Can someone help me with this contradiction?
Light travels at 186,000mps, because it has no mass E=mc² does not apply. Therefore like(photons) can travel at that speed.
Gravity's equation is this: Gravitational force = (G * m1 * m2) / (d2)
m1 and m2 are the masses of the objects.
So gravity attracts mass. Then how does a black hole have a gravitational force great enough to pull something which has no mass?
You have to ask why gravity attracts light...
Energy and mass both produce spacetime curvature... Mass warps spacetime moreso than energy note. Thus, around a massive body like a Sun, light can couple to gravity, because gravity is the same as spacetime curvature.
Energy and mass both produce spacetime curvature... Mass warps spacetime moreso than energy note. Thus, around a massive body like a Sun, light can couple to gravity, because gravity is the same as spacetime curvature.
You have to bring in quantum theory. According to the equivalence principle light has and inertial mass that is equal to planks constant * the lights frequency divided by the speed of light squared. Thus light can be affected by gravitational fields.
Black holes come out of Einstein's General Theory of Relativity. If understand what I have been reading lately, General Relativity even allows speeds greater than c (speed of light). The presence of gravitational fields overrules Special Relativities rule that v must always be less than c. The math of General Relative is a bit more than I can handle but it is a fascinating read (though I have to drink lots of coffee to keep alert).
Black holes come out of Einstein's General Theory of Relativity. If understand what I have been reading lately, General Relativity even allows speeds greater than c (speed of light). The presence of gravitational fields overrules Special Relativities rule that v must always be less than c. The math of General Relative is a bit more than I can handle but it is a fascinating read (though I have to drink lots of coffee to keep alert).
Im not sure where I read it but some scientists made light travel faster than....light through some gas or something, anyone else know about this?
Light was made to move at superluminal speeds by two German scientists. They acheived this by sending the photon down a set of carefully placed prisms. Following their paths, they noticed that one of the photon performed a task that was much faster than any other other particles. They solved the problem by saying the photon actually quantum tunneled to its new position.
Good call, Neo. The best way I've heard it put is "matter warps space-time, and space-time tells matter (and light) how to act".
QUOTE (am_Unition+Sep 9 2007, 06:58 AM)
Good call, Neo. The best way I've heard it put is "matter warps space-time, and space-time tells matter (and light) how to act".
Massenergy curves space and slows time.
Massenergy curves space and slows time.
QUOTE (guest1+Sep 9 2007, 02:27 AM)
You have to bring in quantum theory. According to the equivalence principle light has and inertial mass that is equal to planks constant * the lights frequency divided by the speed of light squared. Thus light can be affected by gravitational fields.
It is not correct, I don't think, to say that you have to bring in quantum theory.
Firstly, although it may be useful to think in terms of photons when considering the concept of mass or momentum of electromagnetic radiation (if indeed it is reasonable to think of it as having relativistic mass), I don't think it's essential. I think the classical theory of electromagnetism predicts electromagnetic waves to have momentum.
Secondly, I don't think it's necessary to think about light having mass when explaining why it is affected by gravity. According to General Relativity, gravitational fields curve spacetime, and light moving through a gravitational field is moving through this curved spacetime.
It is not correct, I don't think, to say that you have to bring in quantum theory.
Firstly, although it may be useful to think in terms of photons when considering the concept of mass or momentum of electromagnetic radiation (if indeed it is reasonable to think of it as having relativistic mass), I don't think it's essential. I think the classical theory of electromagnetism predicts electromagnetic waves to have momentum.
Secondly, I don't think it's necessary to think about light having mass when explaining why it is affected by gravity. According to General Relativity, gravitational fields curve spacetime, and light moving through a gravitational field is moving through this curved spacetime.
QUOTE (Sphinx+Sep 9 2007, 01:29 AM)
Can someone help me with this contradiction?
Light travels at 186,000mps, because it has no mass E=mc² does not apply. Therefore like(photons) can travel at that speed.
Gravity's equation is this: Gravitational force = (G * m1 * m2) / (d2)
m1 and m2 are the masses of the objects.
So gravity attracts mass. Then how does a black hole have a gravitational force great enough to pull something which has no mass?
I've thought a lot about this as well, using less exotic theories,
If we think of gravity as energy, we'd probably think of E=mc^2
If we look at gravity as a force, we would think of F=ma
or to figure out gravitational force Fg=(G*ma*mb)/r^2
*so with these examples, it is fair to conclude that Gravity relies on mass.
The sort-of exception to this is when you look at the theories surrounding space-time curvature. It basically looks at space being similar to a giant rubber sheet and the objects with mass are like metal ball bearings. If enough of them collect in a certain spot they will bend the sheet - causing a depression, in which other masses will fall into. So the 'gravity' is not because of the mass itself - rather the effect the mass has on this rubber sheet. From this point it's simple geometry - the mass falls in the hole. Black holes are supposed to be a point in which enough mass has collected to have cause a 'hole' infinitely deep that absolutely no mass can escape.
I have 1 main problem with that theory - in this model they use space and time in a single continuum (to make this rubber sheet).
Firstly, if time can be given an infinite value - so must space (volume) otherwise you cannot make a single continuum using the 2. This with regards to the model only ...I am aware you could have a finite volume and simply locate an objects position at a certain time.
Secondly, how can time be effected by mass? For this 'warp' in the model to occur - both time and space are curved due to a mass. This is based on a theory of general relativity. This will imply that the quantity of mass will affect the rate at which that mass progresses through time.
Time is 'now', you can't pause it, fast forward or rewind it because the time will always proceed unaltered either relative to the mass or alternatively, it's environment.
To get back to the question ... well, each way you look at it - gravity has a relationship with mass any way you look at it. So if a black hole could attract light or prevent it from escaping, it would mean that light has mass - regardless of how small.
To those that will say, "but there is proof of gravity bending light....ect." ... well consider the possibility of refractive index and nothing more magical than that. The gravitational effect of that object would have attracted masses both large and small, gasses ..you name it, everything. The bending of light would not be a direct effect of the gravity itself on the light but a change in the angle of incidence when the light passes through material with a different refractive index ... it also explains why we get a prismatic effect sometimes too.
I think the thought that black holes can even stop light from escaping creates an unexplained description of what light really is but still makes it fit the model. The model itself has many 'black holes'.
Light travels at 186,000mps, because it has no mass E=mc² does not apply. Therefore like(photons) can travel at that speed.
Gravity's equation is this: Gravitational force = (G * m1 * m2) / (d2)
m1 and m2 are the masses of the objects.
So gravity attracts mass. Then how does a black hole have a gravitational force great enough to pull something which has no mass?
I've thought a lot about this as well, using less exotic theories,
If we think of gravity as energy, we'd probably think of E=mc^2
If we look at gravity as a force, we would think of F=ma
or to figure out gravitational force Fg=(G*ma*mb)/r^2
*so with these examples, it is fair to conclude that Gravity relies on mass.
The sort-of exception to this is when you look at the theories surrounding space-time curvature. It basically looks at space being similar to a giant rubber sheet and the objects with mass are like metal ball bearings. If enough of them collect in a certain spot they will bend the sheet - causing a depression, in which other masses will fall into. So the 'gravity' is not because of the mass itself - rather the effect the mass has on this rubber sheet. From this point it's simple geometry - the mass falls in the hole. Black holes are supposed to be a point in which enough mass has collected to have cause a 'hole' infinitely deep that absolutely no mass can escape.
I have 1 main problem with that theory - in this model they use space and time in a single continuum (to make this rubber sheet).
Firstly, if time can be given an infinite value - so must space (volume) otherwise you cannot make a single continuum using the 2. This with regards to the model only ...I am aware you could have a finite volume and simply locate an objects position at a certain time.
Secondly, how can time be effected by mass? For this 'warp' in the model to occur - both time and space are curved due to a mass. This is based on a theory of general relativity. This will imply that the quantity of mass will affect the rate at which that mass progresses through time.
Time is 'now', you can't pause it, fast forward or rewind it because the time will always proceed unaltered either relative to the mass or alternatively, it's environment.
To get back to the question ... well, each way you look at it - gravity has a relationship with mass any way you look at it. So if a black hole could attract light or prevent it from escaping, it would mean that light has mass - regardless of how small.
To those that will say, "but there is proof of gravity bending light....ect." ... well consider the possibility of refractive index and nothing more magical than that. The gravitational effect of that object would have attracted masses both large and small, gasses ..you name it, everything. The bending of light would not be a direct effect of the gravity itself on the light but a change in the angle of incidence when the light passes through material with a different refractive index ... it also explains why we get a prismatic effect sometimes too.
I think the thought that black holes can even stop light from escaping creates an unexplained description of what light really is but still makes it fit the model. The model itself has many 'black holes'.
QUOTE (Drive The Nail+Aug 30 2009, 05:31 AM)
I think the thought that black holes can even stop light from escaping creates an unexplained description of what light really is but still makes it fit the model. The model itself has many 'black holes'.
If you take it that gravity bends space, then the gravity inside a black hole is sufficient to bend space so much that there are no paths out of it.
If you take it that gravity bends space, then the gravity inside a black hole is sufficient to bend space so much that there are no paths out of it.
Yep, that was always my take on it. Mass bends spacetime. Light follows spacetime curvature. Black holes bend spacetime around in a circle maybe so the light can't get out.
But also, in regards to the mass of a photon, it doesn't have "invariant" rest mass (m₀) like matter does. But it does have relativistic mass (mᵣ). To find the relativistic mass of any particle, both stationary and moving particles, use this:
mᵣ = E / c², where E is:
Somebody please correct me if I am wrong.
But also, in regards to the mass of a photon, it doesn't have "invariant" rest mass (m₀) like matter does. But it does have relativistic mass (mᵣ). To find the relativistic mass of any particle, both stationary and moving particles, use this:
mᵣ = E / c², where E is:
- for a normal particle (nonzero mass), Einstein's Mass-Energy Equivalence Principal, E = m₀ * c²
- for a zero-mass particle like a photon, Plank's Law, E = h * f
- where h is Planck's Constant, measured in Joule-seconds
- and f is frequency, measured in Hz
- frequency being f = c / λ
- where λ is wavelength, measured in meters
- frequency being f = c / λ
Somebody please correct me if I am wrong.
I think you're correct, but until that energy equivalence is turned into mass, the argument is moot.
The photon carries the energy, but we can't freely convert the numbers.
I will accept corrections as well, and thank you.
The photon carries the energy, but we can't freely convert the numbers.
I will accept corrections as well, and thank you.
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