# Heat and Gravity

1. Jul 18, 2010

### calebhoilday

Can gravity absorb heat energy by converting it into gravitational potential energy?

I always imagine heat is just kinetic energy but more randomised. meaning that if such movement occurs against the force of gravity then, it is converted to gravitational potential energy.

2. Jul 18, 2010

### Staff: Mentor

Well, it depends on what exactly the constraints of your question are: a car converts chemical energy to heat energy to kinetic energy....which can then be converted to potential energy if you drive uphill.

3. Jul 18, 2010

### calebhoilday

well how about you have pressurised gas in a canister and you then release it into a long capped end pipe, that is vertical. If i released it in from the bottom, would it be cooler than if released from the top. Based on the idea that diffusion is powered by heat energy and when released from the bottom it works against gravity and from the top, gravity aids it.

Can heat turn directly into gravitational potential energy.

4. Jul 18, 2010

### Staff: Mentor

I suppose a gun firing up would probably also qualify: chemical energy -> heat energy -> kinetic and potential energy.

5. Jul 18, 2010

### calebhoilday

So, yes to the above?

6. Jul 19, 2010

### Andrew Mason

Conversion of kinetic energy of air molecules into gravitational potential energy is the main reason that the atmosphere does not leave the earth. The air molecules do not have sufficient kinetic energy at atmospheric temperatures to escape earth's gravity. It is also a factor causing temperature to decrease with increasing altitude.

AM

7. Jul 19, 2010

### calebhoilday

So, if these molecules that have converted heat energy to gravitational potential energy, condense then fall, gravitational potential energy is converted to kinetic energy?

8. Jul 19, 2010

### Andrew Mason

Correct.

AM

9. Jul 22, 2010

### calebhoilday

Can anyone link me to something that such a situation does not defy the second law of thermodynamics. It probably has to do with pressure and i would like have a better understanding.