By Dave Bains

It may be useful to get to know a bit more about our neighbourhood. Earth is our home and we are in Sun’s neighbourhood. We will start with the earth. It is about 4. 5 billion years old. In old times, earth was thought to be the centre of the universe. In fact we are not the center of anything. We are in the Milky Way galaxy – a collection of stars. Even there our sun is about two thirds of the way from its center. Good to keep in mind our place in the universe. The Milky Way has billions of stars and there are billions of galaxies.

Our sun is a star.

How far is the sun? Pretty far!

Sunlight takes 8 minutes to get here even though it travels at an unheard speed of 300,000 kilometers per second!. When you look at the sunlight, it had left the sun 8 minutes earlier. It is 150 million kilometers or 93 million miles from earth. The universe is so huge, the light you see now from the most distant stars left there some 14 billion years ago. If you could ride the light, you can go around the earth 7 1/2 times in one second. How long you say your India flight was? Sound on the other hand travels a lot slower. That is why you see the lightning flash before you hear the thunder.

Earth just happens to be right distance away from the sun for life to have evolved.

Mercury and Venus are too near the sun, while in the other direction too cold or frozen .

Earth is about 13,000 kilometers across and 40,000 kilometers around. It goes around the sun at a speed of 30Km per second or 110,000 Km per hour. It spins around itself in 24 hours i.e. at a speed of 1670 Km/hr. This means you, I and everything is spinning around at about thousand miles per hour. We don’t feel it because everything around us is also moving with us.

Earth is a giant magnet. The temperature increases towards the centre to about 6,000 C, which is the same as at Sun’s surface. There is lot of molten rock and iron sloshing around. But at the centre it is solid due to the extreme pressure. There is a magnetic field around the earth which shields us from the sun’s harmful solar ‘wind’. The magnetic field deflects the solar wind away or else we would not be here. It is not a wind as such. It is a stream of charged particles from the sun.

You may have seen, at least on TV, the fascinating Northern lights. They ‘dance’ and change colour and hues. That’s the charged particles of the solar wind electrically exciting the earth’s atmosphere. There are Southern lights as well.

Until recently it was not known the delicate balance the earth’s environment is in. It was thought to be permanent. Mankind is rapidly affecting this equilibrium due to green house gases, greed and countries with ‘me first’. The earth knows nothing about countries or about life on earth. It needs to be shown respect, now!

Dave Bains is a Surrey-based writer.