By Jonathan Amos
Science correspondent, BBC News
The measurements were taken using the BICEP2 instrument at the South Pole Telescope facility
Scientists say they have extraordinary new evidence to support a Big Bang Theory for the origin of the Universe.
Researchers believe they have found the signal left in the
sky by the super-rapid expansion of space that must have occurred just
fractions of a second after everything came into being.
It takes the form of a distinctive twist in the oldest light detectable with telescopes.
The work will be scrutinised carefully, but already there is talk of a Nobel.
"This is spectacular," commented Prof Marc Kamionkowski, from Johns Hopkins University.
"I've seen the research; the arguments are persuasive, and
the scientists involved are among the most careful and conservative
people I know," he told BBC News.
The breakthrough was announced by an American team working on a project known as
BICEP2.
This has been using a telescope at the South Pole to make detailed observations of a small patch of sky.
The aim has been to try to find a residual marker for
"inflation" - the idea that the cosmos experienced an exponential growth
spurt in its first trillionth, of a trillionth of a trillionth of a
second.
Gravitational waves from inflation put a distinctive twist pattern in the polarisation of the CMB
Theory holds that this would have taken the infant Universe
from something unimaginably small to something about the size of a
marble. Space has continued to expand for the nearly 14 billion years
since.
Inflation was first proposed in the early 1980s to explain
some aspects of Big Bang Theory that appeared to not quite add up, such
as why deep space looks broadly the same on all sides of the sky. The
contention was that a very rapid expansion early on could have smoothed
out any unevenness.
But inflation came with a very specific prediction - that it
would be associated with waves of gravitational energy, and that these
ripples in the fabric of space would leave an indelible mark on the
oldest light in the sky -
the famous Cosmic Microwave Background.
The BICEP2 team says it has now identified that signal.
Scientists call it B-mode polarisation. It is a characteristic twist in
the directional properties of the CMB. Only the gravitational waves
moving through the Universe in its inflationary phase could have
produced such a marker. It is a true "smoking gun".
"Detecting this signal is one of the most important goals in
cosmology today. A lot of work by a lot of people has led up to this
point," said Prof John Kovac of the Harvard-Smithsonian Center for
Astrophysics and a leader of the BICEP2 collaboration.
The signal is reported to be quite a bit stronger than many
scientists had dared hope. This simplifies matters, say experts. It
means the more exotic models for how inflation worked are no longer
tenable.
The results also constrain the energies involved - at 10,000
trillion gigaelectronvolts. This is consistent with ideas for what is
termed Grand Unified Theory, the realm where particle physicists believe
three of the four fundamental forces in nature can be tied together.
But by associating gravitational waves with an epoch when
quantum effects were so dominant, scientists are improving their
prospects of one day pulling the fourth force - gravity itself - into a
Theory of Everything.
The sensational nature of the discovery means the BICEP2 data will be subjected to intense peer review.
It is possible for the interaction of CMB light with dust in
our galaxy to produce a similar effect, but the BICEP2 group says it has
carefully checked its data over the past three years to rule out such a
possibility.
Other experiments will now race to try to replicate the
findings. If they can, a Nobel Prize seems assured for this field of
research.
Who this would go to is difficult to say, but leading figures
on the BICEP2 project and the people who first formulated inflationary
theory would be in the running.
"I can't tell you how exciting this is," said Dr Jo Dunkley, who has been searching through data from the
European Planck space telescope for a B-mode signal.
"Inflation sounds like a crazy idea, but everything that is
important, everything we see today - the galaxies, the stars, the
planets - was imprinted at that moment, in less than a trillionth of a
second. If this is confirmed, it's huge."
"Everything we see today - the galaxies, the stars, the planets - was imprinted at that moment"
