Special Relativity DP (1 Viewer)

[ND]

"Discuss the implications of mass increase, time dilation and length contraction for space travel".

Ok i assume they mean future space travel or something, cos at current speeds, these don't come into it at all. The only thing i can think of is that time dilation will mean that if you're travelling very fast for extended periods of time, when you get back to earth you'll be in the 'future'. Maybe mass dilation means that great accelerration is required because the greater teh velocity teh greater the mass. I really can't think of anything else.

Thanks for any help.

 

[...]

hmm...u got the time dilation going...
as for mass dilation...if u were to travel really really fast (ie close to speed of light), ur mass will increase(ie mass dilation) and hence, to require to have such high energy to move such big mass requires a lot of energy(E=mc^2)...from this, liquid fuel may not be powerful to do so...

 

[Ragerunner]

Is there really any implicaitons for length contraction? It's not like its a really bad thing.

Time Dilation and mass increase is important if new technology comes about. time dilation will essentially be a problem of time, in that when you complete your trip, all the people you know could already die of old age.

Mass increase also a problem as more fuel is required to propel the rocket as mass increase,

 

[Constip8edSkunk]

einsteins theory of relativity implies 1 cannot accelerate 2 the speed of light, so some method must b found 2 bypass this

time dilation while allowings occupants to travel far distances as time passes slower 4 occupants creates a problem where incoherence between occupants and outside world will b created... ie the ship will b effectively arriving from the past. future technology at the same time may have developed faster modes of travel.

length contraction is the other side of the coin of time dilation... appearance of shorter distances etc etc

mass dilations means it will b harder 2 accelerate as u draw near the speeds of light and the energy required vs velocity achieved will approach an asymptote... hence enormous amount of energy is required 2 approach c, and new forms of fuel/propulsion must be developed.

 

[+:: $i[Q]u3 ::+]

time dil - ppl can travel seemingly faster
length cont - distance to planet seems shorter
mass dil - spaceship gets too fat, too much energy required and the budget's blown.

 

[Rahul]

great answers

looked at the benefits of special reletivity and the problems with it...i would have jus stuck to the *benefits* [time dilation & length contraction], but this clears up some things defintely.

the mention of the fact that new means of fuel must be developed would be a certian mark.

 

[Fosweb]

Originally posted by +:: $i[Q]u3 ::+
length cont - distance to planet seems shorter

Remember that this is for the observer travelling at these great speeds, so whilst the astronaut will feel the journey to take less time, people working say, at NASA will still see the journey taking a long time.

The implications are: due to mass dilation and special relativity: we can never reach speeds great enough to make it to even the nearest galaxy within a lifetime of one astronaut.
even the nearest galaxy, which is greater than a MILLION light years away, would take a million years to reach at the speed of light.
we are unsure currently however, how the contraction of the universe works exactly with length contraction, and how much this journey would be shortened by when travelling at these high speeds.
plus - firstly - we have to find an efficient energy source that will allow us to get to speeds great enough to even see these effects.

 

[sunken eyes]

i didn't think that length actually contracted for the object, it only appears contracted to observer. ie; AT 3/4 C, IT IS GOING TO TAKE you 4/3 years to go a light year. it is only to observer that anything changes.
and the usual crap about nothin can reacj the speed of light because it will have infinite mass., and there fore cannot be accerlerated.

 

[ND]

Thanks for the replies everyone.

 

[stag_j]

i'm wondering.... ive heard people talk about how it's impossible to accelerate to the speed of light, and yet in theory if you could jump to a speed faster than that of light then that would be OK.
How would that work? Using the time/length dilation equations you end up with a negative square root...

 

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but "basic" stated that no object can travel up to or faster than speed of light except light itself...

 

[Ragerunner]

light can't travel faster than itself

 

[...]

i meant light travels at max 'c'...sorry for my poor language...

btw, i read it somewhere that this dude somehow did something to the spectral to the light where its blue or some shit and that afterwards the new "light" travels faster than 'c'...weird

 

[stag_j]

yeh i've read that thing about making some wavelengths of light travel faster than the rest, but i think thats just playing tricks... besides, its only light - so an actual object with mass wouldnt be able to do this.
but what i was talking about is things that i have heard where it is possible to somehow jump to a speed faster than that of light. kinda like light-speed is a barrier that can't be gone through but if you could somehow get over it then things would be possible.
i'll have a look round tomorrow and see if i can find something related to it

 

[Jumbo Cactuar]

WTF?!! Is everyone damned sure time dillation actually slows down/speeds up time....I didn't think it was a frickin' time machine. Wasn't it just relative because light has velocity? Not that time was actually running slower/faster, it is just observed to run slower/faster...damn this topic is confusing and my teacher really doesnt know how to explain stuff, but isn't it just relativety, simultaneity and frames of reference? Oh well maybe im wrong again

 

[Fosweb]

Time appears slower on a moving clock.

Time MUST change. If you take the equation, d/t = s:
Speed is always constant (c), so then distance and time are the two that variate in order to give a constant 'c'. This is different from the Newtonian way of thinking, where speed can change.
Remember we measure the metre now as the distance light travels in 1/300000000 of a second, so that distance will always be the same.

Time dilation slows down in the perspective of an external observer. So, if you were ON a spaceship, travelling at 0.9c, then YOUR journey's time, compared to time passing for someone NOT going that fast (such as someone on earth) would APPEAR shorter. It all depends on where you are. Not that its been proven, because we cant go fast enough yet, but I don't think that you feel time going faster on the spaceship, its just a comparison.
(This is the basis of the Twin Paradox also... Twin that returns from a space journey being younger than twin that stays on earth.)

 

[Constip8edSkunk]

put it this way, time isnt absolute, it is relative to different observers(eg, faster/slower)