Weird Trick of Relativity Could Provide An Easy Way To Get High Relativistic Speed

The original work was done by one of the German pioneers ( David Hilbert) of Relativity theory. I believe he was a contemporary of Einstein. This later dude simply switched the reference frames. something perfectly permissible in relativity physics.

The trick can be accessed two ways. The first way requires your craft reach at least 3.5 percent C. While this is currently beyond our capabilities it soon will not be. the first intermittent fusion propulsion drives are about to be made at places like Washington University. these first drives will not do it either. but their successors will.

The second way does not require that type of starter speed. it involves a special pass by a gas giant planet or other similar mass. It's like a gravity assist in execution but the extra speed does not come from gravity generated acceleration in the way we normally mean. so this method should be usable now with current technological state of the art.

i think this could get a space craft to near light speed. The article doesn't really make clear what end of the relativistic regime it boosts a craft to so i am gonna go for the high end.

at .99 C a flight to alpha proxima would take about 4.3 years. whatever time it takes to explore and survey the system(s) and 4.3 years to come back home discounting deacceleration time. ideally there would be a relativity trick with the opposite effect on speed you could use to slow down. If it was an unmanned probe with no sample return requirements the trip could be done in 4.3 years plus mission dwell time on target.

www.technologyreview.com...

Felber has turned this idea on its head, predicting that a relativistic particle should also repel a stationary mass. He says that this effect could be exploited to propel an initially stationary mass to a good fraction of the speed of light.

The basis for Felber’s “hypervelocity propulsion” drive is that the repulsive effect allows a relativistic particle to deliver a specific impulse that is greater than its specific momentum, thereby achieving speeds greater than the driving particle’s speed. He says this is analogous to the elastic collision of a heavy mass with a much lighter, stationary mass, from which the lighter mass rebounds with about twice the speed of the heavy mass.

What’s more, Felber predicts that this speed can be achieved without generating the severe stresses that could damage a space vehicle or its occupants. That’s because the spacecraft follows a geodetic trajectory, in which the only stresses arise from tidal forces (although it’s not clear why those forces wouldn’t be substantial).

nextbigfuture.com...

The exact time-dependent gravitational-field solutions of Einstein’s equation in (Felber, 2008 and 2009) for a mass moving with constant velocity, and the two-step approach in (Felber, 2005b, 2006a, 2006b and 2006c) to calculating exact orbits in dynamic fields, and the retarded fields calculated in (Felber, 2005a) all give the same result: Even weak gravitational fields of moving masses are repulsive in the forward and backward directions at source speeds greater than 31/2 c .

reply to post by stormbringer1701


Hello.

Many people think about how to go faster in relativistic space.
This is good.

That, however, is only half of problem.
Where is the brakes?
How to stop?

Fast is good, but, how to stop once the destination is reached?

Another problem: time dilation.

Traveling at 0.99 c both ways result's in a trip of only 8.6 years for the probe.

But over 60 years will have passed here.

eriktheawful
Another problem: time dilation.

Traveling at 0.99 c both ways result's in a trip of only 8.6 years for the probe.

But over 60 years will have passed here.

I believe your understanding of time dilation is incorrect. at .99 c those outside the ship will see the journey take 4.3 years but those inside the ship will experience only a few weeks. those at rest relative to the ship (here planetary orbital speed and stellar orbital speed around the galaxy are ignored) have no time dilation effect good or bad.

reply to post by stormbringer1701

I'd love to see the results of the test at the LHC. So it would be a special kind of ion drive?

reply to post by stormbringer1701

Yes something like that. The relativistic change factor is 7.088812050083354 at .99 c so a little over a year would pass inside the ship in an 8.2 light year round trip, if you traveled constantly at .99c.

reply to post by KonstantinaValentina

In an 4 year journey, you can spend 2 years accelerating and 2 years decelerating.

KonstantinaValentina
reply to post by stormbringer1701

 

Hello.

Many people think about how to go faster in relativistic space.
This is good.

That, however, is only half of problem.
Where is the brakes?
How to stop?

Fast is good, but, how to stop once the destination is reached?

edit on 10-3-2014 by KonstantinaValentina because: (no reason given)

braking is indeed a very important consideration. firstly it means up to half of your trip must be spent de-accelerating. secondly it means increased fuel must be carried to power the de-acceleration. and it plays havok with other consumables like food water and air and even cleaning supplies and other things you wouldn't think of. This is because the benefit of time dilation is lost rapidly as you slow below .99c so you would then consume stuff for longer in the reference frame of the ship than if they were going at .99 all the way.

but I hope for a complimentary relativity trick to remove the extra velocity. it would take a physicist to determine if there is such a trick available to slow down. if not:

one way to slow down for cheap is to use a M2P2 mini magnetospheric plasma sail to use the targeted stars solar wind to slow down. they are lightweight (about the size of a coffee can for each lobe of the sail, require relatively little plasma source gases to work and little power. if one pass would not do it you could enter a large orbit and run the sail when going towards the star for each orbit and shut it off on the outbound portion of the orbit. the sail is self inflating and scoops up ambient ions to feed the expansion and help fight inevitable loss of ions through leakage of the magnetic field. they can be inflated to huge sized up to 100 KM diameter maybe even bigger.

Arbitrageur

I'd love to see the results of the test at the LHC. So it would be a special kind of ion drive?

the article is from 2009. i do not know if the experiment was done. i would assume not since i have seen no follow ups but i will search for it later today.

EDIT: it may been done though because i found this article when trying to find one about a similar effect that is actually newer than this set of articles in the OP. i wanted to share that one but could not find it. but it is possible the article i was looking for was a follow up to this.

method one would appear to be an ion drive. instance two is whatever you want to use.

the way i would do version one is with a cage of particle accelerators around the fusion engine. the odd thing is i think your ion beams would be facing towards the front (shooting in the direction of travel.) though he may have meant some sort of launch rail or tunnel if you can't self bootstrap like i would want to do to avoid needing a huge infrastructure at either end of a trip.

stormbringer1701

eriktheawful
Another problem: time dilation.

Traveling at 0.99 c both ways result's in a trip of only 8.6 years for the probe.

But over 60 years will have passed here.

I believe your understanding of time dilation is incorrect. at .99 c those outside the ship will see the journey take 4.3 years but those inside the ship will experience only a few weeks. those at rest relative to the ship (here planetary orbital speed and stellar orbital speed around the galaxy are ignored) have no time dilation effect good or bad.

Time Dilation due to velocity is given as:



Where:

t prime = amount of time passing for the observer at rest (IE us here on Earth).
t = amount of time passing on the ship moving
v = ship's velocity
c = speed of light.

If the distance to your destination is 4.3 lightyears, traveling at close to light speed (99%), the travel time for anyone on board the ship will be around 4.3 years.

In the above expression, you can use m/s , km/s , miles /s or even percentages to represent the velocity of the ship and light (as long as you use the same for both).

So we punch in our numbers:

t prime = ?
t (ship time) = 4.3 years
v = 0.99
c = 1

v squared is 0.9801
c squared is 1.0

v/c = 0.9801

1 - 0.9801 = 0.0199

The squareroot of 0.0199 = 0.14106735979665884425232163690877

4.3 / 0.14106735979665884425232163690877 = 30.481891815358443732913720538077

So, 4.3 years ship time, traveling at 99% of the speed of light equals 30.48 years for those observers at rest (here on Earth).

Time Dilation Wikipedia

reply to post by eriktheawful


The trend here seems to ignore that an incredible amount of time will be required to accelerate the velocity of the ship from zero to .99SOL. At the midway point the ship would have to reverse the direction of the thrusters and light them up for the exact same amount of time to deliver the ship to zero speed once the reached the other star. There ain't no free lunch, so factor that in also.

Better shelve all of this relativistic chatter and copy the very manner that UFOs seem to move and that is by canceling their mass. Do that, and you can fly alongside protons. I know textbooks and professors must keep you ignorant of what seems to be the most likely possibility of genuine interstellar travel, but all of you young, bright minds should be considering alternatives that are literally staring you right in the face.

eriktheawful

stormbringer1701

eriktheawful
Another problem: time dilation.

Traveling at 0.99 c both ways result's in a trip of only 8.6 years for the probe.

But over 60 years will have passed here.

I believe your understanding of time dilation is incorrect. at .99 c those outside the ship will see the journey take 4.3 years but those inside the ship will experience only a few weeks. those at rest relative to the ship (here planetary orbital speed and stellar orbital speed around the galaxy are ignored) have no time dilation effect good or bad.

Time Dilation due to velocity is given as:

Where:

t prime = amount of time passing for the observer at rest (IE us here on Earth).
t = amount of time passing on the ship moving
v = ship's velocity
c = speed of light.

If the distance to your destination is 4.3 lightyears, traveling at close to light speed (99%), the travel time for anyone on board the ship will be around 4.3 years.

In the above expression, you can use m/s , km/s , miles /s or even percentages to represent the velocity of the ship and light (as long as you use the same for both).

So we punch in our numbers:

t prime = ?
t (ship time) = 4.3 years
v = 0.99
c = 1

v squared is 0.9801
c squared is 1.0

v/c = 0.9801

1 - 0.9801 = 0.0199

The squareroot of 0.0199 = 0.14106735979665884425232163690877

4.3 / 0.14106735979665884425232163690877 = 30.481891815358443732913720538077

So, 4.3 years ship time, traveling at 99% of the speed of light equals 30.48 years for those observers at rest (here on Earth).

Time Dilation Wikipedia

you are applying the calculation to the wrong reference frame. there is no way a stationary observers time is longer than the natural time it takes to observe light going to the same place. it is the accelerated frame that experiences time dilation. i will say it again. for stationary observers the trip takes 4.3 years. for those inside the accelerated frame in the craft time is contracted and the trip seems to take a lot less time than it should.

reply to post by Aliensun


ufo's Yeh right!

Aliensun
reply to post by eriktheawful

 

The trend here seems to ignore that an incredible amount of time will be required to accelerate the velocity of the ship from zero to .99SOL. At the midway point the ship would have to reverse the direction of the thrusters and light them up for the exact same amount of time to deliver the ship to zero speed once the reached the other star. There ain't no free lunch, so factor that in also.

Better shelve all of this relativistic chatter and copy the very manner that UFOs seem to move and that is by canceling their mass. Do that, and you can fly alongside protons. I know textbooks and professors must keep you ignorant of what seems to be the most likely possibility of genuine interstellar travel, but all of you young, bright minds should be considering alternatives that are literally staring you right in the face.

by incredible you mean just under a year?

for manned missions there is actually good reason to want to spend half your time accelerating and the other half de-accelerating.
if you spend months at constant velocity you will need some form of artificial gravity. otherwise you will be in no condition for away missions at the destination and you will not be able to re-acclimatize to normal gravity upon return to earth. chances are it will kill you. on the other hand if your dwell time on orbit at the destination is long enough you will have the same problem. absent some form of grand unified field derived electronic gravity you will need a spinning habitat module. this adds complexity, critical failure points, greater power requirements and mass to your craft.

you could accelerate and deaccelerate at 1g in ayear on either end of the trip but you would then spend most of the trip without the benefit of acceleration induced "gravity."

on the other hand if you take advantage of this relativity trick your acceleration will be nearly instant. you would actually spend most of the trip (4 plus years minus about 3 or 4 months) without gravity (assuming you elected for 1 G de-acceleration at the end) unless you had a rotating habitat. or you could de-accelerate for half the journey anyway but you could not do it at one G in that case. maybe around 1/2th G. might as well opt for a centrifuge module and make (at least part of) your ship 102 meters in diameter minimum.

I wonder how many times you could use this trick before you significantly decreased it's rotational speed or even affected it's orbit. energy is conserved. to gain that energy Jupiter has to lose it. at least I am pretty sure that would be the case. but i do not know how to calculate the energy involved.

reply to post by stormbringer1701


Time is not slowing down for the observer outside the reference of the ship (IE at rest here on Earth).

Time is slowing down for those on the ship.

If I build a ship that goes let us say 500,000 Mph, it will take about 1,342 years to travel 4.3 light years. 500,000 Mph is about 0.0746 % of the speed of light. Relativistic effects are very minimal at this point. Ship time and Earth time will stay close to each other.

However, as the ship accelerates, relativistic effects on board the ship begin to happen.

The following table illustrates how insignificant the effect of time dilation are for velocities as great as half the speed of light, but how dramatic it becomes as you draw ever closer to the speed of light. For each velocity, the time which elapses in the rest frame for each day measured by the ship's clock is given. By the time we reach 90% of the speed of light, for each day on board, two and a quarter days pass for an observer stationary with the respect to the Lattice. As we start tacking on nines to our velocity, time dilation becomes ever more extreme. At 0.999999 of the speed of light, almost two years pass in the Lattice for every ship's day. If we continue to accelerate to 0.99999999999999 c, for every day on board, nearly twenty thousand years pass for the observer at rest.

At the velocities people currently travel the effect of time dilation is small, but measurable with accurate instruments. Since time dilation affects the rate at which time passes, the total discrepancy between stationary and moving clocks increases throughout the voyage. Several Russian cosmonauts have spent a year or more in Earth orbit on the space station Mir. Their orbital velocity, about 7700 metres per second, is only 0.0000257 times the speed of light, yielding a time dilation factor of 1.00000000033; each second on board Mir, 1.00000000033 seconds pass on Earth. For every second you age on Earth, the cosmonaut in orbit ages 3 nanoseconds less. This doesn't seem like much, but it adds up; after a year the cosmonaut's watch will be 3.8 seconds behind your earthbound timepiece.

Source

Again: time is slowing down for the ship, not people here on Earth.

In order for people or instruments to get to Alpha Centauri in 4.3 years (travel time for THEM that they experience), they will have to accelerate to 0.99% the speed of light or faster.

Once they do that, to them, the trip only took 4.3 years. But for those of us at rest here on Earth, it will appear to us that the trip took over 30 years for them to get there.

When traveling close to the speed of light, those on board a ship doing so will not arrive at Alpha Centauri in only a mater of "weeks" their time. In order to do so, they would need a FTL ship.

Consider a space ship traveling from Earth to the nearest star system outside of our solar system: a distance d = 4 light years away, at a speed v = 0.8c (i.e., 80 percent of the speed of light).
(To make the numbers easy, the ship is assumed to attain its full speed immediately upon departure—actually it would take close to a year accelerating at 1 g to get up to speed.)
The parties will observe the situation as follows:[5][6]
The Earth-based mission control reasons about the journey this way: the round trip will take t = 2d/v = 10 years in Earth time (i.e. everybody on Earth will be 10 years older when the ship returns). The amount of time as measured on the ship's clocks and the aging of the travelers during their trip will be reduced by the factor epsilon = sqrt[1 - v^2/c^2], the reciprocal of the Lorentz factor. In this case ε = 0.6 and the travelers will have aged only 0.6 × 10 = 6 years when they return.
The ship's crew members also calculate the particulars of their trip from their perspective. They know that the distant star system and the Earth are moving relative to the ship at speed v during the trip. In their rest frame the distance between the Earth and the star system is εd = 0.6d = 2.4 light years (length contraction), for both the outward and return journeys. Each half of the journey takes 2.4/v = 3 years, and the round trip takes 2 × 3 = 6 years. Their calculations show that they will arrive home having aged 6 years. The travelers' final calculation is in complete agreement with the calculations of those on Earth, though they experience the trip quite differently from those who stay at home.

Twin Paradox

I don't know how to make it any simpler than: time slows down for those aboard the ship.

One thing, why come back? if there is something that can be used for fuel for the ion drives, why not go on to the next star? if there is water ice and mineral asteroids to mine, just keep going, frozen animal sperm and eggs for meat, hydroponics for fruit and veg., plus a large store of seeds, just send back radio or laser signals, or message drones.

you said that the observers on the planet saw the travel time of the ship take 60 years or something to that effect. that is the same as saying the distance magically changes from 4.3 LY to 60 LY for people who are not doing anything special. because if the ship takes 60 years from the stationary point of view then so would a photon (roughly.)

time passes normally at home but from the crew's perspective it takes less time.

pikestaff
One thing, why come back? if there is something that can be used for fuel for the ion drives, why not go on to the next star? if there is water ice and mineral asteroids to mine, just keep going, frozen animal sperm and eggs for meat, hydroponics for fruit and veg., plus a large store of seeds, just send back radio or laser signals, or message drones.

take the case of the Centauri system. we would indeed go on to the next star and then the next. they are roughly in a straight line and about a tenth of a light year (or just slightly more) apart. all three could have planets in the life zone and two of them are near matches for Sol even though one is a K type. a K type is really not that different from a G type like sol or rigil kentaurus.

but beyond that there are no other stars that don't require longer than the original trip after that. if we had FTL then we could turn on to Barnard's star and then go on to wolf 359 and the two brown dwarfs at that same basic range. but without FTL; Barnard's star and the others would require separate missions and probes or manned vehicles.

right now we do not know if there is a a class m planet with the proper conditions to support our type of life. therefore one has to assume a trip home if humans precede probes or astronomical verification of a place to go.



EDIT: if you go to www.solstation.com... you will see the relative positions and distances of stars within ten light years. though several stars are within 6 or so light years with the exceptions of the triple system of proxima, rigil (or alpha) kentaurus and AC b there is no other trip that can hit more than two stars in a reasonable amount of time at sublight speed. there are a couple of binary systems and a binary set of brown dwarfs. there are some where you could only hit one star.

reply to post by stormbringer1701



Forget what I said.....doh! You are correct.

Not enough coffee this morning I guess: yes, time slows down for the crew, but only 4.3 years will have passed here (one way).

I must be sort of half way in my own time dilation this morning.

eriktheawful
reply to post by stormbringer1701

 

Forget what I said.....doh! You are correct.

Not enough coffee this morning I guess: yes, time slows down for the crew, but only 4.3 years will have passed here (one way).

I must be sort of half way in my own time dilation this morning.

you were not alone. and i almost doubted myself even though i have known how time dilation works in that regard for decades Minus the math. though i did not know until recently that it was the equivalent of time travel under some circumstances.