Photons have no mass, therefore they can travel at the speed of light (mass cannot increase if you start with 0). Then how do black holes' gravity suck photons back into the black hole itself? In order for gravity to work, an object of a mass must be present.
2007-03-27 07:36:02 · 8 answers · asked by Anonymous in Science & Mathematics ➔ Physics
Not according to general relativity.
Mass bends the space time around it, so that light (following straight line path) seems to curve.
2007-03-27 07:38:30 · answer #1 · answered by Anonymous · 1⤊ 0⤋
The classic 3D analogy of Einstien's 4D space-time is that of a trampoline with a bowling ball resting in the middle of it. The ball is a heavy mass (such as star or planet) and the trampoline is space. The "space" curves toward and around the ball. If you were to roll a golf ball across the trampoline such that it passes close to the bowling ball, the path that the golf ball will travel will bend as it passes the bowling ball. A black hole wouldn't be a 16lb ball, it would be a ball weighing several tons; so you can imagine what the surface of the tampoline would look like.
The result is that the shortest distance between two points is not a straight line but rather a geodesic relative to the nearest space-time continuum. :)
2007-03-27 15:28:17 · answer #2 · answered by Tim K 2 · 0⤊ 0⤋
According to Einsteins theory of relativity, E=mc^2, so anything that has energy effectively has mass. Photons have energy according to another equation (E=hf you dont need to understand that, it means that X rays have more energy than visible light or radio waves), so they have a mass and are therefore attracted towards any mass, but its only with really massive things (ie black holes) that the effect is enough to be noticeable
2007-03-27 14:46:09 · answer #3 · answered by Anonymous · 0⤊ 0⤋
What we call the "force" of gravity is actually the bending of space caused by the presence of mass. When the mass is large enough, space is bent back on itself. Everything in the universe must follow the geometry of space, including photons of light.
2007-03-27 14:53:19 · answer #4 · answered by Chug-a-Lug 7 · 0⤊ 0⤋
Photons do have energy, therefore a tiny amount of mass. Something like 6 x 10^-15 electron volts. Divide by the spped of light squared and you get a negligible amount of mass for rest mass values, but it is not zero.
2007-03-27 14:46:26 · answer #5 · answered by loon_mallet_wielder 5 · 0⤊ 0⤋
The photon has a REST MASS of zero. Its only mass is its relativistic mass. It has been demonstrated that light is bent by a gravitational field.
2007-03-27 21:10:10 · answer #6 · answered by Frank N 7 · 0⤊ 0⤋
Gravity bends the space-time. The photon is not effectively "attracted" by the black hole but is "caged" by the space distortion.
2007-03-27 14:52:16 · answer #7 · answered by MadScientist 2 · 0⤊ 1⤋
Photons don't have mass, but they do have energy--and as Einstein famously proved, mass and energy are really the same thing.
2007-03-27 14:45:20 · answer #8 · answered by perry j 2 · 0⤊ 0⤋