Space messengers deliver clues to the universe
Scientists on the hunt for exploding stars and black holes at the heart of galaxies are not looking up to the skies to find them but down into the depths of the Earth.
Using the world's biggest telescope constructed two and a half kilometres beneath the south pole in Antarctica, they are searching for neutrinos. The high energy particles act as messengers from space to provide clues as to how the universe works.
"It's a new window on the universe, a new way of looking at the universe," said astro-particle physicist Jenni Adams from Canterbury University in New Zealand.
In Melbourne to attend the International Conference on High Energy Physics, Professor Adams said mystery surrounded the force behind the creation of particles such as protons and neutrinos.
Known as IceCube, the telescope is a giant particle detector that scientists hope will solve the mystery by recording the interactions of neutrinos as they pass through the ice at the south pole at close to the speed of light.
Professor Adams said the neutrinos detected to date came from our own atmosphere but scientists hoped to find neutrinos from out of space, which may have formed from colliding black holes or massive supanova explosions, which take place at the end of a star's lifetime.
The path the neutrinos take to get to Earth is what scientists are most interested in, as this will lead them to the force which created the sub-atomic particles.
A neutrino is a neutral particle which has a very small mass, allowing it to not only pass through the Earth but through people as well.
"You hold up your finger and a hundred billion neutrinos pass through it every second from the sun," Professor Adams said.
While neutrinos are neutral, protons, which also come from out of space, are positively charged. This charge means the magnetic field bends the path of the proton effectively robbing scientists of the chance to trace the path they travelled back to the source which created them.
"We know that protons are produced out there but we can't tell where they came from," Professor Adams said.
This is why neutrinos are so intriguing. Their low mass and uninterrupted path makes them ideal candidates for tracking back to the source. And where neutrinos are produced, so are protons.
"We know that there are big accelerators out in space that are a hundred-billion times more powerful than the Large Hadron Collider we built in Europe. We know they are there because of the protons but they can't tell us where."
The ice telescope is made up of 80 holes created by melting the ice to an average depth of 2.4 kilometres. A cable with basketball-sized light detectors attached every 17 metres is suspended the length of the tunnel.
The IceCube, a $280 million international project largely funded by America, has been collecting data since 2008. Around 200 scientists from across the globe work on it at any one time.
A smaller particle detector also operates from the Mediterranean Sea off the coast of France.