Do not point laser at remaining eye.

Wow! That pic is so freakin’ cool!

These are two diferent types of energy:the laser is light energy the lightning is electricity .Now the laws of Physics say that energy can be changed from one form to another ,but not like this. You could use a laser to heat water and use the steem to power an generator that turns light energy to heat energy to electricity.

Well, this is right, as far as it goes, but if you go a bit more fundamentally, light and electricity are both phenomena of the electromagnetic force.

A sufficiently powerful laser will ionise the air through which it passes, creating a line of plasma (well, strictly speaking it’s only a plasma if all the electrons are stripped off the atoms, but air only needs a few electrons to be knocked loose to suddenly become a much better conductor). If the clouds have built up some electrical charge (as happens in thunderstorms), then the laser will indeed trigger lightning, as the charge in the cloud suddenly encounters a low-resistance path to Earth.

And this is to say nothing of the fact that some light show presenters SCAN THE CROWD with multi-tens of watt beams of this sort, such as here: http://www.youtube.com/watch?v=Qus9rv2V2fg

The eye injury reports from concertgoers at these sorts of events are somehow shockingly rare, given the number of people exposed every year. Still, I absolutely do not trust my eyes to some nobody who runs light shows on the weekends for spare change, and would leave any establishment where audience scanning was occurring without a second thought. IMMEDIATELY.

The scary thing is, that same page where you can purchase this thing has absolutely no warnings on it (other then “laser stings bare skin,” which is up there with features rather then a warning).
It’s clearly marketed as a laser pointer (“for teachers, doctors, professors, etc”) that is “easier then pointing with your hands”. Oh, there’s also a close- up of the laser with a caption “laser comes out here”. I s**t you not.

I think I’m going to get some laser-protective goggles and wear them in public all the time, just in case.

Let’s take a 20W (this seems to be a typical power for such things) laser guide star operating at the sodium doublet wavelength of ~589 nm (the yellow color you see in street lamps) as an example. Usually the laser is launched not in a pencil-lead thin beam as you see from a laser pointer, but from a telescope of several tens of cm aperture, let’s use 30 cm as an example. Now, the beam area of such a laser is going to be ~700 cm^2, giving the intensity at any one point inside the beam of a mere 29 milliwatts per square cm. Add to this fact that a dark-adapted, dilated pupil has an aperture area of only half a cm (~8mm dia), and neglecting path losses which it must be said are likely non-trivial, the absolute maximum amount of power that can reach the retina is now down to 15 milliwatts. Three times the power output of a typical 5 milliwatt laser pointer.

Add to all of this that laser guide stars are fixed to point at one spot on the sky (sky motion is trivial and can surely be neglected) and the speed of the plane must be at least, say 100 mph (4,500 cm/s), and the pilot in a plane unfortunate enough to fly through the beam while staring directly into it will have a maximum retinal exposure time of a whopping 7 milliseconds!

The amount of energy that can be deposited on a person’s retina in that amount of time at that power level, is simply trivial. At most, the pilot will experience a quick flash blindness of the kind you get after seeing a camera flash go off and the effects will almost certainly fade within a very short period of time. Beams of this intensity, used for this purpose, are complete non-hazards for both plane structural integrity and pilot eyesight.

However, I’m not sure if Phil is aware of it, but there ARE LASERS that are used to trigger lightning (with varying levels of success) which were recently in the news. These lasers are MOST DEFINITELY NOT eye safe by any means, being pulsed lasers in the TRILLIONS of watts range sufficient to ionize air.

I would enjoy this picture as a poster, Who owns the copyright?

Also, this picture definitely earns a running in the “Most Badass Photo of the Year” award. All that’s missing is Chuck Norris jump-kicking a machine gun-toting bear.

My point about damaging the aircraft was from the idea that when I used a 1 Watt laser, I could pop balloons and burn paper within a fraction of a second. A beam 20 times that power would be more damaging. I wasn’t thinking of a plane passing through the beam so much as the beam being held in one place, so I can see what I wrote is misleading. I added some weasel words to amend that.