The Moon's Orbit is WEIRD

[@edibleapeman2]

Didn’t expect to have my entire conception of the Moon decompiled today, but here we are. Thank you for making me feel young again.

[@pierrecurie]

The sun is HUGE

[@rockets4kids]

If you don't remember Spirograph you can't be that old! kzbin.info/www/bejne/gpPZnn6wm8SqqJY

[@aldunlop4622]

As well as feeling a little silly to be honest.

[@LightBusterX]

So Ducktales was right. Welcome to the planet Moon.

[@paladro]

now that they explain it, it makes complete sense... how about that.

[@1.4142]

The three body annoyance

[@travisderthick9361]

Technically not a 3 body problem 😅 Because the sun is so massive. Everything is a 3 body problem or nothing is lol

[@Irondragon1945]

the triple corporeal inconvenience

[@1.4142]

@@Irondragon1945 the tri-object dilemma

[@John_Smith.]

@@travisderthick9361 It absolutely is a three body problem. The fact the sun is much bigger really doesn't matter.

[@nihad6727]

Jupiter would like to have a word

[@stevewithaq]

0:49 The ancients amongst us were just reminded of the Spirograph...

[@woob31]

Oh yeah !

[@constance.mcentee]

Yup!

[@1_____________________]

amon.. amo... amongu... a... amo..

[@danpatterson8009]

Oh, thanks for that. First thing I thought of.

[@five-toedslothbear4051]

My thought exactly. I'm older than the original Kenner Spirograph, the toy introduced in 1965 (though invented earlier, and based on earlier toys).

[@urotaion9879]

2:12 absolutely mental movement right there

[@BierBart12]

What it looks like when you add a number in Universe Sandbox(if it doesn't instantly cause a collision)

[@urotaion9879]

@@BierBart12 honestly yeah

[@soyanshumohapatra]

😂😂

[@sembalo1776]

Deja vu

[@andrewhooper7603]

GEDDAN

[@nathancoupe-gunter9247]

1:32 is a poster just begging to be sold. I was fully captivated by it for at least 10 minutes. Bravo for all you've achieved on this channel Henry!

[@samthestache8]

Minutephysics, I have one small critique. This was a very interesting video, and the little notes yoy kept putting up on screen made it more so, but if you are going to do that, can you leave the note up slightly longer? With each note only being up for about a second, on mobile I was struggling to pause the video fast enough to actually read the note. Each time one appeared I had to back up the video and try again 2 or 3 times. Its a small thing, but I hope you consider it.

[@JDPurvis]

first time viewer, and I came here to say the same thing. Plus the position of the notes means that they're hidden by the video progress bar when paused.

[@k.h.8440]

@@JDPurvisand also hidden by the captions

[@trevinbeattie4888]

Could you play back the video at a slower speed?

[@pufthemajicdragon]

@@trevinbeattie4888 Changing playback speed or rewinding frame-by-frame is a lot harder on mobile. I'm a PC and still have to pause, hit back, then frame-step to find and read the notes. I love the notes, but have *always* wanted them to be just slightly easier to read.

[@Archimedes.5000]

The notes stayed on the screen fairly long compared to the standard

[@landonkryger]

IIRC, Jupiter's moon Io is one of the few moons that does trace out loops.

[@cube2fox]

IIRC = In case I remember correctly

[@pedrolmlkzk]

​@@cube2foxif I remember correctly

[@General12th]

If I remember correctly in case I remember incorrectly in which case my memory was incorrect

[@patrickskelly8517]

Jupiter's moons Io and Europa (and minor moons closer to Jupiter - Metis, Amalthea, Adrastea, and Thebe) form loops. So do Saturn's moons Mimas, Enceladus, Tethys and Dione. So do Uranus's inner moons Cordelia, Ophelia, Bianca, Cressida, Desdemona, Juliet, Portia, Rosalind, Cupid, Perdita, Belinda, Puck, and Mab; and Neptune's inner moons Naiad, Thalassa, Despina, Galatea, Larissa, Hippocamp, and Proteus, although most of them are tiny moons under 100km. Moral of the story: there are a ton of moons in this solar system.

[@SSGranor]

@@patrickskelly8517 _A_ ton? There are about 700 quintillion tons of moons in this solar system.

[@lvcifer-cloverfield]

The visuals for this one are really impressive. Incredible work, this must've taken ages

[@vpsjdon]

Haha I think this is the first video where I ALREADY knew the answer. My science teacher in school told us that the Moon's orbit from the perspective of the Sun would look like an Imarti (it's a sweet dish that looks spirally, google it ). But I wasn't sure so I tried to create an entire animation in After Effects and tried to be as close to 'scale' and correct orbital periods as possible. Eventually I found that the Moon barely curves at all and for all intents and purposes, the orbit is quite circular

[@nakulsprakash1640]

Off topic but imarti is sooo goooood

[@CrimsomGloryXD]

​@nakulsprakash1640 the Imarti is clearly there, so it is not off topic smh /j

[@typhonnix]

do you have the animation?

[@michaeldamolsen]

It warms my heart to know that there are still people out there that "do their own research" the right way. Well done :)

[@alanplateadocastro831]

Did you eventually become a physicist?

[@davidci]

2:12 Was the worst possible time for me to take a sip of chocolate milk

[@Alan-m4y]

The Moon: *Drddrrrd4d4drdtdr*

[@MikalCaober]

2:03 lol did the Moon/Earth run something over?

[@harjutapa]

No they ran into each other

[@Benoit-Pierre]

I also felt that one ...

[@Benoit-Pierre]

​@@harjutapathé earth hits something, and one fragment hits the moon.

[@BenwareSomedaySoon]

Hit and run

[@MsZeeZed]

Nope, that 130 year old pin in the spirograph set finally snapped 😹

[@ZetaFuzzMachine]

1:31 thanks for spending the extra time completing the graph! It was very much satisfying

[@duncanbeauch9598]

Seeing the tools you use to create your animations is so cool, I'd love to learn more! Maybe a behind the scenes...?

[@socalminstrel]

"Should we then say that each part of the Earth independently orbits the sun?" Yes. Yes, we should. I will absolutely be saying that from now on.

[@genio2509]

The Phosphorus atom that is in the right 17th phosphodiester bond of the MC1R gene on the 3rd neuron of my hypothalamus orbits the Sun independently of me ☺️

[@CaseyHancocki3luefire]

agree, 100%

[@CaseyHancocki3luefire]

@@genio2509 what about the electrons of that phosphorus atom though?

[@genio2509]

@@CaseyHancocki3luefire Oh yeah. The Gluon between the two up quarks of the proton #7 of that exact phosphorus atom is orbiting the Sun independently of me

[@CaseyHancocki3luefire]

@@genio2509

[@ahmedyusuf1000]

Could the moon be orbiting the supermassive black hole at the center of the milky way if we're gonna think like this?

[@TheExalaber]

No, because Sagittarius A* does not dominate the galaxy in the way that the Sun dominates the solar system. The Sun alone has enough gravity to capture allmost all of the bodies in the solar system, but Sagittarius A* only has enough gravity to capture a fairly small section of the galaxy, and the rest is held in by the gravity of all the stars and dust in the galaxy. That black hole is the largest contributor, and it is at the shared center, but it is still only a small part of the whole.

[@Dam1an9X9]

@@TheExalaber interesting

[@chrism3784]

@@TheExalaber great answer

[@HensonL]

Nice

[@archaonzero7401]

My limited understanding is that we cannot account for 95% of the gravity holding galaxies together. We call that 95% "dark matter", but it is really something we cannot understand yet. It could be a new type of particle, a crucial error in our models, some kind of spacetime curvature or even influence from another universe.

[@davezarzycki]

Thanks!

[@samwallaceart288]

This is why time travel movies should also factor in orbital drift. Even if you can tether the time machine to heliocentrism, where you're standing on Earth isn't the same as where that spot was 5 minutes ago.

[@RCAvhstape]

Also, the Sun is moving through the galaxy at tremendous speed. And the galaxy is moving through space at some huge speed, and so on. There is no fixed grid to any of this, so your hypothetical time machine would have a hard time figuring out where to put you.

[@GeekProdigyGuy]

But there's in fact no absolute reference frame at all; it makes just as much sense to travel back in time in the reference frame of, well, yourself, as it does to choose the reference frame of the sun or Earth.

[@jaykiknavenaga2121]

appear in the middle of the space? sounds fun

[@bf99ls]

@@jaykiknavenaga2121 Or in the middle of a star! Or black hole.

[@ItsJJOLO]

Following the moon while it orbits, having it change too while it’s still moving, was pretty impressive compositing

[@LucianLazuli]

We're so back!

[@jasonremy1627]

Sam? Ben? Adam? Is that you?

[@Grifonger]

We are just orbiting

[@danielburleson563]

What?

[@sublimeade]

No

[@BudgetCat164]

WERE SO BACK

[@hydrocarbon82]

Like any long-term relationship: it's complicated Like any Brilliant-sponsored vid: it's discounted

[@apollomartin6572]

The Moon did used to be closer to the Earth! So was there *ever* a time that the Moon made cusps or spirals around the Sun?

[@SgtSupaman]

Given the bit later in the video about how even a point on Earth's surface isn't going around fast enough to loop, I would venture to guess that the Moon has never been close enough to make loops. The Earth is just traveling too quickly around the Sun for that to happen. If Earth's speed moving through space around the Sun were slower, then it could make loops (though we might, at that point, not be traveling fast enough to sustain orbit).

[@apollomartin6572]

That was my first intuition, but then the orbital speed when you get close enough is much faster than Earth's diurnal period (the ISS orbits in 90 minutes or so--does the ISS make spirals?)

[@panner11]

​@@apollomartin6572For it to make a spiral, it would have to be traveling faster than the earth's motion when it's going opposite to it. Looking at the speeds, the iss travels 30,000km/h relative to the earth, but the earth's orbital velocity is over 100,000km/h. So it seems even the iss is not fast enough to create spirals.

[@Dragonmastur24]

@@panner11 That leads me to ask the question if there even is a non-gaseous moon that achieves spirals

[@weylinpiegorsch9253]

​@@Dragonmastur24 There's another thread that talks about a large number of moons of the outer planets making spirograph-like loops

[@DartzinhoV]

After 3 years of actual physics classes in uni, it’s really interesting to be able to fully grasp what you’re saying beyond the surface level What’s also interesting is that nowadays, the speed at which you explain things really makes it seem like “Minute Physics” when comparing to a normal class

[@dyssisme]

Hell yeah Minute physics back

[@timothymclean]

It has been a single (1) month.

[@davidroddini1512]

Or in this case 5 minute and 29 seconds physics 😉

[@rosiefay7283]

0:20 That is still consistent with the fact that the moon orbits the earth.

[@Froany]

Amazing visualization transitions between possible configurations!! So cool!!

[@Reoh0z]

> "...possibly futile endeavour." I love that you called yourself out, but this was interesting all the same.

[@PeteVanFleet]

I was more interested in his procunciation of futile, TBH. :)

[@Delibro]

@@PeteVanFleet I as a German only ever heard this word in Star Trek :)

[@joseywales6168]

4:45 but...but its a correct statement- even if its unnecessarily precise

[@PalaeoJoe]

No.

[@user4241]

It is not correct, since objects on Earth's surface are attached to it.

[@hackman-hackman]

Wait till they find out that the Sun itself is moving around in the Milky Way at 450000 miles per hour

[@micha3624]

which maybe orbits around something even bigger maybe :)

[@patrickskelly8517]

The situation is similar! The moon never does any loops relative to the center of the galaxy. It is moving 230km/s around the center of the galaxy, 29 km/s around the sun, and 1 km/s around the earth. So during a full moon in January, it is moving 260 km/s relative to Sagittarius A*, and during a full moon in July it only slows down to 200 km/s, never going backwards. However, it does have outwards curvature (the acceleration towards the sun is 10^-6 km/s^2 compared to 10^-13 km/s^2 toward the center of the galaxy), so it falls into the "wobbles" section of the graph, shaped kinda like a flower with 2 billion petals rather than a polygon with 2 billion sides.

[@hackman-hackman]

@@patrickskelly8517 woah, thanks! I was just doing the math too

[@Reptilia12]

This is exactly why I don't believe time machines would ever be possible, even if time travel was possible.

[@hackman-hackman]

@@Reptilia12 I had a sci fi comic in which people would use time travel to get from China to the USA since, upon time traveling, the location coordinates of the user would stay in the same in the reference frame of the Milky Way

[@rajrigby8385]

I am eagerly awaiting a video delineating the Roche radius, Cebotarev radius, Hill sphere and Lagrange Points 😀🙏🏾

[@bedisraeli]

"Delineating", I saw what you did there! Yeah there are many concentric spheres in orbital mechanics

[@IS-zk9be]

The best explanation I've seen showing the Earth-Moon orbit. Particularly the illustration of the common centroid rotation starting at 3:38.

[@existenceisillusion6528]

I had a professor tell me the physics program should be 5 years, not 4, due to all the stuff we need to cover. Among the topics they chose to cut, this was one of them. It makes sense, since this appears to be more about geometry than core physics. It's one of those things that seems obvious in hindsight.

[@abhay06976]

excellent video with all the relevant equations and still not too long duration! Beautiful and Informative both !!

[@Astronomynatureandmusic]

You crammed an insane amount of knowledge, terminology, wit, graphics, math, physics and animations into one gem. Terrible for me and my type of people, who either will need rewatching this video 50 times at 0.25x or need an hour long documentary to even comprehend. Still loved the video

[@Delibro]

Watch other videos in between, then rewatch it. One needs different viewpoints.

[@LeonardEisen]

@2:00 I love that to demonstrate a change in the moons orbit you seem to show it colliding with some kind of object, with a little explosion. Very neat detail.

[@patrickskelly8517]

Doesn't the centrifugal force exactly cancel out the force of gravity for any body in orbit? Because in the rotating reference frame they aren't accelerating towards or away from the sun (assuming a circular orbit). Wouldn't the Earth's gravity be greater than sun minus centrifugal (zero) no matter where the moon is?

[@minecrafting_il]

but the orbit isnt EXACTLY circular

[@AncientWildTV]

ive heard that Moon's gravitational attraction to Earth is indeed greater than any effective centrifugal force acting on it due to Earth's rotation around the Sun. But still not very sure

[@RobKaiser_SQuest]

"Wheel within wheels in a spiral array; a pattern so grand and complex Time after time, we lose sight of the way our causes can't see their effects"

[@ioresult]

4:12 Tell that to the Trisolarans!

[@MyBiPolarBearMax]

You probably shouldn’t. Best to remain quiet. 🤫

[@nikshaychugh4893]

At @1:31 we see that there is a sort of phase transition in loops, wobbles and convex orbits. Can this be studied using known techniques in stat mech? We could introduce orbital distance of the center of force as something that has a Boltzmann distribution to be peaked around the actual trajectory and a temperature parameter that fluctuations?

[@ThewOrldIssqUare]

⚠️ 1:23 squircle alert ⚠️

[@jhatzi99]

Easily one of the best minutephysics video. Everything very clearly explained and demonstrated.

[@lexfrancis5916]

4:43 unless.....

[@SimNico]

We should be thinking in terms of energy (either specific orbital energy or C3). The Moon has negative energy relative to both the Earth and the Sun, therefore it is gravitationally bound to and orbiting both at the same time. From there, deciding which one it "orbits more" than the other is just a matter of interpretation.

[@happyvirus6590]

1:47 They looked like two travelers where the younger one hops around the other as they go

[@KuruGDI]

3:18 Sorry, but having such long notes in the video only for a very short amount is nothing but a bad idea. If you don't understand what I'm talking about try to pause on the note with a mobile player. Then you will understand. (So either make the note stay longer, or make it short enough to be read while on display, or talk about it, or just leave it out).

[@jordanfry2899]

Brilliant animation!

[@Stephen-gi1rx]

Interesting. That explanation has implications for the definition of a planet by the IAU since under that definition the Earth would arguably be a dwarf planet like Pluto rather than an actual planet

[@akeem2983]

I think that our definition of the word "planet" is almost certainly flawed, but in order to properly clean it up we probably need to do a lot of studies of exoplanets, just to get more points of data and more edge-cases

[@bland9876]

Now we need the follow-up video that talks about the other planets in the solar system and how their moons orbit.

[@BestHakase]

A lot of other moons make spirals

[@jeremy5602]

This explains why the moon is ever so slowly drifting away from Earth

[@YeenMage]

Now we are opening another can of worms: Should the Earth's Moon be considered a dwarf planet just like Pluto? Or maybe Earth should also be a dwarf planet since it technically hasn't cleared its orbit of another massive object as it is technically co-orbiting with the Moon?

[@woodfur00]

How do you define "technically co-orbiting" in a way that doesn't include all moons by definition?

[@billcook4768]

Nah, we should consider Pluto a full planet.

[@trilloff]

No. 3:35 This defines whether we are 2 dwarf planets or a Planet and a Moon. If the center of mass was outside, we would be. Keep in mind, the Earth's Moon is very large compared to it's planet relative to every single planet in our solar system.

[@Cashman9111]

so jupiter would be a dwarf planet if it had a twin ?

[@robertjarman3703]

Dwarf planet is a term used to suggest that it would not be capable of clearing its neighbourhood of rival bodies. Pluto is much smaller than the overall cloud of things like it, and could not act to clear it all by ejecting them, drawing it into itself, making it a satellite, or have an orbital resonance. The Moon is big enough that if the Earth didn't exist, it would be capable of doing the same thing that the Earth does for the things between Venus and Mars, which the Moon is just as far from as Earth is. The Earth would be a planet regardless of what the Moon is classified as. The Moon is still always going along with the Earth in an obvious pair, always moving with it at basically the same speed and location around the Sun.

[@EvgenijGr]

The part of the video that shocked me the most was that you can put a code to produce a part of video inside your video editing software....

[@faeryelise]

The orbiting point being outside the planet is the case with Pluto and Charon, isn't it?

[@davidroddini1512]

Yes it is. Pluto and Charon are a binary dwarf planet system.

[@MarkusAldawn]

I believe it is also the case for the Sun and Jupiter, which showcases that even if one body is much more dominant than the other (unlike Plutocharon which is a much closer match), distance increases more quickly than mass can. I wonder how far away from the sun you'd need to put an apple for the barycentre of that system to be outside the sun.

[@pufthemajicdragon]

@@MarkusAldawn SO DO I NOW! So I asked Copilot lol Using the d = r*Mapple / Msun formula "So the apple would need to be more than 6.928×10^36 km away from the Sun. And, for reference, the observable universe is estimated to be about 8.8×10^26 km in diameter."

[@circle-of-5ths]

@@pufthemajicdragon now i wonder how long that orbit would take

[@Delibro]

@@MarkusAldawn So, Jupiter and the Sun are in fact a binary star. (Well, no, cus Jupiter is no star ...)

[@TF8ase]

That was really fascinating. Perspective is amazing.

[@palid11]

1:27 is it just me or the second one from the top / second from the left looks very much like the Mandelbrot set? 😮

[@Noobier]

It's actually is, it's a shape called a cardioid that can also be found in your morning coffee

[@KeppyKep]

This is brilliant (the video, not the sponsor). One of the best videos you've done.

[@kinexkid]

Is this the reason why the moon is slowly moving away from earth, because the moon can be described mathematically as orbiting the sun, just in a close proximity to the earth? Or is that purely explained by the interaction between the earth and moon and its loss of angular momentum?

[@tonywells6990]

That is pretty complicated, depending on lots of factors and the drifting has a complicated history. The Moon will stop drifting away from the Earth and will eventually end up about 50,000km further out than it is today at about 450,000km.

[@feynstein1004]

Eh loss of angular momentum would cause the moon to spiral inward, no? iirc it's because of the leftover energy from the Earth-Thea collision which formed the moon.

[@patrickskelly8517]

@@feynstein1004 The Earth is losing angular momentum by giving it to the Moon, so the moon is moving outwards. It's because the Earth is rotating faster than the Moon is orbiting, so the continents crash into the tidal bulge of the oceans every day and feel a little drag force every time, slowing the Earth down. In turn, the continents push the tidal bulge of the oceans a little ahead of where it should be, and the gravity of the oceans pulls the moon a little ahead in its orbit making it orbit faster.

[@tonywells6990]

@@feynstein1004 It's a great example of conservation of angular momentum. The Earth's spin slows down due to the tides, but the angular momentum has to be conserved, so it is transferred to the moon as an increase in orbital angular momentum. The Moon speeds up and orbits at a higher altitude.

[@TheDeliciousOne]

@@patrickskelly8517 It's worth noting that a higher energy orbit is actually slower, given that it's higher up. Astronauts actually ran into this problem during the earliest attempt at a rendezvous - trying to burn towards an object you're behind results in falling further behind as your orbit rises.

[@QuantumHistorian]

Yes, that's what changing frames of reference does - it makes things look different. Orbits are only circles / elipses (or even, strictly speaking, defined at all) in an ideal two body system when viewed from the barycentre. Add in anything else, and you get nested geometry. This has nothing to do with the Moon in particular, and there's nothing weird about it. At least, nothing weirder than if you plotted the motion of a yoyo that someone was playing with while on train from the point of view of the ground.

[@poruatokin]

You put it best at 4:07 when you said "futile endeavour" which really sums up this video.

[@wombat.6652]

But fun to watch someone trying :)))

[@BarteG44]

Nobody made you watch it

[@epremier20050]

to me, what cemented it for me that it's futile is when the 3 body problem is brought up there as it shows that very nature of the 3 body problem being a chaotic system is why it's non-deterministic

[@makibee2570]

The simple answer imo is that everything orbits everything. The shape that orbit takes is changes depending on mass and distance of nearby objects, but in the end, everything will still have some effect, no matter how small, on everything else

[@TheDanEdwards]

Earth's orbit around the Sun is also not a circle... because the Sun is moving, and very quickly (for human terms) around the galaxy, so Earth's orbit traces out what looks like a distorted sinusoidal wave. As do all the other bits of our solar system that are not really close to the Sun. So yes, *reference frames matter when discussing motion.*

[@billcook4768]

Depends upon how you measure movement. In terms of angular movement, the sun rotates around the center of the galaxy incredibly slowly.

[@Cogitovision]

Thanks for the clarification. Once again we find that language oversimplifies the represented universe, losing resolution and confusing understanding.

[@syedminhaj-ul-haque1982]

So moon cheated on earth

[@drybjed]

Hey, don't blame the sleeping satellite!

[@Penguinmanereikel]

Luna belongs to the streets!

[@JackFrost-rg3wv]

Right in it's face

[@K_End]

I mean the sun is pretty hot 😏

[@Flesh_Wizard]

These satellites ain't loyal😢

[@aoyuki1409]

i think the hill radius vs chebotarev radius describes my perspective on three body problems best. when one body has clear dominance over the other, and that other one has clear dominance of the third, at astronomical scale it can be simplified as two separate two body problems and be easily calculated to an acceptable accuracy. its when its unclear that who is the dominant and who is the recessive body makes the calculations extremely complex

[@T.h.e.T.i.n.o]

So its Just Orbiting Earth With Extra Steps

[@deadbeatSad]

"Well, yes. But actually, no."

[@davidroddini1512]

It’s just orbiting the sun with extra steps 😉

[@Relkond]

More like 'it depends on how you define orbit'

[@Mahawww]

The amount of work you all put into these short videos is beyond impressive! I just want to let you know that I deeply appreciate it and admire it!

[@deveshgarg7974]

Pls can anyone explain centrifugal part, how can earth be dominant when sun's pull is greater 3:17

[@Astronomynatureandmusic]

I get your question I think. You think that if the sun pulls harder than the earth, the moon would be leaving the earth and spiral towards the sun, right? The thing is, the sun pulls at the earth as well. This means the moon as well as the earth keep their orbit as they both also have a forward motion. I guess the moon will be a bit closer to the earth when passing behind it, and a bit further from earth when it's between the earth and the sun.

[@soyanshumohapatra]

When the moon is orbiting a centripetal force is required or you can say a centrifugal force is acted on the opposite direction

[@deveshgarg7974]

Let me rephrase, In inertial frame, Sun's force on moon is more than earth's force on moon. So the net force on moon towards sun In video he said in rotating frame, (somehow) earth's force is dominant. How come?

[@soyanshumohapatra]

@@deveshgarg7974 Because it is orbiting bro and an extra centripetal force is required to keep it in orbit

[@deveshgarg7974]

@@soyanshumohapatra yeah and that centripetal force is net resultant of sun's and earth's gravitational force, which comes out to be in the direction of sun

[@glengbh]

This is excellent. Delivery is excellent. Graphics are excellent. I feel grateful for your efforts.

[@sylnz97]

my entire life was a lie

[@joldent5333]

Best Minute Physics for a long time. This is amazing!

[@andrewchapman2039]

I got confused half way through so now I'm just going to assume the earth orbits the moon and be done with it.

[@timdelaney2798]

I just assume everything orbits me - though it does make the math tricky.

[@lehpares]

So refreshing having an old school MinutePhysics video.

[@alejrandom6592]

Babe wake up

[@PalaeoJoe]

It would seem to me that "moon orbits sun" and "moon orbits earth" are equally valid statements. The motion of an object must always be in reference to a reference point. So, depending on your reference point, either statements could be true.

[@dominikbeitat4450]

So, umm, given recent developments, I gotta ask, which one of Earth's moons are we talking about? 2024 PT5, or the other one?

[@patadamcek]

The Moon

[@Nonume]

Without the animations I would have never understood that concept! It was great! Its awesome that you took the time to make the graphs and animations to explain it! Could you explain two things that I could never fully understand? Why cant we point to the center of our universe If everything Is moving away from something and If the universe expanded from a dense point? They always say to imagine the expansion of the universe like a balloon, that every part of it is moving away from all other points. but They are all moving away from the center of the balloon right? The other thing Is that I cant visualize is how precession moved the path of the sun relative to the stars from our point of view. I get that our night sky changed because of It I just cant visualize how the path of the sun in our skies was different aswell.

[@Net_Flux]

3:36 They orbit the center of gravity of the earth-moon system, not the center of mass. Edit: Ok. I want to correct myself. They do rotate around the centre of mass. It's the centre of mass about which the resultant torque becomes zero for non-uniform gravitational fields, not the centre of gravity.

[@paulvansommeren]

What's the difference?

[@Net_Flux]

@@paulvansommeren Their coordinates are calculated differently.

[@enderyu]

Are you sure? If we ignore effects from the orbit around the Sun and change to an appropriate (inertial) reference frame, then the center of mass of the system will be fixed as per Newton's laws. Where would the center of gravity be relative to the CM?

[@riuphane]

Brilliant!!!

[@halfmv2]

To clarify for anyone thinking this changed their understanding of the moon orbiting the Earth: "Pulling each other" - the Earth pulls the moon a lot more than the moon pulls the Earth, thus when the moon goes behind the Earth from a heliocentric perspective, its not the Earth coming forwards but the Earth pulling the moon back. Yes there's a barycentre but that doesn't mean the moon is not orbiting the Earth. This is a classic 'reference frame' problem, and you can see this happening even with spacecraft launched to the moon (Artemis 1 DRO) where it appears to orbit the Earth and only nudged by the moon but from a lunar reference frame it perfectly orbits the moon. That's why these 3 body problems are more effectively solved in a rotating coordinate system. The moon is validly orbiting the Earth. Think about the moon's orbital plane shifted to polar, where it goes above and below the Earth and ahead and behind. That would then appear as if the moon is just slowing and speeding up when sideways to the sun and when facing the sun it would make a sinusoidal pattern. So, don't be confused by trajectories looking different in different reference frames, because whether the moon makes a spiral or square or hexagon it is always orbiting both the Earth and the Sun.

[@nateruns400]

That table of trajectories reminds of Spirographs. Loved those things.

[@_redniel_]

I think the moon orbits the sun because it used to be a part of an old planet, Theia, which, of course, orbited around the sun.

[@maxthexpfarmer3957]

????

[@lucasriddle3431]

"only 40% more distance" or "only 40% more massive", I gotta admit, don't sound like very minor changes to me, especially considering the distances and masses we're talking about.

[@kizmetmars]

Small correction at 1:25 The top row of trajectories is impossible since the satellite would impact planet.

[@davidroddini1512]

From what I saw they would be possible as long as the earth and moon were not in the same place at the same time. They’d probably have some pretty close calls though.

[@kizmetmars]

@@davidroddini1512 A binary system would work, like you say, where both objects move around the gravitational center. But not a satellite.

[@Nova_Theory]

For this school year I have a project of representing the orbit of the moon around the sun, I used complexe numbers in an equation on geogebra and I'm relieved to see that I got the same looking orbit as you. Thanks for your video !

[@mirage7436]

Correct me if I'm wrong. While this does make a certain amount of sense, it also assumes that the earth and moon were always orbiting on the exact same plane. So yes, this is one way of looking at orbits, but like so many things is only true "from a certain point of view."

[@glennac]

What’s the “point of view” you had in mind as an alternative?

[@mirage7436]

@@glennac As I said, this assumes they are on the same plane, which I don't believe to be the case. Looking at this and assuming that all the planets, etc are on the same plane in the top-down view is a good way to make very incorrect assumptions similar to people looking at a map and deciding the Earth must be flat.

[@Blox117]

they are in the same plane

[@Chilling_pal_n01anad91ct]

​@@Blox117moons orbit's plane is 5 degrees off.

[@TariosGD]

​@@Blox117If they were in the same plane there would be a solar eclipse every 4 weeks

[@BonesMcoy]

I love me some minute physics! The fact this video involves astronomy is even better! Thank you for still being around after all of these years and still educating!

[@lucidmoses]

4:18 take the lines you added away and we are back to looking the the moon orbits the earth. So yes it's a three body problem but only just. Hence in our day to day life we can ignore it and just go with the moon orbiting the earth.

[@Cleptro]

No way you just simplified what is, by definition, a chaotic system, to the point someone with NO background in maths or orbital mechanics can understand. Well done!

[@JanVerny]

I feel like the question is presented in a way where orbiting one object means you are orbiting exclusively that object. Whereas looking at just the pictures without any emotional flavor, we can clearly see that it is simply doing both at the same time. The moon orbits the Earth and it also orbits the Sun. Partially because Earth orbits the Sun, partially because everything within the Sun's gravity well orbits the Sun. There is nothing weird or somehow vague and uncertain.

[@DamirSecki]

WOW - what an intersting video - never ever thought it in this way ... completely new perspective while it all makes absolute sense... ..again, WOW

[@GrilledCheeseSandwichReal]

2:50 I think that you might be meaning to refer to the edge of the Hill sphere (or Roche sphere if you’re pedantic like me). To my knowledge the Chevotarev sphere has no application in this example.

[@coldfusion247]

If he meant Hill sphere, that also isn't correct as that is roughly 1.5 million km, and the moon is much closer than that, so not sure I believe this

[@GrilledCheeseSandwichReal]

@@coldfusion247either way it’s wrong, thanks for the help though!

[@RedSunT]

Note (to minutephysics): If you put notes on the screen that I need to pause the video to read, please put them a little bit away from the bottom, so that they don't get obstructed by the control elements of the video player.

[@willoughbykrenzteinburg]

Helpful hint : the space bar will pause/unpause KZbin videos.

[@RedSunT]

@@willoughbykrenzteinburg correct. the control elements that pop up when paused are still in front of the notes. how does space bar help with that?

[@guddabuggle7858]

So the moon orbits the earth when the earth orbits the Sun and the Sun pulls harder on the moon but according to the hill radius THE EARTH pulls harder on the moon. What I'm trying to conclude here is the moon orbits the Earth and the moon also doesn't orbit the Earth because it orbits the Sun. It's that simple.

[@camilo12369]

Could you please share the maths of it? Those graphs at 4:52 are lovely

[@tehyonglip9203]

4:23 nice Star Wars reference there

[@Ashish-wo4rs]

Finalllyyyyyyyy!!!!!! Missed this channel sooo much

[@IndiBrony]

I just want to point out the inaccuracies in this video. I'm rather annoyed that this video negated one massive detail which changes the complexity of this system as a whole, that is to say: how do you account for the huge gravitational pull from yo momma?

[@miles3101]

This video was great, I never comment on your vids mainly becaise they are short, butthis was very interesting to consider since I never really thought of how the orbital relationship would change with physics such as speed or distance. The two radiuses for the earth's gravity overpowering the sun was my favorite

[@Hermann493]

0:25 this animation is misleading. The moon orbits the earth ~13 times per year not ~4 times as shown here

[@austinheyman]

It was exaggerated to drive home the fact that it revolves slower than assumed by most. None of these animations are actually drawn to perfect scale…you couldn’t even animate the actual distance between the moon and the sun on a youtube video frame since it is so large of a distance (the moon would be invisible). It’s all for imagery in relation to the script. The script is key. You’re literally nit-picking the tiniest of “errors” that are not even errors.

[@jemmerl]

I nearly spit out my drink when the orbit speed abruptly ramped up 30x and they went haywire

[@Albertandearthie]

1 minute after video gang:

[@otzmaanalytics4679]

Very nice, but the reason the moon's orbit actually isn't a (smoothed) dodecagon is that the length of the solar year is not the same as the length of 12 lunar months. The two roughly sync up every 17 years, though. So, a better description of the shape of the moon's orbit is a 204-pointed star.