Archive for the 'Second Life Events' category

Astronomy talk in Second Life : Solving the 3-Body Problem


I'll be giving a talk in Second Life on Saturday at 10AM SLT (Noon CDT, 17:00 UT). This is part of the regular series Dr. Knop Talks Astronomy.

Double and Triple Stars: Solving the 3-Body Problem

If you look at the stars in the night sky, you discover that a very large fraction of them are not isolated, but are in fact in binary star systems, or even in larger groups. Using Newton's gravity, we are able to perfectly solve for the orbits of a system involving just two bodies, but it's impossible to analytically solve it for more. In this talk, I'll describe why we care-- not only in trinary star systems, but three-body interactions also matter in rich clusters. I'll describe how we're able to solve the 3-Body problem and figure out the orbits of stars in such system, and give a demonstration of a working computer that actually solves the system in Second Life, right before your eyes....

The talk will be at the MICA Large Amphitheater in Second Life. Remember, a Second Life account is free!

In related news, I've now uploaded the slides to all of my previous talks to the MICA website.

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"The Stars in a Galaxy" -- talk Saturday at 10AM PDT / 17:00 UT in Second Life

I'll be giving the latest installment of my the regular talk series "Dr. Knop Talks Astronomy" (usually, but not always, given by me) in Second Life tomorrow (Saturday) morning. This time I'll be talking about the stars that make up a galaxy:

We now know that most of the mass of a typical galaxy is Dark Matter. But, when you look at an image of a galaxy in optical or near-infrared light, the light you're seeing comes from the stars. It turns out, however, that the stars that are responsible for most of the light you see are not representative! Most of the stars in a galaxy, and indeed most of the stellar mass of a galaxy, aren't the ones emitting the light that you see in a typical image. In this talk, I'll describe what we know about the kinds of stars that one finds in a typical galaxy. How typical is the Sun? What are the stars that we're mostly seeing when we look at a galaxy? And what makes up most of the stars in a galaxy?

Drop by and see us in the StellaNova Large Amphitheater in Second Life. Second Life accounts are free; you can join at the registration portal offered by the SciLands.

This talk will use Second Life Voice.

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This morning in Second Life : Comets Crashing Into Jupiter

I'll be giving a public-outreach astronomy talk as part of MICA this morning at 10AM PDT in Second Life entitled "Comets Crashing Into Jupiter".


A few weeks ago, an amateur astronomer spotted a scar on Jupiter, which was later confirmed to be the result of an impact of a comet fragment with the giant planet. This is not the first time we've observed comets smacking into Jupiter; in 1994, comet Shoemaker-Levy 9 collided with Jupiter after having been torn into several fragmets by an earlier pass with the planet, leaving scars on Jupiter over the course of a week. In this talk, I'll describe the gravitational interactions that lead to these comet collisions, as well as what we may be able to learn about Jupiter as a result of these collisions.

To keep track of what popular talks are upcoming in MICA, see our Upcoming Public Events Page.

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"Superluminal Jets in Quasars" -- Saturday in Second Life, 10AM PDT

Tomorrow (Saturday) in Second Life I'll be giving a public talk about the relativistic jets we see emerging from the cores of active galactic nuclei, and in particular I'll explain how it can be that some of them are apparently moving faster than the speed of light...!

The talk will be at the MICA Large Ampitheater in Second Life at 10AM PDT (Noon CDT, 1PM EDT).  Remember, a Second Life account is free! You can join via the SciLands registration portal-- if you do, that will take you to the SciLands orientation experience.  (StellaNova, the in-world home of MICA, is part of the SciLands.)

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Actors Backstage


This is a snapshot I took during a rehearsal for Avatar Repertory Theater's upcoming performance "Shakespeare at the Pavillion" (Saturday and Sunday, 4PM PDT in the San Diego City sim in Second Life). A bunch of us were backstage, costumed up for various upcoming scenes. It looks very much like a classic "backstage" such as you might find in a real-life theater; lots of people, standing around, dressed up in all manner of wacky costumes.

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Shakepseare & Relativity in-world this weekend

I'm going to be busy this weekend with a public outreach talk and some Shakespeare performances.

Saturday morning at 10AM SLT/PDT, I'll be giving a talk entitled Time dilation and simultaneity in Special Relativity. This is part of the regular "Dr. Knop Talks Astronomy" public-outreach talk series given by MICA. If you're curious about just why it is that moving clocks run slow in special relativity, drop by and I'll explain it. You don't need any math to understand the basics; with just early high-school algebra (the Pythagorean Theorem), you can even understand the equation for how slow clocks run. The talk will be at the MICA Large Amphitheater (StellaNova (213, 210, 32)).

Then, Saturday and Sunday from 4PM-5PM, Avatar Repertory Theater will be performing scenes from several Shakespeare plays in our "Shakespeare at the Pavilion" performance, in association with the San Diego City sim. We'll do scenes from Twelfth Night, Julius Caesar, Hamlet, As You Like It, and A Midsummer Night's Dream. See the A.R.T. site for more information.

I remind everybody that a Second Life account is free. Here is one place you can register for an account— that's the registration portal for the SciLands, a contiguous group of regions of which MICA is a member. That will take you to the SciLands' orientation spot. Both of the events above will use Second Life Voice, but you don't need a microphone or a headset; you'll just need your standard computer speakers to hear what's going on. There are Second Life viewer applications for Linux, MacOs, and Windows.

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When Stars Collide

When I've given talks about colliding galaxies, I always start out by pointing that that the stars within a galaxy basically never collide with each other. This is, of course, an oversimplification....

You may have seen a "scale model" of the Solar System. It gives you a sense of how amazingly spread out things are... especially after you've made the hike to get to Saturn, never mind Uranus, Neptune, or the Kuiper Belt. But you never see a scale model of the nearby stars. Why? because things are even more amazingly spread out. Suppose I wanted to make such a scale model, and, here in Nashville, TN, I used a tennis ball to represent the Sun. To represent the nearest star, α Centauri, I'd need another tennis ball that is in New York City. Stars are really, really far apart from each other. Our galaxy is mostly empty space. (Well, actually it's mostly dark matter, but within the disk of the galaxy, the mass density is more stars than dark matter. And, between the stars, there is interstellar gas, but the density of that gas is much lower than the density of gas in the best vacuum chamber we've built on Earth.)

However, there are places where this isn't strictly true. We see some stars in globular clusters that are more massive than stars that have any business still being around in that globular cluster. (That is, globular cluster stars were all formed 11-13 billion years ago. Stars with higher mass have shorter lifetimes, so any star above a certain mass cutoff isn't seen in a globular cluster.) One very likely explanation for this is that these stars are the result of a merger between two lower-mass stars.

It may also be possible in some very rich young clusters of stars that stars may collide with each other before the cluster disperses. The black hole at the center of our galaxy may very rarely "eat" a star. (No, we haven't seen this happen.)

Last week, Jamie Lombardi of Allegheny college gave a seminar in Second Life as part of the MICA professional seminar series entitled "The Hydrodynamics of Runaway Collisions." At the very beginning of the talk, he had to clarify that he was in fact talking about colliding stars. I give a lot of public-outreach astronomy talks for MICA (a different series, obviously, from the serious of professional seminars), and I have given a couple of talks about colliding galaxies. My own history as an astronomer leads me to think "collisions" to mean "between galaxies"-- and the hydrodynamics, then, must be referring to the gas processes that might, say, feed an AGN.

However, cool things can happen when three stars have a close enough pass that their envelopes start to spill on to each other. Sometimes, two of the stars will merge (while the third one in the collision is ejected). Some of the gas is lost, but much of it stays behind in a more massive star. The timescale for these collisions is short enough that the stars will not evolve appreciably during the collision, so this may well be a way that you can make a star that's more massive than what would naturally form out of star formation nowadays— especially if you can chain together several collisions. What Jamie was talking about, of course, probably only applies in very young, very rich clusters. The globular clusters in our Galaxy today are too old to have the kind of massive stars that Jamie was focusing on in his talk, and most of the star forming clusters nowadays have several orders of magnitude fewer stars than globular clusters do. But, globular clusters were once young....

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This Saturday at 10AM PDT in SL : "How We Know Dark Matter Exists"

As part of my regular Dr. Knop Talks Astronomy series of public astronomy lectures in Second Life, this coming Saturday I'll be talking about how we know that Dark Matter really exists.

The talk will be at the Large Ampitheater on StellaNova. Note that a Second Life account is completely free! You can register for an account here. This is the "SciLands" entry portal, which will put you at the SciLands own orientation island. (StellaNova, the sim of MICA, is part of the SciLands.)

Here's a description of the talk:

Modern cosmology tells us that the majority of the Universe is made up of stuff whose nature is largely unknown to us. Two thirds of it is Dark Energy; most of the rest is Dark Matter, the subject of this talk. Dark Matter interacts with normal matter through gravity, but otherwise it interacts hardly at all. Yet, we have very high confidence that this mysterious Dark Matter really does exist. Because it doesn't interact with light, we haven't seen it glowing, nor have we observed it absorbing background light as we've seen with dust clouds. All of the evidence we have for Dark Matter comes from its gravitational interaction with other matter, and with light. Yet, this evidence is extremely compelling. In this talk, I will attempt to convince you that there is no reasonable doubt that Dark Matter exists.

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Popular Astronomy Talk in Second Life, Friday 8AM PDT (11AM EDT)

I'll be giving a talk entitled: "We Are Starstuff: the Cosmic Origins of the Chemical Elements" as a part of the MICA public talks series. The talk will be at the Galaxy Dome in Spaceport Bravo.

Remember, a Second Life account is free!

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"Planets Around Other Stars" -- talk in Second Life this Friday at 8am PDT

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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