Stars are hot balls of gases which burn for millions of years.
They are formed in "stellar nurseries" when gases and
dust particles are pulled together by gravity. The heat generated
by stars is what makes them shine. Their temperatures reach hundreds
of thousands degrees Celsius.
Stars have different characteristics. The colour, or spectral type,
of a star ranging from blue to white to yellow to red - can
give us an indication of its age. Our nearest star, The Sun, is
yellow, has shone for some 5,000 million years, and is roughly half-way
through its life cycle. The Sun is 93 million miles away.
The next nearest star to us is in the Centaurus constellation and
is 4.5 million million miles away. To put it in perspective, if
you imagine the earths relative distance from the Sun as the
length of 3 feet - the next closest star is literally as far the
Moon about 239,000 miles away. Distances in space are so
great that astronomers use light years as a measure rather than
ordinary miles or kilometers. One light year is the distance light
travels in a year, which is about 6 million million miles.