Speed of individual photons cannot exceed speed of light in a vacuum

BBC News - Time travel: Light speed results cast fresh doubts
http://www.bbc.co.uk/news/science-environment-14289114


"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 traveling 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. "

On Jul 26, 9:07*am, Yousuf Khan wrote:
BBC News - Time travel: Light speed results cast fresh doubtshttp://www.bbc.co.uk/news/science-environment-14289114

"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 traveling 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. "

Distance is absolute and light's motion through its emptiness is a
constant.
It is not from frames.

Dear Yousuf Khan:

On Jul 26, 9:07*am, Yousuf Khan wrote:
BBC News - Time travel: Light speed results cast fresh doubts
http://www.bbc.co.uk/news/science-environment-14289114

"Now, a paper in Physical Review Letters shows that
individual photons too are limited to the vacuum speed
limit.

"A population of a large number of individual photons".
http://prl.aps.org/abstract/PRL/v106/i24/e243602
.... which followed from
http://arxiv.org/abs/1102.4998

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 traveling 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. "

David A. Smith

"Yousuf Khan" wrote in message
...
BBC News - Time travel: Light speed results cast fresh doubts
http://www.bbc.co.uk/news/science-environment-14289114


"Now, a paper in Physical Review Letters shows that individual photons too
are limited to the vacuum speed limit.

duh...... it has always been that way.


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 traveling faster than light. It is violation
of this causality that would, in principle, permit time travel.

go read his paper.


While the limit in vacuum is a fixed number - some 300,000km per second -
the speed of light can vary widely in different materials. "

almost right, but not. It can only go slower that c.

On 7/26/11 11:07 AM, Yousuf Khan wrote:
BBC News - Time travel: Light speed results cast fresh doubts
http://www.bbc.co.uk/news/science-environment-14289114



Experiment shows time travel impossible
http://www.abc.net.au/science/articl...25/3277064.htm

Hong Kong physicists say they have proved that a single photon obeys
Einstein's theory that nothing can travel faster than the speed of
light, demonstrating that time travel is impossible.

See: http://www.abc.net.au/science/articl...25/3277064.htm

On Jul 26, 7:59*pm, dlzc wrote:
Dear Yousuf Khan:

On Jul 26, 9:07*am, Yousuf Khan wrote: BBC News - Time travel: Light speed results cast fresh doubts

http://www.bbc.co.uk/news/science-environment-14289114



"Now, a paper in Physical Review Letters shows that
individual photons too are limited to the vacuum speed
limit.

"A population of a large number of individual photons".http://prl.aps.org/abstract/PRL/v106/i24/e243602
... which followed fromhttp://arxiv.org/abs/1102.4998

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 traveling 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. "

David A. Smith

------------------------
quote from that link:
------------------
Physicists have confirmed the ultimate speed limit for the packets of
light called photons - making time travel even less likely than
thought.
end of quote:

it is from 2011

they are talking about
packets of lights''

and the title is
INDIVIDUAL PHOTONS ''

just tell those thieves that
in order of not being thieves thsy have to
mention the copyright er of the
'real single photon'

untill 2010 a single photon energy was donsidered to be

E -=hf !!
in feb 2010
an anonymous called Y. Porat
a member of this humble Ng
was dsicovering that
the real single photon energy is not
E=hf
but

E min photon = hf times n
while n
0 n 1.0000

it was done in the historic thread called

"A better new definition of the real single photon plus a simple
experiment""

later that anonymous Y.Porat
went even further and defined numerically
and more specifically the smallest energy
of the real single photon energy as

E single photon = hf times (the
SCALAR part of PLANCK TIME
and his next step was to divide it by c^

TO GET THE MASS - THE ONLY MASS-
OF THE REAL SINGLE PHOTON
to be
about
exp -93 kilograms
and added and indicated that
such tiny mass can never be detected
by human beings tools
and that is one of the reasons
why
what was called before me
a single photon
will be considered from 2010 and further according me
and other real physicists

''A HUGE BUNDLE
OF SINGLE PHOTONS '''

all parrot physicist before me
considered mistakenly the mass of the photon
to be '''theoretically as zero''' !!

IT IS NOT ZERO
AND IT IS NOT RELATIVISTIC

and that anonymous even expanded his
insight to claim

NO MASS - THE ONLY MASS-NO REAL PHYSICS !!

which is a new revolution in modern physics !!!

TIA
Y.Porat (the anonymous physicist ) ...
-----------------------------------------

On Jul 26, 2:49*pm, Sam Wormley wrote:
On 7/26/11 11:07 AM, Yousuf Khan wrote:

BBC News - Time travel: Light speed results cast fresh doubts
http://www.bbc.co.uk/news/science-environment-14289114

Experiment shows time travel impossible
* *http://www.abc.net.au/science/articl...25/3277064.htm

Hong Kong physicists say they have proved that a single photon obeys
Einstein's theory that nothing can travel faster than the speed of
light, demonstrating that time travel is impossible.

See:http://www.abc.net.au/science/articl...25/3277064.htm

Is the first photon the same as the target or retro-reflected photon?

On Jul 26, 9:07*am, Yousuf Khan wrote:
BBC News - Time travel: Light speed results cast fresh doubtshttp://www.bbc.co.uk/news/science-environment-14289114

"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 traveling 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. "

So what material or medium is the hard vacuum of the IGM made of?

On 26/07/2011 1:59 PM, dlzc wrote:
Dear Yousuf Khan:

On Jul 26, 9:07 am, Yousuf wrote:
BBC News - Time travel: Light speed results cast fresh doubts
http://www.bbc.co.uk/news/science-environment-14289114

"Now, a paper in Physical Review Letters shows that
individual photons too are limited to the vacuum speed
limit.

"A population of a large number of individual photons".
http://prl.aps.org/abstract/PRL/v106/i24/e243602
... which followed from
http://arxiv.org/abs/1102.4998

It almost seems like a "well, duh" study, but quantum mechanics seems to
bypass a lot of relativistic rules, and individual photons are most
definitely quantum mechanical in nature.

I'm wondering if individual photons do exceed the speed of light, but we
just don't detect them as they get filtered out by the direction of
time? That is to say that time polarizes the photons.

Yousuf Khan

Dear Yousuf Khan:

On Jul 27, 8:33*am, Yousuf Khan wrote:
On 26/07/2011 1:59 PM, dlzc wrote:
On Jul 26, 9:07 am, Yousuf *wrote:
BBC News - Time travel: Light speed results cast fresh doubts
http://www.bbc.co.uk/news/science-environment-14289114

"Now, a paper in Physical Review Letters shows that
individual photons too are limited to the vacuum speed
limit.

"A population of a large number of individual photons".
http://prl.aps.org/abstract/PRL/v106/i24/e243602
... which followed from
http://arxiv.org/abs/1102.4998

It almost seems like a "well, duh" study, but quantum
mechanics seems to bypass a lot of relativistic rules, and
individual photons are most definitely quantum mechanical
in nature.

You are right, it had to be done.

I'm wondering if individual photons do exceed the speed of
light, but we just don't detect them as they get filtered out
by the direction of time? That is to say that time polarizes
the photons.

Quantum mechanics has "real propagating" photons as a series of
virtual photons. So maybe the question is moot.

David A. Smith