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: http://www.naic.edu/~phil/misc/flatwillie.html
Дата изменения: Thu May 27 18:45:25 2004 Дата индексирования: Tue Oct 2 04:02:05 2012 Кодировка: Поисковые слова: universe |
Puerto Rico is an island about 1000 miles south of Florida. It is close to the equator so it never gets very cold. When Flat Willie arrived in May it was 80 degrees and raining. He really liked the warm weather but the rain kind of made him droop. Unfortunately for him, it looks like it's going to be a droopy visit since it has been raining every day for the last month. Willie took a quick trip into the town of Arecibo to buy an umbrella. Since the people in Puerto Rico speak spanish, Flat Willie had to brush up on his spanish language a bit. After a few days of practice he was speaking spanish just like a native.
The Arecibo Observatory is a radio telescope run by Cornell university for the National Science Foundation. It is the largest single dish radio telescope in the world. It has a main reflector (or dish) sitting in the ground that is 1000 feet across. It covers about 20 acres. This dish is just an oversized version of the tv satellite dishes that you see on the top of some peoples houses. Instead of pointing at satellites that carry tv stations, this radio telescope looks out at the atmosphere, asteroids, planets, stars, and galaxies to learn more about how they work.
When you look at a star at night, you see the light with your eyes that the star gives off. It turns out that stars also emit radio waves. These radio waves are just like (the same frequencies) as the signals from radio and tv stations (although we haven't picked up Sesame Street from any stars yet..). We don't see these radio waves from the stars just like we don't see the radio waves from tv and radio stations because our eyes are not sensitive to this frequency. But they're still there to be studied.
After resting up a bit (and gluing Willie to some cardboard so he wouldn't droop so much) Flat Willie took a tour of the observatory with phil and luis murray. The first picture shows Flat Willie standing in front of the control room looking out at the telescope. The telescope has two parts: the reflector or dish at the bottom of the picture and the gregorian dome (the round ball) at the top of the picture. Radio waves that come from a star bounce off of the dish and head up into the gregorian dome at the top of the picture. Inside the dome are receivers that record the radio waves from the star so scientists can figure out how the stars work. The dome can move up and down along a track and spin around the ring you see. This lets it follow a star across the sky. To give you an idea of the size of things: it is about 500 feet from the bottom of the dish to the top of the dome (that's the height of a building with 50 floors). The dish at the bottom is 1000 feet from 1 side to the other and the whole things takes up about 20 acres.
In the first picture, it looks like Flat willie was stuck on a branch. The second picture shows that this branch is actually the arm of Luis Murray (that's Luis on the left of Flat Willie). Luis is the official Flat person tour guide at the Arecibo Observatory. Behind Flat Willie you can see the dome with the hole in the bottom (that's where the radio waves go in). The whole thing is suspended from the platform which is the triangle structure above it. If you want to go up to the platform you either walk along the catwalk (the bridge looking thing at the top left) or you can ride the cable car that gets pulled along the cables that you can see going up to the platform right next to Willie.
Since willie said that he wasn't afraid of heights, we decided to head up to the platform in the cable car. You can't go up to the platform unless you have the correct safety equipment. We checked to make sure that Willie had on his safety boots and then we got him a hard hat to wear. The third picture shows Phil with Flat Willie in the cable car getting ready to head up to the platform. What a ride it was! The only problem was that Phil had to hold on pretty tight to Flat Willie on the ride up. Willie kept wanting to hand glide down to the dish (I told him maybe next time).
After checking out the platform, the three of us went down to get a closer look at the dish. The fourth picture shows Luis and Willie on the edge of the dish. The dish is made of thin aluminum panels that are suspended above the ground by cables (that's one of the cables in front of Luis). The other side of the dish is 1000 feet away.
After all this touring around willie wanted to take it easy and just hang out a little. The fifth picture shows Willie "hanging out" on the gate that leads down to the dish. It took Luis and Phil a while to convince Willie that we'd better head back before it started to rain again.
Hopefully one of these days the other Will (the unflattened version) will show up at the observatory with his sisters (besides Flat Katie, there is a Flat Ally waiting to get to second grade so she can come visit Arecibo). An old picture of the trio shows them pondering the meaning of life while slurping down some ice cream. Ally (on the right) looks like she's got it pretty much figured out...
More information about the telescope can be found at the Arecibo observatory home page or try phil's home page .