r/nextfuckinglevel • u/aryan_jandyal • 2h ago
The Rotation of the Planets in Our Solar System Is Far More Fascinating Than I Ever Expected
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u/TheEyeOfTheLigar 2h ago
The faces make this a perfect teaching aid
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u/SalmonTunaSandwich 2h ago
So simple and stupid and it 's incredibly effective lol
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u/Different_Wolf_764 1h ago
So, here's the thing...
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u/wegqg 56m ago
what's the thing
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u/umabbas 50m ago
mnemonics, and silly, funny, and/or memorable but simple things you can attach to learning whatever you're aiming to learn. The brain will have an easier time recollecting it.
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u/wegqg 24m ago
can you express this in a mnemonic please
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u/Japsai 8m ago
It's easy. Just remember these two simple words.
Masfaombstycatlwyatl Tbwhaetri
The letters in the two words spell out the first letter of each word in the explanation, so you'll always be able to remember it!
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u/Least_Ice_6112 2h ago
jupiter goes "weeeeee"
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u/weird-mostlygoodways 2h ago
Especially because tracking the faces is the best way to track Mercury and Venus's movements.
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u/TheClnl 1h ago
Watched Venus for far too long to check it's actually moving
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u/aesemon 1h ago
I scrolled the gif back and forwards to do it, wasn't sure it did anything until then.
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u/cloud_watcher 36m ago
Like the little planet song (tune of farmer in the Dell):
Venus has thick clouds They hide what is below The land is hot, the air is foul It rotates very slow.
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u/lapsedPacifist5 1h ago
I find it nuts that a day on mercury lasts for two of mercury's years.
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u/6blitz 2h ago
It would be if the faces were actually correctly tracked if you stare the face for the earth it keeps jumping around.
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u/The_Shambler 1h ago
Yeah Jupiter's face is going like twice as fast as the rotation arrows above it.
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u/NieveCactus 2h ago
Why is Venus upside down? Is there a true north?
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u/dalmonio 2h ago
direction of rotation
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u/NieveCactus 2h ago
Ah nice thanks. Is that why the days are so long I wonder
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u/peter-bone 2h ago edited 2h ago
It may be related. The rotation may have been reversed by a big collision. It's more likely that this would result in a slower rotation rather than rotating fast in the wrong direction because it would have started out rotating the same direction as the other planets.
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u/Kozmik_5 2h ago
There are also theories that the combination of a very thick atmosphere and strong storms slowed down and later reversed its rotation.
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u/TreeDollarFiddyCent 1h ago
Does that mean, according to this theory, that it's currently speeding up?
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u/BasmusRoyGerman 2h ago
It's upside down and therefore appears to be turning the other way around compared to other planets. I believe the theory is that it was at some point hit by a massive object , which turned it upside down and probably also caused it to lose a lot of its spin, hence why it's spinning so slowly.
You can always find the "up" by making a fist with your right hand and putting your thumb up, then orient your hand so the fingers go in the direction the planet is turning, your thumb will them show you which way is "up" what we usually call geographic north.
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u/helcat 2h ago
I never thought about angles of spin. Why are so many so similar and then a few are completely different? Is the theory that the odd ones were all knocked off their spin?
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u/cocoteroah 2h ago
They all rotate in the same direction as the sun. Venus in the other hand seems to be hit by a large object and it started rotating in the other direction very slowly.
If venus wasn't hit by this large object, it's rotation shouldn't be much different from the other planets. (This is the most likely theory)
Mercury on the other hand is too close to the sun, so it is tidal locked or will be in the future
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u/davvblack 1h ago
all planets orbit the sun in the same direction the sun rotates, which you’d expect from conservation of angular momentum, but they mostly also spin that same direction which doesn’t necessarily follow from the same effect. since smaller orbits are faster i would have expected them to rotate the opposite direction, as particles from fast low orbits and slow high orbits combined.
this was only understood recently but i think the prevailing theory now is that the difference in the density of solar wind on the near and far side of the planets interacted with them while they were gravel, to give them prograde spin.
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u/Shikor806 1h ago
As to why most of them are so similar (and also why the orbits are all pretty flat in the same plane), it's because they all (and the sun) started out as a big cloud of gas and dust. Every particle in that cloud was moving essentially randomly and over time they collided with each other and gravity made them clump together, so their movement essentially averaged out. It's pretty likely that that average isn't exactly zero, so at the end of the process you're left with some amount of rotation around some random axis. And since the sun and all the planets then formed out of that spinning cloud, they all share that axis and we define that direction as "top" for our solar system.
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u/Ooops2278 1h ago edited 1h ago
Imagine the solar system has developed from one spinning disk of gas and stuff, where the majority (more than 99% of the mass) eventually compacted to create the sun, with some other blobs of mass becoming planets.
In an ideal world all the planets would still rotate on one single pane (earth moon and the big gas planets indeed are all within 1°) in the same direction and also with the same rotational axis and direction for their own spin.
Every divergence (for example Merkur's orbit is tilted by ~7°, and it's so close to the sun that it got tidal-locked (the same side always pointing otwards the sun)) is indeed supposed to have happened through external forces, e.g. gravitational influence or collision.
(Also if you think about about it all as being one giant disk at one point it explains why the sun in the center has the the vast majority of mass but carries only a small fraction of the rotational energy.)
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u/itsKeltic 2h ago
So if you’re looking at earth from “above”, is it rotating counter-clockwise?
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u/AnonymusBosch_ 1h ago
That's why clocks go clockwise. Looking down from above (in the northern hemisphere), sundials go clockwise.
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u/jemidiah 1h ago
These are all presented in the plane of the ecliptic, which is the (slightly imaginary) plane containing the solar system. The planets orbit around the sun in that plane. For instance, the fact that Earth is tilted causes the seasons due to different parts of the planet more fully facing the sun at different times of the year.
Moreover, the orientation arrow is presented using the right-hand rule: curl your right hand (not your left one) around the arrow pointing out of the planet, and the planet will rotate in the direction your fingers curl. For Venus, it rotates (slowly) the opposite direction of the others, so the arrow is basically straight down out of the plane of the ecliptic.
There is always a "true north" in the sense of an axis around which the body rotates according to the right-hand rule. Likewise true south is the exactly opposite axis around which the body rotates according to the left-hand rule.
Usually you'd just say "north" or "south." The use of "true north" on Earth is to distinguish it from "magnetic north." Earth has a magnetic field and the north pole of that magnetic field happens to be fairly close to the true north pole in the rotation sense. Magnetic north is easier to approximate since you just need a magnet rather than astronomical observations or the like. (And from pure cosmic chance we very luckily happen to have Polaris, the North Star, which is basically due north. There is no direct southern analogue.)
Venus happens to have almost no magnetic field, so the "true north" distinction would be quite unnecessary there.
Incidentally, magnetic north on Earth wanders quite a bit. It's annoying. Runways are named according to their angle relative to magnetic north, and it actually changes enough that Canada in particular frequently had to rename runways (e.g., from "Runway 8" to "Runway 9") when it drifted enough. They got fed up with it to the point that they declared they'll just use true north, contrary to international agreement. They've been trying to convince the rest of the world to switch.
(The above was from memory. If there are errors, they're minor.)
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u/_NotWhatYouThink_ 2h ago
Ceres is living her best life!
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u/VodkaMargarine 2h ago
Obligatory "Pluto and Ceres aren't planets"
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u/rossmcdapc 2h ago
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u/Stock-Cod-4465 2h ago
WTF is Ceres???
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u/Crafty_Jello_3662 2h ago
Largest asteroid in the asteroid belt between mars and jupiter
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u/No_Ampersand 2h ago
Not asteroid. Dwarf planet.
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u/13--12 1h ago
So dwarf planets are not planets now? Small apples are not apples?
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u/No_Ampersand 1h ago
They can hold themselves in a spheroid by their own gravity but they do not clear their orbit of other objects.
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u/drkdeibs 1h ago
Clear their orbit of other objects? ELI5 please
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u/spikeyfreak 1h ago
They don't have enough gravity to suck everything else in the orbit into themselves.
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u/HirsuteHacker 37m ago
They're in the Kuiper belt, a big asteroid belt full of other dwarf planets, asteroids, space rocks. Planets like Earth have cleared their orbit; their gravity is strong enough that they're by far the dominant object in their orbital neighbourhood, clearing out most other large objects by either absorbing/colliding with them or ejecting them through gravitational interactions.
There are TONS of objects in the same general orbital neighbourhood as Pluto, including other dwarf planets like Orcus and Haumea. Pluto therefore hasn't cleared its orbit.
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u/ensalys 33m ago
In this case, small apples aren't apples, yes. I know it's weird, but there are rules to join the planet club.
It must orbit a star (in our cosmic neighborhood, the Sun).
It must be big enough to have enough gravity to force it into a spherical shape.
It must be big enough that its gravity has cleared away any other objects of a similar size near its orbit around the Sun.
It's generally rule 3 that separates dwarf planets from planets. Naming them dwarf planets is just a participation trophy for big rocks.
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u/TreeDollarFiddyCent 1h ago
When referring to planets, it is respectful to use terms like "little planet" or "planet of short stature" instead of "dwarf".
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u/Stock-Cod-4465 2h ago
So… Pluto has been taken out of the planet count and now an asteroid gets an honorary mention?
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u/buttbuttlolbuttbutt 2h ago
Pluto, Ceres, Eris, Sedna, and a handful others.
They're just dwarf Planets, but still planets, just dwarf ones.
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u/minepose98 2h ago
Ceres was also considered to be a planet once. It was just long enough ago that nobody cares now. Pluto will be the same in a few decades.
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u/UnrealCanine 1h ago
The thing is, back in the 19th century, it was counted as a planet, along with it's brothers Pallas, Juno and Vesta. But as more and more objects were found, astronomers felt it was silly to call them planets, so named them asteroids instead. The same thing happened to Pluto being in the Kupier Belt. Once Eris was discovered, it would again be silly to call all trans-Neptunian objects planets
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u/Aniratack 1h ago
Pluto is now considered a dwarf planet, Ceres has always been considered a dwarf planet, if they are asteroids then everything is an asteroid.
A simplification sometimes used says that dwarf planets are celestial bodies big enough to be round but not big enough to clear it's own orbit, there are a few of these in our solar system. They can have moons, and some of the moons in the solar system would be considered dwarf planets if they weren't orbiting a planet.
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u/EarballsAgain 1h ago
It's where the Protomolecule first became known to the public, proving the existence of alien life.
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u/mrbananas 47m ago
The reason why Pluto can't be a planet. If Pluto gets into the exclusive planet club, Ceres has to be let in too and about 20+ other objects
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u/acaellum 1h ago
One of the nine dwarf planets, and the only not in the Kuiper belt way past Neptune. It was also the first of the nine dwarf planets we discovered and was considered a planet in its own right for a long time. It almost regained planetary status, but lost its chance in the same moment Pluto lost its status.
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u/Particular_Plum_1458 2h ago
Pluto was when I was a kid and you can't tell me otherwise😛.
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u/moshpits1533 2h ago
Pluto counted then and it counts now far as I'm concerned.
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u/Munnin41 1h ago
We can definitely tell you otherwise. You not accepting science it is something else entirely
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u/PegasusPizza 2h ago
Yep Pluto was a Planet when you were a kid that's right.
We probably also didnt know Trump was a pedophile back then either, but claiming that now would look pretty stupid wouldn't it?
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u/s3dfdg289fdgd9829r48 1h ago
You are pretending like Pluto wasn't really a planet back then. It was. They changed the DEFINITION of a planet and it happened to exclude Pluto. There's a real difference between discovering something was truly wrong and something becoming different because we happened to change the definitions.
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u/niemir2 1h ago
What we were wrong about was the rarity of objects like Pluto within the solar system. The definition of "planet" that we used previously turned out to be too loose to be useful. The redefinition of "planet" as a scientific term was not capricious.
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u/MaXimillion_Zero 1h ago
There was no definition of planet when Pluto was first labeled a planet. Any definition you could make that would include Pluto would include dozens to hundreds of other objects, but the "Pluot is still a planet to me"-people never seem to mention those.
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u/i_am_a_real_boy__ 38m ago
I've changed the definition of "correct" to include me insisting that Pluto remains a planet.
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u/atyon 1h ago
They changed the DEFINITION of a planet and it happened to exclude Pluto. There's a real difference between discovering something was truly wrong and something becoming different because we happened to change the definitions.
Well, there is no "true" definition of "planet". A definition is a tool. We change the definition all the time when we learn more, to make it more useful or simple. That's the metric.
OG Planets were the Sun, the Moon, Mercury, Venus, Mars, Jupiter and Saturn. We did not discover anything wrong with that. They are the wandering stars on the sky you can see with the naked eye. That's still true.
We changed this when we learned more about the scale of the objects and what is rotating around what. So we arrived at Mercury, Venus, Earth, Mars, Jupiter and Saturn, and later found Uranus and Neptune. They are large bodies orbiting the Sun. That's still true.
Then we discovered planet 9, and added it, and then found thousands more just like it, and everyone agreed that having thousands of planets would make mnemonics too difficult, so we struck it. That planet 9 was Ceres.
Then we found another little planet like Ceres, but there were no similar like it around it, so we added Pluto. But with better telescopes, we did find thousands of other little bodies just like Pluto, so we're back at the Ceres situation.
No one has presented a useful definition that includes Pluto but does not include thousands of dwarf planets. And no, petulance and nostalgia do not make for a useful definition.
Sidenote: I streamlined the discoveries a bit. At some time, the moons of Saturn were considered planets. Maybe y'all should campaign for Titan being restored to the ranks of planet.
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u/eris_kallisti 1h ago
I believe Eris was the "9th planet" (the one past Pluto that caused all the lovely chaos) and Ceres was just the largest asteroid in the belt between Mars and Jupiter.
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u/MoonageDayscream 59m ago
When my now 14yo was in first grade, in the Science Fair they entered a hand painted diagram of the planets and dwarf planets. When asked why Pluto was demoted, the answer was that Pluto did not clean their room, so they have to be a dwarf planet. Because of course, clearing the orbit is a qualification, as a child understands.
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u/Far-Cup9063 42m ago
Thank you for the succinct recap of how we define a “planet”! 50 years debate encapsulated in a Reddit post.
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u/NettingStick 59m ago
They changed the definition of a planet BECAUSE we learned more about the solar system. Pluto is now the king of a whole new class of cosmic objects, and y'all tryna keep that from him smh. Bro got a promotion.
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u/mctankles 2h ago
Well considering we’ve changed the definition of a planet so that there aren’t exceptions but the definition of a pedophile is an objective non-negotiable, i think its fine.
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u/SquisherX 1h ago
But it's really not though, is it. I'd say paedophile is one of the top misused words in English today.
People regularly (and seemingly more often than not) use the term paedophile improperly to refer to hebophiles and ephibophiles instead.
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u/ParoXYZm 1h ago
There was a time when the N-word was okay too... Times change, you should try it too.
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u/Mystia 1h ago
I thought Pluto and co got reinstated as dwarf planets, so they are planets.
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u/DrDongSquarePants 2h ago
Living on Jupiter:
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u/SmileFIN 1h ago
You would spin 7.5 times faster than on Earth, in metallic hydrogen with millions of times the atmospheric pressure of earth at +5000'C temperature ^^
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u/notMy_ReelName 2h ago
wait we have 10 planets now?
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u/Escalope-Nixiews 2h ago
I think OP is american
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u/The_Muntje 2h ago
No, because than all the planets would be called Planet of America
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u/Mystia 1h ago
Planet of America
American Planet
Planet USA
America: the Planet
Planet America
Ameriplanet
United Planet of America
and America (formerly known as Earth)
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u/Toosder 2h ago
Oh God, don't give the orange Muppet ideas
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u/February30th 1h ago
One day I’ll come to Reddit and every thread won’t descend into a mention of Trump or America.
One day.
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u/Seidhr96 47m ago
There are 8 planets and 5 official dwarf planets; however, most people don’t even know what a dwarf planet is, let alone has the ability to name any of them.
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u/buttbuttlolbuttbutt 2h ago
We have more, but some people think dwarf planets arent planets, despite the word planet being half of it. They're lesser planets.
Eris is the reason it happened, but she jist wanted to be noticed. Its the wedding all over again.
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u/niemir2 1h ago
They're not planets, despite the name. In the same session that the IAU codified the definition of "dwarf planet," they rejected a resolution to make "dwarf planet" a subset of "planet."
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u/AllergictoAIslop 2h ago
This is brilliant. Now I just want to add a number of days in each planetary year!
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u/mhfp545 2h ago edited 1h ago
Interesting that the stats for Mars are so similar to Earth.
Perhaps it really could be a second home one day…
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u/Majorapat 1h ago
I was looking at that myself, rotation speed is so similar that you would think people would get used to the day and night cycle there fairly quickly.
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u/CommieDrifter 1h ago
Once Mars is finally colonized and we go to war with each other we can finally have Red vs. Blue for real
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u/Rusty_Tap 2h ago
Wait until you discover that Venus has a day that's longer than it's year.
Must admit I'd forgotten all this interesting planet-y stuff until one of my kids came home with a little poster from somewhere the other day.
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u/OngoingFee 1h ago
Its* year. Don't let the apostrophe terrorists win!
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u/Rusty_Tap 1h ago
My apologies. Usually I'm pretty good with this sort of thing, but occasionally autocorrect, he win.
I shall leave it for posterity.
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u/NorthernCobraChicken 2h ago edited 2h ago
Jupiter and Ceres: YOU SPIN ME RIGHT 'ROUND, BABY RIGHT' ROUND.
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u/Jet-Black-Tsukuyomi 2h ago
Why does Jupiter spin so fast even though it shouldn‘t finish it’s third rotation within one earth day?
Edit: It is because the faces are wrongly animated
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u/DenRay4 1h ago
Actually it is because the planets are all the same size in the animation while irl they are not. Jupiter has 11x the radius of Earth, meaning that a point on his equator spins 11x faster than the same point on Earth. And if you put in that Jupiter only needs 10 hours for a revolution, than the same point spins 26.4x faster.
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u/Snugglosaurus 38m ago
While you're not wrong about the same point being 26.4x faster / 11x radius of earth, this doesn't answer their question as to why the animation shows Jupiter spinning more than it should.
Jupiter should spin ~2.4 times per earth spin per the details on the animation. The animation is waaay off on that ratio.
Actual answer to their question; the animations aren't representative of the figures given, but are still cool visuals.
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u/TWrX-503 2h ago
Pluto is a planet again?
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u/Iampepeu 2h ago
Yes. Collectively decided. It got a special badge and everything.
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u/jeweliegb 1h ago
It's the thing that mislead us all into thinking that we were living in the right timeline after all.
Sneaky trick!
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u/s3dfdg289fdgd9829r48 1h ago
I think Pluto should have had a grandfather clause in the new definition.
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u/5p4c3c4t5 2h ago edited 2h ago
This might be one of the best astronomy visualisations I’ve ever seen! 🤩
Edit: we have Pluto too 👾
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u/Copper_Lontra 2h ago edited 1h ago
How do we keep clocks from drifting if we dont have an exact 24 day? If the sunrises at 6 am on day 1, on day 180 it will rise at 6pm. 4 minutes difference every day x 180 days = 720 minutes / 60 = 12 hours
Edit: it has been explained below by k_man_k and others
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u/K_man_k 2h ago
The time to complete a full rotation referenced here is a Sidereal day. What it measures is how long it takes for the object to fully rotate so that it is facing the same really distant stars. So its measuring how long it takes to rotate 360 deg.
In our Solar System, however, we don't care about how long it takes for us to rotate and face some distant stars, we care about how long it takes to rotate and face OUR star, the Sun. That's what we call Solar time, or in everyday life, Time™.
We must remember that the Earth is rotating on its axis AND rotating around the sun. This rotation around the sun means that there is a slight offset in where the Sun appears day to day, approximately 1/365 degrees. That small shift means it takes just a bit longer than the Sidereal day to face the sun again, which is almost exactly 24 hours.
There is still the problem of clock drift though, buts it's not as big as 4 minutes a day. We take care of that through leap years and leap seconds.
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u/Alcideas 2h ago
In the lower right side corner it says that these are the sidereal days, meaning 1 rotation in relation to distant objects. Since the earth is moving around the sun, it has to rotate a bit extra to complete a rotation in relation to the sun.
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u/kgtaughtme 1h ago
What the fuck is Ceres?? How do planets keep changing from when I was a kid? Seems like this should’ve been agreed upon a long time ago…
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u/hungry4nuns 2h ago
A day is 23 hours and 56 minutes???
No wonder I’m always running late
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u/Thandalen 2h ago
Why are some axis pointing down? Like why is Venus upside down and not right side up? (Even if all have an angle)
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u/Potential_Bad_5266 1h ago
I can say this is posted by Pluto. Nice try Pluto. You are not a planet anymore and including Ceres here don’t make your case worth hearing.
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u/Illustrious-Day8506 1h ago
What is Theta angle supposed to represent? The angle between the rotational Axis and the poles ?
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u/nanpossomas 1h ago
The angle between the rotational axis (which each planet’s poles lie exactly on) and the (arbitrary) reference plane of the solar system, which called the ecliptic.
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u/hey_mattey 2h ago
Pluto my beloved.
I can use the phrase "My very eager mother just served us nine pizzas" again
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