Cosmic inflation: Confidence lowered for Big Bang signal

The BICEP2 Collaboration used a telescope to detect a signal in the oldest light it is possible to observe at the South Pole.

Cosmic inflation: Confidence lowered for Big Bang signal

World Bulletin / News Desk

Scientists who claimed to have found a pattern in the sky left by the super-rapid expansion of space just fractions of a second after the Big Bang say they are now less confident of their result.

The BICEP2 Collaboration used a telescope to detect a signal in the oldest light it is possible to observe at the South Pole.

At the time the group's announcement in March, the discovery was hailed as a near-certain Nobel Prize, but they have recieved great criticism from the rivals who picked holes in the team's methods and analysis.

On Thursday, the BICEP2 collaboration formally published its research in a peer reviewed journal.

In the paper, the US-led group stands by its work but accepts some big questions remain outstanding.

One of BICEP2's principal investigators addressed that circumstances had changed addressing a public lecture in London.

"Has my confidence gone down? Yes," Prof Clem Pryke, from the University of Minnesota, told his audience.

The team announced at its 17 March press conference that it was the long sought evidence for "cosmic inflation". 

Developed in the 1980s, this is the idea that the Universe experienced an exponential growth spurt in its first trillionth of a trillionth of a trillionth of a second. 

It helps explain why deep space looks the same on all sides of the sky - the contention being that a very rapid expansion early on could have smoothed out any unevenness. 

Inflation theory makes a very specific prediction about the famous Cosmic Microwave Background being accompanied by waves of gravitational energy, and that these ripples in the fabric of space-time would leave an indelible mark on the oldest light in the sky. 

The BICEP team claimed to have detected this signal. It is called B-mode polarisation and takes the form of a characteristic swirl in the directional properties of the CMB light. 

It is, though, an extremely delicate pattern must not be confused with the same polarisation effects that can be generated by nearby dust in our galaxy. 

After scientists working on the European Space Agency's orbiting Planck telescope intensified significantly new information describing dust polarisation in the Milky Way critiques that have appeared since March have largely focused on this issue. 

Until new data emerges from other sources, the BICEP2 collaboration recognises that its inflation detection has greater uncertainty attached to it.

"[Our] models are not sufficiently constrained by external public data to exclude the possibility of dust emission bright enough to explain the entire excess signal," it writes in the PRL paper.

Last Mod: 20 Haziran 2014, 17:10
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