Frequently Asked Questions: Stars

Q. Why do stars 'twinkle'?
A. As the light from stars passes through the earth's atmosphere, it is refracted or 'bent' in different directions. This produces the 'twinkling' effect.

Q. If the stars in each constellation such as Leo the Lion are named in order from the brightest to the dullest using Greek letters, what are the first five letters of the Greek alphabet?
A. Alpha (α), beta (β), gamma (γ), delta (δ), epsilon (ε)

Q. The Sun is our closest star. What is the next closest star to us?
A. Alpha Centauri

Q. How old is our sun?
A. Our sun is estimated to be 4.5 billion years old, and is thought to be halfway through its life cycle.

Q. Do stars burn?
A. Burning is a reaction involving oxygen. Stars are balls of gas made of hydrogen and helium gases. They produce light and heat from nuclear fusion reactions.

Q. How hot are stars?
A. The surface temperature of stars varies depending on their colours. For example, a very hot star is a blue one with a surface temperature of 30 000 °C, a medium hot yellow star such as our sun is about 6000 °C, and a cool red star is about 2000 °C.