light
#1
Posted 2008-June-07, 10:23
#2
Posted 2008-June-07, 11:16
If you look up "photon" and "mass" at Wikipedia you can get lots of details about these concepts.
#3
Posted 2008-June-07, 12:03
#4
Posted 2008-June-07, 13:22
George Carlin
#5
Posted 2008-June-07, 13:38
As for tv, screw it. You aren't missing anything. -- Ken Berg
I have come to realise it is futile to expect or hope a regular club game will be run in accordance with the laws. -- Jillybean
#7
Posted 2008-June-07, 15:11
luke warm, on Jun 7 2008, 01:03 PM, said:
The curvature of space-time causes the light to follow a "bent" path. Once the singularity (black hole) is massive enough, the "bend" will not allow anything that crosses its "surface" to move away from the source. The light (or anything else) "falls" into the singularity.....to an end that even physicists tend not to ponder...
#8
Posted 2008-June-07, 15:13
#9
Posted 2008-June-07, 15:15
Jlall, on Jun 7 2008, 03:18 PM, said:
I would have thought that dealt a "lemon", you might try to make some lemonade with a "squeeze"....lol
#10
Posted 2008-June-07, 16:50
Al_U_Card, on Jun 7 2008, 10:11 PM, said:
I never understood the explanation that black holes have too strong gravity fields to allow things to escape. After all, when a comet approaches the sun it will bounce back with the same (give or take mass loss due to evaporation) energy as it came with, and according to classical mechanics it doesn't matter how heavy the central body is. Sound as if I would understand it if I could understand general relativity, lol.
#11
Posted 2008-June-07, 17:48
This is how I also see the quantum tunneling phenomenon but with those little virtual buggers seeing the "up" as "down" so that they CAN get out...
#13
Posted 2008-June-07, 18:18
Al_U_Card, on Jun 7 2008, 04:11 PM, said:
luke warm, on Jun 7 2008, 01:03 PM, said:
The curvature of space-time causes the light to follow a "bent" path. Once the singularity (black hole) is massive enough, the "bend" will not allow anything that crosses its "surface" to move away from the source. The light (or anything else) "falls" into the singularity.....to an end that even physicists tend not to ponder...
this is a little confusing to me... barmar said there is what's termed 'relativistic mass' present in light, but no actual (resting) mass... does this bent path you speak of mean there is "friction" of a sort in light's path? even if that were the case, if light has no mass there would seem to me to be no net effect... i'm getting a headache
#14
Posted 2008-June-07, 20:39
Does that help, or should I get you some Advil?
#15
Posted 2008-June-07, 23:41
George Carlin
#16
Posted 2008-June-08, 04:23
luke warm, on Jun 8 2008, 01:18 AM, said:
The relativistic mass of light is very real - it can be seen when the sight-line to a star is very close to that of the Sun and it looks as if the star has moved away from its normal position - what happens is an optimal illusion caused by the light from the start being bent by the gravity field of the Sun. Another example is when sunlight pushes small objects such as spaceships and comets' tails away, something that can be explained by the light's momentum being transfered to the object. A third example is gamma decay where the emitting atoms suffer a mass loss which can only be accounted for if the gamma ray took some of the mass with it.
So there is nothing mystical about the mass of light, and it is not something that requires extreme circumstances such as black holes to take effect.
Everything gets trapped in black holes - again, there is nothing special about light. Apparently it is better explained in terms of the geometry of space rather than in terms of forces - a "straight" line within the event horizon of a black hole is a circle confined to the black hole.
#17
Posted 2008-June-08, 07:11
#18
Posted 2008-June-08, 09:02
Also, the speed of light is only a constant for the purposes of formulae like e=mc^2. If I remember correctly the "c" they use is the speed of light in a vacuum. It does vary slightly in different media, just like sound.
Nick
#19
Posted 2008-June-08, 09:20
#20
Posted 2008-June-08, 09:31
Nick