You'll be waking up to a shower of a different kind on Sunday as the annual Perseid meteor shower reaches its peak.
The comet Swift-Tuttle is passing overhead, trailing a cloud of 1,000-year-old debris, which is visible on earth as a meteor shower.
The Perseid cloud behind Swift-Tuttle is made up of water and methane ices, loose packed cometary material, soot and sand. It is usually visible from late July, and the peak of the shower occurs between August 9 and 14.
This year, the meteor shower will peak for about two and a half hours on Sunday morning, August 12, from 6 a.m. to 8:30 a.m. MDT. - unfortunately, just as dawn starts to lighten the sky so you should get up early to see some of the action.
But the meteors will be visible all weekend, according to Rick Nowell, physics lab tech at the College of the Rockies, where a meteor camera captures out-of-space activity.
"The shower should be fairly active, exceeding 30 meteors an hour, for three nights from August 11 to 13. During the peak two and a half hours, we should see an average of 100 meteors per hour, or a meteor every 36 seconds.
"The brighter Perseids are around one to two inches in diameters. Others are just specks and grains of sand."
The debris from Swift-Tuttle is travelling at around 60 kilometres a second, Nowell explained.
"That's Mach 176, which makes a jet aircraft doing Mach 1 look like a snail, since Mach 1 is just 0.34 kilometres a second."
These meteors are travelling too fast to get all the way through the atmosphere without breaking up - they burn up between 104 and 90 kilometres above the earth and never hit the ground. It's only asteroid-type meteors made up of solid rock or nickel and iron that travel slow enough at less than 23 kilometres a second to impact the earth.
Cranbrook has already started to see a few meteors from the Perseid cloud, with a large one that looked about as big as the moon caught by the College's fish-eye rooftop camera on Thursday, August 2 at 1:52 a.m.
Nowell described what happens when a piece of the comet's debris hits Earth's atmosphere.
"First the fast meteor begins to heat the thin air around it into a glowing plasma, then when it hits higher density air, it disrupts into a ball of incandescence, the outside layer breaking off, leaving pockets of glowing light debris behind it, the smaller, denser interior shooting ahead, in turn disrupting under the tremendous deceleration and heating into a short glowing line, before slowly fading away."
The path of Swift-Tuttle's orbit means that the Perseids are mostly visible in the northern hemisphere, and mostly in the pre-dawn hours.
Adding to the Perseids light show are two other astronomic events currently going on above our heads.
The Delta Aquariids, which started in mid July, are still visible. Those meteors come from the break-up of comets Marsden and Kracht Sungrazing.
And the Kappa Cygnids are expected to peak one day after the Perseids, on August 13. This minor meteor shower is named for the radiant when the shooting stars appear in the sky near the star Kappa Cygni.