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Yeuph t1_j3wlhwh wrote

Reply to comment by johnfogogin in Astronomers find 2nd Earth-size planet in intriguing alien solar system by Gari_305

I wonder what the "gravity" difference is when you're standing outside of the orbit vs when you're inside the orbit being pushed outward while standing on the planet. It's probably small but measurable.

I think the centrifugal force causes a weight difference of about 0.5% on the Earth standing on the equator vs standing on the poles, it's pretty large actually

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Schyte96 t1_j3wuus6 wrote

  1. That is due to the centrifugal force due to the rotation of the Earth, and not the orbit of the Earth around the Sun.

  2. Only 1/3rd of that 0.5% is due to the centrifugal force, the rest is due to the oblateness putting you about 21km further from the center of the earth when on the equator vs the poles.

I think both of these effects would be smaller, as the planet is likely tidally locked, making it's rotation slower than Earth, which also makes the equatorial bulge smaller.

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Yeuph t1_j3wyfcl wrote

Yes I know it is due to the centrifugal force, which was why I said that.

The question about the planet was not about that, it was about the effect of a fast orbit on perceived gravity depending upon which side of the planet you were on relative to the orbit

The earth thing was just to show these types of effects can have measurable effects, not that it was exactly the same

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ChalupaCabre t1_j3wu251 wrote

Do you mean you wonder what the gravitational force is on that planet, compared to earth’s whopping 9.807 m/s²?

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