June 29, 2009 at 13:07 pm | Leave a Comment
We’ve arrived at our destination pretty much safe and sound — thanks to all of you who wrote to wish us well. I was going through all the news that’s piled up while we were on the road, and noticed a story about “warm” weather on Mars and how some landforms show evidence of freeze-and-thaw cycles that indicate warmer weather sometime in the past. Very interesting and a great object lesson in what you can learn by studying landforms.
Driving across the landform that is the Great Plains of the United States, I couldn’t help but think about how millions of years ago the whole area was under an ocean. The landform is gentle and and rounded, with a few hills here and there. Of course, we went through some of our own “warm” weather the past few days — sweltering temps and some pretty severe storms. Those are short-term compared to the long-term existence of things like oceans in the past or the yearly freeze-thaw cycle on Mars that spurred the recent finding. But, it’s all planetary science — and it’s all still in the landforms, if you know how and where to look!
June 26, 2009 at 23:07 pm | 1 Comment
I’m currently driving cross-country to a new home. It’ s a huge move; all of our stuff is on a moving van, we have us and the cats in our cars. The scenery this time of year is gorgeously green — at least along I-80. But, what has kept my attention both nights has been the sight of a lovely crescent Moon high in the west. One of the pleasures of skywatching is to see such sights and then let the imagination wander about how cool it is that we have another world so close that we can see its curvature without needing binoculars or a telescope. If we lived on a planet without a Moon, I often wonder how long it would have taken humans to intellectually figure out that other worlds exist, and what their characteristics are?
If you get a chance, get outside and check out the Moon the next few nights. It’s lovely!!
June 23, 2009 at 9:07 am | 3 Comments
Northern Hemisphere Style
Well, it’s high summer here north of the equator, and for those of you without incessant rains coming down from the sky, the stars must be lookin’ pretty good right about now. I always like to go out and look for Sagittarius, which from my latitude is pretty far south and the tail just grazes the horizon. There’s a lot of stuff out that way — the center of the Milky Way lies in that direction, and so do a number of nice star clusters and some nebulae. It’s one of my favorite places to look with binoculars. The Milky Way also skims right over head later in the evening, and if I can find a spot in the grass without chiggers or mites or skeeters (mossies, for those of you in Australia), it’s really rewarding to lay back and just gaze at that (with or without binoculars).
I remember as a kid doing that “laying in the grass and looking up at the skies thing” and trying to count stars. An impossible task. There are a few thousand, not counting the ones you’d need magnification to see (either too dim or too far away or too crowded together in clusters and the Milky Way). But, don’t let that stop you from trying.
Here’s a challenge for you: get out there every night and look up. Just do it. No excuses. Get a star chart (if you don’t have one, get one here: Skymaps. Print it out, study it. Then go out there and use it to identify a constellation or two. Maybe some bright stars. If you’re daring, you might see if you can find some clusters. They’re out there. And if the weather is good for you (warm, dry, comfy), try it every night. Go on do it. I dare ya. Me? I’ll do it, too. But first I have to find some clear skies. It’s been raining here for a week. And, for the next seven days, I’ll be absorbed in moving to a new house. But, I’ll check in with you, to make sure you’re stargazing. Watching the stars is free — and, as they say — in this economy — free is good.
June 21, 2009 at 10:25 am | Leave a Comment
Today’s what lots of folk think of as the first day of summer for us northern hemisphere types and first day of winter for the southern hemisphere folks. (It’s actually the mid-point, marking the point when the Sun is the farthest north in its yearly path across the sky.) Today’s the solstice and FATHER’s DAY here in the U.S…. and just in time for this auspicious occasion, the folks at National Center for Atmospheric Research (NCAR) and the Max Planck Institute for Solar System Research bring us a wonderful computer model of sunspots. I’m dedicating today’s entry to my dad, who loves to look at sunspots! This one’s for you, Daddy!
The high-res simulations of sunspots are an important tool for scientists to learn more about these blots of seemingly dark regions on the Sun (I say “seemingly” because they’re actually just cooler than the surrounding area, thus appearing darker). Sunspots are manifestations of the magnetic fields that play across the Sun’s surface. They’re also closely associated with massive ejections of material that can come straight at Earth and cause things like aurorae, or even go so far as to disrupt our communications networks and power systems. You may have heard of the term “space weather” — well, sunspots are often involved in the processes that cause space weather. If you’ve been following the Space Weather FX project I’ve been working on for Haystack Observatory, we’ve been talking a lot about the effects of space weather on all kinds of systems.
Creating detailed simulations of sunspots would not have been possible even as recently as a few years ago. But now, we have the latest generation of supercomputers and a growing array of instruments to observe the Sun — and when you marry the two, you can get some amazing simulations of real life. Partly because of such new technology, scientists have made advances in solving the equations that describe the physics of solar processes. The Sun is a complex object, ever-changing and difficult to probe. So, coming up with a computer model is an important step. “This is the first time we have a model of an entire sunspot,” says lead author Matthias Rempel, a scientist at NCAR’s High Altitude Observatory. “If you want to understand all the drivers of Earth’s atmospheric system, you have to understand how sunspots emerge and evolve. Our simulations will advance research into the inner workings of the Sun as well as connections between solar output and Earth’s atmosphere.”
Outward flows from the center of sunspots were discovered a hundred years ago, and ever since then, atmospheric physicists have been working on explanations for the very complex structures they see in sunspots. This includes the fact that their numbers rise and fall during each 11-year solar cycle.
The work was supported by the National Science Foundation, NCAR’s sponsor. The research team improved a computer model, developed at MPS, that built upon numerical codes for magnetized fluids that had been created at the University of Chicago. GO read more about it (and see some of their really COOL videos) at the UCAR/NCAR web site.
June 20, 2009 at 9:04 am | Leave a Comment
We’ve got another podcast up today at 365 Days of Astronomy, this one about magnetars. These cosmic beasts are in the news again this week, with the discovery of another one about 15,000 light-years away from us. Astronomers have known about these beasts since 1979, but didn’t really figure them out until a few years ago.
Now, they’re seeing them in various places, including this most recent one — which wasn’t even on the map until its outburst was detected in 2008. The outburst occurred when the unstable configuration of object’s magnetic field pulled on the magnetar’s crust, allowing matter to spew outwards in sort of exotic volcanic eruption. The outbursting matter tangles with the magnetic field which itself can change its configuration, releasing more energy.
There haven’t been a lot of these strange beasts located in the galaxy, yet. With this new one, the count comes to 15, but there will be more found as they wake up and send outbursts our way. The tools are out there to discover them — XMM-Newton and INTEGRAL are sensitive to the soft gamma-ray emissions of magnetars
So, go on over and listen to our podcast, and if you want more info about magnetars, I’ve got a page up here.
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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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