Until a few decades ago, it was unusual for a meteorite even to be recognized as being connected with a particular meteor event in the sky. But camera technology, sky surveys, and sophisticated software have changed all that. Analyzing a photographic record like the Golden meteorite blazing a trail over Alberta and British Columbia is almost routine nowadays. In short order, the meteor physics group at Western University had the Golden meteorite pegged…
Let’s look at this through the vision of the space rock. Be the asteroid, so to speak. It’s been out there between Mars and Jupiter since the very beginning of the solar system, looping the Sun on a long and lonely path to nowhere, and it’s no bigger than a prairie tumbleweed. A gentle nudge about half a billion years ago (thank you, gravity), and its fate was sealed. Round and round until, on the night of the October 3, 2021, it lined up on this blue planet and, smash. Bang. Pow!
The boulder broke up spectacularly over the Rocky Mountains and dropped its chunks on the sleeping town of Golden, British Columbia. Not that gold was ever mined there, but let’s tell ourselves that a space rock, which also contains no gold, is a better strike than any prospector’s gold-rush dream could ever be. And though a vast number of rocks smaller than this one hit the Earth’s atmosphere and vapourize every hour of every day, as well as an occasional bigger boulder, this one had better aim. It did something that happens only very rarely: it almost killed a human being.
Thank goodness for the almost! Ruth Hamilton was safe asleep in bed, like most good citizens of Golden, about a half hour before midnight. Falling more-or-less vertically downward from a spot more-or-less 19 kilometres above, where our atmosphere had more-or-less slowed the rock to zero, it crashed through the roof of Hamilton’s house. There was enough punch left in it to tear a hole through a metal sheet, asphalt shingles, plywood, and a drywall ceiling. More-or-less four billion years in space, and its voyage ended rather softly on Ruth Hamilton’s pillow. More-or-less right next to her head. “That could have hit me,” she said when interviewed by a news reporter. “Thinking of that just makes my heart race.” A meteorite has never hit a person’s bed in Canada before. If she’d been any more lucky, the meteorite would have missed her house completely.
Who you gonna call? At first thinking that the crash she heard was an explosion, Hamilton dialled 911, and the local RCMP sent over an officer pretty quick. By the time the officer arrived, Hamilton realized there was a rock on her pillow that didn’t exactly belong there. Being directly below the hole in the ceiling was the clue. The rock was probably more confused than they were, given that there are no pillows in the asteroid belt.
1.3 kilograms by weight, it was the size of a softball, but shaped more like a brick, with a dark surface that looks like crinkly charcoal. Darker than what you would find just about anywhere in those Rocky Mountains. The surface is actually just a thin fusion crust, crisped by the heat of friction with the upper atmosphere as this chip of the cosmos slowed down from its entry speed of 18 kilometres per second. Most meteors come zooming in even faster than that, actually. It does take a lot of heat to fry that thin wrapper of rock, but remember the chunk came from outer space, where it was a couple hundred degrees below zero for a very long time indeed, and it only spent a few seconds braking in the atmosphere. Its insides didn’t have time to feel the heat. Almost never is a meteorite burning hot when it kerplops on the ground.
On the outside, for those dramatic moments of deceleration, the heat energy on the surface of an incoming space rock gets very efficiently converted into something completely familiar to every Canadian who has spent a sombre summer evening under the stars: the sizzly streak of a meteor across the sky. Ruth Hamilton’s meteorite was the happy ending for one of those. In fact, the Golden meteor was widely seen that night, and as memorable as a Robert Service poem. The RCMP officer first called a construction project up the road from Golden, where he figured they might have done some blasting. They said no, there had been no dynamite but, heh, did you see that bright flash coming down over the mountains?
Over by Lake Louise, about 50 kilometres from Hamilton’s neighbourhood, a photographer named Hao Qin sure saw it. He was shooting a night-time video of the Milky Way reeling over majestic Mount Whyte. In a stunning still frame from his video, the parent asteroid of our plucky space rock arrows in from the corner of the frame. No mistaking what happened, and the precise tracking of the starry background provides exactly the reference that scientists require to calculate backwards and figure out where in the sky the meteor came from. It came in on a 54-degree angle, which is steeper than the average meteor. In Calgary, two security cameras and the dash cam on a car caught the fireball on video. All of these were soon analyzed and combined with the information from some frames shot by dedicated meteor cameras at the University of Calgary.
There was more. Eyewitnesses in the region reported that they saw the fireball break into flaming pieces. A security camera at the Sunshine Ski resort in Banff verifies this. So researchers at the University of Calgary did a computer simulation of the trajectory and suggested that smaller pieces probably dropped in a zone north of Ruth Hamilton’s house, on the other side of Canada’s longest authentic covered timber-frame pedestrian bridge.
Two of the scientists, Alan Hildebrand and Lincoln Hanton, drove over from Calgary and, with the keen eyes of geologists, soon spotted a chunk on a roadway. This is real science, after all, not a cheap reality tv show. And in Canada, the legal framework says a meteorite is a “culturally significant object,” but on public property it goes to whoever finds it. Score one for the University of Calgary collection. Their rock is not quite as hefty as Ruth Hamilton’s extraterrestrial visitor, but different in a curious way: whereas Hamilton’s piece is completely covered by the black fusion crust, the second piece broke open in the last moments before it landed. Thus, the rocky interior was revealed. It’s a distinctly lighter gray colour with a mottled appearance like cream of mushroom soup. A significant fraction of all meteorites, called chondrites, have this same kind of interior. In space, they’re pretty ordinary, but they are older than even the oldest rocks that have ever formed over the aeons on the surface of the Earth.
Seen from way out in space, the breadth of Canada must make a good target. In 1994, after a meteor lit up the sky near St Robert, Quebec, the CBC reported that Stéphane Forcier saw a congregation of cows all looking at a hole in the ground with a fresh meteorite in it. What were they thinking? In 1998, in broad daylight at the Doon Valley Golf Club in Kitchener, Ontario, a meteorite whizzed by Orville Delong and landed near him. The golf club granted him a year’s free membership. In 2002, a shower of fragile clods of space dirt landed on the frozen surface of Tagish Lake on the Yukon-BC border, and scientists were ecstatic about it because the frigid weather minimized earthly contamination of the meteoritic material. In 2009, Tony and Yvonne Garchinsky’s pickup truck, sitting in their driveway in Grimsby, Ontario, took a meteorite off the front windshield, although they didn’t realize what it was until after they had replaced the glass. Which is a shame because targets that are hammered from space fetch good prices from rich folks who collect odd things like that. If you tried to pitch these tales in Hollywood, they would scoff.
But let’s get back to Ruth Hamilton and the Golden meteorite. Despite all the misconceptions harvested in Hollywood, Hamilton and the RCMP officer scoped out its nature pretty quickly. Hamilton checked online and soon reached out to Western University in London, Ontario. They have a website that explains much about the astronomical significance of meteorites. The photo Hamilton sent impressed Phil McCausland at once. “I already knew it was a meteorite,” McCausland said, before he contacted her. Being curator of Western’s meteorites, McCausland sees plenty of plain boring rocks that folks bring to him. Experts, being only slightly better than the rest of us humans, can’t resist calling these imposters “meteor-wrongs.” Not this one! McCausland also discussed naming the meteorite with Hamilton. Tradition dictates that a meteorite takes the name of the nearest post office or memorable topographical feature and Hamilton agreed that “Golden” will be a tough name to top. The designation was officially announced in late 2022 by the international authority on meteorite names, the Meteoritical Society.
Hamilton offered to let McCausland study the interloper in his lab. It certainly deserves the status of “rock star” more than any talented musician ever did! In London, they scanned it with x-rays, the idea being to reveal its internal secrets without having to smash it open. In particular, scientists look for small spherical inclusions of metals called chondrules. Most meteorites have them. Chondrules are blobs that coalesced before the Earth and planets were even around, when the Sun was embedded in a vast disk of swirling gas. As cosmic time went by, the chondrules got clumped together, some of them remaining stuck in the asteroids while others were absorbed and melted into the planets as they formed. The Golden meteorite has the chondrules, as expected. McCausland explained that, to establish scientific recognition, a small sample of “Golden” has to be kept in an established research collection. Hamilton allowed the lab to slice off a small piece, about 43 grams, with a tungsten wire saw. The sample will be preserved with many others in Western’s archive.
There’s an active global market for meteorites, made up of private collectors and museums as well as university labs and government research departments. In the scientific community, meteorites are often traded or shared so researchers can access them for study. The rest of us can find them at gem shows or on eBay any time, with common examples, authenticated but not really special, fetching something around ten dollars per gram. The price goes up from there, depending on how interesting or unusual a meteorite is acknowledged to be. Given its weight, and with its fabulous backstory, the Golden meteorite might be worth a solid fraction of a million dollars. It’s permitted for any privately-owned meteorite in Canada to be sold, but, in principle, the federal geological survey has to be told if it leaves the country. That decision is now in Hamilton’s hands.
The question of where the Golden meteorite came from can also be answered now. Until a few decades ago, it was unusual for a meteorite even to be recognized as being connected with a particular meteor event in the sky. But camera technology, sky surveys and sophisticated software have changed all that. Analysing a photographic record like Golden’s blazing trail over Alberta and British Columbia is almost routine nowadays. In short order, the meteor physics group at Western had the Golden meteorite pegged. Its path around the Sun obviously crossed the Earth’s orbit, which makes the Golden meteorite an example of a near-Earth object, or NEO. Like all NEOs and the planets themselves, Golden’s orbit was an ellipse, with its greatest separation from the Sun beyond the orbit of Mars. But the Golden meteorite is slightly unusual in that most objects of this type travel a bit farther out than that, in the region known as the asteroid belt. That’s why the expert conclusion is that it was tugged from a longer orbit by an earlier approach to one of the four inner planets that we all know.
Ruth Hamilton’s grandchildren will talk about this for a long while, as humans measure time and thrills. For the Golden meteorite, it’s just another page in a much longer story. Cheers to you, little space rock.
Editor’s note: This article was contributed to SpaceQ by Peter Jedicke, an active amateur astronomer. SpaceQ accepts contributed articles on any topic covered by this publication. Please contact us by email at contactsq AT spaceq.ca.