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QuantumKing
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I was wondering, how does light bend in very intense gravitational fields, if it has no weight? And does anyone have a good source for facts on spacetime curvature, gravity and such? Thanks
Gravitational attraction attracts everything including things that don't have mass. It is a common misunderstanding that something needs to have mass to become attracted to a gravitational field.QuantumKing said:I was wondering, how does light bend in very intense gravitational fields, if it has no weight? And does anyone have a good source for facts on spacetime curvature, gravity and such? Thanks
QuantumKing said:I was wondering, how does light bend in very intense gravitational fields, if it has no weight? And does anyone have a good source for facts on spacetime curvature, gravity and such? Thanks
notknowing said:Of course, light DOES have mass since the energy of a photon is Planck's constant times its frequency. Hence, the mass is given by this energy divided by c**2. Only the photon's rest-mass is zero but since the photon is not at rest, one should not concentrate on this.
No. Light is energy.Euclid said:If I'm not mistaken, light has energy by virtue of its motion, E = pc = h nu. The equation E = m c^2 only holds for bodies at rest.
Don't you mean that in calculating the acceleration due to gravity, the mass cancels out? It does not cancel out in calculating the gravitational force.DaveC426913 said:"Gravitational attraction attracts everything including things that don't have mass."
In fact, when you calculate the pull that a massive body has on a small body, the mass of the small body cancels out of the equation, meaning that it doesn't matter how small the body is in how it is being affected (which is how the space station and a stray bolt can follow the same orbit.)
It also means the smaller body could have a mass of zero.
neophysique said:E = pc but p is also defined as mv. So why don't photons in this
Energy equation have a mass of m?
Euclid said:If I'm not mistaken, light has energy by virtue of its motion, E = pc = h nu. The equation E = m c^2 only holds for bodies at rest.
notknowing said:No, it holds always !
selfAdjoint said:No it doesn't. Study up.
QuantumKing said:I was wondering, how does light bend in very intense gravitational fields, if it has no weight? And does anyone have a good source for facts on spacetime curvature, gravity and such? Thanks
pess5 said:Mass warps the fabric of space, which results in curved spacetime, otherwise known as gravity wells or dents in space and time. The light follows a curved path thru the warped spacetime, which is the energy free path. Matter follows curved paths as well, which is why we remain in orbit about the sun. Per Einstein, gravitation is not really a force in the traditional sense. Instead, the dents in a non euclidean spacetime direct a body's motion, whereby curved paths become the inertial paths.
Light does not have rest mass, but it does have an effective mass and carries momentum.
Here's a link about the mass of light, and which suggests that light produces gravitation ...
http://math.ucr.edu/home/baez/physics/Relativity/SR/light_mass.html"
There are many links which discuss the bending of light. I'm having a little trouble finding a good one though.
First off gravity bends light in all fields whether strong or weak. If the field is weak its just that much harder to detect. Second, Gravity is that field which attracts objects which have mass. Since Einstein showed that since light had energy it has mass. If you pick up a copy of the Feynman Lectures you'll read this - From the Feynman Lectures Vol -I page 7-11, Section entitled Gravitation and RelativityQuantumKing said:I was wondering, how does light bend in very intense gravitational fields, if it has no weight? And does anyone have a good source for facts on spacetime curvature, gravity and such? Thanks
One feature of this new law is quite easy to understand is this: In Einstein relativity theory, anything which has energy has mass -- mass in the sense that it is attracted gravitationaly. Even light, which has energy, has a "mass". When a light beam, which has energy in it, comes past the sun there is attraction on it by the sun.
notknowing said:Hi, I took a look at the link you mentioned. I do not agree however with their opinion on "modern" and "outdated" definition of mass. For me, this is not just a matter of convention. For a moving particle, it is the relativistic mass which is determining the gravitational field its producing not the so-called rest-mass. For a photon, it is also its relativistic mass (nonzero) which will generate a gravitational field and not its rest-mass (which is zero). Or will those with the "modern" view of mass assert that light can not produce a gravitational field (however weak) ?
Gravity can cause light to bend as it travels through spacetime. This is because gravity warps the fabric of spacetime, creating a curved path for light to follow.
No, once light enters the event horizon of a black hole, it cannot escape. This is because the intense gravity within a black hole bends spacetime to such an extreme degree that even light cannot escape its grasp.
Yes, gravity can affect the speed of light. According to Einstein's theory of general relativity, gravity can slow down time and thus, the speed of light. This is because gravity warps spacetime, causing light to travel a longer distance in the same amount of time.
The curvature of spacetime caused by gravity can affect the perception of time. This is known as time dilation, where time passes slower in areas with stronger gravitational forces. This means that time can pass at different rates for observers in different gravitational fields.
Yes, gravity can affect the color of light. This is due to the phenomenon known as gravitational redshift, where light waves are stretched as they travel through a strong gravitational field, causing them to appear redder to an observer. This effect has been observed in the light from stars near massive objects like black holes.