Science //

Listening to the stars

Felicity Nelson gets attuned to the Universe.

It’s strange to think that the silent night sky actually holds a symphony of sounds. If you listen carefully enough,  stars tens of millions of light years away will whisper the secrets of the universe into your ear. Unfortunately, you need a very special kind of ear called a radio telescope to distinguish these very quiet voices from the cacophony of vibrations here on Earth.

A radio telescope is exactly like an eye. Except it’s huge; the largest one in the world is 350m across. It has a dish that acts like a lens by focusing the incoming waves onto a central detector above and in the centre of the dish (like the retina), which in turn transmits the data to a radio receiver (optic nerve). Scientists at the other end (the brain in this analogy) get a tangle of different signals that they then have to tease out to identify different sources of vibrations.

Scientists can only really understand what’s going on in the universe by listening to it in this way.  All the wackiest inhabitants of our universe including black holes, quasars, pulsars and supernovas have been discovered and described using radio telescopes. These entities are so far away that the radio waves they emit take literally billions of years to reach Earth. What our telescopes are really detecting is the beginning of time, a universe in its infancy. Humanity’s knowledge about the origins and fate of our universe rests on theses large ears trained at the sky.

Aliens, if they are out there, will be heard by our telescopes. SETI has been on the watch for little green men for over thirty years. UC Berkley’s SETI@home project has been outsourcing telescope data to volunteer’s computers for over ten years. It is still possible to join this search by downloading a screensaver from their website which processes pieces of data from their telescopes when you aren’t using your computer.

A new multi-nationally funded project to spread a large number of connected telescopes over a 3km area in either Western Australia or South America is on its way. This square kilometre array to be completed in 2024 will be fifty times as sensitive as current technologies. It is estimated that the computing power of 100 billion PCs will be needed to process all the data collected. Even the weakest television transmissions from a solar system millions of light years away will be picked up. By focusing on the dust rings around newly-formed suns 15 billion light years away this new technology is expected to answer many questions about the nature of the universe.

The universe is beautiful, wonderful and articulate. I can not think of anything more inspiring than humanity’s ability to look up at the sky and know much more of what’s there than, quite possibly, anything else in the universe.

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