I In Freefall orbiting Jupiter versus Earth

[Albertgauss]

TL;DR Summary

Jupiter g ~ 25 Would you feel it?

I know that in Earth, an astronaut feels weightless in orbit but actually is not. The astronaut would not feel his own weight until he actually stands on a floor where his feet point towards the Earth as the Normal Force is the perception of weight.

So, in Jupiter, where g ~ 25, an astronaut in freefall also would not feel their own weight. However, does that mean there would be no biological effects despite the increased gravity?

I have heard it said that a person who normally has a weight of 600 Newtons on Earth would then weigh ~ 1500 Newtons on Jupiter, enough to have a heart attack since a normal heart could not pump blood through such excess weight. But if the person is in freefall in Jupiter, this would not happen as they would need to have their feet on the surface of a ship to feel this 1500 Newton. Is this correct?

Please ignore everything else about Jupiter except for what is the discussion here. I am well aware of all the problems of falling into Jupiter, just had a question of this one detail.

 

[PeroK]

Let's stick to the classical theory of gravity. There is a significant gravitational force acting when you are in freefall. But, because the force is the same on each particle, there is no additional internal stress or strain that would enable you to measure the overall gravitational force. For that reason, you would feel nothing, whether it's Jupiter or the Earth.

The only time you would feel anything is if the differential in gravitational force between, say, your head and feet was large. This will be negligible for a planet even the size of Jupiter. This is called tidal gravity, and it's this difference in the Moon's gravity between one part of an ocean and another that causes the tides. If, say, the Earth was falling towards Jupiter, then this tidal gravity between the part of the Earth that was closest to Jupiter and the part that was furthest away would be significant and the Earth would be stretched as a result.

 

[Albertgauss]

Sounds good. I see where I was getting confused. Consider this answered.