Posted on 07/27/2011 2:26:16 PM PDT by SeekAndFind
Physicists have confirmed the ultimate speed limit for the packets of light called photons - making time travel even less likely than thought.
The speed of light in vacuum is the Universe's ultimate speed limit, but experiments in recent years suggested that single photons might beat it.
If they could, theory allows for the prospect of time travel.
Now, a paper in Physical Review Letters shows that individual photons too are limited to the vacuum speed limit.
That means that photons maintain the principle of causality laid out in Einstein's theory of special relativity - that is, an event's effect cannot precede its cause by travelling faster than light. It is violation of this causality that would, in principle, permit time travel.
While the limit in vacuum is a fixed number - some 300,000km per second - the speed of light can vary widely in different materials.
These differences explain everything from why a straw looks bent in a glass of water to experiments in cold gases of atoms in which light's speed is actively manipulated.
Some of those experiments showed "superluminal" behaviour, in which photons travelled faster than the speed of light in a given medium.
It remained, however, to determine whether or not individual photons could exceed the vacuum limit.
(Excerpt) Read more at bbc.co.uk ...
Time does not exist. There is only the present.
I HAVE TRAVELED HERE FROM THE FUTURE TO DISPUTE THIS.
Perhaps only in this Universe..
Considering that they can’t seem to get global warming straight, I’ll reserve judgement on anything more complicated.
But do Gravitons travel faster than the speed of light out of a black hole?
“Say it ain’t so, McFly!”
I have traveled here from the past to dispute this.
I know its possible simply for the Bible. Its in there. They just don’t say it in those words.
Looks like I’m gonna have to unpack. What will I do with my futuristic three piece suit, though?
Yea, yea right, but what about 2 entangled photons able to communicate their spin state instantaneously irregardless of their distance?
and in normal space, that’s why we need to discover how to use subspace Geordi’s giving a lecture on the history of that discovery next Tuesday in Ten Forward...
Please go back and bring the next Powerball number. Without it, you wasted the trip.
Beam me up, Scotty.
I would reserve judgment, too. But "Global Warming" is much, much more complicated. This is basic physics. We can attempt direct measurements and model the mathematics on the back of an envelope. The conceptual hurdles required for the human mind to grasp the physics are far more daunting than the cartoonish caricature of "Global Warming" presented by Al Gore and the mainstream media.
Global Warming Theory involves a string of concatenated hypotheses (what was it Willian of Occam had to say about these?), some of which are straightforward basic physics (e.g., carbon dioxide absorbs infrared radiation) and easily validated. Some of the hypotheses associated with GWT, are dependent on tenuous and poorly understood large scale atmosphere physics and involve critical parameters whose values are not known with enough precision to reliably even predict the sign of their effect.
A simple analogy might be eclipses and rain. Astronomers can reliably predict eclipses 10,000 years into the future. Meteorologists cannot tell you if it is going to rain two weeks from today. Basic physics is like astronomy; GWT is like meteorology.
Time is an artifact of motion. Without motion time would not exist.
I'll have to remember this the next time my wife yells at me for something that I haven't done yet but that she knows I'm going to do.
But do Gravitons travel faster than the speed of light out of a black hole?
+++++++++++++++++
As far as I know, there is no experimental evidence for the existence of gravitons. Theory says we should see them but so far no such luck.
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