Space myths BUSTED

From frozen astronauts to rampaging black holes, Alastair Gunn debunks 10 things you thought you knew about space

- Alastair Gunn

The Universe is a big and complex beast, and doesn't always behave in the way we might expect. So it's not surprising that there are many misconceptions and misunderstandings about space.

Some common myths - like the belief that there's a 'dark side' to the Moon, for example - arise because people generally don't have a reason (or time) to question them. Others arise because they're promoted on TV, in films and online. And some simply persist because, without detailed inspection, they seem perfectly plausible. But in the Universe, not everything is as it seems...

MYTH: The Sun is on fire

Our star certainly looks like a flaming inferno, but that’s not what's really going on...

The idea that the Sun is somehow burning has been around since ancient times. The Sun's heat and light were often attributed to molten metal or burning coal. But, armed with new knowledge of chemistry and thermodynamics, 19th-century scientists realised that no form of chemical energy was sufficient to fuel the Sun for more than a few thousand years. Instead of chemically combining with oxygen, like carbon does when coal is burnt, the Sun's fuel is undergoing thermonuclear reactions. Most of its energy is produced by the fusion of hydrogen into helium deep in the Sun's core, where temperature and pressure are huge.

Astronomers calculate the Sun is losing about 4.26 million tonnes of mass every second due to fusion (140 quadrillion tonnes per year). Since the Sun's mass is about 2 octillion tonnes, this is only 0.000000007 per cent of the Sun's total mass. So even at the end of its life, in about five billion years, the Sun will still have 99.966 per cent of its current mass.