Is near-light-speed space travel possible? If not, what is the maximum speed of future spacecraft?

Question

I think it is possible, given the near-perfect vacuum of space. I think space engineers should start by trying to fire a golfball-sized probe towards Proxima Centauri, at about 99% of the speed of light. Maybe it'll take a century or two before engineers are able to achieve this sort of speed. Near-light-speed travel is very interesting and inviting because the crew wouldn't age (much) during the journey. Non-physicists sometimes make statements like, "even at the speed of light, it would take 4 years to reach Alpha Centauri," but, in fact, this is completely wrong. The journey time can be as short as you like, given a speed near enough to 299792.458 km per second. (Light takes about a twentieth of a second to cross the diameter of Earth. The Voyager 1 spacecraft would take 13 minutes. A craft ten times faster than Voyager would take about 1 minute. A craft ten times faster than this would take about 8 seconds. A craft ten times faster than this...)

Answer 1

> Non-physicists sometimes make statements like, "even at the speed of light,
> would take 4 years to reach Alpha Centauri," but, in fact, this is completely
> wrong.

Well, no... Actually, this is completely correct.
The distance between us, and Alpha Centauri (actually, Proxima Centauri would be more accurate) is about 4 light years.
A light year is a length unit, defined as the length that a photon (a particle that carries light) travels in one year.
Needless to say, light travels an a speed of light. So, if it takes 4 years for the light from Proxima Centauri to reach us, that is how lon git would take us to reach Proxima Centauri if we could move at the speed of light.

Perhaps, by " journey time can be as short as you like" you mean the relativistic effect when the time slows down for the moving object from the point of view of the observer at rest... That is true, that for the astranaut, moving close to the speed of light, the jorney could be quite short. It does not help us though, because for us, staying on Earth, it would still take at least 4 years for the spacecraft to reach the closest start, plus another 4 years, for the signal about it to come back to Earth - the total of 8 years before the earliest we can know the mission succeeded.

Answer 2

Put it this way -- travelling at the speed of light, it would take roughly four years to reach Alpha Centauri FROM THE PERSPECTIVE OF AN OBSERVER ON EARTH. If you were the one PILOTING the spacecraft, time outside the ship would appear to slow down relative to your personal time as you got closer to the speed of light -- so to you, it would seem like the trip only took a few minutes.

As far as how fast could a ship go....your main limits are going to be how much fuel you can carry, and how quickly you can accelerate using the fuel available. If you were able to construct a ship like the theoretical Bussard ramjet -- which would use an enormous magnetic field to "scoop" ambient hydrogen from the near-vacuum of space and use it for fuel -- your fuel supply would be effectively limitless, and top speed would eventually be determined by friction against that slight amount of hydrogen still in space. I read once that physicists have calculated that top speed to be about 60% lightspeed.

Answer 3

We can not go anywhere close to the speed of light. If we could get close the mass of the object would get greater and greater and would require more and more energy to accelerate. At you stated speed of 99% the speed of light it would require nearly infinite energy.
I don't understand your reasoning in saying it would not take long to reach Alpha centauri. If it takes 4 years (actually 6 years) for light to get there We could not get there in less time than light. It is not possible to go faster than the speed of light.

Answer 4

It will be possible but your statement is wrong that it wouldn't take4 light years but it would take 4.39 light years and you can,t say me Non-physicist as physics is my favourite subject, you wouldn't have said this if you knew distance of alpha centauri from earth. Teleportation would have been a better idea. You should refer to the site given below :-

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

Answer 5

We will never travel anywhere near the speed of light. But the only possibility is some thing totally different than our conventional travel like wormholes etc, will help travel intergalactic distances, not necessarily travelling at the speed of light.

Answer 6

err... I think you are wrong...If Proxima Centauri is 4 Light years away ...its light takes 4 years to reach us & therefore it would take 4 years to travel there @ the speed of light.

PS Actually what you need is a TARDIS....

Answer 7

If you were travelling faster then the speed of light and you turned on the spacecrafts headlights you would still bump into things - wouldn't you?

Answer 8

I agree with Daddy BD. You are not asking a question, you are looking for confirmation.

Let's just say, for confirmation purposes, your logic is flawed because you have overlooked several relativistic characteristics. Do a bit more research, especially on the Lorentz transform and how it affects mass and energy. Then ask your question again.

Answer 9

Seems like you got your mind made up. So are you looking for someone to prove you right or wrong? One thing, nobody can tell you what the future holds new discoveries are being made everyday.

Answer 10

Yes.