# greentea

Senior Members

47

1. ## Is There a Chance for Another Evolutionary BreakThrough

The next evolutionary breakthrough would be mental. Currently ideas evolve a lot quicker than genetic information. There is currently too much crap in the movies about mutant humans. http://en.wikipedia.org/wiki/Memetics
2. ## Hollywood's Science Blunders

"The day after tomorrow". Clearly the effects are ridiculous. Wally Broeker's theories as a background is also poor science. He is the prototype for the guy in the movie. Even some of the diagrams in the movie are from actual Broeker's presentations. I do not totally disagree with anthropogenic global warming, but it should be supported with real science not apocalyptic nonsense.
3. ## Who was the greatest scientist or inventor that ever lived ?

Da Vinci and Gauss. Edit: also Darwin and Pasteur from the biological sciences. People like Einstein or Watson/Crick might have made great discoveries, but these were things on their way. The truly greatest were ahead of their time.
4. ## what first sparked your interest in science?

Started with learning to read and count earlier than usual. Then got seriously ahead in math during primary school, turned to physics in high school (and some astronomy fascination for a while, of course), now in college moving towards biochemistry. It all goes naturally, I never had a particular desire to become a scientist, but it seems logical I end up there. Of course, there are a couple of people, mainly teachers that had a great influence. The physics teacher I had (outside of school) is practically the best in my country (measured by the number of his students' achievements).
5. ## Where are all the Deep Impact doomsayers?

well, having in mind that unfortunately the people who believe in astrology are so numerous, NASA will soon go bankrupt

exactly
7. ## A Deliciously Edible Common-Weed

sounds interesting, but do you really consider dandelions weed?
8. ## Problem

as I said, you can get away without calculus, it is just playing with fractions and some logic. start with the obvious - express the desired sum in terms of A,B,C only. it is a ratio of two linear combinations of A,B,C (expressions like xA+yB+zC, where x,y,z are some numbers). get rid of one of the variables in the numerator. it remains in the denominator, however. now you can realize what it takes to get a maximum value. i won't get further, try it out. just don't worry about calculus, this problem is simply advanced 5th grade stuff. (or whenever you study fractions)
9. ## Problem

any A,B,C that give A+B+C=0 will result in G+H going to infinity and I guess that is not what you are looking for, so please give us some more information. are there no other restrictions on A,B,C? for example, if they have to be positive numbers, there is an easy solution without any calculus involved.
10. ## Book Suggestions

I am currently (which includes a long period) struggling with Roger Penrose's 'The Road to Reality'. It is not exactly beginner, but is definitely worth having in mind (maybe for the future). Starts from basics and gets into the most elaborate current theories, building all the physics and math on the way. The author claims that you can skip the equations and still have pleasure in it, but I doubt it. The math is quite deep and fundamental.
11. ## Behold the Hominid

Not tool making and not communication. Both are evident to some extent in animals.
12. ## Perpetuum mobile?

Obviously your web translator does not work well, since you do not realize what are you talking about.
13. ## Permutation question (final exam tomorrow)

note: i use . for multiplication what is the number of possible combinations (or whatever this is called, i never remembered them) of five balls out of 10? 10.9.8.7.6/(5.4.3.2.1) = 252 why? for the first one you have 10 choices, for the second 9, etc (since they are not replaced) you should also take into account that you do not care about the order. only which balls are taken. since there are 5.4.3.2.1 ways to order five balls divide by that number example: you took balls 9 4 2 1 7 or 7 4 1 2 9 - same for you. so 120 ways to rearrange those. that is true for each set of five balls you took out of the ten. therefore divide to get the 'different' combinations (in the sense we are interested). next, let's look at color to get at least 3 balls you need either 3 or 4 (all) in a similar manner you can determine the combinations 4.3.2/(3.2.1) for the 3 red balls. then you must also have 2 black balls that make 6.5/(2.1) combinations. Total = 4.15=60 in the case of 4 red balls 4.3.2.1/(4.3.2.1) - only one combination in which you have them all, kind of obvious. for the remaining black 6/1=6. Total = 1.6=6 Total combinations for 3 or 4 red balls 60+6=66 66/252=0,2619 I am explaining in a quite poor way since i do not remember what the proper terms were.
14. ## Quotes!!! Lets make a BIG collection!

"If knowledge can create problems, it is not through ignorance that we can solve them" - Isaac Asimov "It is better to keep your mouth closed and let people think you are a fool than to open it and remove all doubt" - Mark Twain "The trouble with having an open mind, of course, is that people will insist on coming along and trying to put things in it" - Terry Pratchett "Do not go where the path may lead you; go instead where there is no path and leave a trail" - Ralph Waldo Emerson
15. ## General Questions

1) does not seem likely to me. the only 'evidence' i can think of are the myths of surprisingly similar creatures like dragons. 2) maybe it would, but if you refer to the 'flood' in genesis or any other recorded one, they are local events that affected only a certain territory. 3) no, nuclear winter is a hypothesis that can be hardly called scientific. it might be the case, but is based on speculations of the sort people use to predict how many intelligent species exist in the universe (like ... say 1 in so and so planets has this conditions, say there are so and so planets in a stellar system, stars in a galaxy, etc. there is almost no evidence behind these numbers, they are apriori probabilities) 4) i guess not, radioactive carbon has a relatively short halflife. assuming millions of years the quantity left would be undistinguishable from noise. however, i think carbon dating can state with significant certainty that dinosaurs are much older than for example 6000 years. 5) i do not know, never heard of 6) since 'bible' simply means book, there are many books about evolution. i do not think, however, that there is a single one that holds the truth like the 'bible' is assumed to. 7) i think the best arguments against creationism are in the bible itself. if you honestly try to read it literally you would face enormous incosistencies and contradictions, despite the efforts of numerous revisions to correct the problematic expressions. if you read it simply as a book, no problem. attack a creationist on 'genesis' and he will have to come with really 'creative' ideas to explain the two (or more) distinctly different stories told. not that you can disprove god in this way, but at least a literal interpretation of the bible has no support. on the other hand, any faults creationists find in evolution does not disprove it (unless it is something really huge), since science does not claim to be 'absolutely' right.
16. ## Why is Freud so famous?

the revolutionary contribution of Freud is not just relating everything to sex, but simply creating a model for the human psyche that is related to the body. its further application to various situations can be quite doubtful and a sort of chamanism. but it is like every model that goes beyond its realm. the main flaw in his theory is the assumption that acquired traits can be inherited, which contradicts most of modern science (although obviously there are mechanisms for epigenetic inheritance, as well)
17. ## identities

start with the definition of sec and tan in terms of sin, cos then all that you need are the identities for double angles of sin and cos
18. ## intx^x

maybe it was the bible. you know pi is equal to 3 there.
19. ## The first dimension

the transition from a dot to a line is indeed a big problem and a lot of math revolves around it. but it seems to be on the boundary with philosophy. and a big problem for imagination which is tuned to 3d. i personally think that actually people naturally think of the dimensions backwards. a plane is imaginable contained in 3d space, then a line lies on a plane and a dot is a location on that line. then, after this intuitive approach, you formally construct mathematics beginning with the dot.
20. ## huge accelerator

you seem to be forgetting that velocity is a vector, so changing direction is acceleration, as well. your idea works only on a straight line and getting to any speed of the order of c at 1-2g will take a looooooong way.
21. ## Telepathic Resolution Theory

that is what I meant by 'selective memory'. hope that is the right term. but totally rejecting any possibility for another explanation on this basis sounds a bit unscientific. I mean, how can you disprove that some event is random.

It is more like 30 - 30/(27^1/3) since height is one-dimensional, while volume is 3D. If it is simpler think of a cube. 8 times bigger volume means only twice the side. Same with any figure that is scaled.
23. ## Overpopulation

don't worry, there are plenty of politicians taking care of that by waging wars and refusing to fight poverty. we must first get rid of them, so that the problem of overpopulation arises.
24. ## Telepathic Resolution Theory

it might be not serious, but definitely sounds better than a shampoo advert. while i am quite sceptic, some phenomena like people turning around when you stare at their back seem quite common. the only 'scientific' explanation i can think of is coincidence and selective memory which accounts for a lot of superstitions. i have never heard of measuring 'brainwaves' (whatever is meant by this) though. however, i find speculating about this subject much more interesting than something like aliens, for example.
25. ## Influence of wind on sound.

so, it's just doppler shift. I thought of that, but seemed too simple to be true. how about wind blowing perpendicular?
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