Venus is indeed retrograde, if very slowly. Uranus is actually very nearly sideways, but technically retrograde if you go by the slight angle of its axis.
In the first year of my PhD program in geophysics and space physics* (first week, actually), I learned the pronunciation used by planetary scientists is "YOO-ren-us". So now instead of saying "your anus," I just misspell it "Urinous" to be crude in my own way.
*Not bragging... I did not complete a PhD; I washed out after one year and became a software engineer instead.
Eris is the reason why Pluto got dropped from planet status— they are about the same size and their orbits alternate being closer to the sun. But Eris is twice as far away from the sun than Pluto. So what to do—make both a planet? Nah-drop Pluto to planetoid status and every other since found.
I don't know what amuses me more about the comments this time around: The people bitter about Pluto, or the people bitter about the fact that people are bitter about Pluto.
“This slow rotation is what you’d expect from a planet in the process of becoming tidally locked, so why hasn’t it happened yet?[…] The atmosphere […] behaves as a kind of liquid-like gas compared to the thin atmosphere of Earth. Because of solar heating, the upper layers of the atmosphere circle Venus every 4 days. At the surface level, this induces a viscous drag on the planet, working to speed its rotation. In other words, the thick atmosphere keeps nudging Venus away from a locked rotation.”
Mercury isn't tidally locked either but it has no atmosphere so why is that little ball of rock still spinning after 4.5 billion years? Takes 88 Earth days to orbit the sun but 59 days for one rotation on its axis.
Mercury is considered tidally locked. It has a 3:2 resonant tidal locking, which means it rotates 3 times for every 2 orbits. AFAIK, this is due the highly elliptical nature of Mercury's orbit.
Reading up on this, apparently the 3:2 resonance it's in is stabilized by the high eccentricity of its orbit. Interestingly, the eccentricity varies due to perturbations from other planets, and can sometimes become nearly zero. It is apparently therefore possible that mercury could have been in a *different* resonance (e.g. 2:1) in the past that was then destabilized by changes in the eccentricity, which is rather weird to think about. tldr eccentric orbit + perturbations = weird, I guess!
My patron God is Hades, Plouton, for which Pluto was named. I am extremely saddened that it was demoted. To remove it because it doesn't fit the current standards... it is more than sad. Hades always gets such a bad rap, and now shown further disrespect.
Well... The definition of dwarf planet is arbitrary and there are really 10 candidates of significance. They meet the criteria for "planet" in more ways than they don't. In fact, the only way in which they don't is that they are not the dominant gravitational force in their neighbourhood.
What this means is that if earth were flung out close enough to Jupiter that we lost our local dominance, we would lose our designation as planet. Either we'd become a moon, or a dwarf planet
The problem with this is that without the "must be the dominant force of gravity in its area" rule, we'd have 34 planets on our hands, including Pluto sure.. but also including others like Sedna, Eris, and more
It's way better in my humble opinion to have 8 planets rather than 34...
And yes if the Earth went around Jupiter it would indeed be a moon, that's right!
I imagine the ways they don't meet the criteria for planet that others do is why they aren't planets. Going kinda featherless biped with your planets otherwise.
The difficulty is that the difference between planets is effectively arbitrary. A gas giant like Jupiter and a rocky planet like mercury have very little in common, except that they're both gravitationally bound spheres. The sun has more in common with Jupiter than mercury. It comes down to size and relative gravity within their neighbourhood.
I have not checked personally as I lack access to the astronomy equipment to do so, but I am reasonably certain there is not a teapot orbiting perfectly midway between the Earth and the Sun. Orbital mechanics mean it would have a different orbital period, so if nothing else, it would need to be under constant acceleration from a source other than gravity.
A rogue planet. Do you know of a situation where this has occurred? To my knowledge, science has hypothesized the existence of rogue planets, but has yet to witness one.
The only reason Pluto was ever considered a planet was an assumed mass based on a faulty measurement of Neptune's orbit that implied that it was being affected by an unknown planet. Pluto wasn't even in the right position for it to make sense.
There still is a 9th planet affecting neptune. We just havent found it. When we found pluto they just assumed that was it and stopped looking. They started looking again when they demoted pluto.
That was what we thought was going on, which was why 'the search for planet X' was a thing. Later someone investigating it dug into the maintenance logs and found that one of the telescopes responsible for the initial assessment of Neptune's orbit hadn't been recalibrated after work was done. When that telescope's measurements were excluded, Neptune's orbital path suddenly aligned perfectly with what was expected without an unknown planet's influence.
Looks like Eris. Ceres is 257 million miles from the sun. Haumea 4 billion miles from the sun. Makemake 4,253,000,000 miles from the sun. Eris 6.3 billion miles from the sun.
Nothing says Pluto can't become a planet in the future. In fact, it might be inevitable. All we would have to do is to give it some help at clearing it's orbit and that would qualify it as a planet.
If you think of the model of the solar system as having an "up" and "down" (like a school science fair model) the Earth rotational axis is only a few degrees off center from being vertical (with a wobble, of course). The rotational axis for Uranus is only a few degrees from being horizonal, so its spin direction is based on the direction of its closest point to the sun. So if the axis shifted about 10 degrees it could cross over the horizonal boundary and the relative orbit would be different.
But the short answer is yes, if you look at that science fair model, it would appear to be spinning on a horizonal axis where everything else, including Venus which also spins in the "wrong" direction, is nearly vertical.
lapus
The frog, duh!
sigmatis
adjacentengels
zufallszahlen
ralphie84
Asteroid belt
cuttlefishsticks
My Very Efficient Mnemonic Just Screwed Up, No Pluto :(
For anyone who wants to remember the order of the planets while honoring Pluto's memory.
nevergoingtogiveyouupnevergoingtoletyoudown
Uranus is spinning the wrong way. It should be excluded from the list of planets. At least Pluto spins the right way.
hydrocarbon82
Something is wrong with Uranus. And I'm not just quoting your last intimate partner.
ThierryVernet
Finland is missing
malfunctionm1ke
Uranus is a silly place
bmg50barrett
Everyone: Spin!
Uranus: !nipS
AmazingA
Looks like Venus goes that way too.
EchoPMIM
Venus is indeed retrograde, if very slowly. Uranus is actually very nearly sideways, but technically retrograde if you go by the slight angle of its axis.
BIC777
lancell
celestedrake
https://www.youtube.com/watch?v=e3cDdGKqp8E
film888master9
Viva La Pluto
YippeeKayakOB
bigmuffin1
Nah there are no more PLANETS needed to be added
wildwestpb
Chimaeraxxxxx
Venus rotates backwards?
spartanatreyu
Its day is longer than its year. But it's all a matter of perspective anyway
IceWeaselX
Is this what they mean when they say Uranus is around back?
AceOfNines
In the first year of my PhD program in geophysics and space physics* (first week, actually), I learned the pronunciation used by planetary scientists is "YOO-ren-us". So now instead of saying "your anus," I just misspell it "Urinous" to be crude in my own way.
*Not bragging... I did not complete a PhD; I washed out after one year and became a software engineer instead.
SlyPhinleyTheFirst
Eris is the reason why Pluto got dropped from planet status— they are about the same size and their orbits alternate being closer to the sun. But Eris is twice as far away from the sun than Pluto. So what to do—make both a planet? Nah-drop Pluto to planetoid status and every other since found.
Alexap30
This is not the reason. Pluto hasn't cleared up his orbit as the biggest prevalent body, which is one of the 3 criteria to qualify for being a planet.
DumpsterSauce
Milk, milk, lemonade, around the corner fudge is made
Naemless
Where's Bajor with their 26-hour day?
IrrelevantIrrelevant
I don't know what amuses me more about the comments this time around: The people bitter about Pluto, or the people bitter about the fact that people are bitter about Pluto.
EchoPMIM
The correct answer is obviously "the puerile jokes about Uranus".
shorttaldutchguy
The gas giants with their zoomies..
Easykehl
Is Venus on its way to being tidally locked to the sun? Hang on, going to do a google.
Chouilste
If it was tidally locked, wouldn’t there be a significant band in the -30 / +30 degrees celcius at all time ?
Easykehl
“This slow rotation is what you’d expect from a planet in the process of becoming tidally locked, so why hasn’t it happened yet?[…] The atmosphere […] behaves as a kind of liquid-like gas compared to the thin atmosphere of Earth. Because of solar heating, the upper layers of the atmosphere circle Venus every 4 days. At the surface level, this induces a viscous drag on the planet, working to speed its rotation. In other words, the thick atmosphere keeps nudging Venus away from a locked rotation.”
HzZbVYAx77aoiuN9Zy
stubbornness
Brettnetuk
ESChapin
Mercury isn't tidally locked either but it has no atmosphere so why is that little ball of rock still spinning after 4.5 billion years? Takes 88 Earth days to orbit the sun but 59 days for one rotation on its axis.
Abacadaba
Mercury is considered tidally locked. It has a 3:2 resonant tidal locking, which means it rotates 3 times for every 2 orbits. AFAIK, this is due the highly elliptical nature of Mercury's orbit.
SinStar87
Too hot - net
MuonNeutrino
Reading up on this, apparently the 3:2 resonance it's in is stabilized by the high eccentricity of its orbit. Interestingly, the eccentricity varies due to perturbations from other planets, and can sometimes become nearly zero. It is apparently therefore possible that mercury could have been in a *different* resonance (e.g. 2:1) in the past that was then destabilized by changes in the eccentricity, which is rather weird to think about. tldr eccentric orbit + perturbations = weird, I guess!
Easykehl
https://www.universetoday.com/155547/venus-atmosphere-stops-it-from-locking-to-the-sun/
ShoopDeDoop
I don't get it. What's missing?
SomeDetroitGuy
Ceres.
SnowmanHitInTheFaceWithALackOfCreativity
This is a very obvious thing which I am also missing
BixbyConsequence
Someone's still hurting from Pluto's demotion.
SnowmanHitInTheFaceWithALackOfCreativity
Ohhh.. Pluto. Fuck
ShoopDeDoop
I don't think that's it. If it were Pluto that were missing, there'd be ~30 other things missing too.
airbreather
Context.
MoonRiverFrost
My patron God is Hades, Plouton, for which Pluto was named. I am extremely saddened that it was demoted. To remove it because it doesn't fit the current standards... it is more than sad. Hades always gets such a bad rap, and now shown further disrespect.
rbudrick
I know uranus is on it's side but doesn't it still spin the "same way" as all the others except venus?
MelodiousDissonance
The Russell's teapot of course!
rihani3
Either there is nothing missing, or there are potentially thousands of things missing. Learn to deal with it...
Zaranthan
(Psst. We're not actually upset. It's just fun to say stuff like "when I was your age, Pluto was a PLANET!")
dethloc
Well I am my age and Pluto will always be a planet damn it!!
iRecommendBooks
PLUTO WAS A DOG
notacobra
Well... The definition of dwarf planet is arbitrary and there are really 10 candidates of significance.
They meet the criteria for "planet" in more ways than they don't.
In fact, the only way in which they don't is that they are not the dominant gravitational force in their neighbourhood.
What this means is that if earth were flung out close enough to Jupiter that we lost our local dominance, we would lose our designation as planet.
Either we'd become a moon, or a dwarf planet
simsom4343
The problem with this is that without the "must be the dominant force of gravity in its area" rule, we'd have 34 planets on our hands, including Pluto sure.. but also including others like Sedna, Eris, and more
It's way better in my humble opinion to have 8 planets rather than 34...
And yes if the Earth went around Jupiter it would indeed be a moon, that's right!
notacobra
I've heard of this rule before, regarding 34 potential planets- NASA calls it planet earth rule 34
SinStar87
I imagine the ways they don't meet the criteria for planet that others do is why they aren't planets. Going kinda featherless biped with your planets otherwise.
notacobra
The difficulty is that the difference between planets is effectively arbitrary. A gas giant like Jupiter and a rocky planet like mercury have very little in common, except that they're both gravitationally bound spheres. The sun has more in common with Jupiter than mercury.
It comes down to size and relative gravity within their neighbourhood.
DinosaursCameFromSpace
There should be a teapot
shotty814
Zaranthan
I love the message, but that's not where the teapot is.
FoxPesdassi
Are you SURE? Have you checked?
Zaranthan
I have not checked personally as I lack access to the astronomy equipment to do so, but I am reasonably certain there is not a teapot orbiting perfectly midway between the Earth and the Sun. Orbital mechanics mean it would have a different orbital period, so if nothing else, it would need to be under constant acceleration from a source other than gravity.
PutYourFeetIntoTheRiver
What's with the teapot? I tried googling it and I found some cool stuff to buy. But pretty sure no answers to be found.
TheOneWhoWasLeft
It's Russell's teapot.
https://en.m.wikipedia.org/wiki/Russell%27s_teapot
DustyMcKnuckles
Why does only one dwarf planet get all the recognition?
What about Gonggong, Quaoar, 90377 Sedna, 90482 Orcus, Ceres, Makemake, Haumea, and Eris?
StellaMatutina
What about nibiru, home of the annunaki?
wherearemytesticles
Why do the planets have zip codes?
Hashbrown123
Because it should have been grandfathered in.
NotSomoneElse68
The toaster between us and Mars?
allcattywampus
'cuz FUCK 'EM–that's why!
iananimated
They know what they did!
BunchaCrunchOfHuman
Kukamunga, oingoboingo, Walla Walla, or Arnulf?
wurth
Make make? It that pinterest for plutonians?
MahadmaGaudi
Makemake?
JustDontCare
(Moai noises) https://en.wikipedia.org/wiki/Makemake
RalphH
Hail Eris! All praise Discordia!
Ricobe9
Probably because it shares a name with a cartoon dog
Grimmrog
Yes why send pics of them data and fancy stuff..
SilverNicktail
Pssst, Pluto was found by an American. That's the only reason there's a fuss over its classification.
PutYourFeetIntoTheRiver
Yeah. We don't care about that. It's a pretty little rock and crow brains like pretty little rocks.
bobbobbybobbington
What about all the other pretty rocks of equivalent and larger size?
pleaseconsiderthatImightbejoking
No. Most Americans don't know that it was found by an American.
Quebeker
Because it’s the only one that got demoted
kublaikhan
It wasn't demoted. It was just misidentified because it was so far away.
ProphetofEntropy
no, its just that one has stupid cartoon dog named after it so one had a cultural cache.
SomeDetroitGuy
It wasn't. That happened to Ceres first.
HappyTimeHollis
Ceres was demoted from planet status first. Also Vesta, IIRC.
HappyTimeHollis
And Pallas and Juno.
ESChapin
None of them got classified as planet for 76 years. They all went straight to other small classifications.
wodensday
What if instead of demoting Pluto, we promote all of ‘em
All the moons of Jupiter above the right size, too
Chaos reigns
DustyMcKnuckles
Show me the mnemonic device for that hahaha
Isthe4thtimethecharm
I agree, but really just because I don't have to go to school anymore. Fuck those kids.
badgesweedontneednostinkingbadges
Nope, planets orbit around a star. Moons orbit a planet. I good with calling anything in the asteroid belt or the Oort cloud a planet, though.
Nemacol
What do you call a “planet sized” object that used to orbit a star but no longer does?
badgesweedontneednostinkingbadges
A rogue planet. Do you know of a situation where this has occurred? To my knowledge, science has hypothesized the existence of rogue planets, but has yet to witness one.
license2kilt
And planets have cleared their orbit of other debris, the primary reason Pluto was reclassified.
badgesweedontneednostinkingbadges
Thank you, I did not know that.
DrLOAC
stinkingyeti
Now i have to watch it again
MisterLemons
HippoTel
DrLOAC
Yoink! That’s the version I was looking for.
Redyls
dmjalund
ThailandExpress
ImahumanIpromise
usedforceforsale
kunjava
Skevoid
The only reason Pluto was ever considered a planet was an assumed mass based on a faulty measurement of Neptune's orbit that implied that it was being affected by an unknown planet. Pluto wasn't even in the right position for it to make sense.
Talbotous
There still is a 9th planet affecting neptune. We just havent found it. When we found pluto they just assumed that was it and stopped looking. They started looking again when they demoted pluto.
Skevoid
That was what we thought was going on, which was why 'the search for planet X' was a thing. Later someone investigating it dug into the maintenance logs and found that one of the telescopes responsible for the initial assessment of Neptune's orbit hadn't been recalibrated after work was done. When that telescope's measurements were excluded, Neptune's orbital path suddenly aligned perfectly with what was expected without an unknown planet's influence.
AgentBunni
Nah Pluto knows it's hot shit and doesn't need that planet life. Tom Cardy told me so.
Avenkal19
They were just scared of adding Make Make, Eris, and the other planets.
StevenAlleyn
Ceres, Vesta, etc
KingXizor
Gotta add Ceres, Makemake, Eris, and Haumea if you want dwarf planets too.
mmontour
Fine with me. Let's do it.
MaddogDelphi1997
Which one is the furthest away from the sun?
MaddogDelphi1997
Looks like Eris. Ceres is 257 million miles from the sun.
Haumea 4 billion miles from the sun.
Makemake 4,253,000,000 miles from the sun.
Eris 6.3 billion miles from the sun.
Dasnekones
Nothing says Pluto can't become a planet in the future. In fact, it might be inevitable. All we would have to do is to give it some help at clearing it's orbit and that would qualify it as a planet.
fire0fear11
McTaco
Baby bouf?
fire0fear11
Tis true
dogfavoriter
Uranus is like that one wheel on the shopping cart
freshthrowaway1138
IIRC, it also lays on its side while spinning.
[deleted]
[deleted]
freshthrowaway1138
What? Wouldn't that mean it is 90 degrees from spinning like everyone else?
Snooj
If you think of the model of the solar system as having an "up" and "down" (like a school science fair model) the Earth rotational axis is only a few degrees off center from being vertical (with a wobble, of course). The rotational axis for Uranus is only a few degrees from being horizonal, so its spin direction is based on the direction of its closest point to the sun. So if the axis shifted about 10 degrees it could cross over the horizonal boundary and the relative orbit would be different.
Snooj
But the short answer is yes, if you look at that science fair model, it would appear to be spinning on a horizonal axis where everything else, including Venus which also spins in the "wrong" direction, is nearly vertical.
freshthrowaway1138
learning learning, always trying the learning.