# How does gravity work? **URL:** \ **Category:** Factual Questions\ **Created:** [June 18, 2003, 7:39am UTC](https://boards.straightdope.com/t/how-does-gravity-work/182658 "2003-06-18T07:39:26Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![Major\_Kong](https://avatars.discourse-cdn.com/v4/letter/m/b9bd4f/32.png) [@Major\_Kong](https://boards.straightdope.com/u/Major_Kong)\ **Post date:** [June 18, 2003, 7:39am UTC](https://boards.straightdope.com/t/how-does-gravity-work/182658/1 "2003-06-18T07:39:26Z")
I know gravity is equal to the mass of one object times the mass of a second object divided by distance squared. But what causes the attraction? ---
**Author:** ![eburacum45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eburacum45/32/8690_2.png) [@eburacum45](https://boards.straightdope.com/u/eburacum45)\ **Post date:** [June 18, 2003, 8:16am UTC](https://boards.straightdope.com/t/how-does-gravity-work/182658/2 "2003-06-18T08:16:28Z")
Well, it is the mass that causes the attraction, but this opens up lots of other questions. What causes the mass to exist and to have gravity? How is the gravity propagated or transmitted across space? Newton didn’t know, he just called it action at a distance. Eienstein didn’t know, but he said mass distorted space-time to create gravity ‘wells’ which caused massive objects to be experience a force towards each other. Nowadays some people put the propagation of gravity down to particles called gravitons, although there are problems with this theory; not all quantum gravity theories require gravitons, but put the effect down to variations in the vacuum foam itself. * * * SF worldbuilding at [http://www.orionsarm.com/main.html](http://www.orionsarm.com/main.html) ---
**Author:** ![Aro](https://avatars.discourse-cdn.com/v4/letter/a/b3f665/32.png) [@Aro](https://boards.straightdope.com/u/Aro)\ **Post date:** [June 18, 2003, 8:26am UTC](https://boards.straightdope.com/t/how-does-gravity-work/182658/3 "2003-06-18T08:26:34Z")
[What causes Gravity?](http://math.ucr.edu/home/baez/physics/Relativity/GR/gravity.html) Think of space as a flat rubber sheet and the planets as balls of metal sitting on that surface. The larger the ball the greater the indentation in the sheet. This can cause the smaller balls to fall into hollows caused by the larger object, creating a ‘virtual’ attraction towards that larger object. I’m sure a real physicist will be along soon to expalin this much better than I can. ---
**Author:** ![MC\_Master\_of\_Ceremonies](https://avatars.discourse-cdn.com/v4/letter/m/bb73d2/32.png) [@MC\_Master\_of\_Ceremonies](https://boards.straightdope.com/u/MC_Master_of_Ceremonies)\ **Post date:** [June 18, 2003, 9:44am UTC](https://boards.straightdope.com/t/how-does-gravity-work/182658/4 "2003-06-18T09:44:17Z")
In General Relativity gravity warps spacetime, which means the topography of space around a massive object is altered so that other objects fall towards it. Each object has gravitational potential energy which is at zero when it is outside of any gravitational field (which is impossible as gravitational fields only go to zero at infinite distances), this is a convention but it does have some correlation with reality as it is believed that GPE corresponds to the rest energy of an object. As an object moves towards another object it loses GPE as the GPE is converted to the kinetic energy of the attraction. As mentioned above soem physicists have been searching for the elusive graviton, a particle which when exchanged communicates a gravitational effect. ---
**Author:** ![CurtC](https://avatars.discourse-cdn.com/v4/letter/c/ce73a5/32.png) [@CurtC](https://boards.straightdope.com/u/CurtC)\ **Post date:** [June 18, 2003, 2:21pm UTC](https://boards.straightdope.com/t/how-does-gravity-work/182658/5 "2003-06-18T14:21:43Z")
In other words, if you figure out “what causes gravity,” you can go ahead and book your flight to Sweden. ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [June 18, 2003, 2:31pm UTC](https://boards.straightdope.com/t/how-does-gravity-work/182658/6 "2003-06-18T14:31:26Z")
> [@](#): > > \*Originally posted by Major Kong \* > \*\*I know gravity is equal to the mass of one object times the mass of a second object divided by distance squared. But what causes the attraction? \*\* [nitpick] The _force_ of gravity, F = (G x m x m’) / r[sup]2[/sup]. G is the universal gravitational constant–bassically a conversion factor from mass to gravitational force, and is equal to 6.672 x 10[sup]-11[/sup]. you can find the acceleration due to gravity at the surface of a given body by substituting 1 for one of the mass values and entering the body’s radius for r. [/nitpick] ---
**Author:** ![zoid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/zoid/32/336_2.png) [@zoid](https://boards.straightdope.com/u/zoid)\ **Post date:** [June 18, 2003, 4:19pm UTC](https://boards.straightdope.com/t/how-does-gravity-work/182658/7 "2003-06-18T16:19:53Z")
[slight hijack] I thought I read an article on the Scientific American web site not too long ago that claimed that gravitational force did not act instantaneously and the lag could actually be measured when the objects were sufficiently far apart. The point was that this had significant implications in the “gravity is mass warping space/time” theory. Anyone else remember this? [/slight hijack] ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [June 18, 2003, 4:27pm UTC](https://boards.straightdope.com/t/how-does-gravity-work/182658/8 "2003-06-18T16:27:46Z")
> [@](#): > > \*Originally posted by zoid \* > \*\*[slight hijack] > I thought I read an article on the Scientific American web site not too long ago that claimed that gravitational force did not act instantaneously and the lag could actually be measured when the objects were sufficiently far apart. The point was that this had significant implications in the “gravity is mass warping space/time” theory. > > Anyone else remember this? > [/slight hijack] \*\* That’s a central tenet of general relativity. The speed of gravity is, in fact, exactly equal to _c_. ---
**Author:** ![t-keela](https://avatars.discourse-cdn.com/v4/letter/t/a3d4f5/32.png) [@t-keela](https://boards.straightdope.com/u/t-keela)\ **Post date:** [June 18, 2003, 4:45pm UTC](https://boards.straightdope.com/t/how-does-gravity-work/182658/9 "2003-06-18T16:45:40Z")
Not a simple answer to this one (think string theory). I find this site has pretty good info. attempts at lay explanations and w/ sources as well. As was said before, answer this question and you can write your own ticket. > **[How does gravity work?](https://science.howstuffworks.com/environmental/earth/geophysics/question232.htm)** > > Gravity is a force that we experience every minute of our lives, but hardly notice or give a passing thought to in our daily routines. Have you ever wondered what gravity is and how it works? Learn about the force of gravity in this article.