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imported_Voyager
2003-Aug-23, 08:57 PM
Ever since the sound barrier was broken, people have been asking: "Why canít we break the light speed barrier too, whatís the big difference?" It is too soon to tell if the light barrier can be broken, but one thing is certain -- itís a much different problem than breaking the sound barrier. The sound barrier was broken by an object that was made of matter, not sound. The atoms and molecules that make up matter are connected by electromagnetic fields, the same stuff that light is made of. In the case of the light speed barrier, the thing thatís trying to break the barrier is made up of the same stuff as the barrier itself. How can an object travel faster than that which links its atoms? But there might be a way... alter our molecular stucture. But how? Opinions wanted. Thanks, from Voyager

Locke
2003-Aug-24, 04:34 AM
Even if it is acheivable, your molecular structure would simply fall apart... i think. :ph34r:

Locke

imported_Voyager
2003-Aug-25, 12:08 AM
True. I can't think of any theory that can relate to that problem. According to the Fitzgerald theory, you would become smaller as you reach warp speed and eventually, become a singularity, or a subatomic particle.

ironpirate
2003-Aug-28, 11:13 PM
I tend to like the theory that Space can be folded and bent to reach locations normally to far away. Like taking a map of space, folding it and just go a to b. I've tried to read up on the theory, but it generally goes over my head. I understand the principle of it, just not the mechanics. Still it is very interesting to think about.

megaquark
2003-Aug-29, 01:07 AM
One of the problems we have here is that there are too many unknowns. Take this problem for instance. I'm no expert, but here is my understanding.
According to Einstein, an object's speed is relative to the speed of the observer. A spacecraft approaching another is effectively moving at about 3 ft per second although from an Earth observer's position, they are both moving at about 18,500 mph.
As I understand it, nothing in space can have a speed of 0. There are no reference points. There is no galactic center by which we can measure speeds.

This rule changes for some reason with light and I haven't researched it enough to understand why. Light speed according to Einstein is the only constant.
But is that light speed from the observer on Earth? What happens when you have two objects approaching each other at .75 light speed? Each one would see the other as approaching at FASTER than light speed. Or is there some magical force that makes the closing velocity exactly light speed no matter what you are approaching?
What reference point can we measure light speed against other than the light source?

So you are in a spacecraft and approaching a planet. As you approach that star system, the planet you are headed for is moving away from you. You get within a few mph of light speed and as you approach, the planet rounds its orbit and is now moving towards you. Your effective speed of approach is now light speed + as seen from an observer on that planet. Also, an observer from your planet would see you at + light speed it they were moving away from you.

His entire premise was also based on the e=mc^2 equation that pretty much prevents anything from getting to light speed because the energy required to move the mass to that speed requires too much mass to get to light speed.

Of course, he never considered an object being "pushed" by outside forces such as a solar sail.
SO we have to open our minds to the possibility that Einstein was only mostly right. Maybe light speed isn;t a constant. Maybe it is constant only in nature.
As we have shown many times before, nature only shows us the lower boundaries of the possible. We've seen it with transportation, agriculture and comminucation. We'll see more of that in the coming years when computers surpass our brain's abilities. Maybe it is just like the sound barrier where people simply couldn;t imagine the ability to move faster than the sound we made. That demon that existed at Mach 1, but didn't disappear. He just moved to 1c.

Fraser
2003-Aug-29, 02:57 AM
This is how time dilation comes in. In your scenario where two spacecraft are approaching each other at .75 c. The light still has to be moving at the same speed, so it's the time that has to slow down or speed up depending on whether you're watching from a spaceship or open space.

Cambo
2003-Sep-02, 12:30 AM
Hi all,
Fraser, why is it that "time" is the part of the equation that has to change? From my logic "time" is the constant, well my brain accepts that "time" is constant but speed isn't.
Who said "light" moves at a constant speed?
Why do we accept that "light" is the constant and "time" varies?
I'm not an educated person as far as University goes and most of what is expounded by others on this site leaves me totally befuddled.
If "light" is constant, why is it accepted that a red/blue shift of other stars indicates which way they are moving, toward/away, from us? Doesn't this suggest that "light" moves at various speeds? Or am I confusing speed with wavelength?
The questions go on the more I think about things.

Questions arising from letting the mind wander -:

Sound and light are measured in wavelengths. There are sounds both of high and low wavelengths we do not perceive with our ears. As wavelengths change do the properties of the wavelength change? If a sound wave frequency is increased does it go to the next 'level' and become a radio wave, or whatever is next?
Is 'light' the top of the wavelength tree?
If not what is? And what is stopping light becoming the next thing?
If a light wavelength changes there is an observable change in the colour of the light.
What happens if the frequency of the light wavelength is changed beyond the observed colour change?
My brain hurts, probably from bashing it against the brick wall called ignorance.

Planetwatcher
2003-Sep-02, 01:28 AM
If there was a way to make an object behave as though it had no mass, then a relitivly small amount of thrust energy could cause the object to move at tremendus speeds.

I read about this in Discover Magazine as one of several theorys being explored in thinking outside the box. The idea is if the inertia of an object can be temporarly nullified, then even a very massive object would act as though it had no mass, and acting like it had no mass would reduce it's resistance causeing it to take very little energy to cause propulsion, hence moving at least close to light speed could become achievable.

Sounds good on paper, but actually doing it is another matter. :rolleyes:

Deep_Eye
2003-Sep-09, 10:48 PM
Then is the speed of light relative or a set speed? I've heard lots of places that it's approximately 182,000 miles per second. I also saw somewhere else that the speed of light will increase as you put more energy into your attempts-which goes along the lines of what you were saying. What about then surrounding yourself in a field of anit-matter? Say....equal in proportion to your mass. Then traveling at light speed or even FASTER....maybe. We just can't manipulate anit-matter like we can regular matter. I've just always liked to think that light speed is a set speed.
What you were saying about 2 objects approaching at 75% the speed of light, it would appear you or the other object were moving faster, but thats just an illusion due to net force, which in this case would be 1.5x speed of light. That gets to be a pain typing out "speed of light" so many times. Why not come with an abreviation....such as "sol"? Any other ideas?

Planetwatcher
2003-Sep-10, 12:07 AM
We really can't use SOL because that is the name of our Sun. Why don't you just highlight the words speed of light, right click, and select copy.
Then every time you want to type speed of light, right click again and choose paste, and then just keep typing.

Light speed is constant at 186,000 miles per second. Or a little over 11 million miles per minute.
The two objects approaching each other do approach in the same amount of time as one object would at twice the speed. But neither object is actually traveling at twice the speed, so it is an illusion, but it is also a law of physics.

The speed increase of light as you approach speed of light is something I never heard of. But I do know it takes more energy the faster you go.

Like if you had a Ford Pinto with a 306 engine you could top out at a certain speed.
If you could and did put a 455 engine in the same car, you could top out at a faster speed. Why? Because the bigger engine provides more power, hence more energy. It takes more energy for the same size object to go faster.

Now as you approach the speed of light, the energy requirement to go any faster is greater then any energy source can provide, and more fuel then can possibley be made available. So much so that you would have to be able to litterally turn all the mass of the object into energy and still not reach 100% of the speed of light.

But in the theory I mentioned from the magazine, if an object acted like it had no mass then a small amount of energy can push it close to light speed. In theory.
But in reality it is a catch 22. To get the speed of light you need an infinite amount of energy. To convert that energy from mass, you would need an infinite amount of mass to become fuel and energy. Which means you need another infinite amount of energy, which requires another infinite amount of mass. . And so on.

Anti-matter is something a lot of people don't understand. They watch Star Trek and hear Capt. Kirk call for more speed and Scotty makes it happen.

In anti-matter the electrical charges work opposite and it's that simple, but making it happen is not that simple.

The atom has 3 parts to it,(except for hydrogen which has only 2)
A proton has a possitive charge, a neutron no charge, These 2 are at the center or nucleus of the atom. A smaller negitively charged particle called an electron orbits the nucleus.

In anti mater your nucleus still has neutrons, but insted of the positivly charged protons, they have negitivly charged particles the same size, called anti-protons because it is the opposite of protons. Orbitng insted of the negitivly charged electrons, you would have the same size positive particles called positrons.
These opposites tend to annilate each other if they meet, and in so doing release more energy then either object could by itself.

So an antimatter field around a space craft and not be done realisticly speaking.
The field would annilate the space craft.

I hate to bear the bad news, but beating the speed of light is not likely.

Josh
2003-Sep-10, 05:15 AM
I read through this and saw the word "warp speed" used. I have nothing to add about the light speed theories but ...

Warp speed and light speed are very different. Essentially in warp speed travel you don't move. what you do is move space. Or, more correctly, warp space - enlarging everything behind you and contracting everything in front. hence the word warp. That's where all the antimatter stuff above comes in. This is faster than light travel. The reason this is possible (theoretically of course!) and you aren't ripped apart or turned into energy or any of the other side effects of light speed travel, is that you create a "warp bubble" around you (also where the antimatter comes in) which basically is like enclosing yourself in a constant space and time. Once you've set your exit conditions (time wise etc) you change the space around you.

simple.

Faulkner
2003-Sep-11, 11:51 AM
Miguel Alcubierre has laid out the theoretical foundations for faster-than-light travel without offending Einstein...but technologically it might be a way off...?

http://www.astro.cf.ac.uk/groups/relativit.../miguel94a.html (http://www.astro.cf.ac.uk/groups/relativity/papers/abstracts/miguel94a.html)

He uses the "warp bubble" idea (I think)... His idea is that during the inflationary stage of the early universe, space-time expanded faster than light. So while objects moving thru space-time can't exceed light-speed, space-time itself could be made to move at infinitely high speeds... (or something like that)...

I'm optimistic that we'll break the "light barrier" one day. Maybe we already have? Maybe "they're" keeping it a secret?? :huh:

traintaz
2003-Sep-13, 12:02 AM
If light speed is a constant then I&#39;m really confused why light can slow down when it passes through glass and resume its original speed when it exits the glass? <_<

Aiz
2003-Sep-13, 11:03 AM
traintaz,


If light speed is a constant then I&#39;m really confused why light can slow down when it passes through glass and resume its original speed when it exits the glass?

If I remember correctly my physics lessons:

"Light speed is constant", but there&#39;s a second part to that statement - "while traveling within the same medium".

What it means is:

If we let speed of light = C

If light is travelling in medium 1, it&#39;ll have a constant speed of C1
If light is travelling in medium 2, it&#39;ll have a constant speed of C2

It just so happens that:

If medium 1 = vacuum
C1 = ~186,000 miles/s

So, light speed IS constant even within a block of glass, depending on the density of that glass. And you can&#39;t go faster than that (unless you use a warp engine in that block of glass).

scott712
2003-Sep-14, 04:16 AM
Normally when one is accelerating they experience inertial forces, however, not when they are accelerating in freefall. When you are in free fall you feel as though you are not moving at all.

I think it is analogous to a balloon driven by the wind. The passengers do not feel the wind. I am not trying to say that Space is an ethereal substance, but rather that, paradoxically, the real stationary frame in a gravity field is experienced only in free fall.

I&#39;m saying all that to make the point that if we succeed in generating a gravity like field, then we can free fall all the way to our destination at any arbitrary speed because in our own frame of reference we won&#39;t be moving at all&#33; I think we are only limited by factors such as gravity differences between our head and our feet tearing us apart at higher gravitational gradients.

scott712

Deep_Eye
2003-Sep-16, 12:51 AM
Ahhh&#33; Thanks Aiz&#33;&#33; This topic has been the source of many headaches for me. Light is like sound in that its speed is constant in its own medium to put it in your words. Sound travels SLOWER under the ocean that at sea level, ect. Thanks&#33;

eggplant
2003-Sep-20, 09:01 AM
Just read the thread and got lost in the following one. I have thought on a few of these things before.
I&#39;ve always liked the gravity focusing ideas but I&#39;m not sure that will pull you through the hose. But if you can focus a gravity field to a point to the exclusion of all others, or isolate a small gravity field and then amplify and project it, you&#39;ll certainly get moving pretty fast... (I think?)
Didn&#39;t Einstein also say something to the effect that, that E=Mc2 while a useful descriptor in the development of Physics, must surely only apply in "real time". Because of the issue of it only achieving light speed? And wasn&#39;t this the birth of Quantum mechanics? The Tachion (sp) universe? I&#39;d have to start with What if E doesn&#39;t = Mc2, Can an object move faster than it&#39;s fuel can burn out it&#39;s exhaust? Can light = the resistive force, or better said is there really no resistance in space? I&#39;d be guessing no the more I read. I think of it as a pool and light&#39;s the water. You have to push off it to go faster than it. (The light spitting engine intrigued me)
Mastering galaxial travel requires at least on of the leaps, time bending (as speed is measured in time if you remove it from the equation you&#39;re left with a distance.), Space bending (remove both), or logrymthic over light speed acceleration.
While time is a random agreement of how long a second lasts, and a function of the equipment we have to observe it (ourselves), it begs the observation that when you&#39;re going faster than it you should be able to observe the past as its reflection (light) moves away behind you. This put&#39;s time and light as equals in velocity... Because what we see is the time passing backwards to our, over the speed of light, destination. (but we&#39;re still getting older)
Suppose I want to go to that star, no the kinda bright one up there, right. But it&#39;s really over there, that star has moved X amount of years when I&#39;m looking at it. So you can do the math to find out at which speed you would have to go to reach it at where it is when you get there i.e. if it&#39;s 10 light years away and you want to be there in 1 year you need to go 10 times the speed of light, and aim a little to the right... and when you get there you&#39;ll see our sun 9 years ago...(simple like chasing down planets in there orbits at much lowers speeds.) sorry getting lost. Point being perception. Everything that we see is a reflection of light. And that&#39;s our perception of it Like it was described so eloquently up the thread, we think we can&#39;t and time can&#39;t wait...
I think we can, I&#39;m just pretty sure the apples not gonna drop on my head. Space does warp, it&#39;s just in black holes it looks like it would hurt... And I&#39;m betting an orange is still an orange at any speed it moves. Just that our senses do not allow us to recognize that it&#39;s atoms are all spread about.
The universe is no larger than my ignorance of it ;) In the future (where it&#39;s lighter) I&#39;ll try not to demonstrate it so long windedly...

Calibre
2003-Oct-01, 07:16 AM
With in the last year I remember seeing a new article on TV about some scientists in Australia TELEPORTING a light beam.

Which then raises some questions.

A) If light can be teleported does it get from A to B at lightspeed or instantly?

B) Does any energy pass between the two points, or does the energy simply change coordinates?

C) If Energy can be teleported, then can matter?

D) Even if only energy can be teleported could one send enough to refuel/power a space probe during its flight?

Haglund
2003-Oct-08, 08:39 AM
In this spacetime, under normal conditions, it is impossible for matter to reach the speed of light. It&#39;s just the way it is. The difference between the sound barrier and the light barrier are huge. They are two different concepts. One is dependent on the atmosphere of the planet where the intelligent species, who attempts this, live. The light barrier is the same everywhere and is impossible to break.

Matthew
2003-Oct-08, 10:08 AM
Originally posted by Calibre@Oct 1 2003, 07:16 AM
D) Even if only energy can be teleported could one send enough to refuel/power a space probe during its flight?
If we could transport energy to refill a space probe (or ship) we could send them much further in space. But they would still need a fuel source, so unless we could devise an engine which ran totally on energy it would still need to refuel.

If &#39;transporting&#39; was instantaneous then data could be relayed between probe and earth intantly and we would need to wait for data to travel back to Earth. All very interesting...

SOMSOC
2003-Oct-12, 03:29 PM
How can we achive the spped of light if light travels flat?.

SOMSOC
2003-Oct-13, 12:19 AM
I have read some interesting ideas on alternative travel in space

Someone mentioned surrounding a craft in anti-mater equal to it&#39;s mass I might be wrong but producing anti mater would be a costly exercise, I read somewhere I can&#39;t remember though...that to produce 0.0001gms of anti-mater would cost &#036;100,000,000,000, let alone surround a craft that would wiegh tons and tons.

Solar sails controlled by a laser from earth, surley the energy requirments to guide a laser to a solar sail would be beyond our capicity.

Nucler fussion is way too dangerous to experiment with, an accident could destroy our atmosphere,or severly damage it ps I am not an expert in any of this, I am just throwing out my ideas, I love to hear all the great responses.

Planetwatcher
2003-Oct-13, 03:03 AM
I aggree with Parker on this one. As much as we&#39;d like, we can not change the laws of physics. :(

However, all the theories propounded about relitivity, and quantium machanics use the speed of light as their reference point, and treat it as &#39;the impossible speed.&#39;
And perhaps they have the math to back it up, but I wonder if light&#39;s velocity is really &#39;the impossible speed&#39; or could the real &#39;impossible speed&#39; be faster then light, but it&#39;s just that light is the fastest thing that we can detect.

Which in itself could mean the propounders of relitivity, and quantium machanics have assumed light&#39;s velocity as the impossible speed for lack or a better and real reference of something which may be faster. B)

But again I won&#39;t pretend to know since I am not educated in that kind of math. I just thought it may be an interesting question to pose. ;)

SOMSOC
2003-Oct-13, 03:06 AM
Very well put planet watcher.

Thanks

Matthew
2003-Oct-13, 10:11 AM
We don&#39;t know all of physics, all of quantum physics.

But planetwatcher, we cannot change the laws of physics, but what if we don&#39;t know the laws of physics? Maybe there is some by-law (sounds like i&#39;m a politician) that we don&#39;t know.

Quantum Complex
2005-Aug-25, 04:32 AM
I created a similar thread. I truly believe the speed of light is achievable. To think that going at the speed of light turns you into energy is nonsense by the famous theory of Einstein&#39;s E=MC^2. I believe travelling at the speed of light has 3 simple downsides.

1. Intense gamma radiation is produced
2. The power needed to go at that speed is enormous, the only possible way to do it as far as I know is by using anti-matter, which is incredibly dangerous.
3. At the speed of light collision with space-dust will tear apart your vehicle.

Quantum Complex
2005-Aug-25, 04:35 AM
Oh, and voyager, sound is matter if I remember correctly.

Planetwatcher
2005-Aug-25, 08:39 AM
I too believe that light speed can and some day will be achieved. But not by any current technology, and certainly not in this century.
Just this week were articles saying that there are methods of slowing down, or speeding up light, so it&#39;s no longer the constant we always thought it was.

Tacyon particles are believed to travel faster then light. I once read of a figure of up to 350 times light&#39;s velocity, but I don&#39;t remember where I found it so I can not provide documentation.

To get to or above the speed of light, we have to think outside the box.
What&#39;s the greatest detourent from reaching such speeds?

Simple, the mass of the object, probe, or ship we would accelerate to such speeds.
As speed increases, so does the mass, which requres ever greater amounts of energy to continue acceleration. Eventually the mass becomes so great, that all the energy in the univers wouldn&#39;t make it go any faster. So a means needs to be found to deal with the mass.

Now, suppose there was a way to neutrualize the mass of a space ship?
Think about the space shuttle with it&#39;s powerful engines. What if the whole thing could be made to weigh less then a bird&#39;s feather?
How much faster it could go. How much farther the fuel would take it.

Now what if the space shuttle had ion engines instead of rocket boosters, and still weighed almost nothing?

Ion engines are very slow in accelerating because of the vehicle&#39;s mass, but if it had no mass, what would that acceleration be like?
Top speed would be the very speed that the ions move, and the fuel driving ion engines will last hundreds of years as it is.

Of coarse this means some how changing the laws of physics, but who knows what kind of technologies our decendents will have at their disposial?

But that&#39;s the most promising means of achieving great speeds that I can think of.

astromark
2005-Aug-25, 09:40 AM
A young woman I once worked with asked me how to lose waight. She dident need to, but I said "You could loose about eight pounds real easy. Just cut off your head." She has&#39;ent spocken to me since....
This is of corse not a exeptable method of sheding mass. So how can we breack the laws of phisics.
As for the problem of colisions at these speeds with minute particles. Could you project a plazma field a head of your space craft. To clear the way. Tachion energy? Hmmmm . . . need more coffee.

Planetwatcher
2005-Aug-25, 09:51 AM
I don&#39;t know. Perhaps some type of magnetic or energy field, or a means to make anti-gravity.
It&#39;s too early for me now, Need sleep.

Sp1ke
2005-Aug-25, 04:13 PM
It wouldn&#39;t be enough just to lose some weight to reach light speed. You&#39;d have to become completely massless like a photon. If there&#39;s just the slightest bit of mass left, this would still scale up to an infinite mass as you reached c.

Tachyons that always move at greater than light speed have been proposed but, as far as I know, are only a theoretical idea and have no evidence for their existence.

Thing is, if you could move at 99.9999% of c, a trip to the nearest star would be quicker (it would only take a few years) but a] it would still take a huge time to reach another galaxy, and b] everyone you knew back on earth would age much faster than you and would probably all be dead by the time you got back home. So it&#39;s pretty much a one-way trip so is there any point?

[Edited to correct a typo]

cran
2005-Aug-25, 06:09 PM
:huh: Why is this thread here in "Other Stories"?
...and not in, say, "Questions and Answers"? :unsure:

... tachyon-drives? ... antimatter shells? ... bending space? ... separating intertia from mass? ... focussed gravity? ... dimension-hopping? ... scale-translation? ... teleportation? ... wormholes? ... I guess something&#39;s gonna work ... sometime ... :)

Quantum Complex
2005-Aug-26, 02:35 AM
I agree with planetwatcher, true zero-g will take you to lightspeed unlike the 0-g we feel in space.

alainprice
2005-Aug-26, 04:03 AM
If you could travel at 99.9999% of the speed of light, you would cover 4 lightyears(as measured by earthbound observers) in a lot less than 4 years.

cran
2005-Aug-26, 05:46 AM
Originally posted by alainprice@Aug 26 2005, 12:03 PM
If you could travel at 99.9999% of the speed of light, you would cover 4 lightyears(as measured by earthbound observers) in a lot less than 4 years.
Actually, it&#39;s the other way around... to the traveller it would be much less than 4 years; to earth-bound observers, it would be almost exactly 4 years (very slightly more), and it would be a further 4 years before any information from the traveller gets back to the Earth... <_<

Planetwatcher
2005-Aug-26, 10:32 AM
Why is this thread here in "Other Stories"?
...and not in, say, "Questions and Answers"?

Simply because the Questions and Answers section did not yet exist when this tread was started. This is among the oldest threads in the forum. Someone did a lot of digging to find it.

But it does relate back to a story which was promenent at the time. I don&#39;&#39;t see much reason to change it now.

cran
2005-Aug-26, 11:02 AM
Oh, okay, that&#39;s fine...
I just hadn&#39;t seen it before, and couldn&#39;t find a story link on the first post, so it looked like a new thread...
no drama... :D

ASEI
2005-Aug-27, 12:38 AM
I think we need to be able to walk before we run. I wonder if anyone has any good ideas for implementing a propulsion system to reach even half of lightspeed.

antoniseb
2005-Aug-27, 07:54 PM
Originally posted by ASEI@Aug 27 2005, 12:38 AM
any good ideas for implementing a propulsion system to reach even half of lightspeed.
I&#39;ve seen a few things that look plausible, but not very easy.

There are a bunch of research grants out now for ways to collect positrons and/or anti-protons. If we can find a nice dense way to store these things it should be possible to build a thing which can get over 0.5c and then slow down again.

Similarly, it might be possible to build something that is kind of like a solar sail, except that it concentrates light to power a device which magnetically scoops interstellar gas and blows it out the back at 0.9c. This would require beaming energy to the craft from home, but would also enable it to use power from home to slow down at the other end of the trip.

If the probe is a bullet-sized nano-factory that can take 1000g&#39;s of acceleration, you could possibly build a magnetic impulse rail gun in space 11 million kilometers long (about 1/12th the distance to the Sun). It would get your projectile up to 0.5c in under 2 hours of 1000g acceleration.

cran
2005-Aug-27, 10:03 PM
While we wait for nanotechnology to develop the sophistication and reliability needed for high g deep space probes ... would it be worthwhile investigating/developing probes or remote investigations based on pulsed lasers? :huh:

Guest
2005-Aug-28, 12:47 AM
Originally posted by antoniseb@Aug 27 2005, 07:54 PM
Similarly, it might be possible to build something that is kind of like a solar sail, except that it concentrates light to power a device which magnetically scoops interstellar gas and blows it out the back at 0.9c. This would require beaming energy to the craft from home, but would also enable it to use power from home to slow down at the other end of the trip.

An interesting idea;
I made an image of a similar type of ship a while ago
(here it is) (http://img66.imageshack.us/img66/7726/beamrider0fi.jpg)

however the collimation of the beam would need to be remarkable if you propose to beam power to the probe during the deceleration phase.

Planetwatcher
2005-Aug-28, 09:58 PM
If the probe is a bullet-sized nano-factory that can take 1000g&#39;s of acceleration, you could possibly build a magnetic impulse rail gun in space 11 million kilometers long (about 1/12th the distance to the Sun). Would such a device have to be in a straght line? If it were concentric like a giant ring, with a movible exit point to launch from? It wouldn&#39;t have to be nearly as large, plus you could accelerate the probe to much greater speeds before it launched from the accelerator.

On the down side. This would be the only controled acceleration, and or manuver.
Once released, the probe becomes a total victum of the elements.
At best, a launch trijectory could be programed to send the probe in such a direction as to get gravity assists from outer planets.

But I&#39;m not sure that would be very helpful to a bullet sized probe, and especially if it is already travelling a significant fraction of light speed.

Another possibility is if very compacted solar/light sails could be squeezed into the body of the probe, to initiate sometime after launch, some sort of acceration, or holding top speeds would be possible until the probe passes through the middle part of the Solar System, at which point the light power to the sails would decrease enough that the sails would no longer be effective, and could even drag the speed down.

But any of this, let alone all of it is decades away, if ever.

Red Hot Chili
2005-Aug-28, 10:55 PM
Comon sense suggest not. The human body can only withstand so many Gs. A fighter plane pushes the boundry of what the human body can take, think of what the speed of light would do, we would be flattened into nothing.

cran
2005-Aug-29, 01:25 AM
I made an image of a similar type of ship a while ago thank you, guest... sorry we didn&#39;t acknowledge it earlier :) I see you incorporated a &#39;dust deflection beam&#39; ... wouldn&#39;t that partially offset the acceleration you are trying to achieve? Not by much perhaps, but some? :huh:


Would such a device have to be in a straght line? If it were concentric like a giant ring, with a movible exit point to launch from? It wouldn&#39;t have to be nearly as large, plus you could accelerate the probe to much greater speeds before it launched from the accelerator. Based on the big particle accelerators idea...? Hmm, Planetwatcher, that&#39;s a thought... :)

Red Hot Chili, I don&#39;t think any of the last few posts at least were contemplating human passengers or pilots... the probes being considered here would be small enough to hold in your hand ... :)

ASEI
2005-Aug-29, 02:14 AM
Comon sense suggest not. The human body can only withstand so many Gs. A fighter plane pushes the boundry of what the human body can take, think of what the speed of light would do, we would be flattened into nothing. Speed&#39;s harmless. It&#39;s acceleration that generates the forces on the body. If humans are to accelerate up to lightspeed, it would have to be gradually, over the course of years.

cran
2005-Aug-29, 03:15 AM
Originally posted by ASEI@Aug 29 2005, 10:14 AM

Comon sense suggest not. The human body can only withstand so many Gs. A fighter plane pushes the boundry of what the human body can take, think of what the speed of light would do, we would be flattened into nothing. Speed&#39;s harmless. It&#39;s acceleration that generates the forces on the body. If humans are to accelerate up to lightspeed, it would have to be gradually, over the course of years.
Actually, ASEI, it&#39;s not as long as you think ... constant acceleration at ~1g (roughly 10m/sec/sec) would bring you close to c in less than 1 year ... I did the calculation years ago ... it&#39;s not so much the time it takes to achieve the velocity ... it&#39;s the energy you need to maintain the constant acceleration ... and that energy requirement begins to increase exponentially as you (or your ship) reach relativistic velocities ... significant fractions of c. :)

ASEI
2005-Aug-29, 03:46 AM
Oh yeah. You&#39;re right. Still, for a propulsion system that could do that&#33; The solar system would be ours&#33;&#33;

XENON_PLASMA
2005-Sep-06, 01:18 AM
How about using gravity as a means to "pull" yourself forward and accelerate to ~c

I know we still have to determine whether "Gravitons" exist or not (well isn't that what LIGO is for?) and whether gravity behaves like a particle or a wave (such as light behaves) but wouldn't this be feasible as a means of FTL travel?

Darth Maestro
2005-Sep-06, 01:44 AM
What about navigation?? if you are travelling at such a speed as a mass ... how would you withstand any movement by the spacecraft other than it going in a strait line? Wouldn't making a turn at anywhere even close to the speed of light send you in the tangent direction of the turn itself. Space is big, but the speed of light is fast ... surely you'd need to make a few turns along the way.

CHEERS

ASEI
2005-Sep-06, 03:18 AM
How about using gravity as a means to "pull" yourself forward and accelerate to ~c
This is that old unpaired forces fallacy. It is functionally equivalent to having a charged spacecraft pull itself forward with a concentrated charge in front of it, or having a spacecraft on a spring pull itself forward by the spring force. The gravitational force on the spacecraft is equal and opposite to the gravitational force on your gravity source (generator, whatever). The two forces cancel out if the generator is attached to the ship.

It may be possible to create a "warp drive" (see Alcuibeirres warp drive) which distorts space and causes a region of it to be stretched with respect to the 'stationary frame'. But this doesn't help propel your ship. At best it would amplify your velocity and acceleration. I still don't get how it is supposed to push it beyond c. It seems to me like it would just be distorting the space and time inside the bubble from an outside perspective.


What about navigation?? if you are travelling at such a speed as a mass ... how would you withstand any movement by the spacecraft other than it going in a strait line? Wouldn't making a turn at anywhere even close to the speed of light send you in the tangent direction of the turn itself. Space is big, but the speed of light is fast ... surely you'd need to make a few turns along the way. Depending on what sort of propulsion you're using, turning after the initial acceleration may or may not be feasable. Turning requires thrusting or propelling tangent to your current velocity. Your velocity will only change direction at a rate proportional to your acceleration and inversely to your speed and not very fast at the speed you're going. dtheta/dt proportional to a/v.

The speed of light is fast, but compared to interstellar distances, it still takes you years to get anywhere. (Well, years compared to the reference frame of earth, but that's an entirely different issue.)

radioastronomer
2005-Sep-06, 04:28 AM
The lorentz transformation will not allow you to achieve the speed of light.

radioastronomer
2005-Sep-06, 04:33 AM
It wouldn't be enough just to lose some weight to reach light speed. You'd have to become completely massless like a photon. If there's just the slightest bit of mass left, this would still scale up to an infinite mass as you reached c.

Tachyons that always move at greater than light speed have been proposed but, as far as I know, are only a theoretical idea and have no evidence for their existence.

Thing is, if you could move at 99.9999% of c, a trip to the nearest star would be quicker (it would only take a few years) but a] it would still take a huge time to reach another galaxy, and b] everyone you knew back on earth would age much faster than you and would probably all be dead by the time you got back home. So it's pretty much a one-way trip so is there any point?



If Tachyons exist, we should have seen evidence for them similar to Cerenkov radiation emanating from the core of a bathtub reactor.

snabald
2005-Sep-06, 06:48 PM
Sound and light are measured in wavelengths. There are sounds both of high and low wavelengths we do not perceive with our ears. As wavelengths change do the properties of the wavelength change? If a sound wave frequency is increased does it go to the next 'level' and become a radio wave, or whatever is next?
Is 'light' the top of the wavelength tree?
If not what is? And what is stopping light becoming the next thing?
If a light wavelength changes there is an observable change in the colour of the light.
What happens if the frequency of the light wavelength is changed beyond the observed colour change?
My brain hurts, probably from bashing it against the brick wall called ignorance.

Sound "waves" are just the oscillations of pressure in air (or what ever medium they [the pressure waves] are traveling through), that are produced by vibrations, light and radio waves are part of the electromagnetic spectrum, a sound wave can't become a radio wave. The "sound" (pressure waves caused by vibration) would just become higher and higher in wavelength (errr... that is the wavelength would become shorter and shorter).

digger1948
2005-Sep-06, 08:16 PM
If Tachyons exist, we should have seen evidence for them similar to Cerenkov radiation emanating from the core of a bathtub reactor.
We didn't see Cerenkov radiation until we learned to produce,use and store fissile material.Definitive denials fare badly in the history of science.

radioastronomer
2005-Sep-06, 10:42 PM
We didn't see Cerenkov radiation until we learned to produce,use and store fissile material.Definitive denials fare badly in the history of science.

However, since we do not see Cerenkov radiation in a vacuum (we have looked), the likelihood is they do not exist.

ASEI
2005-Sep-07, 12:52 AM
However, since we do not see Cerenkov radiation in a vacuum (we have looked), the likelihood is they do not exist. Unless they don't interact with normal particles to produce photons. Of course, that could almost be functionally equivalent to not existing.

piersdad
2005-Sep-09, 08:10 PM
some thing i wondered about
is what would happen at the speed of light
(if you could travel at that speed)
the hydrogen atoms in the space would become lethal cosmic rays.
and any dust encountered would pass through anything it hits