CITE
We at Fermilab deal everyday with particles moving faster than the speed of light!
In fact, we use them to detect some fast particles moving through our detectors.
You might say: "What?? In the previous 12 pages you convinced me that
there is no such thing as an object moving faster than the speed of light!".
Don't worry: you are right. The trick is that I carefully left out in the first
paragraph the words IN A VACUUM when I said "particles moving faster
than the speed of light!" Got it? ...
/CITE
http://home.fnal.gov/~pompos/light/light_page14.html

It seems to me that this Fermilab scientist is meaning that
the vacuum is rather a limiting environment for the light.

How do you interpret what this scientist is saying?

In article , "optman" wrote:

CITE
We at Fermilab deal everyday with particles moving faster than the speed of
light!
In fact, we use them to detect some fast particles moving through our
detectors.
You might say: "What?? In the previous 12 pages you convinced me that
there is no such thing as an object moving faster than the speed of light!".
Don't worry: you are right. The trick is that I carefully left out in the
first
paragraph the words IN A VACUUM when I said "particles moving faster
than the speed of light!" Got it? ...
/CITE
http://home.fnal.gov/~pompos/light/light_page14.html

It seems to me that this Fermilab scientist is meaning that
the vacuum is rather a limiting environment for the light.

How do you interpret what this scientist is saying?


Light travels slower in a medium other then vacuum. Therefore, if we have a
material called examplium where the speed of light is 0.75c, we can accelerate
particles to travel through it at 0.8c and it will be travelling faster then
the light in the medium.

See Cerenkov Radiation.

--
COOSN-174-07-82116: Official Science Team mascot and alt.astronomy's favourite
poster (from a survey taken of the saucerhead high command).

Official maintainer of the supra-cosmic space fluid pump (Mon and Tues only).

"optman" wrote in message
...
CITE
We at Fermilab deal everyday with particles moving faster than the speed
of light!
In fact, we use them to detect some fast particles moving through our
detectors.
You might say: "What?? In the previous 12 pages you convinced me that
there is no such thing as an object moving faster than the speed of
light!".
Don't worry: you are right. The trick is that I carefully left out in the
first
paragraph the words IN A VACUUM when I said "particles moving faster
than the speed of light!" Got it? ...
/CITE
http://home.fnal.gov/~pompos/light/light_page14.html

It seems to me that this Fermilab scientist is meaning that
the vacuum is rather a limiting environment for the light.

How do you interpret what this scientist is saying?

Light travels fastest in a vacuum, and slower in other mediums. When
scientists say "the speed of light", the often mean "the speed of light in
vacuum". When traveling through other mediums, particles can move faster
than light can travel through the same medium. When particles travel faster
than light in a medium, they radiate light in the form of Cerenkov
radiation. Particles can never travel faster than light in a vacuum.

Carl G.

On Jun 7, 10:19 am, "optman" wrote:
CITE
We at Fermilab deal everyday with particles moving faster than the speed of light!
In fact, we use them to detect some fast particles moving through our detectors.
You might say: "What?? In the previous 12 pages you convinced me that
there is no such thing as an object moving faster than the speed of light!".
Don't worry: you are right. The trick is that I carefully left out in the first
paragraph the words IN A VACUUM when I said "particles moving faster
than the speed of light!" Got it? ...
/CITEhttp://home.fnal.gov/~pompos/light/light_page14.html

It seems to me that this Fermilab scientist is meaning that
the vacuum is rather a limiting environment for the light.

How do you interpret what this scientist is saying?

No, he's not saying that.
He's saying there is a universal speed limit.
It so happens that light travels at that speed limit when it traveling
in vacuum.
In material media, light (as a whole, not as individual photons)
travels *slower* than that speed limit.
It also happens sometimes that other particles travel through a
material medium at a speed faster than light's but lower than the
universal speed limit.

PD

On Jun 7, 10:19 am, "optman" wrote:
CITE
We at Fermilab deal everyday with particles moving faster than the speed of light!
In fact, we use them to detect some fast particles moving through our detectors.
You might say: "What?? In the previous 12 pages you convinced me that
there is no such thing as an object moving faster than the speed of light!".
Don't worry: you are right. The trick is that I carefully left out in the first
paragraph the words IN A VACUUM when I said "particles moving faster
than the speed of light!" Got it? ...
/CITEhttp://home.fnal.gov/~pompos/light/light_page14.html

It seems to me that this Fermilab scientist is meaning that
the vacuum is rather a limiting environment for the light.

How do you interpret what this scientist is saying?

The "speed of light" is the speed at which
electromagnetic waves propagate. You can calculate
this from Maxwell's Equations to be
c = 1/sqrt(\mu \epsilon)
where \mu and \epsilon are the magnetic permeability
and electric permitivity, respectively. In
a vacuum, these both have their minimum values
(\mu_0 and \epsilon_0), and so you get a maximum
value of 3e8 m/s = c. In any other material, they
will be larger (and, in general, frequency
dependent), and the velocity will be lower.

The ratio of these velocities is the
index of refraction. Typical indices of
refraction for transparent materials are
on the order of 1.5 (meaning light
will propagate at about 2/3c)
http://hyperphysics.phy-astr.gsu.edu...les/indrf.html
Using a gas and controlling the pressure,
you can get an index of refraction arbitrarily
close to 1.

If a charged particle enters such a medium going
*faster* than the local speed of light (but NEVER
faster than c), it will emit a "shock wave",
of a burst of light, with a flat frequency
spectrum. This is called "Cherenkov radiation".

This is a very valuable tool experimentally,
because Cherenkov radiation depends on the
*velocity* of the particle, whereas magnetic
spectrometers measure *momentum*. If you
separately measure the momentum and
velocity, you know the mass, so Cherenkov
detectors play an important role in particle
identification. For example, they are often
used to distinguish pions, kaons, and protons
in high energy physics experiments.

-jc

"optman" wrote in message
...
How do you interpret what this scientist is saying?

http://www.google.co.uk/search?hl=en...ow+light&meta=

On Thu, 07 Jun 2007 10:06:32 -0700, PD wrote:

On Jun 7, 10:19 am, "optman" wrote:
CITE
We at Fermilab deal everyday with particles moving faster than the speed of light!
In fact, we use them to detect some fast particles moving through our detectors.
You might say: "What?? In the previous 12 pages you convinced me that
there is no such thing as an object moving faster than the speed of light!".
Don't worry: you are right. The trick is that I carefully left out in the first
paragraph the words IN A VACUUM when I said "particles moving faster
than the speed of light!" Got it? ...
/CITEhttp://home.fnal.gov/~pompos/light/light_page14.html

It seems to me that this Fermilab scientist is meaning that
the vacuum is rather a limiting environment for the light.

How do you interpret what this scientist is saying?

No, he's not saying that.
He's saying there is a universal speed limit.
It so happens that light travels at that speed limit when it traveling
in vacuum.
In material media, light (as a whole, not as individual photons)
travels *slower* than that speed limit.
It also happens sometimes that other particles travel through a
material medium at a speed faster than light's but lower than the
universal speed limit.

Speed wrt what Draper?

.......You sure are a slow learner...


PD



www.users.bigpond.com/hewn/index.htm

Einstein's Relativity - the greatest HOAX since jesus christ's virgin mother.

On Jun 8, 3:59 am, HW@....(Henri Wilson) wrote:
On Thu, 07 Jun 2007 10:06:32 -0700, PD wrote:
On Jun 7, 10:19 am, "optman" wrote:
CITE
We at Fermilab deal everyday with particles moving faster than the speed of light!
In fact, we use them to detect some fast particles moving through our detectors.
You might say: "What?? In the previous 12 pages you convinced me that
there is no such thing as an object moving faster than the speed of light!".
Don't worry: you are right. The trick is that I carefully left out in the first
paragraph the words IN A VACUUM when I said "particles moving faster
than the speed of light!" Got it? ...
/CITEhttp://home.fnal.gov/~pompos/light/light_page14.html

It seems to me that this Fermilab scientist is meaning that
the vacuum is rather a limiting environment for the light.

How do you interpret what this scientist is saying?

No, he's not saying that.
He's saying there is a universal speed limit.
It so happens that light travels at that speed limit when it traveling
in vacuum.
In material media, light (as a whole, not as individual photons)
travels *slower* than that speed limit.
It also happens sometimes that other particles travel through a
material medium at a speed faster than light's but lower than the
universal speed limit.

Speed wrt what Draper?

The observer, Henri. Haven't I told you that before?


......You sure are a slow learner...



PD

www.users.bigpond.com/hewn/index.htm

Einstein's Relativity - the greatest HOAX since jesus christ's virgin mother.- Hide quoted text -

- Show quoted text -

optman wrote:
CITE
We at Fermilab deal everyday with particles moving faster than the speed of light!
In fact, we use them to detect some fast particles moving through our detectors.
You might say: "What?? In the previous 12 pages you convinced me that
there is no such thing as an object moving faster than the speed of light!".
Don't worry: you are right. The trick is that I carefully left out in the first
paragraph the words IN A VACUUM when I said "particles moving faster
than the speed of light!" Got it? ...
/CITE
http://home.fnal.gov/~pompos/light/light_page14.html

It seems to me that this Fermilab scientist is meaning that
the vacuum is rather a limiting environment for the light.

How do you interpret what this scientist is saying?

This is a common occurrence happening constantly in the atmosphere above
us. Cosmic rays and gamma rays passing though the earth's atmosphere
commonly exceed the speed of light in the atmosphere. That causes
the fast particles to dump energy in the form of very brief flashes of
light called Cherenkov radiation. Those flashes of light are observable
with photomultiplier tubes and are used to observe and measure the
location of astronomical objects which emit gamma rays.

Google "Cherenkov radiation" for more information.

All the "scientist" is doing is playing with the common and and
incorrect statement "Matter can't travel faster than light". It can in
any medium with a refractive index greater than unity.

On Fri, 08 Jun 2007 13:44:03 GMT, Sam Wormley wrote:

Henri Wilson wrote:


Speed wrt what Draper?


The speed of light is c wrt all inertial observers, Henri! It is emprically
so. Boy, you sure have a lot of Fumbles Henri!
http://www.google.com/search?q=Henri...s.pand ora.be

Never measured, Wormy....



www.users.bigpond.com/hewn/index.htm

Einstein's Relativity - the greatest HOAX since jesus christ's virgin mother.