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Old 15-05-2007, 03:34 PM
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ving (David)
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what would i see?

... what would i see if a placed a giant mirror in space 1 ly away and looked at myself in its reflection with a telescope?

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Old 15-05-2007, 03:49 PM
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erick (Eric)
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Nothing of yourself, unless you stay at your eyepiece for 2 years?

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Originally Posted by ving View Post
... what would i see if a placed a giant mirror in space 1 ly away and looked at myself in its reflection with a telescope?

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Old 15-05-2007, 07:01 PM
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You must be bored and me likewise, but I'm waiting for me 'egg to boil' so here goes.....

You would see nothing of yourself or possibly even the Earth.

Let's say for arguments sake the 'giant mirror' is the size of Earth or even Jupiter !

As the mirror relies on reflected light you would need a light source to generate the reflection. The Earth doesn't generate any light (part from artificial light we produce) the be reflected in the mirror the daylight side of the earth would need to be facing the mirror, in which case you wouldn't be able to use your scope to see yourself looking back as you would be on the dark side of the earth facing away from the mirror. Lets say for argument your looking at the mirror from the dark side, you wouldn't be able to see the earth at your location as it would be in the dark, unless you light yourself up to be seen on the dark side and the earth is a crescent shape (half light half dark). This is assuming that you could see this level of minute detail from that distance. The daylight side of the Earth maybe just a spec of off white, possibly grey ??

Apart from those practicalities, the light reflected back would have taken two years to get back to the Earth as pointed out by Erick, so you would be viewing the Earth as it was two years ago, not live. The light reflected from the mirror would reflect at the same scale ... at one lightyear distance we are a very small spec.

But since we are playing at a thought experiment and suspending reality to have a mirror the size of Jupiter, I guess you could suspend reality even more and see what you like in the mirror at any distance ... oh time's up my egg has boiled .....
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Old 15-05-2007, 08:01 PM
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I think, if an Alien built the mirror, which knows its purpose:

ving wants to see himself in the mirror

that can adjust the mirror in such a way that despite proper motion of the Sun and the earth revolution around the Sun

a mirror image of ving is always to see.

and: it must be a parabolic mirror with the Earth in the focus, otherwise the light diverges too much…
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Old 16-05-2007, 10:53 AM
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ving (David)
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silly me. i didnt consider the fact that we'd be looking t the dark side of the planet for starter and therefore no light being projected.... hmm.

lets change things just a bit then and put the mirror in orbit with the moon, this should make things easier and by rights you should see the near past?

how would this effect the outcome?
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Old 16-05-2007, 10:59 AM
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Knowing our luck it will be placed so the raflection of the sun hits the earth as a focused point of light and either 1. blow up earth 2. burn another hole into the ozone layer, 3. Stuff all night time viewing from earth or until the mirro has been destroyed.
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Old 16-05-2007, 11:05 AM
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Kal (Andrew)
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You would see yourself from two years ago causing a time paradox that will destroy the universe!!!!
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Old 16-05-2007, 11:47 AM
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You would see yourself as you were less than 2seconds ago as it only takes light approx 1 sec to reach the moon from Earth. Think about it though, you could get up to all sorts of mischief and then come back in 2 years time and watch a replay of it all.LOL
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Old 16-05-2007, 01:58 PM
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If there is a big mirror 16-17 ly out there, I might see myself in check flares and 2 inch platform shoes!
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Old 16-05-2007, 04:29 PM
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csb (Craig)
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Also, it depends on what position you are in when looking.

I can think of some very funny positions

And I won't even mention another one I just thought of

Sorry, I'll get off the Net now.

Bye
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