In a rare combination of celestial events, the height of the Perseid meteor shower and the last supermoon of 2022 will dazzle the sky this Thursday night.
While delightfully unprecedented, this particular pairing may be a blessing and a curse.
“You will see meteors, but not as many because the light from a full moon is so bright that you could read a newspaper under it,” said Don Hladiuk, a fellow of the Royal Canadian Geographical Society.
“The light from the moon, which is reflected sunlight, will light up the sky so much, that many of the faint meteors that we would see when we get away from city lights, will be washed out.”
A supermoon occurs when the moon is closest to Earth in its orbit. This position is called the perigee. The proximity, relative to Earth, makes the moon seem bigger than usual.
The best times to view the meteors are after sunset and before sunrise. This is the time when the supermoon will be at its dimmest.
When the moon is closer to the horizon, its light is dimmer because it has to travel through more atmosphere to reach our eyes. It’s the same phenomenon that makes the moon appear yellow when it’s rising and setting.
A dazzling light spectacle
Luckily for the avid stargazer, the Perseids will be visible until the end of August. There will still be chances to catch some meteors streaking across the summer sky, although they are sure to diminish in numbers as each day passes.
The best places to view the meteors are away from light pollution. If you’re able to escape city lights to a campsite, to the mountains, or even to a small town outside of Calgary, you’ll have the best view!
Keep your gaze towards the constellation Perseus, which can be found in the northeast part of the sky during dusk hours.
Roughly 60 meteors crash into Earth’s atmosphere per hour during the Perseids. This is the second biggest of the year, second only to the Geminids, which sees about 75 meteors per hour.
Meteors travel at hypersonic speeds, five times the speed of sound or greater. The stellar debris travels at anywhere between 10,000-100,000 km/h when colliding with the atmosphere.
“When they hit our atmosphere, it’s almost like hitting a brick wall,” said Hladiuk.
“[Meteors] are hitting those oxygen and nitrogen molecules, and they will basically vaporize in the sky, producing a plasma tunnel. This is a very tiny tunnel of light, and it heats up to the point where it becomes plasma for just a fraction of a second. That’s why we see this beautiful streak of light in the sky.”
Cometary origins
The origin of the Perseids come from a comet called Shift-Tuttle. As the comet approaches the sun in its orbit, the comet heats up, and through a process of sublimation in the vacuum of space, the ice is transformed into a gas. This gas is what produces a comet’s famously beautiful tail.
Among those gas particles are also bits of dust, and those dust specs are left behind as debris when the comet heats up. Every August, Earth intercepts that debris cloud. It’s why we see the Perseids around the same time each year.
“[Swift-Tuttle] is about 26km in diameter, which is big for a comet. The more surface area, the more possibility of releasing gas and dust. So, that’s why we think the Perseids have been around for so many years, and is really popular in the summer, because it has a really good source of cometary debris,” said Hladiuk.
There are many other celestial events to look forward to even if you miss these spectacles. The Rothney Observatory, which is located south of Calgary, is hosting public events for viewing the Milky Way as well as Saturn’s closest approach to Earth.
