The sky was falling between St. Thomas and Aylmer last week, and the search is now on for bits of rock from out of this world.
A basketball-sized meteor hit the atmosphere March 18 at about 10:24 p.m. near Port Dover at a height of 75 km. The meteor, described as being "almost as bright as the full moon" lit up the skies as it fireballed across southwestern Ontario, moving almost due westward before ending at a 32 km altitude between Aylmer and St. Thomas.
The meteor was detected by seven all-sky cameras of the University of Western Ontario's Southern Ontario Meteor Network and two camera systems in Ohio and Pennsylvania jointly operated with NASA's Meteoroid Environment Office.
Peter Brown, director of the Centre for Planetary Science and Exploration (CPSX), said that, based on video records, at least one rock survived to the ground. They expect the meteorite fragments will be about the size of a golfball or baseball.
"This is the first time in about five years we've had a meteorite fall like this in southern Ontario. The last really spectacular fall in this category occurred near Grimsby," Brown said, referring to an impact from September, 2009.
Researchers made an appeal to the public on March 21 for help in finding any meteorite pieces. There is no real equipment that can detect fallen meteorites, which means the only way to find them is for people to get outside and use their eyes.
The search area is approximately 5-7 km north and north west of the limits of St. Thomas, and no further west than the 401.
Meteorites are usually recognizable with a dark black and scalloped exterior, and are usually denser than normal rock. They will often, but not always, attract a fridge magnet due to their metal content. In this fall, meteorites may be found in a small hole produced by their dropping into soil.
Despite popular depictions in the movies, meteorites are not burning hot and don't emit radiation. Meteorites are just rocks and safe to approach. However, researchers remind that meteorites should be handled with care so as not to damage their scientific content. It's best if people use gloves when handling meteorites, and the pieces should be placed in a clean plastic bag or container.
"It's going to be very difficult finding the needle in the haystack," said Phil McCausland, Assistant Professor and Meteorite Curator at Western's Department of Earth Sciences.
In Canada, meteorites belong to the owner of the land upon which they are discovered. Anyone searching should obtain permission of the land owner before going onto private property.
This particular meteor has some rare characteristics. Bill Cooke, lead of NASA's Meteoroid Environment Office said the meteor was in an unusual Aten-Class orbit, which means it spent most of its time inside Earth's orbit, closer to the sun than we are.
There has only been one other recorded fall in history from an Aten object, and that was in Australia in 2009.
"This is a very unusual orbit, so we're very interested in knowing what type of object was in this orbit," said Cooke. "If it's a eucrite, like this fall a few years back in Australia, then it came from the asteroid Vesta in the main asteroid belt, but we will not know that until we find a piece of it."
The main asteroid belt is located between Mars and Jupiter. Study of meteors can potentially help researchers understand how the solar system was formed.
Brown explained that meteorites are like a poor man's space probe. We don't launch meteorites; they come to us, but all the same they contain samples that can tell us about solar evolution.
"It's going to tell us about the things that made the early solar system. What made the Earth. What made the other planets," Brown said. "The real value in this rock is the science side of it. It's very unusual to have a fireball that produces a meteorite where you know the origin. That's only happened, maybe 20 times in the past. Each one of those is like a Rosetta Stone, telling us about the early solar system."
The fiery entry of this meteor was also detected by amateur astronomer Arthur Oslach, 73, of Aylmer. The camera on Oslach's roof caught digital video of the meteor as it passed over his house.
"I've had a number of incidents over the years. This is the biggest one. I'm so excited about this whole thing," Oslach said.
Oslach shared his data with Western University. Studying the sky has been Oslach's passion since he was in high school. Today he is a member of the Royal Astronomical Society.
"I do a lot of deep space work. Galaxies, nebula, going a long ways out into the universe. It's a thrill to me to see a galaxy 65 million light years away on my screen," he said.
Meteorite fall events are typically named after the community where they are discovered. If the meteorites are found closest to St. Thomas, Cooke said this could potentially be called "The St. Thomas Fall."
People who think they have recovered meteorites from this event are encouraged to contact Phil McCausland at 519-661-2111, ext. 88008 or on his cell at 519-694-3323. For updates, follow @mediawesternu and the hashtag #stthomasmeteor.