At a Glance

Founded1986
Renewal dates1991, 1996, 2001, 2007, 2012
Members46
SupportersR. Howard Webster Foundation
Disciplines
Astrophysics; astronomy; astroparticle, computational, high energy and particle physics; observational cosmology

What is the nature of the universe?

Cosmology is at the root of some of the biggest questions in science. How did the universe begin? How did it evolve to its present form? What are the natures of dark matter and dark energy? Can we reconcile the seemingly contradictory worlds of quantum mechanics and general relativity?

Looking for answers to these fundamental mysteries helps us understand where we’ve come from and where we might be going, and allows us to study physics on scales too big for Earth-based laboratories.

Our unique approach

CIFAR’s Cosmology & Gravity program brings together some of the world’s most highly-regarded astronomers and cosmologists. The international team includes 45 leading experts in fields such as compact object physics, numerical relativity, string theory and particle astrophysics. The program is deliberately broad in scope. It was founded on the belief that only by bringing together physical cosmologists, particle physicists, gravitational theorists, forefront observers and instrumentalists could progress be made in answering the deepest questions about the origin and evolution of the universe. This unique, multidisciplinary mix of theory and observation creates a fertile environment for new ideas.

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A visualisation of the polarisation of the Cosmic Microwave Background as detected by ESA’s Planck satellite on a small patch of the sky measuring 20º across. Image courtesy of the European Space Agency

Why this matters

In the 20th century, physics was dominated by two seemingly contradictory theories: quantum mechanics, which applies mainly to sub-atomic particles, and general relativity, which describes systems on a cosmic scale. Neither theory works well at the other’s scale, and so far all attempts to unify the two have failed. The quest for a “theory of everything” is one of the most important unsolved problems in physics. CIFAR’s Cosmology & Gravity program began as an attempt to solve that problem. Since then it has expanded to tackle other unanswered questions about how galaxies form, the nature of dark energy and dark matter, the properties of fundamental particles, and the behaviour of matter in the most extreme environments in the Universe. A better understanding of the nature of the universe can help us grapple with the question of our own existence: is it the result of an extremely unlikely coincidence, or are the physical laws that allow our existence inevitable?

In depth

CIFAR’s unique team is able to take the models and hypotheses put forward by theorists and put them to the test using observations from advanced telescopes, including ground-based, balloon-borne and satellite observatories. Their work includes: Theories of the early universe A major focus of the Cosmology & Gravity program is on tracing the evolution of the early universe, from the Big Bang through its first several hundred thousand years. Some of the light from this period is still around today. Known as cosmic microwave background (CMB), it is found at outer reaches of the observable universe. Team members are using tools like the Planck space telescope or the BICEP2 collaboration at the South Pole to test the current thinking about this time period. For example, a team that included Program Director J. Richard Bond, Senior Fellow Barth Netterfield, Associate Fellow George Efstathiou and Advisor Simon White recently published a set of papers which, among other things, showed that the first stars formed 140 million years earlier than was previously believed. They also showed that observations previously thought to be evidence of gravitational waves from a rapidly-expanding early universe were more likely caused by cosmic dust distorting the light. The program also includes prominent theorists such as Senior Fellow Neil Turok. His novel cyclic model for cosmology, according to which the Big Bang is explained as a collision between two “brane-worlds”, is an alternative theory of early universe formation that could be tested by new observations. Cosmic signposts Another major area of research involves looking for cosmic signposts that can help researchers more accurately measure the size and shape of the universe, as well as the rate at which it is expanding. Researchers in this area include R. Howard Webster Foundation Fellow Victoria M. Kaspi, Senior Fellow Ray Carlberg, Senior Fellow Ingrid Stairs, Associate Fellow Wendy Freedman and many others. The signposts in question can be stars that vary their brightness at predictable intervals, such as pulsars. Comparing the brightness of these pulsing stars allows researchers to determine how quickly they are moving apart. Stellar explosions like supernovae are the furnaces in which elements heavier than iron are born. A comprehensive survey of supernovae, carried out with the Canada-France-Hawaii telescope, offered new insights into the expanding universe and the distribution of matter within it. Particle astrophysics Canada is home to a unique piece of research equipment: an underground science laboratory called SNOLAB, located two kilometers below the surface in the Vale Creighton Mine near Sudbury, Ontario, Canada. The underground location shields the equipment from the cosmic radiation ubiquitous on the surface of the Earth, and allows it to more easily detect particles such as neutrinos. CIFAR members like Senior Fellow Mark Chen are collaborating with SNOLAB to learn more about neutrinos. These ghostly particles could offer clues about larger mysteries, including the nature of dark matter, the lack of antimatter  in today’s universe, and the validity of alternatives to the Standard Model  of particle physics. Extreme environments Neutron stars and black holes contain matter at incredibly high density, which in turn leads to enormous magnetic fields and powerful gravity. Theorists like Distinguished Fellow Werner Israel and Senior Fellow Matthew Choptuik build mathematical models that can tell us what happens to matter under these extreme conditions. These in turn shed light on the nature of gravity. Next-generation instruments CIFAR collaborations have been critical in bringing about some of the most significant “big science” projects in recent years. For example, Canada recently committed $243.5 million to construct the Thirty Meter Telescope, to be built on Hawaii’s Mauna Kea. Its mirror would be more than twice as wide as the largest telescopes operating today, offering an unprecedented ability to peer into the faintest corners of the universe. The seeds of Canada’s involvement in the project were sown in a CIFAR Cosmology & Gravity meeting more than ten years ago. CIFAR fellows are driving development of a revolutionary new radio telescope called the Canadian Hydrogen Intensity Mapping Experiment (CHIME). It will observe radio waves at the 21 cm spectrum, building three-dimensional maps of the Universe and probing the mysteries of dark matter, as well as collecting observations of pulsars and newly discovered and mysterious objects known as fast-radio bursts. The telescope, under construction near Penticton, BC, consists of three stationary steel half-cylinders, each about 100 metres long and about 20 metres wide. As the Earth rotates the telescope sweeps the sky, collecting and analyzing radio waves with the help of specially designed electronics.

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Fellows in the program are deeply involved in building the revolutionary CHIME radio telescope in Penticton, BC, which will build three-dimensional maps of the universe

Antimatter has been created and manipulated in lab conditions. It consists of antiparticles, which have the same mass as their equivalents in ordinary matter, but the opposite charge, as well as other contrary quantum properties like spin. When a particle meets its antiparticle, it annihilates, sometimes forming neutrinos. According to leading theories, roughly equal amounts of matter and antimatter should have been created during the Big Bang. Yet today the universe is almost entirely made of matter, a major unsolved puzzle in physics. The Standard Model is the traditional ‘recipe book’ for how to build our universe. It is a theory of particle physics that contains four fundamental forces —gravity, electromagnetism, strong nuclear force, weak nuclear force — and 17 subatomic particles, including quarks, electrons, photons, the Higgs boson and many others. It has been very successful at explaining most observable physical phenomena. However, it can only partially explain gravitation as explained by general relativity, and does not account for other phenomena, such as the accelerating expansion of the universe (hence the requirement for Dark Energy). A number of extensions which aim to bring the Standard Model more closely in line with observations have been proposed, including supersymmetry and string theory. Determining which of these would be the best improvement on the Standard Model is the goal of many theoretical and experimental physicists.

Selected papers

L. Kofman, A. Linde and A. Starobinsky, “Reheating after Inflation”, Physical Review Letters 73, 24 (Dec. 1994): 3195 V. Frolov and I. Novikov, Black Hole Physics, Springer Fundamental Theories of Physics series (1998). Q.R. Ahmad et al, “Measurement of charged current interactions produced by 8B solar neutrinos at the Sudbury Neutrino Observatory,” Physical Review Letters 87, 7 (2001): 13 doi: http://dx.doi.org/10.1103/PhysRevLett.87.071301 The Planck Collaboration, “Planck 2013 results. I. Overview of products and scientific results,” Astronomy & Astrophysics 571 (2014).

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Fellows & Advisors

Photo of J. Richard Bond

J. Richard Bond

Program Director

J. Richard Bond's theoretical work ranges from the ultra early to the ultra late universe, with influential works on the nature and behaviour of dark matter and energy, on inflation…

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Fellows

Lars Bildsten

Associate Fellow

University of California, Santa Barbara

United States

Raymond G. Carlberg

Senior Fellow

University of Toronto

Canada

Mark C. Chen

Senior Fellow

Queen's University

Canada

Matthew W. Choptuik

Senior Fellow

University of British Columbia

Canada

Andrew Cumming

Associate Fellow

McGill University

Canada

Matt Dobbs

Senior Fellow

McGill University

Canada

George P. Efstathiou

Associate Fellow

University of Cambridge

United Kingdom

Wendy Freedman

Associate Fellow

University of Chicago

United States

Carlos S. Frenk

Associate Fellow

Durham University

United Kingdom

Daniel Green

Associate Fellow

University of California, Berkeley

United States

Mark Halpern

Senior Fellow

University of British Columbia

Canada

Gary Hinshaw

Senior Fellow

University of British Columbia

Canada

Henk Hoekstra

Associate Fellow

Leiden University

Netherlands

Gilbert Holder

Senior Fellow

University of Illinois at Urbana-Champaign

United States

Werner Israel

Distinguished Fellow

University of Victoria

Canada

Shamit Kachru

Associate Fellow

Stanford University

United States

Nicholas Kaiser

Associate Fellow

University of Hawaii

United States

Renata Kallosh

Associate Fellow

Stanford University

United States

Victoria M. Kaspi

R. Howard Webster Foundation Fellow

McGill University

Canada

Luis Lehner

Senior Fellow

Perimeter Institute for Theoretical Physics

Canada

Andrei Linde

Associate Fellow

Stanford University

United States

Arthur B. McDonald

Associate Fellow

Queen's University

Canada

Robert C. Myers

Senior Fellow

Perimeter Institute for Theoretical Physics

Canada

Julio F. Navarro

Senior Fellow

University of Victoria

Canada

Barth Netterfield

Senior Fellow

University of Toronto

Canada

John A. Peacock

Associate Fellow

The University of Edinburgh

United Kingdom

Ue-Li Pen

Senior Fellow

University of Toronto

Canada

Harald P. Pfeiffer

Fellow

University of Toronto

Canada

E. Sterl Phinney

Associate Fellow

California Institute of Technology

United States

Frans Pretorius

Associate Fellow

Princeton University

United States

Scott Ransom

Associate Fellow

National Radio Astronomy Observatory

United States

Joseph Silk

Associate Fellow

University of Oxford

United Kingdom

David Spergel

Associate Fellow

Princeton University

United States

Ingrid Stairs

Senior Fellow

University of British Columbia

Canada

Alexander S. Szalay

Associate Fellow

The Johns Hopkins University

United States

Neil Turok

Senior Fellow

Perimeter Institute for Theoretical Physics

Canada

William G. Unruh

Senior Fellow

University of British Columbia

Canada

Ludovic Van Waerbeke

Senior Fellow

University of British Columbia

Canada

Matias Zaldarriaga

Associate Fellow

Institute for Advanced Study

United States

Advisors

Roger Blandford

Advisor

Stanford University

United States

Richard S. Ellis

Advisor

University College London, European Southern Observatory

Germany

Lyman Page

Advisor

Princeton University

United States

Eva Silverstein

Advisor

Stanford University

United States

Scott D. Tremaine

Advisory Committee Chair

Institute for Advanced Study

United States

Simon White

Advisor

Max Planck Institute for Astrophysics

Germany

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