there and you jumped in from the side of the hole, could I see you sort of orbit into the center or will you fall so fast and get out on the side before I can see the light escape from behind you? Hopefully I asked the right questions! Thanks neil