My Science School

Artificial Satellites

Artificial satellites send signals. There are many different kinds of signals they send. Each carries a different type of information.

Some artificial satellites send their signals to radios, telephones, and television sets. These are called communications satellites. Ships, aircraft, and even some cars use navigation satellites to work out their location on Earth. Weather satellites take pictures of the movements of the clouds. Scientific research satellites send information about the universe. Scientists can use an earth observation satellite to look at Earth and find heavily polluted areas or damaged forests. Military satellites can send signals about the movement of missiles, ships, and soldiers.

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Telescopes make distant objects look bigger. Two main types of telescopes are refracting telescopes and reflecting telescopes.

A refracting telescope gathers light from a distant object and focuses it through two lenses. It has one big lens in front and a smaller lens you look through. The lens at the front usually has a bulge on both sides. It is thick in the middle and thin around the edges. This lens collects the light from a distant planet or star and forms an image of it in the telescope tube. The other lens, called the eyepiece, is like a very powerful magnifying glass. It makes things look much bigger.

A reflecting telescope uses a large mirror to collect the light, instead of a lens. The mirror is at the bottom end of the tube. The light from a star goes straight down the tube and strikes the mirror. Then the light is reflected up the tube. A smaller mirror reflects the collected light. The light comes out through a hole in the side of the tube, where the eyepiece is.

Picture Credit : Google