Did you know when you look at the night sky, youre actually looking back in time? By Cameron McEvoy, Griffith science student and Commonwealth Games gold medallist. Every time you look up at the stars, you’re actually looking back in time. This is all because of how far away the stars are and the finite speed of light. Out in space, light travels incredibly fast, at around 300,000 kilometres per second. But the nearest star to earth other than the sun—Proxima Centauri—is around four light years away. That means if you go outside tonight, the light you see from it has actually taken four years to get here... or to put it another way, you’re seeing something that happened four years ago. And that’s just the start. The Southern Cross might have started flashing bright neon pink 100 years ago, but we’re still looking at what was happening there 320 years ago. And if you really want to mess with your head, when you see the cloudy haze of the Milky Way, you’re looking at something that happened 2.7 million years ago.
Posted on: Fri, 17 Oct 2014 07:00:00 +0000
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