Wednesday, September 19, 2007

Do the Wave

We humans can’t see very well when we look far far into outer space. Sure, telescopes give us a glimpse at deep space, but we can only learn so much when we just use our eyes. Luckily there are plenty of other options when it comes to detecting electromagnetic radiation from outer space. Visible light is only one kind of electromagnetic (EM) radiation. We can broaden our view of the universe by using new-fangled instruments that will detect photons with various wavelengths. A photon is basically a little packet of energy. We call photons “packets” because you can’t really call them a particle and you can’t really call them a wave since they behave like both. They can be shot off from an atom the way an electron might be, but we can see them as light, with wavelengths that correspond to different colors. You could say that photons go both ways. They’re swingers, man.

Much like delicious ice cream treats, electromagnetic radiation comes in all kinds of different flavors. We’ve got photons with long wavelengths which make-up things like radio waves, micro waves, and colors like reds and oranges. On the other end of the spectrum we’ve got waves with really short wavelengths like gamma rays, X-rays, and colors like violets and blues. When we talk about wavelengths, we’re talking about the distance from peak to peak OR trough to trough on a wave.

Any wave (EM, ocean, crowd at football stadium) will propagate with a speed that is the product of its wavelength multiplied by its frequency:

velocity = wavelength * frequency

All types of waves in the electromagnetic spectrum travel at the speed of light which is 3 x 10^8 meters per second. That’s 670 MILLION miles per hour (if I did my math right). Crazy fast. So fast, in fact, that nothing travels faster than the speed of light. Yet.

A consequence of this whole traveling-at-the-speed-of-light thing is that the speed of light never changes. For our purposes, it’s a constant. This means that if you increase wavelength you have to decrease frequency and vise versa. So waves like gamma rays that have super small wavelengths have really high frequencies and are super duper energetic. Radio waves and Infrared waves with long wavelengths have lower frequencies. When we talk about frequency, we’re talking about how many waves hit you in a given amount of time. Where gamma rays are like “bam, bam, bam, bam”, Infrared waves are like “bam…………bam…………bam………….bam”.

As an aside here: you ever wondered why your car’s antenna is as long as it is? That’s because the wavelength of radio waves is about 100 centimeters – just about how long your car’s antenna is!

Please excuse me now. I have an appointment to receive a wedgie and be stuffed in a locker.

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