Where does the loss of gravitational potential energy goes?

In summary: The potential energy gets smaller in magnitude but larger in value. However, at infinite separation, the potential energy is still zero. The star's changing mass results in essentially no change in potential energy for a planet and a star separated by a very, very large distance.The potential energy gets smaller in magnitude but larger in value. However, at infinite separation, the potential energy is still zero. The star's changing mass results in essentially no change in potential energy for a planet and a star separated by a very, very large distance.Thanks for your reply!
  • #1
J. Richter
9
0
Hi.

Imagine a closed physical system (a universe) with only one star like our Sun, and one planet like our Earth, but so far away from each other, that the gravity from both matters only has a very small effect on each other.

There is a (almost maximum) gravitational potential energy between the star and the planet, even that they are far away from each other.

The star converts mass into energy as time goes by, and the gravitational potential energy between the star and the planet gets smaller because of that.

This loss of potential energy doesn’t seem to be included in the physical processes around the star, because how is the star to know the mass of the planet so far away, and the amount of the potential energy?

My question is:

Where does the loss of gravitational potential energy between the star and the planet goes?

Regards from J. Richter
 
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  • #2
J. Richter said:
There is a (almost maximum) gravitational potential energy between the star and the planet, even that they are far away from each other.
The potential is negative definite, with a maximum of zero at infinite acceleration.

The star converts mass into energy as time goes by, and the gravitational potential energy between the star and the planet gets smaller because of that.
The potential energy gets smaller in magnitude but larger in value. However, at infinite separation, the potential energy is still zero. The star's changing mass results in essentially no change in potential energy for a planet and a star separated by a very, very large distance.

This loss of potential energy doesn’t seem to be included in the physical processes around the star, because how is the star to know the mass of the planet so far away, and the amount of the potential energy?
How does the star "know" the mass of a planet that is fairly close to the star? How is a separation of 1AU any different than a separation of billions of AUs?
 
  • #3
D H said:
The potential is negative definite, with a maximum of zero at infinite acceleration.
The potential energy gets smaller in magnitude but larger in value. However, at infinite separation, the potential energy is still zero. The star's changing mass results in essentially no change in potential energy for a planet and a star separated by a very, very large distance.
Thanks for your reply!

Since the star and the planet has a very small effect on each other after all, during very long time, they would be drawn towards each other because of gravity, stronger and stronger, resulting in a big collision, that would result in more heat in that universe.
But for now, this has not happened yet therefore there must be a positive (not yet released) energy between the star and the planet.

The star loses energy, and the eventual collision in the future between the star and the planet would result in a smaller and smaller crash.

Where does this potential energy go?
D H said:
How does the star "know" the mass of a planet that is fairly close to the star? How is a separation of 1AU any different than a separation of billions of AUs?
Your right, that was a clumsy way of trying to say what I meant:
It’s hard to imagine that this “lost” potential energy mentioned above, is converted into another kind of energy together with the converted mass from the sun.
 
  • #4
the star is constantly radiating energy in the form of light and cosmic radiation, which should make up for any 'lost' gravitational potential.
 

Related to Where does the loss of gravitational potential energy goes?

1. Where does the loss of gravitational potential energy go?

When an object falls from a higher altitude to a lower altitude, it loses gravitational potential energy. This energy is transformed into kinetic energy, which is the energy of motion. The object gains speed as it falls, and this increase in kinetic energy is equal to the decrease in gravitational potential energy.

2. Does the loss of gravitational potential energy only occur when an object falls?

No, the loss of gravitational potential energy can occur in various situations. For example, when a pendulum swings, it loses gravitational potential energy at the highest point and gains it back at the lowest point. Similarly, when an object is thrown upwards, it loses gravitational potential energy as it rises and gains it back as it falls.

3. What determines the amount of gravitational potential energy an object has?

The amount of gravitational potential energy an object has depends on its mass, the acceleration due to gravity, and its height above the ground. The higher the object is and the more massive it is, the more gravitational potential energy it has.

4. Can gravitational potential energy be converted into other forms of energy?

Yes, gravitational potential energy can be converted into other forms of energy. As mentioned earlier, it can be transformed into kinetic energy when an object falls. It can also be converted into thermal energy when an object hits the ground, creating heat. Additionally, it can be converted into electrical energy through hydroelectric power plants, where the potential energy of water at a higher altitude is used to generate electricity.

5. Is the loss of gravitational potential energy always a bad thing?

No, the loss of gravitational potential energy can have beneficial effects. For example, it can be used to generate electricity as mentioned in the previous answer. It can also be used to propel objects, such as water in a dam or a roller coaster car. It is only considered a negative thing when it results in an unwanted decrease in an object's potential energy, such as when an object falls and breaks.

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