Imagine the opposite. You live on a moon of a gas giant. You'd think it's nuts living without another closeby planet and just stare into the empty void
This is the best explanation on tidal locking and tidal forces that I have seen on internet and am always happy to go back if I forget something. Thank you Isaac!
I'll add to the chorus here; this is the best, clearest explanation of tidal locking that I've come across on RUclips. You are the first person to explain why the "bulge" is slightly offset, and how that causes rotational deceleration! Thank you!
+Isaac Arthur At the beginning of every video you reccomend CC do we can understand you. I just wanted you to know I van understand you perfectly without the CC. I have watched nearly all your videos already and am enjoying them immensely. Thank you for taking the time to post these.
I had trouble understanding him in the first videos, but i got used to his speech and now understands he easily, but i think the subtitles are good for the channel, many non native speakers can understand better, and other people can work upon his subtitles to translate to others languages easier.
+jpmmm333 Truth be told I didn't either till a few years ago when someone asked me to explain and I realized I wasn't sure, it's not a subject that comes up much even in physics.
@@isaacarthurSFIA WHAT IS E=MC2 is taken directly from F=ma, AS TIME is NECESSARILY possible/potential AND actual ON/IN BALANCE; AS ELECTROMAGNETISM/energy is CLEARLY AND NECESSARILY proven to be gravity (ON/IN BALANCE); AS the rotation of WHAT IS THE MOON matches the revolution. Consider TIME AND time dilation ON BALANCE. The stars AND PLANETS are POINTS in the night sky ON BALANCE. The diameter of WHAT IS THE MOON is about one quarter of that of what is THE EARTH. On balance, the density of what is the Sun is believed to be about one quarter of that of what is THE EARTH. Excellent. Consider what is THE EYE ON BALANCE. The TRANSLUCENT AND BLUE sky is CLEARLY (and fully) consistent WITH what is E=MC2. WHAT IS THE EARTH/ground is fully consistent WITH what is E=MC2. CLEAR water comes from what is THE EYE ON BALANCE. Notice what is the fully illuminated (AND setting/WHITE) MOON AND what is the orange (AND setting) Sun. They are the SAME SIZE as what is THE EYE ON BALANCE. Lava IS orange, AND it is even blood red. Yellow is the hottest color of lava. The hottest flame color is blue. What is E=MC2 is dimensionally consistent. WHAT IS E=MC2 is consistent with TIME AND what is gravity. What is gravity is, ON BALANCE, an INTERACTION that cannot be shielded or blocked. Consider what are the tides. The human body has about the same density as water. Lava is about three times as dense as water. The bulk density of WHAT IS THE MOON IS comparable to that of (volcanic) basaltic lavas on what is THE EARTH/ground. Pure water is half as dense as packed sand/wet packed sand. Now, the gravitational force of WHAT IS THE SUN upon WHAT IS THE MOON is about twice that of THE EARTH. Accordingly, ON BALANCE, the crust of the far side of what is the Moon is about twice as thick as the crust of the near side of what is the Moon. The maria (lunar “seas”) occupy one third of the visible near side of what is the Moon. The surface gravity of the Moon is about one sixth of that of what is THE EARTH/ground. The lunar surface is chiefly composed of pumice. The land surface area of what is the Earth is 29 percent. This is exactly between (ON BALANCE) one third AND one quarter. Finally, notice that the density of what is the Sun is believed to be about one quarter of that of what is THE EARTH. One half times one third is one sixth. One fourth times two thirds is one sixth. By Frank Martin DiMeglio
Wow, as an astronomy enthusiast all my life, i never heard the reason why tidal locking actually happened. I knew it was due to tidal friction, but no graphical representation like you showed. So it seems tidal locking is NOT an anomaly or random occurance, its actually a natural evolution of two orbiting bodies, they will always naturally strive to become tidally locked due to how simple physics of the tidal stretching works, correct? Quite interesting, completely changes how i always heard it described before. People and astronomers always say "oh, a tidally locked planet, how curious!", never actually mentioning that in fact, its the natural "desired" stable orbit that all bodies sloooowly drift to achieve. Nice. So basically one could argue that, planets with moons that are tidally locked, are "finished" in their mutual development (if we're applying a bit of gaming terms), while planets with moons that arent tidally locked, still has the same forces applied to gradually pull them into tidal locking, but it just hasnt had enough time yet. Before we thought binary stars were an anomaly, but turns out its the norm. (or is even trinary systems the norm?) Before i always thought tidally locked moons were an anomaly, but turns out its the desired natural progression of their orbits, if given enough time to complete the cycle.
Yes, dual-locking is kind of a finished state, though in such a case the two bodies will generally not stay the same distance, eventually decaying to crash into each other or fly apart, so not truly finished, though they will be locked while doing that.
Many videos just say that this happens, but don't give the actual explanation. It's like saying, an apple falls to the Earth because of gravity. Yeah, but why?? You enlightened the Why. Thank you so much for explaining this clearly, with simple visuals!
Cool! I kept finding videos explaining what tidal locking is, but I wanted to see an animation depicting the process of *how* it happens. This has perfectly answered my question. Thanks for posting.
Wow issac thank you so much! I always wondered why. You explained it in such a clear simple way. And also your voice is very nice and easy to understand, I dont think anybody will need captions.
Amagine a planet somewhere in the universe had a large moon that was tidally locked to the planet and the planet was totally locked to, and then a sapient species evolved on one side with that didn’t face the moon, and when they traveled to the other side of the planet, they saw a big glowing orb in the sky, they would probably say “What’s that up in the sky?”.
This is super helpful. I'm going to link to this video in the future when I explain tidal locking (and now I understand better just how it occurs! THANK YOU for the math chat, some of us enjoy that part!)
I really like how you showed the mathematical formula for time to tidal locking. Unfortunately most scientific you-tube videos lack any semblance of scientific rigor. Thank you for the video.
Thank you for providing the "out", so that there is a possibility that exo moons around gas giants may avoid, or at least delay, tidal locking by having atmospheres and oceans.
Wow, thanks Isaak for throwing that lifeline about oceans and atmospheres slowing the tidal locking phenomenon around closer planets and gas giants. So glad I viewed this one!
Really fascinating. I always knew there had to be more to tidal locking, but I didn't imagine this much. I'm quite pleased to have learned this! You explained it very clearly.
Issac, this video was tremendous. You made the complex simple and that is a real art. Thank you for taking the time to share your knowledge and make the world a better place!
Isaac Arthur you have a gift for it. Meanwhile, I was wondering why is it that that the bulge returns to center at the rate of one rotation per revolution. I suspect that's what the governing equations demonstrate but I'm curious about those dynamics?
Well the bulge itself is actually slightly off-center, like a valley trough you might leave if you pushed on a rubber wheel as it passed you, it take some time to flex back into place. What's happening is that the object is deformed a bit toward the object pulling on it, but the deformation is not quite symmetric as things sag back into place. That deformation, being off center, creates an asymmetric force in the opposite direction of spin, like a brake.
Forgive me if I don't understand, but how does it that this process described above, predictably result in planetary bodies ultimately reaching a steady state tidal locking rate of one rotation per revolution? What equations / laws of physics account for that natural phenomena?
The slower the body rotates on it own axis [relative to the other body] the less asymmetric force is acting as a break on it, less torque from the hump being off center. This drops to zero when one orbit and one rotation are of equal length.
This video is now going to be exhibit A in the argument of why the new open learning of the internet is probably one of the greatest human achievements. A complex phenomenon explained faster than I ate my snack!
"Key difference is that they aren't equally distant." This line appears in the written transcript at 5:58, but is not spoken aloud. I wouldn't have normally mentioned it, except that this passage definitely makes more sense with the line included. Anyhow, love the channel. Ciao.
Great video and explanation thanks Isaac. I was trying to explain it last night using a pizza tray as the earth and empty beer glass as the moon - and realised while knowing it existed also didn't really know why. I've subscribed to your channel and forwarded this link onto those I was trying to explain it to last night!
If you've not done so already, perhaps a good follow-up video would address the seeming transparency of the Moon when it waxes/wanes. Astronomers have noted for centuries that stars and other objects can be seen behind the Moon.
This guy's voice, Isaac Arthur - reminds me of a voice I've heard in a movie - somewhere, somewhen.... What's pinging my interest is the way he pronounces his 'R's at the ends of his words... I hope I'm not coming off as rude, I'm truly interested and things like this, for me, are worse than earworms, hahaaa! I came here to help my roommate understand tidal locking - about why we can only see one of our moon's hemispheres. I REMEMEBR! It was a voice used in the latest season of COSMOS, the animated parts, the history of major insights into the true nature of our reality - I'd have to search for which part and which person/discovery was the subject of the episode to find it, but I'm sure that it's in one of them.
One of your videos on hiding in-between stars got me thinking about how long other objects out there show tidal heat and for how long could that help mask a hidden part of a civilization. So i looked up how does tidal locking work. And my man Isaac Arthur #1 on the list. Your fuckin kick more ass than you realize sometimes. Good jod.
Pluto and Charon have that situation, where each one is tidally locked to the other. It's probably complicated by the fact that there are four additional moons in the system.
I'm a little confused by the ending saying the oceans and an atmosphere slow down the process of title locking. Does that mean that if earth was orbiting Jupiter it could maintain the same spin but with massive tides?
Congratulations on the wedding Issac, I have been watching since 2016 (about). So how long is our moon’s year? 28 days, same as it’s day? HUH? (How long is our moon’s day??) Or is our moon’s year 365 days? Thank you for all you and your team do .....SFIA FOREVER...
@Isaac Arthur question: What about when a Exoplanet is locked because its so close to its star that parts of it is stuck in perpetural daylight. Is that the same as Tidal Locking or is it something completly different (I'm reading Nguyen's apporixamation of the weather on K2-141B and the locked in place is confusing me
I have a question. This is the first time I've heard about the moon one day will only be seen on on side of earth. I've heard eventually, the moon will leave the earth's gravitational pull. So which will come first and how soon will each occur?
The moon's orbit is elliptical so the distance from Earth is not a constant. How do these equations work based on the apogee and perigee cycles? Thank you
So Many questions... Are all planets and satellites orbiting in the same direction? Do all planets and satellites have the same rotational direction? If either of the above occurs, how does tidal friction affect counter orbit? Can counter orbit/rotation cause the orbit of a planet or satellite to degrade such that it collides into its partner (?) ? It had never occurred to me before now, that a potentially habitable planet orbiting a gas giant would become tidally locked. Thanks, I'm learning. But what would happen to planetary conditions given that scenario, e.g. weather? One side arctic, one side desert and apocalyptic storms?
Sorry,question. are you saying that the earth and moon literally buldge as it spins??? if so then as the rotation of each occur the buldge of the objects would transfer constantly?? or is the buldge just a visual gravitational example?
do you know what the measurements are? im curious, they idea seems strange, I didn't think the earth and moon were so malleable. I get the part of the edge of each object having a stronger pull. Thanks!
A new patent I just read about, will allow space elevators to be built with current materials. It has multiple tethers at its center ( for greatest strength ) and fewer tethers as you move away from center ( for lesser amounts of mass ). Liftport has plans to build a Lunar elevator from current material. Using that same material for an Earth based elevator would reach the lunar gravity center (about 9,000 km AGL) approx. 1/6 G. Add this new concept and you could reach Earth's surface. We can do this now. Let's get started. What do you think?
I think this video would be a good candidate for a second pass with better microphone quality. It seems very quiet relative to your most recent videos.
Great video man, I really needed this explanation has I am working on a Sci-fi idea that involves a tidal locked planet. One quick question though if you got the time, is it possible to have a planet tidal locked to a red dwarf and then a moon that is also tidal locked to the planet. So you have planet locked to dwarf then moon locked to planet, that would be cool.
+Sagan L Glad you enjoyed it, I was going to recommend the tidally locked planets video to you to answer your question but it looks like you found it, though the third volume on Large Moons might be as applicable. I'm not sure if I mention it in either but the rule of thumb is that the distance from the planet to a sun must be at least nine times the distance from the planet to a moon for that moon to be stable. That wouldn't be an issue for any classic moon around anything but the smallest classes of red dwarf stars. ruclips.net/video/YRzJdg13geU/видео.html
Isaac Arthur Thanks for the quick reply, so if I understand correctly, the issue with a locked moon around a planet locked with a red dwarf would be the dwarf could be to close to the moon to prevent the moon from locking to the planet? If that would be the case could it instead be set up to where the moon does not revolve around the planet, that way if the moon was over the dark side of the tidal planet it would only be seen on the dark side and never on the light side, while the dwarf star was only seen on the light side? Hope my explanation makes since, sorry if it is confusing to follow. btw I have been binge watching your videos tonight, gives me tons of great insights for my sci fi worlds! :)
+Sagan L Lol, no problem, I usually reply to these inside 24 hours but I'm just finishing a video on moon bases so the text of your comment caught my eye.. For distance with moons, the closer it is to the sun the harder a capture will be, which is how planets get their smaller moons, big ones made by giant collisions might actually be more common, that's the sort of thing we could only check by massive supercomputer modeling and I don't recall anyone running that sim. To your question, *technically* its not a moon if it doesn't orbit the planet, but actually yes you could have a 'moon' that always stayed on the far side of a planet by being in its L2 Lagrange point. It would actually be another planet, but if it were at the L2 point it would keep pace with the mother planet rather than having a slower orbit like Mars does. So a moon a tidally locked planet's L2 would always be visible on the dark side of the planet, though L1 & L2 are not considered very stable places compared to L4 and L5 so it might be a stretch for a planet to have a moon there but it wouldn't be impossible, especially if it were actually in a Halo Orbit of L2, which might be a better option anyway since it would move (from the planet's perspective just a bit and not be totally blocked of sunlight.
Wow great, very well explained, and ya I realized after posting that a non orbiting moon would not be a moon after all but since it could be a smaller planet in the L2 range like you mentioned that would give me the same kind of effect I would be wanting and also like you said having the L2 object in a Halo orbit that way it could get some reflective light that could give a kind of "moon" lit light for the other wise totally dark side without the light side seeing the L2 object, at least not much if I followed the logic correctly. Thanks again for the all the help.
Clearly the atmospheric and oceanic lubrication of locking is a ratio of the air and water masses to the solid masses. Gas giants and water worlds will slip a lot, but I can't imagine a world like ours would very much.
Bro, I can't understand the Tidel lock between the earth and moon. I watched many videos regarding that but I can't believe that. Please explain this. My exact doubt is moon is also rotating itself, so somewhere we can see its front side and somewhere we can see its back side. Then how can be it tidel locked ?
@@valerierodger7700 Yes it does rotate. That's the whole point of this video. The rotation takes about 27 days, which is about the same time it takes to orbit the Earth. If you watch the video you'll see that the moon only shows us 1 side because of tidal locking (although we actually see about 59% due to orbital eccentricity, as explained in the video, again).
Wait... if a satellite and the primary body were both tidally locked to one another, wouldn’t they fall into one another? Wouldn’t that be the same as lifting a stationary plane of the ground and dropping it? Both the plane and earth are traveling at the same speed and thus “rotating” around the center of mass with the same velocity... meaning there frame of reference is the same. Zero difference in kinetic energy?
"...and materials take time to stretch and sag (2:00)." So am I to think of this "taking time to stretch and sag" like the moon's internal material having an elastic "spring rate"?
Hi Issac, i had a question about temperature differences. Say the earth became tidal locked with the sun. What would the temp range be on the light side and dark side? Thanks
Angular momentum and linear momentum are conserved in a closed system. May sound like perpetual motion but what really prevents perpetual motion is generally forces like friction. If you set a coin spinning on a table, it stops because of air resistance (friction with the air). Planets spin because they formed from a planetary nebula which had to have some angular momentum otherwise it would completely collapse in on itself. Some of that angular momentum is in the orbital motion around the star, some is in the rotation on the axis. There is almost no matter in space to cause friction on planets like air can on coins on earth, so planets continue to rotate and orbit freely. There are many more complications to orbits which I encourage you to learn about, it is a complex topic. If you want to learn more about perpetual motion I would recommend PBS SpaceTime's recent youtube video on the topic.
@@HighwayRamos I don't think they keep spinning at the same speed as outside forces are causing "friction" (not the correct word but hope you understand the analogy).
Very interesting ! However if energy is conserved when these gravitational forces transfer energy from the Earth to the Moon how can the the rotational velocity/energy of BOTH bodies reduce?...ie what happens to the lost Energy? I'm guessing that some of this energy gets transferred to heat energy when the bodies 'stretch' under these forces but maybe energy is also transferred to increased potential energy as the bodies get further apart?.Law of conservation of energy?
I've been looking for a video like this. Thank you! My only doubt is why the bulge is off center initially, I don't completely understand that, yet I understood the rest!
+thefran901 The bulge is off center because it takes time to sag back. If you just have two object stationary and fixed gravity will pull them toward each other and you get the bulge. But if you turn one that bulge isn't pointing toward the other object anymore and will begin slowly sagging back while re-emerging pointing toward the other object again. This sagging takes some time, so if the object is constantly spinning the bulge is always a bit off center, the slower the spin the less off center and thus less torque is generated to slow the spin until finally the bulge isn't off center anymore because tidal lock has occurred... it's very exaggerated in the video of course.
Hey man, I can't tell if an accent, pronunciation or hearing issue. All of which is irrelevant. I understand you perfect. I wouldn't spend to much energy worrying about it... Good work brohem
I have a question: Is it possible for something to be tidally locked to two other bodies at once, such as a planet and it's moon and parent star? I feel like it would be possible given the right distances (such as the planet being very close to the star and the moon being very far from the planet), and it could easily be done with a planet and twin moons (given that the moons are on the same orbital path), but it's not something I've given enough thought to.
So based off the information in this video is it safe to assume that given enough time every object in the universe that orbits somthingwill eventually become title locked with each other e.g. The moon is tidally lock to Earth an the Earth is tidally locked to the Sun
Yes - it's only a matter of time. Though, the Earth will become tidally locked with the moon; not the sun. The tidal forces from the moon are more predominant than those from the sun. This sounds counterintuitive, because clearly the sun's gravity is stronger. That is the case, but tidal forces are not really the result of the strength of gravity, but rather the variance of gravity across the same body. The Earth is about 12,750 km across, and the moon is only 384,400 km away. The strength of gravity depends on the distance to the source, so there are parts of the Earth that are over 3% closer to the moon than other parts. For the sun, 150,000,000 km away, this difference is not as extreme. Getting 12,750 km closer to the sun is only going to be about 0.0085% closer. In other words, the force from the sun is far more uniform across the Earth than the force from the moon is. Ergo, the moon creates more tidal forces on the Earth. This is demonstrated every single day : tides. The tides in the oceans on Earth are caused mainly by the moon's tidal forces. The sun does contribute to the tidal effects, but only minimally.
Wait a minute. AIUI, Newton believed he had pretty much the whole universe figured out (apart from that one thing that he attributed to god: all the planets moving in the same plane). At the same time, he has to have known the moon faces the earth, because you can see it with your bare eyes. So does that mean the tidal locking explanation of that was known already to Newton?
Imagine a culture growing up without the moon, travelling to a land where the moon could be seen.
I can imagine them being like “WHAT THE HELL IS THAT!!!”
@@colbyt2863 that’s no moon!
@@colbyt2863 That's god, obviously
Imagine the opposite. You live on a moon of a gas giant. You'd think it's nuts living without another closeby planet and just stare into the empty void
We now are arriving to the land of the moon
This is the best explanation on tidal locking and tidal forces that I have seen on internet and am always happy to go back if I forget something. Thank you Isaac!
I'll add to the chorus here; this is the best, clearest explanation of tidal locking that I've come across on RUclips. You are the first person to explain why the "bulge" is slightly offset, and how that causes rotational deceleration! Thank you!
+Isaac Arthur At the beginning of every video you reccomend CC do we can understand you. I just wanted you to know I van understand you perfectly without the CC. I have watched nearly all your videos already and am enjoying them immensely. Thank you for taking the time to post these.
You're very welcome Rene!
Thank you Isaac Arthur for those videos you upload, they are just awesome :)
Thanks Jargo!
Great vids dude and if anyone gives you crap tell the to f off your doing something they are not.
I had trouble understanding him in the first videos, but i got used to his speech and now understands he easily, but i think the subtitles are good for the channel, many non native speakers can understand better, and other people can work upon his subtitles to translate to others languages easier.
I spent 3 years knowing this happened but not exactly how just that distance was a factor thanks for this awesome and well done explanation.
+jpmmm333 Truth be told I didn't either till a few years ago when someone asked me to explain and I realized I wasn't sure, it's not a subject that comes up much even in physics.
@@isaacarthurSFIA WHAT IS E=MC2 is taken directly from F=ma, AS TIME is NECESSARILY possible/potential AND actual ON/IN BALANCE; AS ELECTROMAGNETISM/energy is CLEARLY AND NECESSARILY proven to be gravity (ON/IN BALANCE); AS the rotation of WHAT IS THE MOON matches the revolution. Consider TIME AND time dilation ON BALANCE. The stars AND PLANETS are POINTS in the night sky ON BALANCE.
The diameter of WHAT IS THE MOON is about one quarter of that of what is THE EARTH. On balance, the density of what is the Sun is believed to be about one quarter of that of what is THE EARTH. Excellent. Consider what is THE EYE ON BALANCE. The TRANSLUCENT AND BLUE sky is CLEARLY (and fully) consistent WITH what is E=MC2. WHAT IS THE EARTH/ground is fully consistent WITH what is E=MC2. CLEAR water comes from what is THE EYE ON BALANCE. Notice what is the fully illuminated (AND setting/WHITE) MOON AND what is the orange (AND setting) Sun. They are the SAME SIZE as what is THE EYE ON BALANCE. Lava IS orange, AND it is even blood red. Yellow is the hottest color of lava. The hottest flame color is blue. What is E=MC2 is dimensionally consistent. WHAT IS E=MC2 is consistent with TIME AND what is gravity. What is gravity is, ON BALANCE, an INTERACTION that cannot be shielded or blocked.
Consider what are the tides. The human body has about the same density as water. Lava is about three times as dense as water. The bulk density of WHAT IS THE MOON IS comparable to that of (volcanic) basaltic lavas on what is THE EARTH/ground. Pure water is half as dense as packed sand/wet packed sand. Now, the gravitational force of WHAT IS THE SUN upon WHAT IS THE MOON is about twice that of THE EARTH. Accordingly, ON BALANCE, the crust of the far side of what is the Moon is about twice as thick as the crust of the near side of what is the Moon. The maria (lunar “seas”) occupy one third of the visible near side of what is the Moon. The surface gravity of the Moon is about one sixth of that of what is THE EARTH/ground. The lunar surface is chiefly composed of pumice. The land surface area of what is the Earth is 29 percent. This is exactly between (ON BALANCE) one third AND one quarter. Finally, notice that the density of what is the Sun is believed to be about one quarter of that of what is THE EARTH. One half times one third is one sixth. One fourth times two thirds is one sixth.
By Frank Martin DiMeglio
Holy cow thank you so much, this was so much easier to understand that having to study wikipedia articles for days struggling to comprehend anything
Finally. That makes so much more sense when you explained there is "no dark side of the moon...just one we can't see." Thank you!
I'll add my voice to the chorus of thanks for this, the clearest and most tangible explanation of tidal locking that I've ever encountered!
Wow, as an astronomy enthusiast all my life, i never heard the reason why tidal locking actually happened. I knew it was due to tidal friction, but no graphical representation like you showed. So it seems tidal locking is NOT an anomaly or random occurance, its actually a natural evolution of two orbiting bodies, they will always naturally strive to become tidally locked due to how simple physics of the tidal stretching works, correct?
Quite interesting, completely changes how i always heard it described before.
People and astronomers always say "oh, a tidally locked planet, how curious!", never actually mentioning that in fact, its the natural "desired" stable orbit that all bodies sloooowly drift to achieve. Nice. So basically one could argue that, planets with moons that are tidally locked, are "finished" in their mutual development (if we're applying a bit of gaming terms), while planets with moons that arent tidally locked, still has the same forces applied to gradually pull them into tidal locking, but it just hasnt had enough time yet.
Before we thought binary stars were an anomaly, but turns out its the norm. (or is even trinary systems the norm?)
Before i always thought tidally locked moons were an anomaly, but turns out its the desired natural progression of their orbits, if given enough time to complete the cycle.
Yes, dual-locking is kind of a finished state, though in such a case the two bodies will generally not stay the same distance, eventually decaying to crash into each other or fly apart, so not truly finished, though they will be locked while doing that.
Really? So (Hubble constant aside), gravity always wins?!
@@isaacarthurSFIA Will this eventually happen to the earth and moon?
The moon is slowly drifting away
Great explanation! Was always a bit confused as why and how bodies become tidally locked, this cleared up a lot.
Many videos just say that this happens, but don't give the actual explanation. It's like saying, an apple falls to the Earth because of gravity. Yeah, but why?? You enlightened the Why. Thank you so much for explaining this clearly, with simple visuals!
Issac makes everything easy to understand and enjoyable
Cool! I kept finding videos explaining what tidal locking is, but I wanted to see an animation depicting the process of *how* it happens. This has perfectly answered my question. Thanks for posting.
DUDE!!! YOU SOUND SO DIFFERENT THIS FAR BACK! YOU ARE AWESOME, MAN!
“There is no dark side of the Moon just a side that we cannot see” was like really poetic
Wow issac thank you so much! I always wondered why. You explained it in such a clear simple way. And also your voice is very nice and easy to understand, I dont think anybody will need captions.
Thanks so much for this video! EXACTLY what I was looking for.
Great video Isaac. I like your style of explaination and the visuals. Keep it up!
Amagine a planet somewhere in the universe had a large moon that was tidally locked to the planet and the planet was totally locked to, and then a sapient species evolved on one side with that didn’t face the moon, and when they traveled to the other side of the planet, they saw a big glowing orb in the sky, they would probably say “What’s that up in the sky?”.
123 Easy Lesson on Tidal Locking. Nice.
This is super helpful. I'm going to link to this video in the future when I explain tidal locking (and now I understand better just how it occurs! THANK YOU for the math chat, some of us enjoy that part!)
Thank you. Wow. It’s so rare to see this well and simply explained.
I really like how you showed the mathematical formula for time to tidal locking. Unfortunately most scientific you-tube videos lack any semblance of scientific rigor. Thank you for the video.
This is the smartest 4 year old ever!!!! Good job buddy! 👍 proud of you!
Thank you for providing the "out", so that there is a possibility that exo moons around gas giants may avoid, or at least delay, tidal locking by having atmospheres and oceans.
Wow, thanks Isaak for throwing that lifeline about oceans and atmospheres slowing the tidal locking phenomenon around closer planets and gas giants. So glad I viewed this one!
Best explanation I have seen, well done - Thank you!
Idk why but i love your voice its so calming and happy sounding
Really fascinating. I always knew there had to be more to tidal locking, but I didn't imagine this much. I'm quite pleased to have learned this! You explained it very clearly.
Enjoyed the 'water' music, thanks for the upload.
Issac, this video was tremendous. You made the complex simple and that is a real art. Thank you for taking the time to share your knowledge and make the world a better place!
Thanks, I always want to do more of the short simple physics episodes like this one but don't seem to do it very often.
Isaac Arthur you have a gift for it. Meanwhile, I was wondering why is it that that the bulge returns to center at the rate of one rotation per revolution. I suspect that's what the governing equations demonstrate but I'm curious about those dynamics?
Well the bulge itself is actually slightly off-center, like a valley trough you might leave if you pushed on a rubber wheel as it passed you, it take some time to flex back into place. What's happening is that the object is deformed a bit toward the object pulling on it, but the deformation is not quite symmetric as things sag back into place. That deformation, being off center, creates an asymmetric force in the opposite direction of spin, like a brake.
Forgive me if I don't understand, but how does it that this process described above, predictably result in planetary bodies ultimately reaching a steady state tidal locking rate of one rotation per revolution? What equations / laws of physics account for that natural phenomena?
The slower the body rotates on it own axis [relative to the other body] the less asymmetric force is acting as a break on it, less torque from the hump being off center. This drops to zero when one orbit and one rotation are of equal length.
This video is now going to be exhibit A in the argument of why the new open learning of the internet is probably one of the greatest human achievements.
A complex phenomenon explained faster than I ate my snack!
Excellent video! Can't wait to see the rest on your channel.
excellent explanation thank you
"Key difference is that they aren't equally distant." This line appears in the written transcript at 5:58, but is not spoken aloud. I wouldn't have normally mentioned it, except that this passage definitely makes more sense with the line included. Anyhow, love the channel. Ciao.
This is the best ever definition, anyone can understand it easly, this is how all definitions need to be.
Best explanation for tidal locking. Thank you! I think I could explain it to someone else now.
Great video and explanation thanks Isaac. I was trying to explain it last night using a pizza tray as the earth and empty beer glass as the moon - and realised while knowing it existed also didn't really know why. I've subscribed to your channel and forwarded this link onto those I was trying to explain it to last night!
Great video! I had been wondering about this for the longest time!
Thanks Mike, one of the early ones on the channel but it seemed worth covering.
If you've not done so already, perhaps a good follow-up video would address the seeming transparency of the Moon when it waxes/wanes. Astronomers have noted for centuries that stars and other objects can be seen behind the Moon.
Thank you for explaining this. Understood you completely
Very illustrative video, thanks.
This guy's voice, Isaac Arthur - reminds me of a voice I've heard in a movie - somewhere, somewhen.... What's pinging my interest is the way he pronounces his 'R's at the ends of his words... I hope I'm not coming off as rude, I'm truly interested and things like this, for me, are worse than earworms, hahaaa!
I came here to help my roommate understand tidal locking - about why we can only see one of our moon's hemispheres.
I REMEMEBR! It was a voice used in the latest season of COSMOS, the animated parts, the history of major insights into the true nature of our reality - I'd have to search for which part and which person/discovery was the subject of the episode to find it, but I'm sure that it's in one of them.
One of your videos on hiding in-between stars got me thinking about how long other objects out there show tidal heat and for how long could that help mask a hidden part of a civilization. So i looked up how does tidal locking work. And my man Isaac Arthur #1 on the list. Your fuckin kick more ass than you realize sometimes. Good jod.
Thanks! Very easy to understand.
your video explains things very learly. thanks a lot
Thank you!! FINALLY it makes sense!! 😊
Thanks for this amazing explanation!
Pluto and Charon have that situation, where each one is tidally locked to the other. It's probably complicated by the fact that there are four additional moons in the system.
Good stuff! Thanks Isaac
I'm a little confused by the ending saying the oceans and an atmosphere slow down the process of title locking.
Does that mean that if earth was orbiting Jupiter it could maintain the same spin but with massive tides?
Thank you for the great video.
+Dave L Jackson Your welcome, glad you enjoyed it!
Good video straight to the point
Great video.
Fantastic video
Good video, Barry!
THanks for the video. Very interesting!
Wow. I never knew. Thanks!
Congratulations on the wedding Issac, I have been watching since 2016 (about).
So how long is our moon’s year? 28 days, same as it’s day? HUH? (How long is our moon’s day??) Or is our moon’s year 365 days?
Thank you for all you and your team do .....SFIA FOREVER...
I didn't believed when I saw your 7 minute video😊😊
thank you sir I greatly enjoy your videos
We can understand you very well!!
Great stuff. Thank you sir :)
Thanks now I know! And knowing is half the battle...
Great information for a layman such as myself. Cheers.
@Isaac Arthur question: What about when a Exoplanet is locked because its so close to its star that parts of it is stuck in perpetural daylight. Is that the same as Tidal Locking or is it something completly different (I'm reading Nguyen's apporixamation of the weather on K2-141B and the locked in place is confusing me
I have a question. This is the first time I've heard about the moon one day will only be seen on on side of earth. I've heard eventually, the moon will leave the earth's gravitational pull. So which will come first and how soon will each occur?
The moon's orbit is elliptical so the distance from Earth is not a constant. How do these equations work based on the apogee and perigee cycles? Thank you
So Many questions...
Are all planets and satellites orbiting in the same direction?
Do all planets and satellites have the same rotational direction?
If either of the above occurs, how does tidal friction affect counter orbit?
Can counter orbit/rotation cause the orbit of a planet or satellite to degrade such that it collides into its partner (?) ?
It had never occurred to me before now, that a potentially habitable planet orbiting a gas giant would become tidally locked. Thanks, I'm learning. But what would happen to planetary conditions given that scenario, e.g. weather? One side arctic, one side desert and apocalyptic storms?
Sorry,question. are you saying that the earth and moon literally buldge as it spins??? if so then as the rotation of each occur the buldge of the objects would transfer constantly?? or is the buldge just a visual gravitational example?
Well the bulge is terribly exaggerated in the episode but yes, the planet stretches toward the moon. It's quite measurable.
do you know what the measurements are? im curious, they idea seems strange, I didn't think the earth and moon were so malleable. I get the part of the edge of each object having a stronger pull. Thanks!
The Earth's crust doesn't bulge very much (about 1m) but the all water obviously does more.
en.wikipedia.org/wiki/Earth_tide
dude don't worry about your voice I think it's just fine!
A new patent I just read about, will allow space elevators to be built with current materials.
It has multiple tethers at its center ( for greatest strength ) and fewer tethers
as you move away from center ( for lesser amounts of mass ).
Liftport has plans to build a Lunar elevator from current material.
Using that same material for an Earth based elevator would reach the lunar gravity center
(about 9,000 km AGL) approx. 1/6 G. Add this new concept and you could reach Earth's surface.
We can do this now. Let's get started. What do you think?
Thanks for the explanation but I’m not to sure on the bludge theory.. I think there are some other forces at play as well.
awesome, i wish id seen that earlier
I've always thought the tidal locking of the moon was due to the moon previously being part of the earth. This makes much more sense :D
What are the unit associated with the parameters of you simplified time-to-tidal locking equation ?
5:54 the Earth's day was originally 12 hours long...
I know. 24 hours isn't enough alot of the time in my opinion
I think this video would be a good candidate for a second pass with better microphone quality.
It seems very quiet relative to your most recent videos.
Great video man, I really needed this explanation has I am working on a Sci-fi idea that involves a tidal locked planet. One quick question though if you got the time, is it possible to have a planet tidal locked to a red dwarf and then a moon that is also tidal locked to the planet. So you have planet locked to dwarf then moon locked to planet, that would be cool.
+Sagan L Glad you enjoyed it, I was going to recommend the tidally locked planets video to you to answer your question but it looks like you found it, though the third volume on Large Moons might be as applicable. I'm not sure if I mention it in either but the rule of thumb is that the distance from the planet to a sun must be at least nine times the distance from the planet to a moon for that moon to be stable. That wouldn't be an issue for any classic moon around anything but the smallest classes of red dwarf stars.
ruclips.net/video/YRzJdg13geU/видео.html
Isaac Arthur Thanks for the quick reply, so if I understand correctly, the issue with a locked moon around a planet locked with a red dwarf would be the dwarf could be to close to the moon to prevent the moon from locking to the planet? If that would be the case could it instead be set up to where the moon does not revolve around the planet, that way if the moon was over the dark side of the tidal planet it would only be seen on the dark side and never on the light side, while the dwarf star was only seen on the light side?
Hope my explanation makes since, sorry if it is confusing to follow. btw I have been binge watching your videos tonight, gives me tons of great insights for my sci fi worlds! :)
+Sagan L Lol, no problem, I usually reply to these inside 24 hours but I'm just finishing a video on moon bases so the text of your comment caught my eye.. For distance with moons, the closer it is to the sun the harder a capture will be, which is how planets get their smaller moons, big ones made by giant collisions might actually be more common, that's the sort of thing we could only check by massive supercomputer modeling and I don't recall anyone running that sim. To your question, *technically* its not a moon if it doesn't orbit the planet, but actually yes you could have a 'moon' that always stayed on the far side of a planet by being in its L2 Lagrange point. It would actually be another planet, but if it were at the L2 point it would keep pace with the mother planet rather than having a slower orbit like Mars does. So a moon a tidally locked planet's L2 would always be visible on the dark side of the planet, though L1 & L2 are not considered very stable places compared to L4 and L5 so it might be a stretch for a planet to have a moon there but it wouldn't be impossible, especially if it were actually in a Halo Orbit of L2, which might be a better option anyway since it would move (from the planet's perspective just a bit and not be totally blocked of sunlight.
Wow great, very well explained, and ya I realized after posting that a non orbiting moon would not be a moon after all but since it could be a smaller planet in the L2 range like you mentioned that would give me the same kind of effect I would be wanting and also like you said having the L2 object in a Halo orbit that way it could get some reflective light that could give a kind of "moon" lit light for the other wise totally dark side without the light side seeing the L2 object, at least not much if I followed the logic correctly. Thanks again for the all the help.
The day will come when Man will have to adapt himself to worlds like this.
Clearly the atmospheric and oceanic lubrication of locking is a ratio of the air and water masses to the solid masses. Gas giants and water worlds will slip a lot, but I can't imagine a world like ours would very much.
Bro, I can't understand the Tidel lock between the earth and moon.
I watched many videos regarding that but I can't believe that.
Please explain this.
My exact doubt is moon is also rotating itself, so somewhere we can see its front side and somewhere we can see its back side.
Then how can be it tidel locked ?
@@valerierodger7700
Yes it does rotate. That's the whole point of this video.
The rotation takes about 27 days, which is about the same time it takes to orbit the Earth.
If you watch the video you'll see that the moon only shows us 1 side because of tidal locking (although we actually see about 59% due to orbital eccentricity, as explained in the video, again).
Dr. Arthur, can you do a video on the rotation of Venus, as I understand it, it actually rotates in the opposite direction from the other planets?
But what about integral trees? I was hoping this would help me understand the integral trees.
Wait... if a satellite and the primary body were both tidally locked to one another, wouldn’t they fall into one another? Wouldn’t that be the same as lifting a stationary plane of the ground and dropping it? Both the plane and earth are traveling at the same speed and thus “rotating” around the center of mass with the same velocity... meaning there frame of reference is the same. Zero difference in kinetic energy?
"...and materials take time to stretch and sag (2:00)." So am I to think of this "taking time to stretch and sag" like the moon's internal material having an elastic "spring rate"?
Thank you for this! Thank you for narrating and not using a synthetic robot voice. It is very well explained and I feel woke.
Hi Issac, i had a question about temperature differences. Say the earth became tidal locked with the sun. What would the temp range be on the light side and dark side? Thanks
Why do planets spin to begin with ?
Conservation of angular momentum combining with gravity.
Good question. Also why do they keep spinning at the same same speed? Sounds like perpetual motion, which we are told is impossible.
Angular momentum and linear momentum are conserved in a closed system. May sound like perpetual motion but what really prevents perpetual motion is generally forces like friction. If you set a coin spinning on a table, it stops because of air resistance (friction with the air). Planets spin because they formed from a planetary nebula which had to have some angular momentum otherwise it would completely collapse in on itself. Some of that angular momentum is in the orbital motion around the star, some is in the rotation on the axis. There is almost no matter in space to cause friction on planets like air can on coins on earth, so planets continue to rotate and orbit freely. There are many more complications to orbits which I encourage you to learn about, it is a complex topic.
If you want to learn more about perpetual motion I would recommend PBS SpaceTime's recent youtube video on the topic.
@@HighwayRamos perpetual motion is not impossible. Motion that would be perpetual despite us robbing energy from it is impossible.
@@HighwayRamos I don't think they keep spinning at the same speed as outside forces are causing "friction" (not the correct word but hope you understand the analogy).
Does the YORP affect have any significant affect on this or is it just too weak at these scales?
Very interesting !
However if energy is conserved when these gravitational forces transfer energy from the Earth to the Moon how can the the rotational velocity/energy of BOTH bodies reduce?...ie what happens to the lost Energy? I'm guessing that some of this energy gets transferred to heat energy when the bodies 'stretch' under these forces but maybe energy is also transferred to increased potential energy as the bodies get further apart?.Law of conservation of energy?
I've been looking for a video like this. Thank you! My only doubt is why the bulge is off center initially, I don't completely understand that, yet I understood the rest!
+thefran901 The bulge is off center because it takes time to sag back. If you just have two object stationary and fixed gravity will pull them toward each other and you get the bulge. But if you turn one that bulge isn't pointing toward the other object anymore and will begin slowly sagging back while re-emerging pointing toward the other object again. This sagging takes some time, so if the object is constantly spinning the bulge is always a bit off center, the slower the spin the less off center and thus less torque is generated to slow the spin until finally the bulge isn't off center anymore because tidal lock has occurred... it's very exaggerated in the video of course.
+Isaac Arthur Thanks! Now I got it!
I wonder how one would explain this under Relativity?...
Are there tidally locked suns or galaxies?
Hey man, I can't tell if an accent, pronunciation or hearing issue. All of which is irrelevant. I understand you perfect. I wouldn't spend to much energy worrying about it... Good work brohem
Thanks.
I have a question: Is it possible for something to be tidally locked to two other bodies at once, such as a planet and it's moon and parent star? I feel like it would be possible given the right distances (such as the planet being very close to the star and the moon being very far from the planet), and it could easily be done with a planet and twin moons (given that the moons are on the same orbital path), but it's not something I've given enough thought to.
So based off the information in this video is it safe to assume that given enough time every object in the universe that orbits somthingwill eventually become title locked with each other e.g. The moon is tidally lock to Earth an the Earth is tidally locked to the Sun
Yes - it's only a matter of time. Though, the Earth will become tidally locked with the moon; not the sun. The tidal forces from the moon are more predominant than those from the sun. This sounds counterintuitive, because clearly the sun's gravity is stronger. That is the case, but tidal forces are not really the result of the strength of gravity, but rather the variance of gravity across the same body. The Earth is about 12,750 km across, and the moon is only 384,400 km away. The strength of gravity depends on the distance to the source, so there are parts of the Earth that are over 3% closer to the moon than other parts. For the sun, 150,000,000 km away, this difference is not as extreme. Getting 12,750 km closer to the sun is only going to be about 0.0085% closer. In other words, the force from the sun is far more uniform across the Earth than the force from the moon is. Ergo, the moon creates more tidal forces on the Earth. This is demonstrated every single day : tides. The tides in the oceans on Earth are caused mainly by the moon's tidal forces. The sun does contribute to the tidal effects, but only minimally.
Nothing is forever...
4:43 I'm not a math person, how to you quantify "u"?
Wait a minute. AIUI, Newton believed he had pretty much the whole universe figured out (apart from that one thing that he attributed to god: all the planets moving in the same plane). At the same time, he has to have known the moon faces the earth, because you can see it with your bare eyes. So does that mean the tidal locking explanation of that was known already to Newton?