• In the 1770s, scientist Joseph Priestley, through experiments on mice found that air contained something important that animals needed if they were to live. He called this vital substance phlogiston. It was only later in the 1780s, that Antoine Lavoisier found that Priestley's phlogiston was a gas, which he named oxygen.
• 3/4 of all the air in the atmosphere is contained in the troposphere. Flying through the troposphere can be very bumpy, as anyone who has flown by modern aircraft will tell you! To solve this problem, modern passenger jets fly up high where the air is still and clear, above the clouds in the stratosphere.
• At sea level, each litre of air contains about 25,000 million million million molecules of gas.
• Antarctica is the coldest, windiest and driest continent on Earth. Cape Denison (67ºS, 142ºE) on the south coast of East Antarctica is the windiest place in the world, with an average annual windspeed of 68 km/hr.
• Because distances in space are enormous, Astronomers measure them in "light years". One light year (LY) is the distance light travels in a year - 9.46 million million km (5.88 million million miles). After the Sun, the nearest star is Proxima Centuri that is 4.3 LY away.
• Astronomers can tell the temperature of a star by its colour and brightness. The Sun is a yellowish star and is thought to have a temperature of about 5,500ºC. This compares with a bright blue-white star which has a temperature of about 30,000ºC.
• The surface of the Sun is constantly moving, like a stormy sea. This is because its surface is a boiling mass of very hot gas.

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