- 05 Apr '07 00:44If you are traveling at the speed of light would you be invisble? because the light could not catch up to you casue you would be going faster. but then would you be visible from the direction that you are moving becasue you would run into the light rays which would then reflect off of you.???
- 05 Apr '07 02:09

It's impossible because as you get closer to the speed of light, your mass increases to greater and greater proportions of what it is, so more and more energy is required to accelerate and eventually you will have an infinite mass therefore an infinite amount of energy would be needed to accelerate faster.*Originally posted by bloodyboy***why is it impossible?** - 05 Apr '07 04:59

You would also become a very very thin pancake shaped object that would expand laterally to the edge of the known universe so you would be like a moving pancake of infinite mass. You would become two dimensional.*Originally posted by prosoccer***It's impossible because as you get closer to the speed of light, your mass increases to greater and greater proportions of what it is, so more and more energy is required to accelerate and eventually you will have an infinite mass therefore an infinite amount of energy would be needed to accelerate faster.** - 05 Apr '07 07:23Many questions begins with "If I go in the speed of light..." then the rest of the question irrelevant.

If you expand the E=MC2 equation you'll end up with a division by zero when you have the speed of light. So the question could equally be written: "If I divide by zero..."

The conclusions of the phenomenons when you enter the speed of light could be anything. Like the moon turn into cheese, the universe would explode, I get a raise from my boss and anything impossible.

But we don't have to deal with this kind of questions because the speed of light is unreachable if you have the slightest of mass in you. - 05 Apr '07 11:42

The moon could turn into cheese!*Originally posted by FabianFnas***Many questions begins with "If I go in the speed of light..." then the rest of the question irrelevant.**

If you expand the E=MC2 equation you'll end up with a division by zero when you have the speed of light. So the question could equally be written: "If I divide by zero..."

The conclusions of the phenomenons when you enter the speed of light could ...[text shortened]... stions because the speed of light is unreachable if you have the slightest of mass in you. - 05 Apr '07 13:29

And why doesn't PI just equal 4 for krists sake?*Originally posted by FabianFnas***Many questions begins with "If I go in the speed of light..." then the rest of the question irrelevant.**

If you expand the E=MC2 equation you'll end up with a division by zero when you have the speed of light. So the question could equally be written: "If I divide by zero..."

The conclusions of the phenomenons when you enter the speed of light could ...[text shortened]... stions because the speed of light is unreachable if you have the slightest of mass in you. - 05 Apr '07 19:05Pi does not equal 4, even in certain topologies. Pi=3.14159... in any topology. It may be that the ratio of the circumference of a circle to its diameter is 4 under a particular metric (and using some obvious definition of circle), but in that case it is not pi!

Furthermore, some of the above suggested violations of possibility seem more grave than others because presumably they involve different sorts of possibility. It's not possible for me to fly to Pluto in a week, but this is a practical impossibility, rather than a physical or logical impossibility. Similarly, it's a physical rather than logical impossibility that precludes any massed object travelling at light speed and so it seems odd to invoke ex falso quodlibet, a principle of logic, for a question framed in the form of a counterfactual about physical laws. I think it is comparably odd to a claim of the form 'if it were the case that I could fly to Pluto in a week, one would equal zero'. I'm confident that the question-setter here doesn't intend any logical inconsistency in his/her question and would gladly concede that if it were the case that an object (with mass) could travel at light speed, it would not be the case that nothing (with mass) could travel at light speed.

Perhaps the question would be better phrased 'If an object with no mass travelled at the speed of light, would it be invisible?' Indeed some particles are massless and do travel at the speed of light - in particular the photon! And photons certainly aren't invisible (at least at some level of detection).

Now suppose some massless object A is travelling at velocity c relative to some observer O and it emits a photon along a geodesic in the direction AO it would velocity c relative to A and to O! Similarly if O emits a photon along a geodesic in the direction OA, the photon would have velocity c relative to both A and O. Hence, with appropriate light sources, A need not be invisible to O! - 05 Apr '07 19:18It all depends on how the light strikes the object, no matter the speed or impossibility. If you hit the light head on, you'd basically absorb the light. Light would never reach you from behind, but from any random angle, you'd be visible. At least where you were would be visible to something sensitive enough to see it.

And light speed is not impossible. Photons do it all the time. - 05 Apr '07 19:30

On a flat surface pi is certainly 3.14159... But if you define pi as the circumference of a circle divided by its diameter on a surface then, if the surface is spherical pi is less thatn 3.14..., if the surface is hyperbolic pi is greater than 3.14..., perhaps even 4.000...*Originally posted by treborbassett***Pi does not equal 4, even in certain topologies. Pi=3.14159... in any topology. It may be that the ratio of the circumference of a circle to its diameter is 4 under a particular metric (and using some obvious definition of circle), but in that case it is not pi!**

Now, this is of course if you want to fiddle with the reasoning. In ordinary, flat, circumstance, pi is ofcourse as it use to be, namely 3.14159... - 05 Apr '07 19:40 / 1 editTrue....however:

E = (mc^2) / sqrt (c^2 - v^2)

Even if m = 0, c^2 - c^2 = 0, and you can't divide by zero...ever. So shouldn't photons be limited by the speed of light as well?

Edit: Or maybe E = (mc^3) / sqrt (c^2 - v^2), cuz the Lorrentz Equation is sqrt(1 - v^2/c^2)... Bah, it's something like that.