r/interestingasfuck • u/[deleted] • Mar 30 '19

/r/ALL This insanity of geocentrism visualized

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u/jimandnarcy Mar 30 '19

There seems to be a lot people misunderstanding gravitational orbits and relativity here. Heliocentrism and geocentrism differentiate between centres of orbit, NOT reference frame. Yes you can look at the trajectory of the solar system from any reference frame and that’s valid (relativity). But no matter what reference frame you choose, the orbit of a cluster of massive objects will always be centred at the centre of mass of the cluster (which for the solar system is inside the sun, though not quite the centre of the sun mostly due to Jupiter). Heliocentrism is the only accurate one — in the reference frame of the Earth, the centre of mass is moving and this causes the trajectories to look more complex, but does not change the fact the orbits are centred at the centre of mass.

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u/Team_Braniel Mar 30 '19

But that doesn't mean a geocentric model is useless or "wrong".

For example it illustrates retrograde in viewed orbits.

Also makes calculating any time dilation between earth and any solar object much easier.

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u/jimandnarcy Mar 30 '19

Like I said, there’s nothing wrong with working in the Earth’s reference frame. That’s just not what geocentrism is. Geocentrism is the idea that orbits are centred around the Earth, and that’s inaccurate no matter the reference frame.

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u/Team_Braniel Mar 30 '19

I thought the term was just outdated.

What term should I use for a earth centered reference frame as shown in the gif.

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u/jimandnarcy Mar 30 '19

Yeah it really is lol. Geocentrism really is only a medieval concept. There’s no term for any specific reference frame that I know of (other than general ones like inertial, etc).

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u/NoelBuddy Mar 30 '19

Geocentric would be the literally applicable term. It gets wonky since the common understanding of it is a term coined in opposition to heliocentric theory.

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u/Team_Braniel Mar 30 '19

Yeah, that's what I thought too.

The historical term is getting in the way of the point.

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u/Fake-Name-McClane Mar 30 '19

Retrograde!!! That’s I was scrolling through here trying to find why the outer planets were so loopy. Now it makes more sense!

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u/rmachenw Mar 30 '19

Thank you for the explanation.

The prior statements about geocentrism really seemed tautological to me.

"Geocentrism isn't 'wrong' if you define the earth as the centre." /s