FTL - New Thoughts and Questions

[mars_or_die]

I have always been fascinated with the idea of traveling thru space, exploring "strange new worlds" and "going where no man (or women) has gone before". After years of reading, thinking and studying the concept of Faster than Light travel I had almost given up on the possibility of it ever being possible to travel thru space fast enough to make space exploration a reality. Then something hit me.<br /><br />According to our currently accepted "Theory of Relativity" and "Theory of Special Relativity" it is IMPOSSIBLE for an object to ACCELLERATE to the speed of light. Notice I capitalized ACCELLERATE. However, when you think if it like that a new question arises.<br /><br />CAN ANYTHING TRAVEL FASTER THAN LIGHT? By that I mean is there anything in the universe that in its natural state has a speed in excess of that of light. I dont mean something capable of accellerating to a ftl speed. I mean something that is ALWAYS at an FTL speed or something that can INSTANTLY be at an FTL speed.<br /><br />There have been discussions on the theoretical possibility of TACHYONS and from what I have heard/read they are at expected to be at a constant speed in excess of c. Which leads me to a slew of new and mind-boggling questions.<br /><br />1.) Is there any strong scientific basis for the belief in the existence of anything traveling ftl like Tachyons?<br />2.) What is a Tachyon theorized to be, is it energy, light, plasma, WHAT?<br />3.) Is it believed that a Tachyon has ALWAYS traveled FTL and if so WHY?<br />4.) Is it theoretically possible to create a Tachyon?<br />5.) Is it theoretically possible for a Tachyon to carry data, energy, etc. with it at FTL?<br /><br />Now back to the main subject at hand. Traveling Faster Than Light!<br /><br />Okay so we can't accellerate to FTL speeds due to an infinite mass and thus require an infinite source of energy. However, is it theoretically possible (given our current understanding) that something could go from rest to c INSTANTLY, or from rest to &g

 

[mlorrey]

Actually relatively says you cannot travel AT the speed of light. It says nothing about accelerating up toward it, other than saying that it gets progressively more difficult and energy demanding.<br /><br />You do not need to exceed light speed to travel interstellar distances. Reaching the 90-99% of light speed range is all that is required, in order to dilate time enough that long distances can be crossed in subjectively little ship-board time.<br /><br />It is unrealistic to seek to travel across the galaxy and be back in time for your kids graduation, unless you take them with you. That is the price of real interstellar travel: expect everyone you ever knew to be dead long before you get back, if you get back.

 

[bonzelite]

gravity violates GR. it acts instantly.

 

[mlorrey]

No, it doesn't act instantly. If it did, then Mercury would not exhibit frame dragging in its orbit around the sun, neither would the galaxy as a whole in its orbit around its central black hole.

 

[derekmcd]

Newtonian gravity = instant. Relativity = speed of light. No technology that exists today can verify either. I imagine to make a statement either way is conjecture. <div class="Discussion_UserSignature"> <div> </div><br /><div><span style="color:#0000ff" class="Apple-style-span">"If something's hard to do, then it's not worth doing." - Homer Simpson</span></div> </div>

 

[harmonicaman]

<i>"Gravity violates GR. it acts instantly."</i><br /><br />I think this is an illusion caused by the fact that the mass in the universe is static while space and time constantly expand.<br /><br />All the mass in the universe was created during the big bang event and it hasn't changed; only the time and space are growing all around it. What appears to us as an instantaneous gravatational effect is merely the expansion of time and space that has been eddying around the static mass in the universe for about 13.7 billion years.<br /><br />What we observe as instantaneous gravitational action is actually fossil gravity that has been around since time began and the expansion of space had to start eddying around this unchanging mass.<br /><br />(IMO) <br />

 

[mlorrey]

"Newtonian gravity = instant. Relativity = speed of light. No technology that exists today can verify either. I imagine to make a statement either way is conjecture. "<br /><br />On the contrary, we have technologies today that have made the statement. The Gravity B probe, for instance, has been able to measure frame dragging in orbit around Earth, conclusively proving the relativistic limitation on gravity.

 

[mars_or_die]

There is actually a very good reason to want to travel faster than light. At 90% of c it would take:<br /><br />* 4.62 years to reach the nearest star (not counting our sun) which is Proxima Centauri<br />* 4.73 years to reach Rigel Kentaurus (Alpha Centauri A or B)<br />* 6.6 years to reach Barnard's Star<br />* 9.46 years to reach Sirius A or B<br />* 12.54 years to reach Procyon A or B<br />* 28,600 years to get from our Sun to the center of the Milky Way.<br />* Approximately 200,000 years to reach the nearest Galaxy to Earth (Large Magellenic Cloud)<br /><br />Now the thought of exploring the universe consumes most of my thought, but I'll be danged if Im gonna spend 200,000 years of my life just to get to the nearest galaxy.<br /><br />The truth of the matter is that until we:<br /><br />A.) Discover a way to travel in great multiples of c, and/or<br />B.) Discover a way to shrink the distances between the celestial objects (I.E. - A worm hole of sorts)<br /><br />We will never truely be able to explore the heavens.<br /><br />With that said, imagine if you would the following scenario (this is ALL FICTION and just an EXAMPLE of what could happen):<br /><br />In 2020 a young physics student at MIT is working on a way to contain a nuclear reaction of great magnitude using only an electro-magnetic field. The field itself is designed to harness the power of the reaction to strengthen itself and produce additional electricity. By sheer dumb luck he trips and his new ink pen that is made of some strange alloy flies towards the containment field. The instruments in his lab record the pen exiting the field at exactly .00001 seconds after it entered, but the containment field is several hundred yards wide. By total accident this student has just stumbled upon a way to shrink the distance between two points in space.<br /><br />By 2030 this new discovery is being used to explore the outer reaches of our solar system. With round trip missions to other planets and comets in the Milky Way taking

 

[mlorrey]

"There is actually a very good reason to want to travel faster than light. At 90% of c it would take: <br /><br />* 4.62 years to reach the nearest star (not counting our sun) which is Proxima Centauri <br />* 4.73 years to reach Rigel Kentaurus (Alpha Centauri A or B) <br />* 6.6 years to reach Barnard's Star <br />* 9.46 years to reach Sirius A or B <br />* 12.54 years to reach Procyon A or B <br />* 28,600 years to get from our Sun to the center of the Milky Way. <br />* Approximately 200,000 years to reach the nearest Galaxy to Earth (Large Magellenic Cloud) "<br /><br />Wrong. Those times are how long it would appear to people left on Earth. On board ship, it would take less time due to relativistic time dilation, and the longer your trip, the more time you have to accelerate to higher velocities.<br /><br />At 90% of c, your gamma is approximately 2.5, so a 4.2 light year trip to Proxima Centauri would take 1.68 years of shipboard time.<br />* Barnards Star: 2.64 years<br />* Sirius A and B: 3.8 years<br /><br />These trip times would be if you were able to reach 90% of c relatively quickly after starting out, and then coasted in free fall from there on til your destination. More likely, you'd be in constant acceleration at a low acceleration level, so the trips to the closer stars would take a significant time, the longer trips would take far less time than their distance since you'd be able to accelerate for a lot larger distance.<br /><br />This wikipedia page has a pretty good explaination of an antimatter rocket system. Using such technology in a four-stage starship, you could travel to Alpha Centauri reaching a peak speed of 87% of c, an acceleration of at least 1/3 of a G, and which would give you a gamma of 2 for time dilation purposes. Thus, you should be able to reach Alpha Centauri in about 2.5 years.

 

[derekmcd]

<font color="orange">On the contrary, we have technologies today that have made the statement. The Gravity B probe, for instance, has been able to measure frame dragging in orbit around Earth, conclusively proving the relativistic limitation on gravity.</font><br /><br />Could you provide a link to that? I can't seem to find anything conclusively proves that gravity propagates at the speed of light. I, personally, believe it does, but have never seen any direct evidence. <div class="Discussion_UserSignature"> <div> </div><br /><div><span style="color:#0000ff" class="Apple-style-span">"If something's hard to do, then it's not worth doing." - Homer Simpson</span></div> </div>

 

[toymaker]

However according to our current knowledge and technical know how only 25c is the maximum speed you can safely go(or even less) and we are able to reach in theory.<br />Still enough to explore other solar systems.<br />They were such discussions here on forum before, which were quite informative.

 

[why06]

If it would take all the power in the universe to accelerate to the speed of light technically a tachyon would have all the power of the universe and more an infinite source of energy. The same rules must apply for the tachyon as regular matter except flipped around. It would take all the power in the universe to decellerate a tachyon under thespeed of light. I f this was true then, like a tachyon could instantely increase the speed of matter, matter could instantely decrese the speed of tachyons. Instanetly they would swich places. and because relatively to matter tachyons have all the power of the universe and more a craft coulbe instanetly accelerated to faster than light speed. Than it would use a n electromagnetic field to prevent any matter from touching it .<br /><br />Unfortanetely this idea requires a pre- existing amount of tachyons <br />Or a belief that an equal amount of FTL material was created and Slower than light matter and that matter was constantly shifting in and out of these two states due to the constant colisions of ftl matter and stl matter!<font color="yellow"><br /><br /></font> <div class="Discussion_UserSignature"> <div>________________________________________ <br /></div><div><ul><li><font color="#008000"><em>your move...</em></font></li></ul></div> </div>

 

[bonzelite]

<font color="yellow"><br />No, it doesn't act instantly. If it did, then Mercury would not exhibit frame dragging in its orbit around the sun, neither would the galaxy as a whole in its orbit around its central black hole.</font><br /><br />gravitational influence upon the planets would cease immediately, faster than light speed, were the sun to be removed instantly. <br /><br />

 

[h9c2]

"gravitational influence upon the planets would cease immediately, faster than light speed, were the sun to be removed instantly."<br /><br />This would be the most direct measure, but also the one that is completely unobtainable. As far as I know, the speed of gravity is still unknown, but count me in the camp that says that frame dragging is highly indicative of a limitation to the speed of gravity.

 

[mlorrey]

As it is, the best calculations of orbital objects that most accurately reflect real observations of the planets, asteroids, and comets shows that one must factor in relativities prediction of light speed limits on gravitational propagation to accurately predict how n bodies in a system will behave. Difficulties in exact predictions result from inexact observations as to the absolutely exact locations and masses of ALL of the various bodies of the solar system. Particularly as with bodies we do not even know about yet, their influence is a serious problem, particularly on objects far out in the KBO.

 

[yevaud]

A few years ago, Astronomers compared the speed of light from a distant event while also measuring the event via gravitational lensing. They concluded that there was no difference between the two, which means that gravity does not appear to propogate faster than the speed of light. <br /><br />This may well change when (if) the Higgs Boson is finally detected, and it's properties known. But as things stand now, observational evidence says no. <div class="Discussion_UserSignature"> <p><em>Differential Diagnosis:  </em>"<strong><em>I am both amused and annoyed that you think I should be less stubborn than you are</em></strong>."<br /> </p> </div>

 

[bonzelite]

here is some food for thought:<br />link<br /><font color="yellow">After thinking about the problems for 10 years, he published the general theory of relativity. In it, he suggested that gravity is not a force, as Newton had believed, but the result of a curvature of the space-time continuum -- the four dimensional world in which we live. He used a thought experiment to compare the force felt from gravity with acceleration. Imagine you are in an elevator and feel what you believe is the force of gravity, holding you to the floor. According to Einstein, since you cannot see outside the elevator, you cannot tell if you are feeling the force of gravity or if the elevator is being pushed toward your feet. Einstein stated that the two forces are actually identical. Furthermore, if you were in the elevator accelerating upward and a beam of light entered the elevator parallel to the floor, the light beam would appear to bend downward. This meant that light, which ordinarily traveled in straight lines, could curve if it traveled across a gravitational field. This curving path of light meant that that "field" was really a curving of space, which Einstein found was inseparable from time. The curvature would be caused by bodies with great mass.</font><br /><br />ok, Einstein was on to something when he suggested that gravity is not a force, as Newton had believed. i tend to believe that, as he just proved it thusly: <i><b> He used a thought experiment to compare the force felt from gravity with acceleration.</b> </i><br /><br />that is, gravity and acceleration are identical. and acceleration is purely geometric, not mass-dependent. you can attain the same "gravity" if you are accelerated in an elevator --that which being far less massive than the earth-- <i>rendering the same effect.</i> ----><font color="yellow"><b>" According to Einstein, since you cannot see outside the elevator, yo</b></font>

 

[spacechump]

<i>highlight this: The curvature would be caused by bodies with great mass... is erroneous. the article should have said "the curvature would be caused by bodies with great acceleration." gravity and acceleration are the same thing. mass does not matter. the elevator does not need to be the mass of the earth to create the 9.8m/sec^2 effect.<br /><br />mass has nothing to do with it. acceleration and gravitational force are not only similar, they are the same thing. therefore, the instant this hypothetical "elevator" is "removed," ie, the acceleration, the effect experienced would be instantly removed and the person would be free-floating and gravity-free immediately. mass and speed of light have nothing to do with it.</i><br /><br />I ask you this. Show us the calculations that the earth and a hollow sphere of styrofoam the size of the earth and a kilometer thick would produce the same acceleration on an object with 10 kgs of mass.

 

[bonzelite]

the km thick styrofoam is the elevator platform accelerated at 9.8m/s^2. stand on it. refer to my previous post and einstein. have a nice day. <br /><br /><br /><br /><br />

 

[spacechump]

<i>accelerated at 9.8m/s^2</i><br /><br />Relative to what? <br /><br />Edit: Hoorey! I'm miraculously a universe!

 

[bonzelite]

relative to the body being pushed, that was otherwise floating without pressure against itself from the styrofoam, acting as the elevator against the body (bottom of feet). <br /><br />gravity is a geometric effect of acceleration. mass is irrelevant. mass of styrofoam is far less than "earth." yet both can result in same 1g effect due to acceleration of a body upon their surfaces.

 

[spacechump]

<i>relative to the body being pushed, that was otherwise floating without pressure against itself from the styrofoam, acting as the elevator against the body (bottom of feet).<br /><br />gravity is a geometric effect of acceleration. mass is irrelevant. mass of styrofoam is far less than "earth." yet both can result in same 1g effect due to acceleration of a body upon their surfaces.</i><br /><br />But you're describing no mechanism for the acceleration!<br /><br />I feel you have a far misunderstanding of GR. The mass of the moon is much less then Earth and as a result gravitation acceleration at its surface is 1/6th that of Earth.<br /><br />The only way stryofoam could have the 1g gravitational acceleration of Earth is if there was a volume of stryofoam with a mass equal to earth. This is even calculatable with Newtonian physics. <br /><br />The truth is you're not making a whole lot of sense. The equivalence principal states that a constant acceleration and a mass can produce the same results, NOT that they are the same effect. More mass warps spacetime more; that objects are just following a steeper geometric gradient. A higher acceleration creates a stronger feeling of gravity due to an object being forced into another object. The the case of the elevator, energy is put into accelerating an elevator.

 

[bonzelite]

<font color="yellow">The only way stryofoam could have the 1g gravitational acceleration of Earth is if there was a volume of stryofoam with a mass equal to earth.</font><br /><br />the 1g accelerated styrofoam elevator is not the mass of the earth. yet the 1g effect will happen regardless upon said acceleration. blindfolded, the person either on earth or in the elevator will not be able to tell the difference. g is g. <br /><br /><i>einstein stated that the two forces are actually identical. the equivalence principle says that acceleration in space in one direction is equivalent to gravity pulling in opposite direction. </i><br /><br />g does not require mass. g is a result of acceleration.

 

[spacechump]

<i>the 1g accelerated styrofoam elevator is not the mass of the earth. yet the 1g effect will happen regardless upon said acceleration. blindfolded, the person either on earth or in the elevator will not be able to tell the difference. g is g.</i><br /><br />The styrofoam has to have energy imparted on it to accelerate it. A piece of styrofoam <i>can</i> cause me to feel a 1g acceleration...<i>if its being accelerated!</i>...lets say with a large rocket. I feel one gee here on Earth because its a big freakin' piece of rock! It's produces an equivocal force but not though the same mechanism as an acceleration. It's a geodesic effect of matter following spacetime's curvature.<br /><br /><i>g does not require mass. g is a result of acceleration.</i><br /><br />It's both.

 

[yevaud]

Equivalent: Noun, "qualities that are comparable."<br /><br />That's why Einstein referred to this using this word. They are not the same thing. <div class="Discussion_UserSignature"> <p><em>Differential Diagnosis:  </em>"<strong><em>I am both amused and annoyed that you think I should be less stubborn than you are</em></strong>."<br /> </p> </div>