Ask a Scientist

Ask a Scientist - Shanil Virani

Day Becomes Late Twilight for a Narrow Span of Ontario, Quebec, New Brunswick, and Newfoundland!

During mid-afternoon on April 8, 2024, the Moon’s orbit will take it in front of the Sun. If the sky is clear, observers in parts of Ontario, Quebec, New Brunswick, and Newfoundland will be treated to a spectacular celestial event that mystified our ancestors for millennia – a total solar eclipse! During this time, the Moon blocks the Sun and day will darken to late twilight for a period of up to several minutes. Nocturnal animals will wake from their sleep thinking night has arrived. The temperature can drop by about 5 degrees Celsius! Birds will fall silent and bees will return to their hive. A few minutes later, the Sun will reappear and the day will continue as if nothing happened at all. There is nothing like the wonder and awe of a total solar eclipse!

Observing a total solar eclipse at a particular location on the planet is very rare. The last time the citizens of Southern Ontario observed a total eclipse was in 1925. The next one won’t happen until October 2144! April 8, 2024 represents a once-in-a-lifetime opportunity to catch one of the rarest of astronomical phenomena from Southern Ontario. Unfortunately, the narrow band of totality – that region of where observers will see a total eclipse of the Sun – will miss the populous cities of London, Toronto, and Ottawa. Folks in those areas will need to travel to the south or to the east to observe a total eclipse. However, even if they don’t, they will see a substantial partial eclipse where the Moon will appear to have taken a big bite out of the Sun! But they will miss seeing the outer atmosphere of the Sun bursting forth to visibility when the Moon fully blocks the light from the disc of the Sun.

Residents of Southern Ontario will not have to travel far to get to an area that lies within the path of totality. Locations east of Hamilton, specifically along the Niagara Peninsula, and the entire western lake shore of Lake Erie lie within the narrow band. Folks near Kingston, Thousand Islands National Park and the northern lake shore of Lake Ontario also lie within the band of totality. Cities in western New York – Buffalo, Rochester, and Syracuse – offer some of the best spots to observe the total eclipse as totality will last nearly 4 minutes (compared to slightly less than 2 minutes in Hamilton)! Many of these U.S. communities have planned for this event for years and are expecting upwards of 100,000 observers to witness the event at eclipse festivals. So plan for plenty of travel time and potentially large traffic jams on the day of the eclipse as people head to the Niagara Peninsula area.

Other than clear skies – or at least clear skies in the direction of the Sun – the only thing necessary to observe an eclipse are a pair of approved eclipse glasses or a pinhole camera (there are lots of plans online, for example, https://www.asc-csa.gc.ca/eng/youth-educators/activities/fun-experiments/eclipse-projector.asp). Our Sun is a powerful star: looking directly at it, even very briefly, will permanently damage your eyesight. The only time it is safe to take off your eclipse glasses is during totality; if your city is not within the band of totality, you should never remove your eclipse glasses during the event.

For those fortunate to observe the total solar eclipse, many people may try to futz with their camera or cell phone to capture the moment. Trust me, within minutes the internet will be flooded with pictures! Instead I would encourage participants to simply be present and take in all the splendour of this incredible cosmic alignment! Feel the temperature drop on your skin! Look around you towards the horizon to notice how the colour has changed! See if you can notice the change in animal sounds as darkness descends! Or maybe a breeze picks up because of the temperature change. And, when it is safe to do so, absolutely take off your glasses to see the solar corona once totality has begun (and put them back on as it’s about to end)! This tenuous, wispy gas is the hazy outer atmosphere of the Sun that can only be visible during totality. Remarkably, this gas is actually at millions of degrees and is still an outstanding question in solar astrophysics to understand how that temperature is maintained.

To me, just being a witness to an event that our ancestors must have seen, may have even frightened or worried them that something terrible was happening to our Sun, is a way to connect to our shared history. Events like these undoubtedly inspired many stories and mythologies; today we understand this cosmic dance so well that we know it as a rare event to be experienced, cherished, and shared with family and friends.

FIGURE 1: The Total Solar Eclipse on April 8, 2024 represents a once-in-a-lifetime opportunity to observe a rare celestial event. The path of totality will span the areas around Lake Erie and Lake Ontario in the south and will continue into portions of southern Quebec, New Brunswick, and Newfoundland. (Image courtesy of EclipseWise)

FIGURE 2: This map shows the small area of Ontario that is within the narrow band of Totality. The duration of the Total Solar Eclipse increases as you approach the red centre line. Note that areas to the north of this narrow band – for example, the cities of London, Mississauga, Toronto, and Ottawa – will only observe a partial solar eclipse! (Image courtesy of EclipseWise)

Location

Eclipse Start

Eclipse End

Duration

Kingston

3:22:14

3:25:22

3m 07.0s

Hamilton

3:18:11

3:20:03

1m 52.3s

St. Catherines

3:18:16

3:21:31

3m 15.2s

Niagara Falls

3:18:16

3:21:53

3m 34.4s

Buffalo

3:18:29

3:22:14

3m 45.5s

TABLE 1: The start and end times of the Total Solar Eclipse on the afternoon of April 8, 2024 is shown for a few representative cities in Ontario. NOTE: The City of Toronto will not experience a Total Solar Eclipse! (Data courtesy of EclipseWise)

FIGURE 3 (top): During a total solar eclipse, the Moon will pass in front of the Sun blocking sunlight completely, turning day into night. For areas in Southern Ontario, totality will last as long as 3 and half minutes! During this time, and only during this time, it is safe to remove your solar eclipse glasses to see the outer tenuous atmosphere of the Sun that is known as the corona. The wispy corona is a several million degree gas that is only visible during a total solar eclipse! (AP File Photo)

FIGURE 3 (bottom): For those not in the narrow band of totality, folks will see a partial eclipse where the Moon will block a significant fraction of the solar disc. Because the Moon will not block the Sun completely, it is never safe to remove eclipse glasses to look at the event directly! This image, taken with an appropriately filtered telephoto lens, shows an annular solar eclipse in progress over Toronto in 2021. (Frank Gunn/The Canadian Press)

 

BIOGRAPHY: Shanil Virani is an astronomer and a native Torontonian having graduated high school from Marc Garneau Collegiate Institute. He did his undergraduate work in physics at the University of Waterloo before pursuing graduate work in astrophysics at Yale University. He hosts a podcast called “Our Island Universe” and now works for the Astronomical Society of the Pacific (based in San Francisco, CA), an international non-profit scientific and educational organisation that works to increase the public understanding and appreciation of astronomy.