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Look, aliens from Carina, we don't know you AREN'T going to invade, or that you even exist, and we can't be too careful, OK? https://www.syfy.com/syfywire/eat-lasers-carina-nebula
2/ Yes, those are in fact giant lasers! Astronomers use them to create artifical guide stars to improve the resolution of their telescopes. The tech behind this sounds like Star Trek, but it's *real*.
3/ The lasers excite sodium atoms high up in the atmosphere. These glow brightly, looking like stars from the ground. By measuring how the atmosphere distorts them astronomers can compensate for turbulence in the air that smears out the images.
4/ The shape of the blurred stars are measured many times per second. Then a computer calculates what shape the mirror in the 'scope needs to be to correct for that, focussing the light back into a dot. Pistons on the back of the mirror then *deform it to that shape*.
5/ This is done constantly, many many times per second. This is called "adaptive optics" and the results are amazing. Big 'scopes on the ground can get Hubble-like resolution, see incredibly small details on astronomical objects.
6/ This GIF from the Keck observatory shows how much better the center of the galaxy looks before and after AO is switched on.
7/ Sometimes this can be done with stars that happen to be in the right spot in the sky to use, but that doesn't happen all the time, so lasers are used to make artificial stars. They're so powerful that software is used to switch them off if any airplanes are nearby!
8/ Once I was out at night and an observatory was using green lasers to get the distance to a satellite. I could *see* the beams heading into the sky, converging on a single point. It was eerie and beautiful. The lasers I talk about in my article though are MUCH more powerful.
9/ They're 22 Watts each. That's an immense amount of power for a laser. It would set fire to wood, for example. So they're used *carefully*. But they're use is very important to astronomers, allowing incredinle images to be taken from the ground.
10/10 I know y'all like astronomy because of the amazing concepts and cool photos. But *how* we do it is pretty amazing too. And the photos f that can be pretty intense, too. :)
And of course: Lasers! Pew pew! https://www.syfy.com/syfywire/eat-lasers-carina-nebula
And of course: Lasers! Pew pew! https://www.syfy.com/syfywire/eat-lasers-carina-nebula
