THE SUN :
1. WHAT IS THE SUN?
Ans: The Sun is an average star, just like countless others in the universe. It formed from gas left behind after an earlier, much larger star blew up and now, in middle-age, burns yellow and fairly steadily – giving the Earth daylight and remarkably constant temperatures. Besides heat and light, the Sun sends out deadly gamma rays, X-rays and ultraviolet, as well as infrared and radio waves. Fortunately we are shielded from these by Earth’s magnetic field and atmosphere.
2. WHAT IS A SOLAR ECLIPSE?
Ans: A solar eclipse is when the Moon moves in between the Sun and the Earth, creating a shadow a few hundred kilometres wide on the Earth.
3. WHAT MAKES THE SUN BURN?
Ans: The Sun gets its heat from nuclear fusion.Huge pressures deep inside the Sun force the nuclei (cores) of hydrogen atoms to fuse together to make helium atoms, releasing huge amounts of nuclear energy.
4. WHAT IS THE SUN’S CROWN?
Ans: The Sun’s crown is its corona, its glowing white hot atmosphere seen only as a halo when the rest of the Sun’s disc is blotted out by the Moon in a solar eclipse.
5. HOW HOT IS THE SUN?
Ans: The surface of the Sun is a phenomenal 5500″C, and would melt absolutely anything. But its core is thousands of times hotter at over 15 million C.
6. WHAT IS THE SOLAR WIND?
Ans: The solar wind is the stream of radioactive particles constantly blowing out from the Sun at hundreds of kilometres per second. The Earth is protected from the solar wind by its magnetic field, but at the Poles the solar wind interacts with Earth’s atmosphere to create the aurora borealis or northern lights.
7. HOW OLD IS THE SUN?
Ans: The Sun is a middle-aged star. It probably formed about 4.6 billion years ago. It will probably burn for another five billion years and then die in a blaze so bright that the Earth will be scorched right out of existence.
8. WHAT ARE SUNSPOTS?
Ans: Sunspots are dark blotches seen on the Sun’s surface. They are thousands of kilometres across, and usually occur in pairs. They are dark because they are slightly less hot than the rest of the surface. As the Sun rotates, they slowly cross its face – in about 37 days at the equator and 26 days at the Poles. The average number of spots seems to reach a maximum every I| years, and many scientists believe these sunspot maximums are linked to periods of stormier weather on Earth.
9. WHAT ARE SOLAR FLARES?
Ans: Flares are eruptions from the Sun’s surface that fountain into space with the energy of one million atom bombs for about five minutes. They are similar to solar prominences, the giant flame-like tongues of hot hydrogen that loop 32,000 km into space.
10. HOW BIG IS THE SUN?
Ans: The Sun is a small-to-medium-sized star 1,392,000 km in diameter. It weighs just under 2,000 trillion trillion tonnes.