# Most Powerful Laser Ever



## Zubi-Ondo (Jul 3, 2008)

In the Aspiring authors thread we were talking about "sounds in space" and the topic wandered to lasers, and how you can't see them until they hit something. I was doing some research about that when I came across this url:
Powerful laser is 'brightest light in the universe' - space - 09 April 2008 - New Scientist Space

They say it produces light more powerful than anything in the universe since the time of the "big bang" which is quite a claim. It only lasts for "one-tenth of a trillionth of a second", so that's obviously part of how they get away with it. What does anybody think?

Also, I was wondering if the reason you can't see lasers like you can a flashlight is because it's considered "coherent" light, but I can't find a direct answer to that. 

 - Z.


----------



## Anthony G Williams (Jul 3, 2008)

I don't think there is any difference in this respect between normal and coherent light. Both of them will only become visible when they hit something. In atmosphere, they hit particles in the air (which is why torch beams are especially visible in mist - they hit the water droplets). But if there's nothing to hit, you won't see them - unless they're pointed at your eyes, in which case you certainly will!


----------



## Nik (Jul 8, 2008)

Um, IIRC, lasers may be more difficult to see under some conditions because refracted light from mist will only come back at one set of angles, instead of white light's rainbows...

Also, a laser generally has a very narrow beam, so will illuminate a much smaller cross-section and far fewer particles.

Astronomers can use lasers to make 'artificial stars' to track and correct for atmospheric disturbances. They really, really do not want scatter beyond that very narrow beam...

Um, pulsed laser power is fine, but what's the record for sustained beams ?? Not trying to diminish those mega-pulse whatsits, I'm reminded of cheap hifis that claim '32 Watts' PMPO, but only, um, 2 Watts RMS...


----------

