We can see some of the other planets from the Earth. They look like stars, but unlike the stars, they ‘wander’ across heaven. Indeed, the word ‘planet’ means wander. The easiest planet to recognize, and the brightest, is Venus. It shines

The places where astronomers work and make their observations are called observatories. Mostly, these places are located on the hill tops, away from the big cities and it is done with only one reason that is the environment including air is much

When we want to send spacecraft into space, we somehow have to beat gravity, which tries to pull it back to Earth. We can beat gravity by speed. We shoot the craft into the sky so fast that the Earth cannot pull it back. The speed we must give a

What kind of engine do we need to make a spacecraft travel at 28000 kilometres an hour? Ordinary engines, like the petrol engine used in cars, are not powerful enough by half. Nor are the jet engines used in aircraft. Even the fastest jet planes

What happens when you jump up into the air? You will definitely come back to ground. It is only because of Earth that a jumper when it goes up comes back on the ground. What happens when an apple is ripe? It falls from the tree down to the ground.

On 4 October in year 1957, a powerful rocket blasted off a desolate launch site in southern Russia carrying a tiny aluminum sphere. After about fifteen minutes this sphere began circled around the Earth, 500 kilometres (300 miles) high. As Earth

People began star-gazing thousands of years ago. One of the reasons they did so was to work out a calendar, so that they could organize their lives better. A calendar is a way of dividing up time so as to fit in with the seasons. By studying the

Since early days, the speed, efficiency and cheapness with which signals may be sent across the world have improved greatly. Each day, millions of people use the telephone to speak to people on the other side of the world, just as easily as if

Long distance communications have improved greatly in the 150 years since Samuel Morse first used his electric telegraph. Today, messages are just as likely to be sent through space as along wires. Using a network of satellites orbiting high above