# can gravity exist without mass?

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• 5 months ago

Yes. Light has gravity but no mass. The early stages of the universe didn't have mass but had gravity.

Theoretically, you could even form a black hole if you had enough light in a small enough area (it's called a kugelblitz). Although we have no idea how we or the universe would ever be able to create such a thing.

• nikki1234
Lv 7
5 months agoReport

yup, i had to look it up to check: https://www.wtamu.edu/~cbaird/sq/mobile/2014/04/01/light-has-no-mass-so-it-also-has-no-energy-according-to-einstein-but-how-can-sunlight-warm-the-earth-without-energy/

• oubaas
Lv 7
5 months ago
• 5 months ago

Yes. Energy has gravity. Even gravity itself produces gravity. A geon is a ball of only gravity.

Tension and stress and pressure also produce gravity.

• neb
Lv 7
5 months ago

Yes. Hasn’t anybody that answered this question heard of general relativity?

The source of gravity in general relativity is the stress-energy tensor (also known as the energy-momentum tensor). It has ten independent components. One is energy density (whether from mass or energy density from massless fields such as electromagnetic fields), three components are momentum density, six are pressure/stress.

There is a stress-energy tensor for electromagnetism.

There is a black hole solution called the Kerr metric that includes angular momentum as a source of gravity.

Even gravitational waves produce additional gravity because they carry energy-momentum

• nikki1234
Lv 7
5 months agoReport

• 5 months ago

I'm not a scientist or a physics expert but common Sense would dictate that in order to have some kind of force that hold you down you have to have some kind of mass to hold down.

• 5 months ago

Physics 101 says no, not possible.

• neb
Lv 7
5 months agoReport

This isn’t physics 101. This is general relativity

• Tom
Lv 7
5 months ago

No----Gravity is inherent in MASS. Gravity is a curvature in space--and felt when time (inherent 4th directional movement in mass interacts with it. the smallest mass/particle is ultimately a "Dimple" in space time.---So a lot of mass together makes a WARP in it.

Since Mass has in inherent Time component motion and is itself a bend in space--it all works together to make a kind of "INERTIA" resulting from rounding a space curve----Just as we feel in a moving car when we make a quick turn.-----We just do not perceive the 4D motion in our 3D perception so the inertia looks to us like a "Force" we call Gravity.

• 5 months ago

Yes... in a way.

The orbit of Mercury baffled astronomers for a while. Mercury orbits the Sun AS IF the Sun had more mass than it actually has (you can determine the mass of the Sun by the way the other planets orbit it).

In the mid 1910s, Einstein showed that, so close to the Sun, the energy density is so high that it increases the effect of gravity, even though this energy has no proper mass (it is mostly light).

Once the effect was identified (and validated), it was shown to act also on other planets (but to a much smaller extent as you moved away from the Sun).