Speed of Dark ???

[Darryl Meister]

Your example demonstrates time dilation (specifically, the "twin paradox"). However, keep in mind that you can't actually travel "at" or beyond the speed of light, according to Einstein's equations. Also, light has a "speed" because it is a form of electromagnetic radiation (and this radiation travels at a constant velocity). Darkness, on the other hand, isn't anything, so it really can't have a speed.

The use of BobV in the cave is invaled as he did not travel the speed of dark.

While I was only joking about Bob, technically, since darkness has no speed, he was traveling at the "speed of darkness" while he was standing still. ;)

Even in a vacuum, there is pressure, a black hole contains gravity, and much of the like.

I would imagine that there are regions of space that would be considered perfect vacuums. Interestingly enough, black holes actually have quite a bit of stuff in them; it's just really, really compressed.

Does anyone have reccomendations for specific lens types or certain coatings for travelling at light speed?

I don't know. But I'm sure SOLA will make them. ;)

Best regards,
Darryl

[jofelk]

If we could travel faster than the speed of light then:


If you stood against a wall and then moved away from that wall at a speed faster than light, you would be able to see yourself standing against the wall for an instant.

The Hubble space telescope has now found a distant galaxy that formed after the big bang. I quote from the web site at:
http://hubblesite.org/newscenter/new.../2004/07/text/

"the NICMOS may have spotted galaxies that lived just 400 million years after the birth of the cosmos ".

We are able to look into the past!

[BobV]

I was called "lightning" in my early optical days.

Now, could it be that the speed of dark is -186,000mps, since for every action there is a reaction? Perhaps it's like some large reverse gear in the time/space scenario.

Bob V.

[paw]

I bet you guys are Star Trek fans!

[Steve Machol]

Here's a question for you all - What's the Speed of Gravity?

[Chris Ryser]

The speed of gravity is the same as that of light, say two physicists.

Knowing the speed of gravity is important for theories that attempt to unify the two pillars of physics: general relativity and quantum mechanics. The gravity measurement is not yet precise enough to rule any ideas in or out, but it confirms what most researchers had thought.

Einstein's theory of relativity only holds if the force of gravity acts at the same speed as light. Until now this was merely an assumption, says theoretical physicist Sergei Kopeikin of the University of Missouri in Columbia.

In 1999, Kopeikin extended Einstein's theory to explain how the gravitational fields of moving bodies distort radio waves and light. The speed of gravity can be calculated from measuring these effects.

The chance to take a reading came on 8 September last year. Jupiter passed in front of a distant quasar called J0842. Quasars are intense sources of radio waves that are thought to be giant black holes at the centres of galaxies.

Jupiter eclipses a quasar about once a decade. The planet's gravity bends the quasar's radio waves, shifting the quasar's apparent position in the sky.

If the speed of gravity were infinite, Kopeikin predicted that the quasar should have traced a perfect circle in the sky as Jupiter passed. If gravity had some finite speed, this circle would distort into an ellipse.

The distortion is tiny - equivalent to spotting a pin 250 miles away. To detect it, Kopeikin and his colleague Edward Fomalont of the US National Radio Astronomy Observatory in Charlottesville, Virginia, used a network of radio telescopes in the United States and Germany.

Groups of telescopes can function like a single huge instrument, through a technique called interferometry. By comparing the differences in the signals received at different places, the team pinpointed the quasar's position with incredible accuracy.

The shape of the quasar's motion gave a speed of gravity nearly identical to that of light, with an error margin of plus or minus 20%. "You can rule out a speed of gravity greater than twice the speed of light with a high degree of confidence," Fomalont told the American Astronomical Society's meeting in Seattle this week.

[Blake]

Dark is the absence of light, not the opposite of light. If light is the number 1, then dark is not -1, but 0. What we refer to as the speed of light is really the theoretical upper limit to the speed of light (light can be slowed down). Then the lower limit (an absolute zero speed of light) would be total darkness.


Blake

[Cowboy]

Blake,

That does make sense, however, that goes back to my "nothing" question. So, in hindsight, 0 is not total absence, only a theory. Example, If I have an apple in my hand and you take it, I have '0' in my hand, but the object still exists, only elsewhere. Try this, on your calculator, try deviding 0 by itself, the calculator will "error" as 0 cannot be proven to be 'nothing'. A mathematics professor taught me that. So, in conclusssion; we can only speculate that darkness has "0" speed, or that it is the displacement of light and travels at its reverse.

Chris,

Love the article, But I do have a question: How can you explain a blackhole? Its' gravity is so strong that light cannot escape. So in theory, would not gravity, given this scenario, be faster than light?

ED,

Laughed for a while with that one.

:cheers:

Cowboy

[jediron1]

Paw said:
Darkness is the absence of light the same way cold is the absence of heat.

That is true to a certain extent. If light travels at 186,000 (ruffly) miles per second, why can't darkness travel at the same speed?
My premise being if light travels away from a source and that source goes black has not the darkness traveled just as fast as the light to overtake the vacumn created by the absence of the light traveling away from the source at incredible speeds? If you
go into a dark room and turn on a light that room now becomes
illuminated by that light source. Now turn off the light and the room is just as fast turned to darkness. Now I know you will say
that is because there is an absence of light because where ever
light is darkness cannot be. That is true, but that does not take away from the fact that the darkness traveled just as fast as the light. If you have a black whole there is no light that they know of that excapes, but there is darkness that fills that void just quickly
as the light fills a void once it enters it. Just some ramblings!:bbg:

[Blake]

Saying you guys watch too much Star Trek would be for me like the pot calling the kettle black. However, I don't think you've quite grasped what I've been trying to say about dark being the absence of light, not some opposing force analogous to antimatter or antigravity.
Light is a form of energy. There is a finite amount of energy in the universe (law of conservation of energy). Think of the light as a train. When the train leaves the station, there isn't an "antitrain" that pulls up to take its place. There's just no train!
The speed of light is actually its velocity, the difference being that speed has a direction. If you reverse the direction of the light, it still has the same speed (well, assuming there was no acceleration/deceleration).
Anyway, I'm not a physicist so that's about the best I'm gonna be able to explain it.

Blake

[jediron1]

Blake said:
Dark is the absence of light, not the opposite of light. If light is the number 1, then dark is not -1, but 0. What we refer to as the speed of light is really the theoretical upper limit to the speed of light (light can be slowed down). Then the lower limit (an absolute zero speed of light) would be total darkness.

If you have read any papers on physics you will have noticed there are some people who think light is actully slowing down (light can be slowed down). If you had done some research you would have come up with some theories that say darkness is a property not just the absence of light even though that is one way.
:hammer:

[optispares]

Before the Big Bang, Darkness was Infinite

The Speed of Light is Finite

Step outside, look at the night sky, after a while, stars appear in places where one perceived only darkness. That's because infinitely faster darkness got to your eyes first, then the slowpoke known as "light" catches up at it's finite pace, and *finally* becomes visible.

[optispares]

but then again maybe not.

Physicists leveled heavy criticism Thursday on a report from last week that claimed the speed of gravity had been determined by observation and was equal to the speed of light.

One physicist called the interpretation of the finding "nonsense". Others were more diplomatic, suggesting that the experiment, involving observations of the bending of light from a distant galaxy as the light sped by the planet Jupiter, had instead measured other phenomena.

[jediron1]

The speed of light according to some is not finite. In an article in The Age.com it say's:
Australian scientists have discovered that light isn't quite as fast as it used to be. But it doesn't mean E=mc2 will be consigned to the dustbin, writes David Wroe.:bbg:

So as some theorized light maybe slowing down.

[Texas Ranger]

I believe that the light in the refrigerator is on all the time....

[GregG]

WOW!!!! I created quite a stir didnt i? so it seems i will never get an answer because it's not a valid question---or is it??? Nonetheles i will find that book and give it a read--never know i might actually learn something.Thanks for your replys.

No man can put a chain about the ankle of his fellow man without at last finding the other end fastened about his own neck

[Cowboy]

To all;

I find this to be quite fascinating. A group of individuals trying to prove each others point on the same subject but in different theoretical thinking. Just think about our philosophers of yesteryear, they to had to do the same, but they did not have the same technological gadgets that have allowed scientists in this field to write papers and prove theories to give us our own stepping stone to add to the subject.
When we speak of light and its speed, it reminds me of a documentary that I once saw: based on the reflection of a stars' light, infared meant that our universe was travleing toward it, and if it was ultraviolet, the opposite. Which means that the Univers is expanding in one direction and shrinking in the other. Yet, we can't determine if there is an end to the universe. The reason I mention it is becase we are infants in knowledge - all of us. The average human uses 9-12% of brain capacity, a genius uses only 15-18%. Until we can use 100%, we will constantly be learning. Based on the fact that we as a society have only just begun to see the possiblities of our universe and ourselves, it would be safe to say, that we do not have all the answers, we only have theory. We cannot prove that dark does not travel as fast, faster or at all over light.
If you reread all the posts, the serious inquiries, you will see that it all runs in a big circle, no one will be victorious. Personally, I think we should all shake hands and agree to accept and repect one anothers views and call it a day on this one.

:cheers:

Cowboy

[jofelk]

Cowboy said:

The average human uses 9-12% of brain capacity, a genius uses only 15-18%. Until we can use 100%, we will constantly be learning.

Sorry Cowboy but this is a myth. I think all of us on this board have shown this to be false! An easy read would be found at:
http://faculty.washington.edu/chudler/tenper.html

[edKENdance]

or this link 10% myth

[Cowboy]

Good follow-up with the article. Of course we use 100% of the neuro structure, what I was refering to was the idea that our intelligence level is still infant. We have not tapped into the ability to use the brain simotaneously. Envision this: Our brain works with electro impulses that stimulate functions. In essence, the brain is energy. Our body is carbon. The two coinside based on Functions of the brain alone. If 100% of the brain were to be used simotaneosly, there would be no need for the body (in theory) as the brain would become pure electro energy working from other electro impulses derived from other sources. Now, I know that your gonna come back and say that would be impossible, but how can we prove otherwise until we actually have use of the simotaneous 100%. We cannot simply exclude the idea or notion that this cannot be possible, that would be closed-minded.

:cheers:

Cowboy

[jediron1]

Texas that was funny about the refrigerator. Because every time I open the door the light is on and I can tell you I open the door a lot.:bbg: :D

[Pete Hanlin]

I think you are referring to Einstein's special theory of relativity with this line of reasoning. According to the special theory of relativity, time is "dilated" for someone moving near the speed of light.
Doesn't the Special Theory of Relativity also indicate that space is dilated for someone traveling approaching the speed of light? As I recall, Einstein crafted his theory using an old mathematical trick involving diminshing numbers (or something like that). As an object goes faster, time and space are effected.

Ah well, Einstein had nothing on Pete's Special Theory of Driving. According to that theory, if you are the fastest object on the roadway, your risk is diminished by half- after all, you only have to worry about things in front of you!

:D Have a specially relevant day!

[Darryl Meister]

Doesn't the Special Theory of Relativity also indicate that space is dilated for someone traveling approaching the speed of light?

Yeah, there's something called length contraction (from the person's perspective moving near the speed of light). Basically, since less time passes between two points for a person moving near the spped of light, the distance seems to be shorter ("contracted").

The basic equations in special relativity all involve a proportionality term:

SQRT(1 - v^2/c^2)

where v is the velocity and c is the speed of light. I've seen it derived on the basis of a "light clock" on a moving object using simple geometry. It actually looks surprising straightforward, if you can wrap your mind around the assumptions involved.

Note that when v is very small compared to c, which is generally the case since we don't usually travel anywhere close to the speed of light, the term essentially simplifies to 1, and all of your formulas look like your garden-variety, "classical mechanics" equations formulated by Newton.

Best regards,
Darryl

[jediron1]

Darryl Meister said:
Yeah, there's something called length contraction (from the person's perspective moving near the speed of light). Basically, since less time passes between two points for a person moving near the speed of light, the distance seems to be shorter ("contracted").

Not only the distance but time it self becomes realitive as you approach the speed of light. Time taken from Einstein's formula starts to slow down for an individual who is approaching the speed of light. The classic paradox is if you have twin brothers and take one and send him to our nearest star at the speed of light, when he returns he will be (if all other circumstances are equal) younger than his twin brother. Now the other paradox is we live in four diminsions ( height, width, length and time) with a hint from particle physics that it may be as high as 10 diminsions.
:D :bbg:

[Pete Hanlin]

Earlier someone (I think Steve) mentioned the speed of gravity. Although gravity is supposedly one of the "triplets" (electricity, magnetism, gravity), the funny thing about it is its relative weakness. The force of gravity is much lower proportionately speaking when compared to electricity and magnetism.

Also, regarding the 10 dimensions (which I've read about but won't pretend to really understand), I believe gravity is the key to the additional dimensions (as I recall). Basically, gravity is the only thing that can escape the dimensions to which we are accustomed.