Fred56

Traveling in time is not possible because time isn't like a line you can walk along or like a plane or like a 3d space you can move through. It has no dimensions, like space does. Traveling back to a previous time assumes that the "previous time" is "back" there, maybe it's recorded on some big universal recording mechanism, or something. Or maybe it's not there because there is no "there" for it to be. The relativistic time dilation issue is due to traveling at a reasonable fraction of c. So, as the previous post to yours indicates, someone traveling at high speed would age slower, at very high speed, even slower, and so on. Even the guys on the space shuttle (and airline passengers) do this.

OK. Have you looked at any slow-light or frozen light experiments? http://www.nasa.gov/home/hqnews/2003/may/HQ_news_03176.html

What I said initially is what many science writers are interpreting this to mean too. While it isn't true that "only men" can be geniuses, most news reports do say "overwhelming" or similar things about the difference in representation. Since men are also "overwhelmingly" present in the dotards section, we aren't supposed to get to big a head-swell. Perhaps you misinterpret me. The metaphorical "gamble in the genetic stakes" that occurs during gamete fusion, is where I was going.

I see. But here is the study:http://www.subjectpool.com/ed_papers/2007/Deary2007Intelligence451-456_Brother_sister_sex_differences.pdf And it does seem to be saying that males are more likely to be either highly intelligent or pretty stupid, compared to females. Why is this so controversial? Why is it surprising that females, in the genetic stakes, are given the safety of the middle ground, and males get to gamble on whether they get good or bad intelligence. Males then fill specialist roles, like hunting, exploring and other risky activities, while the females provide stability, or however it works out. The idea of males as a specialization is where this thread started. That said, one of the journalists did describe Professor Bates as a "brave man", for publishing his study. There are a lot of other threads about this study, many with disparaging comments, to say the least. Go figure.

Though some classify cliches as "sterile language". They can get irritating when someone overuses them. As I tried to illustrate. They convey an impression that the speaker, or writer, is unable to express themselves in an original way. But let's move forward on this...

I don't see that having females (the default genotype) fill a middle intellectual and presumably social position in a society where the males (the specialized genotype) fit in the "end-gaps" is a poor model or anything. This means the females would represent an overall mediating influence, between the dummies and the bright-sparks. This doesn't seem all that controversial. But it is only one study so it's maybe early days for definitive opinions. I haven't tracked down any online copies of the study itself so I don't know if males and females were analysed separately or what. So far I've only seen journalist reports.

Ok, I'll try again. What I'm getting at here is that we know about bonding and how solids liquids and gases are the three most common forms of all matter, but this is because we have explained it empirically, rather than from any first principles of bonding, say, or any other known behaviour of matter. We still don't really know why matter comes in these three forms, do we?

You nearly got this right. Actually the speed of light does not change. This is fundamental to Einstein's theories and explains why two observers approaching each other at 0.7c do not see the other approaching at 1.4c, not because light slows down, but because time slows down, geddit? Light slows down when it passes into a different medium, like glass. Someone has managed to slow down light so much that they claim to have "stopped" or "frozen" it altogether BTW.

When it comes down to it, at the end of the day, when all's said and done and the stitch has been stitched in time, cliches are just longer, more complex pause-words, bigger versions of “um” and “ah”. Wouldn't you say?

Right, but there is no Theory of Bonding which tells us what any particular combination of elements will behave like. When a new compound (say a pharmaceutical) is made, its properties (melting point, IR spectrum, solubility, etc) are determined after the fact.

Here's what an article http://www.dailymail.co.uk/pages/text/print.html?in_article_id=483707&in_page_id=1879 says:

Hm. You might be at a bit higher level than me on all this theory. I have only a first degree and studied Information Theory as part of a communications course. So this has already gone into territory that I'm not at home in, but I can deal with calculus etc.. What I'm confused about is how information can have entropy and reduce entropy too. Doesn't this require negative entropy, because I learned that entropy can only be zero or positive? But the point I suppose is that terminology can be deceptive in itself, mostly because of the different meanings of words like "information", "communication", and so on. I have done a bit more looking and Wikipedia says that Shannon wanted to call it information uncertainty (and this is still being suggested).

Distance is something we observe as being between things, or objects. Time, similarly is something we observe as being between events, or “messages containing information”. Two rocks on a field have a distance between them. Two events have an interval of time between them. If the rocks didn't have this distance between them, they would be the same rock. If distance (space) didn't exist, all objects would be the same (be at the same place). This object would have no volume (there would be no space to occupy). This non-object is something like that out of which the cosmos sprang, somehow. There was a sudden existence of space and time from literally out of nothing, which continued to expand and which suddenly was supposed to have expanded (inflated) at an almost asymptotic rate until about 3 sec. after the start, or the moment of creation - the first Planck moment of time. It has continued to expand after this first “big bang” until today, 14.5 or so billion years later, where this initial expansive force now seems to be being countered by an even more mysterious “dark” energy. Space itself is being created by this expansion, as the distances between the large collections of objects (galaxies) continues to increase, despite gravitational interactions that cause clustering and grouping of galaxies into vast sheets and filaments. Enormous voids are also created though, and overall, the cosmos continues to expand. This creative process was not like an explosion, which has objects receding from a common centre. All objects within the created space are receding at a constant rate from each other, relative to distance. This is an overall expansive process, the creation of space itself. As observers within this space, we not only see that we appear to be at the centre of expansion no matter how far out we look, but that the most distant objects have the greatest recession rates from us. This apparently unique view can be explained as above, so that all viewpoints would look like a centre of expansion. We observe that a lot of things are moving around, some in cyclic or repeating patterns. These movements are observable because we “know” that certain images our brains process arrive at different times. We process these images along with inbuilt timers and counters that give us an innate sense of “previous” event and “future” event. That give us our sense of Time. This sense, something all sentient animals with these inbuilt “interval sensors” must have, along with our other external senses, allows us to navigate the environment, to find food and so on. Our sense of time should perhaps be added to the other five that are acknowledged, the others wouldn't work too well without a sense of time.

just watching a doco about Passchaendale, the WW1 battle. My mother's father fought at the Somme, but was injured and shipped out so he didn't get to fight this one. So I'm here writing about chromosomes, which I got some of from him in my case. Just a weird incidental thing there. Anyway I think it might be inaccurate to say that mammals "start out as" females, because each zygote, barring any problems, should have either XX or XY so already be male or not. Despite the sex chromosomes not starting up until later in the gestation phase, the sex is already determined at conception (as long as a Y is present, in the case of a male, and it hasn't undergone any crossover).

Does anyone know the Shannon entropy of DNA (any representative organism will do)? Or does anyone know how to calculate this with any accuracy or even within the ballpark?

I think this thread might be getting just a tad bogged down with semantics here. Which of those 19th century dudes said "heat is motion"? I haven't seen "entropy" mentioned yet either, which term can mean a few "different" things, but they all use a very similar set of equations. A comment about the dimension of time: we can easily represent time as an axis on a graph or plot, but we know that this is a simplification, because time doesn't increase in any direction, it increases "everywhere", in all directions, as it were, but in a non-reversible or uni-directional way, like entropy. This is a bit of a conundrum. It also slows down for objects (like the ones that collide with the upper atmosphere and produce cosmic rays) that travel at a significant fraction of the speed of light. This means the journey, for them, seems shorter (which is why many of them manage to last the distance, apparently).

Interesting. My experience is that very few textbooks say this explicitly (maybe it's a "male thing" -most science writers are male), some sort of hint at it. That reference is the first time I've seen it written down in a specific way. Not sure how many people you would need to stop and ask before some one said "Oh yes, I know all about how humans, and mammals in general, all start out as female, and that the Y chromosome, which evolved from the X, is what produces a male". Where you did the survey would also make a big difference . Oxford campus or downtown London, say.

Your argument has so far also completely avoided the fact that CS also studies architecture of real-world machines and is partly an engineering discipline. The effect CS studies have had on chip makers is one example of this (not to mention all those communications equipment makers).

Q. Do we know why there are three kinds, or states of matter (at least in the ordinary world) or is this like the atomic particles, we know about them because of observation, rather than the predictions of some theory?

Apparently all that you need to do is build a large negative-energy (whatever that is) generator and move it to the desired destination (however many parsecs that might be) and bob's your uncle. Something like that anyway.

Another question about this might be: how valid is the concept of “normal” genome or “specialized” chromosome? In mammals, certainly there is the appearance that the Y was derived or evolved from the X, but other animals have what looks like a differently evolved sexual-selection process, based on quite different arrangements of chromosomes. In birds, the mechanism is not as well understood (are males the “default” genotype, or females? Do the sex genes switch on or off the sexualization, and of which sex? Does the male become a female, or vice-versa?). I don't think you will find the idea of the male sex being derived from females mentioned in many biology textbooks, either. By "my proposal" I assume you mean: the Y chromosome is a specialization, and so males are also "special" as in the title. Well, how does XXY syndrome detract from this, if that is what you think it does? XO sex-determination is found in some insect orders. Hope that isn't a Freudian slip there.

oops, yes perhaps I shouldn't have had birds in there, and yes, insects have a range of sex-determination processes, some animals use temperature (e.g. the tuatara lizard). I was being too general I see. The mammalian XY/XX sex chromosomes are well understood and the most familiar to people which is one of the reasons I didn't get into all the others. My mistake. I think the overall theme of my post still stands up though. I should have specified that this particular chromosomal sex-determination is found in mammals (which includes marsupials and monotremes, right?)

In species that use sexual reproduction, the female has a full normal complement of chromosomes, the male has an almost normal complement with a single non-matching pair. These are the sex chromosomes. In the female, these are a normal matching pair of X chromosomes, with the usual double copy of each gene. The male has an XY pair of sex chromosomes, with no double copies (genes from the Y only are expressed and lead to the development of male physiology). So the male seems to be a specialization of the female (apologies to the book of Genesis). This is further corroborated by observations that, in many species the male has a specialized role. In some, e.g. the lion, males do little more than provide sperm (the key purpose, perhaps, of sexual reproduction), while in others, e.g. some penguins, the male plays a close part in the nurturing process, during incubation especially. In humans, a study has found that, intellectually at least, females (the default genotype) fill the middle ground and males the start and end sections of the bell curve. This means that males are either stupid (low IQ) or intelligent (high IQ), and females are of average intelligence. Of course there are exceptions and this is only a single study, so far. But there it is guys, women can't be geniuses, only men have this potential. We hybrids can be cheered by that, the downside being we are also potential dolts.

OK I didn't really mean to get into ergodics so much, either. Rather look at the fundamentals of what information is and what entropy is. Shannon was apparently against calling it information (not sure why) but there is an argument that information reduces uncertainty, and so entropy. Where does that go? Information, which "has" entropy, can reduce entropy, or something. Negative entropy? I think there's something wrong with that argument.

But how do you avoid the perception of something when trying to define what it is? Our perception of time might well be a different thing from time itself, but where else can we start from? Surely the "scientific" definition of anything proceeds from our perception, our experience of it? Of course, most people believe in an external reality which would exist if they weren't around to see it, which implies that time is also an external thing and exists regardless of intelligent observers. I think that both are needed. Without the gaps or intervals, there wouldn't be any way to differentiate between events. Without events, there's just a bunch of "non-intervals" of time (because an interval, by definition, is something between events). Likewise, without objects there can be no distance between them, and vice-versa. I guess that depends on whether you believe having an "innate sense" is the same as "knowing". We certainly do have this innate sense, due to the internal clocks we are all born with (along with most other sentient animals). Non-sentient (and perhaps sessile) creatures don't have these clocks and so cannot have the same sense that we do (though we can't say they have no sense of time at all).