So, you're travelling at the speed of light.....

[LHRFlightman]

And you hold out a mirror in front of you.

Do you see;

A. Nothing but he dark void of emptiness.
B. Your arm, hand and a mirror but no reflection.
C. Your arm, hand and a mirror, and a reflection.
D. Something else my work colleague and I haven't thought of.

PH, discuss.

[Lynchie999]

depends where the light source is coming from ?? in front or behind you ?

[balls-out]

LHRFlightman said:

And you hold out a mirror in front of you.

Do you see;

A. Nothing but he dark void of emptiness.
B. Your arm, hand and a mirror but no reflection.
C. Your arm, hand and a mirror, and a reflection.
D. Something else my work colleague and I haven't thought of.

PH, discuss.

Assuming you mean 99.999% of speed of light, then everything would be completely normal.

There is no such thing as absolute speed, only when measured against another reference point. I guess in this example it'll depend on your relative speed to your light source, given that you, hand and mirror are travelling at the same speed.

[LHRFlightman]

Lynchie999 said:

depends where the light source is coming from ?? in front or behind you ?

Directly overhead.

[HoHoHo]

I would suggest that on the assumption you are travelling on a plane at 600mph and hold a mirror out in front of you (you can't because of the wind but ignore that), you see what is there because it's all travelling at the same speed then the speed of light would be no different?

However, what if you hold a microphone in front of you whilst travelling at mach 4 and fart

[MrCarPark]

If you were travelling at the speed of light could you extend your arm at all?

[Einion Yrth]

1) You have rest mass, you cannot travel at the speed of light.
However assuming asymptotic approach to C...
2) The speed of light is frame invariant, within your frame of reference everything appears completely normal.
3) Things you see looking out of the window are interestingly different.

[LHRFlightman]

Einion Yrth said:

1) You have rest mass, you cannot travel at the speed of light.
However assuming asymptotic approach to C...
2) The speed of light is frame invariant, within your frame of reference everything appears completely normal.
3) Things you see looking out of the window are interestingly different.

You say in my frame of reference everything seems completely normal? But is that really correct? I've seen Star Trek and when the Enterprise warps, it's anything but normal.

[HoHoHo]

LHRFlightman said:

Einion Yrth said:

1) You have rest mass, you cannot travel at the speed of light.
However assuming asymptotic approach to C...
2) The speed of light is frame invariant, within your frame of reference everything appears completely normal.
3) Things you see looking out of the window are interestingly different.

You say in my frame of reference everything seems completely normal? But is that really correct? I've seen Star Trek and when the Enterprise warps, it's anything but normal.

Ah, but warp drive is in theory faster than light so there may be a difference?

[Simpo Two]

HoHoHo said:

Ah, but warp drive is in theory faster than light so there may be a difference?

As I understand it it warps space; ie brings where you want to be closer to where you are. So you get there faster, stepping through the ruckley bits, as it were. It's a bit like syaing 'this river is too wide' so you make it narrower.

[Flying Madman]

Einion Yrth said:

1) You have rest mass, you cannot travel at the speed of light.
However assuming asymptotic approach to C...
2) The speed of light is frame invariant, within your frame of reference everything appears completely normal.
3) Things you see looking out of the window are interestingly different.

Asymptotic convergence and frame invariance is a good start - but does the traveller/mirror frame at near-C velocity mean the beam of light is never going to reach the eye of the traveller = they won't be able to see the image in the mirror?

[evenflow]

If c is nature's speed limit, but c stays the same to any observer... I am travel at 99.9999% of c and hold the mirror in front of me, isn't the light coming off me and hitting the mirror travelling at 1.99999 x c?

:brain explodes:

[davepoth]

At the speed of light there is no "in front"; as objects near the speed of light they get shorter, so an object at the speed of light has no length at all - your eyes would occupy the same space as your mirror. The answer is white, anyway.

http://www.metacafe.com/watch/5733303/traveling_at...

[Ilovejapcrap]

LHRFlightman said:

And you hold out a mirror in front of you.

Do you see;

A. Nothing but he dark void of emptiness.
B. Your arm, hand and a mirror but no reflection.
C. Your arm, hand and a mirror, and a reflection.
D. Something else my work colleague and I haven't thought of.

PH, discuss.

The back to the future car

[Flying Madman]

davepoth said:

At the speed of light there is no "in front"; as objects near the speed of light they get shorter, so an object at the speed of light has no length at all - your eyes would occupy the same space as your mirror. The answer is white, anyway.

http://www.metacafe.com/watch/5733303/traveling_at...

I would say with approaching the speed of light objects get extended - ultimately reaching infinite length at c - so mirror relative to the traveller, both in the same frame and both extended almost to infinity, is still the same old mirror in the traveller's perception. The question remains about the image in the mirror.

[Morningside]

I would say "C" as its relative (is that how it works?)

When they say speed of light, what light are we talking about? Red, green, blue? All the spectrum? Is there a cut off point of frequency? If so, why?

[Flying Madman]

Colour in the visible part of the spectrum is determined by wavelength/frequency, velocity is the same across the whole spectrum.

[Martin4x4]

LHRFlightman said:

And you hold out a mirror in front of you.

Do you see;

A. Nothing but he dark void of emptiness.
B. Your arm, hand and a mirror but no reflection.
C. Your arm, hand and a mirror, and a reflection.
D. Something else my work colleague and I haven't thought of.

PH, discuss.

C.

[Dr Jekyll]

balls-out said:

Assuming you mean 99.999% of speed of light, then everything would be completely normal.

There is no such thing as absolute speed, only when measured against another reference point. I guess in this example it'll depend on your relative speed to your light source, given that you, hand and mirror are travelling at the same speed.

But if I'm driving at 99.999% of the speed of light, how fast are the tops of the wheels going?

[LHRFlightman]

Dr Jekyll said:

But if I'm driving at 99.999% of the speed of light, how fast are the tops of the wheels going?

Depends on whether you're running 16" or 22" surely?