Date: November 7, 2009
Title: Bright Bolide
Podcaster: Michael Koppelman
Organization: Slacker Astronomy http://www.slackerastronomy.org/
Description: Michael, Doug and Mike from Slacker Astronomy discuss the bright meteor fireball (bolide) captured on multiple cameras by the Southern Ontario Meteor Network (SOMN) on September 25, 2009.
Bio: Slacker Astronomy is a light-hearted podcast that wanders the astronomical road-less-traveled. Visit us at http://www.slackerastronomy.org/.
Today’s sponsor: This episode of “365 Days of Astronomy” is sponsored by Skymaps.com producers of The Evening Sky Map, a 2-page monthly guide to the night sky. Free download from http://Skymaps.com.
Transcript:
Big Bright Bolide
Michael Koppelman: Hello again and welcome to 365 Days of Astronomy. I’m here with my Slacker Astronomy friends Doug Welch and Mike Simonson. We’re here to talk about a meteor event that occurred in Canada and was caught on all these cameras.
I’m just going to let Doug tell us what was going on. Doug what happened in Canada?
Doug Welch: Well it was in southern Ontario which many people think is all of Canada [laughter] but really isn’t. We have this meteor video monitoring network that Peter Brown from the University of Western Ontario set up.
One of the cameras is at McMaster and I’m the person that goes and kind of reboots it when it gets stuck. Mainly it just works on its own.
Every night it takes video all night and it records everything all night and saves it for up to three nights. It also has some very clever software where it looks for meteors and says, “I found one.”
The next day when other meteor cameras‚ similar files are checked they look for coincidences. If there are time coincidences it means it’s probably a meteor seen from various sites.
Then the orbit can be determined and if something is bright enough you can figure out actually where it might have landed.
Michael: I’m reading from your webpage here: “At 9:03 p.m. on Friday night, September 25, the seven all sky cameras of western Southern Ontario Media Network (SOMN) recorded a brilliant fireball in the evening sky over the west end of Lake Ontario.”
Is this a special event out of the ordinary?
Doug: It’s only about once a year do we get this combination of really, really bright meteor coming. It being clearer on a bunch of cameras and then actually having the potential fall zone being someplace nearby and accessible and agricultural.
Mike Simonson: Why is it particularly important that it be an agricultural area? Is it because you have a higher incidence of recovering pieces?
Doug: You have a higher chance to actually find things. If it’s very rocky, very mountainous, and very forested, then it is very tough to cover the area.
You really can’t ever narrow down the region to less than a few square kilometers [laughter] which ends up being a huge patch of ground.
This area was up in country, some of which is wine country, but farmer’s fields and right now a lot of the stuff is out of the fields.
It was almost a perfect event in terms of conditions for going to look for meteorites.
Michael: Before we get too far Mike it seems like you actually understand the terminology here. A meteoroid, a meteor, a meteorite an asteroid, how does that all work?
Mike: Well, a meteoroid is a small to boulder-size particle that’s basically debris floating around in the solar system.
Doug: It could be pebble-size too.
Mike: That’s right from sand to boulder-size is what I was trying to say. From a little piece to a boulder chunk, those are meteoroids when they’re out in space. When we see them burn up in the atmosphere we call it a meteor.
What is actually the meteor is just the path of the object burning up through the atmosphere. If it actually strikes the ground it becomes a meteorite, the pieces that actually hit the ground.
Some of these are extremely bright and they’re known as fireballs or Bolides.
Michael: This one was a Bolide and how bright was it?
Doug: It was about a hundred times brighter than the full moon.
Michael: Wow.
Doug: It was pretty amazingly bright. This is a very rare event. At any given place you might see one of these once a year if you’re looking all the time. [Laughter] It’s pretty rare.
Michael: Did you guys go looking for it?
Doug: We did. Because there were seven cameras that caught it we had a very good trajectory. We learned that it sort of stopped being luminous at about twenty kilometers above the ground, which is very low.
Normally meteors stop being visible at eighty or ninety kilometers up. There was infrasound generated from it. It was just the whole ticket for there are probably survival pieces, many kilograms worth.
We went to this area and I have to say it was a hoot. [Laughter] The team from Western had actually been doing their homework and finding out good places to search, talking to the landowners, getting permission.
There were eight of us on the day I went out which was probably the best day in terms of volunteerism. There were certain fields and we just walked across the fields in a grid looking for things on the ground.
We didn’t find any but it was great fun and because we had good video it had made all the news. [Laughter] So we had more reporters than we had searchers.
We were walking this line across the field and there were videographers walking backwards [laughter] photographing us. There was even a helicopter.
It felt a little like a cross between OJ Simpson and the X-files. [Laughter]
Mike: An astronomical media feeding frenzy. And you didn’t find a stone. [Laughter]
Doug: We found some golf balls which I have to say I thought were pretty peculiar. There were golf balls in the middle of this farmer’s field.
There were occasional pieces of slag too but no meteorites yet.
Michael: You’re sure they were terrestrial golf balls? [Laughter]
Doug: They had the characters written in strange runes on them. [Laughter]
Michael: When you’re looking for pieces in a field, what are the characteristics of the chunks that you’re looking for normally? Do they all look the same, are they different?
Can you predict what kind of pieces you are going to find or what you might be looking for or are you just looking for something that’s unusual? Are you looking for craters in the ground? What are you looking for?
Doug: That’s a good question. For one thing a lot of the stuff, not all of it, but the vast majority of the stuff that makes it through the atmosphere has sort of a black think crust on it called effusion crust. It’s sort of a black sheen.
These objects are in the atmosphere so briefly, seconds usually at most, that it’s only the tiny, tiny outermost layer that gets affected. But it does tend to have this blackish thing and that’s a giveaway.
If it had any fine points on the outside, those got worn away by encountering the atmosphere at twenty kilometers a second or higher [laughter] and the heat generated. After that if it is big enough, if it’s really big it makes a crater.
We don’t expect to find those. Even a minus seventeen object probably only produced kilogram-sized objects. Those might put a dent in the ground.
They might actually if the ground is wet and soft enough, might actually punch into the ground a few inches. We did look into any holes that looked like they were fresh in the ground.
Mainly they were animal holes or they had a regular Earth rock at the bottom. [Laughter] Then there were the strange finds like pieces of slag and golf balls.
Michael: Cool.
Doug: I did bring along a meteorite and I have to say I was tempted to throw it out and see if we could find it.
Michael: So dear listeners, if you Google “meteor” and “SOMN”‚ or if you like to type you can type in “Southern Ontario Meteor Network”, you will find the website that talks about these cameras, where they are placed, the fireballs they found so far, and what they are doing with them.
Doug: And some very cool video from our fantastic cameras.
Mike: The video is awesome. I was totally amazed [Laughter] I didn’t expect to see it like turn into this big thing that took up the whole field of view of the lens.
It looked like an atomic bomb dropping and burning up in the atmosphere over a city. It was really kind of spooky.
Doug: It certainly wasn’t a test of a long-range missile from a rogue nation. [Laughter]
Michael: Good to know. Well, there you’ve done it again; you’ve wasted ten minutes listening to 365 Days of Astronomy, but the best ten minutes of your day I bet.
Doug: Certainly the best ten minutes of mine.
Michael: Stop by and visit us at slackerastronomy.org; you can e-mail us at info@slackerastronomy.org . Stop by the blog, catch up on your road less traveled of Astro-space news.
Doug: Be sure and check out the photos from the Hamilton Spectator where I’m searching while modeling my Slacker Astronomy T-shirt.
Michael: I think we need to link that in somewhere. Until next time, this is Michael saying: “So long.”
Doug: Keep your head low, watch out for the meteorites.
Michael: Come on Mike, say something funny.
Mike: The sky is falling! The sky is falling! [Laughter]
This transcript is not an exact match to the audio file. It has been edited for clarity. Transcription and editing by Cindy Leonard.
End of podcast:
365 Days of Astronomy
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