# Magnifying light speed Questions

Mike Hewson
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Joined: 1 Dec 05
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### RE: Hi Mike, Curious, what

Message 41315 in response to message 41314

Quote:
Hi Mike,
Curious, what do you think we would see (through the glass) at 99.9% the speed
of light?

I'll just re-state to make sure I have the scenario right: someone ( Bert ) travelling at 99.9% of c towards a mirror, observing his own reflection with a magnifying glass?
A couple of points, then:
- the magnifying glass collects light from the mirror to an image plane - which is stationary in Bert's rest frame. This will distort/enlarge etc what Bert sees according to the optical set up. Light travels at c with respect to this frame and light paths etc can be analysed in the usual way ( ray tracing, waves, even quantum electrodynamics if you like.... ).
- Bert's image of himself is generated from photon's emitted by him which travel ahead, 'hit' the mirror and return. Without loss of generality you can analyse this as a virtual Bert ( VeeBert ), heading toward the mirror plane ( from the other side as Bert ) at speed 99.9% c with respect to that plane. Admittedly there might be a phase issue with reflection, but let's ignore that.
- So take, now, Bert and VeeBert heading toward each other at a speed of 99.9% c with respect to said mirror plane. Convert VeeBert's motion in this frame ( rest frame of mirror ), to Bert's rest frame using Lorentz formulae.
- as pointed out this involves a time correction ( dilation or slowing down of VeeBert's behaviour with respect to Bert ) and the velocity of VeeBert with respect to Bert will be greater than 99.9% of c, but still less than c.
- So Bert looks through his looking glass, sees a delayed and slower version of himself looking back at him through a looking glass!
Phew!
Any holes in that anybody?
Cheers, Mike.

I have made this letter longer than usual because I lack the time to make it shorter ...

... and my other CPU is a Ryzen 5950X :-) Blaise Pascal

Ernesto Solis
Joined: 11 Jun 05
Posts: 57
Credit: 49,513
RAC: 0

### RE: RE: Hi Mike, Curious,

Message 41316 in response to message 41315

Quote:
Quote:
Hi Mike,
Curious, what do you think we would see (through the glass) at 99.9% the speed
of light?

I'll just re-state to make sure I have the scenario right: someone ( Bert ) travelling at 99.9% of c towards a mirror, observing his own reflection with a magnifying glass?
A couple of points, then:
- the magnifying glass collects light from the mirror to an image plane - which is stationary in Bert's rest frame. This will distort/enlarge etc what Bert sees according to the optical set up. Light travels at c with respect to this frame and light paths etc can be analysed in the usual way ( ray tracing, waves, even quantum electrodynamics if you like.... ).
- Bert's image of himself is generated from photon's emitted by him which travel ahead, 'hit' the mirror and return. Without loss of generality you can analyse this as a virtual Bert ( VeeBert ), heading toward the mirror plane ( from the other side as Bert ) at speed 99.9% c with respect to that plane. Admittedly there might be a phase issue with reflection, but let's ignore that.
- So take, now, Bert and VeeBert heading toward each other at a speed of 99.9% c with respect to said mirror plane. Convert VeeBert's motion in this frame ( rest frame of mirror ), to Bert's rest frame using Lorentz formulae.
- as pointed out this involves a time correction ( dilation or slowing down of VeeBert's behaviour with respect to Bert ) and the velocity of VeeBert with respect to Bert will be greater than 99.9% of c, but still less than c.
- So Bert looks through his looking glass, sees a delayed and slower version of himself looking back at him through a looking glass!
Phew!
Any holes in that anybody?
Cheers, Mike.

(you guys are so much fun)

Ok Mike, What will you see if you have only a magnifying glass in
front of you? What will I see through the glass?(No Mirror!)

Remember, I'm a rookie!
Thanks
Ernie S
Team Art Bell
God Bless

Ernesto Solis
Joined: 11 Jun 05
Posts: 57
Credit: 49,513
RAC: 0

### RE: RE: RE: Hi

Message 41317 in response to message 41316

Quote:
Quote:
Quote:
Hi Mike,
Curious, what do you think we would see (through the glass) at 99.9% the speed
of light?

I'll just re-state to make sure I have the scenario right: someone ( Bert ) travelling at 99.9% of c towards a mirror, observing his own reflection with a magnifying glass?
A couple of points, then:
- the magnifying glass collects light from the mirror to an image plane - which is stationary in Bert's rest frame. This will distort/enlarge etc what Bert sees according to the optical set up. Light travels at c with respect to this frame and light paths etc can be analysed in the usual way ( ray tracing, waves, even quantum electrodynamics if you like.... ).
- Bert's image of himself is generated from photon's emitted by him which travel ahead, 'hit' the mirror and return. Without loss of generality you can analyse this as a virtual Bert ( VeeBert ), heading toward the mirror plane ( from the other side as Bert ) at speed 99.9% c with respect to that plane. Admittedly there might be a phase issue with reflection, but let's ignore that.
- So take, now, Bert and VeeBert heading toward each other at a speed of 99.9% c with respect to said mirror plane. Convert VeeBert's motion in this frame ( rest frame of mirror ), to Bert's rest frame using Lorentz formulae.
- as pointed out this involves a time correction ( dilation or slowing down of VeeBert's behaviour with respect to Bert ) and the velocity of VeeBert with respect to Bert will be greater than 99.9% of c, but still less than c.
- So Bert looks through his looking glass, sees a delayed and slower version of himself looking back at him through a looking glass!
Phew!
Any holes in that anybody?
Cheers, Mike.

(you guys are so much fun)

Mike, What will you see if you have only a magnifying glass in
front of you?
What will I see through the glass?(No Mirror!)

The further you hold it away, what changes might
occur? (traveling at 99.9% the speed of light)

Remember, I'm a rookie!
Thanks
Ernie S
Team Art Bell
God Bless

Mike Hewson
Moderator
Joined: 1 Dec 05
Posts: 6,400
Credit: 206,667,044
RAC: 76,509

### RE: (you guys are so much

Message 41318 in response to message 41317

Quote:
(you guys are so much fun)

Quote:
Mike, What will you see if you have only a magnifying glass in
front of you?
What will I see through the glass?(No Mirror!)

The speed of his motion is not really a big issue with respect to the formation of any image within his rest frame. The beauty ( indeed the foundation ) of Relativity is that the speed of light ( in vacuo ) is constant regardless of choice of frame. Bert's motion will of course affect the pattern of arrival of light to his frame. The Lorentz contraction refers only to lengths along the line/vector of relative velocity between source and observer ( be careful how you read that ). Let's not forget good old Doppler shifting which will cause a blueing of light coming from in front of Bert, and a redden-ing from behind, compared to the stationary case. There is also an effect where you need to adjust the aim of an optical device due to relative motion. This was first found a few centuries ago with regard to telescopes - I can't remember who named it - analogous to leaning forwards when running in the rain to catch the drops in the bottom of a long bucket.

Quote:
The further you hold it away, what changes might
occur? (traveling at 99.9% the speed of light)

You'd see a different view of whatever tableau was apparent according to the various effects already mentioned. Do you have a special thought, prediction or worry here? Don't be shy .... :-)
Cheers, Mike.

NB. Einstein originally wanted to call his 1906 theory 'Invariant', referring to the constancy of light speed, but settled on 'Relativity' concerning how to relate measurements in different frames. Alas because of other semantic uses of the word 'relative', the effect has been a blossoming of mis-understandings of his ideas.

I have made this letter longer than usual because I lack the time to make it shorter ...

... and my other CPU is a Ryzen 5950X :-) Blaise Pascal

Ernesto Solis
Joined: 11 Jun 05
Posts: 57
Credit: 49,513
RAC: 0

### RE: RE: (you guys are so

Message 41319 in response to message 41318

Quote:
Quote:
(you guys are so much fun)

Quote:
Mike, What will you see if you have only a magnifying glass in
front of you?
What will I see through the glass?(No Mirror!)

The speed of his motion is not really a big issue with respect to the formation of any image within his rest frame. The beauty ( indeed the foundation ) of Relativity is that the speed of light ( in vacuo ) is constant regardless of choice of frame. Bert's motion will of course affect the pattern of arrival of light to his frame. The Lorentz contraction refers only to lengths along the line/vector of relative velocity between source and observer ( be careful how you read that ). Let's not forget good old Doppler shifting which will cause a blueing of light coming from in front of Bert, and a redden-ing from behind, compared to the stationary case. There is also an effect where you need to adjust the aim of an optical device due to relative motion. This was first found a few centuries ago with regard to telescopes - I can't remember who named it - analogous to leaning forwards when running in the rain to catch the drops in the bottom of a long bucket.
Quote:
The further you hold it away, what changes might
occur? (traveling at 99.9% the speed of light)

You'd see a different view of whatever tableau was apparent according to the various effects already mentioned. Do you have a special thought, prediction or worry here? Don't be shy .... :-)
Cheers, Mike.

NB. Einstein originally wanted to call his 1906 theory 'Invariant', referring to the constancy of light speed, but settled on 'Relativity' concerning how to relate measurements in different frames. Alas because of other semantic uses of the word 'relative', the effect has been a blossoming of mis-understandings of his ideas.

Just piercing into the unknown through eyes from around the world.
And so honored sir!
Ernie S
Team Art Bell
God Bless
P.S. Just Dreaming...

Misfit
Joined: 11 Feb 05
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### Carl Sagan on Albert

Carl Sagan on Albert Einstein, Special Relativity and the speed of light.

me-[at]-rescam.org

debugas
Joined: 11 Nov 04
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### RE: Carl Sagan on Albert

Message 41321 in response to message 41320

Quote:
Carl Sagan on Albert Einstein, Special Relativity and the speed of light.

I watched the film and have one comment about what high speed traveller would see. In the film when riding the bike the assertion of everything shrinking is wrong though it was right about everything ahead turning blue. At the end of the film ("10 years later" part )they gave the right demonstration of how high speed traveller would see things, namely that the objects ahead get stretched from the center