[UPDATE: Turns out the fireball described below was the re-entry of the Soyuz booster that brought Expedition 30 up to the International Space Station a few days ago. Thanks to Marco Langbroek for alerting me to this!]

[Update 2 (19:08 GMT): More footage, and a picture in a Dutch paper. Tip o' the Whipple Shield to VirtualAstro and JHG Hendriks.]

Reports are coming in of a very bright fireball over Germany, Belgium, and the Netherlands. It happened around 16:30 GMT (17:30 local time in that part of Europe) on December 24 (just a couple of hours ago as I write this). I heard of it when BA Bloggee Dave Grant sent me a note from Dusseldorf; he got video of it!

If you are in that area and saw it, you can report it to the International Meteor Organization or to The Latest Worldwide Meteor / Fireball Reports (note: I found that last site doing a bit of searching and I’m not familiar with it, so I don’t know how official it may or may not be. There are links in the sidebar there to other organizations). make sure you list your position as best you can, and what direction you were looking.

If you did see it, and have pictures or video, please leave a comment below with a link! It’s a holiday, but I can try to post some of the better shots/footage. The more actual footage there is, the better astronomers can trace both the direction from which it came, and the location of any possible meteorites.

In August, I wrote about how you can listen to meteors: radar bounced off their ion trail can be converted to sound, making eerie, creepy noises.

Via astronaut Ron Garan comes this video of recordings made by the U.S. Air Force Space Surveillance Radar in Texas during the Perseid meteor shower. It’s very, very cool:

As I wrote in the earlier post, here’s how this works:

You’re not really hearing sound, of course: meteors burn up in our atmosphere at a height of 100 km or so, too high to directly carry sound waves. But the Air Force has a radar surveillance facility in Texas that beams radio waves into the sky. When a bit of cosmic fluff streaks through our sky, the ionized trail it leaves reflects the radio waves, producing an echo. This radio wave is then translated into sound, so you can effectively hear a meteor!

The initial "whoosh" is from the meteor itself, and the dying whistling sound is from the ionized gas it leaves behind, which slowly recombines and fades.

… which is all well and good, but science aside, all I could think of while listening to that was the soundtrack to Ren and Stimpy walking along the landscape inside the hideous vortex of the black hole.

Randy Halverson is a photographer who makes stunning time lapse videos of the night sky (like Tempest Milky Way and Plains Milky Way; seriously, if you haven’t seen those, go watch them now). He’s currently in the process of making a new video, and in one of the frames he happened to catch a bright meteor, a bit of cosmic fluff burning up as it rammed through our atmosphere. What’s neat about this particular incident is that the meteor left behind a glowing streak that lasted for over half an hour!

You can see it there, the red twisty worm at the upper left, across the glow of the Milky Way [click to enbolidenate.]

Technically, that’s called a persistent train, and it’s not actually smoke. As a meteoroid (the actual solid chunk of material) blasts through the air, it ionizes the gases, stripping electrons from their parent atoms. As the electrons slowly recombine with the atoms, they emit light — this is how neon signs glow, as well as giant star-forming nebulae in space. The upper-level winds blowing that high (upwards of 100 km/60 miles) create the twisting, fantastic shapes in the train. The actual details of how this works in meteor trains are not well understood, mainly because they are so difficult to spot and study. It’s hard to point a telescope at a position in the sky when you don’t know where or when a meteor will pass through!

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While the object in Peruvian skies may not have been a meteor, this thing certainly was:

That was a fireball — an extremely bright meteor — that blew in over Atlanta, Georgia on August 28. The video is from the webcam at the Tellus Museum of Science in Georgia, part of the All Sky Fireball Network (I wrote about them recently when this same camera caught the space station passing overhead, in fact). The other streak you can see moving is an internal reflection in the camera, I believe, which shows you just how bright this fireball was.

Since there are four cameras in the network, they could triangulate on the meteor, getting its height off the ground. Coupled with its apparent speed, that tells them it was screaming in at more than 83,000 kph (52,000 mph)! Given how bright it was, I suspect it was probably about the size of a grapefruit or so. Funny how something that small can make such a bright streak, but then speed is the key here. The brightness of a meteor depends on how much energy it can deposit in the atmosphere, and that is determined largely by its kinetic energy. That, in turn, depends on its mass and its velocity… and these things are moving far, far faster than a rifle bullet.

The Tellus webcam caught other meteors that night too, which you can see here. They’re getting lots of information about the debris that hits us. And since about 100 tons of material enters Earth’s atmosphere every day, there are plenty of interesting things to discover!

A few days ago, the web was abuzz with something that looked like a very large meteor burning up over Peru. Here’s video from ITN news:

You can find similar videos on Youtube. However, is it actually a meteor?

Cutting to the chase, I don’t think so. I don’t have a lot of solid evidence either way, but all signs point that way. Here are my thoughts:

1) Meteors tend to move more quickly. They usually burn up around 100 km (60 miles) up, roughly, and are moving at a minimum of 11 km/sec (7 miles/sec) — Earth’s gravity pulls them in to at least this speed. If you’ve ever seen a meteor you know they zip across the sky in at most a few seconds.

2) The two trains (the technical term for what most people would call the tail or trail) are very odd — you can see them in the frame grab here. I’ve never seen a meteoroid (the actual solid bit moving through our atmosphere) produce more than one train. I don’t think this is an optical effect due to the camera but actually two distinct trains.

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Randy Halverson is a photographer who makes incredibly stunning time lapse videos of the sky. And he’s done it again: "Tempest Milky Way", an aptly-named video showing the serene depths of the night sky as a background for furious activity much closer to home:

[Make sure it's set to HD, and make it full screen. You're welcome.]

Holy wow! It’s beautiful enough just showing the stars, but then at 2:20 things really get interesting as storms blow in. There’s lots to see, but keep your eyes open at 1:57 for the silhouette of a whitetail deer on the horizon, and at 3:24 for a meteor that pops into view… and is reflected in the lake!

It’s a breath-taking shot, isn’t it? And it’s a testament to Halverson’s talent, which you can see more of at his website DakotaLapse. I love how the motion of the camera (especially moving up through the corn field) adds a magical sensation to the video. And while time lapse photography like this shows us a dimension we can’t see easily with our own eyes, it’s real nonetheless. Never forget that: the Universe is beautiful, spectacular, and marvelous. Our job is to appreciate it, and try to understand it better.

Credit: Randy Halverson, used by permission.

Astronaut Ron Garan, currently on board the International Space Station, was taking pictures of our home world out the window — and how cool is it to be able to say that? — when he took this amazing picture of a meteor burning up in our atmosphere:

Wow! [Click to bolidenate.] How cool would it be to look down to see a falling star?

He took this shot (according to the header info in the picture) on August 13 at 7:17 p.m. UT, when the ISS was above the Mongolia/China border. This was during the annual Perseid meteor shower, but that doesn’t guarantee this meteor Ron saw was a Perseid. It probably was, though. For an observer on Earth, the Perseids rain down at a rate of about 60 per hour or so. You can usually see about 5 meteors per hour that are just random bits of cosmic detritus. So only 1 meteor in 12 is not a real Perseid, making it likely this one was.

But that got me thinking… [WARNING: math ahead. Cool, tasty, refreshing math that will lead to insight, wonder, potential party conversation (assuming you go to the same dorky parties I do), and other nifty things.]

Meteors burn up roughly 100 kilometers (60 miles) above the Earth’s surface. To make the math simpler, let’s say they burn up at exactly that height, so that any meteor coming in hits this barrier and evaporates. You can picture it as a thin shell of air surrounding the Earth 100 km high, like a force field, or better yet as an umbrella that rain hits (it’s a meteor shower, after all, ha!) and stops cold.

When you look straight up, that barrier is 100 km directly above your head. When you look to the horizon, that distance is actually a little over 1000 km away, because the atmosphere follows the curve of the Earth (you can get an idea of this in the diagram above). The top of this umbrella is then 100 km up and over 1000 km to the sides.

From the space station, though, looking down from orbit at a height of roughly 350 km, more of the atmosphere can be seen because the station is higher up (just like you can see farther if you go to the top of a building). (more…)