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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No, this entry isn't about a round of Diplomacy where Spain conquers the Ottoman Empire, although taking the day after a big holiday meal with family to play games is not a bad thing. It's more about the things you see as you're sitting out on the front patio of your folks' place after that holiday dinner, staring at the sky. I did that yesterday, as the nieces and nephews scattered themselves around the house playing chess and word games and generally being nieces and nephews, and some of the adults were talking and laughing in the kitchen and family room, and some of the rest of us were outside chatting.
So, from the front patio I could see the planet Mars, and then after awhile — as it got darker — the stars started popping out one by one. As we sat and talked, the sky got darker and the planes taking off and landing at the airport were forming their own constellation patterns against the backdrop. And I was thinking that as much as I love doing planetarium work and how unique the theaters are, it just doesn't compare to the ambiance of being under the real sky. They're two different ways of getting a feel for the star patterns, and what's up, but one is not the other. And that's not so bad, really. There's a time when you want to be under the real stars and there's a time when you want to be under the dome. Sort of like playing a game of baseball in real life or playing fantasy baseball online.
The size of the sky and the smell of woodsmoke drifting from someone's fireplace nearby, and the sounds of the kids playing, and the glittering, showy entrance of the stars in ones and twos provided a fine backdrop for the human interaction below... a pleasant holiday scene I won't soon forget.
The image below kind of evokes that feeling — it's not my image, but one I found when I was surfing around looking for images of the desert a few weeks back. Scott had the luck to be under a clear desert sky one night and took advantage of it to capture the beauty of the stars.
A few months ago I was flying somewhere and reading a book on astronomy when the guy in the seat next to me took an interest in the subject. Eventually, as it always does when someone strikes up a conversation about stargazing, the topic of learning the stars as a kid came up. "I haven't actually done anything with astronomy since I went to the planetarium on a high school field trip," was his statement. Since I do a lot of stuff with planetarium facilities, I drew him out about his experiences and gained another data point about the importance of these ubiquitous facilities in our educational and recreational lives.
Planetaria ARE ubiquitous, but they are in some ways part of an endangered species. They pop up in waves and close down, maybe not quite so quickly. In the past few years the idea of the planetarium has been evolving. For most of us of a certain age, they were the funny round rooms with the "ant" in the middle — that we visited in museums and some well-equipped school districts. The Ant refers to the big opto-mechanical star projectors that still sits in the center of the room in many facilities and splashes stars out across the dome. Then folks started adding slide projectors and video systems, and now today's star theaters are benefitting from the advent of the Internet, the Web, and all sorts of other technologies. And while some are opening up, others are closing. The planetarium facility — and its technologies are changing and improving while other dome technologies are fading away.
So, do you go to your local planetarium? What's happening down at the star theater? Are these places relevant to today's education and recreation? Those are the questions that run through my mind as I create shows and ponder the future of the medium. It's a unique medium, one that many of us have spent years mastering. It's certainly not like anything else in the entertainment/educational outreach world! From the simplest (yet most wowie) special effect of a night sky (stars alone) to the 3D technicolor space voyages some producers are turning out, a night at the planetarium is still one worth your time and effort!
As Americans and their families head into Thanksgiving week, the Sun is getting in on the act by showing off several huge sunspot groups that are candidates for solar flares over the next few days. In addition to the SOHO and Spaceweather.com websites for updates on geomagnetic activity and aurora forecasts, you can also surf over to Space Weather Now.
These sites are your best sources for "up to the minute" space weather information. Here's what Spaceweather.com has to say on Sunday, November 23, 2003:
SOLAR OUTLOOK: Big sunspot 488 has a complex "beta-delta-gamma" magnetic field that harbors energy for X-class solar flares. Any explosions from the active region this week would be Earth-directed, which raises the possibility of more solar storms and auroras in the days ahead.
And, over at Space Weather Now you can check out the size of the auroral ovals. Here's an example of a North Pole auroral oval on Sunday, November 23.
Courtesy of the Solar & Heliospheric Observatory — this image is updated frequently so you can follow the progress of these active regions across the solar disk. (SOHO)
It's acting up again. In late October it was quite busy with flares and coronal mass ejections that subsequently impacted the Earth's magnetosphere — and subsquently lit up our skies with auroral displays, disrupted communications and other services, and generally made solar and atmospheric physicists very happy with lots of new data to study. You thought it was over, right? Well, not quite. As it turns out, with the Sun, what goes around comes around. And, the sunspot regions that were responsible for the last space weather storm, that rotated around to the other side of the Sun, are on their way back. In fact, this image from SOHO's Extreme Ultraviolet Imaging Telescope (EIT) shows the three regions (in bright white) that are going to make life interesting for everybody for the next week or so.
Does this mean we'll be seeing more aurorae, tracking more flares, battening down the electronic hatches to save our satellites from heavy spaceweather? Maybe. There was another flare last week that lit the skies with aurorae, and chances are it'll happen again. So, keep your eyes peeled, visit the SOHO site, and Spaceweather.com for regular updates on what the Sun is doing.
On November 23, 2003, total eclipse of the Sun will be visible from a narrow track across Antarctica, while a partial eclipse will be visible over the tip of South America and parts of Australia and New Zealand. It will occur between 5:24 and 6:14 p.m. Eastern Standard Time. The folks at Sky & Telescope have a group scheduled to fly over Antarctica at an altitude of 38,000 feet. Those aboard will experience 2 minutes 26 seconds of totality — 29 seconds more than is possible from the ground. Other expeditions include a group from the University of Arizona, doing a similar flyover to catch the eclipse from planes laden with scientific equipment. And, of course, there are sea and land-based trips for folks to get their "umbral" fix that way, as well.
So what's the draw of an eclipse? I've traveled to five total solar eclipse paths since 1979 and have seen 3 full totalities. The others were clouded out. There is no way to completely describe the awesome sight of the Sun gradually disappearing behind the Moon. But it is awesome. And it makes you want jump and shout and turn all about... so, I can completely understand the need of umbraphiles to get more umbra.
I won't be along with them this time but I will try to follow along on my computer on Sunday night as the excitement begins. Want to join me? If you aren't on one of the many expeditions bound to the southern hemisphere to see this event, check out these links:
SkyandTelescope.com. They'll be posting images on their site sometime after the plane lands.
Also, the Discovery Channel will be airing the eclipse live on Sunday night during a program called Discovery Special Presentation: Solar Eclipse Live from Antarctica. Check your local schedule for showtime listings.
Somebody sent me this blog entry today from another guy's site. If you're a Monty Python fan (particularly if you have memorized Monty Python and the Holy Grail), you'll recognize it already. Go check it out. I love this sort of creativity with science and entertainment!
I've been cleaning out my filing cabinets lately, trying to rid myself of the paper and other stuff that accumulates through the mail, meetings, etc. I had two filing cabinets full of old press releases from science institutions. Most of them came my way at American Astronomical Society meetings. I usually register as press when I go (usually because I AM writing something for somebody), and thus these tidbits of research come my way.
One that I ran across that I decided to keep was a story about wide-field images of the center of the Milky Way taken using the Very Large Array radio telescopes. Nowadays it's an accepted fact that there is a black hole in the center of the Milky Way. The past few years, astronomers have been perfecting techniques to zero in on the culprit and take the measure of its size and mass. You don't actually see the black hole because — well... it's black. Or, rather, it's not allowing any light to escape from itself. But, you CAN see its effects on surrounding material — stars, gas, and dust. They give off emissions for various reasons related to the existence of the black hole — such as heating due to the strong radiation given off by material as it spirals into the hole. And some things here glow due to a whole raft of other causes. Unraveling what's what in this area is a full-time job for a lot of astronomers!
However, much of this activity is still invisible to us at optical wavelengths (that which we see with our eyes) because the middle of the Milky Way is hidden behind a veil of gas and dust. So, astronomers use radio and infrared and other "probes" to peer behind that veil. All the features you see in the image radiate at a wavelength of 90 centimeters (in the radio portion of the electromagnetic spectrum), and these features are related to the black hole — which is the largest, brightest object, labeled Sgr A. The actual black hole is hidden deep within that blare of light, and it is called Sagittarius A*.
As you can see, Sgr A is clearly not the only source of emissions in this image. Hot young stars form in this region, and as they do, they heat the gas around them. Eventually, the gas becomes hot enough that it glows, giving away the position of starforming regions. These are labeled Sgr B1 and B2 and part of Sgr D. When these same stars run out of fuel, they explode as supernovae, spreading debris in shock waves, and glowing in emissions given off as high-speed electrons spiral around magnetic fields. There are several supernova remnants in this image — look for the objects with the letters SNR in front of them. This radiation (called synchrotron radiation) may also be what's causing a collection of sources known as the Galactic center arc, filaments, and threads to glow.
Since I received that press release (in 1999) more research into the goings-on at the center of the Milky Way is zeroing in on details in these structures. If you're interested in learning more, you can visit the web page where this image is posted: The Galactic Center or there's a good book out from a guy named Fulvio Melia called "The Black Hole at the Center of our Galaxy" (Princeton University Press, 2003) that takes the reader on an amazing journey to visit this cosmic beast that is the center of so much activity!
And, just for grins, here's an infrared view of the center of the Milky Way, taken using the Keck II telescope in Hawaii, outfitted with an infrared-sensitive detector. Click here for more information and a detailed image map.
I spent last week working on a story about a local group of scientists who are tracking the space weather associated with solar flares and coronal mass ejections. It was published on the MIT web site here. One of the scientists I talked to mentioned that the same sunspot group that caused all the ruckus in late October will be rotating around Earthward again very soon and we could face more space weather in the next couple of weeks.
I find all this rather fascinating because it's further proof that the Sun and Earth are linked not just by heat and light, but by interactions between our magnetic field and solar plasmas as well. We see the heat and light of course, but the other stuff is more or less flying under our radar screens, so to speak. Well, the guys over at Haystack Observatory do actually aim radar beams at the upper atmosphere of the Earth (the ionosphere) to measure how it changes as our planet is hit with each onslaught of space weather. Events like the recent outbursts are their bread and butter. Talk about star power!
the European Space Agency and its spaceweather site. Follow for yourself over the next couple of weeks and see what kind of activity keeps the solar physicists and atmospheric scientists hopping! Plus, if we're lucky, maybe there'll be some more aurorae to watch as they light up the sky.
I went over to one of those big-box bookstores last night looking for a science book. It was something of a hunt to find what I was looking for because this store (part of a chain that touts its nobility and claims it sells everything) hides most of its science books on a few shelves 'way back in the corner, stashed in like poor stepchildren with the computer books. You almost have to know that they're there. Kind of a shame actually, considering they have stuff like astrology and crystal power and religion and self-help out in the middle of the store where you can't help but stumble over their sumptuous rows of books on the subjects.
Note: there's nothing wrong with having books on those subjects. What I'd like to see is some balance in bookstore selections. While bookstore owners may mutter at us that they only stock what sells, I do think one could make a case for doing a better job selling what one stocks... and being democratic in what one stocks. The cosmos is just too fascinating to closet away the good stuff almost as if the bookstore doesn't quite know what to do with books on astronomy and space science and geology and biology and other science subjects.
What have we come to that readers looking for good science books have to wander almost fruitlessly through this barn of a store looking for what they want? What message does it send to people when science is hidden away so it doesn't take away from sales of the almost-soft-porn books about girl pop singers or the latest blockbuster by Tom Clancy or the Nth book in a pictoral series on travel? All those are well and good (mind you, I'm a Tom Clancy fan myself) but it seems to me a little balance is needed — at least at THAT particular store.
Of course, I'm somewhat biased, since my own book is due out on the shelves in the next two weeks — it's a book about astronomy (read more about it here: Visions of the Cosmos) and I'd sure like to be able to point people to where it can be found in that big store. Thankfully one of my favorite stores, Borders, doesn't hide their science section, although I do notice that it has shrunk a little bit. Of course, you can always order books through Amazon (I've helpfully included a link on the afore-referenced page for my own book — plug, plug).
But, I fear that we are fast becoming a nation that abhors science at the same time we're living off the fruits of science. Are we sort of like the meat-eaters who love a steak but don't want to know about how that steak gets from live animal to grill? Or the mushroom-lovers who'd rather not be aware of just exactly what it is that their portabellos and shiitakes are growing in? I hope not, but with the proliferation of books that promulgate nonsense like crystal power and using the stars to guide your destiny and so on, it gets frustrating to see perfectly wonderfully written science works get thrust aside in a given bookstore. I blame people who are afraid of the beauty of math and the magnificence of science for relegating science books to one side. It's like people who buy computers but don't bother to read the manual on how the operating system works. Wait. Maybe that's not a good analogy. I don't always read those manuals...
Okay, how about this: I'm not religious at all, but imagine a Christian without a Bible, or a Moslem without a Koran, or a Buddhist without the works of Buddha to instruct on the precepts of individual belief systems. Science books provide an explanation of the cosmos. Sure, they sometimes use a language that looks like this:
v = Ho * d
or
(λ - λo)/λo = v/c
and such stuff scares the holy bejeebers out of those who see only the math and interpret THAT as science. The math is a language and it's only one of many that describes what happens in the cosmos, from physics to biology to medical science to geology to chemistry. Another way to learn about the cosmos is to read blogs like this one, or webpages like my site or some of the sites I have listed at the left. There's more than one way to approach science, but I can guarantee you, if you don't approach it, or worse yet, let bookstores determine how important science books are, you'll lose out on an amazing dimension of existence!
The great age of planetary exploration began back in the early 1960s with simple (!) probes to the Moon and Mars. Probably the best-known planetary explorers (to the public, anyway) have been the Vikings to Mars, the Mars Global Surveyor, the Mars Pathfinder, the Voyager missions to the outer planets, and the recently-ended Galileo mission. Today we have more spacecraft on the way to Mars, scheduled for arrival in early 2004, and the Cassini Mission to Saturn.
Cassini has not been sleeping on its way out to the ringed planet. Its most recent picture is of Jupiter and as you can see, it's a beauty! This true color mosaic of Jupiter was made from a series of 27 images taken by Cassini's narrow angle camera on December 29, 2000. At the time the spacecraft was doing a flyby of the planet and gaining a gravity assist to help it on to Saturn. This is the most detailed global color portrait of Jupiter ever produced. The smallest features you can see in this image are about 60 km (37 miles) across.
My favorite bits about Jupiter are the Great Red Spot — the storm just below the center of the image — and the swirling cloud tops in the belts and zones of the planet. Three Earths would fit comfortably across the spot — it's that big. The smaller storms would be huge by Earth standards, covering most of one hemisphere in clouds and battering it with high winds.
In the range of strange in this solar system, Jupiter seems weird to us — but when you think about it, four planets in the solar system are gas giants (Jupiter, Saturn, Uranus, and Neptune). Four are "hardbodies" (Earth, Mars, Venus, Mercury). Pluto is a hardbody with a covering of ice. So, really, Jupiter isn't all that weird. But, to us on Earth, used to breathable air, reasonable winds (as opposed to the highest windspeeds of around 650 kilometers per hour (about 400 mph)), and a solid surface, Jupiter probably does seem like kind of a colorful, but alien place.
While this is a close-up view from a spacecraft near Jupiter, you can get your own view (just not as detailed) of the planet in the night-time sky. This time of year (November), it's low in the eastern skies right around 10 p.m., smack in the middle of Gemini. If you can (and you're dressed warmly enough), wait until midnight, when it's a little higher in the sky. It will look like a really bright star, but it won't be twinkling and if you look at it through binoculars or a small telescope, you'll see that it's a planet! I'll write more on it later on this year, but don't hesitate to go check it out. Here's a finder map:
Even though this is sweeps month for TV and all the networks are trotting out their "finest" (read: most dramatic, salacious, violent, etc.) programming, chances are if you're a child (or an adult who acts like a child), you've heard (or said) that wonderful whine many times.
Well, what are you waiting for? Get the whiners outside and do some stargazing! Just step outside and look up. If you're not looking at cloud bottoms, you're looking at stars (probably through some light pollution). So, what's overhead these mid-November nights? Well, the Moon presents a nice observing target. Get that pair of birding binoculars out of the closet and use them to check out the craters and mountains. I don't know when you'll be looking, but if you want a hint as to how it will look tonight (or any night you go out), check out this page.
I like to look at the Moon. The craters are fascinating, especially when you think about how many of them date back about 3.8 billion years — to a time when the solar system was a little over a billion years old. That seems old to us — although in the span of the universe's age (about 13 billion years), the solar system is but a baby.
The universe does stuff like that you. You're standing there looking at the stars or a planet or something and next thing you know you're thinking about the age of the cosmos and how old the planets are and then you remember that people have only been around a small, small fraction of time.
In all the years I've been talking about astronomy, I've always told people there was no such thing as a dumb question. And I meant it. That hasn't stopped people from trying to come up with 'em though. Today's deep question comes to us courtesy of my niece Oriana, who said she heard this one on TV: "How many corn dogs does it take to fill up a black hole?"
Well, Oriana, I bet you thought I wouldn't try to answer that because it was too dumb. Truth to tell is you probably can't come up with an exact number of how many corn dogs it would take to fill up a black hole, because, well... because the obvious answer is that you can't fill up a black hole. The buggers just keep swallowing things up, getting bigger and bigger all the time. They're weird animals that way. You can chuck all the corn dogs in that black hole that you want, and it'll just keep sucking them down. Yeah, it's a trick question, but what do you want from an advertising copywriter who probably thought it was a cute "astronomy" thing to ask in an ad about trucks?
You wanna know more about black holes? I have a scintillating discussion on my web page that invokes Star Trek, Sherlock Holmes, and the Hubble Space Telescope. Go over here and read it and then come back here and leave me a comment if you think there's another way to answer the corn dogs-in-a-black-hole question!
The supernova depiction at Chaco Canyon Copyright 2002, Mark and Carolyn Collins Petersen
A year ago we vacationed in Chaco Canyon in New Mexico for a couple of days. One of our goals was to hike out to the site of a pictograph drawn on a rock overhang that is said to depict the appearance of a supernova that occurred in 1054 A.D. The artist was part of the Anasazi group of people who populated this canyon during that time, and much archaeoastronomical debate centers on just what it meant for the artist to paint the scene.
It must have been an eerie sight when the explosion flared into view over the eastern horizon early on July 4, 1054 A.D. Perhaps it had some ritual meaning to the Anasazi. Or maybe it was just their way of recording a strange thing in the sky. We'll never know, but that doesn't stop learned astronomers and ethnographic types from tussling over what the rock record means. One thing's for sure, the presence of a bright "guest" star must have been a surprise to ancient stargazers who knew the skies quite well. Certainly the Chinese and Japanese thought it so remarkable that they recorded it in their writings, and there's even evidence that people living on Guam noticed this outburst and drew pictures of it on cave walls. But, apparently, few in Europe saw fit to record this apparition, although it would have been quite bright in their skies.
Can we see the supernova today? Well, yes, sort of. It has faded quite a bit from the glory days of 1054 A.D. when it rivaled the full moon for brightness. To see it with any detail you need a medium-to-large backyard-type telescope and maybe even a filter or two. It's definitely not a binocular object but if you want to just see where the Crab lies, look toward the horns of Taurus the Bull after they rise up out of the horizon clutter on these November nights. The southern horn of the Bull extends out to a star called Zeta Tauri. The Crab lies just above that star.
Chart made using Cartes du Ciel software
Of course, observatory scopes are really good at digging into the heart of the Crab and showing us the spectacular details of this explosion. Here are two of my favorites: the first is from the European Southern Observatory and the second is a combined Hubble Space Telescope and Chandra X-Ray Observatory image:
I often wonder what the ancient Chinese, Japanese, and Anasazi peoples would think if they only knew just what it was they were recording on their parchments and sandstone? For them, this sight was a mysterious one — another symbol of something in the sky that they didn't understand. But they surely appreciated the beauty of the apparition — just as today we look at it and try to comprehend the stellar forces at play in the death of a supermassive star.
Yes, we went out in the subfreezing temps tonight and watched it from just after the eclipse started until about 15 minutes after totality ended. This is one of the pics we took with one of our digital cameras. First time we've actually tried any astrophotography with them. I'd like to try attaching one to the telescope one of these times — that'll take some practice, but hey... chip space is not at such a premium anymore, and if I don't like an image in preview I can slay it and try again. Ah the wonders of modern photography!
Still, as an old film photographer, there's just not quite the range of " expression" from a digital camera that I got used to with film. Does the instant gratification make up for it? Well, yeah, in a way. I get to come in here and upload a photo within a few minutes of taking it, do a little cropping, and then voila! Here it is.
The moon did look a little reddish, although I'm not sure if it was quite THIS red. However, I didn't want to mess with color balances on the image, so I left those alone and simply cropped some of the black away and centered the Moon. It was a great-lookin' eclipse and very pretty against the starry sky! (Unfortunately in this exposure, the stars didn't come through — I could expose for Moon or stars, but getting both in was a bit dodgier. Good news is that we didn't have speck of cloud anywhere and we got to see a very pretty and awe-inspiring sight!
I hope you got a chance to see the lunar eclipse tonight. Write to me and let me know how the eclipse looked for you!
Back in 2002 an astronomer using the Nordic Optical Telescope was studying a planetary nebula called the "Cat's Eye." To backyard scopes it appears like a complex-looking little puff of light and in fact, is a difficult object to find unless you have a pretty decent scope. Scientists like to study these nebulae for a number of reasons — for one thing, they give us a good idea of how our own Sun might die in a few billion years. For another, these ancient stars are putting out tremendous amounts of material into the interstellar medium — stuff which eventually will end up in the birthplaces of future stars and maybe even a few planets.
As these stars age, they puff off their outer atmospheres, forming a bubble of gas and dust in surrounding space. Eventually the radiation from the star lights up the outrushing debris, and sometimes the influence of a companion star, or a magnetic field, or a fast, hot jet of gases from the dying star, will sculpt the cloud into fantastic shapes. The Cat's Eye is a cavern of gas and dust surrounding an ancient star and possibly a nearby companion. The interactions have shaped the surrounding materials and the star's emissions have turned the whole sight into a glowing "cave" structure.
This fantastic picture shows various gases lit up by the star. Here's how the scientist who did the observation — Romano Corradi — explains the colors:
"I put in green and blue for the ionized oxygen emission; I used two colours for a single emission line because of the large dynamical range of the nebula+halo (there is a contrast of 1 million between the faintest and brightest structures detected), and I wanted to display the three different components of the nebula, i.e. inner nebula, first halo with the (in blue) rings, and outer filamentary halo. Red is instead [NII]6583. The image is the deepest ever obtained of NGC 6543."
A few years ago the Hubble Space Telescope studied the inner portion of the Cat's Eye — the "marble" surrounded by loopy looking structures at the center of this image. They, too, color-coded the image to map the different kinds of emissions put out by the clouds. This "astro-chemical" analysis tells astronomers a great deal about the age of the star, the layers of its atmosphere it has lost, and what kinds of elements are being returned to space for the next generation of stars and planets.
Click on the link to see an animation of the 10/28/2003 solar outburst as seen by the SOHO satellite!
As luck would have it, last week we happened to be out of town when a huge coronal mass ejection (CME) burst out from the Sun and sped on its way to Earth. Normally these solar wind gusts rush out at about 1 kilometer per second, but this one doubled the speed limit, blasting across space at 2 kilometers per second. Solar physicists were amazed at the sight they were seeing from the SOHO spacecraft. Radar operators, HAM operators, owners of satellites, grid systems, GPS units, and communications links, and oil and gas pipelines — not to mention the folks up on the space station — girded themselves for a big geomagnetic storm. We got it! On the 29th, Earth's skies lit up with auroral displays and there were some outages in telecommunications and other industries. Personally, we missed yet another great chance to see the aurorae — folks here in New England tell me they saw a glowing red sky with moving fingers of light overhead. Darn!
Hard on the heels of that storm came another massive ejection — in fact the most massive ever recorded — on November 5, 2003. SOHO caught it, as well as the GOES weather satellite. Its view in soft x rays is shown below. Theoretically we have a chance to see aurorae on the night of the 6th, but I'm not holding my breath. It's been cloudy here all day and the weather forecast doesn't bode well.
Most folks have heard (or are faintly aware of) the fact that our Sun goes through an 11-year-long cycle which culminates in a period of solar maximum — a time when the Sun is very active. So, are we seeing solar max? Nope. In fact, solar max ended last year and the Sun is now headed toward solar minimum, when sunspots are theoretically fewer in number. Still, as the Sun has shown us this past week, it still has a few tricks up its sleeve as it slides toward its supposedly quiescent period. And there's no reason to believe it will stop. The coronal mass ejections at the root of the huge outbursts are caused by solar magnetic events that release huge amounts of energy. The Sun's magnetic fields get coiled up tighter than rubber bands as it rotates through its 27-day cycle. Something has to give, and its usually the magnetic fields around sunspot regions. When they do, watch out! A coronal mass ejection is in the making — lighting up our skies and making life interesting for all the folks who study Earth's magnetic field interactions with the solar wind, GPS users, grid owners, and many others whose equipment is affected by geomagnetic storms.
Humans have the most amazing propensity to use animal "avatars" to illustrate things. A couple of entries back I wrote about cats in the sky. There are also sea creatures and even birds and bees up there! But the animalization of space isn't limited to constellations. This deep-sky object is called the Horsehead Nebula — for the obvious reason. It's actually a cloud of gas and dust that happens to lie in front of a bright, glowing cloud of gas and dust. The superposition of one over the other gives us the lovely vision of a horse's head.
This high-resolution image from the European Southern Observatory takes what looks like a serene scene and shows us how very chaotic the situation is at this nebula. You can see wisps and filaments in the gases, and clouds of diffuse dust. If you look at the top of the figure you see a bright rim separating the dust from the gas cloud (also known as an H II region). Astronomers call this region an "ionization front" where the photons from the HII region are moving into the cloud. Their energy is emitted as heat, which is destroying the dust and the molecules and lighting up the gas.
Actually, the Horsehead is a short-lived object. The continual erosion of the gas and dust by the emissions from nearby stars will eventually destroy the clouds in a few thousand years. So, enjoy this deep-sky animal while we have it!
Lurking within the confines of the constellation Taurus, the Bull, is the Crab Nebula, so named because through smaller telescopes it appears as a crab-like ghostly apparition. In reality, this thing is an expanding cloud of gas and dust marking the spot of a cataclysmic explosion called a supernova. It first shone in our skies in the year 1054 A.D. and was observed by the Chinese, Japanese, and very likely the Anasazi tribes of the American Southwest.
The Crab contains a neutron star near its center that spins 30 times per second around its axis, the remains of the original star. It flashes light pulses 30 times a second (making it a pulsar). In this picture, green light is predominantly produced by hydrogen emission from material ejected by the star that exploded. The blue light is emitted by very high-energy electrons that spiral through a huge magnetic field twisted around the pulsar.
Of course we don't see any of this through our backyard-type telescopes — for most of us this just looks like a dim little glow in the sky, hidden more than 6,000 light-years away and unlikely to do us any harm.
I just got back from a week's vacation in sunnier climes and was surprised to see one of my rose gardens still blooming after a snowstorm and some chilly rain while I was gone. We've had something of a mild autumn this year in New England, and some flower gardens are still glowing madly away, basking in the last warm weather before the snows start in earnest. This little tub of roses is dedicated to the memory of Caroline Robinson, late wife of Leif Robinson — a former colleague of mine from Sky Publishing. She loved to garden, and when I was planting these little Canadian roses earlier this year, I thought of her and her fight against cancer. A few weeks ago we attended Caroline's memorial service and I thought about these roses out there, still blooming this late in the year.
Another set of blooms arrived in my computer's inbox today — this set from the European Southern Observatory. These roses are really giant clouds of glowing hydrogen gas coloring the space in the Large Magellanic Cloud — a satellite galaxy of our own Milky Way. This European Southern Observatory image captures the beautiful sight of a 1,000 light-year-wide HII region (consisting of hydrogen gas being lit by radiation from 40 very bright bluish-colored stars) called N44. Astronomers studying this cloud think that some supernovae have exploded in N44 during the past few million years, "sweeping" the surrounding gas away from the supernova sites. Hot stellar winds from other massive stars in this area are blowing bubbles in the surrounding gases, twisting the material into wispy filaments and bright knots.
A small programming note: regular readers of this blog may notice that I'm fiddling around with the layout and template design. I hope to be through messing around with it soon but I do appreciate your patience while I figure out what I'm doing!
Also, have a look over at the library and gift shop on my website. I've been adding some holiday gift ideas at the suggestion of several readers who have been writing to ask me about the perfect gift for that stargazer they know. I've got links to books, telescopes, binoculars, star charts, space music and many other items — some with links to Amazon.com (which itself has loads of details about these products as well). Happy browsing!
The sites below belong to space and astronomy enthusiasts. I make every effort to check them and make sure they are still appropriate. However, I am not responsible for their content, nor do I endorse any of it by simply linking to them. As with all Web surfing, please exercise caution.
Adot's Notblog A fellow traveler blogger and astronomy enthusiast!
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