TV From The Sky

Did you know the cartoons on your TV might travel through space to get to you? High above Earth, metal objects called satellites spin through the sky like tiny moons we made ourselves. Some of them catch TV signals sent up from the ground and beam them back down to a dish on your roof. The signal travels 22,000 miles up to the satellite and 22,000 miles back down — and it all happens in less than one second. That is faster than a blink!

After this lesson you will be able to: explain what a satellite is; describe how a TV signal travels from a studio all the way to your home; explain what a satellite dish does; and describe how GPS satellites help people find their way.

A satellite is any object that travels in a circle around a planet. The Moon is a natural satellite — it has been going around Earth for billions of years. People also build satellites and launch them into space on rockets. Once they are in space, they keep circling Earth over and over without falling, a little like a ball on a string swinging in a big loop. Right now there are thousands of human-made satellites above us. Some take pictures of clouds to help forecast the weather. Some help airplanes know where they are. And some carry your favorite TV channels!

Here is the journey a cartoon takes from a TV studio all the way to your living room: 1. A TV studio records the show and sends the signal UP toward space using a huge dish antenna on the ground. 2. The satellite 22,000 miles up catches the signal and sends it back DOWN to Earth in a wide beam, like a flashlight spreading light. 3. A small curved dish on your house or building catches that beam. 4. A wire carries the signal from the dish into a set-top box, and the box turns it into the picture and sound on your TV screen.

GPS stands for Global Positioning System. It uses 24 satellites that circle Earth all the time, spread out so some are always above every part of the planet. When you open a map app on a phone, the phone quietly listens to signals from several GPS satellites at once. Each satellite says here is where I am, and here is how long my signal took to reach you. By listening to three or four satellites at the same time, the phone can figure out exactly where YOU are on Earth — even deep in a forest where there are no road signs! GPS helps cars, ships, airplanes, hikers, and even farm tractors know exactly where they are and where to go.