“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.
September 4th, 2009 at 7:37 pm
There was a great talk at the AAS 2004 January meeting about our Universe within 5-10 parsecs or so. The number of O stars? Zero. B stars? Zero. A stars? Four. Yet there are many hundreds of stars total in that volume. It’s pretty interesting!
You’ll do a great job with this talk, Rob; go have fun with it!
September 4th, 2009 at 8:22 pm
Ethan — was that the talk that Todd Henry gave, where he started out playing the theme from “Mission Impossible” and calling out members of the team by “detecting” stars and having them stand up holding a card about them? And then he proceeded to fill a fishbowl with balls representing the stars? Yes, that was a great talk. (I heard some grey beards waggling afterwards about how they’re there to hear serious talks, not that kind of goofing around. I hope I never waggle when I have a grey beard.)
I just did the statistics of stars within 10pc from the Hipparcos Catalog, and, yep, saw the numbers
Esp. considering that M dwarfs and white dwarfs will be undercounted.
September 4th, 2009 at 11:24 pm
That was definitely the talk that Todd Henry gave! It’s kind of funny, because the big, bright stars that I think of (knowing very little about stars) — Sirius, Rigel, Vega, Arcturus — are either two of those four A stars nearby (Sirius and Vega), or are super bright and super far away!
Yes, it was a memorable talk, clearly, if I’m talking about it and it’s more than 5 years later! It was a striking example of how poor a job light does, even for luminous baryonic matter, of tracing the underlying matter.