Plancking at U of T: space mission sheds light on universe's age and evolution

The best map ever made of the most ancient light in the universe — the remnant radiation left over from the Big Bang some 13 billion years ago — deepens our understanding of the universe.

The highly detailed image of the universe — produced by the European Space Agency’s Planck Space Telescope and the Planck collaboration of international scientists including a team from the University of Toronto — reveals that the universe is slightly older, expanding more slowly and has more matter than previously thought.

“For all of us, the magic is how we translate the observations of the spatial patterns in this ‘first light’ of the universe to the structure that must have been there in the earliest moments when our observable universe — currently some giga-giga-giga-metres across — was compressed to smaller than a nano-nano-nano metre across,” said U of T University Professor Richard Bond.

Bond and Douglas Scott of the University of British Columbia co-lead a Canadian science team that played a key role in the Planck collaboration. Bond is on the faculty at the Canadian Institute for Theoretical Astrophysics (CITA) and directs the Cosmology and Gravity program of the Canadian Institute for Advanced Research (CIFAR).

The team included astrophysicists at the University of Toronto, University of Alberta, Université Laval and McGill University.

Planck's evidence confirms and refines previous models of how astronomers believe the universe originated and evolved, but with intriguing new details:
• The Planck team has calculated that the universe is 13.82 billion years old — 80 million years older than earlier estimates
• The Planck Space Telescope has revealed that the universe is expanding slower than the current standard determined with the Hubble Space Telescope
• Planck has also allowed cosmologists to confirm the universe's composition more accurately than ever before: normal matter, the stuff of stars and galaxies like our own Milky Way, makes up just 4.9 per cent of the universe.

Dark matter — the presence of which so far has been inferred only through the effects its gravity causes — accounts for 26.8 per cent. Dark energy — a mysterious force that behaves the opposite way to gravity, pushing and expanding our universe — makes up 68.3 per cent of the universe — slightly less than previously thought.

Planck's precision has also given astrophysicists a number of new puzzles to solve.

"For more than three decades, I have been trying to unveil the structure imprinted on the universe from an epoch of accelerated expansion in its earliest moments," said Bond. "Planck has now shown that the evidence for this early inflation is much stronger than before.

"The patterns we see are quite simple, resulting in many formerly viable theories falling victim to our Planckian knife. Our maps reveal unexplained, large-scale features that excite the imaginations of physicists who have been eagerly awaiting what Planck has to say about the early universe."

Launched in 2009, the Planck telescope has been scanning the skies ever since, shedding light on the beginnings of the universe and the birth of stars. The telescope's incredible accuracy allows it to pinpoint faint, minute patterns — differences in light and temperature that correspond to slightly different densities in the matter left over from the Big Bang.

The data released March 21 at ESA headquarters in Paris, France is from the first 15 months of the mission. It shows a map of the universe when it was just 380,000 years old.

"We now have a precise recipe for our universe: how much dark and normal matter it is made of; how fast it is expanding; how lumpy it is and how that lumpiness varies with scale; and how the remnant radiation from the Big Bang is scattered," said Scott. "It is astonishing that the entire universe seems to be describable by a model using just these six quantities. Now, Planck has told us the values of those numbers with even higher accuracy."

Twenty-eight scientific papers from the Planck mission were published on-line, covering many aspects of how the universe is put together and how it has evolved. Planck's instruments allow astronomers to separate the primordial light from the effects of dust and other emissions coming from our Milky Way Galaxy.

"We do not simply sweep away the dust signal into the trash bin, but rather treasure it for what it tells us about the workings of the Galaxy," said U of T and CITA astrophysicist Peter Martin, who is working on a series of papers that will be published in another upcoming release on this data.

"It enables us to discover the evolution of structure in the interstellar medium leading from a diffuse state to star formation in dense molecular clouds."

Hundreds of astronomers from around the world will continue to study Planck's data as the telescope continues its observations.

The complete results of the mission are scheduled to be released in 2014.

In addition to Bond and Martin, the current U of T scientists in the Planck mission include CITA’s Mike Nolta and Marc Antoine Miville Deschenes (based in Paris), and Barth Netterfield of the Department of Astronomy and Astrophysics, who led the large software effort at U of T used to check the data as it poured in from the satellite.

The Canadian Space Agency funds two Canadian research teams who are part of the Planck science collaboration, and who helped develop both of Planck's complementary science instruments, the High Frequency Instrument and the Low Frequency Instrument.

With files from the Canadian Space Agency