Tag: meteor

A persistent Orionid

By Phil Plait | October 25, 2012 7:00 am

Last weekend the Orionid meteor shower peaked. To be honest, it’s a rather weak shower, with a max of maybe 25 meteors per hour. I mentioned it on Twitter and other social media, but it’s usually a so-so shower at best so it didn’t seem worth it to plug it much. Even big showers like the Perseids, Leonids, and Geminids can be fairly variable in what you see, so I usually only plug the bigger ones.

Still, the Orionids can be nice if you have dark skies. Mike Lewinski went out to Embudo, NM (along the Rio Grande river) to do some meteor photography and happened to catch a spectacular fireball from the shower. It even left what’s called a persistent train, a trail of ionized, vaporized material that can glow for quite some time. I combined three of his images into one composite to show you the sequence:

On the left is the fireball, in the middle is the glowing train (as well as a second meteor that fell along the nearly same path as the first), and on the right the trail some minutes after the original meteor. He said the train was visible for over half an hour! He also put together a time lapse animation of it:

[Note: You may need to refresh this page to see the embedded video.]

It’s pretty fast, so you might want to run it a few times. Mike also created a second video that’s zoomed in.

I guess the lesson here is that it can’t hurt to go out and observe meteor showers (here’s a site where you can see when the next one is). You might catch something pretty amazing! And even if you don’t, it’s still a night out under the stars, and that’s still one of the best ways you can spend your time.

Image credit: Mike Lewinski, used by permission


Related Posts:

- Like two trains passing in the night… a year apart
- A meteor’s lingering tale
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- Time lapse: Under the Namibian Sky

CATEGORIZED UNDER: Astronomy, Cool stuff, Pretty pictures

Moonbow, Milky Way, meteor

By Phil Plait | October 21, 2012 7:00 am

If you’ve read this blog before, then all I really need to tell you is that Thierry Legault took a picture.

See?

While in Queensland, Australia, Thierry took this shot of Wallaman Falls. While the Milky Way shone down, a meteor zipped past, adding to the drama. But what’s that at the bottom? A rainbow? At night?

Yup. Well, kinda. It’s a Moonbow, the same thing as a rainbow but with the Moon as the light source. Well, and it’s not raindrops that cause it, but aerosolized water droplets acting as little prisms, breaking the light up into the usual colors. Moonbows are very faint, but they show up in long exposures like this one.

Leave it to Thierry to not be satisfied with just our galaxy, a bit of interplanetary debris vaporizing, and a waterfall in his shot. Amazing.

He has more pictures from that trip, and yeah, you want to see them. His photos have been on this blog so many times I can’t even list them, but check out the Related Posts below, click the links, then click the links at the bottom of those posts (or you can use my search engine). It’s a journey that’ll widen your eyes.

[UPDATE: Thanks to pixguyinburbank on Twitter, I learned of a wonderful video about moonbows put out by the folks at Yosemite National park in the US. It's so good I'll just add it here so you can see it. Fantastic!

Enjoy!]

Image credit: Thierry Legault, used by permission.


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CATEGORIZED UNDER: Astronomy, Pretty pictures

Bright fireball lights up northern California

By Phil Plait | October 18, 2012 9:03 am

On Wednesday evening, October 17, around 19:45 local time, a bright meteor blazed across the sky of northern California. Some reports say it was as bright as the full Moon, and there were reports of loud booming noises as well!

Wes Jones of Belmont got this spectacular shot using a fish-eye camera (posted on the NASA/Ames CAMS site):

For comparison, to the upper left of center is Altair, and to the lower right is Vega, two of the brightest stars in the sky! Clearly, this was an intense meteor.

The best video I’ve seen so far is from the Lick Observatory, though it’s out of focus because the camera was newly installed and hadn’t been adjusted yet:

As the meteor flares (possibly due to the main body of it fragmenting) you can see the dome of the telescope on the left in silhouette. Another video from the observatory only shows it for a moment, but you can see it fragmenting.

Local TV station ABC7 has spectacular pictures, but I haven’t been able to confirm them yet.

A lot of folks are speculating that this is part of the Orionid shower, which peaks this weekend. The direction and timing for the meteor are wrong for that though, so it’s certainly not an Orionid. Meteor showers generally don’t make fireball like this. Also, showers are pretty frequent, so any random bright meteor has a decent chance of occurring during one just by coincidence. So be wary of claims like that.

The noise reports appear to be real, though. Some people say their houses were shaken like in an earthquake. This means the meteoroid (the solid part ramming through our atmosphere) was of a decent size (like a beachball, maybe? Hard to say) and got low enough in the atmosphere to have the sonic boom carried by air. Most small meteoroids burn up 100 km or so above the Earth, so no noise is heard. The noise coupled with the obvious fragmentation mean that there may be meteorites that hit the ground from this event. It’s not yet clear if it fell over the ocean or not, so I’ll try to keep up with the news and update this post as I find out more.

If you live in the US and ever do see a fireball, it’s a good idea to note the direction it’s traveling and your location as best you can, and then report it to the American Meteor Society. If you get pictures or videos, send them to me! I’d love to post them if I can.

Picture credit: Wes Jones and the NASA/Ames CAMS site.


Related Posts:

- VERY bright and spectacular meteor seen over northern UK! (and this update)
- Video of the daylight California fireball
- Best video of Soyuz rocket burning up so far
- … and a real meteor over Georgia

Like two trains passing in the night… a year apart

By Phil Plait | October 13, 2012 7:00 am

Randy Halverson is no stranger to the BABlog: his astrophotography is fantastic, and his time lapse videos stunning.

Last year, in early October, he was taking frames of the night sky for a time lapse video when he caught a bright meteor that left what’s called a persistent train: a trail that continues to glow for several minutes. He sent me a note about it, and I wound up writing a blog post about this relatively rare event.

OK, cool enough, But then, just a few days ago, he emailed me again: while out filming at the same exact location, he saw another meteor that also left a persistent train, almost exactly a year after the first one! It’s a funny coincidence.

Here’s the new shot:

[Click to ablatenate.]

This picture was taken in central South Dakota. The Milky Way dominates the dark sky here, and the trees provide a nice silhouetted foreground.

You can compare it to last year’s meteor here. Given the Milky Way in the frame, he was facing south to take these, and the more recent shot was taken later in the night, since the galaxy had rotated a bit compared in last year’s picture. If I were really nitpicky I could probably even calculate just how much later in the night it was using the angle of the Milky Way. To my eye it looks like about an hour.

Anyway, both meteors were probably what we call sporadic: just random bits of rock orbiting the Sun that had the misfortune to be in the wrong place at the wrong time. In this case though one meteor’s poison is another man’s meat. It was too bad for those interplanetary bits of flotsam, but very nice for Randy and for all of us… twice.

Image credit: Randy Halverson, used by permission.


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CATEGORIZED UNDER: Astronomy, Pretty pictures

UPDATE on the big UK fireball

By Phil Plait | September 26, 2012 7:00 am

There’s been a bit more news on that amazingly bright and weird fireball seen moving across the skies of northern UK last week.

Marco Langbroek is a paleolithic archaeologist in Amsterdam, and also an amateur satellite tracker – though with modern tech, the term "amateur" is arguable. Anyway, he’s been looking at the track and velocity of the meteor using eyewitness accounts (and the video taken), and thinks he can rule out the cause being the re-entry of human-made debris from a spacecraft. In fact, he thinks the meteoroid (the term for the actual object responsible for the light show) was an Aten asteroid: part of a class of rocks that orbit the Sun on paths that tend to keep them inside Earth’s orbit*.

The key issues here are the slow speed it moved across the sky, and the fact it moved east-to-west. That last part is really important: very few satellites orbit retrograde, or in that direction. Most orbit either prograde – west-to-east, the same direction the Earth spins and also the same direction it orbits the Sun – or in polar orbits (north/south). So right away that makes it unlikely the meteor was from a spacecraft.

However, what has me scratching my head is the slow speed of the meteor. A rock orbiting the Sun retrograde means its velocity will add to the Earth’s, making it move faster as it burns up, not slower. It’s like two cars in a head-on collision; if each is moving 100 km/hr then the resulting collision speed is 200 km/hr relative to either car. You get slower relative collisions if they’re moving in the same direction; they’ll merely bump at low speed relative to one another.

We see this with meteors; the Leonid meteor shower, for example, is made up of tiny particles that move almost in the opposite direction of the Earth, and when they burn up in our atmosphere they move extremely rapidly across the sky. The collision speeds can be 70 kilometers per second!

So why was this meteor over the UK moving so slowly if it were an Aten? Marco thinks he has the answer to that. If the asteroid happened to be at aphelion – the top of its orbit, when it’s farthest from the Sun, also when moving most slowly and in a direction nearly parallel with that of the Earth – it would all add up. The backwards direction and the slow motion would be a natural consequence of this. [UPDATE: I made an error here: the asteroid can orbit the Sun prograde! When it's at the top of its orbit, it can be moving slower than Earth does around the Sun, so when we look at it it appears to move east-to-west. It's like passing a slower car in a faster one; to the driver of the passing car, the slower one appears to be moving backwards when in reality they are both moving in the same direction. I hope that clears up any misunderstanding!]

I’ll note that as far as I have thought about this, I agree with Marco. It’s not conclusive yet, though, but it’s compelling.

Meteors like this are rare. One that gets this bright, is seen by so many people, and drops bits of itself as it burns up are rare enough (the Peekskill meteor in 1992 is the best example of this), but one moving retrograde is even weirder. If Marco is right then I hope even more people submit their observations, pictures, and videos to the International Meteor Organization website. Those observations can help scientists determine the orbit of the object more accurately, and help pin down exactly what the heck this crazy object was.

Image credit: Craig Anderson


* Technically, an Aten asteroid has a semi-major axis less than one Astronomical Unit. Orbits are elliptical, and the semi-major axis is the half-diameter of the orbit along the long axis. Despite this, an Aten can cross the Earth’s orbit if its orbit is elongated (eccentric) enough.


Related Posts:

- VERY bright and spectacular meteor seen over northern UK!
- Video of the daylight California fireball
- Best video of Soyuz rocket burning up so far
- A meteor’s lingering tale

CATEGORIZED UNDER: Astronomy, Cool stuff

VERY bright and spectacular meteor seen over northern UK!

By Phil Plait | September 21, 2012 5:27 pm

Twitter just exploded with reports, pictures, and videos of an extremely bright fireball moving over the northern part of the UK at around 22:00 UTC. I’ve seen tweets from folks in Ireland, Manchester, and more. It was traveling east-to-west, and broke up into many pieces as it fell. No reports of it hitting the ground yet, though some pieces may fall all the way down.

Here’s the best video I’ve seen so far:

Other videos are not as clear but do show the same object (note the positions of the individual pieces as they move). Here’s one from Ross Shankland:

and another by Rowan Kanagarajah:

Here’s a picture from @Mr_Danger:

It’s too early to tell, but this may be a actual meteor – that is, a rock burning up – or it may be space debris, a piece of a satellite re-entering. Meteors tend to move quickly, zipping across the sky in a few seconds; they are moving at 20 – 50 kilometers per second and sometimes more. Orbital debris is slower, moving at less than 10 km/sec. Both have been known to break up (like the Peekskill meteor did, or the re-entry of an ATV in 2011).

I’ll update this as I get more info. But I have to say how jealous I am of everyone who saw this! And if you did witness it, you should file a report with the IMO, so they can collect all the info – it may help lead to finding meteorites, pieces that have made it all the way down to the ground!

My thanks to everyone who tweeted links to the pictures and videos.

MORE ABOUT: fireball, meteor

Did a meteor plunge into the ocean near Perth? I'm thinking no.

By Phil Plait | July 2, 2012 10:30 am

I’ve been getting some emails and tweets alerting me to photos that purport to show the debris trail of a meteor after it apparently plunged into the ocean off the coast of Perth, Australia. After looking at the pictures, I’m pretty sure this is not a meteor, but an airplane contrail.

First, the picture, from the Australian news site News.com.au:

It’s a lovely photo! It shows the ocean off to the west of Perth, a blue sky, and what appears to be some sort of cloud-like vapor or debris trail. That’s probably not just an average cloud: it’s very linear, and shows signs of being sheared apart by winds. Cirrus clouds can look like this, but generally aren’t all alone in a blue sky. There are other types of linear clouds (like alto- and cirrocumulus) but those tend to appear in parallel bands.

The cloud is also relatively low above the Earth’s surface. In another photo from news.com.au, you can see the faint shadow of the cloud on the sky – I have inset that here, with the brightness and contrast stretched. The arrows mark the shadow (the bright blobs are most likely internal reflections in the camera, and the dark spot a piece of dust or something like that on the lens). The picture was taken at sunset, so the Sun was low. The shadow of the trail is being cast on haze and other stuff floating in the air above the cloud. Clearly, the trail isn’t all that high above the Earth’s surface.

This doesn’t mean it’s not from a meteor, necessarily. A big rock plunging into the ocean might leave a trail (technically called a "train") like this. But I don’t think that’s what we’re seeing. A big rock burning up in the atmosphere would’ve been really conspicuous, and seen by lots of people – especially at sunset near a major city like Perth. I’d also expect the train to be much longer than this; big meteors start burning up about 100 kilometers (60 miles) over the Earth, so the train would arc across more of the sky.

And no one saw that? Also, there are no confirmations from anywhere else of an impact or even observations of this. So my skeptic sense is tingling hard.

Also? It just really really looks like a typical airplane contrail! We see these all the time. When a plane flies over the horizon it can leave a contrail looking exactly like this, with perspective making it look like it’s diving down into the ocean. It gets lit by the setting Sun, so it glows red, orange, or yellow. Thinking parsimoniously – using Occam’s razor and looking at probabilities here – what’s more likely: an airplane flying away from a big city, or a big rock burning up in our atmosphere that almost no one saw?

Furthermore, contrails have been mistaken for meteors and even missile launches in the past!

And I’ll save the best for last: as I was wrapping up writing this post I did a Google search to see if anything new popped up, and sure enough there’s an article with a witness saying he saw this cloud for a while before sunset, and it was clearly a contrail from an airplane. I don’t put a lot of stock in eyewitness testimony in general, but that fits everything else we know.

So it seems far, far more likely to me that what we’re seeing here is a contrail from an airplane being lit up in a lovely and spectacular way by the setting Sun, and not the smoky path of a bit of cosmic debris meeting its fate Down Under. That may not be as exciting, but it does help in a way: once you understand better what you’re seeing in the sky (or in this case, not seeing), then you’ll be in a better position to make a judgement if you do see something truly unusual. They may be rare, but spectacular meteors do sometimes flash across the sky. If you’re fortunate enough to ever see one, wouldn’t you rather be sure that’s what you’re seeing?


Related Posts:

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MORE ABOUT: contrail, meteor, Perth

Video of the daylight California fireball

By Phil Plait | May 31, 2012 6:00 am

On April 22, 2012, a chunk of asteroid one or two meters across burned up in Earth’s atmosphere. It came in over California and was seen by a lot of people, despite it occurring at about 8:00 a.m. local time and in broad daylight.

I just became aware that some footage was taken of the event, and as far as I know is the only video we have of it. It was taken by Shon Bollock, who was making a time-lapse kayaking video just outside Kernville, California as part of his Shasta Boyz adventuring website:

Pretty cool! It looks like he caught the very beginning of it burning up in the upper atmosphere. Not long after this, the meteoroid broke apart, raining down small meteorites onto the ground which were later found spread over the countryside.

The video is being studied by astronomers and meteoriticists to try to calculate the trajectory, speed, and possible orbit of the object. This is difficult with just one video, so if you have pictures you took or, better yet, more video, please let me know!

Tip o’ the Whipple Shield to Aaron Johnson on Twitter.


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Meteor, Crater

By Phil Plait | April 25, 2012 9:12 am

Brad Goldpaint thinks he’s the luckiest guy on Earth. He says that because he’s a photographer, and he was thrilled that after waiting a long time to get a good shot at Crater Lake, Oregon, the weather cleared up just in time for annual Lyrid meteor shower.

It’s hard to argue, especially when he says he saw only one meteor the whole night… and it looked like this:

Nice! [Click to calderenate.]

Crater Lake is an ancient volcano of such surpassing beauty that it’s no exagerration to say that when I visited there years ago, it changed my outlook on life.

The Lyrids are a weak meteor shower occurring every year in April. The shower does sometimes produce bright fireballs like the one Brad captured above, but usually most of the meteors are relatively faint. By the way, that fireball you may have heard about over California a couple of days ago happened during the Lyrids, but that was almost certainly a coincidence; that exploding chunk of rock was the size of a car when it came in, while meteor shower meteoroids are usually smaller than a grain of sand.

Anyway, I disagree with Brad. He’s not lucky. By taking so many pictures, by persevering, by always being out there, eventually this wonderful happenstance was inevitable. He made his own luck; chance favors the well-prepared.

By not-a-big-coincidence, this image was also on APOD today! Check out the Related Posts just below for more of Brad’s astonishing sky photography.


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CATEGORIZED UNDER: Astronomy, Pretty pictures

Time lapse: Epic Skies

By Phil Plait | February 20, 2012 7:00 am

Photographer Tony Rowell sent me a link to a time lapse video he made of the American southwest. It’s all really very pretty, but honestly, the part that got me was the amazing lenticular cloud at the very beginning. You just have to see it to believe it!

Spectacular, no? Lenticular, or lens-shaped, clouds form near mountains, where the rising air condenses to form the clouds, and the wind gives them their shape. I see them commonly here in Boulder, but near sunset the colors are magnificent. Tony really snagged a great shot there, and I love how it looks like a jellyfish hovering in the air.

Finally, right at the end (at the 4 minute mark) he caught a bright fireball over Mt. Whitney that’s just stunning.

It appears over several frames of the time lapse, which isn’t actually possible: meteors move so quickly they come and go in a single frame exposure (or at most just a few, depending on the exposure times)! I asked Tony about it, and he acknowledged that the meteor was slowed down after the fact in the video so you get a better view of it. I expect some people might think this is cheating, but I wouldn’t agree. After all, a time lapse itself might be considered cheating! It’s an artistic representation of reality, and I think it’s OK to let the art triumph, as long as it’s clear that’s the case.

Credit: Tony Rowell, used by permission.


Related posts:

- Incredibly, impossibly beautiful time lapse video
- Lenticular clouds over the Boulder foothills
- Superb time lapse: “My Soul”

CATEGORIZED UNDER: Astronomy, Pretty pictures
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