So we can use General Relativity to calculate exactly how far it bends. We can also use it to calculate exactly how clocks slow down in gravitational wells, and how quickly elliptical orbits precess, and how rapidly binary pulsars spiral towards each other because of energy lost to gravitational radiation. Believe it or not, that last one is by far the most precisely measured of all the quantities.
It is just proof that gravity exisists, and that light probably has some sort of mass.
But it doesn't have any mass; we know that from completely independent measurements. But even so, if light had a tiny mass (actually, no mass is necessary even in this classical picture; but I leave it for the sake of argument) and gravity were a Newton-style inverse square law like electromagnetism, light rays would indeed bend, but the bending would be a factor of two smaller than is observed.
What is gravity?
It's the curvature of spacetime.
PS, without my work, you may have not had that super Hubble picture you posted.
And I thank you for it. But I suppose you still think me an ingrate for disagreeing with you.
==================
This may also be of interest, but it seems to have disappeared of the FreeRepublic, at least I can no longer find it on a search.
-=------------
010812 Harvard scientists say theyve stopped light
2001-08-12
8/12/01 12:57:56 PM
Harvard scientists say they've stopped light: Speed of light is zero
Miscellaneous Miscellaneous Keywords: SCIENCE?? OR JUNK.
Source: Boston Glob
Published: 1/18/2001 Author: Douglas Bailey
Posted on 01/18/2001 14:18:46 PST by rface
Two years ago, Harvard scientists stunned the world of physics when they said they slowed the speed of light to about 40 miles per hour. Now, they report they have brought light to a complete stop in an achievement that may pave the way for ultra-fast computers that are impervious to hackers.
In separate reports scheduled for release in two scientific journals later this month, the physicists - Dr. Ronald L. Walsworth and Dr. Mikhail D. Lukin of the Harvard-Smithsonian Center for Astrophysics, and Dr. Lene Vestergaard Hau of Harvard University and the Rowland Institute for Science in Cambridge - say they have actually tamed light, holding it, then letting it go on command.
The ability to bring light, which normally travels at 186,000 miles per second, to a standstill is expected to precipitate major advances in quantam computing, which theoretically relies on the ability to harness and delay light. Such computers would be phenomenally faster than today's swiftest computer and their security could be guaranteed.
Walsworth and Lukin's paper is scheduled for publication in the Jan. 29 issue of Physical Review Letters. Hau will detail her findings in the the journal Nature.
This story ran on page A3 of the Boston Globe on 1/18/2001.
--------------------------------------------------------------------------------
Maybe this makes no sense because its from Harvard.
Ashland, Missouri
1 Posted on 01/18/2001 14:18:46 PST by rface (RFacemyer@msn.com)
[ Reply | Private Reply | Top | Last ]
To: rface
If I'm understanding this correctly (and I misunderstand alot, believe me). This has the potential, as the article states, to open up the creation of quantum computing. Sort of like a light driven transistor. This could get around a number of problems/limitations with our electricity (electron) driven transistors. Of course all that might prove to be unworkable and it will be just a cool trick.
8 Posted on 01/18/2001 14:25:04 PST by Tis The Time''s Plague
[ Reply | Private Reply | To 1 | Top | Last ]
--------------------------------------------------------------------------------
To: rface
If this is true, we can soon say goodbye to computing as we know it, and we will soon have computers more akin to what we would see on the starship Enterprise.
The great thing about photons, is that the current restrictions to computational speed, (heat, resistance, EMF)are history. If we can control a photon in the same way we do now with electrons, this is going to be a whole new world.
10 Posted on 01/18/2001 14:26:28 PST by innocentbystander
[ Reply | Private Reply | To 1 | Top | Last ]
---------
That is circular logic, and doesn't really explain anything much to me. Gravity is a force, space/time are measures of variations. I have already figured out, to my satisfaction, that time travel is impossible, as it must of necessity encompass space travel - if we travel back in time, the earth would no longer be in the same place as it was at that time, therefore, we must travel back in time and space.
"PS, without my work, you may have not had that super Hubble picture you posted. And I thank you for it. But I suppose you still think me an ingrate for disagreeing with you."
Not at all. It is one of the things I am very proud of out of my three years working at Kennedy Space Center. I designed a special system, first used on the Hubble launch, which saved the day and allowed them to make their very critical launch window. Otherwise, the Hubbble could have been delayed for years, if it made it up at all.
As far as disagreeing - you are in your element here, not me. I am just trying to get some answers, to my satisfaction, that can give me an idea in laymans terms, what gravity is. At present, I have only seen offers of measurements of gravity as examples. EG, light is composed of photons, and measured in mph or what ever. What is gravity composed of?