Where is Aaron?

Continuing the where is theme… I am not gone, but graduate school has taken over my life. I had a ton of nice SA goals for the summer but almost none were accomplished thanks to the unexpected demand of graduate research during the summer (I foolishly thought I’d have summer to myself, causing the graduate gods to laugh and smite me). It’s clear I can’t contribute at the level that SA needs and deserves.

So to the rescue are Michael, Doug and Travis. They will keep things running and add some new ideas of their own. I’ll try to contribute where I can, in between weekend benders of coffee and red bull.

Rebekah is still here, but she has been in another state most of the summer experiencing a fabulous surge in her professional acting/singing/dancing career. She even has achieved qualification for the much sought after actor’s equity card. Congrats to her!

Here is a glimpse into some of the stuff I’m doing at Tufts. The symposium is next week and I’ll post a report. Astronomy education research is a relatively immature field with lots of varying interests and philosophies.

Where are the forums?

The forums haven’t gone anywhere — they are right here, from which I quote:

We are going to decommission this discussion area. We are doing it for a few reasons. One, there just isn’t that much activity here and we don’t really use it for much on an official basis. Two, we’d like to start opening up comments on the blog posts. People are very used to that form of interaction. Three, we’d like you to consider writing an occasional blog post for the blog! If you register and ask us, we’ll promote you to a Contributor. You can write blog posts and if we like ‘em, we’ll put them on the blog.

There are tons of great astronomy discussion forums on the web, such as the Bad Astronomy and Universe Today Forum. Feel free to suggest others in the comments. We’d like to bring discussion here at Slacker Astronomy back into the blog, so please don’t be afraid to get discussions going in the comments of blog posts.

Welcome Brits!

We’ve gotten some emails from over the pond due to a Slacker Astronomy mention over at the BBC. Webscape author Kate Russell writes:

What makes this site such a good watch, or listen, or read, is that as well as being jokey and enthusiastic, there is a real depth of knowledge.

Thanks, Kate!

Energy Part 2

A while back I wrote a post about energy.

Here’s another example of energy that I think is interesting. When you take an automobile which is initially at rest and get it going 55 miles per hour, it gains kinetic energy. KE = (1/2)mv^2. So a car that weighs 2000 lbs. (900 kg) going 55 mpg (25 m/s) would have KE=(1/2)(900)(625)=280 kJ (kilo-joules) of energy. That energy comes at the expense of gasoline — chemical energy — exactly 281 kJ’s worth. Excluding all the messiness of friction and air resistance and such, we used exactly the same amount of chemical energy as we gained in kinetic energy. So it doesn’t matter if you use gasoline, hydrogren, electricity or biodiesel, it takes 281 kJ of energy to get your car going 55 mph.

Continue reading Energy Part 2…

Low-mass “First Stars”?

The BBC reports: Dark matter clues in oldest stars:

“In cold dark matter the particles move very slowly; in warm dark matter they move very quickly,” he explained.

“We found that if the dark matter consists of these fast moving particles, then the first stars form in very long, thin filaments…Some of the stars that formed within the filaments would have had a relatively low mass, which is of interest to astronomers as they have a long lifespan and could still survive today.

Dr Theuns added: “In stark contrast, what happens in (the simulation with) cold dark matter is very, very different. Here, the first stars formed in little lumps of dark matter, and just one star per dark matter lump. And these stars are probably very massive as well: 100 solar masses. Because these stars are so massive, they die very quickly; so you wouldn’t find such stars in the Milky Way today,” he said.

Everything I’ve read about the “1st stars” (or Population III stars) is that they would have been very massive because they lack metals (elements heavier than Helium). The stars that followed them (Pop. II and Pop. I) had access to heavier elements created by the supernovae of the Pop. III stars and evolved differently as a result.

What’s important here, as I read it, is that we have a “1st stars” option which creates low-mass stars that could still exist today. So finding such stars could tell us something about dark matter.

SG 7.0: Interview with Timothy Ferris

Finally, another exciting podcast installment from the slackers! This episode features chit-chat with Travis, Doug and Michael and an interview with Timothy Ferris.

Listen now (MP3, 48:06, 33.2 MB)

The show notes are on the Slackerpedia Galactica.

Download

New Look

I’ve been playing with the look and organization of the blog a bit. Please let me know what you think! It’s a bit of a work in progress but some attention has been long overdue.

And really, in all seriousness, we truly do have a new show almost all set to go!

(Travis? Travis, can you hear me?)

Set your Tivo: Seeing In The Dark

Don’t forget to watch Seeing in the Dark on PBS on September 19th, 2007. If you missed it, get it on DVD, hopefully in HD.

I was lucky enough to be part of this, so I am biased, but I think it is very well done. The photography is beautiful, the music (by Mark Knopfler) excellent and the subject matter really quite interesting, even, I’ve seen, to people who don’t know anything about astronomy.
More into at http://www.seeinginthedark.org/