Tag: Perseids

A little sunset CARMA

By Phil Plait | September 4, 2012 11:00 am

Jeff Frost is a photographer who wanders the world taking pictures of interesting things – abandoned buildings are a favorite of his.

He was in Yosemite, near Bristlecone Pine, in mid-August to try to get some pictures of the Perseid meteors. He got rained out, unfortunately, but apparently he got some good karma at sunset… or rather, great CARMA:

[Click to embiggen.]

CARMA is the Combined Array for Research in Millimeter-wave Astronomy, a collection of dishes that observes objects in the Universe that emit light at millimeter wavelengths – past the infrared region of the electromagnetic spectrum, but not as far as radio waves. Cold objects glow with this kind of light: dust, molecules between the stars, comets, and the leftover radiation from the Big Bang itself.

Jeff got to the array as the Sun was setting, and took this beautiful shot. What’s neat is that they were probably active at that time; millimeter waves go right through our air and aren’t scattered like visible light – and the Sun is pretty dark at those wavelengths – so CARMA can watch the sky day and night. Even through clouds!

In grad school I took a class in radio astronomy, which is turns out is very different than ultraviolet/optical/infrared astronomy. I did OK in the class, but my heart lies in the near-visible spectrum and higher energies. I’ll leave the weird radio stuff to people like NoisyAstronomer.

And I’ll leave you with this lovely time lapse video Jeff made called Flawed Symmetry of Prediction:

Image credit: Jeff Frost, used by permission

CATEGORIZED UNDER: Astronomy, Pretty pictures

Perseids over Denver, from 14,000 feet

By Phil Plait | August 15, 2012 7:00 am

I saw quite a few photos of the recent Perseids meteor shower, but one of them is a clear winner: this ethereal, beautiful shot by astrophotographer Thomas O’Brien:

[Click to enmeteoroidenate.]

Isn’t that stunning? He took it at Mt. Evans in Colorado, at an elevation of 14,000 feet. He was looking east, over Denver, and you can see the waning crescent Moon rising just over the city. Breathtaking.

What’s funny, too, is that the first picture I saw by him was the small one inset here (click it to embiggen) which is also beautiful. I asked him if I could run it on the blog, and he said yes… and then I saw the Moonrise picture above and quickly changed my mind on which one to run first!

Thomas has a lot of gorgeous night sky shots on his website, and he sells prints of all of them. He’s got some seriously great stuff there.

And if you missed the meteors, don’t fret: the Leonids and Geminids are coming up in the next few months, and they’re really good, too. I’ll have more on them as their time approaches.

Image credit: Thomas O’Brien, used by permission.

CATEGORIZED UNDER: Astronomy, Pretty pictures

Perseid meteors peak over the next few nights

By Phil Plait | August 11, 2012 10:47 am

The annual Perseid meteor shower peaks over the next night or two, so this is the best time to go out and look. I have a guide on how to observe the shower and a couple of links, too, but first indulge me a moment to talk about meteor showers.

The Earth orbits the Sun, as do comets. Comets are lumpy collections of gravel and dust held together in a matrix of frozen ice (usually water and/or carbon dioxide). As they get near the Sun, the ice turns into a gas, freeing the dust and gravel. This material follows in the same path of the comet like dirt flying off a dump truck on a highway. Over time – millennia – it spreads out into space.

The Earth plows into this stuff as it goes around the Sun. These tiny bits of cosmic jetsam burn up as they ram into our atmosphere at speeds of up to 100 kilometers per second, and we call them meteors.

Quick tip: a meteoroid is the solid bit of rock or whatever that travels through space. As it burns up in our air we call it a meteor. If it hits the ground, it’s called a meteorite. Now you can sound pretentious and correct people at cocktail parties!

The Earth is always being bombarded by meteors; about 100 tons per day burn up in the atmosphere. But that number goes up when we pass through the stream of matter that’s come off a comet – think of it as driving down a road and hitting the occasional insect. Then you pass near a creek and suddenly you slam into a swarm of bugs.

So yeah, meteor showers are the equivalent of that. But much prettier and less disgusting.

Every August the Earth passes through the debris from the comet Swift-Tuttle, forming the Perseids meteor shower.

[The best place to observe the shower is apparently in Sarasota, Florida. Yes, this is a real picture; I took it myself.]

They’re called the Perseids because they appear to come from the sky in the constellation of Perseus. It’s a bit like when you drive through a tunnel and all the lights on the sides appear to be moving away from a point ahead of you. It’s perspective, an illusion of sorts. In this case, the orbits of the Earth and the meteoroids add together to make the meteors appear to shoot away from the part of the sky where Perseus is. Other showers do this too, but from different parts of the sky, and the showers are named after their constellation. Thus, the Leonids, the Orionids, the Taurids, and so on. The Perseids are one of the best of the year, with about 50 – 60 meteors per hour visible (so on average one per minute at the peak). You may see fewer than that, but sometimes there are mini-peaks where the number goes up. It’s worth going out for an hour or two to see them!

So here’s a very quick rundown of what you need to observe the shower (Universe Today has a good, short guide as well):

Read More

CATEGORIZED UNDER: Astronomy, Cool stuff, Pretty pictures

Top 16 Pictures from Space 2011

By Phil Plait | December 6, 2011 5:57 am

Listen in on the Perseid meteor shower

By Phil Plait | August 11, 2011 9:34 am

The Moon is putting a big wet blanket on this year’s Perseid meteor shower, making it hard to see them.

But that’s OK: if you can’t see them, why not listen to them?

Sounds weird, but thanks to SpaceWeatherRadio, now you can! 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! Here’s an example of a Geminid meteor; it sounds like it could’ve been pulled right off the soundtrack for "Forbidden Planet". There’s also more info on how this works on the NASA science page.

If you want to listen live, here you go. I had it going for a while and heard several faint but distinct dying "Eeeeeeeoooooooo" sounds from meteors within a few minutes (as well as other sharper sounds I’m not sure I can identify, which makes the whole thing even cooler). The best time to listen for Perseids is after midnight Texas (Central) time, but if you leave it running you’re bound to hear a few of those creepy sounds coming from your speakers.

I’ll note that other sounds can be made from radio waves in this fashion. You can listen to Saturn, hear what the Phoenix Mars lander sounded like on its way down to the surface of the Red Planet, and listen to very odd and creepy sounds of the aurorae.

The Universe is talking to us all the time, you know. We just have to have the right ears — and the brains between them — to hear what it’s saying.

Tip o’ the radar dish to BlackProjects on Twitter.

CATEGORIZED UNDER: Astronomy, Cool stuff
MORE ABOUT: echo, Perseids, radar

The Perseids are coming… but so's the Moon

By Phil Plait | August 8, 2011 12:00 pm

Every year around August 12/13th, the Perseid meteor shower peaks. It’s a fairly reliable shower that generates 60 or more meteors per hour. Unfortunately, this year the Moon is full at that time, washing out the sky and any fainter shooting stars.

Still, it may be worth a shot for you. Meteor Showers Online has some info on the event, and I wrote a post a while back on how to watch meteor showers that still works.

Last year, photographer Siddhartha Saha shot a nice time lapse video of the Perseids:

At 10 seconds in, one of the meteors leaves what’s called a persistent train; a streak of vaporized material that sits in the upper atmosphere and glows. You can see the winds whipping it into a twisted shape. I’ve never seen this happen myself, but one day…

If you miss the Perseids, don’t fret: there are plenty of others this year. The Leonids and Geminids are also good performers. And any dark night will generally have a few to spot, just random pieces of fluff that hit us all the time. It adds up to about 100 tons of material a day burning up in our atmosphere, so why not go outside and see if you can spot any?

Related posts:

12 things you need to know to watch the Perseid meteors
Pursuing Perseids
Mesmerizing Perseid time lapse video
New meteor shower points to a future close encounter

em>Tip o’ the Whipple Shield to BABloggee Anu R for the link to the video.

MORE ABOUT: meteor shower, Perseids

Mesmerizing Perseid timelapse video

By Phil Plait | August 20, 2010 11:00 am

I missed the Perseids last week — a combination of bad weather and having to get up early to go to SETIcon the next day — but I, and now you, can get a good feel for them via this lovely timelapse video taken by photographer Henry Jun Wah Lee:

Joshua Tree Under the Milky Way from Henry Jun Wah Lee.

I’m not sure how many of those streaks are Perseids, how many are random meteors (typically from any given location you see a handful of sporadic meteors per hour) and how many are airplanes. Still, it’s pretty.

The large lumpy cloud you see in this video is actually the Milky Way. Read More

CATEGORIZED UNDER: Astronomy, Cool stuff

Pursue the Perseids tonight!

By Phil Plait | August 12, 2010 11:00 am

netherlands_meteorThe next couple of nights bring us one of the best meteor showers of the year: the Perseids. It peaks around mid-August — this year the peak is tonight, Thursday August 12 — when the Earth plows through the debris from the comet Swift-Tuttle. This year should be pretty good, as the Moon sets early, and won’t interfere with seeing fainter meteors.

If you don’t think the Perseids will be cool, then watch this:

Love it! Want more info?

Back in 2007 I wrote up a brief guide on how to observe the Perseids, and it’s still pretty much apropos of the shower this year (just replace "Sunday" with whatever day you’re observing). The most important things: the later you go out, the better since the shower really peaks after midnight; you need a clear view of as much of the sky as possible; and you don’t need any equipment, but I recommend a lounge chair to lie back on.

Other sites are covering this as well, of course:

– Wanna chat about the meteors? NASA is hosting a live chat Thursday night/Friday morning (Aug 12/13)!
Universe Today
Tom’s Astronomy Blog

So get out there and enjoy the shower!

MORE ABOUT: meteor shower, Perseids

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