The Expanding Universe of Astronomy
By John R. Percy
Professor Emeritus: Astronomy & Astrophysics, and Science Education
University of Toronto

What an interesting project — to encourage our members to reflect on the evolution of their discipline!  I’m not a professional historian – far from it – but I’m actively interested in heritage.  I lead astronomical walking tours of our campus for Heritage Toronto, and give public presentations based on the walk.  I prepared the “Astronomy at U of T” page in the Senior College Encyclopaedia.  Toronto has a proud astronomical heritage, going back to — and beyond — the iconic 1855 Toronto Magnetic and Meteorological Observatory – now called the Stewart Observatory, and home to the U of T Student Union.

In the 60 years since I was an undergraduate astronomy student at U of T, humans have flown in space and landed on the moon.  Space probes have explored all the planets in the solar system (including the ex-planet Pluto) and many of their moons.  Thousands of “exoplanets” have been discovered around other stars, including dozens of Earth-like ones.  Astronomers now understand the life cycles of the sun and stars, including their bizarre end-products: white dwarfs, neutron stars, and black holes.  They have shed new light on the origin and evolution of galaxies and the universe itself, and even recorded the after-glow of the universe’s birth – the so-called Big Bang.  Science speculation and fiction has become science fact – in living colour.

These advances have come about through new instruments and techniques: giant telescopes on mountaintops in Chile and Hawai’i, telescopes in space, super-sensitive electronic detectors, observations across the electromagnetic spectrum from gamma rays to radio waves, and powerful computers and software to remotely operate our telescopes, analyze the “big data” from them, and model the structure and evolution of stars, galaxies, and the universe.  Canada is part of many of these projects.  The costs can be high, which requires either international collaboration (e.g. the European Southern Observatory in Chile) or a rich patron (e.g. the Keck Observatory in Hawai’i).  This research also requires an increasingly interdisciplinary approach: physics, engineering, mathematics, statistics, computer science, Earth and planetary science.

As is usually the case, such advances have led to new and deeper questions.  What is the “dark matter” that makes up most of the mass of the universe?  What is the “dark energy” which causes the expansion of the universe to accelerate?  How do supermassive black holes form at the centres of galaxies, including ours?  What is the ultimate nature of matter, anyway?  (Observations of the Big Bang can help.)  Is there any form of life on the dozens of newly-discovered Earth-like planets?   And more philosophical questions: what came before the Big Bang?  So awe and wonder continue.

The number of professional astronomers and graduate students in Canada has quadrupled since the formation of the professional Canadian Astronomical Society in 1971.  This is in part because of the steady growth of university enrolments, and exciting research opportunities, but also because of the popularity of astronomy courses – especially introductory courses for non-science students.  At U of T, there are two such courses with enrolments of 1,500 (and waiting lists).  They are taught in Con Hall by award-winning instructors, using best-practice pedagogy and technology, small-group tutorials, and a small planetarium.

There are also students in astronomy major and specialist programs, and 57 graduate students from all over the world.  Most go on to academic careers, but a significant number of these “highly qualified personnel” (to use the current terminology) now apply their skill set outside academia, to high-tech fields such as data science and artificial intelligence, as well as to public education, outreach, and communication.

To accommodate this growth, we are well-advanced in planning for a new building, to be built on the site of the present 50 St. George Street.  Among other things, it will include a planetarium, for students, and the public.  We still lament the unnecessary closing of the ROM’s McLaughlin Planetarium.

Astronomy research in Canada is carried out in the federal Herzberg Institute of Astrophysics, based in Victoria, as well as in university departments and institutes across the country.  U of T has hosted the Canadian Institute for Theoretical Astrophysics – a jewel in Canada’s science crown — since 1984.  There is a Centre for Planetary Science on the Scarborough campus.  In 2008, the University and the David Dunlap family established the Dunlap Institute for Astronomy and Astrophysics, funded by the sale of lands around the Dunlap Observatory in Richmond Hill.  The observatory is now owned by the municipality, and run as a public-education facility by volunteers.  The Dunlap Institute’s mandate is four-fold: building state-of-the-art astronomical instruments; making innovative observations; training the next generation of astronomers; and informing and inspiring the public about astronomy in general and the U of T’s work in particular.

Training includes a strong summer undergraduate research program, short courses and workshops in the summer and throughout the year, as well as through our undergraduate and graduate programs.  Defining our values, and improving our professional culture — equity, diversity, inclusivity, and sustainability — is an increasing priority for us and for astronomers across Canada.  Half a century ago, for instance, most astronomers were male — one exception being my eminent colleague Helen Sawyer Hogg.  Now, most of my bright young colleagues are women.

There is new attention being given to Indigenous rights and indigenous knowledge.  Mauna Kea is home to a dozen major observatories, some shared by Canada.  It is also sacred land for indigenous people of Hawai’i, and this has sparked local demands for “no more observatories on the sacred peak” – at least not without respectful consultation and agreement.

At the same time, universities encourage all academic units to incorporate indigenous ways of thinking and knowing in their courses, where appropriate.  At U of T, this has led to a course on Indigenous Astronomy, given by an Indigenous faculty member.

Astronomy is engaging to many members of the general public, and their interests range from the technological to the philosophical and spiritual.  Astronomers respond through communication and outreach.  We are greatly aided by enthusiastic amateur astronomers.  In 2003, the mostly-amateur Royal Astronomical Society of Canada, founded in 1868, won the prestigious Michael Smith Award for excellence in science outreach in Canada.  In 2009, professional and amateur astronomers and educators in 148 countries marked International Year of Astronomy, a celebration of the 400th anniversary of Galileo`s development and first use of the astronomical telescope.  We organized over 3700 events in Canada, reaching almost two million people.  There were also wildly-popular commemorative stamps, and engaging posters on buses and subway trains, and creative partnerships with new audiences — including, for me, Toronto’s Tafelmusik Baroque Orchestra, and Heritage Toronto.

The RASC archivist (a mediaevalist by training) is a national leader in preserving Canada`s astronomical heritage – both professional and amateur.  This is a serious matter; as older observatories (such as the Dunlap Observatory) are “retired”, how can they and their history be preserved?  How can their science be preserved for posterity when much of it is on photographic plates, or on magnetic tapes?

Skilled amateurs contribute in other ways.  My own research on variable stars and stellar evolution depends critically on decades of amateurs’ visual and electronic measurements of the changing brightness of stars.  Indeed, “citizen science” is a growing trend in science and society.  A current example is the HowsMyFlattening project, which is giving us more and better CoVid-19  data than governments have been able to do.  Sadly, most amateur astronomers in North America are graying white males (like me); we need to increase diversity.

Despite scientists’ efforts, science literacy remains low.  Studies indicate that over one-third of Americans believe in astrology, space aliens, and young-Earth creationism.  Canadians do a bit better – but not much.  Very few people understand the cause of the seasonal changes in temperature (hint: it has nothing to do with the distance from Earth from the sun).  There is a gap between scientists’ knowledge and public knowledge, which we must try harder to close.

Why fund astronomy in these difficult times?   It may have no immediate practical value, but it has long-term applications and spin-offs.  Public interest is high, especially among young people.   This is important: for them, astronomy is now part of the school science curriculum, and it can be a gateway to STEM interests and careers.  Astronomy is as old as humanity; it’s part of our shared heritage.  The sky has provided a clock, calendar, and compass, and has been deeply ingrained in spirituality for cultures across the globe, and across time.  Now, it deals with some of humanity’ most fundamental questions.