PDA

View Full Version : Warp Theory



brianok
2001-Oct-25, 02:10 PM
Here is a neat site for a little lesson on warp technology:


http://www.sun-sentinel.com/graphics/science/warp.htm

Mr. Wree
2001-Oct-27, 05:37 PM
The link doesn't quite tell the whole story about warp physics, not that I know it myself.

The interior volume of the warp bubble -- what is refered to as subspace -- is the fifth dimension, and while in subspace the spacecraft never actually travels at, or faster than, the speed of light (which would be a violation of Special Relativity).

It is because the distance through subspace between the spacecraft's place of origin (where the warp drive was engaged, causing the spacecraft to leave normal space) and its destination (where the warp drive is disengaged, causing the spacecraft to return to normal space) is shorter than the corresponding distance across normal space that the travel time for the entire trip is shorter, as if the spacecraft had traveled through normal space faster than the speed of light.

Presumably, the four normal dimensions are folded around the fifth dimension and travel through the fifth dimension is like traveling the chord of a circle or sphere -- a shorter distance than traveling around the cicurmference.

ljbrs
2001-Oct-27, 11:13 PM
brianok:

Do not show URLs which prevent escape (except by leaving the internet completely and re-entering).

This subject (superluminal) does not belong here but belongs in the topic *Against the Mainstream*, because warp drive only exists in the minds of science-fiction writers and in the minds of their readers/audience.

Nothing goes faster than light speed (even light itself). *Superluminal* motion is only an illusion from the point of view of the observer. The light (or object) is not going faster than the speed of light, but only appears to be doing so, because of the angle by which it is viewed.

Nothing with mass goes as fast as the speed of light. Scientists have not yet been able to break that speed (except in experiments where the appearance of faster-than-light travel by photons themselves is only a trick -- an illusion -- by the experimenter).

Warp speed does not exist in science -- only in science fiction.

ljbrs /phpBB/images/smiles/icon_mad.gif

<font size=-1>[ This Message was edited by: ljbrs on 2001-10-27 19:16 ]</font>

Mr. Wree
2001-Oct-28, 01:30 AM
<<...Do not show URLs which prevent escape (except by leaving the internet completely and re-entering)...>>

The link opened another window for me, easily closed when I was finished.

<<...This subject (superluminal) does not belong here but belongs in the topic *Against the Mainstream*,..>>

Then the moderator(s) will move it, without the necessity of you editorializing -- unless you think them not up to their task?

Mr. X
2001-Oct-28, 02:54 PM
Do not show URLs which prevent escape (except by leaving the internet completely and re-entering).


Um? Right. It's always possible to leave a url.

Oh my god. You didn't notice it opened in a new window? That's why maybe the back button didn't work? That all you had to do was close the newly opened window?

<font size=30 color=red>LOL</font>

Maybe that's why people with cable modems die on their keyboards attempting to escape the URL. They can't disconnect! (Actually they/I can.)

<font size=-1>[ This Message was edited by: Mr. X on 2001-10-28 09:56 ]</font>

Phobos
2001-Oct-29, 10:45 AM
On 2001-10-27 19:13, ljbrs wrote:
brianok:

...

This subject (superluminal) does not belong here but belongs in the topic *Against the Mainstream*, because warp drive only exists in the minds of science-fiction writers and in the minds of their readers/audience.

Nothing goes faster than light speed (even light itself). *Superluminal* motion is only an illusion from the point of view of the observer. The light (or object) is not going faster than the speed of light, but only appears to be doing so, because of the angle by which it is viewed.

...

ljbrs /phpBB/images/smiles/icon_mad.gif

Are you sure ?

What about this ? (http://news.bbc.co.uk/hi/english/sci/tech/newsid_841000/841690.stm)

and this, (http://www.stsci.edu/ftp/science/m87/m87.html)

and this ? (http://www.aip.org/enews/physnews/1998/split/pnu398-2.htm)

There are other examples.

Jeff

ToSeek
2001-Oct-29, 03:55 PM
My understanding of the recent "superluminal" experiments is that they use tricks involving interference among light of various wavelengths to get the combined wavefront to move through a medium faster than the speed of light. No actual photons are moving faster than light.

DStahl
2001-Oct-29, 09:35 PM
Mr. X, in re your comment replying to ljbrs: People may be using a variety of browsers on Linux, Mac, or Windows. Please don't assume that someone is not very bright because a particular website is or is not browser-friendly on their system. For myself, I am viewing this right now in a rather kludgy browser I wrote using VB because I became disgusted with the feature bloat of Netscape and Internet Explorer. I'll bet an internet cookie you can't predict how my little program will react to a javascripted web page, eh? (Now if I could just squash all the bugs in it...!)

Anyway, I imagine that you were just doing a bit of gentle teasing--but it could have been taken rather harshly, in my opinion. Hey, be sure to let us know if and when you build that lifter!

Addendum: As currently configured, the new BABB software seems to always open a link in a new window. That's a pain for me because my kludged program does not handle that gracefully. Here's a workaround:

Don't click on a link with the left mouse button, right-click it instead. Many browsers will pop up a menu, and one of the items on the menu should be something like Copy Shortcut or Copy Link Location. Choose that option, and then paste the link into the address text box at the top of your browser window. (In Windows you can just highlight the entire text box and then press Ctrl-v to paste from the Windows clipboard.) Then click Load or hit return or whatever it takes to get your particular browser to load the page.

I have yet to get Linux to communicate with my modem, so I can't offer any advice to those of you running a penguin box. But I'll bet you don't need my advice anyway, you smarties you. *grin*

<font size=-1>[ This Message was edited by: DStahl on 2001-10-29 16:58 ]</font>

Russ
2001-Oct-30, 12:19 AM
On 2001-10-27 13:37, Mr. Wree wrote:
The link doesn't quite tell the whole story about warp physics, not that I know it myself.

The interior volume of the warp bubble -- what is refered to as subspace -- is the fifth dimension, and while in subspace the spacecraft never actually travels at, or faster than, the speed of light (which would be a violation of Special Relativity).

It is because the distance through subspace between the spacecraft's place of origin (where the warp drive was engaged, causing the spacecraft to leave normal space) and its destination (where the warp drive is disengaged, causing the spacecraft to return to normal space) is shorter than the corresponding distance across normal space that the travel time for the entire trip is shorter, as if the spacecraft had traveled through normal space faster than the speed of light.

Presumably, the four normal dimensions are folded around the fifth dimension and travel through the fifth dimension is like traveling the chord of a circle or sphere -- a shorter distance than traveling around the cicurmference.




As I understand warp theory, the warp bubble puts the ship in "subspace" and it nolonger has any mass in "realspace". This allows the ship to move at "C". They then create another warpbubble that surounds the first and deflect the first in such a way that the ship moves in the desired direction WRT the second warpbubble. They then allow the first bubble to colapse and start the process again. The faster they generate and deflect the bubbles, the higher the warp factor.

I have the "Star Trek Technical Manuals" and that's what I get out of them. Don't necessarilly mean I done went and got it rite tho.

Mr. X
2001-Oct-30, 01:42 AM
On 2001-10-29 16:35, DStahl wrote:
Mr. X, in re your comment replying to ljbrs: People may be using a variety of browsers on Linux, Mac, or Windows. Please don't assume that someone is not very bright because a particular website is or is not browser-friendly on their system. For myself, I am viewing this right now in a rather kludgy browser I wrote using VB because I became disgusted with the feature bloat of Netscape and Internet Explorer. I'll bet an internet cookie you can't predict how my little program will react to a javascripted web page, eh? (Now if I could just squash all the bugs in it...!)

Anyway, I imagine that you were just doing a bit of gentle teasing--but it could have been taken rather harshly, in my opinion. Hey, be sure to let us know if and when you build that lifter!

Addendum: As currently configured, the new BABB software seems to always open a link in a new window. That's a pain for me because my kludged program does not handle that gracefully. Here's a workaround:

Don't click on a link with the left mouse button, right-click it instead. Many browsers will pop up a menu, and one of the items on the menu should be something like Copy Shortcut or Copy Link Location. Choose that option, and then paste the link into the address text box at the top of your browser window. (In Windows you can just highlight the entire text box and then press Ctrl-v to paste from the Windows clipboard.) Then click Load or hit return or whatever it takes to get your particular browser to load the page.

I have yet to get Linux to communicate with my modem, so I can't offer any advice to those of you running a penguin box. But I'll bet you don't need my advice anyway, you smarties you. *grin*


All right, I apologize to lqjbrs (weird name).

I am building the lifter, see the new flight propulsion test thread.

And watch out between those dial-up modems and linux, they can be allergic to one another!

Ring
2001-Oct-30, 01:48 AM
On 2001-10-27 19:13, ljbrs wrote:
brianok:

Do not show URLs which prevent escape (except by leaving the internet completely and re-entering).

This subject (superluminal) does not belong here but belongs in the topic *Against the Mainstream*, because warp drive only exists in the minds of science-fiction writers and in the minds of their readers/audience.

Nothing goes faster than light speed (even light itself). *Superluminal* motion is only an illusion from the point of view of the observer. The light (or object) is not going faster than the speed of light, but only appears to be doing so, because of the angle by which it is viewed.

Nothing with mass goes as fast as the speed of light. Scientists have not yet been able to break that speed (except in experiments where the appearance of faster-than-light travel by photons themselves is only a trick -- an illusion -- by the experimenter).

Warp speed does not exist in science -- only in science fiction.

ljbrs /phpBB/images/smiles/icon_mad.gif

<font size=-1>[ This Message was edited by: ljbrs on 2001-10-27 19:16 ]</font>


The Alcubierre Warp Drive is not science fiction. It's fully within the scope of Einstein's Field equations. The only problems are that it requires exotic matter and infinite energy.

http://www.npl.washington.edu/AV/altvw81.html

<font size=-1>[ This Message was edited by: Ring on 2001-10-29 20:50 ]</font>

<font size=-1>[ This Message was edited by: Ring on 2001-10-29 20:52 ]</font>

Mr. X
2001-Oct-30, 10:21 AM
On 2001-10-29 20:48, Ring wrote:
The only problems are that it requires exotic matter and infinite energy


Well then the matter is almost solved as it requires "only" that /phpBB/images/smiles/icon_razz.gif

Kaptain K
2001-Oct-30, 11:40 AM
The Alcubierre Warp Drive is not science fiction. It's fully within the scope of Einstein's Field equations. The only problems are that it requires exotic matter and infinite energy.

Hate to be a party pooper /phpBB/images/smiles/icon_frown.gif but exotic matter is, at this time, science fiction. As for infinite energy, I believe that falls under the heading of fantasy.

_________________
All else (is never) being equal.

<font size=-1>[ This Message was edited by: Kaptain K on 2001-10-30 06:41 ]</font>

GrapesOfWrath
2001-Oct-30, 12:01 PM
Perhaps he meant that it was science fantasy instead of science fiction?

Ring
2001-Oct-30, 03:18 PM
I think you're missing my point. I'm not saying that a warp drive is possible, I'm just saying that neither GR nor SR prohibits it. Keep in mind that none of the accepted possibilities involve, *locally*, faster than c motion. Plus, the Casimir effect can already produce the effects of exotic matter.

All I'm really saying is that there are some very eminent scientists working on this stuff and therefore I don't think it should be considered to be purely "Science Fiction"

Do I think it's going to happen in my lifetime? Absolutely not!

BTW, it's nice to see that first time posters on this board are welcomed with such polite sarcasm. You should be ashamed of yourselves. /phpBB/images/smiles/icon_smile.gif

http://www.grc.nasa.gov/WWW/PAO/html/warp/warpstat.htm



<font size=-1>[ This Message was edited by: Ring on 2001-10-30 10:19 ]</font>

Valiant Dancer
2001-Oct-30, 04:00 PM
On 2001-10-27 13:37, Mr. Wree wrote:
The link doesn't quite tell the whole story about warp physics, not that I know it myself.

The interior volume of the warp bubble -- what is refered to as subspace -- is the fifth dimension, and while in subspace the spacecraft never actually travels at, or faster than, the speed of light (which would be a violation of Special Relativity).

It is because the distance through subspace between the spacecraft's place of origin (where the warp drive was engaged, causing the spacecraft to leave normal space) and its destination (where the warp drive is disengaged, causing the spacecraft to return to normal space) is shorter than the corresponding distance across normal space that the travel time for the entire trip is shorter, as if the spacecraft had traveled through normal space faster than the speed of light.

Presumably, the four normal dimensions are folded around the fifth dimension and travel through the fifth dimension is like traveling the chord of a circle or sphere -- a shorter distance than traveling around the cicurmference.




Far be it from me to pass up a good Star Trek reference. Here is a page describing Warp drives in Star Trek.

http://www.ditl.org/scitech/hedwarp.htm

Mr. X
2001-Oct-30, 08:44 PM
Do I think it's going to happen in my lifetime? Absolutely not!

Well, talk about being pessimistic! It's not going to happen in your lifetime with THAT attitude, that's for sure! /phpBB/images/smiles/icon_lol.gif

Don't ruin it for the rest of us! /phpBB/images/smiles/icon_biggrin.gif

ljbrs
2001-Nov-25, 08:18 PM
Wree:

Instead, from now on, I will ignore URLs. The problem is solved...

/phpBB/images/smiles/icon_wink.gif /phpBB/images/smiles/icon_wink.gif /phpBB/images/smiles/icon_wink.gif

ljbrs

<font size=-1>[ This Message was edited by: ljbrs on 2001-11-25 15:21 ]</font>

The Bad Astronomer
2001-Nov-25, 08:25 PM
On 2001-10-27 21:30, Mr. Wree wrote:
Then the moderator(s) will move it, without the necessity of you editorializing -- unless you think them not up to their task?


The only mod is me, and I am too busy to keep track of every thread. In this case, ljbrs is correct, so I am moving this to Against the Mainstream. For the time being, warp drive theories belong there.

Chip
2001-Dec-06, 06:13 AM
Well, I think if warp speed ever were to exist in "real life," it would have to exist without negating those aspects of physics that prevent mass traveling at the speed of light. How could that be?

There have been some hypothesis (not even close to a theory) wherein matter is enclosed somehow in a shell of negative energy, that is somehow contained and maintained. The hypothetical spaceship moves through space within this shell or "bubble" at considerably less speed than the speed of light. The negative energy bubble somehow by it's nature slips through space at the speed of light. (It still takes 4 years for it to get to Alpha Centauri, but that's a lot less than 10,000 years at a very fast sub-light speed!)

There was an analogy about this: A ladybug walking on a bedsheet. The bug is "matter" and the sheet is "light." The bug travels at a set speed but the sheet it's on is also pulled along at it's set "speed" relative to the bug, and both are moving relative to the rest of the bedroom, i.e. "the universe."

"Warping" space implies bending the "fabric" of space allowing a shorter distance for the spaceship than what would appear from an observer outside the ship.

I think that if all that were somehow perfected, the crew would not be happily walking about and talking around the ship like the folks on Star Trek. I think it would be somewhat akin to Forbidden Planet, where they'd have to climb into some special chambers and be partially held in transit in an energy/matter flux state. Emerging with a headache just before touchdown.

Presently, sending radio signals that contain translatable instructions for building computers wherein the signal's telemetry is also an interactive downloadable program, seems like the first way to contact "them" out there. This is much more technologically feasible than warp drive at present, though nobody has done it yet - to my knowledge.

Chip

"Why haven't I've seen this all along?!" - Dr. Morbius from Forbidden Planet


<font size=-1>[ This Message was edited by: Chip on 2001-12-06 01:24 ]</font>

dgavin
2001-Dec-07, 02:28 AM
Warpdrive...

Actually there are quite a few theories out there how to achive faster then light speeds. Some which work within the -theory- of relativity, some that don't.

Nasa itself has moved a project out of theroretical, into conseptual modeling of a Gravity Drive. Very much akin to Ambercombe's Warp Theory, except this uses limited energy, to create a limited gravitational warping of space, compressing space infront of the ship, and expanding it behind the ship. The effect would be akin to surfing the crest of a tsunami when people thought the sound barrier couldn't be broken, even though most tsunami's did. Considering Nasa has already produced gravity altering devices, and antimater containment units, this is probably the most likely method that will achive faster then light speeds. Considering it went from theroetical to conceptual design 1.5 years ago by Nasa, I'd guess it's likely there will be a prototype in 20 to 30 years.

Dimensional Drive (SubSpace, whatever).
Somehow a ship is moved into a different dimension, and moves through that, reducing travel time. Considering that Quantum mechanics only hint's at other dimensions, and there is no real proof of them, This type of drive would be unlikely, but may be a possibility. Maybe Gene Roddenberry had soemthing here, and maybe not.

Quantum Matter Accelaration drive.
Read about this one about a year ago. Basically to sum it up, it used a quantum wave effect to thrust matter/energy out of an engine at speeds greater then light, allowing a ship to reach, perhaps exceed the speed of light. Major problem is that even a single partical of matter slamming into a ship moving at even 1/2 light speed would demolish it.

Hyperdrive, (Wormhole Drive)
Probably the oldest faster then light drive theory on the books. Basically rips a long stable a hole through space, then travels through it. Problem with this one is there no way of knowing whats on other side (first timr you go someplace) once you stop the drive. As Han Solo said, "We could bounce through a black hole or into a Super Nova, and that would end this little trip right fast." This type of drive is really the stuff of Sci Fi.

Blink Drive (Probibility Drive)
Alhough only the realm of sci-fi, got to admire this one, as some do theorize about it. Instentatously moves the ship from one point in space time to another, by altering reality itself via some application of probibility mechanics. Don't ask for more of an explanation, and personally, -I don't think so-.

Now for the wildest, and my favorite for "Out there" theroies.

Quantum Reflux Generator
Uses an mixture of nuclear physics at the Quantum level to produce a drive that exponetialy keeps increasing it's thrust. I can't even remember the details behind this one, much less understand the math. It's drawbacks are also manifold. One, there is no way to -stop- the Quantum reaction, short of seperating the ship from the engine, then blowing up the engine. Two, suffers the same problem with dust as the Quantum Matter Accelaration drive, but at an exponetial level. I think someone was definately dreaming on this one...it should be called the Kamakasi Drive perhaps?

Space Fold drive.
Another of the almost instentaeous drives. It folds space like a sheet paper in half, then moves, not along the space fold, but jumps across the shortened gap. (IE Event Horizon movie based on this one). Problems... Ok fist how much enery does it take to fold space that much, and next, how do you fold it at the half way point, if your not there yet? Another one thats -Out there-

Speed of Thought drive
Uses psionic applification of latent psionic powers to either effect movement outside of space/time, or intenateous teleportation of the ship. (See 'The Rowan' for Sci Fi example) Problems? well, no proof that ESP even exists. Infact most profesional parapsychologists (I'm talking researchers, not Miss Cleo) feel that ESP may actually be latent insticts at work.

Anyway hope you enjoy these theroies. Even though one isn't a theory anymore.

I also read up about NEC getting light in effect, to move faster through some medium, and laughed at the end.

"Of course this method cannot be used to send information at faster then light speeds."

Oh really? ever think of turning the laser on and off at intervuls? Wow what a novel idea... You just broke relativity why not try shooting a pattern through it intead of just guessing....

I'm not conviced they truley did what they said. But if they had, then they could use on/off pulses through the medium, if not light wave modulation. Thier closing statement convinced me they are probably "Out there" and maybe a little "Full of it". Either way, it's silly that they didn't even try to send on/off pulses.

I'll put my stock in Nasa, which has managed to produce Anti-Matter containment, Ion Propultion, and Gravity Altering devices 50 to 100 years before science thinks they are possible.

Doodler
2002-Sep-13, 10:18 PM
I have a minor issue with lightspeed being an "unreachable" velocity. Last time I checked, even minute acceleration can overcome any velocity, given time. Now how is it that this one velocity breaks all the rules? Granted the speed of light defines the rate at which we perceive the universe, but how is it we are bound never to break it? Given time and advancing technology (which these days, seems to be advancing at breakneck speed) why would it not be possible that one day someone could accelerate sufficiently to overcome the light barrier? I seem to remember reading of similar debates over the sound barrier. How is this different? What's the catch?

Kaptain K
2002-Sep-14, 11:19 AM
Doodler,
The answer lies in what is known as "relativistic mass". As the velocity increases, the resistance to acceleration increases. As the velocity approaches "c", the resistance approaches infinite. Given a non-zero rest mass, it would take infinite time to reach the speed of light for any rate of acceleration.

Avatar28
2002-Sep-14, 01:46 PM
I've seen one other theory that I personally like for high speed, possibly superluminal speeds.

Zero Point drive. Basically the theory says that if Zero Point Energy is responsible for inertia then if you can learn to control the ZPE it may be possible to reduce the effective mass and resistance to acceleration. Potentially it might even allow you to go superluminal, though who knows what would happen if you did.

traztx
2002-Sep-14, 04:45 PM
On 2001-12-06 21:28, dgavin wrote:
Warpdrive...

Blink Drive (Probibility Drive)
Alhough only the realm of sci-fi, got to admire this one, as some do theorize about it. Instentatously moves the ship from one point in space time to another, by altering reality itself via some application of probibility mechanics. Don't ask for more of an explanation, and personally, -I don't think so-.


And don't forget powering the ship on bistromatics. I would show you my starship, but I left the SEP field on and can't seem to find it...

Chuck
2002-Sep-15, 12:02 AM
The PseudoWarp Drive

Fly a ship to Alpha Centauri and back at near light speed. The occupants age a week. Put everyone on earth into cryonic suspension and revive them a week before the ship returns. Everyone ages one week giving the effect of faster than light travel. It's all relative anyway.

Mainframes
2002-Sep-15, 03:28 PM
On 2002-09-13 18:18, Doodler wrote:
I seem to remember reading of similar debates over the sound barrier. How is this different? What's the catch?


I think the problem with breaking the sound barrier was finding a material that didnt melt (amongst other properties required for an aircraft), when approaching the speed of sound.

As mentioned above, the speed of light is more of a breaking the laws of physics problem.

M

DaveC
2002-Sep-16, 03:50 PM
At 700 mph, I don't think melting was an issue. The key to breaking the sound barrier was designing an airframe than would witstand the shock of breaking through a pressure front.

WWII V2 rockets exceeded the speed of sound and were made of essentially the same materials as airplanes of the day, but because they didn't rely on aerodynamic lift to fly, they didn't face the same problems in loss of stability as they broke through the sound barrier. It was wing design that was the main challenge for supersonic airplanes - making sure the angle of the leading edge of the wing was the same as the angle of the shock wave so the wing wasn't subjected to a shearing stress as it passed through.

Avatar28
2002-Sep-16, 05:30 PM
On 2002-09-16 11:50, DaveC wrote:
At 700 mph, I don't think melting was an issue. The key to breaking the sound barrier was designing an airframe than would witstand the shock of breaking through a pressure front.

WWII V2 rockets exceeded the speed of sound and were made of essentially the same materials as airplanes of the day, but because they didn't rely on aerodynamic lift to fly, they didn't face the same problems in loss of stability as they broke through the sound barrier. It was wing design that was the main challenge for supersonic airplanes - making sure the angle of the leading edge of the wing was the same as the angle of the shock wave so the wing wasn't subjected to a shearing stress as it passed through.


Actually, the X-1, like all planes of the day, had straight wings. That was the problem, the shockwave would cross the wings and cause the airplane to shake itself apart.

DaveC
2002-Sep-16, 06:30 PM
Right. The X-1 taught us a lot about how not to build a supersonic aircraft.

Doodler
2002-Sep-19, 01:50 PM
To Kaptain, has anybody ever touched on what causes this resistance? In the (relatively) empty vacuum of interstellar space, what is there to resist against? What is it about trans-light speeds (note: I use that term in the same sense that trans-sonic speeds are those around Mach .85+) that changes the rules of physics? Sorry if it seems like I have a million questions, but something about this doesn't seem right. An object gaining resistance would need something resisting against it, what is the source of this resistance? (Last question, I promise /phpBB/images/smiles/icon_smile.gif )

Kaptain K
2002-Sep-21, 07:11 PM
On 2002-09-19 09:50, Doodler wrote:
To Kaptain, has anybody ever touched on what causes this resistance? In the (relatively) empty vacuum of interstellar space, what is there to resist against? What is it about trans-light speeds (note: I use that term in the same sense that trans-sonic speeds are those around Mach .85+) that changes the rules of physics? Sorry if it seems like I have a million questions, but something about this doesn't seem right. An object gaining resistance would need something resisting against it, what is the source of this resistance? (Last question, I promise /phpBB/images/smiles/icon_smile.gif )

OK, lets try this again.

F=ma => a=F/m
As long as mass and force remain constant, the acceleration remains constant.
In relativity, "mass" (resistance to change in velocity) is a variable.
If:
m(sub)r is relativistic mass
m(sub)0 is rest mass
v is velocity
and
c is speed of light
then
m(sub)r=m(sub)0/(1-v^2/c^2)
For low speeds (i.e. the world we are used to), v^2/c^2 is near enough to zero that it can be considered to be zero and m(sub)r=m(sub)0.
But, as v approaches c, the term (1-v^2/c^2) approaches zero and m(sub)r approaches infinity. So, as v increases toward c, a given amount of force results in a smaller amount of acceleration.

David Hall
2002-Sep-21, 07:56 PM
On 2002-09-19 09:50, Doodler wrote:

To Kaptain, has anybody ever touched on what causes this resistance? In the (relatively) empty vacuum of interstellar space, what is there to resist against? What is it about trans-light speeds (note: I use that term in the same sense that trans-sonic speeds are those around Mach .85+) that changes the rules of physics? Sorry if it seems like I have a million questions, but something about this doesn't seem right. An object gaining resistance would need something resisting against it, what is the source of this resistance? (Last question, I promise /phpBB/images/smiles/icon_smile.gif )


Let's see if we can make this simpler. You are making a false analogy between the sound barrier and the light barrier.

The sound barrier is a pressure wall. It is a function of wind resistance. All it really takes to get beyond it is enough force to break through the wall. Of course, if your vehicle isn't designed for such forces it'll fall apart, but it can still break through. There are no fundamental reasons why you can't go that fast.

Light speed, or more accurately "c", however is not a function of outside resistance. It is a fundamental property of the universe, and therefore intrinsic to the moving object itself. There is a logarithmic (?) scale of energy versus acceleration. The faster you are moving, the greater the additional energy needed to make you go faster. You aren't pushing against anything, you are just becoming more difficult to move yourself.

As you gain speed, it's as if your body is also gaining mass (that's a simplistic way to put it though). As you near the speed of light, you get "heavier and heavier", so to speak, and the additional energy required to push you faster reaches up to infinity. There is no "barrier" to break through; you just can't muster enough energy to go faster.

There are other effects as well, such as time dilation, but I'm not going to go into those. And as I understand it, you aren't really gaining mass, but the effect comes out equivalent to that in the math. Just suffice it to say that there isn't enough energy in the universe to make even the smallest of masses reach c.

I hope this makes it clearer.

Doodler
2002-Sep-24, 12:07 AM
I follow your reasoning though I do not entirely understand why. An object in a vacuum should continue to accelerate equal to the amount of thrust applied, regardless of velocity, because the reaction mass being expelled should continue to apply thrust to an object with equal power as the reaction mass's initial velocity relative to the object it is interacting with is zero. The reaction mass's energy is released from relative rest in whichever direction you are applying thrust as if the object is not in motion, should it therefore be acting against only the mass of the object at relative rest, not at its velocity relative to its departure point. Take Deep Space 1 as an example, it continuously applied thrust for over a hundred days solid. By your reasoning, it should have been forced to increase its thrust along the same curve as its relative acceleration. Its mass would increase, however minisculy, as it gained velocity, which it did rather impressively. Did this occur in any measurable extent during those extended burns? Or is this an issue that would not be measurable until relativistic speeds are a factor?

Wyvern
2002-Sep-24, 03:41 AM
On 2002-09-23 20:07, Doodler wrote:
I follow your reasoning though I do not entirely understand why. An object in a vacuum should continue to accelerate equal to the amount of thrust applied, regardless of velocity, because the reaction mass being expelled should continue to apply thrust to an object with equal power as the reaction mass's initial velocity relative to the object it is interacting with is zero. The reaction mass's energy is released from relative rest in whichever direction you are applying thrust as if the object is not in motion, should it therefore be acting against only the mass of the object at relative rest, not at its velocity relative to its departure point. Take Deep Space 1 as an example, it continuously applied thrust for over a hundred days solid. By your reasoning, it should have been forced to increase its thrust along the same curve as its relative acceleration. Its mass would increase, however minisculy, as it gained velocity, which it did rather impressively. Did this occur in any measurable extent during those extended burns? Or is this an issue that would not be measurable until relativistic speeds are a factor?


It all depends on your frame of reference. Perhaps the best way to describe relativity is the famous flashlight analogy. Let's say you are moving at a significant percentage (let's say 90%) of the speed of light and you hold a flashlight. Meanwhile, you pass an observer on a space station who is "stationary". When you turn on the flashlight, you see the beam move away from you at the speed of light. At the same time, the stationary observer also sees the beam move away at the speed of light. In 1 second, the beam of light in both reference frames moves 300,000 km, and yet the stationary observer sees you move away at 90% of that speed, moving 270,000 km in that second. Newtonian mechanics says that in the same time, the beam in your reference frame should have moved 30,000 km in one second, and yet you observe it move 300,000 km. In other words, time is not constant. Time has slowed down in your reference frame when compared to the "stationary" reference frame.

Now, extend this to attempting to approach the speed of light. As you approach the speed of light, time seems to slow when observed from an outside reference frame. This time dialation is the same effect that seems to increase your mass which is what prevents you from exceeding the speed of light in any external reference frame.

Incidentally, I believe the mass effect is very real from an external vantage point - please correct me if I'm wrong, but I seem to remember that matter moving at a significant percentage (i.e. 99.999+%) of c will actually cause a black hole to form behind it. It's been awhile since I really got into relativistic physics.

beskeptical
2002-Sep-24, 08:23 AM
I'm chiming in late so forgive the untimely response to a matter that has been resolved.

ljbrs wrote on 2001-10-27 19:16: Do not show URLs which prevent escape (except by leaving the internet completely and re-entering).

This subject (superluminal) does not belong here but belongs in the topic *Against the Mainstream*, because warp drive only exists in the minds of science-fiction writers and in the minds of their readers/audience.


As a less than competent chatter, I don't even know what, "Do not show URLs", means. However, I understand what the message meant.

The comments were useful but the poster's frustration was apparent. From a sometimes outwardly frustrated person, (me), to another, I assume you were having a bad computer day, and I for one understand.

To Mr. X, I think you meant to defend the original poster as much as to be sarcastic to ljbrs. So I also understand.

Mr. Wree was a bit more polite and I assume might not have said anything if ljbrs had had a nicer tone. I understand this as well.

So why am I writing this when I really shouldn't be butting in, and, most of us know we really should be nice? Because I would want understanding if I have a bad computer day. And, because I would want understanding if I react in a sarcastic or condescending way to something posted.

Its a girl thing. /phpBB/images/smiles/icon_smile.gif /phpBB/images/smiles/icon_smile.gif /phpBB/images/smiles/icon_smile.gif /phpBB/images/smiles/icon_smile.gif

As to the warp theory, I had read about it in a book, Hyperspace, by Michio Kaku, 1994. He mentioned Star Trek's use of the term. I was impressed that Star Trek actually had at least some tie to reality with warp drive. I had never realized that before reading the book.

And, the idea allows me to contemplate humans finding a way conquer the distance barrier in space travel. Warp speed itself doesn't have to work, but its a way to see the light speed barrier's potential to be overcome. IE, it's much more realistic to think there might be a means that we haven't found yet to travel to other stars.

_________________
Evolution is just a theory. Better fasten your seatbelt, so is gravity.
Beskeptigal.

PS, just I trick I learned which you regular computer folks don't need, but I have found very useful:

I click on to 'reply with quote' to see how someone coded something. So, if for example I wanted to see how to make giant red letters, I could open the post with the big red letters and the code would be revealed.

<font size=-1>[ This Message was edited by: beskeptical on 2002-09-24 04:32 ]</font>

Kaptain K
2002-Sep-24, 05:08 PM
I follow your reasoning though I do not entirely understand why. An object in a vacuum should continue to accelerate equal to the amount of thrust applied, regardless of velocity, because the reaction mass being expelled should continue to apply thrust to an object with equal power as the reaction mass's initial velocity relative to the object it is interacting with is zero.
Doodler,
I think that the point you are missing is the difference in frame of reference. To an outside observer, the rate of acceleration decreases with increased velocity, due to increased relativistic mass. To the accelerating observer, acceleration remains constant, due to time dilation.
Thought experiment:
You are on a rocket that is capable of constant, continuous one "g" thrust. To those of us on Earth, your rate of acceleration will decrease as you approach "c". To us, you will never reach "c", no matter how long you keep the rocket blasting. To you however, it will appear that you are constantly accelerating at one "g". After a month, you will be about 20 light years away from Earth. If you now reverse course and decelerate for a month, you will be 40 light years out. Accelerate back toward Earth for a month, decelerate for a month and you will be back home, four months older, but 80 years will have passed here.

Doodler
2002-Oct-10, 07:57 PM
Hiya Kaptain, sorry this response has been so long in coming, I really put some thought into your last post and I see from it where we differ. My personal belief is that the so-called slowing of my acceleration as seen from Earth is an optical illusion, time is, as I believe it, continuing in synch in both frames. The illusion, as the Earth frame perceives my ship, is that the light being reflected back is being distorted because of the outward motion of my vessel. e.g. as my vessel reaches substantial percentages c, the light reflected is either A)slowed because of Newtonian motion (don't shoot me as a "tired light" proponent yet, I know the quantum motive counter-response) or B)if c is truly constant, the propogation of the light "waves" (a wave being the frequency of light propogated in a given instant at c) become slower(longer) even though the photon "carrier" remains at c. I remember the example given about distant supernovae and the constancy of their respective durations even at great redshifts, but doesn't the supernova's powerful release of energy change things? They (the supernovae) are moving away from us, but if the light emitted by is typically redshifted under normal circumstances, could the supernova's intense force throw the light back toward us with enough energy to overcome the redshift, thus allowing it to arrive here in undistorted? The "wave", as it were, gaining sufficient energy in the blast to counter the otherwise high redshift. I have also seen the discussions about the Magellan clocks needing to be constantly resynched with Earthbound clocks, though I believe that might be explicable by the effects of gravity on the mechanism here on Earth as opposed to the flow of time being variable. I guess this puts me at odds with the mainstream, but I can live with that. I also suppose this isn't going to be settled for me in my lifetime. I really cannot be sure until humanity actually tries this kind of experiment in space, not likely for a century or two at best. Until then this will be my one point of nonconformity with the rest of the world. Thanks for the enjoyable roundtable. Your explanations were most helpful in understanding the current theories.