black holes always liven things up

So in a really brief summary for any reader as confused as I am about astrophysics at the moment: The Schartzchild metric is metric derived from general relativity to describe objects falling radially into black holes. I won't try to write it here because it involves a lot of symbols that won't mean anything unless I spend an hour explaining them, and I'm sure it's on good old Wikipedia. So anyway, you can plug the coefficients of the Schartzchild metric into the general equation for a geodesic (describing the shortest path between two points in curved/non-Euclidean space), which is this unpleasant monstrous equation summed over multiple partial derivatives (but which thankfully simplifies for black holes because objects only move radially and not in the other spherical directions so the derivatives in those directions vanish). Anyway, so you can plug all this junk in (well theoretically you could; I'm not very good at it yet, which is unfortunate given our exam next Thursday). Once you do this you can write an equation for conservation of energy, and you can solve for the proper time, or the time measured by the falling object. This proper time is a defined equation that has its final value when the object falls completely into the black hole.

However, the interesting point of all of this math mumbo jumbo I'm talking about is that there are singularities in the coordinate time, or the time measured by things beyond the Schartzchild radius of the black hole. You get singularities because the integral used to solve for time has (r-Rs) in the denominator, where Rs is the Schwartzchild radius and r is the perceived radius of the falling object. Thus when r reaches Rs, you get the observer as seeing the object falling for infinite time.

Okay, while that is cool, that's not my main point here. My main point is that it's kind of sad actually to learn about this math. I read about this effect first when I was in sixth grade or so (I wasn't quite your normal sixth grader, I think, though I really tried for a while to appear dumb and wore way too much makeup). And I think the reason I really liked it, and all of the other astrophysics stuff I read from the age of eight onwards, was that it was, well trippy. I heard someone talking in the lounge at my dorm the other day. He said string theory sounded like someone on acid. He imitated the person by saying "what if everything is made of little tiny strings... woah" and the way he said it really did make it sound a bit like one of those things that people on LSD think are brilliant that everyone else thinks are crazy. And I think that's always why I've liked astrophysics, because it was so out there, because it bended my thoughts at every turn.

And it turns out that while I do like actually learning the math for these things that have amazed me for over half my life, in a way it's kind of sad. I'm the kind of person that would rather think about things that actually do the experiment, which I think differentiates me at this school (except maybe all the math majors are like that, but they're too far gone I think in their topologies). When I actually have to do the math (besides feeling upset at having to face my woeful failures in basic algebra), I feel like I'm kind of losing something, the clarity of the acid trip maybe, the "woah, dude, that's gnarly" aspect of it all.

So it's nice I guess to think that the reason the proper time and the coordinate time are different at the vanguard of the black hole is an integral denominator approaching zero, but it's not quite as nice as thinking that it's some crazy bent up quality of time itself that I can make up in my head because I don't know enough to make realistic predictions. I like my creative astrophysics ideas. I love the ideas a lot. It's just not quite so fun when I have to calculate derivatives.

Anyway, it doesn't matter I suppose because in the end I chose what I was best at (biology) and abandoned what interested me most in that acid-trip way. And while I was sad for a while, I don't regret it at all now. Because I can always sit around in my living room thinking about things stretching in black holes, but I can't really think about the psychedelic awesomeness of AMPA receptor endocytosis during depotentiation, and that's something I actually enjoy figuring out in a lab. So I think I'm doing the right thing.

But seriously, tiny vibrating strings whose curled-up radius determines the properties of the particles we actually "see" (in cloud chambers anyway)?

Gnarly, dude.

alan guth's sense of humor

In the frame of the Earth, all the objects (the elevator, the man, and the
groceries) are accelerating downward under the force of gravity. But in the frame
of the elevator, everything appears weightless. (Well, all is weightless until the big
crunch occurs in the building’s basement — but remember, this in only a thought
experiment. No living creatures were harmed in the writing of this paragraph.) -From Alan Guth's lecture notes

While I am currently hopelessly confused at deriving metrics for non-Euclidean spaces obeying general relativity, at least I get thrown a bone every once in a while. Don't worry! Nobody was hurt! They repeat this elevator thought experiment in every class involving general relativity in the universe, I think. But nobody was ever harmed!

:-P

(later note- found another one):
One further simplification is known as the Einstein summation
convention. This is no doubt Einstein’s most important contribution to ecology,
saving barrels of ink and tons of paper each year. The convention stipulates that
whenever an index is repeated, it is automatically summed over the standard range.

Haha. Einstein's contribution to ecology. Obviously his greatest talent in life.

language acquisition

As annoyed as I am getting with all of these papers I have to read about children's performance on verb raising of finite main clause verbs in German and negation movement in French etc etc, I really do appreciate that one of the largest miracles of human existence, almost as baffling as life itself, is language acquisition. It's such a miracle that a baby with only the rudimentary congenital genetic capacity for language manages to take sounds and through some elusive devices including calculation of distributional frequencies, prosodic word boundaries, and phonotactic constraints, determine what a word is and somehow learn the representational content of that word. I mean, first of all obtaining a lexicon is so amazing... I think the first time a child says "ma ma" or whatever his first utterance is, is perhaps the greatest miracle of all cognition. How has this little child with such an underdeveloped cognitive faculty manage to do something so mathematically amazing, something we can't even get computers to do, just by listening to disorganized input?

And then later, for children to go on and somehow learn to set their languages parameters (for example the horrid papers about German and French acquisition show that toddlers have an awareness of syntactical functional categories (inflection, complementizers), head movement (like with finite V2 verbs or negation), and the difference between finite verbs and infinitives (apparent even within the optional infinite stage as the child manages to place the verb correctly in the V2 languages, even if he is conjugating incorrectly by using an infinitive in a main clause). I mean, most of us learn how to talk without really ever understanding linguistics. It's so amazing how naturally it comes, how children have this unspoken awareness of complicated conventions that I can't even seem to learn now for my linguistics midterm.

I honestly don't even like linguistics that much (although I do enjoy syntax and I like thinking about acquisition), but one cannot deny how amazing it is that we have a language at all, that it somehow erupted from our genetic nature. No other animal is anywhere near having the language complexity that we have (the closest is like those monkeys with different calls that I rambled on about a year ago in this blog, and they can't really talk to each other, just scream "jaguar" and the like).

Amazing. Life continues to amaze me. Maybe that's why, despite all of my attempts at becoming a physicist, I ended up right back in biology.

state dependent learning

It was actually admitted by our neurophysiology TA that it is better to smoke pot while studying (creating a drug-altered effect) and then to smoke right before taking the test than to not smoke at all. I guess drug altered states cause really strong state-dependent learning, and recall is way enhanced if you put your brain in the same state again, even- get this- even if the drug-altered state is detrimental to memory formation. We haven't quite learned the mechanism for the detrimental drugs, but I find it interesting.

Of course, if you're smoking pot there's the challenge of getting yourself to really focus on studying or taking the test. I am told that while it's easy to really focus on one thing while high and kind of tune everything else out, one is also easily distracted by other interesting things.

I'm not planning on trying it. But it is interesting.

a quote that could be taken out of context...

"It's always much better to react with yourself than with someone else, even if they're associated with you."
-organic chemistry teaching assistant

Ha ha. He was talking about intra-molecular reactions being more energetically favorable, but it sounded kind of funny if you weren't paying attention to context.

a funny thing about alcohol...

So because memory recall for some strange reason regenerates hippocampile lability (ie it requires protein synthesis in the hippocampus, which is really weird because consolidated memories aren't hippocampus-dependent and are stored elsewhere in the brain), you can do some funny things.

Imagine the scenario: you have a test coming up on Monday. One week before, you study really hard. Between Monday and Friday the memory begins to consolidate. You decide on Friday that you worked hard enough on Monday, so you just review the material briefly in the afternoon. That night you go to a party and get really drunk.

The interesting thing is that if you do this, you're liable to lose your entire memory of everything you studied, not just your review of it but the original memory as well. This is because when you recall the memory on Friday, you make it labile again. Alcohol is known to mess with forming memories in the hippocampus, so it can mess with reconsolidation of pre-formed memories. Essentially, if all you did was study on Monday and then got drunk Friday, you'd be better off than if you attempted to be somewhat responsible by reviewing before partying.

Wholesome message of the day: get drunk now, review later.

Or, my preferred and personal message: just don't get drunk.

obama of course

It's kind of thrilling to be joining the masses blogging about this right now. Not that my words obvoiusly hold any sway, but it's somewhere to put them.

Yes, I like Obama. Yes, I think he's doing a much better job than Bush (although I always thought Bush was trying to do the right thing). Granted he hasn't been as rigid on healthcare reform as he should have been.

He's been in office for eight months, and despite all his efforts it seems he hasn't accomplished that much peacekeeping stuff. He's tried, yes. I do believe the motives are there. But the results? Lots of people have motives to make the world a better place. If nobel peace prizes were awarded for motives, every other person would have one stashed in the closet.

So I guess I agree with people that say the nobel prize committee folks jumped on the bandwagon with this one. There are people more deserving than Obama. There was even contention when Gore got the prize, and it was apparent that he'd at least done more actual work than Obama has.

So yeah. Interesting idea, giving him the prize, but should have been a few years pending.

Not that I don't like Obama. To my parents great chagrin, I really do.

the only thing the human brain can't understand:

Obviously itself. We know so much about the physiology of every other organ in our body. We know so much about the first three minutes of the universe when everything was radiation dominated and atoms couldn't form. We know more about the nature of spacetime and cosmology in general than we know about our own minds (brains?).

On a good day, that's exciting to me. There's so much left undiscovered in the field of neuroscience, and that unappreciative gap between cognitive science and neuroscience. On a bad day (like today), that just seems overwhelming. I feel like we'll never understand all of these mechanisms in our brains. It's not like something in physics that takes a sudden insight to all fall into place. Everything's complicated in neuroscience. So many things are impossible to understand, and so many aspects are impossible to model experimentally due to the complexity of everyday life. It's crazy.

An example of this is the occlusion of learning by previous learning. I pick this example because I feel like it has happened to me, although I am assured by my neuroscience professor that such a thing is impossible (it would require the saturation of every synapse in my hippocampi). However, I feel like every synapse in my hippcampi has reached its excitatory maximum, its information threshold. In such a case, further learning is occluded. Why? We don't really know. One way to occlude learning is previous maximum phosphorylation in the postsynaptic spine (since phosphorylation drives so many processes involved in potentiation, saturating the phosphorylation by inhibited phosphotases for instance yields a maxed out post synaptic density). But that's only one way. We have no idea what other mechanisms may be involved, or what role such saturation has to play in normal behavior (although I am convinced it is the reason I can stuff no more information into my brain before my test tomorrow and my test Wednesday). And there's no promising way to experimentally figure that out in the near future.

That's just one mechanism of a million in the study of long-term potentiation, and long-term potentiation is just one effect of millions in the study of the brain. Hopeless.

On a side note, the tree outside my window has turned a beautiful rustic red (if I remember correctly this is because the chlorophyll that reflects light of the green wavelength dies out in the fall, leaving other photopigments to control the coloration of the leaf as it slowly dies and falls to earth). The tree next to it is still largely a hearty green, but the very peripheral edges next to the red tree are also turning red. It looks as if the red tree has a communicable disease that is slowly spreading to the surrounding foliage.

How interesting, to think of beauty as a communicable disease. Or is it death, primarily?