Could gravity affect human evolution?

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Discussion Overview

The discussion explores the hypothetical effects of a future Earth-Moon system, where both bodies are tidally locked and face each other, on human evolution, particularly regarding height differences between populations on the lunar and anti-lunar sides of Earth. The scope includes speculative evolutionary biology and gravitational effects.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants propose that if the Earth and Moon became a true double planetary system, the gravitational effects of the Moon could influence human height, particularly suggesting that those on the lunar side might be taller due to stronger gravitational influence.
  • Others argue that the gravitational effect described would not be significant, comparing it to the current effects of the Moon, which do not result in noticeable changes in human height.
  • One participant notes that biological evolution involves inheritable traits and questions whether such gravitational changes would lead to evolutionary changes in humans at all.
  • Another participant emphasizes that the timeframe for such a scenario would be billions of years, not millions, and raises concerns about the Sun's lifecycle impacting this possibility.
  • There is a mention of tidal effects being weak and not contributing significantly to weight changes, suggesting that any height differences due to gravitational effects would be negligible.

Areas of Agreement / Disagreement

Participants express differing views on the potential impact of gravitational changes on human evolution, with no consensus reached on whether such effects would be significant or even relevant to evolutionary processes.

Contextual Notes

Limitations include assumptions about the future state of the Earth-Moon system, the definitions of a "true double planetary system," and the speculative nature of human evolution over such long timescales.

YoungDreamer
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I am wondering if millions of years from now if the Earth and Moon became a true double planetary system, where one side of each body continually face each other, if it could have affects on the height of humans. If people living on the "lunar side" would be taller on average than people on the opposite side of Earth because of the extra permanent affects of the Moons gravity?
 
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YoungDreamer said:
I am wondering if millions of years from now if the Earth and Moon became a true double planetary system, where one side of each body continually face each other, if it could have affects on the height of humans. If people living on the "lunar side" would be taller on average than people on the opposite side of Earth because of the extra permanent affects of the Moons gravity?

I'm not sure that locking the orbits would make the Earth-Moon system a "true double planetary system", but I could me mistaken about some definition involved.

That aside, I don't think you would get the gravitation affect you describe any more than we currently would with a full Moon directly overhead or directly beneath our feet. You are in free fall (and therefor weightless) with respect to the Moon.
 
If this were to happen it wouldn't be a product of evolution, biological evolution refers to inheritable traits with variation under environmental attrition. I'm not sure how to work it out but I suppose the lunar side would have slightly weaker gravity than the other side.

However how long away is this event? I doubt homo sapiens will be here in millions of years (some of our descendants might but that's another discussion)
 
YoungDreamer said:
I am wondering if millions of years from now if the Earth and Moon became a true double planetary system, where one side of each body continually face each other, if it could have affects on the height of humans. If people living on the "lunar side" would be taller on average than people on the opposite side of Earth because of the extra permanent affects of the Moons gravity?

A couple of points.
It would take billions, not millions of years for this to happen.
Our Sun will expand into a red giant before it can happen.
The Moon would have to be further away from the Earth when it happens, lessening its gravitational effect on the Earth from what its now.
The gravitational effect that we do feel on the Surface of the Earth is due to tidal effects, which actually pull outward on both the Lunar side and Anti-lunar side. (this is why we get two high tides a day.)
Even today, this tidal pull is very weak. The difference in the weight of your body with it and without it works out to something like 1/50th of an ounce. Maintaining a short haircut would have more effect on your on your weight. So, no, you would not expect to see any difference in height in people depending on where they live.
 

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