Fact: The Sun’s fuel won’t last for ever

Fact: The Sun's fuel won't last for everThe Sun is fuelled by hydrogen, fusing 620 million tons of hydrogen nuclei into helium each second. This reaction produces solar radiation, which we experience as light and heat, but which also showers us with neutrinos – tiny particles that can pass through matter.

In fact, at this very second billions of neutrinos are passing through your body. The Sun is about 4.5 billion years old and, after comparing it to similar stars in our galaxy, astrophysicists reckon it is about halfway through its hydrogen burning stage. That leaves us another 5 billion years before its fuel begins to run low.

What exactly is dark matter?

By measuring the motion of stars in our galaxy and others, astronomers can tell that galaxies in general contain much more mass than can be accounted for by their visible stars, gas and dust. In fact, normal, or baryonic, matter (essentially anything with protons and neutrons) seems to account for just 15 per cent of all the mass in the universe