Amazing mirror designs and their uses

[robphy]

http://www.newscientist.com/gallery/dn16585-amazing-mirrors/1 (links to this and more)
http://www.math.drexel.edu/~ahicks/

 

[z0rn dawg]

At first I thought it was a lot cooler...I though it object's image was rotated. That would be nuts.

 

[Redbelly98]

Nice. Took me a few minutes to figure it out.

Spoiler

It's a cylindrical mirror.

 

[redargon]

It's a concave mirror, I'm not sure I understand the fascination? :shy:

 

[signerror]

Oh, the phone book. One day, I too will understand the geometry of spacetime. But not today. Too busy.

 

[Redbelly98]

It's a concave mirror, I'm not sure I understand the fascination? :shy:

The fascination: why are the letters in the mirror not reversed or upside-down?

Hint: a spherically concave mirror would flip the letters upside-down.

 

[redargon]

because it's cylindrically concave, not spherically concave, but you can see that by looking at the top cross section. It is pretty cool though. I used to love messing around with mirrors and trying to make things like periscopes with compact mirrors and toilet roll cardboard tubes. My mo used to get a little pissed that I was dismantling her compacts though

It's a little bit like those corner mirrors you get in bathrooms some times (a mirror on each wall in a corner). They used to freak me out, because your reflection isn't reversed. so if you raise your right hand, your reflection raises "his" right hand too. After years of learning how to comb your hair "in reverse" in a normal mirror and then stepping into a bathroom with one of these and your brain has to have a double take

 

[Redbelly98]

And, robphy was careful to find the spot where horizontal and vertical magnifications were equal in magnitude, but opposite in sign, to get a non-distorted image of the book.

Note also the stuff going on with the hole images, that are either behind or in front of the "focal point". The mirror's shadow has an interesting image as well.

 

[mgb_phys]

Unfortunately they choose a poor image to show this effect - New Scientist is a British publication, British books have the spine printed the other way around (title reads top-down) It confused us for a while!

 

[Redbelly98]

Sheesh, I completely missed the links in robphy's OP, and assumed robphy took the photo!

 

[robphy]

Sheesh, I completely missed the links in robphy's OP, and assumed robphy took the photo!

I was about to say
it wasn't me who took the photo... but you already discovered that.

 

[Redbelly98]

I also thought it was a simple cylindrical mirror, but this suggests otherwise:

(Andrew) Hicks, a mathematician at Drexel University, Philadelphia, used computer algorithms to generate the mirror's bizarre surface, which curves and bends in different directions.