| Author |
Message |
Ken Smith
Guest
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 Posted:
Sat Feb 05, 2005 4:11 pm Post subject:
Re: breaking the speed of light article on howstuffworks.com |
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In article <pan.2005.02.05.03.23.48.430568@att.bizzzz>,
keith <krw@att.bizzzz> wrote:
[...]
| Quote: | I designed a logic level convert circuit once that I spec'd with a
negative delay, at least until someone read it. I was *forced* to do
rise-times from 20-80 and delays from 50-50. The threshold wasn't at 50,
so until I showed the PHBs how stupid their requirements were, it had a
negative delay. ...and no, no electrons were hurt in testing the circuit.
|
I actually got a spec from some fairly smart people that said that one
pulse had to be produced before the other. The later pulse was called the
"trigger" and was supposed to be the external input to the circuit.
What they really wanted was a circuit that made two pulses that partly
overlapped. They didn't really want to have to provide the "trigger"
input.
--
--
kensmith@rahul.net forging knowledge
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Ken Smith
Guest
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| Posted:
Sat Feb 05, 2005 4:23 pm Post subject:
Re: breaking the speed of light article on howstuffworks.com |
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In article <6di8019u05ptqodkm919q7596ekj9j5nre@4ax.com>,
John Larkin <jjSNIPlarkin@highTHISlandPLEASEtechnology.XXX> wrote:
[...]
| Quote: | You can build a fast shutter close to a source that only lets light
through for a nanosecond or less, and then measure arrival times some
distance away.
|
I don't think this version of the experiment can be actually done. The
"measure the arrival times" part is not easy unless the shutter and the
detector are closer together than the length of the trip. If they aren't
there will be trouble making the shutter and the timer be in sync.
| Quote: | Or do interferance experiments, which are exquisitely
sensitive to the speed of light. There are lots of techniques that
could detect ftl photons if they existed.
|
This is also likely to be the easier way to do it. You need a tunable
laser so you can measure the change in interferance with wave length. If
not you will have trouble proving you are not just off by N cycles.
--
--
kensmith@rahul.net forging knowledge |
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Ken Smith
Guest
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| Posted:
Sat Feb 05, 2005 4:30 pm Post subject:
Re: breaking the speed of light article on howstuffworks.com |
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In article <36jnsiF52nelrU1@individual.net>, Gareth <me@privacy.net> wrote:
[...]
| Quote: | Einstein's theory of Special Relativity prevents anything with mass or
information from travelling faster than light.
|
Actually it prevents anything that is not already FTL from getting there.
If something is FTL it can't slow down and has weird backwards physics.
You can get what appears to be FTL motion by projecting a image onto a far
away screen and rotating the projector. Since photon etc don't wear dog
tags, you can get some funny measurements if you aren't careful.
--
--
kensmith@rahul.net forging knowledge
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Gareth
Guest
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| Posted:
Sat Feb 05, 2005 5:10 pm Post subject:
Re: breaking the speed of light article on howstuffworks.com |
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~~SciGirl~~ wrote:
| Quote: | As John Larkin said... "Same sort of thing, altering the shape of a
pulse and thinking that makes it go faster. Optically, an oscillatory
burst can appear to
exceed C if you sort of stand back and squint, but no photons are going
faster than C."
You can never be positive. If you cannot measure the position and
velocity of the photons simultaneously, how can you be sure they are
not going faster than c? Nobody can really measure the speed of the
particles as they exited the container, because you'd need to specify
the position defined as "exiting the container." This could disprove
the experiment, but it could also disprove the arguments of everyone
who does not believe the photons moved faster than c.
|
Einstein's theory of Special Relativity prevents anything with mass or
information from travelling faster than light. It is possible that one
day this theory will be proved wrong, but it has been validated by many
experiments over the last 100 years. The FAQ on Wang's webpage states
that his experiment does NOT contradict current theory, and cannot be
used to send information faster than light. See:
http://www.neci.nj.nec.com/homepages/lwan/faq.htm
For a very good demonstration of how light can appear to travel faster
than light have a look at the Java applet in the link below:
http://gregegan.customer.netspace.net.au/APPLETS/20/20.html
The Java applet also shows what happens if you try to send information
by modulating the beam.
There is some more information on superluminal phenomena here:
http://scienceworld.wolfram.com/physics/Superluminal.html
Gareth.
--
-----------------------------------------------------------------------
To reply to me directly:
Replace privacy.net with: totalise DOT co DOT uk and replace me with
gareth.harris |
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Winfield Hill
Guest
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| Posted:
Sat Feb 05, 2005 5:52 pm Post subject:
Re: breaking the speed of light article on howstuffworks.com |
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Ben Bradley wrote...
| Quote: |
SciGirl wrote:
Mathew Orman, FTL dream? I must have missed something.
Short story, he was a guy here telling about his cables he tried to
sell on ebay for an outrageous price, that he claimed could transmit
a signal faster than the speed of light.
|
Yes, he offered the original laboratory cable at a high price, as a
sort of historical valuable artifact, but at about the same time he
also offered a student cable for $10, IIRC. There were no bidders.
--
Thanks,
- Win |
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Robert Baer
Guest
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| Posted:
Sat Feb 05, 2005 7:38 pm Post subject:
Re: breaking the speed of light article on howstuffworks.com |
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Fred Bartoli wrote:
| Quote: |
"John Larkin" <jjlarkin@highSNIPlandTHIStechPLEASEnology.com> a écrit dans
le message de news:jo3801p4360lkn2jqq5mtpajptms0k6uph@4ax.com...
On Fri, 04 Feb 2005 21:09:37 GMT, nico@puntnl.niks (Nico Coesel)
wrote:
"~~SciGirl~~" <palmtree117@juno.com> wrote:
Here it is, I located it again.
"In Wang's experiment, a pulse of light passed through a small
chamber filled with atoms of elemental cesium. A light beam traveling
through such a medium has two different velocities - a velocity for
the individual light waves in the beam and a group velocity for the
entire beam. Oddly, some light waves in the beam can actually travel
backward for miniscule amounts of time, creating a sort of "tail"
behind forward-moving waves. As such, a light wave and its tail can
leave the gas cavity at different times, creating the effect that the
light beam has left the cavity before it's even entered."
This sounds a lot like the electrical effects observed by our friend
Mathew Orman during his FTL dream.
Same sort of thing, altering the shape of a pulse and thinking that
makes it go faster. Optically, an oscillatory burst can appear to
exceed C if you sort of stand back and squint, but no photons are
going faster than C.
Well, I've just done mucho faster than light with a 100kHz sine wave. Pretty
easy: don't terminate the line and once the transient is settled (which you
can't notice) the sine wave "travels FTL" (read the phase shift is much
smaller than what light speed would imply for the line length). Terminate
the line and the effect is gone.
This saved me on a precision phase measurement board.
--
Thanks,
Fred.
|
Bullshit.
It is clear that you do not understand what you thought you saw. |
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Robert Baer
Guest
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| Posted:
Sat Feb 05, 2005 7:53 pm Post subject:
Re: breaking the speed of light article on howstuffworks.com |
|
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keith wrote:
| Quote: |
On Fri, 04 Feb 2005 16:14:05 -0800, John Larkin wrote:
On Fri, 04 Feb 2005 21:09:37 GMT, nico@puntnl.niks (Nico Coesel)
wrote:
"~~SciGirl~~" <palmtree117@juno.com> wrote:
Here it is, I located it again.
"In Wang's experiment, a pulse of light passed through a small
chamber filled with atoms of elemental cesium. A light beam traveling
through such a medium has two different velocities - a velocity for
the individual light waves in the beam and a group velocity for the
entire beam. Oddly, some light waves in the beam can actually travel
backward for miniscule amounts of time, creating a sort of "tail"
behind forward-moving waves. As such, a light wave and its tail can
leave the gas cavity at different times, creating the effect that the
light beam has left the cavity before it's even entered."
This sounds a lot like the electrical effects observed by our friend
Mathew Orman during his FTL dream.
Same sort of thing, altering the shape of a pulse and thinking that
makes it go faster. Optically, an oscillatory burst can appear to
exceed C if you sort of stand back and squint, but no photons are
going faster than C.
I designed a logic level convert circuit once that I spec'd with a
negative delay, at least until someone read it. I was *forced* to do
rise-times from 20-80 and delays from 50-50. The threshold wasn't at 50,
so until I showed the PHBs how stupid their requirements were, it had a
negative delay. ...and no, no electrons were hurt in testing the circuit.
--
Keith
|
Sorry; even measuring from the 5% point of a rising input pulse, to
any part (5%, 50% or 95%) of the output pulse, one will see some
positive delay - even over a distance of an inch long micristrip.
Light (or RF or pulses) travel about 11 inches in a nanosecond or
roughly 9 inches in a coax cable.
If one is using two probes so to simultaneously "see" both signals,
one must first determine what distortions in waveform(s) and in time
they present to the scope or other measuring device.
TTL logic roughly has a 7nSec rise and fall, and delay roughly of
15nSec.
For reasonably accurate measurements of all of those parameters, one
should have a system with an accuracy better than 1nSec and correctable
errors (time differences) that are also better than 1nSec.
For measuring delay in a one inch microstrip, those values should be
less than 100pSec and better be known values if that large; it helps
greatly to have a rather fast rise and/or fall in the pulse that is
going to be measured (100pSec or better - and the values also known). |
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Robert Baer
Guest
|
| Posted:
Sat Feb 05, 2005 8:10 pm Post subject:
Re: breaking the speed of light article on howstuffworks.com |
|
|
Gareth wrote:
| Quote: |
~~SciGirl~~ wrote:
As John Larkin said... "Same sort of thing, altering the shape of a
pulse and thinking that makes it go faster. Optically, an oscillatory
burst can appear to
exceed C if you sort of stand back and squint, but no photons are going
faster than C."
You can never be positive. If you cannot measure the position and
velocity of the photons simultaneously, how can you be sure they are
not going faster than c? Nobody can really measure the speed of the
particles as they exited the container, because you'd need to specify
the position defined as "exiting the container." This could disprove
the experiment, but it could also disprove the arguments of everyone
who does not believe the photons moved faster than c.
Einstein's theory of Special Relativity prevents anything with mass or
information from travelling faster than light. It is possible that one
day this theory will be proved wrong, but it has been validated by many
experiments over the last 100 years. The FAQ on Wang's webpage states
that his experiment does NOT contradict current theory, and cannot be
used to send information faster than light. See:
http://www.neci.nj.nec.com/homepages/lwan/faq.htm
For a very good demonstration of how light can appear to travel faster
than light have a look at the Java applet in the link below:
http://gregegan.customer.netspace.net.au/APPLETS/20/20.html
The Java applet also shows what happens if you try to send information
by modulating the beam.
There is some more information on superluminal phenomena here:
http://scienceworld.wolfram.com/physics/Superluminal.html
Gareth.
--
-----------------------------------------------------------------------
To reply to me directly:
Replace privacy.net with: totalise DOT co DOT uk and replace me with
gareth.harris
|
Yep! *SPECIAL* theory of Relativity.
Proven millions of times a day by many physicists the world around.
They get numbed by those facts.
However...
There is the theory of *GENERAL* relativity, where different frames
cannot be time-wise or speed-wise related ot each other. Case in point:
get a rocket starting from Earth, constantly accelerating away at some
value A, and at some point, its reference frame becomes inaccessible
from ours. No laws violated; just not practical to carry enough fuel to
accelerate so long that the velocity (before becoming inaccessible) gets
even near C.
An observer in that theoretical rocket would experience what all
physicists see: that the exhaust cannot get near C without using
gigantic amounts of energy.
But that has nothing to do with what an observer on Earth can measure
about the rocket itself, or what the passenger in the ship can measure
about the Earth.
By definition, the thought experiment sez that the velocity continues
to increase - and at some point the frames of reference disconnect.
Methinks the expanding universe can show us that limit, if we look.
What is it? the velocity of light. Gosh; how exact the *SPECIAL*
theory of relativity is! |
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Robert Baer
Guest
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| Posted:
Sat Feb 05, 2005 8:13 pm Post subject:
Re: breaking the speed of light article on howstuffworks.com |
|
|
Geodanah@yahoo.com wrote:
| Quote: |
~~SciGirl~~ wrote:
I just read that article and decided to find more information on
google
and found this group... I am 14 years old (yes, I do understand
quantum
physics, relativity, and some of the uncertainty principle; I'm
obsessed with science). After reading the article "How Time Travel
Will
Work" a few days ago, I was thinking and figured that the only thing
that would ever be able to travel beyond the speed of light without
being destroyed is light itself. Then today I read about that
experiment, and it supports what I thought. I do think it is possible
for light to travel faster than its own speed, and if this didn't
occur
in the cesium-filled container it could occur in space, if wormholes
exist. There also is a logical explanation for why the light appeared
to exit the container before it entered. I found it searching Google.
If you think about it enough, you realize there cannot be a set speed
that nothing can travel beyond
I suggest you look up Einstein's special theory of relativity. This is
not just "E=M(C squared)" (that is just the value of energy in matter,
and only at rest at that) it is the theory that explains why C is the
universal speed limit. Most of it can be understood without using
calculus if you find a decent book.
|
Meaning that those that use calculus are "indecent"? |
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Mark Jones
Guest
|
| Posted:
Sat Feb 05, 2005 8:55 pm Post subject:
Re: OT: breaking the speed of light article on howstuffworks |
|
|
John Larkin wrote:
| Quote: | On 4 Feb 2005 19:54:40 -0800, "~~SciGirl~~" <palmtree117@juno.com
wrote:
As John Larkin said... "Same sort of thing, altering the shape of a
pulse and thinking that makes it go faster. Optically, an oscillatory
burst can appear to
exceed C if you sort of stand back and squint, but no photons are going
faster than C."
You can never be positive. If you cannot measure the position and
velocity of the photons simultaneously, how can you be sure they are
not going faster than c? Nobody can really measure the speed of the
particles as they exited the container, because you'd need to specify
the position defined as "exiting the container."
You can build a fast shutter close to a source that only lets light
through for a nanosecond or less, and then measure arrival times some
distance away. Or do interferance experiments, which are exquisitely
sensitive to the speed of light. There are lots of techniques that
could detect ftl photons if they existed.
This could disprove
the experiment, but it could also disprove the arguments of everyone
who does not believe the photons moved faster than c.
Well, you can't disprove the conjecture that something, maybe a rogue
photon, does move ftl. But no experiment has ever demonstrated such,
and there's lots of theory that says it can't happen. The burden of
proof is to show a real case. "Laws" like the conservation of energy
get much of their force from the fact that no counter-case has ever
been observed.
You can observe a quasar flash that happened 8 billion years ago, on
the other side of this universe, and look at it in wavelengths from
radio through gamma rays; everything arrives at Earth at the same
time, which is pretty impressive.
John
|
It is compelling to believe that there could be some way to exceed C. On one
hand, it's great to be "pushing the envelope" by researching such things, but on
the other hand, don't let simple lust blind you into believing something is real
when it is not. Any theories are just heresay until proven otherwise. This
reminds me of a post I saw here recently which went something like this... (use
a monospaced font like Courier):
Scientists Discover New Waveform:
/-------------------------------\
| . |
| \\ |
| \ \ |
| _______) \______ |
| Time--> |
\-------------------------------/
The Sharktooth
Here's my two cents. Einstein's Time/Frame notion - and the notion that light
can travel faster than C with respect to other light - seems to be consistent
with observations made scientifically. i.e., measure the speed of light on two
opposing edges of an expanding universe from the center, and they have an
escaping velocity *delta* faster than C. But no light actually travels faster
than C in it's frame.
The other idea is that if string theory is correct, what if "FTL" is simply the
12th dimension? (I can't stand that vagueness about string theory - "if
something doesn't work right, just add another dimension...")
That said, also interesting the the propagation speed of EM radiation with
respect to C in various mediums. Research for instance, the speed of "c" in an
iron powder medium; the answer might surprise you.
-- "I think the state of the universe at the moment of conceptulization
determines part of how an entity further interacts with the rest of its reality,
and hence our experience with it." MCJ 200311 |
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Jim Thompson
Guest
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| Posted:
Sat Feb 05, 2005 9:42 pm Post subject:
Re: breaking the speed of light article on howstuffworks.com |
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|
On Sat, 5 Feb 2005 16:52:02 +0100, "Fred Bartoli"
<fred._canxxxel_this_bartoli@RemoveThatAlso_free.fr_AndThisToo> wrote:
[snip]
| Quote: |
For just parroting, without thinking, what you've read somewhere you've won
a Burridge award.
|
See! I told you! Burridge IS the standard ;-)
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food. |
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Fred Bartoli
Guest
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| Posted:
Sat Feb 05, 2005 9:42 pm Post subject:
Re: breaking the speed of light article on howstuffworks.com |
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|
"Robert Baer" <robertbaer@earthlink.net> a écrit dans le message de
news:4204CC6D.797AD960@earthlink.net...
| Quote: |
Bullshit.
It is clear that you do not understand what you thought you saw.
|
It is clear that you are more prompt to spout than to read carefully and
think.
I never claimed FTL propagation, but low phase shift on a _steady_ sine wave
signal in a low Z driven and unterminated TL.
And before you spout again, you'd better think and/or try before.
For a 115R 100mm PCB line (660nH,50p,2.2R per meter), about 5ns/m and
_fixed_ 100kHz frequency :
115R terminated : att = 0.02dB, phase = -18.5E-3 degree
unterminated : att = unmeasurable, phase = unmeasurable
At 10MHz the same line gives :
115R terminated : att = 0.02dB, phase = -2 degree
unterminated : att = 0.005dB, phase = -5E-3 degree
Now you can do the maths or setup a spice sim if you're lazy.
In case your still too lazy I've done your homework and the results closely
agree with the measurements.
At 100kHz the same line gives :
115R terminated : att = 0.024dB, phase = -20.8E-3 degree
unterminated : att = 17.5E-6dB, phase = 47.5E-6 degree (yes micro degree)
At 10MHz the same line gives :
115R terminated : att = 0.023dB, phase = -2.059 degree
unterminated : att = 5.65E-3dB, phase = -4.71E-3 degree
For just parroting, without thinking, what you've read somewhere you've won
a Burridge award.
--
Thanks,
Fred. |
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~~SciGirl~~
Guest
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| Posted:
Sat Feb 05, 2005 9:42 pm Post subject:
Re: breaking the speed of light article on howstuffworks.com |
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|
Ok, I found online somewhere that E = mc^2 has been revised to E =
mc2/mc^2 - 1. Is this true or is it just some bogus thing?
Also, say wormholes existed and you traveled through one. There would
be hyperspace around you, and so you would age quickly. Wouldn't you be
dead before you exited?
To whoever said calculus is easy... it's more than just rate of change,
isn't it? We learned that in Algebra 1! |
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~~SciGirl~~
Guest
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| Posted:
Sat Feb 05, 2005 9:42 pm Post subject:
Re: breaking the speed of light article on howstuffworks.com |
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Reply to...
"I suggest you look up Einstein's special theory of relativity. This is
not just "E=M(C squared)" (that is just the value of energy in matter,
and only at rest at that) it is the theory that explains why C is the
universal speed limit. Most of it can be understood without using
calculus if you find a decent book."
I have already learned that. E=mc^2 is only unification of mass and
energy. But, nothing I've read has described significant evidence that
there is proof nothing can cross the barrier. I understand special
relativity fine, it's modern relativity that really gives me trouble. |
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~~SciGirl~~
Guest
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| Posted:
Sat Feb 05, 2005 9:42 pm Post subject:
Re: breaking the speed of light article on howstuffworks.com |
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|
This is a question I have had since reading about Maxwell's
equations... in each one of them, there is this upside-down triangle
symbol that looks just like the delta triangle flipped over. What is
this symbol and what does it mean???
I took a quantum physics test on allthetests.com (to find it just type
"quantum" in the search box, there is only one) and I scored 8 out of
12. |
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