Random Thought about space travel.

[Drunkskunk]

Not bike related, but Most of you folks are geniuses, so this might be a fun thought exersize.

If you could build a spaceship that could travel at 0.1C, or one tenth the speed of light, Would you still be able to see your controlls in the cockpit? would you be able to see the rear of the cockpit?

Since light travels at a constant speed regardless of how fast the source is moving, wouldn't there be enough dopler shift at 0.1C to cause light to shift out of the visable range? And wouldn't it shift in 2 directions? The light from Things in front of you inside the ship shifting down past infrared and behind you going up past ultra violet?

My theory is that if you could fly a ship fast enough, the crew would be effectivly blind.



I've been working on a novel for years, and this idea came up when I was trying to reason out what it would be like to go that fast.

 

[www.recumbents.com]

I have been thinking about this too much lately. Is there an "absolute zero" speed in space, or are all speeds relative to something else? If all speeds are relative to something else, why would speed be limited by the speed of light? I have to ask my sister, the Physics teacher.

Now they are saying that hydrogen cannot survive if it goes faster than .5C because it heats up the closer it gets to lightspeed. Doh!

-Warren.

 

[Dauntless]

Knew little of this when I DID remember, but:

1) The laws of physics include changing the application at higher speeds. Something like 0.3 of the speed of light is supposed to be a whole new rulebook we're not familiar with.

2) Those Earthbound think of physics as Newton, space travellers think of physics as Einstein.

3) . . . .Oh, wait, you're not supposed to learn that part yet.

 

[csmarr]

Everything inside the ship would appear normal. If you measured the speed of light in the ship it would be the same as when the ship was at rest before takeoff. When looking outside the ship the rest of the universe would appear to be skewed. At 0.1C the distortion would be minimal. At higher speeds like 0.99C there would be an obvious distortion, The stuff in front of you, outside the ship, toward which you are traveling would be blue shifted and the stuff behind you would be red shifted. They would also seem to be shifted closer together both in front of you and behind.
Browse around http://www.projectrho.com/public_html/rocket/index.php. It is a science fiction minded physics site and has a lot of scenarios, gizmos and spaceships.

 

[Joseph C.]

Photonic Boom!

http://en.wikipedia.org/wiki/Cherenkov_radiation

 

[Dauntless]

At higher speeds like 0.99C there would be an obvious distortion, The stuff in front of you, outside the ship, toward which you are traveling would be blue shifted and the stuff behind you would be red shifted. They would also seem to be shifted closer together both in front of you and behind.

You forgot the Starbow.

http://www.osa-opn.org/home/articles/volume_20/issue_4/departments/light_touch/a_brief_history_of_the_starbow/ (Gotta subscribe, but you might like it.)

Pohl’s starbow image made for an interesting cover to the issue of Analog in which his story first appeared. But did it represent accurate physics?

Physics of the starbow

The German scientist Ing E. Sänger of Germany may have been the first to consider the effects of relativity on an observed star field. He assumed, for simplicity’s sake, that each star could be considered as a yellow monochromatic source at, say, 5,900 Å. This approach allowed him to easily calculate the color shift from the known relativistic Doppler shift associated with the ship’s velocity ν:

“Thus, with all Einstein numbers of flight [ν/c] greater than 0.37, a major dark spot will surround the take-off star, and a minor dark spot the target star. Between the two limiting circles of these spots, all stars visible in the sky are colored in all the hues of the rainbow, in circles concentric to the flight direction, starting in front with violet, and continuing over the blue, green, yellow and orange to red at the other end.”

Intrigued by Pohl’s story, scientists Paul Doherty and John M. McKinley of Oakland University in Rochester, Mich., U.S.A., tried plotting it. When they calculated the effects of relativistic contraction, they didn’t see at all what Sänger had described. There was no completely UV-shifted “dark disc” in front, nor a completely IR-shifted “dark disc” around the departure star. Moreover, the space between was not filled with the expected spectrum of stars.

What was different between the two sets of calculations?

http://cartan.e-moka.net/content/download/248/1479/file/Astronave%20relativistica.pdf

Keep in mind this is all theoretical. In fact an absolute guess on the part of a lot of people who could someday see just how far off they were and say "Boy, do I feel silly getting my life's work all wrong."

 

[Philistine]

Maybe I am totally missing something, but isn't the point that your controls (along with all matter between you and the controls) are moving at the same speed (ie the whole vehicle - including you - and everything in it is moving at the same speed, so to you everything inside your vehicle/craft would look totally normal, and it is only when you look out the window that you start wondering if someone dropped some acid in your breakfast....

EDIT: Sorry, just read Csmarr's post then, I posted after reading the first two or three posts....

Time as a concept has always broken my brain. I still struggle with time itself as a concept, both in physics and metaphysics.

 

[liveforphysics]

Time as a concept has always broken my brain. I still struggle with time itself as a concept, both in physics and metaphysics.

Glad to hear the Phil. The reason time has broken your brain, is because time isn't real, never has been real, and never will be real. It's merely an artifact of human perception limitations. A massive in-common group delusion, like boarders between countries, property concepts, human laws, etc.

Time is like if a 2d being was traveling through our world, the infinitely thin slice of the 3'rd dimension he requires to have his perception of reality exist looks like a sheet of paper to us, but it's time to him (where it's obviously just the 3rd dimension to us). It's no different in our 3rd world thinking our infinitely thin slice of perception capability of the 4th dimension is some flow of the imaginary human construct time rather than the infinitely thin slice of the 4th dimension we require to have our 3 dimensions of perception.

 

[Arlo1]

Time as a concept has always broken my brain. I still struggle with time itself as a concept, both in physics and metaphysics.

Glad to hear the Phil. The reason time has broken your brain, is because time isn't real, never has been real, and never will be real. It's merely an artifact of human perception limitations. A massive in-common group delusion, like boarders between countries, property concepts, human laws, etc.

Time is like if a 2d being was traveling through our world, the infinitely thin slice of the 3'rd dimension he requires to have his perception of reality exist looks like a sheet of paper to us, but it's time to him (where it's obviously just the 3rd dimension to us). It's no different in our 3rd world thinking our infinitely thin slice of perception capability of the 4th dimension is some flow of the imaginary human construct time rather than the infinitely thin slice of the 4th dimension we require to have our 3 dimensions of perception.

 

[amberwolf]

Since light travels at a constant speed regardless of how fast the source is moving, wouldn't there be enough dopler shift at 0.1C to cause light to shift out of the visable range? And wouldn't it shift in 2 directions? The light from Things in front of you inside the ship shifting down past infrared and behind you going up past ultra violet?

As has already been pointed out with the starbow, light from outside the ship would indeed (probably) look like that, but inside the ship the reference frame is all the same, so it would look just like always.

I don't pretend to understand the math, but
http://en.wikipedia.org/wiki/Theory_of_relativity
and
http://en.wikipedia.org/wiki/Time_dilation
may help you understand better; there are some good shows on Nova / Horizon that explain it in layman's terms much better (although I can't recall their titles).

I've been working on a novel for years, and this idea came up when I was trying to reason out what it would be like to go that fast.

Just curious: how much other science fiction have you read, from which authors? (I'm guessing you havent' ever read Fredrick Pohl's "The Gold at the End of the Starbow", or another one by Pohl Anderson "Tau Zero")

(edit: I somehow missed Dauntless' post about the starbow--i'll have to go read that pdf when I am not so tired)

OT: FP's story brougth something to mind, which oddly I instantly found summarized quite well here:
http://lizard-sf.xanga.com/weblog/?uni-22-direction=n&uni-22-nextdate=12%2F21%2F2005+15%3A32%3A25.080
in the first hit on google when I looked for someone talking about it so you wouldnt' have to read *my* rambly thougths on it.)



Probably seems strange or even silly, but most of the science I know came from reading science fiction (starting with stuff as old as Jules Verne and workign my way thru newer and newer stuff, ridiculously bad and incredibly good, thru the 80s and a little in the 90s, when I simply ran out of time to read any more. ) But it gave me a basis to understand when I found (or sought out) "real" science information, and taught me the basis of science itself, whcih is that everything can be called into question (indeed, it *should* be!), and can probably always be refined or redefined as we learn more...enabling us to make new tools to learn more to make new tools to learn more to....

Meaning: maybe the theories are wrong, and the light energy is not relative to the framework it is emitted in, and the astronauts would indeed be unable to see. But if this is true, it also means that all other forms of electromagnetic radiation, like the heat generated by their bodies, would also be shifted upward in spectrum, so that they would eventuallly be killed by the differential in energies within their own bodies.

Physics itself wouldnt' really work like you expect it to, and nothing would operate correctly, because anything forward of something on the ship would be at a higher energy state than anything behind it, including individual atoms or subatomic particles. Electrons at some point could no longer orbit protons, becuase the energy required to go "forward" again after completing half an orbit would be higher than that of the entire universe, becuase it would have to go faster than light to do it. It all gets really confusing to think about here, so I will stop hurting my brain.

 

[whatever]

a bit off topic but I"ve been thinking about the possibility of a cheap way to get into space.
After seeing the recent balloon jump from 39km ( there is another guy going up in a rocket to try beat the new freefall record soon) I've come up with this scenario for exiting earth gravity which would be cheap but hard to build
1. a balloon such as the redbull jump filled with hydrogen ( a bit dangerous I know.......no smoking allowed during ascent!)
2. once the balloon reaches equilibrium height its necessary to vent gas as the balloon continues to expand, balloon has reached fully extended shape
3. vented gas ( hydrogen: h2 ) is vented via rocket type nossle as base of balloon
4. exit point of H2 nossle the H2 is broken up into two H ions ( using solar energy) they recombine giving off plasma flame and provide thrust

This means the large amount of H2 in the balloon acts as a fuel ( no oxygen needed), since the rocket stage doesn't start till about 40km, there is minimal drag from atmosphere ( probably negligible), so the whole balloon acts as a rocket ( no aerodynamics to worry about)

The problem is how to collect the solar energy into a intense concentration to split the H2 into two ions ( which will naturally recombine giving off energy as plasma and light). There are some balloons which have a solar concentrator built into them, the parabolic mylar concentrator takes it shape when balloon is fully blown up. At the focus you would need to transfer the high flux solar energy to the exit nossle via optic fibre.

How to orientate the parabolic reflector to face the sun is a big problem. Anyhow just thought I would put it out there.
Probably a better option is for the outer fabric of the balloon to act as a light guide to collect the solar energy, quite a big problem how to collect it.
I think its quite possible to use this method for propulsion. Whilst searching the topic some time ago it seems that nasa has been working on a similar type
of propulsion system since the 90s
Irving Langmuir worked out h2 can be split and recombined way back in 1920's he made a plasma cutter/welder using the principle

 

[flathill]

You can only travel as fast as you want when you have no structure
Gravity is just ultrafluid flow
Reality is the fluid
And it As real as life and death
But you never die if your wave has been heard
Structure is just vortex fractals
Look up h3 vortex and space plasma double helix to understand
Then study sound

 

[www.recumbents.com]

My sister explains it:

So, Einstein's special relativity theory says that no matter how fast you're moving (with respect to anything else - like with respect to the object that gave off the light), when you measure the speed of light, you always get the same answer. (This has been shown to be true experimentally.) This implies that there is no "absolute zero" speed that all other speeds are compared to. All that matters is the relative speed between two different people (or "spaceships", or "reference frames"). So, when you think about adding speeds together at "normal speeds", you get "normal behavior" - like, one car drives down the highway at 50 mph to the East and an second car drives down the highway at 60 mph to the West. From the first car, it looks like the second car is moving away at 110 mph. When the speeds of objects are close to the speed of light, they don't add "normally" anymore (the "normal" speed addition is really just a slow speed approximation). So, if one spaceship is going "East" at 0.5 C and another spaceship is going "West" at 0.6 C, the second spaceship is not moving 1.1 C with respect to the first, but, according to the correct equation, is going 0.85 C with respect to the first. The intuition that we've developed at slow relative speeds does not work at relative speeds near C. The constant speed of light has other implications, like time changing differently in different reference frames (leading to the "twin paradox").

Simple, Eh?

-Warren.

 

[itchynackers]

Yes, well done.
Also, if you've watched any of Carl Sagans shows, he explains that if an alien is 100 light years away from us, then pedals his bicycle away from us, he will see our future as though it already happened (he is looking through a telescope). And if he pedals toward us, he will see our past. From that I've concluded that we indeed do NOT have free will, and what we have done, and will ever do, is already pre-determined. Fate is sealed. Sorry to be a bummer.

 

[Joseph C.]

Yes, well done.
Also, if you've watched any of Carl Sagans shows, he explains that if an alien is 100 light years away from us, then pedals his bicycle away from us, he will see our future as though it already happened (he is looking through a telescope). And if he pedals toward us, he will see our past. From that I've concluded that we indeed do NOT have free will, and what we have done, and will ever do, is already pre-determined. Fate is sealed. Sorry to be a bummer.

I don't get it at all - although I'm trying.

So we have an observer 100 light years away from Earth with a telescope. And he is looking at the Earth 100 years in the past.

I comprehend as far as there however what follows doesn't make sense to me. My understanding would be that it doesn't matter where he moves unless he can get there superliminally.

 

[flathill]

An international team of researchers, from Russia, Germany, and Australia, suggest from their study that when electrically charged interstellar dust particles (those in plasma, the fourth state of matter) are in a microgravity environment of space (***commonly called zero gravity***) they are attracted to each other. Thus, they join together in a string-like configuration and then twist themselves into spiral (corkscrew-like) shapes.

DNA is deoxyribonucleic acid, the substance that carries an organism's genetic information. Plasma is the fourth state of matter (the other three being gas, liquid, solid), which is ionized gas, such as what is found in stars.

The shape was held together by electromagnetic forces. It appeared to the scientists that the group of dust particles could reproduce, transferring the information acquired as to its helix shape into the next generation.
----------------------

For a better understanding about time dilation you just need to understand Precession:
gyroscopes are not just toys but you don't really learn about them in school because school sucks and never allows time for you to become competent in one subject matter as you must learn more than one subject per day rather than allowing you to become competent during the short time you are obsessed until you get bored. Maybe I want to spend the next 3 months only studying gyroscope or only learning Sanskrit. School is the problem not the answer. Life experience will lead you on a path

http://einstein.stanford.edu/
http://einstein.stanford.edu/

 

[cal3thousand]

Yes, well done.
Also, if you've watched any of Carl Sagans shows, he explains that if an alien is 100 light years away from us, then pedals his bicycle away from us, he will see our future as though it already happened (he is looking through a telescope). And if he pedals toward us, he will see our past. From that I've concluded that we indeed do NOT have free will, and what we have done, and will ever do, is already pre-determined. Fate is sealed. Sorry to be a bummer.

Just because he sees our future, doesn't mean it is already set. It just means that by the time it happens, he will be sufficiently far enough to see the photons of light that describe the event in question.

A space alien sufficiently far (and with a sufficiently powerful telescope), could theoretically see what was here in our "spot in space" before Earth was actually here. But he can't tell us what is going to happen because the photons that describe that picture have not even headed towards space, because they haven't been reflected, since the events have not occurred.

 

[Philistine]

Also, if you've watched any of Carl Sagans shows, he explains that if an alien is 100 light years away from us, then pedals his bicycle away from us, he will see our future as though it already happened (he is looking through a telescope). And if he pedals toward us, he will see our past. From that I've concluded that we indeed do NOT have free will, and what we have done, and will ever do, is already pre-determined. Fate is sealed. Sorry to be a bummer.

That is actually not an argument in support of fatalism. It does not deductively follow from the fact that the alien can see a future state of events that the future state of events were necessary. There are two elements needed to prove fatalism (and disprove or negate free will), a determinate physical universe (ie things either exist or don't exist they can't exist and not exist simultaneously, and they can't exist in two different places at the same time) which operates purely according to causation and the inability for there to be unconditioned causes/events (ie things can't just physically happen for no reason at all).

Whilst both those conditions appear intuitively true, the problem is that quantum physics and apparent phenomena like quantum entanglement suggest there is support for the possibility to break those seemingly intuitive rules, thus free will is in fact possible (or at least strong evidence supports it), or the possibility of things like the multiverse.

 

[Dauntless]

Also, if you've watched any of Carl Sagans shows, he explains that if an alien is 100 light years away from us, then pedals his bicycle away from us, he will see our future as though it already happened (he is looking through a telescope). And if he pedals toward us, he will see our past. From that I've concluded that we indeed do NOT have free will, and what we have done, and will ever do, is already pre-determined. Fate is sealed. Sorry to be a bummer.

Didn't see it, I assume Sagan was speaking metaphorically. You can't see what doesn't exist, our future does not exist any more than the 2020 model year cars exist. (DON'T say there are drawings.) Rather than looking at Carl Sagan as philosphy I look at it as infotainment. Searched and searched without finding that as a quote from Sagan. Sure did find some interesting theories on what Sagan meant by OTHER things he said.

Q: How many Carl Sagans does it take to screw in a light bulb?
A: Billions and billions, made of star stuff.

Q: How many Zen masters does it take to screw in a light bulb?
A': Two: one to change the bulb and one not to change it.
A": One to change and one not to change is fake Zen. The true Zen
answer is Four. One of whom changes the bulb. Focus on the one
changing the lightbulb, not on what the others are doing at that moment.

We live in a society exquisitely dependent on science and technology, in which hardly anyone knows anything about science and technology.
-Carl Sagan

 

[amberwolf]

We live in a society exquisitely dependent on science and technology, in which hardly anyone knows anything about science and technology.
-Carl Sagan

A phrase proven daily, even here on ES.

 

[itchynackers]

As he moves toward/away from us, what he "sees" will shift (into the past and into the future). It may have been 100,000,000 light years.

 

[Joseph C.]

As he moves toward/away from us, what he "sees" will shift (into the past and into the future). It may have been 100,000,000 light years.

Yes but only if the observer can move faster than light and that only works in one direction.

If the telescope viewer is 100,000,000 light years and moves towards the planet at a rate faster than the speed of light - he can travel back in time. Let's say he can travel at 2c and he spends 99,999,999 years travelling towards the planet at twice the speed of light - in theory he could arrive there nearly 200,000,000 years previous to his original viewpoint. Looking through his telescope now one light year away from the planet would be the same as looking at the planet 200,000,000 years in the past rather than just half that time when he was 100,000,000 light years away.

I don't think it works the other way though. I don't think you can travel into the future even if you could travel faster than the speed of light.

Edit: Actually thinking about it again - if you could travel faster than the speed of light in theory you could just travel farther and farther (although in this context that could also be further and further) away from the planet. Therefore, you could look at earlier and earlier light detailing earlier and earlier events - through this telescope.

Although really that's not the same as travelling back in time as all you are doing is looking at earlier 'broadcasts' of events that occurred on that planet. Whereas if you travel towards the planet faster than the speed of light in the scenario outlined above you are physically travelling backwards in time.

However, doesn't light (apart from laser) diffuse as it travels away from its source. Therefore, a telescope that could capture clear images of events tens of thousands of light years away could be an even greater invention that superliminal travel.

 

[itchynackers]

Well tell it to Carl Sagan. If I remember correctly, it may have been Carl doing an episode of "NOVA". It specifically mentioned the alien riding a bike toward/away. And, it specifically mentioned our "now" and the alien's "now", and how he could see our future.

 

[Joseph C.]

Well tell it to Carl Sagan. If I remember correctly, it may have been Carl doing an episode of "NOVA". It specifically mentioned the alien riding a bike toward/away. And, it specifically mentioned our "now" and the alien's "now", and how he could see our future.

If that is the case I think he just made a mistake.

 

[itchynackers]

Ok, I found it. It was Brian Greene, not Carl Sagan. Whoops.
The whole program is good, but the nitty gritty begins at 21:30. The alien appears at 23:00. Watch through about 26:00.

http://video.pbs.org/video/2164065493