Naked Science Forum

General Science => General Science => Topic started by: Seany on 13/04/2007 11:54:11

Title: What weird and cool effects occur when two gigantic mirrors face each other?
Post by: Seany on 13/04/2007 11:54:11

I was just thinking.. But wouldn't it look like a loooooong path down? Because it just keeps reflecting and reflecting and reflecting and again.. and again..

Title: What weird and cool effects occur when two gigantic mirrors face each other?
Post by: Seany on 13/04/2007 15:00:47

Anyone kno about this one?

Title: What weird and cool effects occur when two gigantic mirrors face each other?
Post by: another_someone on 13/04/2007 17:05:27

That is the way they do experiments to measure the speed of light, by creating a very long light path using parallel mirrors almost perpendicular to the light source.

The reason why they must be almost perpendicular to the light source, rather than truly perpendicular, is that you have to have a way of introducing the light to the mirrors (and you also want an end point where to measure the light), so the light path still requires an start point and an end point that is outside of the mirrors.  If the mirrors were perpendicular to the light, you could have neither a start point, nor and end point, for the light path.

Title: What weird and cool effects occur when two gigantic mirrors face each other?
Post by: Seany on 13/04/2007 17:06:52

Haha yeah. Thanks. So they make it a fraction fraction fraction fraction from parallel, so that they go miles before they reach the end point, right?

Title: What weird and cool effects occur when two gigantic mirrors face each other?
Post by: another_someone on 13/04/2007 17:11:54

Quote from: Seany on 13/04/2007 17:06:52

Haha yeah. Thanks. So they make it a fraction fraction fraction fraction from parallel, so that they go miles before they reach the end point, right?

Yes, except, I'm sorry, what I got wrong was that it is not that the mirrors are not parallel, but the the light path is not perpendicular to them - I have now corrected that.

Title: What weird and cool effects occur when two gigantic mirrors face each other?
Post by: Seany on 13/04/2007 17:13:19

Ohhhh.. Yep, that makes more sense. [:D] So the first light ray which they send is at like 89.9999 degrees from the mirror. Kk Thanks [:D]

So what cool experiences would you have? Just a loooooong tunnel?

Title: What weird and cool effects occur when two gigantic mirrors face each other?
Post by: neilep on 13/04/2007 17:14:56

George...this is very interesting....what measure of distance do they obtain measuring the speed of light like this ?

Title: What weird and cool effects occur when two gigantic mirrors face each other?
Post by: neilep on 13/04/2007 17:15:51

............and why do they need to check for the speed of light anyway.....it's 'C'  isn't it ?

Title: What weird and cool effects occur when two gigantic mirrors face each other?
Post by: Seany on 13/04/2007 17:18:45

Whats the 'C'?

Title: What weird and cool effects occur when two gigantic mirrors face each other?
Post by: Seany on 13/04/2007 17:19:21

Oh constant? Yes.. But maybe when they first found out about light.. They needed this to measure the speed of it.

Title: What weird and cool effects occur when two gigantic mirrors face each other?
Post by: Batroost on 13/04/2007 20:11:38

Just to make things a bit tricker...

The meter is defined in terms of the speed of light i.e. it was redefined in 1983 as the distance traveled by light in a vacuum in 1/299,792,458 of a second.

So when people make highly accrate measurements of the 'speed of light' they are really setting an accurate length scale...

Title: What weird and cool effects occur when two gigantic mirrors face each other?
Post by: neilep on 13/04/2007 20:32:06

Quote from: Batroost on 13/04/2007 20:11:38

Just to make things a bit tricker...

The meter is defined in terms of the speed of light i.e. it was redefined in 1983 as the distance traveled by light in a vacuum in 1/299,792,458 of a second.

So when people make highly accrate measurements of the 'speed of light' they are really setting an accurate length scale...

Ah !!..this is great..THANK YOU Batroost and welcome to the forum !

So, in this case the speed of light is used as a calibration tool...a measuring device !!..excellent !!

Thanks

Title: What weird and cool effects occur when two gigantic mirrors face each other?
Post by: Seany on 13/04/2007 21:49:22

Oh, so it's like a new measurement?