Why Doesn't the Moon Fall Down?

[Omid45]

I wonder what would happen if Earth were to escape Sun's gravity or fall to it. Imagine Earth accelerating!!! The whole earth would become like a fighter jet. Everyone on earth would feel a lot of G's lol. I wonder how that would feel?

[SirSpoon84]

sorry lady, your wrong

[ink4852]

When I heard that I was like "What?"

[Deed1992]

apparently the moon is moving away from the earth at a rate of about 3.8 centimeters per year

[Remousamavi]

Accurate to the first part. But if the moon were going slower or faster, it would simply take an elliptical orbit rather than circular. You'd really have to slow it down a hell of a lot before its path came near enough to the earth for the moon to collide with it.

[mszs]

Even the fastest moving tennis ball will come back to earth? No! Of course, no one could throw that fast or it may vaporize while flying through the air. How much is the escape velocity?

11km/sec?

[FatCrayola]

its 11km/h going up so that gravity doesnt pull it back down i think

[jamieball]

The moon is cool but kinda creepy too!

[swimfly2012]

....yah.

[pandykc]

Actually how does anything, such as stars and moon gets its orbit speed?

Maybe one day human technology could use the same idea to travel in space?

[tennisrules621]

we already do. we use planets like mars and jupiter to get space craft to gain speed when traveling to the outer solar system

[Mifrel]

The moon is an space ship... i dont Know but i prefer to believe in that.

[matstripe18]

yea it go flying back and hit u from the back of ure head

[Ununennium119]

Uh...

Today in gym class we were using Ping Pong balls and one of the balls that I tossed bonked my coach on the head (lightly, though, and on the top of his head, not the back). Weird, huh?

[BloodHuman3]

7 letters.

G-R-A-V-I-T-Y

[whatnameshouldiget]

THE MOON IS ACTUALLY A FART.

:3

[jcurcicool]

this is very interesting

! im gonna find more information to wite this down in my own personal notebook! :)

[xxxglamourbabexx]

Wow! That actually makes sense. Thank you for this video, she is a smart lady!

[308813062]

it does seem that an orbit is a stable state of motion. however, according to the Theory of Relativity, there are gravitational waves emmited by orbiting objects that take away the energy. as a result, the objects get closer and closer together and eventually crash. luckily, this won't happen to the Earth and Moon anytime soon, as this effect is noticeable only at very fast orbits.

[CherriesJubely]

the moon is falling at a rate of 1/20" per second(or 3.32km per year) towards earth, it will hit eventually but not for a while

[queendagmar]

every sun eclips the sun gets less covered by the moon. this shows the moon is moving away from the earth. i cant explain but it is true.

[Surfurplex]

The moon is moving a few meters away each year, in a few billion years it'll be gone, which will have a huge impact on life on earth.. If the sun hasn't exploded or something

[ActiveStorage]

so what causes the moon to go at the same speed without slowing down?

does it have some buster engines or something? lol

[sjsawyer]

It's in a circular orbit. If it were in an elliptical orbit, it would move faster as it is near the Earth and slower as it moves away from the Earth.

Why doesn't it slow down? The only force acting on it (well, the dominating force acting on it) is Earth's gravitational field.

[ActiveStorage]

i mean the space vacuum in not an absolute vacuum therefore regardless to enormous mass of the moon it have to eventually slow down due to friction. Same thing happens to human-made satellites or space probes. Tho it doesnt happen to moon or to our planet, or to any other planets of the solar system. Cause their orbits are so stable. My question is what makes this orbits so stable?

[sjsawyer]

In theory yes, but in reality it doesn't make a difference. It's like the classic example of walking from a point in your room to the wall. In theory, if your first step towards the wall covers half the distance, and then your next step covers half that distance, you'll never get there. But in reality, you're going to get there. I guess that doesn't really relate but you get my point.

I think the main reason satelites have to be adjusted though is because the orbit isn't perfectly circular.

[ActiveStorage]

i think some very insignificant forces are missing from the equation. Electromagnetic interactions anyone? google plasma universe if u feel like it

thanks

[SpitzerJim]

You're right that orbital mechanics are a lot more complicated than this simple explanation. There is still some atmosphere in low orbit (but still little enough that we'd call it a vacuum), but out as far as the Moon, the Moon itself is more of a source of atmosphere than the Earth is. Also, Earth's gravity isn't actually perfectly uniform, causing low-mass satellites in low orbits to "walk." There's a lot involved in keeping an orbit stable!

[ballesteros123456]

Thanks!!!!!!!!!!!!!!!

[ohue]

U only need to understand that GOD is great!!

[sjsawyer]

blehhhhhhhhh

[ImmenseRaven]

What hotty

[ganymedeIV4]

Geosynchronous planatary orbit homies.

Knock the moon though. and were screwed. amazing how extremely fragile the balance of life is. hell 3,000 miles farther away from the sun and we are all dead!

[PatrioticEagle50]

Life is not as fragile as people think. The area that live can exsist in the solar system that is not a moon is between mars and venus. I say not a moon because because the moon galalaeo (or however it is pernounced" might have life.

[ganymedeIV4]

well just think how cold it gets in the winter when your part of the earth tilts away from the sun. Now think what would happen if the whole planet moved a little farther away.

[PatrioticEagle50]

The max. distance we could be is mars' distance. 3,000 miles makes little to no difference. A little colder but we would adapt. We could live a million miles away. But it would be cold, but life is highly adaptable to most weather changes. It takes alot to make ALL life extinct.

[USSRRussianPower]

excellent explantion thankyou

[flangelet]

... because it doesn't want to!

And you cannot force a moon to do anything it doesn't want to do!

Moons are like that!

[eseskay99]

I understand that the moon is actually moving out of earth orbit at a rate of 3.2 cm per year. In a few billion years, the moon will be gone and this will have disasterous effects on earth climate.

[farerse]

i was gonna ask that. is earth orbit around the sun also moving out? or closer to the sun ??

[indiasrainbow]

good question. i wonder if the sun will die before the earth escapes or falls toward our sun? either way lets hope humankind finds a way out of this pollution age so we can find solutions to these and many more natural threats in the future. :) !

[farerse]

yeah i agrree but shouldnt someone figured this out by now?

[thex0009]

if only other astronomers could explain it so easy like this instead of that complicated crap

[shinyam75]

I completely agree. Once explained properly, it's not hard to understand, and makes it interesting.

[fuckingprick]

She so pretty

[sicarius100]

I for one like it, It's simple enough so the younger kids understand.

5*

[EskolainenKarma]

Wrong. The moon is moving away from Earth as both earth and the moon grows. Their electromagnetic fields increases but the relationship remains in equilibrium. This happens between earth and the sun as well as for all celestial bodies. Gravity is an effect of electromagnetism that scientists have yet to figure out.

[sabbellita]

The whole universe with its satellites and planets is something wonderful that we can't imagine

[banghelmi]

I give you one star only for this false knowledge...

[banghelmi]

I think this is stupid and false knowledge... because the orbit is ellipse or oval like egg, is this theory is true, of course the earth will fall to the sun because there is a far distance an short distance between sun and earth in one year cycle (far mean lower gravity, short mean higher gravity)...

and so the moon to the earth..

If this theory is true, the orbit must be perfect circle!!!!

You Fool!!!

[sicarius100]

This is alot simplified, due to the fact that it's targetted to the younger generation.

The fact is that there are more forces dealing with the moon than just Earth, i.e. the sun and even the other stellar bodies, thus creating a slightly oval orbit but it's not really that oval.

If you'd want to go into precise science of the relationship between the earth, moon and the sun then it won't fit into a youtube video and most people wouldn't bother watching it.

[Midnight587]

it's really interesting.i found out sumthin new too.the music is cute. LOL LOL

[Time4CymeTyme]

5 stars..love it!!!!

lol ... if the moon would fall on us we eould be dead!!

[dingorex]

looped

[SpitzerJim]

You try getting good audio on the side of a telescope dome on top of a mountain! ;p

[ptaba123]

this is one of the greatest videos i came across, omg its so trippy

[Agen0]

And the orbit is sustaned, because there is no air resistance to slow the Moon down. Just wanted to add that.

[fireitupbaby]

but will it not fall on us? Gravitational waves add "friction" right? or do i have this backwards?

[5thElement15]

This was really great!

[DuffyTy]

This is completely true. Although at one point in our history, we experienced shorter days because the moon was closer to the earth. Also, in the winter time, the days get shorter because of the angle we are on. In the summer we have longer days. In the winter it turns dark at 4 o'clock. In the summer it turns dark at around 9:30!!

[PenguinCharmi]

im not sure if this is true but a really long time ago earth had shorter days(less than 24hrs) this is beacause the moon was closer to the earth(this meant the moon orbited earth way faster) if the moon kept going farther away from the earth is it possible that earth can have longer days and that the mon can break out of earth's pulling gravity?

[SpitzerJim]

Yes, current models lead us to believe that the Moon has slowed Earth's rotation, and will continue to do so. But the Sun will expand to a red giant and envelop the Earth and Moon long before the Moon breaks completely free of Earth's gravity.

[SpitzerJim]

Actually, the Moon is moving a tiny bit faster than a stable orbital velocity, so it's moving away from us very slowly. The change is so slight that it can't be perceived, even over the entirety of human history.

[Djeezes]

Oh thought it was something like that :p

Will it eventually have consequences for the earth? Probably withing billions of years but still =)

Thanks btw

[SpitzerJim]

I don't know if anyone's ever done a comprehensive study of the ramifications of the moon being farther out, but I would imagine the most noticeable would be a reduction in the effect of tides and the fact that solar eclipses would stop occurring.

[KevlarHead666]

the moon is falling down to earth just as much as the earth is falling down to yhe moon

[sureno5138]

while we are walking gravity is pulling us back

[tharwpoop]

i thought it was an eliptical motion not a perfect circular one

[SpitzerJim]

It is. Perfectly circular orbits don't exist in the real world, but they're easier to understand.

[discountzone]

ok jim i want you to go to youtube search and type( General relativity & Gravity )and when you done watching it let me know ..i really wanna know which one is right i love those stuff . there they say it is not the same force so ? and by the way i think newton was the smartest physicist ever and NOT einstein ..anyways please watch that video and let me know some ..thanks

[SpitzerJim]

Yes. The moon doesn't fly away because of gravity. It doesn't fall down because of its speed.

[discountzone]

ok so that means that the force that pulls us down is the same force the keeps the moon in orbit ? or the reason that pulls the moon and keep it circuling around the earth ?

[discountzone]

the moon follows the worps and curves in the curviture of spacetime fabric wich i've recently been studying about it . infact if you go about 200 miles upward u'll loos gravity and the moon is 238 thousand miles from earth so how come earth gravity can affect it ?

[SpitzerJim]

You don't actually lose gravity, you feel it less (and you end up in "microgravity") but it's still there. The sense of weightlessness comes from the phenomenon of always falling when you're in orbit, the same way you feel weightless when your car drops down off a bounce in the road.

[discountzone]

its kind of weird because as far as i know the gravity that pull us down it not the same gravity inwich the reason of keeping moon in orbit as far as my knowledge its the result of the curviture in space cause by energy and mass gravity is our experience of that curviture produced by the mass of the earth so in other word ...

[whiteboyjimmy20]

Wow, so..if the book is right (book is called: Cosmos A Field Guide by Giles Sparrow) Then that means I knew something that an astronomer didn't! And I taught YOU something! :) P.S You Rule Spitzer Jim

[whiteboyjimmy20]

I read from a astronomy book that Triton (Which is Neptune's moon) is falling closer and closer to Neptune and should hit it in like 10 million years. Is that true?

[SpitzerJim]

Probably. I'm not really up on the details of Neptune. But in the real world, it's almost impossible to maintain exactly the right speed to have a stable orbit forever. We think the Moon is actually moving farther away very, very slowly.

[mrcraig41]

The Moon is moving further away from us by about 3.8 cm per year. Thanks to Apollo missions 11, 14 and 15 laser reflectors were carefully placed on the lunar regolith. Laser light from Earth stations is routinely aimed at these reflectors. The Earth-Moon distance is known with great precision as a result.

[SpitzerJim]

Excellent information.  Thanks!

[kbilyak04]

Ok thank you.

[kbilyak04]

At the very end you said some satellites are launched beyond Earth's gravity and orbit the Sun. Are you talking about the Geosynchronous satellites?

[SpitzerJim]

No. Geosynchronous orbits are still orbiting around the Earth. The way they work is they're exactly the right distance out that the speed of their orbit keeps them over the same spot on Earth at all times. The term for an orbit around the Sun instead of the Earth is "heliocentric."

[mad05963]

Do we need it? yes, its an important part of the ecological system. Does the earth need it? No not really, neither does life in general, Life on earth would probably be a bit different.

[nawitus]

Moon is "escaping Earth", it is just doing it very slowly.

[Envx]

I'd do her.

[roffelmeh]

zeitgeistmovie*com

[perfectionbox]

Okay, but why does the lit side of a 3/4 moon not face the sun directly? Wait until both sun and moon are in the sky near sunrise and you'll see what I mean -- it's as if the sun should be higher.

[Benjo316]

I believe(And this is just a theory) it may be that the earth reflects light onto the moon but the other side of the moon doesn't get any light(From our sun) and therefore remains dark. ^.^

[NerdFury]

there is actually no dark side of the moon. the moon rotates in such a way that it always has the same side facing us, but the moons position relative to the sun changes as the earth and moon rotate around the sun. every side of the moon recieves light at some point.

[Dbzmegaguyyahoocom]

Yeah, I didn't mean that it never got any light, I was just trying to explain why it looks like there is more light than should be(Since the Sun isn't between the Earth and Moon it wouldn't get any light(That we could see) unless it is being reflected off the Earth.

[shoeskid]

Comets' tails point away from the sun :P And there is no down in space, anyway.

[lordmetroid]

Everything is relative, sure there is a down depending on what you define down as being. In this case down is defined as the vector of the gravitational pull of earth.

[superharmonic]

nice! but how do you explain crazy orbits that comets have???

[waluum]

So if a large space rock were to hit the moon head on, against its orbit, and slow it down, theoretically it could then fall down?

[SpitzerJim]

Yes, if you slowed the Moon down, it would start to fall down toward the Earth and eventually hit.

[cheztir]

You really don't understand. Do tides and Spin Stabilization mean anything to you?

[chewielogan]

you do not understand sarcasm.

[jouglet]

Hell yes we need the moon. Do you understand anything about tides?

[mad05963]

hmm, I believe the correct answer is that eventually the moon will slow down enough to fall to earth.

[SpitzerJim]

The latest figures I've seen show that it's slowly escaping, but that gets into some very advanced orbital mechanics...

[JcDizon]

I like these 'Ask an astronomer' videos. Their explanation are clear

[ichsuka]

nice

[sillysot]

Great job explaining orbits!