Several random questions about physics, biology, math

[theblackkeys]

Alright, just trying to tie up a few loose ends that I encounter in my studies.

1) In a cell, what causes vesicles, vacuoles, and other "stuff" to move in the cytoplasm? I'm looking for the cause of the force that gives them movement. Is it osmotic pressure? Electromagnetic forces?

2) Is race a social construct? Does it have valid scientific usage?

3) I get the impression that some of you (borodog?) here have some sort of theory of abiogenesis in your brain. Explain your ideas to me. I've read the wiki.

4) May be tough to answer given that I haven't studied anything beyond mechanics and electromagnetism. What "causes" gravity to act on one object? Like a hand pushes a cart and makes it move, is there something that interacts with the object to cause the force? Is it just something which we don't have a complete answer to? Is the space warpage a satisfactory answer? Please don't respond with the equation, I know it.

5) Similarly, what causes electric and magnetic forces/fields? I haven't completely finished the course, so perhaps it explains later. But in the first chapter on electric forces/fields, it explains it by saying "it SOMEHOW modifies the properties of space around it". Big lol. How does one electric point charge "know" the other is there?

6) Remember the giant ridiculous OOT thread about jason_t and John Nash, where callmeishmael called everyone idiots for choosing $100 +/- $1, instead of $3 (link someone?)? Well I was wondering WHY game theory gives an absolutely horrible answer to a basic problem.

7) Philosophy is probably the most retarded field of study ever. T/F? No one can even agree on the meanings of important keywords. Also, I don't know why rationality is always assumed. "Emotion", feeling and instinct have done pretty damn well for humans and animals in general. It is basically ignored in philosophy, no? I'm rarely completely rational except when I'm sciencing and [censored].

8) How much of a joke are these majors in uni?
-communications
-sociology
-anthropology (wtf, it should just be lumped in with sociology already)
-women's studies
-whatever ethnic studies (asian, latino, black)

9) Guitar is rad.

[madnak]

Heh. Doubt I can help much, but I'll comment anyhow.

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Alright, just trying to tie up a few loose ends that I encounter in my studies.

1) In a cell, what causes vesicles, vacuoles, and other "stuff" to move in the cytoplasm? I'm looking for the cause of the force that gives them movement. Is it osmotic pressure? Electromagnetic forces?

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Motor proteins and Brownian motion.

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2) Is race a social construct? Does it have valid scientific usage?

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Ugh, strikes me as a red herring. If biological races exist in humans, there are a couple of points to keep in mind about them. First, things like skin color aren't very useful in distinguishing between them. Second, given that isolated populations are a thing of the past, so are races.

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3) I get the impression that some of you (borodog?) here have some sort of theory of abiogenesis in your brain. Explain your ideas to me. I've read the wiki.

4) May be tough to answer given that I haven't studied anything beyond mechanics and electromagnetism. What "causes" gravity to act on one object? Like a hand pushes a cart and makes it move, is there something that interacts with the object to cause the force? Is it just something which we don't have a complete answer to? Is the space warpage a satisfactory answer? Please don't respond with the equation, I know it.

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Based on what I know, fundamental forces are mediated by gauge bosons, and a lot of people think gravity must be similar and be mediated by "gravitons." But nobody has actually been able to "find" gravitons. I think there are different hypotheses about it. Boro and Metric should know.

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5) Similarly, what causes electric and magnetic forces/fields? I haven't completely finished the course, so perhaps it explains later. But in the first chapter on electric forces/fields, it explains it by saying "it SOMEHOW modifies the properties of space around it". Big lol. How does one electric point charge "know" the other is there?

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I've been asking my professors about this, and they've only made things more confusing for me. Apparently the hugely oversimplified model is that electrons "shoot out" photons, which "move" things. That's cutting some corners even from the brief explanation I was given, but those "corners" are pretty wacky so I'll leave those in the know to talk about them if they want.

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6) Remember the giant ridiculous OOT thread about jason_t and John Nash, where callmeishmael called everyone idiots for choosing $100 +/- $1, instead of $3 (link someone?)? Well I was wondering WHY game theory gives an absolutely horrible answer to a basic problem.

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Game theoretical "rational" opponents are defined according to certain strict criteria. It can be mathematically established that two opponents who fit those criteria will choose the $2 answer when facing one another. That's the heart of it.

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7) Philosophy is probably the most retarded field of study ever. T/F? No one can even agree on the meanings of important keywords. Also, I don't know why rationality is always assumed. "Emotion", feeling and instinct have done pretty damn well for humans and animals in general. It is basically ignored in philosophy, no? I'm rarely completely rational except when I'm sciencing and [censored].

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Philosophy is at the heart of almost all other fields of study, including math and science (not just sociology and anthropology). It's impossible to understand our scientific and mathematical heritage without understanding our philosophical heritage. Your assumptions are also invalid - emotion is definitely not ignored in philosophy, in fact one of the main challenges of philosophy is to explain how emotions work and what they are.

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8) How much of a joke are these majors in uni?
-communications
-sociology
-anthropology (wtf, it should just be lumped in with sociology already)
-women's studies
-whatever ethnic studies (asian, latino, black)

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I don't know if these majors are jokes, but there was a black studies class just before a seminar class I took this semester, which I was frequently early to, and it kind of scared me. I suppose he might have just been talking about black supremacy in a historical context and I overreacted, but the professor was dressed in tribal garb and has a big necklace in the shape of Africa and it seemed rather surreal.

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9) Guitar is rad.

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I wouldn't know.

[Borodog]

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Alright, just trying to tie up a few loose ends that I encounter in my studies.

1) In a cell, what causes vesicles, vacuoles, and other "stuff" to move in the cytoplasm? I'm looking for the cause of the force that gives them movement. Is it osmotic pressure? Electromagnetic forces?

2) Is race a social construct? Does it have valid scientific usage?

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Dawkins talks about this briefly. Even if it is a "social construct" does not mean that it does not have some objective existence in the real world. He cites the example of a picture of Colen Powell, George W. Bush, Rumsfeld, and Condoleeza Rice. When asked to identify the "race" of Colen Powell, people universally group him with Ms. Rice, even people who have no idea who any othe members of the photo are (yes, such people do exist). This is despite the fact that Powell's skin color is much closer to GW's and Rummy's than it is to Rice's. If there is such universal agreement amongst observers, there must be something objective that they are measuring.

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3) I get the impression that some of you (borodog?) here have some sort of theory of abiogenesis in your brain. Explain your ideas to me. I've read the wiki.

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I have no detailed theory. It is sufficient for me to understand that the building blocks of life, organic compounds like amino acids, would have been common in the conditions of the young Earth, and that there were an unimagineably large number of "chances" for a chance arrangement of these to form an auto-catalyzing (i.e. self replicating) molecule.

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4) May be tough to answer given that I haven't studied anything beyond mechanics and electromagnetism. What "causes" gravity to act on one object? Like a hand pushes a cart and makes it move, is there something that interacts with the object to cause the force? Is it just something which we don't have a complete answer to? Is the space warpage a satisfactory answer? Please don't respond with the equation, I know it.

5) Similarly, what causes electric and magnetic forces/fields? I haven't completely finished the course, so perhaps it explains later. But in the first chapter on electric forces/fields, it explains it by saying "it SOMEHOW modifies the properties of space around it". Big lol. How does one electric point charge "know" the other is there?

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In a very real sense this is not a meaningful question. We define mathematical abstractions like fields to describe observed phenomena. To then ask what "causes" them is outside the realm of science; it's metaphysics.

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6) Remember the giant ridiculous OOT thread about jason_t and John Nash, where callmeishmael called everyone idiots for choosing $100 +/- $1, instead of $3 (link someone?)? Well I was wondering WHY game theory gives an absolutely horrible answer to a basic problem.

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Game theoretical analyses can often give nonsensical results, because of their assumptions, because they have rules that are often inapplicable in real life situations, and because their solutions are worked through in ways that people do not under real scenarios. A real person does not play the game to "win" or to "not lose", he's plays it to make the most money he can. Arriving at a result of $3 when he knows he can have ~$100 is silly.

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7) Philosophy is probably the most retarded field of study ever. T/F? No one can even agree on the meanings of important keywords. Also, I don't know why rationality is always assumed. "Emotion", feeling and instinct have done pretty damn well for humans and animals in general. It is basically ignored in philosophy, no? I'm rarely completely rational except when I'm sciencing and [censored].

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I won't call it retarded, but a lot of what passes for deep or important writings is, to borrow a phrase, "philosophy fiction".

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8) How much of a joke are these majors in uni?
-communications
-sociology
-anthropology (wtf, it should just be lumped in with sociology already)
-women's studies
-whatever ethnic studies (asian, latino, black)

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Anthropology and sociology are not jokes. Unfortunately sociology has been largely taken over by kooks and crackpots. The rest are pretty much jokes. You should include Education in the joke category.

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9) Guitar is rad.

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I will not disagree.

[vhawk01]

As for the first question, your cells contain a large number of structural proteins that you dont see on any traditional light microscope, and a lot that you aren't even going to see on a regular TEM. This is the cytoskeleton. There are three main groups of cytoskeletal filaments, classified by size, and they do different things. The largest are the microtubules, and these make up the cilia on the surface of some cells, as well as the tail of spermatids. The second group is called intermediate filaments, a good example of which is keratin, which is used to hold cells together, as a protective coating for your skin cells, and other uses.

The third group is the one you are most interested in, I think, and that is the microfilaments. The microfilaments are exemplified by actin, which is in every cell (I think) and also has a special role in your muscular contractions. The way cells transport materials around can sort of be thought of as loading things in a minecart. The vesicles are transported along these long strands of actin filaments which crisscross the cell like a whole bunch of highways. They attach, shoot out to wherever they are going, and then jump off.

Keep in mind that these are metaphors and not EXACTLY what happens, but its very much like that.

[vhawk01]

Oh and yeah, unless you go to a school that has a specific reputation and focus for education, that major is a total joke.

[drzen]

[ QUOTE ]
Alright, just trying to tie up a few loose ends that I encounter in my studies.

1) In a cell, what causes vesicles, vacuoles, and other "stuff" to move in the cytoplasm? I'm looking for the cause of the force that gives them movement. Is it osmotic pressure? Electromagnetic forces?

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Isn't this the will of God?

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2) Is race a social construct? Does it have valid scientific usage?

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Yes and yes. The first doesn't preclude the second.

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3) I get the impression that some of you (borodog?) here have some sort of theory of abiogenesis in your brain. Explain your ideas to me. I've read the wiki.

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Some theory of abiogenesis in the brain? That sounds a bit odd.

I believe that the exact mechanism of abiogenesis will remain impossible to determine. However, there must have been a mechanism because life did evolve.

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4) May be tough to answer given that I haven't studied anything beyond mechanics and electromagnetism. What "causes" gravity to act on one object? Like a hand pushes a cart and makes it move, is there something that interacts with the object to cause the force? Is it just something which we don't have a complete answer to? Is the space warpage a satisfactory answer? Please don't respond with the equation, I know it.

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Erm, gravitons?

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5) Similarly, what causes electric and magnetic forces/fields? I haven't completely finished the course, so perhaps it explains later. But in the first chapter on electric forces/fields, it explains it by saying "it SOMEHOW modifies the properties of space around it". Big lol. How does one electric point charge "know" the other is there?

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They exchange particles, don't they?

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6) Remember the giant ridiculous OOT thread about jason_t and John Nash, where callmeishmael called everyone idiots for choosing $100 +/- $1, instead of $3 (link someone?)? Well I was wondering WHY game theory gives an absolutely horrible answer to a basic problem.

7) Philosophy is probably the most retarded field of study ever. T/F? No one can even agree on the meanings of important keywords. Also, I don't know why rationality is always assumed. "Emotion", feeling and instinct have done pretty damn well for humans and animals in general. It is basically ignored in philosophy, no?

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No.

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I'm rarely completely rational except when I'm sciencing and [censored].

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I suspect you are not clear on the meaning of "rational".

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8) How much of a joke are these majors in uni?
-communications
-sociology
-anthropology (wtf, it should just be lumped in with sociology already)
-women's studies
-whatever ethnic studies (asian, latino, black)

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Science majors just don't get laid. That may be because they spend their evenings playing D&D and computer games but it might also be because chicks think that being sensitive is cooler than being a nerd.

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9) Guitar is rad.

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That sentence doesn't make sense in so many ways it hurts to read it.

[madnak]

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Science majors just don't get laid. That may be because they spend their evenings playing D&D and computer games but it might also be because chicks think that being sensitive is cooler than being a nerd.

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Hey, we hang around on this forum so we don't have to be reminded of that.

By the way, I'm a bit puzzled by the varying responses here. But I suspect, based at least on vhawk's response to question 1, that the answers aren't as inconsistent as they appear.

[arahant]

This has pretty much all been answered (shocking), but i will point out that 4) and 5) are mostly the same question. When you push something, gravity is not involved. It is almost entirely the electromagnetic interaction between the particles in your body and the particles in the object being pushed.

As someone pointed out, it isn't meaningful to ask what 'causes' electromagnetic fields to exist. It can be helpful to think of the field in terms of wave/particle duality (i.e., it's not a 'field', it's a bunch of photons). It can also be helpful to think of it as a field. Either way, it is the same phenomenon.

I'm sure this was not at all satisfactory to you [img]/images/graemlins/smile.gif[/img]. What can I say, 'physics is hard'.

[vhawk01]

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Science majors just don't get laid. That may be because they spend their evenings playing D&D and computer games but it might also be because chicks think that being sensitive is cooler than being a nerd.

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Hey, we hang around on this forum so we don't have to be reminded of that.

By the way, I'm a bit puzzled by the varying responses here. But I suspect, based at least on vhawk's response to question 1, that the answers aren't as inconsistent as they appear.

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[img]/images/graemlins/confused.gif[/img] Am I reading this wrong, or do you disagree with my answer?

[theblackkeys]

I have just read the wiki on photons. My brain is in the process of exploding. Why would a textbook give that horrible explanation from my OP? At least it could have mentioned that the explanation will come later.

Thanks, all. I will post some more related questions in a couple of days.