Wonders of the Universe

FROM BIG BANG TO SUNSHINE: THE FIRST STARS

The first stars formed around 100 million years after the Big Bang. The rate at which they burned their hydrogen fuel essentially depends on their mass. The more massive the star, the brighter it shines and the shorter its lifetime. The key to understanding how the heavier elements came into being lies in what happens to stars when they have exhausted their hydrogen fuel. For the most massive known stars, this may take only a few million years. For stars like our sun, it may take ten billion years – but the Universe has been around for plenty of time to allow generations of stars to live and die.

The brightly shining constellation of Orion is clearly visible as it sets in the night sky.

© Tony Hallas/Science Faction/Corbis