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Anything and everything about science, especially astronomy and the cosmos.

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Visit my web site at
TheSpaceWriter.com
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C.C. Petersen

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ABOUT ME

I'm a science writer and editor. I work with clients in the observatory and planetarium community, as well as my own book, web, planetarium, and other projects.

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1.31.2008



Craters!

\


I just spent about an hour analyzing craters on Mars. You can, too. Don't believe me? Check out the Clickworkers Site and learn how to recognize craters and their shapes and ages. While the work for this site was originally done in 2000-2001, and the study for which it was created is over, the pages are a great way to learn how to analyze Martian surface features in much the same way planetary scientists (and their grad students) do. It's a lesson in terrain recognition that anybody can do—and in my ever-lasting chase to convince folks that science is for everybody, this is one of those tasks that really brings it home! So, go give it a try, you future Martians, you!

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posted by CCP on 1/31/2008 12:23:00 AM | * |

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1.29.2008



It's Elemental, Dear Watson



In the last entry, I referred to a star that astronomers studied to understand its chemical makeup in an effort to figure out where it came from. That raised a question about how astronomers figure out the chemical makeup of a star.

They use a technique called spectroscopy. That's really a $25.00 word that means "breaking the light up into its wavelengths" and then comparing the data to the spectral fingerprints of known chemical elements. This is something that chemistry folks (who study the elements in the universe) do all the time, and a technique that let astronomers look at the radiation emitted from an object in space in new ways. It's fair to say that when astronomers began using spectroscopy to study stars and galaxies, the science of astrophysics took a huge leap forward.

Astronomers use specialized instruments called spectrographs, which were first used by chemistry researchers to study the spectral fingerprints of elements in the lab. (Read more about them here). Astronomers employ spectrographs to break up the light from stars, galaxies, planets, nebulae, etc. into its component wavelengths. The data from these instruments is then plotted, which lets the researchers analyze the chemical signatures in the light and compare them to the signatures of known elements.

The "prism" view of a spectrum of a star with hydrogen in its atmosphere might look something like the images below. The top image shows what it looks like when hydrogen absorbs light as it is emitted from an object. This means that hydrogen exists in or near the object. The bottom image shows what it looks like if hydrogen is emitting radiation (while it is heated). Each chemical element has a unique absorption fingerprint.



Hydrogen absorption spectrum, courtesy www.solarobserving.com.


Each element has a typical "absorption" pattern that shows up in the spectrum of a star where the element exists. An object in space can also have an emission spectrum, which tells us that some element is being heated and glowing brightly. There's a rather nice tutorial about spectra here if you're interested in learning more about them.

So, the short answer to the query about how the astronomers figured out the chemical makeup of the star HE 0437-5439 is, they studied the light it radiates and compared what they found to the known chemical signatures of elements, particularly metals. They then compared THAT information to spectral studies of regions in the LMC. From that, they can draw a pretty good assumption that the star came from that region.

One other thing about spectra: you can also tell an object's velocity through space and the direction it's traveling, all using spectra. There's a gold mine of information locked away in the light and other wavelengths of radiation being emitted from objects in space. It's an amazing treasury that astronomers tap into every time they study an object through a spectroscope.)

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posted by CCP on 1/29/2008 08:32:00 PM | * |

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1.28.2008



Aliens from Other Galaxies



You know that town in Texas where the residents think they're seeing alien UFOs (which turned out to be Air Force jets)? Well, they haven't seen anything as alien as what the folks at the Carnegie Institution of Washington found when they did observations and analysis of a star called HE 0437-5439, a so-called "hypervelocity" star. It's speeding away from the Milky Way, but it wasn't born IN the Milky Way. So, astronomers studied its mass, age, and speed of the star, which is about nine times the mass of the Sun. It's moving into intergalactic space at about 2.6 million kilometers per hour. That's much too fast for it to have come from the Milky Way, but where DID it come from?

As it turns out, HE 0437-5439 was born in the Large Magellanic Cloud, a neighbor galaxy to the Milky Way. The Carnegie astronomers figured this out by looking at amounts of certain elements in the star. The "elemental abundances" they found point to a particular area in the Large Magellanic Cloud where similar amounts of the same elements exist. Hence the star more than likely formed in that region. So, what's it doing speeding away from the LMC and the Milky Way? Stars don't get up and flash out of their home galaxies just for the heck of it. They have to be kicked out by something.

The most likely scenario goes something like this: HE 0437-5439 formed as part of a binary system (a pair of stars orbiting a common center of gravity). As that pair of stars moved through space, they passed by a black hole that was about a thousand times the mass of the Sun. As we all know, black holes suck; that is, they have strong gravitational pulls. One star of the pair got pulled into the black hole, while the other got a gravitational kick that flung it out of the LMC. Now the surviving star (HE 0437-5439) is on its way to intergalatic space, leaving astronomers with an important clue that there's at least one black hole in the Large Magellanic Cloud. Now they just have to find it. (Note: for more information, read this press release.)

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posted by CCP on 1/28/2008 12:42:00 PM | * |

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1.25.2008



It's Not the Impact You Think It Is



You may have heard (or seen in the news) about an asteroid that's due to pass close to Earth on January 29 (next Tuesday). It's called 2007 TU24, it's about the size of the Sears Tower in Chicago, and it will flash past at a distance of about 537,000 kilometers. To put it in perspective, the Moon lies 383,180 kilometers away, so this thing isn't getting as close to us as the Moon is.

This is a rare chance for astronomers to image a near-Earth asteroid and use instruments such as the Arecibo radio telescope to accurately measure its size, spin rate, and orbital speed.

Stuff like this passes near our planet rather frequently; after all, space is full of debris left over from the formation of the solar system, and not all of it has been swept up by planets, moons, and ring systems. That's the beauty of having an evolving planetary system. Now that we have good instrumentation, we can study these pieces of debris and learn a variety of things: what they're made of; and from their orbital measurements, we can figure out the larger picture of orbital dynamics. And, of course, we can learn more about how to spot these things and determine if (and very, very rarely when) they might pose a threat to the planet.

Now, there are a few whack jobs out there who are using this upcoming event to draw attention to themselves by making outrageous claims. It's the usual huffing and puffing and uninformed bloviating about how NASA is hiding evidence that the rock is actually going to HIT Earth, yadda, yadda, yadda. And I have to wonder just how much physics these folks ever studied, or passed? And what part of "it's farther away from us than the Moon is" didn't they get?

I've calculated a few orbits in my time (and by the way, doing a general orbit calculation isn't rocket science—kids in high-school math and physics probably cut their teeth on these things in middle school these days) and I'm here to tell you it's not difficult. And what you learn tells you pretty quickly just how much chance there is an impact vs. a flyby.

Here's how it works. You observe an object and plot its position. Then you do it again. And again. Pretty soon you have a line that, after you've got enough positions, allows you to plot the entire orbit pretty quickly. Once you do that, you can see where the object is going to be as it moves along in its orbit.

You can understand roughly how this works by watching cars on a road. After a while, assuming that the cars are going the same direction, not turning off on other roads, and they're not whacking into each other, you will be able to "predict" that a car going a given speed down the road will be at Point B at a certain time, then Point C, and so on.

Now, the people at JPL whose job it is to calculate orbits have done a very refined job of plotting the orbit of 2007 TU24. And guess what? It's not going to hit us. Physics and orbital mechanics tell us this.

There's no hidden agenda. NASA isn't hiding anything. It's all in the physics and orbital mechanics. Even if NASA tried to suppress knowledge, the amateur astronomy community can often see these things and those folks can calculate orbits, too. It takes no esoteric knowledge, just the ability to apply the laws of orbital motion. And actually, if you can get hold of orbital elements (and they ARE freely available) YOU can plot an orbit. And you'll see that the thing is going to miss Earth by a long shot.

So, let's apply a little common sense here and use some science to understand these things. If somebody wants to believe hyperbole and self-serving claims of cover-ups and other malarkey, let's be clear that it's really about delusions of grandeur among those who are too lazy to do the math. And that's fine (although silly). People can think or believe what they wish. But, wishing doesn't make it so.

Uninformed ravings about coverups and plots and so on simply prove that the only impact we'll see on Tuesday is that of lazy thinking. Perhaps we can use that kind of impact as a lever for more effective science education in our schools and less foolishness.

For more information on this event and the orbital calculations, check out the Near-Earth Object Program page at NASA.

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posted by CCP on 1/25/2008 11:37:00 AM | * |

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1.22.2008



The Case of the Lobate Scarps
A Noir Look at Mercury's
Mysterious Surface Evolution





Mercury's horizon, as seen by the MESSENGER mission.


The name's Basin, Caloris Basin, and I'm a planetary science detective. Perhaps you've heard of me. Of all the planets in all the solar systems in the cosmos, I'm interested in Mercury. It's a classy place, with a great surface to boot.

So, until just a couple of days ago, things weren't going too well for me. I'd been stonewalled with a lack of knowledge about ALL of Mercury's surface. It was tough, and I was down to my last... well, let me tell you the whole story.

It was late on a Friday afternoon in mid-January. Business was slow. It had been for years, ever since the Cassini mission had launched, followed by New Horizons. Everybody's attention was turned toward the outer solar system, or near-Earth asteroids, or dwarf planets beyond Neptune.

And, it seems that ever since I'd cracked the case of the sulfuric plumes in the Venusian atmosphere, inner-solar-system detective work had just dried up. Pancake eruptions on Venus were so last-century. Even Martian dust storms weren't getting as much press as they used to. Oh, sure, the occasional asteroid-impact threat on Earth raised a little stir now and again, but in the main, it seemed like nobody cared about the inner planets any more. A pity.

I mean, there was Mercury, waiting to be explored again. Even though Mariner had given it a quick look back in the 1970s, its glory days weren't over. Not by a long shot! Sure, its surface would be at home on a black-and-white scene from a 1940s detective movie set (without the rain and fog, though). And sure, it's a bear to observe from Earth. But, Mercury's got as many mysteries as those outer planets, and it's a darned sight more rocky!

Still, all the hot researchers and their grants (and grad students) were out there at Saturn, and using Hubble and ground-based telescopes to poke around Pluto and the Kuiper Belt. They were flush with success, invoking cryovolcanism right and left to explain what they were finding! Yet, for my NSF grant money, there was a lot of good science to be done in the inner solar system. So, I resigned myself to having to wait for a while. I knew that soon I'd eventually have my day in (or actually near) the Sun.

Well, there wasn't much work waiting for me that day, so after feeding the boa constrictor that had been with me since my grad school days, I settled in with a six-pack of Red Bull and a stack of back issues of Icarus to wade through. I had just put my feet up on the desk and was reading "Fugitives from the Vesta Family" (Nesvorny, et al., 193, January 2008, p. 85-95) when I heard a knock on the door. It was the sound I'd programmed on my computer to let me know when a potential planetary science discovery was waiting to be investigated.

There it was: a GoogleNews alert about the MESSENGER spacecraft. It seems that it had finally gotten a look at a place that had intrigued me for years, ever since I first observed the planet Mercury at greatest eastern elongation back in grad school. I was so taken with the place that I'd gone on to study what little we know about this planet closest to the Sun.

And that's when I learned about the mysterious lobate scarps. For my money (at the time, low grad-student slave wages), those scarps (cliffs to you regular joes) were evidence. Of what, I wasn't sure. But was going to find out. Once I saw them in old Mariner Mercury images, they haunted me. I had to know more about how they turned Mercury into a wrinkly prune of a planet in the prime of its life. I asked the standard detective questions. How did they form? When? And how many were covered up by impact-event melt rock? These were key questions, not to a crime, but to the mystery of Mercury's surface evolution.

The knocking on the door sounded again, jerking me out of my former-grad-student reverie and back to the present. As the images scrolled up on the monitor, I knew that my waiting had finally ended. The Mercury MESSENGER mission was sending back a flood of images, and not just of regions I'd already studied. These were scenes of the "far side" of Mercury that we never see from Earth because of Mercury's complicated spin-orbit resonance with the Sun. And what scenes they were! I leapt out of the chair, scattering magazines and empty cans across the desk. My time had finally come—and from a planet that had kept my investigative instincts alive for years!




Sure, there were the usual craters (new AND old), but what caught my attention were the scarps. MORE scarps, including one huge wrinkle that appears to be one of the largest ever found on Mercury. In another scene, old lobate scarps seem to be cutting across craters. Classic evidence you'd see at any surface evolution scene. I could hardly contain myself. And it was ONLY the beginning of MESSENGER's data dump.

I quickly set to work making notes, studying each picture for evidence of the story of Mercury that had only begun to be told when I was first in grad school. I remembered those old lectures as if it was yesterday, and yet, even today, parts of the story are still a classic detective tale.

Mercury began like all the rocky planets, hot and molten. While the others basked in relative coolness out away from the Sun, Mercury stayed hot for quite a while. As it cooled, its surface was blasted with impacts, digging out those craters we see all over the place. The craters weren't the mystery though. We know how they happen, and that they continue to happen. No, the case of the lobate scarps were what piqued my attention.

These cliffs are huge and jagged. What could have caused them? For a long time, that was the central mystery. But, eventually, we figured out the answer: Mercury cooled. Then it shrank. The shrinkage compressed and wrinkled the rocky surface. Early Mercury might have been all wrinkles. We'll never know for sure, since those impacts came in and covered up some of the evidence. But, there's enough left to give us a pretty good general picture of Mercurian surface evolution.

Now, I don't pretend to know the whole cooling and bombardment history of Mercury. That's a mystery I'm still working on. And, to be fair, all the MESSENGER scientists are working on it, too. I'll We'll have to examine each picture and each region on Mercury to figure out which came first: the cracks or the craters. It's standard planetary science detective work. But, I'm up to it; as long as MESSENGER sends pictures, I'll be on the case, cracking the case of the mysterious lobate scarps of Mercury. And, now that we have pictures of Mercury's polar region, maybe I'll tackle a new challenge: the mystery of Mercury's purported polar ices.



Is there ice hidden on shadowed crater walls at Mercury's poles? Visit the MESSENGER web site for the latest details and images from the mission.


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posted by CCP on 1/22/2008 01:15:00 PM | * |

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1.21.2008



Mars Again... and Again



Mars Rover Spirit Looks Out Over a Low Plateau


Mark and I just announced the fulldome incarnation of our long-popular show MarsQuest—something that's been a long time coming. The show itself has had several incarnations, beginning in 1988 when we created a show about Mars called "The Mars Show" and it was basically a slide show with a soundtrack. (Why that title? We could never think of a better one, so it kept that name for quite a while.)

In 1996, we got together with a group of people at the Space Science Institute in Boulder, Colorado, to talk with them about a traveling exhibition they were creating called MarsQuest. They wanted a planetarium show, and by golly, here we were with a planetarium show that we wanted to update. After a few meetings, we had a deal, and the rest, as they say, is history. The MarsQuest exhibition has finished its run around the country and is retired to a museum in Florida. But, MarsQuest the planetarium fulldome show is still very much alive and kicking, bringing info about the Red Planet to all and sundry.

It seems that I write about Mars every few years, and people often ask why. It's simple: I've always been taken with the Red Planet. It all goes back to a game we used to play when I was a kid, about exploring Mars. And that's part of it. As I got older, I read more about the planet, especially when in 1976 we actually landed a spacecraft there.

So, it was only natural that I'd eventually end up writing a documentary script about it. And revisiting it as more spacecraft send back more images and data about this planet. Not only did the game from my childhood spurred MarsQuest, and a scene in SkyQuest, a show we did for the National Air and Space Museum's planetarium. So the game I played keeps coming back in one form or another.

And it continues. As more Mars images and data come in, I continue to work on other Mars-related presentations. For me, this dry and dusty desert planet is also one of the most tantalizing places in the solar system, and if I were of the right generation, a place I could have once considered exploring in first person.

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posted by CCP on 1/21/2008 07:56:00 PM | * |

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1.18.2008



A Year of Astronomy






A hundred countries (and counting) have signed on to participate in the International Year of Astronomy, which runs throughout calendar year 2009. The IYA planners envision the year as a time when people take renewed interest in astronomy and science, from school children to members of the general public and the astronomy community (both professional and amateur).

On their web page the International Astronomical Union, which is spearheading the organization of IYA 2009, states:

The vision of the International Year of Astronomy (IYA2009) is to help the citizens of the world rediscover their place in the Universe through the day- and night time sky, and thereby engage a personal sense of wonder and discovery. All humans should realize the impact of astronomy and basic sciences on our daily lives, and understand better how scientific knowledge can contribute to a more equitable and peaceful society.

Now, we're a planet full of people, all with different languages, philosophies, levels of income, education, science interest, and political backgrounds. How can astronomy be something we can all appreciate? It's pretty simple really: we all have access to the sky. There isn't anywhere on Earth where you can't look up and see the sky, day or night. Granted some places have hazy, light-polluted skies. But, even in the worst places, you can see a few stars at night or the Sun, or the Moon. Astronomy is universal.

And that's the beauty of International Year of Astronomy. Anybody can do something with it, as long as it's related to the "Cornerstone Projects" that the IAU and IYA planners have developed. What are those projects?


  • 100 Hours of Astronomy
  • The Galileoscope
  • The Cosmic Diary
  • The Portal to the Universe
  • She is an Astronomer
  • Dark Skies Awareness
  • Astro&World Heritage
  • Galileo Teacher Training Program
  • Universe Awareness
  • From Earth to the Universe
  • Developing Astronomy Globally

You can read more about these projects the IYA home page linked above. I'm particularly interested in the Galileo scope, the Portal to the Universe, and the She is an Astronomer projects. Check out the pages and see if there isn't a project that excites you to participate, in whatever way you can.

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posted by CCP on 1/18/2008 10:16:00 PM | * |

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1.17.2008



Astronomy for Everybody






Noreen Grice is one of the most amazing individuals I know. She works at the Boston Museum of Science and has single-handedly brought astronomy to people who can't see the stars. Noreen took the unheard-of idea of teaching visual astronomy to the blind by using Braille books. Her first one was Touch the Stars. That one has been followed by Touch the Universe and Touch the Sun.

Now, her latest book, Touch the Invisible Universe is coming out, according to a press release that is showing up at various NASA-funded sites. It is being distributed by NASA to schools for the blind, and various libraries where it will be a resource for visually impaired people.

When it comes to ultraviolet, x-ray, gamma-ray, radio, and infrared radiation, we're all blind to the universe in those wavelengths. So, I think it's pretty cool that Noreen has taken a subject within astronomy that gives ALL of us an insight to things we can't otherwise see (wavelengths beyond visible (optical) light), and explains it all in a book that uses Braille, large print, and tactile "graphics" of astronomical objects, for those who cannot see at all. Astronomy is for everybody, and Noreen's new book brings that lesson home in an unforgettable way.

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posted by CCP on 1/17/2008 12:34:00 PM | * |

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1.15.2008



Black Holes

Not Just for Science Fiction Anymore



I've always been a sucker for mysterious things in outer space. No, not little green beings or monsters from Cryzalix IV or alien face-things on other planets that turn out to be eroded mesas. I'm talking about the real deal: strange things that really do exist, but when scientists first think about them, or observe them, they kind of scratch their heads and go "huh?" Black holes fit in that category. And, you know what? A LOT of people are really curious about black holes. If you're a planetarium lecturer or a scientist who does outreach, or a teacher who finds time to fit in some astronomy between all those other unfunded educational mandates you have to follow, you already know this. Black holes are just about the first thing anybody asks about as soon as the topic of astronomy comes up.

No, really. It's true. (Well, sometimes they ask about astronaut love triangles, but I don't want to go there and neither do you...)

Anyway, I wish I had US$5 (or 5 Euros, I'm not picky) for every time I've been asked about black holes while standing in a line at the store, or sitting on an airplane talking with somebody, or answering an email from somebody who's read my site. Black holes are just that popular. Yet, I remember a time when they were pretty much flying beneath the public's radar.

Back when I was a kid a few decades ago, black holes were taken seriously more as theoretical constructs—objects that mathematical and scientific models said could exist, but nobody had actually seen in real life. There are a lot of science fiction stories about using wormholes to ride around the universe in; those are based on some theoretical constructs called Einstein-Rosen Bridges.

Pretty speculative, but interesting to think about. And, certainly TV and movie science fiction stories often depend on spectacular special-effects wormholes to keep people moving. But, right now those remain on the dreamers' drawing boards while astronomers study the real-life black holes that are turning up everywhere.

So, black holes hide in a lot of places. Astronomers have known for a while that they exist in the hearts of many galaxies, and they're also the powerful engines under the hoods of quasars. Back when I was a teenager, Quasars were TV sets. Now they're better known as the bright, distant and extremely active core regions of galaxies. Radiation pours out of these things in many wavelengths of light, including x-rays and radio waves.

Last week at the American Astronomical Society, we heard a LOT about black holes. I was especially intrigued with the story out of Vanderbilt University that there could be hundreds of rogue black holes roaming around our own galaxy. They got the galactic heave-ho from the globular clusters where they formed.

But, for my money, the most interesting black holes are the ones that lurk in the hearts of galaxies like our own. You can't see the one making its nest in the core of the Milky Way because it's hidden behind clouds of gas and dust. And, well, you really can't see a black hole anyway. What you DO see is the chaos that is created when a lot of matter swirls into the black hole. In addition to the stars, gas, dust, and other stuff that is getting sucked into the black hole, powerful and twisted magnetic fields are funneling superheated plasmas out to space, in the form of jets.

All this activity gives off those x-rays and radio waves I just mentioned. And, the heat in the region also warms up clouds of gas and dust, which glow in infrared wavelengths. So, looking for black holes is a multi-wavelength (except for visible light) proposition, particularly for the Milky Way's black hole.

If you want to read more about the black hole in the Milky Way's core, I recommend a very cool book called The Black Hole at the Center of our Galaxy by astronomer Fulvio Melia. I reviewed it a while back for Sky & Telescope Magazine, and I still remember what a great read it was. There's a lot we know about black holes, and they're not just for science fiction any more. They play roles in everything from the earliest galaxy formation to stellar evolution.

The latest installment of my little vodcast series about all things astronomical is also about black holes, specifically the one at the heart of the Milky Way. Check it out!





To see this video here, you need to tell your browser not to block active content, or you need to get the Flash player. RSS readers who can't access the video can download it here.


Creative Commons License

This work is licensed under a
Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 Unported License.

posted by CCP on 1/15/2008 10:34:00 PM | * |

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1.13.2008



A No-Go Asteroid Collision



Well, it looks like Mars isn't going to get smacked at the end of this month after all. Astronomers are now giving the asteroid 2007 WD5 a 0.0 percent chance of hitting the planet, based on updated orbital information for the wandering bit of solar system debris. The best guess puts the asteroid on a close fly-by, passing about 7 Mars radii from the surface.

Being the bloodthirsty lot we are, some of us at the AAS meeting last week were talking about how "cool" it would be if something DID smack into the surface of Mars, especially while we could watch it with orbiting spacecraft around Mars and the surface-bound rovers. I guess it's the planetary science equivalent of being a pyromaniac (and watching things blow up).


Planetary Bod Mods

Impacts, which we don't get to see happen very often, are one of the ways that solar system bodies are modified. Worlds can get smacked into, surfaces can be eroded by weather and other atmospheric processes (like rain and snow (and not just rain and snow made of water, mind you)), they can be paved over by volcanism, or they can be disturbed from below the surface (quakes and subsurface activity driven by internal heat).

Mars has been modified by all these processes over the billions of years it has existed. Take a good look at any picture of Mars, like the one below (taken by the Mars Global Surveyor on August 8, 2006), and you'll see impact craters, or canyons, or the remains of what look like dry riverbeds tracing their way across the plains.




Every one of those surface features has a story to tell about some aspect of Mars history, and we're just now decoding what they have to say. So, while I'd have loved to have seen the effect of an asteroid smackdown on Mars, I'm not too upset that it's missing the planet. There's plenty of "cool" stuff to study already!

posted by CCP on 1/13/2008 09:59:00 PM | * |

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1.11.2008



Cosmic... and Highly Fascinating



Astronomy news can invoke images of weirdness that most people don't think about in their everyday lives. Colliding gas clouds, superdense neutron stars that might be giant quark balls—there's no end to the strangeness and wonderfulness of the cosmos.

About those colliding gas clouds... it seems there's a huge mass of hydrogen gas headed toward the Milky Way Galaxy. I heard about it at a paper session on Thursday and it might make the news if some enterprising reporter picks it up and runs with it. Of course, editors being what they are, if this action isn't related to the election silly-season stories, Britney Spears's latest antics, Nicole Kidman's baby bump, or a sports scandal, the story will probably end up at the back of the C section of the newspaper, right before the marriage column. But I digress...

When this gas hits, in less than 40 million years, it'll set off a huge array of stellar fireworks in the region where it collides.

You can breathe a sigh of relief, since this will happen in very distant future, and it won't hit us directly. This cloud of gas, called "Smith's Cloud" will hit farther out in the galaxy than the region where we bob along on the galactic currents, and about 90 degrees ahead of us as the galaxy spins. Still, on the odd chance that you're still around when this happens, look for certain parts of the sky to light up and blaze as the collisions trigger bouts of star formation. Read more about it here.

Speaking of violence in galaxies, the Chandra X-Ray Observatory is taking a look at black holes in galaxy cores, and providing evidence that many supermassive black holes embedded in these hidden regions are spinning extremely rapidly. Now, if you were hanging around the accretion disks that are circling the drain around these black holes, you'd notice that all the stuff in the disk (including, presumably, you) would be getting flung around in orbit around the black hole at close to the speed of light.

And what about that quark ball I mentioned? This morning we had a press conference about a pulsar in a globular cluster. Using Arecibo to measure the timing of the pulsar's signal, astronomers have been able to determine a pretty good estimate of the mass of the neutron star at the heart of the pulsar. Now, neutron stars are pretty darned massive; they are basically a ball of matter the mass of Earth squeezed into a region of space about 7-14 kilometers wide. Nobody knows what matter is like after it's been compressed this tightly, but one very educated guess is that it could be a ball of quarks (subatomic particles) glued together. Particle physicists can't even model this state of matter in an accelerator!

Astronomers using telescopes on Mauna Kea in Hawai'i have found a rare quartet of stars that orbit each other within a region smaller than Jupiter's orbit around the Sun. Could they have been born in this close proximity? Or, did something else happen to force them to snuggle up together? Check it out.

Planets haven't been left out of the excitement at this meeting. An astronomer at the University of Texas at Austin has made the first ground-based discovery of an extra-solar planet's atmosphere, using the Hobby-Eberly Telescope at McDonald Observatory.

Finally, there's a new radio series on NPR called "Cosmic Radio." Produced by the National Radio Astronomy Observatory, the series is bringing the history and science of radio astronomy to listeners, in 2.5-minute bite-size lengths. Check out the program's Web Site for more details.

It's been a productive and exciting week here in Austin. This "astronomy seminar" is about to come to a close, but for all of us interested in the ongoing research that brings us closer to understanding the cosmos, the story continues...

posted by CCP on 1/11/2008 11:41:00 AM | * |

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1.10.2008



The Cosmic Continuation



Today's the next-to-last full day of the AAS meeting, and the news just keeps rollin' out! Here are the cosmic stories making the press release headlines today:



I just got back from an overview of the state of the art in radio astronomy, preceded by a code-writing workshop using GoogleSky. The Google folks are here in force, helping astronomers make use of Google tools on their web pages and in the classroom. Now... I'm headed down to the exhibit hall! I'll have more thoughts and stories later on.

posted by CCP on 1/10/2008 03:33:00 PM | * |

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1.09.2008




Visualizing the Early Universe: My Cosmic Aha Moment



Coming to AAS is, for me, a week-long astronomy seminar. I suspect it is the same way for many attendees, not the least of which because we get to see and hear about results that are very interesting. Now, they may not always be our areas of expertise, but taken together, give us a larger view of the cosmos and its processes.

I always come away with an "aha" moment or two at each meeting. I've got several candidates for such moments that will probably translate into a writing project in the next few months, especially in the planetarium and vodcast realms. Let me share one of them with you here.

About twenty years ago, when I first went back to school to study astronomy, I was talking with my advisor (and future co-author) Jack Brandt about the big unanswered questions in astronomy and astrophysics. Of the many we discussed, one resonated with me: how did the first galaxies form? At the time there was not a lot known (or modeled) about dark matter and how it might constrain the early universe; indeed we were less than a year away from the launch of the Cosmic Background Explorer (COBE), which provided us the first good look at the cosmic microwave background.

There wasn't a good answer at that time about how we got from the first stars to the first galaxies. I remember Jack saying that maybe in 10 or 15 years we'd have better answers, especially after COBE, and maybe later instruments on HST would give us a look at the early universe.

And so, I waited. And every once in a while I asked that question again. And, the answers I got were getting more detailed about the early universe. But, there wasn't the answer I was looking for.

Well.

Today, 20 years later, I finally got an answer to my question. And, while we (meaning astrophysicists) still don't have the complete picture (all I's dotted and T's crossed), the basic picture is that some 300 million years after the Big Bang, the first stars formed, and they were massive. They were all hydrogen and grew to huge masses. And, high-mass stars live fast lives—dashing themselves to cosmic pieces as supernovae. And those supernovae seeded the cosmos with the elements for second-generation stars (the ones that have more than just hydrogen, but heavier elements and metals). Gravitational condensation and violent activity soon acted to constrain the early universe, going through whole collections of these first stars (called Population III stars). Eventually the first galaxies formed out of this violent chain of activity.

Now, parts of this theory are not new today, but what IS new and what gave me the "aha" I was waiting for, was this: visualizing the early universe with the first stars doing their thing is not an easy thing unless you have a ton of computing power. But, with a supercomputer, you can make a good start. And that's just what Dr. Volker Bromm and colleagues at the University of Texas-Austin have done. Today, they showed us the work they've been doing to probe the earliest epochs of star and galaxy formation. They used the Lonestar supercomputer to create visualizations of the action at the birth of the galaxies.nd, it was while watching those animations that I finally got my "aha"—a visceral understanding of what it might well have looked like 'way back then. The animations are here and comprise a short peek at what was, at the time I first asked my question, a time in the universe that was really not well explained at all. Today's explanation takes us a long ways toward understanding that epoch. How long before we can completely and accurately describe it? Soon, I hope. And these simulations are going to pave the way.

The image below is a still from that time, when large stars were blowing their mass into space, affecting the early universe, and setting it to the road of galaxy formation (the rise of structure in the universe). It is amazing to me, and very satisfying, to finally get an answer I can "grok" about something that has fascinated me for 20 years.



Hydrogen density interaction with high-energy, ionizing photons during the formation and decay of eight stars. Visualization by Paul Navratil, TACC.


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posted by CCP on 1/09/2008 11:31:00 PM | * |

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More Peering at the Cosmos



The Center of Centaurus A and Its Embedded Black Hole, as seen by Chandra X-Ray Observatory


Day two of the AAS meeting is just as frenetic as day one. There are hundreds of talks and papers being given about every aspect of astronomy you can think of— and then some! In addition, there are dozens of exhibit booths featuring astronomy missions, telescopes, contractors, NASA institutes, observatories and publishers.

I made it about halfway through the exhibits hall on Monday; my mean free path went to nearly zero, what with stopping to talk to various and sundry colleagues and friends. I did manage to spend some time talking with the folks at the Thirty Meter Telescope (TMT), a project I worked with briefly a few years back. Also visited with friends at Gemini Observatory, Konica Minolta's Planetarium division, and Cambridge Press. We'll see how far I get the next couple of days.

We're hitting our stride with news stories today—some rather breathless headlines about some breathtaking research. Two very fascinating results we heard about today were papers given on black holes. First, the existence of rogue black holes created in the centers of globular clusters has stirred some interest among black hole researchers. If the observations and models hold up, there could be a hundred of these rogues roaming the Milky Way Galaxy (although not near enough to affect us here on Earth).

The second is about two black holes and their interlocked orbits that have given astronomers a chance to confirm Einstein's General Relativity theory.

Check out the other big stories for yourself while I head out to the University of Texas for a tour of their supercomputing site, and then on to what has been assured to be Texas's best barbecue!!


  • The Sloan Digital Sky Survey announced its work studying a once-hidden population of powerful black holes tucked away behind clouds of gas and dust around the cores of galaxies where these strange beasts exist.

  • At the same time, Vanderbilt University astronomers are doing simulations that seem to imply that the Milky Way Galaxy may have hundreds of rogue black holes.

  • In other black hole news, a researcher from the University of Turku, Finland has discovered the most massive black hole ever, some 18 billion times more massive than the Sun. This discovery has implications for yet more confirmation of Einstein's General Relativity theory. (Note: I'm still trying to track down an URL for this one.)

  • Chandra X-Ray Observatory released a fantastic image of Centaurus A, a nearby galaxy with a supermassive black hole at its heart.

  • Harvard-Smithsonian Center for Astrophysics informs us that when worlds collide it could have resulted in a rather spectacular and mysterious-looking object that lies 170 light-years away. Another team at Harvard tells us that our home planet has been on the edge of habitability since it first formed.

  • Our friends at the Joint Astronomy Centre announced results from an infrared sky mapping project called UKIDSS (UK Infrared Telescope Infrared Sky Survey). Their findings are expanding the infrared sky for astronomers.

  • If high-resolution radio astronomy is your bag, the National Radio Astronomy Observatory (NRAO) announced the latest work they're doing with very large baseline array interferometry and astrometry.

  • Astronomers at Rutgers and Penn State universities have discovered galaxies in the distant universe that are ancestors of our own Milky Way Galaxy.

  • Hot off the press at European Space Agency is the news that the Earth-orbiting Integral satellite (sensitive to gamma-ray wavelengths) has discovered that the antimatter cloud at the center of our galaxy is lopsided. (More information here.)

  • For the folks at the Department of Astronomy at the University of Texas at Austin, a study of galaxies from HST and Spitzer observations shows that the mad merger-driven rush of galaxy interactions slowed down once the universe hit middle age.

  • The National Optical Astronomy Observatory announced the discovery of dark matter in accretion disks around a variety of astronomical objects.

  • In planet-forming research circles, there's news that a second wave of planet formation is orbiting two stars hundreds of millions of years after these stars first experienced their first wave of planet formation. (Note: the press release should appear on UCLA's site within the day.)

  • At the University of Arizona, astronomers point out that they are the first to successfully predict the existence of an extrasolar planet around a star about 200 light-years from Earth.

  • Finally, from my friends at Gemini Observatory, a beautiful image of the dance of two supernova remnants in the Large Magellanic cloud.


Okay, more later! Stay tuned.

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posted by CCP on 1/09/2008 02:23:00 PM | * |

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1.08.2008



AAS and the Cosmos



It's day one of the American Astronomical Society meeting, being held this week in Austin, Texas. Most of us from the colder climes are enjoying the little bits of shirtsleeve weather we're having here, even though we're mostly inside for talks and presentations.

The big news conference today was about the Hubble Space Telescope refurbishing mission, currently scheduled for later this year. Astronaut John Grunsfeld talked us through the mission sequence, and then demonstrated with a pair of astronaut gloves just how tough it's going to be to accomplish parts of the mission.

There are other news stories being reported here today. As is my usual practice I'll put some links here to them; later on I'll be posting a little video about the meeting and how it's going so far. Suffice to say, I'm psyched! It's a week of great astronomy and cool topics! This pic shows just HOW psyched...



TheSpacewriter and the Bad Astronomer and the Astronaut Gloves



Here are today's news stories:


  • The National Optical Astronomy Observatory has a stunning new image the Cygnus Loop, a supernova remnant in the constellation Cygnus. Check it out!
  • Elizabeth McGrath of the University of California, Santa Cruz, gave a very interesting presentation about some of the first massive galaxies to form in the universe. This is a very hot area of study right now as astronomers try to trace the evolution of structure (galaxies) in the cosmos.
  • NASA's Swift Satellite and Gemini Observatory are jointly probing a gamma-ray burst (GRB 070714B) that was detected in July, 2007. This work has put the age of the explosion farther back than astronomers previously thought short-burst GRBs were occurring.
  • You can read here about mysterious "blue blobs" in space seen by Hubble Space Telescope.These are orphaned clusters of stars near larger galaxies.
  • Finally, astronomers at Rutgers and Penn State universities have discovered galaxies in the distant universe that are ancestors of our own Milky Way Galaxy.

Okay, more later! Stay tuned.

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posted by CCP on 1/08/2008 04:02:00 PM | * |

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1.06.2008



Cold, and then Some



Up until a couple of days ago we were shivering under some pretty cold temps up here in New England. The other night we took the trash out and it was about 10 below zero (F)—cold enough to literally take your breath away. The sky was quite clear that night, and the stars were stunningly beautiful. Mars was like a red beacon...

The next day I walked out to get the mail and noticed the ice in the driveway. It reminded me of pictures I'd seen of ice fields on the worlds of the outer solar system. Out there ice doesn't so much melt off the surfaces of those worlds, but it sublimates—it turns from ice crystals into a gas without going through that pesky liquid phase we see here on Earth.

Oh, there is liquid water out there at the outer worlds. At least, that's the working hypothesis deduced from various observations. And, how else do you explain what looks like deposits of fresh ice that have somehow oozed up through cracks on the surfaces of places like Enceladus, Europa and Pluto's moon Charon? It's only a matter of time before the existence of all those cold oceans are confirmed. And, when I read about them, I can certainly sympathize with the idea of cold—especially after the bitterly cold weather we had last week. However, I am reminded that 10 below zero here on Earth would be a pretty warm day on Mars or Enceladus or Tethys or Pluto or Charon— so we have it pretty good here at home.

Speaking of cold and ice and outer solar system, here's the latest installment of my ongoing vodcast series. It features an observation made at Gemini Observatory that I wrote about a few months ago, and an image I worked on with the PR folks at Gemini. Come on—let's go visit some ice worlds!





To see this video here, you need to tell your browser not to block active content, or you need to get the Flash player. RSS readers who can't access the video can download it here.





Creative Commons License

This work is licensed under a
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posted by CCP on 1/06/2008 07:21:00 PM | * |

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1.01.2008




Happy New Year: 2008



It's the start of a new year and, as with many years past, I'm getting ready to go to the American Astronomical Society meeting in Austin, Texas. I've been a member since the mid 1990s and have been going to their meetings nearly every year since then.

Most years I try to post here about some of the latest and greatest and hottest news in astronomy and astrophysics that we find out about at the meeting. I'll do that again this year, and I'm going to try and put up a vodcast or two from the meeting as well. So, keep your eyes peeled for astronomy news and maybe a little video program with an "insider look" at the AAS meeting!

Also in the new year, I'll be working on more vodcasting for Haystack Observatory. We have a contract to do a series called Space Weather FX for them, and the first episode is up! You can watch it here as a flash animation, but by all means, go over to their site for downloadable versions and read the background info on the series and who's working on it. Eventually it will be syndicated to iTunes and other places on the web.

Finally, I've been working on updating my web site so, if you haven't checked out my other pages, head over to TheSpacewriter.com and see what I've done.



Space Weather FX Vodcast



Note: to see this video here, you need to tell your browser not to block active content, or you need to get the Flash player.


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posted by CCP on 1/01/2008 12:26:00 PM | * |

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