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Another Mystery of Live Solved
Science >
There are many great questions in life: Why are we here? Are we alone? What is the purpose of life? Today, here, we will answer one of life's great mysteries --- What is the connection between the spring equinox and bad satellite TV reception?
Satellite television basically involves aiming a receiving dish towards a distant orbiting satellite that is transmitting television.
But here's a problem: If these satellites are buzzing around Earth at thousands of miles an hour, why do our dishes point in just one direction all the time? Answer: Some satellites are not moving --- from our point of view, that is.
The laws of physics tell us that the closer an orbiting object is, the quicker it will go around us. It's not unlike rubber duckies swirling down a drain. The duckies closer to the drain move at a good clip compared to the duckies farther out.
Satellites which orbit just hundreds of miles above the surface of the earth, like the Shuttle or the Space Station, take only about 90 minutes to orbit the entire planet. Satellites at higher orbits take hours to accomplish this. Keep going and you'll eventually get to a distance --- 22,300 miles to be precise --- when an orbiting satellite takes a lazy 24 hours to make it once around.
But wait! Doesn't the Earth take 24 hours to spin around one time. Ba-da-bing! So a satellite 22,300 miles above the Earth going from west to east is "in sync" with us below on the Earth's surface.
Put that same satellite directly above the equator and it will appear not to move at all --- not a wobble. We call this a geosynchronous orbit. This one orbital altitude allows "stationary" satellites to keep a constant eye on a region's weather, or on an enemy, or to broadcast television to your home.
That is why your television dish is pointed to one spot in the sky. Now what's this all got to do with bad spring equinox reception? Thinking cap time!
Imagine the world as an orange. Cut the orange through the middle where our equator would be. Take off the top half. Lay a vinyl record --- remember those? --- on the exposed bottom half. Replace the top of the orange. It should now look like an orangey planet Saturn with a black ring system. The black record symbolizes the Celestial Equator, an imaginary extension of our own equator that radiates out into space, forever. Astronomers use it as part of the coordinate system for finding things in space.
From the point of view of someone on Earth our sun crosses this Celestial Equator twice a year --- at the equinoxes. In the spring it crosses from south to north. Just the opposite happens at the fall equinox.
Now the satellite connection.
Remember that geosync satellites orbit directly above our equator. If we could with special eyes see all the geosync satellites we would see them all lined up, day and night, in a huge arc across the southern skies --- right on the Celestial Equator.
Well, on the 20th this month the Sun will cross said Celestial Equator as we celebrate the first day of spring. Unfortunately though, in and around the 20th, the blinding, high-energy sun will also be directly behind many of those geosync satellites for some part of the day. Many of our dishes will then be dazed and confused and we may experience a "temporary disruption of reception."
Whew! Another Mystery of Life solved. Sleep well tonight!
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Posted by Administrator at 2002.03.16 03:07 PM | Comments (0)
