What Is The Sun?
What is expected to happen to the Earth after 6 billion years?
Our Sun is a star, just like all the other stars in the sky. It only seems bigger and brighter because it is so close to us.Our Sun was born 5 and a half billion years ago from a swirling mass of gases.As the gases grouped together the gravity became greater dragging more and more gases into it and the planets formed around this whirlpool. Eventually the gases became so condensed; the heat and pressure became so great that a nuclear reaction took place.Hydrogen gas, which is what makes up 70% of the sun, began turning into helium gas. This reaction caused the sun to ‘ignite' and that is what we see today.The Sun is not ‘burning' it is this massive nuclear reaction that makes it hot and bright. It is using up 4 million tons of mass every second. But there is a lot more to the sun than meets the eye.The Sun is so big it makes up 99% of the material in the Solar system. The visible yellow sun you see in the sky is only a part of what makes up the sun.If we could take a slice through the sun we could see it is made from many different layers.The central core is where the reaction of hydrogen into helium takes place. The temperature here is 15 million degrees centigrade or 27 million degrees Fahrenheit.This heat and reaction takes a long time to make its way to the surface by which time it has ‘cooled' to a mere 10 thousand degrees Fahrenheit or 6 thousand degrees Centigrade.But the surface of the Sun is not stable, there are constant changes taking place.The most noticeable are Sunspots. These are slightly cooler areas of the sun caused by electrical storms bursting up from the centre and exploding on the surface.Sunspots have been known to come and go in an eleven year cycle. There are periods when there are no sunspots on the surface, to periods when the Sun is freckled with masses of them.These sunspots burst onto the surface causing giant flares known as solar prominences. Huge flares stretching out into space being thousands of times bigger than the Earth.The Sun has an atmosphere. It is known as the corona, and as it is a million times less bright than the surface of the Sun. It is only visible during a total eclipse.Like the Earth, the Sun rotates but at different speeds across its surface. At the equator it rotates once every 25 days but at the poles it takes about 36 days.The Sun emits radiation particles, these particles are known as the solar wind. It is when this solar wind hits the Earth it is drawn towards the magnetic north and south poles and reacts with the Earths upper atmosphere and causes the Aurora. Coloured lights that flicker across the sky at the extreme north and south poles, they are almost constant at the north and south poles. Our Sun is a middle aged star. It is not particularly bright and it is far from being very big. There are other stars that dwarf our sun.So what happens to a star at the end of its life? Some stars explode violently in a supernova. But this will not happen to the Sun. Instead, in about 6 billion years our Sun will use up all of its hydrogen, then it will begin to swell. It will engulf the orbit of Mercury, Venus and the Earth, completely swallowing them up.Then gravity will make it condense, and it will collapse upon itself, its light will go out and it will become a white dwarf. Surrounded by a planetary nebula. There are many examples of planetary nebula throughout the universe. And a passing alien will wonder, was there ever a planet with life on it here?But don't worry you've still got time to get a sun tan. For more intriguing looks into the universe, check out our other videos at VideoJug.