Double Planets

[@murderedcarrot9684]

If there was another garden planet teaming with life in our system, I imagine we would be more motivated to space exploration.

[@deker0954]

The Moon would have been ignored

[@floridaman4073]

It would have global warming too.

[@floridaman4073]

@@deker0954, probably not.

[@murderedcarrot9684]

@floridaman4073 it would have too. It's a garden planet. The double planet though, crazy geological activity, much wilder swings in climate and seasons because, not only is the two planets swinging eachother closer then away from the star, they're orbiting it so there's more variation in weather each year.

[@murderedcarrot9684]

How many orbits around eachother compared to one orbit around the sun? If the moon was another garden we would be very different.

[@maxwelllittle5291]

Imagine sapient life evolves on the side facing away from a tidally locked partner, only for some intrepid early explorer to look to the horizon and see the rising limb of another world.

[@itsfonk]

Well I for one am thankful we find ourselves conveniently situated on a generational planetary-sized arkship with a resource vessel nearby in-tow. Kinda neat how it all turned out so well for us… I’m also thankful for all of you likeminded individuals who share in this journey aboard our Earth. Be well everyone (:

[@MidwitObservations]

I agree with the earth ark ship. But it's not just the earth. It's literally the entire solar system, including the field barriers created by our earth and sun! Like force fields. Now we just gotta steer the thing.

[@PaulSpades]

@@MidwitObservations I think it's safe to say the sol fleet is going in the right direction and fast enough, since I don't know why we would want to head any other direction.

[@MidwitObservations]

@@PaulSpades if we put it all backwards on the galactic plain, then other stars would be super easy to travel to, as they would be going past us more frequently

[@PaulSpades]

@@MidwitObservationsyou're assuming going in reverse into incoming traffic, on the highway, has no negative consequences?

[@comentedonakeyboard]

Habitable double planets would make for a cool "cold war in space" seting.

[@danielschmidt2186]

Like the Dispossessed by Ursala laguine

[@berwynofgreyhawk5525]

Stupid human statement…. This is why we can’t have nice things

[@spawel1]

@@danielschmidt2186 great book

[@Because.Brandon.Photography]

The dedication you have cannot be overlooked. Thank you so much for all of the content

[@JasoTheRed48F2]

I woke up today with a flash hit of flu. I have been in a coma for the past 6 hours, I am dehydrated, I don't know who I am, I don't know where I am, all I know is that a new Issac Arthur video is up and I must watch it.

[@mnrvaprjct]

Even an episode on thanksgiving? Isaac is the man!

[@markchristiansen5683]

Arthursgiving!

[@averageviewer6286]

Indeed!

[@annoyed707]

His auxience is international, if not interplanetary, or interdimensional.

[@mill2712]

​@@markchristiansen5683 Arthur's giving.

[@MidwitObservations]

First year with the channel?!

[@rayceeya8659]

One of my favorite Anime is set on a Rochworld. Two planets with atmospheres that just barely touch. Two planets, Anatoray and Disith, are at war. They have technologically regressed and the world is very Steampunk with giant mechanical airships.

[@SlyRoapa]

Is it a rocheworld? The anime is pretty vague about the geography of things, the only thing that's clear is that it's weird. A rocheworld would make sense though.

[@fatweeb1545]

@@SlyRoapa I vaguely recall it being a space station whose inhabitants forgot about their origins but it's been over a decade since I watched it so I might be wrong.

[@rayceeya8659]

@@SlyRoapa It is hinted at with all the hourglasses hidden in the series but at the finale it's shown that Disith has been there the whole time, the Grand Stream was just hiding it.

[@priapulida]

"Last Exile" is the name

[@ravenlord4]

Season 3 of the Sci-Fi TV series "Lexx" had a double planet system with an air bridge between them. The inhabitants used hot air balloons to travel back and forth between the two planets. It was pretty cool :)

[@priapulida]

Foundation has a similar scenario with a species flying over to grase

[@kayakMike1000]

Oh... Lexx was really quite weird...

[@doug2424]

At midpoint you would be weightless in the book roche world the ocean on one of lobes tidally sloshed onto the desert lobe. Driving the weather on both lobes. The inhabitants feared that event.

[@CarlosAM1]

Oh hey, you re-made the "Double Planets and Rocheworlds" video. I personally have quite a softspot for that one, as it inspired some artwork I made a while back, so I was quite happy to read the title of this video. Great work as always isaac

[@codemaster2861]

Super interesting that tidlelocking is so dominatly distance based. Have you considered moving your reminder to like and comment in the video to after the get snack? Also the gravity hill was a cool concept id never heard of before this episode, keep up the good work!

[@Vjx-d7c]

Happy Arthursday Fellow Arthurians❤🎉

[@Eldagusto]

Hope the Arthur family had a lovely thanksgiving. This episode really makes me want to read that Roche world book.

[@therealanyaku]

Oddly enough, neither Mercury nor Venus is tidally locked. It would be interesting to explore the possibilities of non-circular orbits and resonant rotations, or for that matter, resonant orbits in objects near each other.

[@RodneyMeadows-k2s]

Great content, & the graphics were really neat! Great job!

[@bigjermboktown6976]

I've never been this early to a video! Happy Thanksgiving Mr Arthur and to everyone 🦃🌾🍂🍁

[@The_Foreigner_Belt]

This is the greatest sci-fi channel on the net.

[@Rage_Ironfist]

Im excited to see how long before Stellaris Gigastructures mod implements double planets. The mod author must be a fan of Isaac

[@isaacarthurSFIA]

There's even a Stellaris mod that used my voice for the computer notifications :) Which was fun to help make. I have it on unimpeachable authority that at least a few of the folks at Paradox / Stellaris are regular fans of the show.

[@Rage_Ironfist]

@@isaacarthurSFIA Haha, awesome. I will look it up

[@xXevilsmilesXx]

Noticed that as well 😅

[@dinoblaster736]

An alien culture that evolved on a double planet who be so interesting (not that alien's of other varieties wouldn't be)

[@yulu803]

Hi Issac, I have had this topic on my mind for a while now about mining on other planets. The formation of minable veins of various metals like copper, zinc and especially uranium here on earth is very much dependent on both active tectonics and water. An example is when plates submerge with high water content, the high pressure water is what moves magma streams upwards in this type of volcanism. Along the way as the water drops in temperature and pressure, they deposit some materials they "dissolved" from the crest and mantle. This forms minable deposits of various forms near the surface, with distinct areas of deposit for different elements. What would happen on venus, where presumbly the stagnant lid prevents continious tectonics, can these concentrated deposits still form near volcanic regions (if it had water to begin with)? Will mars have these minable deposits near the surface despite the lack of mantle activity? Potentially, predicting geology of Mars can have an impact on the direction of martian development, as if there's easilly accesible minerals it can really boost the econom early on.

[@christophergeorge8042]

Just to advocate for the sponsor, cell to singularity is actually one of the better incremental games out there!

[@Grim-Crusader]

Another reason to be thankful, IA videos ❤

[@Yoel_Mizrachi]

Double the planet, double the fun!

[@jimmiedmc1]

A new concept thank-you issac arthur

[@Jenab7]

Spindown time for a planet orbiting a star. t = ωa⁶IQ / (3GM²k₂R⁵) ω = planet's initial sidereal rotation speed, radians/sec a = the star-planet separation (or the primary-satellite separation), meters I = planet's moment of inertia For Earth, I = 8.038e37 kg m² Q = the planet's tidal dissipation factor Q = 13 for Earth Q = 50 for typical rocky planet (the usual default when planet's physical parameters are unknown) Q = 85 for Mars G = 6.6743e-11 m³ kg⁻¹ sec⁻² (CODATA 2018) M = the mass of the star (or the primary object causing the spindown of the satellite), in kilograms k₂ = the planet's Love number For Earth, 0.308 ≤ k₂ ≤ 0.353 R = the planet's radius, meters

[@malcolmt7883]

So, what time would be required to tidally lock twin Earths orbiting each other at the maximum distance of a million miles or so?

[@Jenab7]

@@malcolmt7883 about 3.6 billion years, with initial rotation periods of 12 hours, a=1.609344e9 meters, k2=0.308, Q=13, I=8.038e37 kg m², M=5.972e24 kg, and circular orbits around the center of mass for both planets.

[@malcolmt7883]

Thanks, that would've taken me a long time to figure out. @@Jenab7

[@francoislacombe9071]

There would be no super tides on such close double planets. Let me explain. The two bodies would be stretched quite a lot, that's true, but they would be tidally locked to each other, they would not be moving relative to each other, the tidal bulges would always remain in the same places on those planets surfaces. The gravitational influence of the star they orbit would probably make them wobble a little and produce _some_ tides, but nothing as spectacular as if their rotation and orbital periods were not synchronized.

[@nathanielmarquardt]

this man out here pumping out so many videos

[@stevef3274]

The Klemperer Rosette worked out just fine for the Puppeteers.

[@GruesomeSkunk]

I am absolutely blown away with the progress you've made with your speech therapy, honestly amazing! As someone with a mild speech impediment in lost for words, im super happy for you

[@murderedcarrot9684]

By the nature of patterns forming all possible patterns then repeating themselves, there's bound to be a carousel system of habitatable planets orbiting a star out there, or rogue gas giant. Maybe one deliberately made some 480 billion light years away.

[@darthmortus5702]

I am a very long time viewer, and it was exactly the original double worlds episode that drew me to Isaac's channel! I was just insanely curious what such systems would be like and I searched for them. Needless to say I found my answer and more on that video and I haven't stopped watching since.

[@digitalnomad9985]

"These will have major tides and tectonic activity". The level of such activity would depend not only on the mass and distance, but upon the eccentricity of the mutual orbit. A circular orbit would result in NO tidal motion relative to the planets, but they would be egg shaped with the "small end" of each egg facing the other planet.

[@baahcusegamer4530]

We have at least one double planet in our own solar system. We call it Pluto and Charon. The Earth-Moon system is close to being one too.

[@abystanderstandingby6769]

I remember that one episode of Miles from Tomorrowland where the characters explore a double planets.

[@xucaen]

I found this video to be the most interesting video I've seen in a very long time. My right hemisphere is all lit up! 😎♥️

[@BigZebraCom]

I typically order my double planets with cheese, no tomato.

[@digitalnomad9985]

Whenever I order with cheese, I always get a green moon.

[@BigZebraCom]

@@digitalnomad9985 that's a great idea!

[@Tinman97301]

What an intense thought project. This gives me hope for the future.

[@pyrobreather1]

I think a funny video would be one in this style but instead it's educating those on double planets about single planets and how life would be different.

[@bennort6035]

Hi Isaac, thanks for another amazing video! Where do you get the exoplanet animations and images from?

[@MR-vi9lm]

4 minutes since posted.... my personal best

[@planetdisco4821]

Ursula Le Guinn dealt with a double planet system in one of her novels “The Dispossessed”

[@patromo]

Happy Thanksgiving to you and your family Isaac

[@hubbletrubble7875]

8:15 A good line is the 1:25.14 mass ratio, where the L4 and L5 points stop being stable

[@halletts1171]

Isaac, I started watching you from the first season I think. With life, I haven't tuned-in in a while. Just to darned busy. After I retire in December I really need to go back and hit the like button on your videos. Love the future forward look and the weak force of gravity from being in in the Army, yes I remember your job in the military. Take care and hope to catch up with your videos soon.

[@Lngbrdninjamasta]

I really enjoyed this subject! Thanks u for producing this ❤

[@adirmugrabi]

according to the International Astronomical Union, double planets are called DWARF PLANETS!!! since they didn't clear their orbit! and this is why i hate them! PLUTO IS A PLANET!!!

[@lynettecarter9887]

Happy thanks giving my friends ❤️💯🎄🦦

[@SpaceTimeSorcerer]

As an Outer Wilds enjoyer, I enjoyed the Hourglass Twins.

[@timothybarrett7626]

Happy Thanksgiving Arthur

[@travisporco]

thanks for posting on the holiday! happy thanksgiving

[@H1Guard]

Isaac Asimov showed, ~60 yrs ago, that the Earth's gravitational influence on the moon is slightly less than the sun's (about 4% iirc).

[@mill2712]

21:05 Two planets approach the roahe limit.

[@Jasonmakesvideo]

This concept makes me think dichotomies and dualism

[@frankstafford1555]

Happy Thanksgiving. Thanks for the vid always enjoyable

[@patriautic9308]

Halfway in and I haven’t seen Rocheworld (Flight of the Dragonfly) by Robert L. Forward yet.

[@imsorryyourewelcome]

Hey, Isaac! At 16:30 you start speaking about the tidal forces of the pair of planets, but did not address whether or not this would even factor in if they were already tidally locked. If there are no tides because the same sides are always facing each other, then there would actually be less tectonic activity, right? This also begs the question: What happens to their magnetospheres if both planets are tidally locked? Do they even have them anymore? Do their cores die at a much faster pace?

[@SoloRenegade]

2 habitable planets on their own independent orbits while orbiting their star 2 habitable planets orbiting one another while orbiting a their star (Earth and Luna was nearly labeled such a system).

[@TAP7a]

First would likely be a horseshoe orbit, my favourite coorbital formation

[@SoloRenegade]

@@TAP7a or just like Earth and Venus

[@MrKIMBO345]

There were astronomical news about the first observership of double planet from the new space telescope. It was considered as a young process of new planet. This was rare.

[@MarcusMacgregor2]

Imagine if there were two life bearing worlds until one got too close to the Roche limit. The future paleontologists on the surviving world will have a heck of a time figuring that one out. Why are these fossils so big and weird?

[@patrickmchargue7122]

Thanks for the explanation of tidal locking. Now, if you could help me understand gravity assist to speed up a rocket - in what should be a conservative field - as clearly, that would be great.

[@isaacarthurSFIA]

Might be worth an episode :) Short form though: The planet and the ship flinging around it are conserving energy and momentum, it just tends not to be obvious that the planet in question lost some of its momentum.

[@doug2424]

Roche world I love it!! Happy Thanksgiving!

[@stuartjohnston7888]

This was enjoyable, brings back memories of several good Si-Fi stories.

[@Pheonix1328]

Reminds me of the movie "Kaena: The Prophecy". It isn't the greatest or most scientifically accurate, but I thought it was pretty cool at the time.

[@amazinghoffman]

I was just thinking about double planets the other day, You're on time as always!

[@alanhyland5697]

I actually had the game in my library already

[@floydlooney6837]

I have had a story universe in my head for decades and it included twin worlds, both habitable.

[@mikelfunderburk5912]

Happy Arthursday

[@elitemook4234]

Well, time to grab a drink and a snack.

[@PlanetXMysteries-pj9nm]

Science and the universe are something too sublime for me. Thank you for letting ignorant people like me see more of the universe. I really like this channel

[@sgalla1328]

I wish you , Issac , could answer three questions for me , even if it is theoretical.. 1. What set of circumstances could cause the earth to rock back and forth ? 2. What event could cause the sky to roll up like a scroll ? 3. What set of circumstances could cause the earth to be cloudy and not day and not night but in the evening light again ? Thanking you in advance.

[@isaacarthurSFIA]

You might have to clarify #2 a bit, a horizon rolling up would indicate you were on a spin-gravity world, Earth actually rocks back and forth as the moon orbits us, so a bigger or nearer one would make that happen more, especially if it were more cock-eyed relative tothe ecliptic and/or our equator. And for #3, if I'm understanding you right, maybe s tidally locked planet with a high albedo moon on a short 1-day orbit.

[@werre2]

in the game Elite Dangerous there are multiple double earthlikes found

[@maxwelllittle5291]

I immediately thought of Onderon and Dxun from KOTOR II.

[@ollllj]

We now know 2 extra-solar system with over 6 small solid planet candidates per single sun. One is a red dwarf with too much tidal locking. Kepler-385 one is not. We still mostly lack the tools to detect smaller solid planets.

[@arcadiaberger9204]

Stan Lee once had Doctor Strange swear by "the Seven Secret Moons!", and I wondered what those might be. I finally concluded they were: The five Lagrange Points The actual Moon itself and The Barycenter around which Earth and the Moon both orbit, which circles within our own world. Well, just a thought.

[@mihaip1179]

Does the 50 billion period until Earth gets tidally locked to the moon also take into consideration the fact that the moon is moving away from us?

[@Cartoonicus]

Where can I listen to a full version of the music from the closing credits in this video?

[@valsodar6723]

I give to comunity idea about hour length episode about multiplex star system and Theory speculative evolution solution for eyes. Its good ide to invite somebody who already have some biology background.

[@tiagotiagot]

Would the difference in gravity between the facing and opposite sides not be countered by the centrifugal force?

[@dominusbalial835]

Would a planet tidally locked with a black hole be habitable? Would it be possible to tidally locked with a naturally occurring blackhole without being torn apart? Would the accretion disc from a blackhole be able to provide lighting to sustain life or would it bombard and scour the survive free of life with horrific doses of various types of radiation?

[@ValtorVentures]

9:20 If Gravitational energies moving between Earth and Moon are huge, Can we use said energy somehow? 🤔 Or some other way to harness gravitational energy?

[@robertheinrich2994]

just a stupid thought: if the moon was formed a bit further away, it wouldn't be yet tidally locked. not really a problem if the moon was formed a bit closer to earth, earth would be tidally locked to the moon, essentially giving us really long days and nights (not as long as 14+14 days, but still). this could also mean that higher forms of evolution can't happen, as plants and animals have to survive that. in other words: this almost sounds like a great filter.

[@Yoel_Mizrachi]

I vaguely remember a Sci Fi novel set on earth billions years from now when earth is tidally locked to sun AND the moon and some giant space spider built a web of string between earth and the moon

[@anthonyalfredyorke1621]

Thanks Isaac, you make really interesting & enjoyable shows, education has never been so much fun , I love the shows you do with J.M.G . We send our love to Sarah & the little ones. PEACE AND LOVE TO EVERYONE ❤❤.

[@kayakMike1000]

Ooh... What would their atmosphere work out out like...

[@joshualeniger]

Can you imagine how much space travel would evolve if we were in a system like this? Amazing to think about

[@Dogtroll]

Is it possible to use the gravitational energy being exchanged between the Earth and the moon for energy production and should we try to use it, i.e. would it be safe?

[@PeterSwinkels]

What interests me is the notion that humanity could move to a neighoring habitable planet with 1960's tech.

[@TheRealMooHamHead69420]

OMG double planets all the way across the night sky!

[@DanielGenis5000]

Happy thanksgiving! On double planets too, America #1

[@isaacarthurSFIA]

Happy Thanksgiving Daniel!

[@winycentaur2540]

this video makes me want to see an inhabited double-planet so badly😩😩 imagine the views/evolutionary history😭😭 I also wonder if (assuming there's other intelligent life out there), intelligent life on double-planetary systems develops space-faring technology faster than a typical "intelligent" species.

[@stainlesssteelfox1]

Technically, the moon isn't. Issac Asimov actually demonstrated this in an article in the May 1963 issue of The Magazine of Fantasy and Science Fiction. Earth only exterts half the force on the moon that the sun does. This means the moon orbits the sun primarily, nad the Earth secondarily. If you plot out it's path around the sun, it's a distorted sine wave it never loops back on itself like a true moon would.

[@Moontanman]

Wouldn't tides depend on how far from circular their orbit around each other is? As for air sharing between them, think of a 10 bar atmosphere and two planets each about 12.5 times the mass of the the earth but 20,000 miles in diameter, surface gravity about twice earth normal.

[@ConnorAustin]

Here is fun hypothetical a earth save planet in the same orbit as earth but on the other side of the sun

[@SoloRenegade]

Space Battleship Yamato?

[@vidyaishaya4839]

It would be difficult for two planets to be exactly the same mass, so one would orbit the other, but if the barycenter would be far outside either planet.

[@slabrankle9588]

How about all those double planets JWST found in the Orion Nebula recently? They could all be life bearing Hycean worlds. Doubtful but who knows?

[@Quintarus1794]

Would mutually tidally locked bodies in perfectly circular orbits even have tides any longer? I feel like the forces are constant from a reference frame on either surface.

[@calvingreene90]

A balloon and barrel to another planet. The Romans could have done it.

[@BePositive1984]

Billions

[@Paulomedi]

Hooray! I'm early for an episode!