[skaper]

hi

ligth can travel like waves but also react like it has mass so it chages direction when a forse(like gravity) react at on it. thats y it does not travel on straigt line. but the curvature of spacetime. is an exlanation given by a. eistein to solve a problem which he fased in his theory.

[subversion]

how is it that a massless object like a photon can be effected by the curvature of space time?

[Guille]

Originally Posted by subversion how is it that a massless object like a photon can be effected by the curvature of space time?

that is something I have always wondered. You don't have to think about this thing in an Eistenian way but in clasical (newtonian) mechanics. Newton's geenral alw of gravitation is (GM-m)/d=F. sometimes the d (distance) is represented with r (radius). G is the gravitational constnat. Big M and small m are the masses of an object, so, with light it would be G times the mass of the earth (for example) minus the mass of light (=0) and all that devided by the distance between light and earth. so if you see you get a number of force. this is the force with which light is atracted by gravity to the earth.

[skaper]

hi

if you try to explain with the classic physics einsreins theory you will never find what is really going on. ligth has some special and strange peculiar- it none knowes y but we are able to watch them in experiments.

[Guille]

do you mean photons?

if not, what are you talking about?

Just for correction: I'm not explaining Eisntein's GR with clasical mechanics I'm explaning why light is atracted by the curvature of space-time i.e. gravity if i thas no mass, and this is explained by Newton's law of gravitation.

[skaper]

that's rigth. ligth has the ability to react like wave (radiation) but as well as particle (photon).but some particles (like electrons) react like ligth. so photons is an explanation for those special abilitys of light and on that we support our theories on ligth movement, which helped einstein on his own theory.

[centaurwind]

For my own understanding, light does not travel straight in the space but travels the shortest path possible in the space. As the result, if the space is curved, we can see the light travels in curvature.

[Guille]

Originally Posted by centaurwind For my own understanding, light does not travel straight in the space but travels the shortest path possible in the space. As the result, if the space is curved, we can see the light travels in curvature.

actually this can't be stated in such a convinced way. When we whach (even by inteligent experiments) light, it appears to be straight and go in straight lines. So, I would say this is relative. The shortest path possiblein the space (actually is in space-time) is called geodesic line (knowledge adquierd from AntonioLao's posts).