The Stuff Between the Galaxies



February 28, 2009 at 11:23 am | 3 Comments

What is It?

This computer simulation by Matt Hall (NCSA) and Eric Hallman (Univ. Colorado) shows the warm-hot intergalactic medium (blue) that runs along filaments between galaxies and galaxy clusters.  (Click to biggify.)

This computer simulation by Matt Hall (NCSA) and Eric Hallman (Univ. Colorado) shows the warm-hot intergalactic medium (blue) that runs along filaments between galaxies and galaxy clusters. (Click to biggify.)

Living in a galaxy is like living in a big city.  There’s always something going on, there’s always somebody around. Even if you live out in the country, you’re still not that far from the nearest neighbor or town or burg or hamlet. But, let’s say you lived out in the desert, hundreds of kilometers from anything. You’d be surrounded by nothing, right?

Well, not exactly. It depends on how you define “nothing.”  If you think that a lack of towns or neighbors means there’s nothing out there, that’s one way to think of it. But, you’d still have sand and plants and animals surrounding you. They’re not in your social set, but that doesn’t  mean they don’t exist.

The same thing goes for galaxies and the space between them.  That space may look empty, but it’s  not.  Our galaxy is part of a cluster of galaxies called the Local Group.  The space between our galaxy and the ones next door is filled with material even though (to us with visible-light eyes) it looks like it’s empty.

While you may have heard that there’s a dark matter halo out there surrounding the Milky Way, there’s also regular old baryonic matter.

How do we know this? Bruce Dorminey, who writes for ScienceNow Daily News, sent me an article he wrote about a detection of regular matter between galaxies that was done using x-rays.

How so?  As light travels through the intergalactic medium, it encounters “stuff” — atoms of gases in clouds.  As light from more distant objects runs through those clouds, some of it is absorbed by the material.  We can actually see the fingerprints of this absorption when we look at that light through a spectrograph.

It turns out that these clouds are likely absorbing x-rays (which are also part of the electromagnetic spectrum). David Buote of the University of California at Irvine and a group of astronomers used the Chandra X-ray observatory and the European Space Agency’s XMM-Newton observatory to look at a portion of an object called the Sculptor Wall, part of a large collection of galaxies that lie about 400 million light-years away.  They were specifically looking for the fingerprints of O VII — oxygen that has been stripped of five of its eight electrons.  This O VII is part of what astronomers call the “warm-hot intergalactic medium” — a sort of rarefied plasma that absorbs various wavelengths of light, including x-rays.  Buote and his colleagues are saying that there’s an excellent chance that their discovery will hold up and that they have found another way to probe the matter that exists in the intergalactic medium. Their research will be published in the April 20th issue of Astrophysical Journal.

Astronomers have long known that the intergalactic void wasn’t completely empty, but this new work shows us what’s filling it in some places. It has pretty important implications for how we understand what astronomers call the “large-scale structure of the universe.”  This is because we are still trying to understand just how matter is distributed — whether it’s regular matter or dark matter.  In the long term, astronomers use studies like this to model just how galaxies are formed and how the universe has evolved since it began 13.7 billion years ago.





GOP Neutron Stars



February 27, 2009 at 11:59 am | 7 Comments

as a Metaphor for Density?  Stupidity?  Both?

This one’s too good to pass up.   I’m gonna have to go political on ya here.  I don’t do it too often, so if you’re looking for science, come back for the next entry, where I’ll be talking about some really deep cosmic stuff. If you don’t mind a bit of politics with your science, read on.

Okay, ready?

This week, GOP something-or-other hopeful,  former exorcist and current governor of Louisiana, Bobby Jindal gave one of the worst political speeches it has ever been America’s privilege to have heard. If he had any good points, they were lost in a sea of inadequacy and mistaken understanding of what’s really happening in this country. I expected better from him. Instead, we got dross.

I won’t go into great detail here, but it was funny/sad to hear him go after science the way he did. I suppose this is to be expected from a GOP hopeful who has to appeal to some imaginary voting base that thinks that science is icky and shouldn’t be funded (unless of course the science is being done in their home states).  I’m finding the whole uproar pretty funny, but if I were a GOP strategist with any brains, I’d be heading for the exits whenever this guy opens his mouth.

Well, it wasn’t long before science  blogs began picking up on Jindal’s anti-science rant against (among other things) volcano monitoring. I suspect that somebody on his staff saw that and thought it would be a good thing to rant against, since there aren’t any volcanoes in Lousiana.  There are, however, a lot of hurricanes that hit Lousiana, and the state is still struggling with the effects of them.  I wonder what Jindal would do if a fellow GOPper started ranting against all the money we’re spending on weather predictions and understanding how our climate works? Funny how he didn’t mention that…

Anyway, one of the blogs I read– called Weird Things– headlined its story on Jindal’s Rant “the GOP’s Rising Neutron Star.” It’s a funny read and makes entirely justifiable fun of Jindal’s words (and his other “accomplishments” in the world of science education in Louisiana). (Note: this is a great site to read — some posts are more “adult” than others  — and they ARE all thought-provoking and honest.)

Yeah, sure the neutron star monicker is a geek joke. But it’s a good one and a great pun besides. How so? Well, let’s look at what neutron stars are and how the description might be applicable to this specific person and his political party’s continually evolving (pun intended) stance on science.

Neutron stars are incredibly dense remnants of formerly bloated, massive stars that collapsed in on themselves in supernova events after belching out much of their outer atmosphere to surrounding space.  The material at the heart of these objects is a sort of degenerate gas, which means that it’s incredibly denser than anything in the universe (outside of a black hole).

Does that sort of fit with what’s going on out there with a political group that has lost its way? Yeah, it does.

We have incredibly dense ideas belching out from a bloated, massive group of politicians who are losing their mass. Their party is in a state of slow, but inexorable collapse under its own weight of missed opportunities, misleading opinion, and out-and-out political chicanery over the past 8-10 years.  They’ve become this sort of strange degenerate lump of matter that occasionally belches out these odd blasts against science.

Jindal’s not the only GOP neutron star out there. Former presidential candidate and science maladept John McCain is on the science warpath again. This time, instead of yelling about overhead projectors that he thinks are what planetarium projectors are, McCain is going after the ‘Imiloa Science Center earmark in the federal budget.  (Now, the issue of earmarks could be the subject of a separate discussion here, so if you’re going to yell at me in comments about that, don’t. That’s not where I’m going with this and I happen to think that all these things should be in the regular budget, but that’s beside the point here. )

McCain doesn’t like astronomy, does he?  Interesting, since he lives in and represents a state that gets quite a bit of money from the government for astronomy observatories.  (In fact, Arizona is one of a bunch of states (including Alaska and Louisiana) who get MORE federal tax money than they pay out.  Interesting, that.)

Perhaps McCain’s mad because Flandrau Planetarium in Tucson is closing down.  Who knows?  He’s found a good rant and he’s stickin’ with it.  And, I see that Jindal is sticking with his “anti-volcano” stance, too.  Fine. Let ‘em.  We’ll remember it the next time he bellies up to the science funding trough for some hurricane study money. And, when John McCain yells about planetarium pork or whatever’s on his plate for the day, we can remind him that there’s a perfectly fine planetarium in Arizona that could also use an earmark or two. (You can also read about Flandrau’s budget cuts and closure here.)

When it comes to science and science education, the U.S. needs to be revamping its efforts, putting more resources into those very subjects that have been the source of so much of our wealth over the years.  I don’t think any reasonable person would say that science funding hurts the country.  What’s hurting our country now is NOT the money being sent for research and development and education. And these clowns who yell about science know that. They’re just grandstanding for an increasingly shrinking, but frightened base of voters and lobbyists.  No doubt when the money comes down the sluice, they’ll take it but keep pointing their voters to the shininess of their Fools’ Gold-type anti-science rants.  That’s degenerate.





Venus in all Its Glory



February 26, 2009 at 14:54 pm | Leave a Comment

The Evening Star

Dont miss the final Moon-Venus conjunction of this seasons cycle. Theyll be a real eye-catcher at dusk on Friday the 27th, at least if youre in the longitudes of the Americas.  These scenes are always drawn for the roughly middle of North America (latitude 40° north, longitude 90 ° west). European observers: move each Moon symbol a quarter of the way toward the one for the previous date. In the Far East, move the Moons halfway. The blue 10° scale is about the size of your fist held at arms length. For clarity, the Moon is shown three times actual size. (Click to embiggen)

Don't miss the final Moon-Venus conjunction of this season's cycle. They'll be a real eye-catcher at dusk on Friday the 27th, at least if you're in the longitudes of the Americas. These scenes are always drawn for the roughly middle of North America (latitude 40° north, longitude 90 ° west). European observers: move each Moon symbol a quarter of the way toward the one for the previous date. In the Far East, move the Moons halfway. The blue 10° scale is about the size of your fist held at arm's length. For clarity, the Moon is shown three times actual size. (Click to embiggen) (Courtesy SkyandTelescope.com)

We went out last night for dinner and on the way to the restaurant we noticed Venus shining high in the west. It’s really gorgeous these nights.  If you  haven’t been out lately, take  a step out and look west after sunset.  It’s absolutely stunning, shining like a jewel up there. You can’t miss it.

Over at BadAstronomy, Phil Plait has a nice entry called Beauty Without Borders, an effort to get people around the world watching Venus. There’s a website about it, called BeautyWithout Borders: an Evening for Venus.

The event started last night and will go through March 1, so strap on your Venus-viewing eyes, step outside somewhere with a good view to the west and join millions of people around the world who are feasting their eyes on planet Venus.

While we’re all on the ground watching the Evening Star, the European Space Agency has been studying Venus with the Venus Express spacecraft.  Lately the mission folks have been studying up on an eerie infrared glow in the nighttime atmosphere of Venus. That glow occurs in the presence of nitric oxide and its presence is giving scientists a good view into the temperamental atmosphere of the planet — its chemistry and composition, as well as atmospheric  temperatures and wind directions.

The nightglow is ultimately caused by the Sun’s ultraviolet light as it encounters the atmosphere and breaks the molecules up into atoms and other simpler molecules. The free atoms may recombine again and, in specific cases, the resulting molecule is charged up with some extra energy that it radiates as infrared light.

The night glow on Venus has been seen at infrared wavelengths before, giving away the presence of oxygen molecules and the hydroxyl radical, but this is the first detection of nitric oxide at those wavelengths from an area of the atmosphere that lies above the cloud tops at around 70 kilometers above the surface. The oxygen and hydroxyl emissions come from 90-100 kilometers altitude, whereas the nitric oxide comes from 110-120 kilometers altitude.

Want to read more about this cool find?  The ESA folks have a whole web page up about Venus’s atmosphere. Check it out!

And don’t forget to go study Venus with your own Mark I eyeball set. This week we’ll be seeing the last Moon-Venus conjunction for a while in our evening skies over the  next few days.  Read more about what’s up tonight at SkyandTelescope.com.





The Eye of the Helix



February 25, 2009 at 13:35 pm | Leave a Comment

Look Deep

The Helix Nebula as seen by the European Southern Observatory. (Click to embiggify.)

The Helix Nebula as seen by the European Southern Observatory. (Click to embiggify.)

Well this is just stunning.  The Helix Nebula is a planetary nebula that lies about 700 light-years away from us. It’s what’s left over after a star like the Sun goes through its death throes and blows off much of its atmosphere to surrounding space. If you could float through the material to the central portion, you’d pass through shells of gas that were “exhaled” by the star. And, in the center would be the hot remnant of the old star, shining brightly in visible and ultraviolet light.

This image from the European Southern Observatory’s Very Large Telescope is full of detail in the surrounding clouds. For example, you can see little “blobs” of material that astronomers call “cometary knots”  — not because they’re comets (they’re not) but because they seem to have faint tails extending away from central blobs, pointing away from the star.

If you click on the image above you’ll get an enlarged version.  Look carefully at the central section of the nebula — you should be able to see galaxies in there!  The galaxies aren’t IN the nebula — they’re behind it, and the veil of gas is so thin that you can see much more distant objects right through it!

Go explore the eye of the  Helix — it’s gorgeous!  Want more information? Click here for the press release and links to zoom-in animations of the Helix.





OCO Lost



February 24, 2009 at 11:02 am | 4 Comments

Lost Chance to Measure Atmospheric Carbon

The launch of the Orbiting Carbon Observatory (courtesy NASA).

The launch of the Orbiting Carbon Observatory (courtesy NASA).

The news today about the Orbiting Carbon Observatory (OCO) failed to reach orbit and crashed into the ocean near Antartica is just too ironic. The OCO (the acronym is also a play on the chemical formula for carbon dioxide, CO2) was built to measure places where carbon dioxide is being emitted and absorbed on and around our planet. Antarctica is one of the bellweather places on Earth that atmospheric scientists study as they chart the effects of global warming. OCO would have taken measurements 30,000 times per orbit, including the atmosphere over Antarctica. That’s the kind of fine detail that scientists need in order to understand and model the complexity of our atmosphere as it soaks up more and more carbon dioxide.

This is a huge loss.  How is it that a fairing — the part that protects the payload on the way up out of Earth’s gravity well — could fail?  Human error?  Part failure?  Did a computer command fail?  No matter how it was caused, the loss of this satellite affects not just the scientists involved, but students who had designed experiments using the satellite, and — really — all of us.

Antarctica, from a NASA animation.

Antarctica, from a NASA animation.

Humans and our activities are the primary causes of excessive carbon dioxide levels in our atmosphere. That CO2 is part of the chain of events that are causing global warming. We need things like the OCO to help us understand the distribution, production, and absorption of CO2 if we are to make any definitive steps toward reducing the CO2 amounts we are pouring out each day from our automobiles, factories, power plants, and other polluting technologies. OCO is part of a larger effort to study and understand our planet — something we also do at other planets in order to understand their histories and environments. I hope that a replacement can be made for OCO — the knowledge it would have given us is information that we need.





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