Galactic Interactions

Astrophysics in Second Life : 7D mapping of the Galaxy with SDSS

Posted on September 27th, 2008 — permalink

Yesterday (Friday Sep. 26), MICA heard its first Journal Club of the academic year. (We’ve had these before, but it was very slow over the summer.) The talk was Mario Juric from IAS Princeton, talking about mapping density, velocity, and metallicity as a function of spatial position within the Milky Way galaxy, using photometric data from the Sloan Digital Sky Survey.

click for a larger image

There were a few conclusions that came out of this. First, unsurprising to anybody who’s read anything about the structure of the Milky Way, the disk and the halo really are completely separate components. The disk appears to have a vertical (i.e. perpendictular to the plan) gradient of metallicity, whereas the halo has a constant (and lower) metallicity distribution. Some density outliers from the smooth background are there, which were known previously, including the Monocerous Tidal Stream discovered by my friend and one-time collaborator Heidi Newberg

However, there were also some surprises. There’s basically no gradient of metallicity radially along the disk. I had previously been under the impression that the disk had a metallicity gradient, with higher metallicities towards the center. One caveat to this: the data does not include the very center of the plane of the disk, so there may well still be a metallicity gradient within the plane.

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“Planets Around Other Stars” — talk in Second Life this Friday at 8am PDT

Posted on July 31st, 2008 — permalink

I’ll be giving the latest in the “Dr. Knop Talks Astronomy” series of talks associated with MICA this Friday at 8am SLT (aka PDT). The talk will be at the Galaxy Dome in Spaceport Bravo. The topic is Planets Around Other Stars:

Until the last decade of the 20th Century, we knew of exactly one star system that had planets: our own. At the dawn of the 21st Century, we knew about a few handfuls of exoplanets, or planets around other stars. Today, we know about more than 200. In this talk, I’ll describe the history of exoplanet searches and discoveries, I’ll describe the methods that we have used to find planets, and I’ll give you an update about the current count and nature of exoplanets that are out there.

Remember that a basic Second Life account is free!

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Academia : do I miss it?

Posted on July 13th, 2008 — permalink

Ethan Siegel asked me a question in a comment on an earlier post: do I miss it?

It’s rapidly approaching a year since I began working for Linden Lab (Prospero Linden’s rez day is August 6, 2007), and it’s now been just about a year since I submitted my resignation letter to Vanderbilt, officially ending my career as a professor of Physics and Astronomy. It had been a long road; I’d been in grad school at Caltech from 1990-1996, a post-doc at LBNL with the Supernova Cosmology Project from 1996 to 2001, and a professor at Vanderbilt from September, 2001 to June, 2007. I had dedicated my life, years of schooling and work thereafter, to this career. Once, upon meeting the chair of the department of Harvey Mudd (my college) at an American Astronomical Society meeting, he described me as “one of Harvey Mudd’s successes”… for, as many post-docs will tell you, it’s very difficult to get that tenure-track faculty position. But, as I told people many times, even though “most” pre-tenure people who actually put themselves up for tenure end up getting it, pre-tenure is hardly a cake walk.

I left. I jumped ship entirely– and in this field, it may well make it impossible for me to go back. Because there are so many more people than positions, any college that is hiring will be able to hire truly excellent people who never left, who don’t have a gap in their resume. Now I’m working as a computer engineer, trying to help build and maintain the metaverse. Some have said to me (including a professor of astronomy from Caltech) that I may well be doing more for Astronomy than many in tenure track positions– for, after all, Tim Berners-Lee, and Larry Page and Sergey Brin, each did more for Astronomy (even though they weren’t thinking about Astronomy when they did it) than the vast majority of lifelong astronomy teachers and researchers. Who knows.

But, back to the original question. Do I miss it? The answer is an emphatic yes, and an emphatic no. What else would you expect from me?

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Public astronomy talk in Second Life, “Kepler, Newton, and Einstein: ‘Wrong’ Theories and the Progress of Science”

Posted on June 11th, 2008 — permalink

I’ll be giving this talk in Second Life tomorrow (Thursday) at 10AM PDT (in-world time). This talk was originally scheduled for last Friday, but Second Life was having serious problems at the time as a result of networking problems from our upstream ISP.

The talk will be part of the Dr. Knop Talks Astronomy series hosted by MICA. It will be at the Galaxy Dome in Spaceport Bravo.

Remember, basic Second Life accounts are free, as is the client software!

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Technical talk on Dark Energy and Vacuum Fluctuations in Second Life this Friday

Posted on May 8th, 2008 — permalink

In addition to the popular-level astronomy talks I’ve started doing as part of MICA, there will also be regular “journal clubs.” This is something you’ll see in physics and astronomy departments sometimes: people take an interesting paper from the recent literature (really, from preprints nowadays), and lead a discussion about it with their colleagues. It’s one way of trying to keep up with some of what’s going on in the literature, and it’s also a way that one scientist can share his particular area of interest with his immediate colleagues.

This Friday, George Djorgovski will be leading a journal club in Second Life at 8AM SLT (pactific time) on the paper Dark Energy from Vacuum Fluctuations by Djorgovski and Gurzadyan. Note that while in this case, the author of the paper is talking about his own paper, that’s not always the case. In journal clubs I’ve been too, sometimes people talk about their own work, and sometimes they talk about other interesting papers from the literature. For instance, when I was at Vanderbilt and still working with the Supernova Cosmology Project (which used optical and infrared astronomical data), I gave a journal club about the WMAP 3-year results — very releavant to cosmology and my work, but not something in which I was involved.

The journal club will be where all of the MICA meetings currently happen, at the ISM Workshop in Spaceport Bravo.

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Popular Astronomy Talk in Second Life : The Death of Stars (2008-May-02)

Posted on April 28th, 2008 — permalink

I’m going to be giving my second “Dr. Knop Talks Astronomy” popular talk in Second Life as part of the fledgling Meta Institute for Computational Astrophysics.

The talk will be at The Galaxy Dome in Spaceport Bravo, this Friday (May 2) at 8AM pacific time (which is the same as in-world time in Second Life).

Drop by if you’re interested! Here’s the longer description of the talk:

In Fire and In Ice : The Death of Stars

Stars live for millions or billions of years, but they don’t liveforever. When a star reaches the end of its lifetime, spectactular fireworks can result. In this popular talk for interested layman, Dr. Knop will outline what it is that keeps a star together during its lifetime, and what happens to stars of various different sizes when that process finally breaks down. He’ll talk about the ejection of planetary nebulae, the cooling of white dwarves, and the most spectacular of stellar events, supernovae.

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Is the Large Hadronic Collider going to end the world by making black holes or strangelets?

Posted on April 11th, 2008 — permalink

No.

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Dr. Knop Talks Astronomy

Posted on April 3rd, 2008 — permalink

The Meta Institute for Computational Astrophysics is a new venture being spearheaded by Piet Hut, also known as Pema Pera in Second Life. Piet and collaborators have already done some actual scientfic collaboration a virutal world, through Qwaq. However, he— and others, to the point that I can start using the pronoune “we”— are starting to do more in Second Life in an attempt both to bring in more astronomers, professional and amateur, as well as interested community members. Activities are going to include a regular journal club, as well as a monthly outreach talk at the popular level. I will write more about MICA later.

Right now, though, I want to (at the last minute) publicize that I will be giving tomorrow’s in-world popular talk. I’ll be talking on the title “The Power of the Dark Side: How Dark Matter and Dark Energy dominate our Universe”. This talk will be in The Galaxy Dome in the ISM’s Spaceport Bravo. This is going to be a version of a talk that I’ve given before, last Spring when I was still at Vanderbilt and going around giving AAS Seyfert Shapley Lectures. (I think I gave five of those last year.) The talk will be in-world using Second Life Voice, and will be at a level accessible to all (although I always do try to challenge your minds when I give these sorts of talks).

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Five Great Science Education Places in Second Life

Posted on March 17th, 2008 — permalink

I originally wrote this for Second Opinion, Linden Lab’s internal newsletter. It was going to appear as the “Fab Five”… in what turned out to be the issue after the last issue. Oops. Since it never saw light of day there, I figured I’d post it here.

It’s been a number of months since I wrote this. Were I doing it now, there may be some other sites I would have been tempted to include. In particular, the weekly Science Friday broadcasts are something not to be missed. The in-world broadcats, complete with the lively discussions we have in text while listening and the occasional question from a Second Life avatar read on-air happen at the Science Friday Island.

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Science Debate 2008

Posted on December 27th, 2007 — permalink

Sheril and Chris over at The Intersection, along with others, have been beating the drum for “ScienceDebate2008″ for some time now. The basic idea is that we should get the various Presidential candidates together and get them to explicitly address and debate science and science-policy issues. Lots and lots of bloggers have weighed in on this, so don’t expect me to link to them all; I’ll just arbitrarily pick out one post that I liked from Janet Stemwedel and link to that.

Here is my reason for thinking this is a good idea: to reduce the “blank slate” effect that allows people to make bad choices. Although there is this stereotype promulgated by many that scientists (at least of the academic sort) are all flaming liberals pre-biased against the Republicans, that’s not true. The fact is that scientists come from a wide variety of political backgrounds. With a caveat regarding the increasing prominence of creationism in our politics, and also caveats regarding the kinds of things Stephen Pinker wrote about in The Blank Slate, it’s possible to be an exceptional scientist while holding a wide diversity of political views. Mind you, most scientists will believe that any rational person will come to the same conclusion that they have, because scientists tend to be like that. (”I’m really smart, therefore anybody really smart will agree with me.”) But science doesn’t tell us the right division for market forces versus government intervention, it doesn’t tell us about the morality of wealth redistribution versus individual empowerment, etc.

However, the fact that politicians so rarely address science– other than spouting the usual rah-rah “we want to support innovation and high-tech jobs” kind of stuff in sound bytes– allows scientists to project whatever they want to see on the candidate they would choose for other reasons. Mind you, this transcends science. I remember in 2000 watching some people project potential anti-Microsoft-Monopoly potentials on Bush, which is of course a joke. I’ve also seen people project libertarianism on Nader. And so forth.

The fact that politicians so rarely address science allows scientists to vote for politicians who will be disasters for science without realizing what they’re doing. To my point of view, a science debate wouldn’t so much be an actual debate, where issues are hashed out, as a place where politicians were really forced to put enough of their cards on the table that it would be harder for us to kid ourselves in the way that we kidded ourselves in 2000. (Presumably scientists who voted for Bush didn’t believe he would be the disaster for science that he has turned out to be.) I like Janet’s ideas– let’s see who they ask, and what kind of things they say. Let’s find out who really understands something about science, and also understands that they don’t really understand science… and let’s find out where they’re going to be going to get scientific input– or, as in the case of Bush, “support”– for their policies.

There is, of course, one candidate who’s views on science are unambiguous. That would be Huckabee the Creationist, who has come forward with a clear declaration of ignoramusitude. Other than him, though, we may be kidding ourselves regarding Democrats and Republicans alike when we think that any given candidate whom we prefer for other reasons will be better than the mess we’ve got right now. Let’s try to get them talking about it as best possible. Even given the fact that debates are PR-soundbyte prepackaged shams, which soundbytes candidates choose will be useful information.

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