Register to reply

What is gravity?

by Nash Su
Tags: gravity
Share this thread:
Nash Su
#1
Apr5-12, 02:45 PM
P: 2
How does gravity work? I want to know where gravity comes from on the atom and how it attracts other matter towards it. Also the black hole gravity is so strong that not even light can escape it. Does this mean that light is being lightly bend when it passes another star/planet?
Phys.Org News Partner Physics news on Phys.org
Step lightly: All-optical transistor triggered by single photon promises advances in quantum applications
The unifying framework of symmetry reveals properties of a broad range of physical systems
What time is it in the universe?
phinds
#2
Apr5-12, 03:43 PM
PF Gold
phinds's Avatar
P: 6,338
Quote Quote by Nash Su View Post
Does this mean that light is being lightly bend when it passes another star/planet?
Yes.

Technically, light is bent by ANY object with mass, but of course unless the mass is large, the amount of bend is negligible.

I personally bend light all the time, but like many of my efforts, the effect is negligible.
Drakkith
#3
Apr5-12, 05:16 PM
Mentor
Drakkith's Avatar
P: 11,884
Quote Quote by Nash Su View Post
How does gravity work? I want to know where gravity comes from on the atom and how it attracts other matter towards it. Also the black hole gravity is so strong that not even light can escape it. Does this mean that light is being lightly bend when it passes another star/planet?
This is a very big subject. Currently our main theory of gravitation is General Relativity. GR says that mass and energy cause a curvature of spacetime which results in objects "attracting" each other. The reason why this results in an attraction is fairly technical and involves a lot of math you most likely have never seen or heard of before. I don't even know it very well myself, so I cannot explain it.

Anything with mass or energy will gravitate, so the force isn't being "emitted" by a specific spot on an atom, but by the whole atom. (Or, if you prefer, from each subatomic particle that composes the atom)

Interestingly, one of the first tests of Einsteins Genral Theory of Relativity was to measure the change in the path of light around the Sun during an eclipse.

haruspex
#4
Apr6-12, 01:15 AM
Homework
Sci Advisor
HW Helper
Thanks
P: 9,863
What is gravity?

Quote Quote by Drakkith View Post
Interestingly, one of the first tests of Einsteins Genral Theory of Relativity was to measure the change in the path of light around the Sun during an eclipse.
Just to clarify a possible misunderstanding for the reader: It's not that the eclipse changed the path of the light. It would have changed anyway, but the eclipse made it observable.


Register to reply

Related Discussions
Gravity: Point where Earth's Gravity and the Moon's cancel each other out? Advanced Physics Homework 21
How to calculate mass of fuel needed to escape Earth gravity vs. Mars gravity Astronomy & Astrophysics 2
Does gravity affect gravity the way gravity affects time? General Physics 12
[help]how to obtain gravity eqution from gravity field Action S? Special & General Relativity 3
[help]how to obtain gravity eqution from gravity field Action S? Advanced Physics Homework 2