Friday, November 23, 2018

general relativity - How exactly does gravity work?


The electromagnetic force and strong and weak forces require particles like photons and gluons. But in case of gravity there is no such particle found.


Every mass bearing object creates a gravitational field around it, and whenever another mass bearing object enters its field the gravitational force comes into operation.


If all other forces of nature have some particles associated with them why should gravity be an exception?


And if there is no such particle, what exactly is the gravitational field and how does it spread over an infinite distance and cause the gravitational force to operate?





Note: I am a high school student and have not studied quantum mechanics.



Answer



Since you don't fully understand the answer of JamalS, I'll try to explain it shorter and easier for you.



If all other forces of nature have some particles associated with them why should gravity be an exception?



No, it isn't an exception. Physicists believe that the particle for gravity (called graviton) does exist, it's just they haven't found it yet. Standard Model doesn't have gravity, but extended Standard Model may have. Thanks to string theory.



What exactly is the gravitational field and how does it spread over an infinite distance and cause the gravitational force to operate?




It is exactly the space and the time. How do space and time appear? Big Bang. How does gravity operate? A change of space and time give you a gravitation force. Like a change in position gives you velocity ($v=\Delta x$), a change in energy gives you work ($W=ΔKE$). A change is very important, it will give you another interesting entity. If you have studied differential, you now know how important it is: describing a change.


By referring a change of space and time, I don't mean like a car travels through cities from morning to afternoon. I mean the car reforms the shape of time and space itself.


From Wikipedia:



Matter changes the geometry of spacetime, this (curved) geometry being interpreted as gravity.



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