Does space travel work, like how it does in sci-fi movies?

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In sci-fi movies, space travel equats to time travel it seems like in movies like Interstellar, Aliens, and Planet of the Apes. But does it actually work like that, that the further you travel into space, the more you time travel?

Without getting too far into relativity, no, that's not how that works.

In Aliens, she was asleep for 54 years - it wasn't "time travel", so much as she was frozen and didn't age for that 54 years, while coincidentally floating in space. Ripley "traveled through time" in the same way as Phillip J Fry in Futurama. Frozen and not aging, is all.

In other movies, it has less to do with "traveling through space" having the effect of "time travel" and more to do with time dilation related to the the acceleration of the craft in relation to the observer or source from which they are traveling way from. It's not that you travel thru time as you go deeper in space as it is as you accelerate towards the velocity of the speed of light, time dilates relatively between the two locations - similar to the time dilation effect that occurs after passing the event horizon of a black hole.

Oh okay. Well this is not space related, but if that's the case, then why did Ripley choose to freeze herself or why did they chooes to freeze themselves in Planet of the Apes then, if it wasn't anything related to the space travel?

If we knew how to make it work, we'd be doing it.

Not only are the distances huge, but weightlessness has some serious consequences for the human body.

The Sci-Fi solution is to "freeze" people for the decades of travel that would be needed, otherwise they'd die before they arrived. And it would make for a very boring film.

Ironically perhaps, the comedy show Red Dwarf has been more accurate in exploring the isolation, tedium and feelings of crushing inconsequence of living in deep space than some serious sci-fi books and films.

Dude...it has to do with interstellar distances.

You have to grasp the concept of the size of distances in space.

Even the nearest stars, our next door neighbors, are unimaginably far away.

So if you we were to actually send astronauts to Alpha Centauri (our next door neighbor) it would take vast amounts of time for them to get there.

So when sci fi writers imagine future space travel it involves either (a) putting the astronauts into suspended animation in cryogenic pods, or (b) the space craft moving so fast that Einstein's relativity kicks in to slow down the passage of time itself for those astronauts relative to time for the back home folks, or (c) a combination of both.

Let me explain.

Whenever you look at the night sky you are, in effect, engaging in time travel. Thats because most of the brightest stars in the night sky are several dozen, or several hundred, light years away. That means it took the light from those stars dozens, or hundreds, of years to reach us. Which means when you look at a star in the Big Dipper thats thirty light years away you are seeing the star as it looked thirty years ago. Not how it looks now.

With binoculars you can see the Andromeda Galaxy, as a small fuzzy patch of light. A vast galaxy comparable to our own. And the Andromeda Galaxy is two MILLION light years away! The light that reaches your eye from Andromeda started its journey when humans had not even evolved yet.

So if you were to fly a space ship to a planet around a even a nearby star (that might even visible to the naked eye), and you were traveling at the speed that NASA is able to fly astronauts today it would take you thousands of years. Several human lighttimes. Ergo- you would have to either have multiple generations living on the space ship, or put yourself into temporary deepfreeze (and have a computer revive you on schedule when you arrive), or have a new form of propulsion that could power you a big fraction of light speed (in which case time itself would slow down for you- look up Einstien).

To reiterate -just to drive home the point.

Light travels at 300 thousand kilometers a SECOND. Or at 186 thousand miles a SECOND.

The Moon is less than one and half "light seconds" away. Light takes eight minutes to get to Earth from the Sun. Light takes about half of day to get past Pluto. But the nearest exo star system, Alpha Centuari, is more than four light years away (light takes four years plus to get there). It took decades for NASA probes to get to the orbit of Pluto. So ...do the math about how long it would take to get to Alpha Centauri with present day technology.

Last edited by naturalplastic on 14 Jan 2021, 2:29 am, edited 1 time in total.

Oh okay, makes sense. Thanks.

Ahh, smeg! (I have the first eight seasons on DVD.)

Faster-than-light travel does not work at all.  Movies that depict FTL travel do not depict reality.

Totally agree. If one could push an object with mass to near the speed of light, the internal forces would convert it back into the light energy that it was made from. About the only place where that could possibly happen is deep inside of a black hole. At that point, the measurement of time becomes irreverent.

What would happen if you drove your car at the speed of light, and then...turned on your headlights?

Would the light ...pool up inside your headlights because it couldnt get out?

Oh okay thanks. That makes sense. Thanks.

At the speed of light, you would travel an infinite distance in what for you would be an instant -- your subjective time inside the car would be zero, while objective universal time outside the car would be forever.  By the time you decelerated to a stop, there would be no more universe, as even the nucleons (neutrons, protons, et cetera) would have decayed and fragmented into a dim, radioactive haze.

While reading, I started thinking and not being sure what i remember of this but:

I'm not sure, but it seems you are mostly referring to states similar to inside a black hole? And I think at lightspeed mass is infinite, but the speed is lightspeed(its a constant). Maybe we dont have the same rest frame?

Since the car has mass, it cant reach light speed before its constituents are a haze of electromagnetic radiation etc ie photons (light), electrons, neutrinos(released from the proton) and possibly quarks!? I do not remember anything about neutrons traveling at lightspeed.

One funny thing about the car at light speed is that it will be pancake shaped and thinner than a proton core, even the nucleuses running inside the CERN ring, at more than 99 percent of lightspeed, are at their speed flattish. And the total energy of the car will create a black hole i think. Energy=mass*lightspeed*lightspeed

Cheers
Gragzy

Yes this is called the twin paradox: when you return to the start of the travel, your twin that stayed at the start will always be older according to your clock and the twins clock, the longer and faster you travel the shorter time you have lived compared to the twin. This actually governs how quickly the GPS clocks on earths surface and the cocks on the GPS satellites tick. If they tick at the same speed, the error in where your GPS unit will say you are will be off by hundreds of meters within a few days. So the tick rate on the surface of the earth and up at the satellites are different bc they travel approx 11000 m/s faster than you. At this level of accuracy even the difference in the gravity field at surface and satellite accounts for a difference. But for this effect to be visible you need to think the Sun and Mercury system where Sun gravity folds space to a much greater extent than between Earth and satellites. Mercury do not orbit the sun by Newtonian laws, you need the added stuff by Einstein

Cheers '')

Obviously; however, the question depended on a subjunctive clause that included the word "IF".  No one ever stated that the hypothetical car or its hypothetical occupant had to have mass.  Sometimes, you just have to play along to get the point across.

True as far as i know, but there is something called spacetime, and warping it to achieve nonlocally faster than lightspeed is possible if somewhat expensive on the energy front. As a mater of fact, far away in the universe whole galaxies are moving away from us faster than light. Bc spacetime is expanding. As long the spacetime locally is moving below lightspeed, that part of spacetime can move as fast it want relative to the rest of the universe, spacetime doesn't care, at this scale even conservation of energy fail.

This is hard to grasp i know, its a preposterous universe we exist in. And i cant claim i tell it correctly, so watch ustubbies from real Cosmologists.

Cheers
Gragzy