Kids in Astronomy

I was invited by a friend recently to hold an astronomy night for some kids. Now, I've never been known as a creative person, so where education types and elder sisters would be going nuts with tubes of glitter and marshmallows, I draw a blank. I know the things that make me excited about space, but the idea of that row of prematurely-jaded faces gives me the heebie-jeebies. I didn't understand those kids when I was their age; I understand them even less now.

So, I think about how I was when I was a pre-teen. The thing I wanted most was to have my intellect be considered the equal of any adult's. Just because I was in a pint-sized body, I reasoned, didn't mean that I couldn't grasp the concepts of quantum entanglement or multiple dimensions. One memory is particularly distinct. I was sitting on my bed, surrounded by my intro-level astronomy books. They were basically glorified picture-books, all bright colours and little text. I had a sheet of paper, with childish scrawling trying to piece together bits on black holes from each book. I was so frustrated. How could these authors introduce topics like singularities, and then just move on without explaining how they work, what we've seen, what we've calculated? It would be like killing Scheherazade on the 50th night. What's the point?

The bottom line is simple: children aren't stupid, they are untaught. A plethora of studies have shown that in so many topics, kids command flexibility and insight of mind that adults spend the rest of their lives trying to recreate. If anyone should be being fed our most complicated problems, it should be them. They have curiosity, intelligence, and imagination, and are unfettered by preconceptions about the so-called "laws" of the Universe.

So what am I going to tell these kids? I'm going to think of the "big concepts" that are supposed to be too much for their minds, and explain as much information as I can about them. I'm going to respect their brains, treat them as capable thinkers instead of cutesy factoid ingesters. Then I'm going to let them talk about it, stew in it, come up with solutions I bet would widen the eyes of any physicist. If we want to rehabilitate our nation's science education, this is how we need to start.

Brown Dwarves

I always feel like saying that is a slur, somehow...anyway, short post tonight (heading towards finals...who thought it was a good idea to hold regular exams a week before finals? Just cover the material in the final!) on brown dwarves.*

Brown dwarves are small objects that fill the rather broad size gap between planets and stars. Essentially failed stars, they start at around 12-15 Jupiter masses and go up to...well, the size of ignition, about 10% of the Sun's mass.

What's a failed star? It's an object that started collecting gas from a nebula (hydrogen, some helium maybe), and may even have created a disk of swirling material. Unfortunately, for whatever reason, it ran out of gas to accumulate. This means that its total mass was insufficient to crush the hydrogen atoms at its core into each other -- creating helium through nuclear fusion, and consequently kick-starting its life as a star. Instead, it just sits there like a largish ball of matter, quietly wiling away time.

Ok, that's why they're not stars, but what differentiates brown dwarves from rogue planets? Well, dwarves, ironically, are just too big. There are a few other differences, although if you look too closely, you'll find that astronomers are still a little fuzzy on the details.

Firstly, their pseudo-stellar-disk method of formation is similar to that of a star, not a typical planet. Many rogue planets are presumed to have been slingshot from an unstable orbit around a multi-star system. Not so with brown dwarves.

Secondly, they are hot gaseous bodies; most of our planets, and the other planets we've found outside our own solar system, are either terrestrial (can be hot or cold) or Jovian, which are typically cold. This is related to where they form: terrestrial bodies form closer to the star, with less chance of capturing or holding onto gases; gas giants form outside the "frost line," where most gases condense to liquids or ices.** Contrary to this, brown dwarves do not give off much light in the visible spectrum, if any, but they emit a good deal in the infrared (IR) spectrum. Compare the images from Jupiter in the IR spectrum here and an image of a brown dwarf binary system here.Other images are more dramatic, but clearly even from a far greater distance, the brown dwarves give off a great deal more infrared radiation.
 
Thirdly, planets differentiate if they're made out of more than one element (go look up diamond exoplanets, pretty awesome). Heavy metals like iron and nickel sink to the core, and lighter elements rise to the surface or atmosphere. Brown dwarves are just a ball of mush. Its gases may have been there since formation, or a small amount of hydrogen fusion may have occurred early in life; physicists are still arguing over the parameters.

So, brown dwarves. They're hard to detect and they make the border fuzzy between what seemed previously to be pretty nailed-down definitions. They aren't stars, and they aren't habitable. We can't quite seem to figure out what they're for, in the grand scheme of things. If I figure it out, I'll let you all know.




*Yes, dwarves; I hate American spelling.
**There are "hot Jupiters" being found by recent exoplanet searches, but the term is relative; they're still quite cold, and they are believed to have migrated inward towards their star from their original orbit outside the frost line.

Google's Interactive Star Map

First real post! I'm on fire...

I was trawling my Twitter feed before bed, and I found this link: http://workshop.chromeexperiments.com/stars/

Go drool for five or ten minutes (or half an hour, whatever) and then come back and read this.

This has to be getting more press SOMEWHERE than what it's getting on the various feeds and sites I follow. While it's not the most in-depth or scale accurate rendition of our stellar neighborhood that could be made, it's still a great tool. It helps bring the concepts of distance and size down to something more easily grasped, which is (to my mind at least) one of the major stumbling blocks people face when learning astronomy.

Numbers scare people; it's easy to become dazed when comparing millions of miles and billions of lightyears, without being able to visualize either one. I was reviewing some of the distances earlier in the year for my astrobiology class, and I sat there for...quite a while, just zooming in and out in my mind between the measures involved in the solar system, galaxy, Local Group, etc. Now, that sense of enormous distance is one of the things that makes me feel most strongly that I'm studying the "right" thing for me, but someone who's dabbling around the edges of astronomy needs something a little more hands-on and a little less terror-inducing. And (as much as I hate to pat Google on the back), I think this app does that admirably.

Which brings me to another thing I think the site does really well: it takes the emptiness out of the Universe. By focusing on i.e., stars everyone has heard of (at least every geek and sci fi fan), it shows where we are situated generally without emphasizing the immense tracts of nothing (or whatever they're calling "nothing" this week) that lie between. The comforting streak of the Milky Way that lies behind each star image reminds you of the scale while situating you firmly in something familiar, our galactic town's local landmarks.

That's enough philosophizing for the night. Til next time,

~The Clumsy Astronomer