Waxy asked in Science & MathematicsPhysics · 1 month ago

# Where does the energy for gravity come from?

Actually, gravity is just the warping of space and time, so where does the energy for the upward acceleration of Earth come from.  For instance, if you were on a spacecraft accelerating at 9.8 m/s^2, you would feel the same force on your body as if you were on Earth and the situations would be corollary.  However, the spacecraft would need to provide energy for that acceleration, even if you were completely stationary on the spacecraft, and would need fuel to for that energy/acceleration.  So, where does Earth get its energy/fuel to provide for the acceleration that we feel while sitting, laying down or doing anything else?

Update:

To Awesome Bill, this video @ 10:27 describes spacetime as constantly falling inward and the surface of the earth as constantly accelerating upward against it:

Regardless, gravity and acceleration are equivalent so if it takes energy to accelerate something, gravity should be using energy.  If that energy is drawn from matter itself, I would expect matter to be consumed as it is converted to energy.  This does not seem to be the case however.

Relevance
• Jim
Lv 7
1 month ago

Energy = 0

While Earth is accelerating to sun, the sun is accelerating to Earth. Net sum 0 energy.

• Tom
Lv 7
1 month ago

It comes from TIME---which is a Constant MOTION, at a factor of light speed, inherent in all matter. In the direction of the 4th dimension-----Like the background motion in the enclosed back of a truck traveling 60 mph on a smooth road.  You are unaware of any motion, things around you appear to stay in the same place too---Because EVERYTHING is moving in the same speed and direction on the highway.

Should the highway curve---- you would THEN feel a Force PULLING YOU to the side.

So large masses WARP SPACE (the time highway)in the direction of the 4 Dimension (we cant feel or conceive of)  as we are carried along in the time motion, and hit this curve and get sucked along with it, we FEEL a FORCE seeming to pull us toward the MASS---we call GRAVITY.

• 1 month ago

"Where does the energy for gravity come from?"

If you can answer that question, the Nobel prize would be instantaneous!

Warping of spacetime is just one of a few mathematical ways to model the effect of gravity. It supposes that there exists such a "thing" as spacetime, and that its warping has an effect on anything. It is, so far, a mathematical ploy.

The accelerating spacecraft analogy is often used to say that a constant acceleration could not be distinguished from a constant gravity field on a planet. And yet, there would be a difference.  In the spacecraft, all the "lines of gravity field" (another mathematical ploy) would be parallel. On a planet, they are not (they converge towards the centre).

Your question (where does the energy come from) is exactly the kind of thing that led Albert Einstein (and others, even before him) to conclude that gravity is NOT a force, even though it feels like one.

• Rita
Lv 6
1 month ago

Gravity just provides a way to temporarily store energy in an object. We call the energy that an object gains when you lift it against a force "potential energy". The energy comes from the lifting agent and not from the force.

• 1 month ago

They don't know.  All the math has been worked out.  No gravitron found yet.  Gravity in NOT just the warping of space and time.  There is no such thing as space and there is no such thing as time.  It's spacetime.  One word for one thing.  Spacetime is the universe.  Spacetime is created by the gravity of mass.  Spacetime AKA the universe is created as mass moves outward.  Your comparison does not fit for many reasons.

• 1 month ago

The part about upward acceleration has me confused. Are you talking about the upward acceleration of an object leaving the surface of Earth, or the angular momentum of Earth along its orbit around the Sun?

The expansion of the Universe wouldn't allow any object to sit perfectly still. But for the sake of demonstration lets suppose it could allow the Earth to sit motionless.

Due to it's mass density, gravity would result in the warpage of spacetime in much the same way as it is while in orbit around the Sun.

So again, I don't understand what you're trying to imply by the upward acceleration of Earth.

• ?
Lv 7
1 month ago

As I understand it, all energy is ultimately traceable back to the start of the universe and an instant of extremely low entropy, ie all energy of the universe in the same one place. The expansion of space and generally homogeneous distribution of energy is then apparently a valid outcome according to Einstein's field equations with the "local" variations in energy density presumably being due to tiny scale quantum randomness that was suddenly hugely expanded such that it became  much larger scale features. Everything we see happening now - planets and stars forming, suns shining, trees growing etc. is ultimately part of a complex process of all that energy slowly increasing in entropy (flattening out all variations in energy distribution) according to countless paths of least action until it becomes actually homogeneous - the heat death of the universe.

• 1 month ago

If I want to provide a sort of philosophical answer, I could say that mass and energy are equivalent, and that MASS is the source of gravity.  (F = GmM/r^2.)

If I want to provide a more technical answer, I could say that we do not feel "acceleration" while sitting, etc.  We feel a force, which is related to the product of our mass and the earth's mass.  The only ACCELERATION that we experience while sitting is our centripetal acceleration due to the spinning of the earth, but this is a tiny and trivial effect compared to the gravitational acceleration that we experience when we fall down.  Keep in mind that acceleration is a change in velocity.

• Anonymous
1 month ago

enigma - nobody knows

• 1 month ago

We can describe how gravity acts but we still can't describe exactly how it works.

A nice way to think about it is "matter tells space how to curve, and space tells matter how to move."  That's an eloquent way of describing it but we still don't actually know precisely how it works.