Australasian Science Magazine

By AusSMC

Astronomers have found evidence that the Universe underwent a period of rapid inflation in the very first moments of its existence. If confirmed, the tell-tale signature of gravitational waves in the afterglow of the Big Bang will open a new chapter in astronomy, cosmology and physics.

Astronomers using a radio telescope based at the South Pole have peered into the afterglow of the Big Bang and seen the tell-tale whirls of light (called B-modes) that are caused by ripples in space–time (indirect evidence for Einstein's final prediction, which is a big deal). These ripples (or gravitational waves) would normally be too small for us to detect, yet something has blown them up to the size of the entire Universe. That something is inflation, and this discovery is the first confirmation of this incredible, potential Nobel Prize-winning result.

The size and strength of the gravitational waves tells us that a trillionth of a trillionth of a trillionth of a second (10-36 or so) after the Big Bang, the Universe was smaller than an atom and suddenly ballooned in size. We don't know how inflation caused this accelerated expansion (or even why it stopped), but it caused the Universe to increase in size 100 trillion trillion trillion trillion times larger, at least – a near-unbelievable amount were the effects of it not staring us in the face as we look at the gravitational waves that should be smaller than an atom now stretched across the sky.

Inflation brings together the two major theories on which our economies depend – general relativity, which ensures GPS positions stay accurate, and quantum mechanics, which governs how computers run. Combining the two theories is fraught with difficulty yet inflation offers scientists a chance to test out theories of the future with as-yet undreamed of spin-off technologies.

Dr Alan Duffy is a Postdoctoral Research Fellow in the University of Melbourne’s School of Physics.

----------

The word is that the BICEP team has discovered B-modes: specific patterns in the polarisation of the microwave background. B-modes are the “smoking gun” of inflation, and their strength is tied to the energy density of the Universe during inflation. If the rumours hold up, we could soon know that inflation did happen a trillion, trillion, trillionth of a second after the Big Bang, and at energies a trillion times beyond the reach of the Large Hadron Collider.

There would still be several steps to nailing it down. Not all B-mode signals must come from inflation, and not all inflationary models must produce detectable B-modes. And there's one more thing: the B-mode is sourced by gravitational waves – ripples in the fabric of space – generated during inflation.

Gravitational waves are a key prediction of Einstein's General Relativity, and their existence is still not conclusively confirmed. Even so, gravitational waves are getting second billing to what we will learn about the early Universe: we will know that inflation is a compelling answer to cosmology's initial-conditions problems, and humankind will have looked directly into the cosmic dawn.

Professor Richard Easther is Head of the Department of Physics at the University of Auckland.

-----------

Modern cosmology is based on three underlying assumptions – inflation, dark matter and dark energy. We don’t know what any of them actually are, but over the last few years we have seen increasingly strong evidence that they are real.

Today’s announcement from the Bicep project continues that process. Inflation is the very rapid expansion of the very early Universe that is one of the pillars of our understanding of cosmology. Without inflation we would not be here.

A detection of primordial B-mode polarisation provides very strong evidence for inflation and, if the Bicep results are verified by other experiments, that will be what we have. With the recent confirmation of the existence of the Higgs boson and now the first direct evidence for inflation, these are very exciting times to be a physicist.

Professor John Womersley is Chief Executive of the Science and Technology Facilities Council, which funds UK research into cosmology.