this post was submitted on 24 Feb 2024
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xkcd

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https://xkcd.com/2898

Alt text:

"Some people say light is waves, and some say it's particles, so I bet light is some in-between thing that's both wave and particle depending on how you look at it. Am I right?" "YES, BUT YOU SHOULDN'T BE!"

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[–] [email protected] 131 points 8 months ago (5 children)

And that point is inside the sun.

[–] [email protected] 69 points 8 months ago (5 children)

No actually. Due to Jupiter, the centre of mass of the solar system is actually very slightly outside of the sun

[–] [email protected] 47 points 8 months ago (1 children)

Leave it to Jupiter to mess yet another thing up

[–] [email protected] 18 points 8 months ago

Stupid lazy ass diabetus planet doesn't even have enough mass to fuse its hydrogen.

[–] [email protected] 19 points 8 months ago (2 children)

Wouldn’t the center of mass constantly be shifting by the planets’ varying positions in orbit?

[–] [email protected] 26 points 8 months ago* (last edited 8 months ago) (1 children)

Yes, but it's mostly shifting because of Jupiter. It's just so dang heavy. Like, a couple times heavier than every other planet put together. I don't have the brain wattage to do the cool math right now, but a quick google search says that while the barycenter of the solar system does depend on all the planets, more often than not, it is outside the sun

[–] [email protected] 15 points 8 months ago* (last edited 8 months ago)

Easy reminder:

sun ~ 10^30 kg
jupiter ~ 10^27 kg
earth ~ 10^24 kg

so the ratio is always 1000:1

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[–] [email protected] 11 points 8 months ago

So doesn't that mean the earth and sun do not orbit a common center but a varying point based on mostly Jupiter?

Centrists have bamboozled me again!

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[–] [email protected] 31 points 8 months ago* (last edited 8 months ago) (2 children)

No the comic is pointing out that the sun and the earth are both orbiting the milky way galactic center.

Edit: While also true, I was wrong, they orbit the center of mass of the two body problem (earth and sun). I still think that's too simple of a way to look at it. It's not a two body problem and the other planets and the whole galaxy are also in play.

[–] [email protected] 19 points 8 months ago (3 children)

I mean technically every body in the entire universe exerts gravity on everything else as long as it's in your light cone

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[–] [email protected] 106 points 8 months ago (1 children)
[–] [email protected] 52 points 8 months ago* (last edited 8 months ago) (1 children)

I appreciate the origin story being included in this cliché, cuz it got repeated so often on Reddit that people seemed to forget it was said by a parody of an obnoxious heartless bureaucrat and repeat the phrase without irony.

[–] [email protected] 13 points 8 months ago (1 children)

You know, you are technically correct.

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[–] [email protected] 78 points 8 months ago* (last edited 8 months ago) (5 children)

It's called a barycenter, kids, a common center that both objects circle around. That common center happens to be inside the sun, but that's a topic for next week's class in this semester's AP Astrophysics program.

[–] [email protected] 22 points 8 months ago (1 children)

Same for earth and moon. The center is inside earth. But not that close to the center of the earth itself

[–] [email protected] 19 points 8 months ago (1 children)

Meanwhile, Pluto and Charon noticeably orbit each other, the barycenter being fully outside of Pluto's surface.

[–] [email protected] 13 points 8 months ago

And Jupiter is so massive that its barycentre is (barely!) outside of the sun!

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[–] [email protected] 54 points 8 months ago* (last edited 8 months ago) (2 children)

Apply that to the flat earth debate and you get an oblate spheroid.

[–] [email protected] 10 points 8 months ago

You're an oblate spheroid

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[–] [email protected] 40 points 8 months ago (7 children)

Sometimes, both can be wrong. Both orbit the moon

[–] [email protected] 19 points 8 months ago (1 children)

The Earth–Moon–Sun three body problem is apparently something that has been studied quite a bit in physics.

[–] [email protected] 10 points 8 months ago (2 children)

And of cause there are 3 camps and alot of disagreements but essentially, the majority of scientists argue, like me, that it is the moon which is the center. You can always cite some fringe scientists arguing otherwise, that doesn't change the general consensus.

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[–] [email protected] 35 points 8 months ago (2 children)

Is this... an introductory course in relativity, disguised as a joke?

Am I accidentally learning something here?

Guys?

[–] [email protected] 20 points 8 months ago (1 children)
[–] [email protected] 36 points 8 months ago* (last edited 8 months ago) (3 children)

Not really, relativity plays no role here. It's classical Newtonian physics.

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[–] [email protected] 27 points 8 months ago (29 children)

As a middle ground kind of guy, I would like to pre-emptively state that a lot of us don't actually think the answer is always the middle ground between two stances. It's just that we're more likely to propose a middle ground solution because we evaluate the plausibility of both stances in a more balanced way (as opposed to existing-stance-holders who are prone to bias towards their own stance.) When the two seem roughly equal in plausibility (which happens fairly often, otherwise the argument would be more one-sided,) that's an indication to evaluate the middle ground as well.

Middle ground folks are often caricaturized as wanting to find the middle ground between an objectively sensible point A and a radically wrong point B, when the spectrum of opinions is sort of like [ - - - - - A - | - - - - - - B ]. In that caricature, we're looking for a middle ground at point C [ - - - - - A - | - - C - - - B ], when in actuality we're evaluating (and not automatically accepting) something two or three steps closer to A. In some such cases, A might already be the most sensible middle ground.

[–] [email protected] 22 points 8 months ago (7 children)

Technically, the sun is pulled by the earth too so it’s sort of true.

[–] [email protected] 125 points 8 months ago (14 children)

I mean, yeah. That's the joke.

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[–] [email protected] 19 points 8 months ago (3 children)

Except it's still inside the sun, so depending on how big you view the center of the sun it could still be wrong.

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[–] [email protected] 13 points 8 months ago (4 children)

My thought exactly but isn't the common center still inside the sun?

[–] [email protected] 15 points 8 months ago (1 children)

Yes, but they still both orbit the black hole in the center of our galaxy

[–] [email protected] 11 points 8 months ago (3 children)

The urge to orbit a black hole is universal

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[–] [email protected] 18 points 8 months ago

The alt text makes this xkcd tier

[–] [email protected] 18 points 8 months ago* (last edited 8 months ago) (5 children)

I mean, no, not really. The gravitational center of the sun-earth system is within the sun itself, so the earth definitely orbits the sun and the sun definitely does not orbit the earth. Let alone the fact that the sun’s movement is predominantly driven by Jupiter. (The gravitational center of the sun-Jupiter system is just above the sun’s surface.)

[–] [email protected] 11 points 8 months ago (4 children)

Pretty sure you can chose earth as fix point and have everything rotate around it on really strange orbits. Everything is kind of relative.

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[–] [email protected] 17 points 8 months ago
[–] [email protected] 10 points 8 months ago (1 children)

If this topic proves anything, it's that we should make sure everyone is assuming the same thing before discussing, or clarify before discussing.

You can literally come up with different answers without further clarification.

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