weirdness in my rear window
 

Has anyone else seen this in their rear window? It seems to be more visible during dusk and I'm just curious what causes it. Also curious if it means there's something wrong with the window. It actually blocks your view at certain times of the day. During the middle of the day, you can't see it.
http://forums.pelicanparts.com/uploa...1234307955.jpg
http://forums.pelicanparts.com/uploa...1234307977.jpg
http://forums.pelicanparts.com/uploa...1234307991.jpg

Here it is on a sunny day with no weirdness visible.
http://forums.pelicanparts.com/uploa...1234308494.jpg

My targa has the same thing. Don't know what's causing it.

Most cars have this phenomenon. i think it has to do with either the tinting or the laminated layer of plastic on safety glass.

you will see this on the windshield of most oncoming cars if you are wearing polarized glasses.

i assume targas have safety glass on the rear too. more angles = more refraction make it show to the naked eye.

it looks like the marks on tempered glass, but normally you would only see them when looking through a polarised lens (eg polarised sunglasses).

edit: ah, teenerted, you beat me to it

polarized auto glass is what you have, and so does mine:

It's because it's tempered glass and your using a polarizing (glare removal) coated lens on your camera. Look at your car with polarized sunglasses and take them off, you'll see the same effect.

I've noticed the same thing with mine, but only evident when wearing polarized sunglasses. Tempered glass. I notice it on my wife's car too

All automotive glass is of the tempered (breaks only into a kazillion tiny pieces) or safety (only cracks, won't break) variety. I believe thicknesses are even set to make sure the average noggin breaks or cracks the glass before the noggin cracks open.

Big shards of flat plate glass windscreens used to be a major cause of injury and death with the low speed collisions of early automobile travel.

Thanks for the interesting feedback. I do have to say that I see it with my naked eyes and not just through the camera. It even raises questions from neighbors that come over to chat. I don't even know if I own a pair of polarized sunglasses.

Should I worry about it?

Again, same thing, I can see the "weirdness" on my glasses with naked eye. I wouldn't worry about it.

Sunlight can be polarized at certain times, when it's dusk or dawn, as you mentioned. At those times (and angles) your eyes can see what others see through the polarized sunglasses.

If you look carefully at any tempered glass you can see this. Part of Special Effects for movies when breaking glass (they break it by putting to "glass breakers" which are a mini metal cannon with a squib (explosive charge) in it that rams out a small steel rod to hit the glass. They always use two, to split the glass evenly from both sides, and as a backup. Anyway, you want to visually inspect the glass with polarized glasses to gauge the completeness of the temper. A poor temper means the stunt man may be going through shards of glass otherwise.

A piece of Hollywood trivia.