You’ve probably seen in books and magazines facts and figures they give for different things, like “Sirius is 8.7 light years away…” and “Each second the sun lets out enough energy to…”. If you’re anything like me you’ll wonder: how on Earth do they know that?

Always take claims with a pinch of salt- an astronomer’s viewpoint is limited to one point in time and space in the universe, hence, we can’t really be sure of anything. For instance I find it difficult to accept that we know exactly what happened 0.000000000001 seconds after the ‘big bang’, when we know only that the age of the universe is somewhere between 10 and 20 billion years old.

However, being so limited makes deducing information about the universe a challenge, and the ingenuity of some of the methods fascinates me.