13 April 2006

The only constant is my light prose

Filed under: Ponderings

On to the speed of light.

Now as most of you know (or all of you who read my post below about my opinions about the metric system) the speed of light is the cornerstone of astronomical knowledge. Nearly everything we know, or think we know, about the universe outside of our very small little corner of it is based on our measuring how fast light travels.

For those of you who don’t remember your 9th grade physics class (myself included, but I know this from other sources), the speed of light is roughly 300,000 kilometers per second (or 186,000 miles per second for you imperial measurement aficionados).

Now, for a little science…sorry, I’ll be brief, but it’s essential to the rest of our little chat here. Time for redshift.

From Wikipedia: “In physics and astronomy, redshift is an observed increase in the wavelength and decrease in the frequency of electromagnetic radiation received by a detector compared to that emitted by the source. For visible light, red is the color with the longest wavelength, so colors experiencing redshift shift towards the red part of the electromagnetic spectrum. The phenomenon goes by the same name even if it occurs at non-optical wavelengths (in fact, longer-wavelength radiation “redshifts” away from red). The corresponding shift to shorter wavelengths is called blueshift.

Astrophysical redshift occurs, for example, when a light source moves away from an observer in an analogous but not equivalent fashion to a Doppler shift of sound waves from a receding object. Redshift is used as a diagnostic in spectroscopic astrophysics to determine information about the dynamics and kinematics of distant objects. Most famously, redshifts are observed in the spectra from distant galaxies, quasars, and intergalactic gas clouds to increase proportionally with the distance to the object. Astronomers consider this to be one of the major forms of evidence that the universe is expanding, supporting the Big Bang model.”

Okay, that wasn’t so bad, was it?

So here’s my point. This is all well and good and we all have a nice orderly universe based on one simple fact, that the speed of light is constant. But is it? I say no, and have lots of people who agree with me. Several studies have been done to slow down, and even stop, beams of light. Last year for instance IBM created a computer chip that could slow down a beam of light. The chip, called a photonic silicon waveguide, is a piece of silicon dotted with arrays of tiny holes. Scattered systematically by the holes, light shown on the chip slows down to 1/300th of its ordinary speed of 300,000 kilometers per second.

If a bunch of monkeys who only recently gained the ability to travel 400 kilometers above their own planet can stop a beam of light in its tracks, how can we be so sure that there are not natural phenomenon that do the same thing? In 1999 Harvard University researchers discovered that when atoms become packed super-closely together at super-low temperatures and super-high vacuum (like space for instance?), they lose their identity as individual particles and act like a single super- atom with characteristics similar to a laser. Such an exotic medium can be engineered to slow a light beam 20 million-fold from 186,282 miles a second to a pokey 38 miles an hour.

So what does this mean to me, I hear you cry.

One simple thing. If the speed of light is not constant everything, and I mean everything, we know about distances in space is wrong. The universe could be 10 or 100 or 1,000,000 times bigger, or more importantly smaller, than we think. It also may be a lot older, but more likely a lot younger, than the 18 billion or so years old current thought holds.

Now don’t get me wrong, I’m not leading up to saying that the universe is 5,766 years old, as Popes and Rabbis would have you believe. All I’m saying is that things are probably not what we think they are up there.

And that’s pretty cool.

Leave a Reply