Could I be observing something travelling faster than light?

nope the craft going in the opposite direction its going to look like its going some fraction of the speed of light..

Now if I am understanding this correctly you are traveling at the speed of light in a craft that just launched a smaller craft with you in it. If you look at it in the means of waves, which is the way everything travels, the outside observer wouldn’t be able to see it immediately because as with sound, there would be a delay and what your seeing is the light still being reflected from where the craft once was. I believe that Einstein was a brilliant man but the only thing is that the only fuel available was chemical and they did not yet know of the things that could be achieved with quantum mechanics. Right now we have electrons can send faster than the speed of light so it is possible to go faster than the supposedly unsurpassable speed. As for the craft going in the opposite direction, you would see it but you would not be able to observe it if that makes sense to you.

No. You’d see it as traveling at the speed of light. If you think of C (the speed of light) as a ceiling, everything is just under that ceiling no matter what youre observing.

My understanding of the theory has it that you never perceive anything traveling faster than C (C is the handy symbol of the speed of light), but that every observer has a different perception of time from their own perspective, and that acceleration produces a shift in time, not just distance, especially as high relative speeds. From your own perspective, you can travel as fast as you like, but if you return to someplace you recognize, their clocks or calendars won’t match yours – you think you zoomed to Alpha Centauri and back in three months, but you get back to Houston and they tell you it’s been years.

It’s a redefinition of what velocity means. You’re right that within the bounds, two observers heading in opposite directions that tried to accelerate to 0.75 C would make something give. As I think I get it, the observed relative speed would be greater than 0.75 C but less than 1.0 C, but there would also be a relative time effect.

Part of the perception issue is that essentially ALL measurement and sensation we have is electromagnetic, and so propagates at C. In theory, if something were traveling faster than C, one might not be able to perceive it. The perception after all would tend to be a stream of reflected light traveling at 1.0 C…

So if I’m travelling @ .75C and the craft passes me going .75C, it would appear to me to be travelling around .999C?

Well greater than 0.75 but less than 1.0 – I’m not sure if 0.75 + 0.75 gives you greater than 0.9 or not. I don’t know either the formula for the function, or the exact terminology. I’ll see if I can find one.

Ok, so I’m trusting the calculator posted here: http://home.att.net/~srschmitt/script_starship.html

So if we enter 0.25 light years trip distance and 4 Earth-gravities of acceleration, we get numbers for a trip that would get up to 0.75 C maximum speed. So if we plan a ship coming the opposite direction at 4 Earth-gravities of acceleration, that would be like a 0.25 light year trip with 8 total G’s of acceleration. Plugging that in, the calculator gives 0.87 C maximum relative velocity.

I left out that the theory has it we will also experience an increase in mass and a contraction in distance… but since it’s all relative, that’d only apply to your perceptions of other things around you. Looking at the relativity calculator page at http://www.1728.com/reltivty.htm , I think your own ship would actually seem unchanged since it is not moving relative to you, but the passing ship would seem to be about twice as long and twice as massive as if it were stationary relative to you.

Zaku, I think you mean the ship going by his ship would get shorter (in the direction that its going, it will shrink) its called length contraction, which goes hand in hand with time dilation.
And theres an easy formula for figuring out what the observed speed of the second craft relative to you would be, but i cant remember what it is, sorry.

Oh, yes, you’re right. So, the passing ship would seem to be about half as long to you as it whished past. Since, like you and your ship, it wouldn’t seem that way to them (being nearly at rest compared to themselves and their own ship), I wonder what this particularly means unless you are trying to interact with them as they pass. The wiki page at http://en.wikipedia.org/wiki/Length_contraction has the formula and a cool-looking animated image.

You would see the passing ship until the exact moment the difference between the two ships became c (instantly when the observation device, your eye or a camera or telescope of whatever passes the observed object and it appears to decelerate, and then stop and vanish as the difference exceeds c) – then it would completely disappear from your view as any light used to observe it would be unable to reach it from your ship, and any light (or information) coming from the other ship wouldn’t be able to reach you until you or the other ship slowed to the point that the difference between you was less than c again – then you would see the other ship depending on how far apart you had traveled and how long the light from the other ship takes to make it back to you

I’m definitely a subscriber of the ‘variable speed of light’ theory, but even in this example the speed of light is not breached, so this shouldn’t offend anyone’s science

Take 2 cars that absolutely cannot accelerate to more than 75mph, they pass each other at their maximum speed of 75mph and once they pass each other, they appear to be going 150mph from each cars relative perspective, even though nothing really went faster than 75mph… same thing with your 0.75c ships passing each other, but the relative speed of the passing ship exceeds the speed at which physical observations can currently be made

Travelling and observing faster than light are two very different things, and I believe observing faster than light will be our first step towards actual time travel (of information anyways) – I can imagine faster than light observations being used to ‘see’ into the past under some circumstances