Star Stryder

Archive for May, 2007


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The Sun and its Danger Zone: The Chromosphere

One of the deeply confusing aspects of our Sun (and other stars) is their temperature structure. Starting in the core, the Sun is millions of degrees kelvin and supports nuclear burning. As you leave the nuclear burning core and climb first into the radiative zone and then the convective zone, the temperature systematically drops until it reaches a temperature of several 1000 degrees at a star’s surface. This makes sense. In the core, the gas is being compressed under the pressure of all the upper layers of the star gravitationally pushing down. The pressure allows nuclear reactions to release energy in a form that can heat things up: specifically light. That light then interacts with stellar material, being absorbed and reabsorbed over and over as it loses energy and goes on a random walk through the radiative region (think light bulb heating the air around it), and then (think of the lava lamp material above a light bulb) it also gives off energy as it heats cells of material at the base of the convective zone that rise and convectively give off heat as the cells rise (and then, when cool, sink back down).

So far so good.

The problem is, as you then move away from the surface of the Sun, you enter regions where the temperatures again go up - A lot - like back to millions of degrees hot levels of a lot!

And no one fully knows why. This is a very counter intuitive situation. Imagine that the surface of a lava lamp was 23C and the air half an inch away was 200C! In a press conference Wednesday, astronomers announced that they think they may have found a starting point for understanding what is going on in this bizarre situation.

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Party at the AAS

210_invitation.gifTonight there will be a celebration of community building involving cocktails. To get details, just get Out of the Rain. (or look at the card at left)
 
 
 
 
 
 
 
 
 
 
 

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Giving AAS a Face

img_9215.jpgThere is an excellant collection of photos from the conference (including one of yours truly) over at the 808scenezine.com that were taken by Katie Whitman. I’m still running around a bit madly, but I’ll be adding pictures to things. For now, get your photo fix here.

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“The Universe” on TV

theuniverse.JPGA new player has emerged on the science special scene. The History Channel is premiering “The Universe” tonight. You can watch “The Universe” Tuesdays at 8pm/9c. The first episode is on “The Sun.” Here is what they plan to talk about:

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All the news you’ll see again: Solar Atmospheric Heating, Tidal Tails, and Crab Nebula Explosion Date

Here’s highlights of the news I’ll be talking about later:

  • Scientists have (again) found new tidal streams of material around the galaxy from a previously unknown, now shredded galaxy
  • Scientists have (again) found a new explanation of how the Sun heats its chromosphere
  • Scientists have (again) dated the Crab Nebula explosion to 1054 AD
  • New results, new press conferences and press releases, and, well, the same old same old. Science moves forward in incremental steps, and sometimes things circle and circle as they slowly move forward.

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Black Holes and their Spin

There are two basic characteristics that describe black holes: Mass and Spin. Mass determines the size of the event horizon, the gravitational mass, and many of the ways the black hole can gravitationally shred people, planets and just about anything else. Spin is related to the magnetic field (which can also shred people because of the magnetic properties of water), and it exerts many relativistic effects on its surrounding, such as frame dragging. Black hole spin also allows the black hole’s associated accretion disk to extend closer in toward the event horizon, creating a (with future higher resolution telescopes) a directly imaginable effect.

In a trio of spin related press releases, scientists described how to measure spin, the consequences spin has on how black holes merge, and results on a test to check if our understanding is wrong.

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All that’s sorta new in Exoplanets

Yesterday’s big afternoon press conference was all about exoplanets. The scientists took us on a tour de force of planet related press releases that went from little M stars and their tiny habitable zone, to a new press release on 28 planets, to planets found around sub-giant stars that were A-stars when they were on the main sequence. The catch was, while none of these stories had previously had related press releases, many of them (but not all) had related published papers or published pre-prints in the arXiv pre-print sever.

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Galactic Morning: Andromeda XII, M81, and a Pushy Void

m81.jpgThis mornings first press conference spanned the scales of the Universe. From a high speed dwarf galaxy only 1/20,000 times the size of our galaxy, to a new picture of M81 (a nearby spiral galaxy - image shown), to information on how a lack of gravitational pull is causing the local group to wander away a local void, the scientists took us on a wild ride through the universe.

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An Apple World

appleworld.jpgShort message while I write longer content on this mornings first, galaxy rich, press conference.

This I walked into the press conference room and their was a giant, fresh from the press, printed Hubble Heritage image off to the side. Okay that’s cool.

What really caught my eye was the three scientists and their three Apple laptops.
And, at the back of the room, Apple affiliated folks (not sure, but I think Apple Employees) were recording the press conference to be podcast at some future date (will link when I know where to link to).

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The search for Chotchkies and Bling-Bling

One of the odd side activities at AAS meetings is the search for neat give aways from the different space missions, companies, and publishers. These items generally take the form of lanyards, pens, and posters. I picked up something kind of new and neat and just in time for pool parties last night : A WMAP beach ball depicting the cosmic microwave background. I’ll now be able to toss the fingerprint of the big bang around my classroom or back yard. There was also a happy cheerful button that proclaimed “I’m a Scientist” with a telescope and satellite.

And this was just at a pre-meeting dinner.

Currently, it’s looking like I should have brought a bigger bag.

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