Ok, legitimate post! Yay break!
Today I present the only part of astronomy that I've followed religiously through my humanities phase: space weather!
What is space weather? It's the interactions between the Sun (and what it throws off) and the Earth (or other planets, but we're egocentric). Aurorae are the most famous visual manifestation of space weather, but there's a lot more to it. To understand the phenomena, we should start with a basic understanding of the composition of the Sun and our little home rock...
The Sun: this site (click here) gives a good, if slightly technical, description of the Sun's layers. As an overview, the Sun is essentially one vast ball of hydrogen gas (~91% H atoms), which is so immensely large that the hydrogen in the core gets crushed under its own "weight" into helium via nuclear fusion.* However, it's also got layers, like the Earth does. There's a large convective layer that mixes the extremely hot gas around the Sun's interior, and this creates electromagnetic currents. These currents run like strands through certain localities; they are not consistent throughout the Sun -- remember this, it's is important later. The outermost layer spins like a skin on a spherical pudding (insert typical physicist joke on spherical objects here). Much like the Earth's crust, it spins at a different speed from the lower layers; however, unlike the Earth's crust, the section near the equator spins once every 25 days, while the poles rotate once every 36 days. This causes something like friction at the regions where the speeds differ.
I'll carry on with the Earth next time; that's right, I'm leaving you with a cliff-hanger! 'Til next time, redshifted readers! And merry Christmas!
*N.B.: I put weight in quotes here, because weight and mass aren't the same thing. To use the age-old example, you weigh about 1/6 of your normal Earth weight on the Moon, but you certainly haven't shrunk -- in other words, your weight has changed but your mass hasn't. This is a function of the mass of the object you're standing on (or in, in the case of the hydrogen atoms in the Sun). In space, this becomes important, since gravity has a different magnitude for every star, planet, etc.
Monday, December 24, 2012
Wednesday, December 19, 2012
Frustration with the Red Planet
Finals are, in fact, over, so I can re-prioritize this. The first thing I did in catching up on the astronomy news I missed in the last week or two was checking up on the Mars rover.
I didn't want to sound like a spoiled child. But come on, there's been no real data released since that measly little announcement at the conference at the beginning of December! Curiosity's been "investigating" rocks, taking photos, sniffing the air, and digging around for over five months. It would be really nice to have heard more than "we didn't expect the wind to blow in this direction" and "oh look, more chlorates."
Short post tonight, just venting the frustration. I know they have to sift their own data for some time, but after this long I would've expected we'd at least have whatever new info they've gleaned from the first on-the-ground photos.
I didn't want to sound like a spoiled child. But come on, there's been no real data released since that measly little announcement at the conference at the beginning of December! Curiosity's been "investigating" rocks, taking photos, sniffing the air, and digging around for over five months. It would be really nice to have heard more than "we didn't expect the wind to blow in this direction" and "oh look, more chlorates."
Short post tonight, just venting the frustration. I know they have to sift their own data for some time, but after this long I would've expected we'd at least have whatever new info they've gleaned from the first on-the-ground photos.
Monday, December 10, 2012
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.
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.
Monday, December 3, 2012
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.
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.
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