Canadians will want to cast their gaze skyward this Saturday night, as fragments from the most famous comet in the solar system will put on a show in the Earth's upper atmosphere.
Our planet will be making its annual pass through the debris trail of Halley's Comet, allowing stargazers in parts of North America to watch in wonder as meteors streak across the skies.
The meteor show, called the Orionid meteor shower, lasts for about a week every year in October.
But it’s expected to peak just after midnight on Saturday night this year, giving Canadians ample time to see as many as 25 meteors per hour light up the sky.
As long as there are few clouds overhead, you’re pretty much guaranteed a great show of shooting stars, says York University astronomy professor Paul Delaney.
“This one is a really reliable meteor shower,” Delaney told CTV’s Canada AM Friday. “Some meteor showers tend to fizzle a little bit, but the Orionids is normally a very reliable shower.”
Delaney also says the moon is in the right position for optimal viewing this year; that is to say it’s in the first quarter, which means it will set around midnight.
“So the moon has done everything right for us.”
All you need to do to find it, Delaney explains, is to look towards the Orion constellation around midnight.
“It’s called the Orionid meteor shower because, when you’re looking into the sky, it looks like as if the stream is coming from the constellation of Orion, just past the star Betelgeuse.”
Delaney suggests heading out to an area that’s wide open on the east and southeast horizon – and on that’s as dark as possible.
“Look toward Orion, but be aware that the meteors could be anywhere, like a half a sky away from Orion,” he says.
The meteor shower should hit its peak around midnight ET.
“But it's not a one-minute affair. So after midnight Saturday night, for three or four hours, that would be the best time to view it,” Delaney says.
As for what’s responsible for the amazing shower of light, it all comes down to space rocks heating up and then literally falling apart.
“All comets, as they sweep into the sun, get heated up ferociously and they off-gas. And in the process of off-gassing, stuff comes off the rock,” Delaney explains.
Halley’s Comet – which, by the way, is pronounced so that it rhymes with “Sally” – is a big rock, as comets go. It’s about 10-15 kilometres in diameter and as gas comes off, so too do chunks of rock material.
“So it’s little pieces of debris left over from the comet as it’s literally disintegrating every time it passes by the sun,” says Delaney.
As for when we’ll get to see all of Halley’s Comet and not just its cosmic dust, that’s going to be a while: It won’t be visible in the night sky until 2061, 75 years after it last swept by Earth in 1986.
