Added 1 new A* page:Good news! You won't have to keep an eye out for a new page from me on Monday! Because I'll be taking the day off to catch a holiday party with friends. >_> Durn these holidays, anyway! Well I hope you're getting through them more or less intact if you're having them. I will be back to work on a new page on *Tuesday.*
Speaking of bringing stuff back, did you know that a few months ago, scientists at the Australian National University broke the distance record for a tractor beam (BBC)? This is a little less impressive than it may sound if you're thinking of classic sci-fi tractor beams—in this case, the new record is 20 centimeters. That was 100 times further than the previous record, though! And actually the scientists said it could have worked over "meters," but their lab wasn't large enough. So there! I'm just gonna quote the middle section of the article since it does a great job of explaining what this real-life "tractor beam" stuff is all about:
Previous tractor beam experiments used the momentum of light particles (or photons) to impart motion. But this latest device relies on the energy of the laser heating up the particles and the air around them.
The researchers used a so-called hollow laser beam in a laboratory at the Australian National University (ANU) in Canberra. The laser is bright around the edges and dark at its centre.
They then used it to manipulate hollow glass spheres about a fifth of a millimetre across.
The particles are trapped in the dark centre of the beam. Energy from the laser hits the particle and travels across its surface, where it is absorbed creating hotspots on the surface.
Air particles colliding with the hotspots heat up and shoot away from the surface, which causes the particle to recoil in the opposite direction.
By changing the laser beam's polarisation (the direction in which the light waves vibrate) they were able to move the position of the hotspot to manipulate the glass spheres. |
Sounds a little like cheating, but technically it is a beam and it is tractoring (that's a technical term, right?) things around, uh or at least causing them to move around. And I think we can trust science to come up with some really useful applications of this sort of thing, probably more useful—if perhaps less dramatic—than holding spaceships in place. Oh actually the article lists a few potential uses, you should go read it!
|
