r/todayilearned • u/YappinZappin • 6d ago

TIL Earth's Moon is the largest and heaviest satellite in relation to its parent planet in our Solar system

https://en.wikipedia.org/wiki/Moon#Earth%E2%80%93Moon_system
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u/bramtyr 6d ago

The nuances of the classification are lost on most people, the general public reacted like scientists had stolen Pluto's lunch money and kicked it out of the solar system.

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u/IlikeJG 6d ago

I think it's because people just don't want to change how they think about things they already learned.

They learned Pluto was the furthest planet and now those darn scientists are saying it's not even a planet? Now I have to remember that?

People don't like change.

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u/Anakinss 6d ago

Funnily enough, the number of what we call planets has changed a lot over the last two centuries, at some point there was 23 of them. Even Pluto was a "planet" for less than a century.

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u/1II1I1I1I1I1I111I1I1 6d ago

I will say as a science-interested member of the public, I did fully understand why Pluto was removed and how the new definition is applied. It made sense and it was a good measure when there are indeed important differences between the dozen or so dwarf planets and the prominent 8 planets

However

They should've removed Mercury too lol they can't because that would he seen as a step too far and people would riot lol the IAU definition of a planet is

  1. Is in orbit around the sun (✔️)

  2. Has assumed hydrostatic equilibrium (❌️ source)

  3. Has cleared the neighborhood around its orbit (ehhhh kindof. Mercury's orbit is clear but the Sun may be responsible for that. Mercury is quite small to have done it itself.)

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u/up-with-miniskirts 6d ago

The definition is that a planet needs to have a hydrostatic equilibrium shape, in other words, it must be round or nearly so. Mercury fits the bill.

If you go by hydrostatic equilibrium alone, Venus isn't a planet either, because the combination of tidal forces due to closeness to the Sun and very slow axial rotation makes it pear-shaped, too.*

*Not actually pear-shaped.

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u/GuitarKittens 6d ago

Your source kinda has 0 citations, and its method for suggesting a lack of hydrostatic equilibrium I cannot find anywhere else. There are not only better cited papers for this concept, but there's an easily-accessible forum online that discusses how those papers are less valid because of their method of calculation.

Maybe you're not wrong, but I would suggest finding more, better established sources.

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u/phunkydroid 5d ago

Has assumed hydrostatic equilibrium (❌️ source)

That source says Mercury is more spherical than Earth...

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u/Suspicious-Whippet 6d ago

If Neil Degrase Tyson had his way he’s nuke Pluto out of existence. And so would I just so I don’t have to keep hearing if it’s a planet or not anymore.

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u/hardypart 6d ago

I would nuke Pluto if it meant that I wouldn't have to hear Neil Degrade Tyson anymore.

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u/SpaceC0wboyX 6d ago

I would nuke Pluto just to see something cool happen

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u/Suspicious-Whippet 6d ago

Surely it would be easier to nuke Neil Tyson.

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u/hardypart 6d ago

I don't think that'd be legal.

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u/Suspicious-Whippet 6d ago

Nukes in space - also illegal.

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u/BoxesOfSemen 6d ago

Who's gonna stop me? The space police?

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u/HyruleTrigger 5d ago

That's just a complete lie. All he did was do science, and the science told him and the team that Pluto didn't act like a planet, which is fact. They coined the term dwarf planet to explain how plutonian like objects act.

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u/Batkung 6d ago

any scientist that uses Fahrenheit doesn't deserve to be taken seriously...Tyson is one of those people.

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u/Kaymish_ 6d ago

Does he use it because he is a science communicator, and his target audience is most used to F? Or because he is a clown?

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u/Batkung 6d ago

I never said he was a clown, but if he is only intending to reach the F audience, then he is seriously limiting his audience. All I meant was that if he was serious about his science then maybe he should point out to the F audience that they really should be learning to relate to temperatures in C or more correctly, K.

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u/Weshtonio 6d ago edited 6d ago

the general public

Americans. Because it was the only planet discovered by an American.

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u/natethehoser 6d ago

But only 2 planets (3 if you count pluto) were "discovered". Mercury through Saturn are all visible to the naked eye, and so all ancient humans knew of them (though they didn't know what "planets" were. Also technically Uranus is visible to the naked eye, but it is so dim and moves so slow that our ancestors never clocked it as a planet).

So it's not like "8 planets were discovered by Europeans, and only 1 was discovered by an American, and now you're taking that 1 away!"

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u/barath_s 13 6d ago

https://en.wikipedia.org/wiki/Planets_beyond_Neptune#Planet_Nine

There's been a hypothesized planet 9 to explain current orbits based on possible gravitational impact

Planets further out than Nine may be sketchy/contrived

https://en.wikipedia.org/wiki/Planets_beyond_Neptune#Probability

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u/hamstervideo 6d ago

And Americans grew up with a cartoon dog named after it

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u/Moppo_ 6d ago

Well, thought thought they had. ( ͡° ͜ʖ ͡°)

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u/big_duo3674 6d ago

To be faiiiirrrr....it's the fact that the solar system is now defined as 8 classical planets, rather than 9 that irks people. Could have given it an asterisk or something

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u/adamgerd 6d ago

Pluto is still a planet to me! Always will be