April 30, 2008 at 17:44 pm | Leave a Comment
Comes to a GoogleEarth Program Near You!
The ionosphere — it’s a layer of ionized gases at the top of Earth’s atmosphere, and something we don’t think about too much unless it gets all muddled up by disturbances from the Sun. When that happens, we see auroral displays and also can experience periodic outages in radio communications, GPS reception, and power systems.
Ham radio operators use the ionosphere to “propagate” radio signals around the world, and as it turns out, so do aircraft that fly over the poles (and out of reach of communications satellites). There are a great many scientists around the world who study the ionosphere, including the people I work with at MIT Haystack Observatory.
Now, through the auspices of the Communication Alert and Prediction System folks, you can explore a 4-D model (visualization) of the ionosphere using GoogleEarth. Today, at the Space Weather Workshop in Boulder, Colo., NASA-funded researchers released to the general public a new “4D” live model of Earth’s ionosphere. Without leaving home, anyone can fly through the dynamic layer of ionized gases that encircles Earth at the edge of space itself. All that’s required is a connection to the Internet. Airline flight controllers, for example, can use this tool to plan long-distance business flights over the poles, saving money and time (and boosting safety) for flyers.
In a kind of cool “blast from the past” I note that an old friend and graduate school officemate of mine, Lika Guhathakurta (a NASA solar physicist) was the one doing the announcing in Boulder. So, go read about the ionosphere at the links above, and then check out the latest ionospheric data and see what’s fascinating Lika and the other astronomers who make it their business to study the ionosphere!
April 30, 2008 at 12:58 pm | Leave a Comment
It Turns Out They Do… All Over the Place
Back before astronomers had high-resolution cameras and spectrographs and orbiting spacecraft to look at the distant universe, interacting galaxies were just plain weird. They didn’t fit into the standard scheme of galaxies as set out by the venerable giant of astronomy, Edwin Hubble. Every astronomer worth his (and sometimes a few “her”) salt memorized the Hubble tuning fork diagram and tried to fit every galaxy observed somewhere in this hierarchy.
Trouble is, not all galaxies “played the game.” Some of them looked downright pathological, twisted up, or misshapen or something. But the problem was that until we could look at these galactic weirdos with good optics and high-resolution spectrographs, astronomers couldn’t really tell what was going on with many of them.
That’s why the monumental set of galaxies that Hubble Space Telescope and other high-resolution ground-based observatories have observed over the years is such a great achievement. For the first time, astronomers can see what’s happening. And, they’re finding galaxy interactions (collisions, if you will) all over the place. The fact that we’re seeing them nearly everywhere we point a telescope to tells us that collisions aren’t just oddball occurrences in the universe. They’re part of an evolutionary process that shapes galaxies and triggers star formation in the process.
Our own Milky Way is actually cannibalizing smaller galaxies as you read this. The Sloan Digital Sky Survey is tracing out the streams of stars that are pouring into our galaxy as these smaller galaxies interact with the Milky Way. Here’s what it looks like from our vantage point inside the Milky Way.
Galaxy interaction is a hot topic in astronomy these days as the folks researching these cosmically titanic events dig into the details. Stay tuned!
April 29, 2008 at 16:21 pm | Leave a Comment
Because It Takes You Places You’ll Never Go
Star-forming region NGC 3582
T. A. Rector (U. Alaska), T. Abbott, NOAO, AURA, NSF
Courtesy Astronomy Picture of the Day
A few weeks ago I was flying to a meeting across the country. I always bring along some reading material, since it doesn’t take me more than 10 minutes to get through the airline magazine. I sat there reading a copy of Physics Today,. After I put it down to rest my eyes a bit, the person sitting next to me looked it over and smiled. “I always hated physics,” was the comment. I patted the magazine and said, “I flunked it once. But I went back and took it again because physics describes how things work. And that fascinates me.”
We kept talking for a while, and eventually my seatmate asked what I do for a living. I never quite know what to say because I’ve done a great many things. I’m a writer, for sure. But, to get here, I had to go a lot of other places. I’ve been in astronomy research, worked at a newspaper (where I agitated to write more stuff about astronomy), edited a magazine (about astronomy), written books (about astronomy), write scripts (about astronomy) and… well, you get the picture. So, I said that I write about astronomy. That led to another question, “Why do that? Are you into it?”
Now, these questions aren’t asked maliciously–the person really does want to know. So, we got into a discussion about astronomy, how I first got started, and how I work to spread the word about astronomy these days. And, I got in a few points about how astronomy is a great science for everybody to appreciate. My seatmate mentioned going out stargazing with family members as a child. And talked a little about going to the planetarium for school visits. And then said, “What I like about astronomy are the pictures. I don’t always understand them, but I like them.”
I asked why, and after pondering a while, my airplane friend said, “Because they take me places I could never go.”
April 25, 2008 at 10:36 am | Leave a Comment
Hubble Sees It
Hubble Space Telescope has been peering out at galaxies (and all kinds of other objects in the cosmos) since 1990. Over the years it has captured many views of galaxies interacting. By interacting, I mean that they come together, they collide, they mingle stars and clouds of gas and dust, and then in the aftermath, new stars are formed. The view from a distance is breathtaking. Like this one. The combined galaxy interaction is named NGC 5331, and they lie about 450 million light-years away from us in the direction of the constellation Virgo.
The collision of a pair (or more) of galaxies begins long before they look like they’re actually touching. The gravitational influence of both galaxies begins to pull shreds of galaxy parts (gas, dust, stars). It also starts to distort the shape of the galaxies doing the interacting. If you look closely at this pair you’ll see some part of the lower galaxy is being pulled toward the “upper” galaxy. There are also little blue clouds out to either side of the galaxy. Most likely those are star-forming regions, so-called “starburst” knots that are ignited during galaxy interactions. (There are also other galaxies in the picture — see if you can spot them all.) As things proceed, you start to see definite “shredding” effects as the shockwaves of collision distort the galaxies.
To celebrate the 18th anniversary of Hubble’s launch (gad, has it been 18 years already?), the Space Telescope Science Institute and the Hubble ESA folks have released an image collection of 59 galaxy interactions. Here’s another one — the interacting galaxy pair that makes up Arp 148. This one shows the pair well after the collision (interaction) began. The blue “ring-shaped” object is a collection of matter ejected by the shockwave generated during the collision. It’s blue because the shock also touched off a burst of star formation. Those are hot, young blue stars there, just beginning their lives in the chaos of a galaxy collision.
You can see the other 57 galaxy interactions here. Be prepared for quite a fascinating tour! It’s amazing what can happen when some of the biggest structures in the universe do a little cosmic dance with each other!
April 24, 2008 at 22:14 pm | Leave a Comment
I Hear it Often
The other day on the way home from San Francisco, I was waiting for a plane in Chicago and got to talking to a woman who was on the same flight with me. We swapped information about what we each did for a living, and eventually she came around to what I think of as The Question: “Why do you like astronomy?”
It’s a variant on a question that one of my professors asked me when I was in graduate school and told her that I wanted to take a minor in telecommunications engineering. She looked me right in the eye and, with a dismissive wave of her hand, asked: “Why do you want to take that geeky shit?”
The answer in both cases is the same: because it fascinates me. It’s science and it presents me with ways of knowing things about the universe (in the case of astronomy) and things about the technical aspects of communication (in the case of telecom) that I just don’t get in my every day reading. Considering that I was majoring in science writing in grad school, I’m kind of surprised that my former prof asked me that. But then again, she was a political writer, and there was (and is) no way I’d want to write about politics, so I guess it all evens out. I couldn’t imagine being fascinated with writing about the ins and outs of political campaigns, but it meant something to her much the same way that science does to me.
So, science is a way of knowing what’s happening in the cosmos. It gives us rules (like the laws of physics, for example) that can be applied to help us understand why a planet spins on its axis, or the wind blows or the ocean currents flow the way they do, or any of a billion, billion other topics that comprise scientific understanding. It’s totally cool to be standing on the edge of knowledge like that, open to the possibility that a new piece of data will come in that explains some aspect of a supernova explosion that we didn’t know about before. Or, that helps us understand just how it was that amino acids arranged themselves in a configuration that helped life arise on our planet.
The other day, I told my airport companion some of that and she looked a bit blank at first. Sometimes that happens, and the next thing out of their mouths is a statement like: “Oh, I never was any good at science.” But, this one surprised me. She started asking other questions, stuff that I suspect she’d never had a chance to ask before because…. well, probably because (given her lifestyle and experiences) she’d never met a scientist before or a science writer who could explain things to her. And she asked good questions, which is the essence of being a good scientist (and journalist, for that matter). Those kinds of conversations are fun, and they teach me as much about what interests people about science as I (hopefully) teach them about astronomy.
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Image of Horsehead Nebula: T.A.Rector (NOAO/AURA/NSF) and Hubble Heritage Team (STScI/AURA/NASA)
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