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Questions tagged [speed-of-light]

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During interstellar travel, does time dilation make the trip shorter?

If it is 4.2 light years to the Alpha Centauri system, does the trip there take less time the closer you get to the speed of light? When considering time dilation, if we traveled at the speed of ...
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1answer
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Looking out the window of a subluminal spaceship, what would be the sight?

How would a star sky look for the observer flying on a subluminal spaceship (i.e., with the velocity close to the velocity of light)?
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Could Breakthrough Starshot proposed propulsion system be used in a regular size probe to accelerate it faster than any probe has been before?

Supposedly Breakthrough Starshot project wants to accelerate a capsule of the size of a mobile phone - according to one source - and of the size of the chip of a mobile phone - according to another ...
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323 views

Overcoming the speed of light thanks to ion thrusters

I am wondering if I could build an ion thruster, that is capable of exit velocity bigger that the speed of light. If I start with the equation for calculating exit velocity $v_e$ of a particle of ...
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Is the universe already colonized or are the Drake equation coefficients a much stronger filter: what are the cosmology issues with this paper?

http://www.fhi.ox.ac.uk/wp-content/uploads/intergalactic-spreading.pdf This paper posits a path to colonizing/probing the universe with lightweight (30g) or heavyweight (500t) probes based on 3 ...
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What percentage of the universe's galaxies are within our reply-lightcone before they're Hubble-flow expanded away too far to reply? [duplicate]

Because of the Hubble constant, how far can we now send a signal and still be in range to hear an immediately-issued (the moment they receive a signal) reply? And what percentage of today's visible ...
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94 views

Time when traveling around the speed of light [closed]

I heard that if you travel at the speed of light or faster (say, to the Kelper systems ) and come back, thousands of years may have passed but you haven't experienced more than a few. How is this ...
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737 views

Have we done any research trying to reach the speed of light? [closed]

Have we tried in the past to run tests or do research to reach the speed of light ?