What can we really learn about the effects of microgravity?

[dimreepr]

Since the ISS orbits at about 250 miles above the Earth so its actual gravity is 88.8 percent of that felt at ground level; what value can be derived from the experiments done on ISS in terms of actual microgravity?

 

As in how do we know that a plant that appears to grow well in simulated microgravity does so in a gravity that is much lower, like half way to Mars or well out of the solar system?

[Janus]

The net force felt by the plant in both cases is identical (other than insignificant differences in tidal forces). What other "affect" do you think gravity has?

[dimreepr]

What other "affect" do you think gravity has?

 

 

I don't know, hence my question, but thank you for your answer.

[swansont]

Since acceleration and gravity are indistinguishable, free fall and zero g should be as well

[dimreepr]

Since acceleration and gravity are indistinguishable, free fall and zero g should be as well

 

 

Why is that?

 

Gravity seems dependant on mass whilst acceleration seems dependant on energy.

[swansont]

 

 

Why is that?

 

Gravity seems dependant on mass whilst acceleration seems dependant on energy.

 

Acceleration is F/m. You have zero energy when you are stationary and begin the acceleration and lots of energy later on when you are moving quickly.

 

According to general relativity, acceleration and gravity are not distinguishable. If you were in a sealed room, you could not tell the difference between a 1g acceleration and being stationary on the earth's surface. IOW, acceleration is acceleration. Gravity is not special in that regard. But the only reason you feel the effects of gravity when standing on the earth is that you are being held stationary — you feel the earth pushing up on you. In free-fall, you feel nothing.