Travelling at the speed of light?[Question]

[Heat]

Simple question(Clearly hypothetically speaking by the way):

How long could you technically travel at the speed of light? [Side question: When people talk about travelling at the speed of light, why do they never mention the thousands of rocks you would hit every millisecond? Is it because of some law in physics or something that prevents that from occuring(dont know what to call it)? It would seem that you would never be able to travel that fast due to how many asteroids and objects in space you would hit, but I assume i'm wrong]


Assuming everything was in place accordingly, is there anything that would stop you? Would you face any physical problems from travelling that long at that speed?

[Aoi Magi]

There are far worse barriers than asteroids while traveling at lightspeed, the first being the energy requirements. The space is too vast and the asteroids are not as closely packed as hollywood would have us believe, so charting a path while avoiding them is not that hard at all.

However even if we can gain lightspeed travel, it would still take us a few thousand years to get to the nearest star systems, not too promising when you think about it. This is where traveling through wormholes seem like a more lucrative idea.

[Heat]

There are far worse barriers than asteroids while traveling at lightspeed, the first being the energy requirements. The space is too vast and the asteroids are not as closely packed as hollywood would have us believe, so charting a path while avoiding them is not that hard at all.

However even if we can gain lightspeed travel, it would still take us a few thousand years to get to the nearest star systems, not too promising when you think about it. This is where traveling through wormholes seem like a more lucrative idea.

No offense but you should read the question first, I said "clearly hypothetically speaking" as in "assuming we can travel at the speed of light", not concerned with the energy requirements. More as in if there is anything in space, or any limitation of physics that would render us unable to keep travelling.


Also I am asking(but this may have been more un clear) how long could we travel, meaning without a specific destination and assuming we could keep going forever in space. Is there anything (in space) preventing us from travelling endlessly, basically hypothetically assuming for the purpose of the question that we have advanced enough technology.

[Thumpalumpacus]

It's my admittedly simplistic understanding that the closer to light speed you go, the higher the energy requirements get until they are infinite. Additionally, time dilates the closer you get to c, and when traveling at that speed time essentially stops.

No doubt one of the several physwhizzes here will pull me up by the short hairs, but that's what I've gotten out of my layman's readings.

[Minimalist]

You mean this




ain't gonna happen?

[vorlon13]

There are many problems with travel at +99%C.

The background radiation of the universe ahead of you will be extremely blue shifted and extremely dangerous.

Rocks and asteroids are few and far between, the bigger and much more frequent issue would be microscopic grains of dust. They will smack with astonishing, vicious energy and will be extremely dangerous.

Accelerating to that speed is extremely difficult. Even harnessing large nuclear explosives to propel a craft might be good for less than 0.1C. Even antimatter, unless used extremely efficiently won't do it. There is a concept called a Bussard Interstellar ramjet, and it actually gets more efficient the faster it goes, but it is extremely difficult imagining how to build one, let alone piloting it around the galaxy.

The Space Shuttle accelerated for 2-3 Gs for ~8 minutes just to reach 17000 MPH, to reach a high percent of C requires acceleration of 1 G for a year, or 2 Gs for 6 months, or 3 Gs for 4 months, it is difficult to even imagine getting up to those speeds, and then recall you also have to take fuel to decelerate at your craft at the destination.

You're better contemplating large multi-generational ships in the 0.05C range. Then large nukes can work, and actually work well. Preliminary designs and concepts were worked out in the 60's. If you're willing to spend ~400 years building it, a multi-generational craft capable of taking 50,000 people and the materials to provision a viable colony is possible. Refueling and refurbishing (or duplicating) the craft at the destination would take some centuries, and then one or more colonizing attempts could be made, assuming the first destination was well chosen.

That technology could be used to explore and colonize our galaxy in a couple or few million years.

[Aoi Magi]

There are far worse barriers than asteroids while traveling at lightspeed, the first being the energy requirements. The space is too vast and the asteroids are not as closely packed as hollywood would have us believe, so charting a path while avoiding them is not that hard at all.

However even if we can gain lightspeed travel, it would still take us a few thousand years to get to the nearest star systems, not too promising when you think about it. This is where traveling through wormholes seem like a more lucrative idea.

No offense but you should read the question first, I said "clearly hypothetically speaking" as in "assuming we can travel at the speed of light", not concerned with the energy requirements. More as in if there is anything in space, or any limitation of physics that would render us unable to keep travelling.


Also I am asking(but this may have been more un clear) how long could we travel, meaning without a specific destination and assuming we could keep going forever in space. Is there anything (in space) preventing us from travelling endlessly, basically hypothetically assuming for the purpose of the question that we have advanced enough technology.

No offense, but you should try to understand the response first.

Simply stating a scenario is hypothetical, doesn't magically change all the associated rules. Without predefined rules, anything is possible in a hypothetical scenario. If Flash can speed his way through solid walls, hypothetically spaceships can pass through solid asteroids.

[Alex K]

Exactly what Parkers Tan and Vorlon said

Though the time dilation can work in the travellers' favour in a sense, because by accelerating you can arbitrarily shorten the time that passes in the spaceship. But as seen from the outside, a lightyear will always take more than a year to traverse unless there are serious flaws in relativity theory.

We're talking about ordinary movement through space, no wormholes or exotic warp drives as poroposed by Alcubierre.

[houseofcantor]

Foreverz! (like me and my Gwynnies!   )

Things go at the speed of light because they have no mass. Massless particles have one speed - c - that's all they get. They also have no time. So, foreverz. As has been mentioned, these limitations indicate that to accelerate to c takes essentially infinite energy, which builds up to infinite mass, and then you have no time. So "accelerating to c" directly is likely to remain on the fiction side of science fiction.

And yes, if you were to somehow directly able to accelerate to near c, if you hit something, you'd vaporize your cruiser. Some fictional scenarios have ships that project a forward force field to push these pesky particles out of the way; I know Reynolds likes to coat his cruisers in a thick plating of ice. Where there's imagination the possible solutions are endless.

But, never do nothing direct when there are indirect means of achieving the same result. Things like the Alcubierre drive posit warping space into essentially a gradient that is higher behind your cruiser and lower in front so that it is theoretically possible to skirt relativistic limitations. Unfortunately this requires negative energy (and likely exotic matter) things theorized but never actually observed. Another potential benefit of this hypothetical negative energy may be to reduce the effective mass of the craft. In some warp-drive scenarios, the amount of warp available varies directly with the amount of mass reduction.

Another indirect potential methodology is nanoscale automation, the sending out of Von Neumann machines to build the ring structures necessary for the construction of wormholes. This potential eliminates relativistic constraint by ignoring the space between objects.

But yeah, foreverz, like me and my Gwynnies! 

[robvalue]

Ive always been confused by the idea that the relative speed of a collision gets capped at c. Assuming I got that correct, is that something I could understand by reading an article (if so do you know a good one) or is it going to be harder to understand?