"As always on this boulevard, the faces were young, coming annually in an endless migration from every country, every continent, to alight here once in the long journey of their lives." -Brian Moore
Even the Universe experiences a "great migration" every now and again, where giant, massive globules of interstellar gas are blown thousands of light years across the galaxy by their hot, star-forming surroundings.
And if I do say so myself, in the case of the Cone Nebula, it looks like the classic "V" pattern that migrating birds engage in. Of course, there are no birds here; this appears to be a gas globule in a dusty, hydrogen-rich region that's experiencing intense heating and evaporation.
Where's all that heat coming from? Whats responsible for creating this migrating pattern in space? It originates from a nearby region of space known as the Christmas Tree cluster, a set of stars that forms a very distinctive shape.
The set of blue stars forms an asterism, or pattern of stars in the sky, that looks like a Douglas Fir tree: a traditional Christmas Tree. But the "top-of-the-tree" is a hot, young blue star that's extremely close to our globule of gas, and it's thought that the stellar wind from this star, in such close proximity to our gas globule, creates the familiar, migratory pattern of the Cone Nebula.
And while this is the story of the migration of gases in the Universe, we have our own, local story to tell about migration. As many of you noticed, many posts, comments, and pages disappeared for a while over here. Not all images may display properly (including on this post, which is somewhat of a test), and there are problems uploading any files at the moment, with looming problems for large files. This is because we are migrating blogging platforms (which has been in the plans for many years), and there are many kinks still to be ironed out. They will be, of course: your still-missing comments will be recovered, the banner will return, my halloween profile picture will be back, your beautiful images of the Universe will return, and I will re-build the sidebar. (FYI, there is a lot of new spam to deal with, so don't be surprised if your comments get held in moderation for longer than usual.)
And then, in earnest, we'll get back to doing what we do best: exploring and learning about the Universe. Thanks for being such a valuable part of this journey so far, and thanks for sticking with me even through the rocky bits.
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Oh and don't forget to add your list of links. They are sometimes just the place to research something.
And what no preview capability. Now the preview capability is something that I really will miss and would like to see fixed and put back in. I use it a lot.
Yes, yes Ethan. I will stick with you because your blog is so excellent in so many ways. You strike a good balance. Teaching the basics, exploring the new ideas, not taking yourself and science too seriously (e.g. your weekend fun), being a place where we can ask our questions, sometimes get answers and have frivolous or serious discussions.
So No I don't like the change and won't until it is done and is the new routine. But I'm sticking with you and the so many excellent commentors who liven this place that you've created.
Thanks.
So "globules of interstellar gas are blown thousands of light years across the galaxy " by "stellar wind from this star".
So I assume these stellar winds are magnetic, thus maybe the gas is magnetic, thus we got galactic magnetic currents involved (maybe). I'm not trying to force an answer here. But thousands of light years doesn't seem so big on a cosmic scale.
So my questions ARE:
Are magnetic currents from stellar winds the primary mover of these clouds or is it particle collision or soemthing else?
Are astronomers able to see any magnetic currents or gas cloud movements on an inter-galactic basis?
Ethan, if possible, please keep the blog format with all the entries expanded. This new format with only a couple of lines per entry followed by a link is unconvenient. The old format allowed the reader to just continue reading - no fuss. Thanks!
I'll be faithful and true!
Tihomir,
I will note the request and pass it along. Unfortunately, I no longer control that with the new layout.
There are a number of more pressing fixes that need to happen before I am able to blog again, but I don't want to waste your time and energy with it; I just want to get back to writing about what I love and giving all of you a chance to enjoy reading it, ruminating on it, and sharing your thoughts about it with the world.
As I just posted over at Chad's blog, I don't care about how a site looks (with some limits!) I care about content, and science blogs content in general has been going downhill.
It's the content which keeps me coming back or drives me away. I used to read a lot more blogs here; now it;s rpetty much just yours, erv's, and Jason's and use the 'last 24 hours' button to find what has recently been posted. Today that button doesn't work, and neither does the drop-down box for selectign a blog. Yes, I can select a blog, no, the selection doesn't take me there!
Well, I guess functionality is another issue! My last comment somehow got posted without me specifically electing to do it and without my having a chance to correct it for typos, and unlike on Jerry Coyne's blog, you can't go back and make changes here!
Are magnetic currents from stellar winds the primary mover of these clouds or is it particle collision or soemthing else?
The gas clouds are primarily neutral, so this is a hydrodynamic (i.e., particle collision) effect. But there is an interaction between the magnetic fields of stars and the galactic magnetic field which plays a role here as well. It's like the interaction between the solar wind and the Earth's magnetic field, but on a much larger scale and with a much larger fraction of neutral gas. A couple of features in the first image look like bow shocks to me.
Eric Lund: "The gas clouds are primarily neutral"
I'm an outsider to astronomy for sure, but if I recall correctly, the interstellar gas clouds are usually described as a mixture of ionic atoms and molecules, which makes sense for me, because there's no containment chamber, and gravitational effects are too weak to put pressure on them, so it is easier to loose electrons and on a long term neutral hydrogen material would turn to a could of a bunch of protons (H+) and a electrons as the chances of recombination are much lower given the emptiness.
Being in a plasma-state which means that positive and negative charges are floating separately from each other. Magnetic force field is the result of moving electric charges, thus plasma has magnetic properties (hence the use of tokamak in the fusion research).
So if these gas clouds are electrically neutral, what's the reason? Why don't these gas clouds get ionized?
There used to be links to the next and previous articles so you could just click on the next article link to continue reading. Now you have go back to the blog page then find the next article.
for OKTHEN question when it comes down to it energy matter and even time have a magnetic force, so logically it would make sense that the wind have magnetic force