EM Drive To Receive Peer Review

[JWPlatt]

Sees the very fast or the slow-mo?

DrCorby and Asbo Zaprudder have both pointed out the same issues with your apparent thinking. Either you are wording things badly, or you don't have the concepts correct. So I'm wondering if you could clarify what you are trying to say. A probe traveling at the speed of light (ignoring infinite mass) takes 4.367 years to reach Alpha Centauri from our frame of reference and zero time from the probe's (ignoring any other acceleration). Or in other words, we will be 4.367 years older than it upon its arrival there.

 

[Asbo Zaprudder]

Regarding acceleration, assume a 1000 kg probe (to allow for the inclusion of sufficiently large and long-lived power generating capacity in deep space) with a super-duper Em drive that can create a thrust of 100 mN. The acceleration a = F/m = 10^-4 m/s^2 so after one year the probe would be travelling at v = a.t = 3.1 km/s or 11,000 km/h. That's 0.001% of the speed of light and the speed increases linearly with time (and increasingly less so as relativistic effects kick in). It reaches 1% of c after 1000 years. Such a drive is just fine for the solar system but pretty crappy for anyone dreaming of exploring the nearby stars within current human life spans.

 

[psCargile]

Yes.

I'm wording it badly.

If I am on the probe nearing the speed of light, or approaching a blackhole, and I glance back at you, and you are, for the sake of argument, not moving, does your clock in relation to mine:

1) Move slower?
2) Move at the same rate?
3) Move faster?

 

[Dryson]

http://www.sciencealert.com/the-impossible-em-drive-is-about-to-be-tested-in-space

Times stops for the traveler, and I would suppose an observer on Earth would see that the trip took all the remaining time left in the universe.

The theories surrounding the What If's involving LST are not sound science and are even more whacked out than the EM Drive because everyone says the theories are correct but as to date no one has ever proven the theories correct other than on paper.

Time travelling and all of the hysteria surrounding close to LST, Light Speed Travel, is just that, insane semantical hysteria.

Time never stops for a person traveling at the speed of light or close to the speed of light. If time, or the measurable distance between two atoms interacting with each other in a medium that reacts with both atoms generating an energetic reaction did stop what you would have would be Primordial Space. Primordial Space where gravity, generated by suns, planets, black holes and other celestial objects not present before the Big Bang to effect a gravitational pull on atoms would not be present. Instead the force that would be present in Primordial Space, Time and Space before the Big Bang, would be Quantum and Sub-Quantum forms of energetic reactions. Interactions that possibly generated Quantum Gravity that maintain the quantum particle bonds between each other.

If you travel close to the speed of light or faster than the speed of light the fact is that Time is managed at various levels and is not dependent upon one level of time. Therefore no matter where you go or fast you travel through space time, time will always relative itself.

The factor that most confirm as time travel is based on how long a planet orbits a sun as well as other environmental factors. Since no one has every time traveled the basis for LST and time stopping and or time speeding up is not correct.

If someone on Earth traveled to Proxima Centauri at the speed of light which is 299,792,458 m/s or 299,792.458 km/s the person traveling from Earth will have aged 4.2 years when the probe arrives at Proxima Centauri b. Once the person from Earth steps foot on Proxima Centauri the factor of their representative age increases. Its takes Proxima Centauri b 11.186 days to complete a single revolution around its sun. It takes the Earth 365 days to complete one revolution around our sun.

A person from Earth makes the journey to Proxima Centauri at the age of 16. What will their age be on both planets?

If the 20.2 year old person from Earth stays for a single Earth based year,365 days,on Proxima Centauri, 32.630 years will have seemed to have passed on Earth, making the 20.2 year old a 52.830 year old Proxima Centaurian. Once the person returns to Earth however the 16 year old will actually have only aged 9.5 years, 4.2 years for the journey to Proxima Centauri and back to Earth and the additional year of staying on Proxima Centauri that would make the 16 year old only 25.5 years old on Earth based on calendar model of each planets number of times it takes to complete a single orbit around.

Depending on factors such as gravity and radiation immersion on Proxima Centauri would determine how the human appeared when they returned to Earth. The gravity and closeness to the Proxima Centauri sun might cause the human body to work harder thus increasing in age more rapidly than on Earth.

The 25.5 year old human might have aged to a 50 year old human compared to other 25.5 year old humans but on Earth the human would still be 25.5 years calendar wise with the body and possible natural ailments of a healthy 50 year old human who did the same type of work for year on Earth that the human did on Proxima Centauri.


A magnetosphere is the region of space surrounding an astronomical object in which charged particles are controlled by that object'smagnetic field.[1][2] The magnetic field near the surface of many astronomical objects resembles that of a dipole. The field lines farther away from the surface can be significantly distorted by the flow of electrically conducting plasma emitted from a nearby star (e.g. the solar wind from the Sun).

If plasma could be used in the EM Drive could field lines farther away from the surface be distorted to cause the flow of electricity to increase causing faster reaction times within the resonance cavity thus creating an even stronger potential for creating thrust and even a stronger thrust?

 

[sojourner]

 

[JWPlatt]

Yes.

I'm wording it badly.

If I am on the probe nearing the speed of light, or approaching a blackhole, and I glance back at you, and you are, for the sake of argument, not moving, does your clock in relation to mine:

1) Move slower?
2) Move at the same rate?
3) Move faster?

I'm looking forward to your selection on that.

 

[psCargile]

Everything I've ever read and watched about special relativity indicates faster, again from the perspective of the traveler.

 

[Asbo Zaprudder]

If I am on the probe nearing the speed of light and I glance back at you, and you are, for the sake of argument, not moving

Only relative motion is important and we can use Special Relativity if outside a gravity field (Earth's gravity will slow the clock very slightly as seen from further away from Earth; we can ignore this if the probe speed is high enough).

does your clock in relation to mine, appear to:
1) Move slower?

Yes. Both clocks counter intuitively appear to run slower as seen from the other frame of reference due to the relative motion. If you do the maths, however, the result of accelerating and decelerating means that if the clocks are brought back together, less time has elapsed on the clock that was accelerated and decelerated than on the one that stayed behind. It's quite a bit of a calculation to prove. Wikipedia has a non-technical explanation:
https://en.wikipedia.org/wiki/Twin_paradox

or approaching a black hole with you further away

We need to use General Relativity as Special Relativity assumes a flat space-time.

does your clock in relation to mine, appear to:
3) Move faster?

Yes. To the faraway observer, your clock appears to run slower.

 

[Dryson]

Everything I've ever read and watched about special relativity indicates faster, again from the perspective of the traveler.

Just because a traveler is moving faster does not mean they age faster. When traveling through space where planetary gravity is not present does a person actually age at all? Or is that aging process relative to a local planet of choice. Well not a choice rather because for the time being no one can choose what planet they are born on or at least have parents to make a choice for them which planet they are born on let alone conceived on which is the real determination of how you age.

If someone is born in space and not on a planet how do you determine their age?

 

[sojourner]

 

[psCargile]

Yes, the twin paradox. If I have a spacecraft that can fly at any sublight speed, I'm not concerned with how long my trip takes, I'm more concerned with what year it is when I get back. Was time dilation not portrayed correctly in "Interstellar" or in any of Alastair Reynold's hard sf, especially his "Revelation Space" novels? I believe it was. It matches what I've read in a Kip Thorne, Brian Greene, or Stephen Hawking book.

 

[Asbo Zaprudder]

Yes, the twin paradox. If I have a spacecraft that can fly at any sublight speed, I'm not concerned with how long my trip takes, I'm more concerned with what year it is when I get back. Was time dilation not portrayed correctly in "Interstellar" or in any of Alastair Reynold's hard sf, especially his "Revelation Space" novels? I believe it was. It matches what I've read in a Kip Thorne, Brian Greene, or Stephen Hawking book.

Kip Thorne helped to get Interstellar mostly correct (apart from one or two places where things were fudged a bit for the sake of the story). Alastair Reynold's Revelation Space series adheres to known physics for the most part apart from the unfortunate effect on causality when the Conjoiners attempt to make their drive FTL and the seemingly almost magical advanced superweapons. Both Thorne and Reynolds have PhD in physics and Thorne is renown for his work on General Relativity.

ETA: When you write "when I get back", you hit the nail on the head -- it's the choice of reference frames that causes the paradox. There is no universal now in Special Relativity -- only what you can deduce about distances and time intervals given your observations of comoving and distant rulers and clocks in a space time where light always travels at c (in vacuo).

 

[PurpleBuddha]

Just because a traveler is moving faster does not mean they age faster. When traveling through space where planetary gravity is not present does a person actually age at all? Or is that aging process relative to a local planet of choice. Well not a choice rather because for the time being no one can choose what planet they are born on or at least have parents to make a choice for them which planet they are born on let alone conceived on which is the real determination of how you age.

If someone is born in space and not on a planet how do you determine their age?

Time still passes in zero gravity. What exactly are you trying to say here? Also, if someone was born in space one year ago today, then they would be one year old right now. There, that wasn't so hard.

 

[JWPlatt]

Kip Thorne helped to get Interstellar mostly correct (apart from one or two places where things were fudged a bit for the sake of the story).

The metaphysical part about love transcending space and time was the absolute worst part of a good movie. Not as bad as finding satan in the black hole in Disney's The Black Hole, but close to it. But I'm sure Kip had nothing to do with the metaphysics of either.

 

[psCargile]

Zaprudder and Platt, I do understand time dilation in principle, I don't have the education to express it with eloquence. I understand it is a mess to sort out when everyone has their own clock and yardstick. This discussion made me go pull out Brian Greene's "The Fabric of the Cosmos: Space, Time, and the Texture of Reality" where he writes on page 448:

"When Einstein discovered the nature of special relativistic spacetime, he laid out a blueprint for fast-forwarding to the future. If you want to see what's happening on planet earth 1,000, or 10,000, or 10 million years in the future, the laws of Einsteinian physics tell you how to go about it. You build a vehicle whose speed can reach, say 99.9999999996 per cent of light speed. At full throttle, you head off into deep space for a day, or ten days, or a little over twenty-seven years according to your ship's clock, then abruptly turn around around and head back to earth, again at full throttle. On your return, 1,000, 10,0000, or 10 million years of earth time will have elapsed."

It is descriptions such as this that has lead me to think that "time dilation management" might be worth some consideration, but I concede that time dilation is negligible in the thought experience of an EM Drive to the Proxima Centauri, and admit that I have not considered the acceleration rate of the drive, or what percentage of light speed it will have attained two light years out. If, within the confines of the thought experiment, and the probe in question can reach fantastic speeds, I think it's reasonable to assume the launching agency of the probe wish to be the recipients of the data, not their grandchildren. That's all I'm saying.

If someone is born in space and not on a planet how do you determine their age?

You cut off a limb and count their rings.

 

[JWPlatt]

Just because a traveler is moving faster does not mean they age faster. When traveling through space where planetary gravity is not present does a person actually age at all? Or is that aging process relative to a local planet of choice. Well not a choice rather because for the time being no one can choose what planet they are born on or at least have parents to make a choice for them which planet they are born on let alone conceived on which is the real determination of how you age.

If someone is born in space and not on a planet how do you determine their age?

Someone whose name rhymes with Dysan and starts science topics ought to know these things.

A person always ages normally in their own frame of reference no matter the velocity, acceleration or equivalent gravity.

A person born in space uses the ship's on-board clock. But, you know, planets are in space, so that's where we are all born.

 

[JWPlatt]

Zaprudder and Platt, I do understand time dilation in principle, I don't have the education to express it with eloquence. I understand it is a mess to sort out when everyone has their own clock and yardstick. This discussion made me go pull out Brian Greene's "The Fabric of the Cosmos: Space, Time, and the Texture of Reality" where he writes on page 448:

"When Einstein discovered the nature of special relativistic spacetime, he laid out a blueprint for fast-forwarding to the future. If you want to see what's happening on planet earth 1,000, or 10,000, or 10 million years in the future, the laws of Einsteinian physics tell you how to go about it. You build a vehicle whose speed can reach, say 99.9999999996 per cent of light speed. At full throttle, you head off into deep space for a day, or ten days, or a little over twenty-seven years according to your ship's clock, then abruptly turn around around and head back to earth, again at full throttle. On your return, 1,000, 10,0000, or 10 million years of earth time will have elapsed."

It is descriptions such as this that has lead me to think that "time dilation management" might be worth some consideration, but I concede that time dilation is negligible in the thought experience of an EM Drive to the Proxima Centauri, and admit that I have not considered the acceleration rate of the drive, or what percentage of light speed it will have attained two light years out. If, within the confines of the thought experiment, and the probe in question can reach fantastic speeds, I think it's reasonable to assume the launching agency of the probe wish to be the recipients of the data, not their grandchildren. That's all I'm saying.

The amount of shipboard time that transpires for the 4.376 lightyear travel distance to Alpha Centauri will be next to nothing at .9... c - a minuscule part of a day. When observed from Earth, that same ship will appear to take slightly longer than 4.376 years. Traveling a day in your frame of reference at those speeds will take you far, far past Alpha Centauri.

Dilation is extremely helpful to the crew, assuming no other dangers, of which there are plenty.

 

[DrCorby]

It is descriptions such as this that has lead me to think that "time dilation management" might be worth some consideration, but I concede that time dilation is negligible in the thought experience of an EM Drive to the Proxima Centauri, and admit that I have not considered the acceleration rate of the drive, or what percentage of light speed it will have attained two light years out. If, within the confines of the thought experiment, and the probe in question can reach fantastic speeds, I think it's reasonable to assume the launching agency of the probe wish to be the recipients of the data, not their grandchildren. That's all I'm saying.

Yes, if the launching agency wants to get the data back in their lifetime, the faster the ship, the better. So using your hypothetical probe that can travel at fantastic speeds, you'd send it there and back at high speed. Say four-and-a-half years to Proxima Centauri, a year to explore, and another four-and-a-half years to return, traveling at near lightspeed. Those travel times listed are from the frame of reference of the folks staying on Earth.

Where time dilation comes into play is from the frame of reference of the probe passengers. If they quickly accelerate to near lightspeed and decelerate equally quickly, they'll spend most of the trip near lightspeed. And from their perspective, the trip would only take part of a day, as JWPlatt says. When they return to Earth, they would only be about a year older, from the time they spent exploring the Proxima Centauri system, at the same frame of reference as the folks on Earth, relatively speaking. So the time dilation is advantageous for the travelers, because the long, boring trip passes quickly for them, allowing them to still be young when they arrive to explore, and only a year older when they return to report. While their friends left behind on Earth have aged 9 years, since their frame of reference was never accelerated to near lightspeed. Win-win.

Larry Niven has played with this theme in some of his short stories and novels, like "The Ethics of Madness" and A World Out of Time, usually involving travel in Bussard ramscoops accelerating to high velocities.

 

[Asbo Zaprudder]

The most famous example of the twin paradox in SF literature is probably Joe Haldeman's The Forever War although there are lots of other examples.

 

[Dryson]

I forgot to add in the equation of comparing distance traveled by Earth in a year compared to the distance a light photon travels in a year.
In a single year the Earth travels 940 million kilometers.
A light photon travels at 299,792 km/s.

A light photon would take less time to travel the same distance that it would take Earth to complete a full revolution around the Sun.

Without doing the math I would have to say that light aging based on light speed travel would add an exponential age to someone traveling at the speed of light that would be compared to the distance of the photon traveling at light speed and the distance that the Earth travels in normal calendar year.
The traveler would be older based on light aging which you s based on a total distance crossed but would still be the same DNA age that they were when the left the Earth.