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Uploaded:2017-02-18
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Did you know you can watch the big bang on an old TV any time you want?

Hosted by: Hank Green
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Sources:
http://electronics.howstuffworks.com/tv.htm/printable
http://www.bbc.co.uk/schools/gcsebitesize/science/aqa_pre_2011/radiation/the_electromagnetic_spectrumrev6.shtml
http://www.bbc.co.uk/schools/gcsebitesize/science/ocr_gateway/home_energy/data_transmissionrev3.shtml
http://www.universetoday.com/25560/the-switch-to-digital-switches-off-big-bang-tv-signal/
Hank: If you've ever used an old-school radio or TV, I can't believe we have to that now, you're probably familiar with static: that crackly, fuzzy noise coming from the speakers or the random white dot pattern popping up on the screen. Whether it's on the radio or TV, this static shows up for the same reason, unwanted electromagnetic waves interfering with the real signal. And some of those waves go all the way back to the Big Bang.

TV and radio antennas receive information from a broadcasting tower via electromagnetic waves, specifically radio waves. But there are other waves in the atmosphere that accidentally get in the way. Lightning storms release large bursts of radio waves, and these waves interfere with the signal. The interference means your device ends up receiving a wave that's slightly offset from the original. This messed-up signal will correspond with some random sound or pixel, so you hear a random noise or see a small glitch. 

Even when there's no lightning, you still receive some noise from other sources, like radiation from other electronics or the radiation streaming out from the Sun. You'll even pick up some of the radiation left over from the Big Bang, called the cosmic microwave background radiation.

Back in the day, if you tuned your TV so it was between broadcasting channels, then you would really notice those other sources of radiation, they would create random noise and changing pixels on your screen. But modern day devices don't have that problem, mainly because they mostly use digital signals instead of analog signals.

Digital signals also store information in an electromagnetic wave, but they only use particular, discrete values. And if interference offsets that wave slightly, the TV can just guess what wave it was supposed to be and correct it. It takes pretty strong interference to change the wave enough to alter the TV's interpretation, so you're much less likely to end up with noise.

For the most part, digital TV signals have replaced analog around the world, but analog radio is still being used in lots of places, Like probably your car. So if you have an analog radio and it tends to get crackly, just remember: you're getting a little glimpse into lightning storms, the majesty of our Sun, and even into the beginning to our universe itself.

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