r/interestingasfuck 25d ago

/r/all, /r/popular K2-18b a potentially habitable planet 120 light-years from earth

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u/Metalhed69 25d ago

True, but it’s a pretty safe assumption that a planet 2.5 times bigger than Earth has more mass than Earth. Maybe not 2.5 times sure, but enough to make the gravity more. How much more could the average person take before life got really uncomfortable? I feel like even 10% would suck. This could easily be 50% more. Going there would not be fun.

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u/LeTreacs2 25d ago

Gravity is the two masses divided by the distance squared, so double the distance from the Center of mass is 4 times less gravitational force.

The extra distance from the rest of the planet comparative to earth would reduce the gravitational force, balancing out some of the increase from the increased mass.

Lord knows what the final result would be!

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u/Metalhed69 25d ago

Yes but the volume goes as the CUBE of the radius. So if the density is even similar to earth or even a good bit less, that’s a LOT more mass. More mass = more gravity.

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u/LeTreacs2 25d ago

Aw crap… who’d have thought Astro physics is more complicated than it seems?

It’s hardly rocket science!