Tuesday, November 1, 2011

Allow me to draw you in... to the new host of Handsome Science!

Hello, Readers!

Welcome to handsomescienceblog.blogspot.com, the new location for all your good-looking science needs!  I dropped Tumblr simply because I don't know nearly enough of the html coding language to modify my page to my liking, and what I want Handsome Science to be wasn't quite possible with any of the templates I'd found.

Blogger, run by Google, on the other hand, is extremely customizable, even for someone with zero coding ability.  Essentially, if you can create a Word document, you can set up a blogspot blog.

(Blog blog blog.  There, now that word has temporarily lost all meaning for me.)

So, about my hiatus.  I'm afraid I haven't been able to buckle down and write much since gaining gainful employment.  I will try to get up early enough to write, but I think I will stick to a more reasonable goal of two or three posts a week instead of five.  My brain has a silly tendency to give up if I can't reach a goal instead of doing my best and falling a bit short.  So I'll set a more reasonable goal and see how that goes.

There was another problem I experienced two weeks ago, a kind of hurdle I set up that I just couldn't jump over.  I was working on "How We Know:  The Periodic Table," but I couldn't for the life of me find any online resources that explained how John Dalton came up with the first atomic masses.  I could have guessed, but that's not what we do here.  So I'll set that aside in favor of something I can talk about:

Tractor beams!

In the first ten minutes of the very first Star Wars movie in 1977, captivated audiences were treated to a plethora of grandiose science fiction tropes including an alien planet, two spaceships (one truly MASSIVE on that big screen), laser cannons, and a tractor beam.  Later in the film, another, even more powerful tractor beam had to be disabled by an old Jedi Master for the heroes to escape an unthinkably large planet-destroying space station.

(Yes, I am recalling these scenes from memory.  So sue me.)

With that in mind, check this out:

Nasa examines 'tractor beams' for sample gathering

Yes, just as Star Trek's fanciful communicators were realized as cell phones less than a decade later, so have tractor beams been a known reality in science and engineering since at least the 1990s.  Here's Wikipedia's entry on the subject.

First off, what is a tractor beam?  Simply put, it's a beam of energy (like light) that pulls on matter (like air molecules), in a manner similar to the effect of gravity*.  Light is already known to have a pushing effect on matter.  In fact, one idea for long-range space travel is the "solar sail" that uses sunlight and laser beams to push on a giant sail of a mirror-like material.  How does that work?  Well, light is an odd beast.  It's actually made of particles called photons, and while these photons have no mass, they add their energy to the sail when they hit, exerting a small amount of force.

Pushing with light is one thing, but pulling?  Well, the tractor beams we're talking about are lasers.  And one thing to know about a laser is that while it looks like a beam to us, it's really a wave of photons weaving from side to side.  One type of tractor beam uses the "optical tweezer" effect of this wave structure to trap particles in the "waist" of the beam (remember, the waves are three-dimensional, so they have bulges and thin waists instead of peaks and troughs).  Why these particles are trapped in laser beam waists has do with quantum physics effects (that I can't say I understand), which is very important for research and engineering, but not for us right now.  What's important is that it works, and once you have trapped a particle, you can alter the laser beam to bring the waist closer to the laser emitter, and "pull" the particle.

The BBC article mentions two other types of laser that have tractor beam effects:  the solenoid (coil-shape) beam, and the Bessel beam.  They operate on similar principles; the Bessel beam operates at greater distances, and the solenoid uses its spiral shape (instead of bulges and waists) to pull objects, like you see in some vending machines (don't you hate it when it snags your chips on the coil?!).

It's going to be a long time, I imagine, before we see tractor beams pulling on spaceships, but not long at all before we see them on our own space probes and landers, scooping up atmospheric samples with beams of light.

*Gravity is a weird force, I'd like to point out.  It is considered one of the universe's four fundamental forces, the others being the strong nuclear force, the weak nuclear force, and electromagnetism.  These other forces can be positive or negative, and are all much more powerful than gravity.  But gravity only goes in one direction, and nobody really knows how it works fundamentally.  Einstein's theories suggest that gravity isn't a force, but a side effect of mass on the fabric of space-time:  objects essentially warp space around themselves, which causes other objects to move toward them.

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