RoyLennigan

A few hundred is probably too short. If we calculate with a generation of' date=' say 30 years for humans, 300 years are only 10 generations.

Unless there are some catastrophes that result in significant, yet somehow specific elimination of a part of the human gene pool one would not expect significant changes.[/quote']

of course. but even in one generation there is the possibility of a mutation that could make the offspring have a very different and new trait that the parents did not have. whether or not that mutation is beneficial is completely circumstantial (and usually it is benign or harmful). but with an environment change (such as isolation in deep space or a new planet or a post-armageddon earth) any minor advantages would be selected for very quickly. you can't put a time frame on how long it takes for speciation to occur because it could be as short as 2 or 3 generations or it could be longer than 1000 generations, or it could never happen. all it takes is one change in one organism that is better at survival and reproduction than the rest.

 

the problem with seeing any major change in human evolution is that we have adapted our environment to fit us, instead of the other way around. by making our environment a perfect habitat for ourselves, we no longer need to change to better fit our niche. cochroaches and sharks have remained relatively unchanged for millions of years because they fit their environment so well. we will continue to stay nearly the same as long as there is nothing to threaten our general existence. but there is still some selection--those that cannot survive wont; those that cannot reproduce won't add to the genepool.

Thanks for all the replies! When do you think that will happen-the next stage?

its not an event that you can wait around to happen. its going to happen very gradually with short periods of intense environmental change that spurs selection for more rare traits. so it could be a few hundred years or it could be a few million years.

Anyone with half a brain can predict the effect a few drinks will have on them. Whereas with drugs it doesnt matter how experienced you are with them or how careful you try to be, as the effects it will have on you vary from person to person and even from one experience to the next. Also when i buy say a case of Miller i know what it is im getting. Whereas with any hard drugs no matter how reliable you think your dealer is you still run a risk of getting stuff that is laced with god knows what or is far more pure or impure then you think it is. Even if you do get good quality stuff your still in potential danger of having it interact with your body in unexpected ways and perhaps giving yourself a heart attack or seizure. The mountain is a more or less predictable challenge as you can prepare yourself for what your getting into, wheareas with drugs its pretty much a coin toss every time

it all depends on how smart you are. i've been on many mind-enhancing substances including lsd and mushrooms. never, i repeat never have i had the desire to do anything like walking into traffic or jump from a building. on these drugs i feel like i am part of the world around me and i so i know, even better than while sober, what would happen if i did something like that. the most dangerous thing i've done while on acid is balance across a boardwalk about 25 feet in the air and a couple hundred yards long. but i would never have even contemplated getting up there if it had been any higher than it was.

the people who end up dying or seriously hurting themselves on these kinds of drugs are the ones who arent smart enough to know how they could affect them. it is not the fault of the drug, it is the fault of the person taking the drug. psychadelics like lsd and mushrooms have absolutely no chance of doing any physical harm to your body just by taking them, no matter how much you take. you could OD on applesauce before you ate too much acid to kill yourself. the only problem is when you start taking it from strangers or when you don't know what you are taking and what it will do to you. i only messed around with stuff that i got from friends who had tried it before so i knew what to expect. its only a coin toss if you have no clue what you are doing, in which case you should not be doing drugs. i would be immensly glad if all the people who were ignorant of how drugs work just quit doing drugs so that there would be more for the ones who knew the purpose of drug use (and its not just to get f***ed up and feel different).

on hallucinogens i've had powerful revalations on how the world around me works, and i've felt myself as part of the universe, not just in it. as mimefan was saying, it is due to the irresponsibility of those taking the drug that causes them to do such irrational things like jumping off a building--it is not because of the effects of the drug alone.

Ugh' date=' for all intents and purposes, mutations are random.

 

However, those lifeforms who cannot outcompete their neighbors for resources, or are eaten as food, or are in some other way removed from the gene pool do not reproduce. Only the adept survivers (who have working sexual hardware and can attract a mate) reproduce, hence the "non-random" bit[/quote']

yes, 'for all intents and purposes' mutations would be random, but not randomly passed on, as you are saying. it is the natural selection that makes the process non-random and based on strictly cause and effect events; a mutation gives a certain fish a sleeker, more muscular body and the effect is that it can swim faster, therefore surviving in a situation where others of its species can't.

no processes in the universe are random, including evolution. the closest to randomness you get is probable events at the quantum level. every action is dependant upon these quantum events, and so everything is just a probability. but when looking at actions on a larger scale--say the reactions of chemicals and the formation of life--it can be seen as being deterministic. effect follows cause; life is formed by this loooooooooooong chain of cause and effect. thus, the origin and evolution of life is not random.

there are no steps forward or back in evolution. changes occur due to the environment an organism lives in. obviously, in the environment the snake was in, hips and hind legs were of less use than no legs at all. maybe the sleek body made it easier to evade predators, or dig underground, or swallow their prey whole, etc. whatever the cause, it the change allowed the snake to survive better than others without the change, and so its genes were passed on to more offspring.

Where is the rock solid proof that the world has experienced millions of years? Just as you believe in millions of years based on faith in what you have heard and read I also the same faith in my belief in thousands of years. There is no scientific way of proving millions of years.

if you take theory as being faith, then why are you attacking it thus, unless you expect your faith to be attacked in return?

with all due respect, i'd rather read from the nature around me than from the words of a book. nature cannot lie.

and to the thread starter, thank you for the timeline, its a really great visual aid for understanding the order of what most likely progressed.

1.If I'm on a train that is moving along at the speed of light or a couple hundred miles an hour under' date=' if I shot a gun what would happen?

 

Would the bullet not fire? Would it in fact do what bullets do which is come out of the gun at over 1,000MPH + whatever speed your traveling?[/quote']

 

under the laws that modern physics has learned, it would be impossible to do any of this so the question is moot.

 

2. What's the force behind light? why does it move, what makes it move, why can we slow it down but not speed it up? Is it a wave or a particle? (I dont fully understand how waves work).

 

i'm not sure if we understand the force behind light. photons are created when one or more energized electrons move down in orbital levels around the atom. the distance the electron falls matches the frequency of the photon emitted.

 

the reason we can 'slow light down' is because we can make it travel through mediums other than a vacuum. light is constant in a vacuum, the speed is c. but when travelling through water, or glass, or other objects, the speed is slower. it is by changing the medium that we slow photons down.

 

3. Why is the speed of light the determining factor on the limit in speed? For instance, if light was only as fast as 1MPH, we wouldn't be able to move faster then 1MPH right? Why is that is my question.

 

photons have a mass of zero (as do hypothetical gravitons). there is nothing lighter than it. there might possibly be negative mass particles, but they havent been found. because it has a mass of zero, and zero is the least mass in the universe (that we know of) then it makes sense that nothing can go faster than it. einstein shows us that as you approach c, the speed of light in a vacuum, your mass gets infinitely larger and you will therefore need an infinite amount of thrust to propel you faster. this is obviously impossible (at our current comprehension).

 

Is there any reason to think the way things move is in a fixed ratio of the speed of light? For instance, light goes 669,000,000MPH, so lets compare it to an object that moves 66,900,000MPH. In a universe where light only moves 10MPH, would that object move 1MPH?

 

i don't see the relevance of the question. i would think that, logically, all movement is at a fixed ratio to the speed of light. the greater the mass, the more force is needed to propel it.

 

4. If it takes all the energy in the universe to have enough force to move something at the speed of light, why does light move as fast as it does? My guess is that it's weightless but then that confuses me towards light slowing down in different mediums. Atleast, I take it, you cant outrun light in any medium?

 

you are right that photons do not have any mass. it takes in infinite amount of energy (not the same as all the energy in the universe) to push something at the speed of light. as the speed of an object increases, so does its relatavistic mass. the greater the mass, the more energy is needed to push it. photons are massless, so they always travel at the speed of light, they can't travel any slower or any faster. but light travels at different speeds through different mediums, and the fastest through a vacuum. i would imagine this means nothing can travel faster than light through the same medium, but i am not sure about this.

the theory that our universe is comprised of 11 dimensions is purely conjecture. there is no evidence supporting this. i believe it was developed as part of string theory.

i think that a singularity (what supposedly exists at the center of a black hole) would be 1 dimension, but i am not completely sure.

neutrinos have a mass, though very small.

perfect humanity would be complete understanding among everyone. there would be no ability to lie. there would be only shared memories and experiences instead of language. math would be our written record.

i've read from several articles that dark energy creates a negative pressure and would therefore push all matter away from it. if what this guy claims is true, then how would it be possible that black holes appear to suck matter towards them?

Correct me if am wrong, but expansion uniformly in all directions implies it once started from something closer together. Is there any reason why 13billions year old objects are not found nearby?

everything has been shaped and reshaped, i'd be surprised if there was any kind of 'object' anywhere in the universe that was 13 billion years old. but the matter that makes up everything in the universe--me, you, the computer, etc--is as old as the universe.

You ask "how do you get an atom from it [a wave]"[/i']... well the atom is both an atom and a wave at the same time, when you observe something you do it in a way that it returns a specific result. What I mean is that you set up your observation equipment to observe either a particle, or a different setup to observe a wave. So depending on how you setup your observation equipment the atom will either be a wave or a particle.

an atom is matter, a photon is a quantum of the electromagnetic field. atoms do not make up EM waves. i think you are confusing atoms with particles. what he was asking is how could you theoretically get matter from energy; how could you turn an EM wave into matter.

For Roy the thing is "if" something like it is observed. No-one has been able to demonstrate the prescence of Dark Matter or Dark Energy to any degree of certainty. While I agree if something can be demonstrated with certainty then by all means use that as the explanation. But until that point why would anyone wish to dismiss a possible explanation, without consideration? I am more curious to determine if a minute gravitational attraction from basically an infinitely distance sphere could somehow be measured.

the only evidence for dark matter is the fact that it is the only thing that can be explained mathematically to fit the known model of the universe. it was proposed because it could explain why the universe is (or was) expanding increasingly.

this diagram explains the theory better:

http://map.gsfc.nasa.gov/m_uni/101bb2_1.html

i am also curious about gravitational attraction over large areas. i think most physicists say that gravity travels at the same speed of light, while a few mention that gravity isn't limited to a certain speed, seemingly in contradiction to GR. that 'boiling pot' theory would only work if gravity somehow traveled faster than light. much, much faster, which doesn't seem to hold up in GR at all.

Lets say that one day on mercury is 2 earth years (i think this is right' date=' but if its not, it doesnt really matter) If you traveled to mercury, would one day FEEL like 2 years, or would it feel like one day?

 

this may be a stupid question, but please no flaming.[/quote']

one mercurian day (the time it takes for the planet to make one full spin) would feel like 2 years because, on earth, the same amount of time would be two years. the way we percieve the world does not depend on which planet we are on. in space we percieve time exactly like we would on earth.

 

btw, one day on mercury is 58.64 earth days.

I guess I would call myself a speculative physics geek. So when confronted with the concept with a universe expanding at an increasing rate' date=' I began to speculate. Everyone in the science community seems to think it is some sort of exotic 'dark matter' which no one can find. I think I have a simpler solution.

 

I read back in Scientific American a few years back about theories of infinite universes. One theory describes space-time as infinite in all directions. The speculation is that local universes burst into existence like bubbles in the bottom of the pot of boiling water. Randomly throughout spacetime. This means that in any direction at a sufficient distance is another local universe expanding similar to our own. These universes exist so far away that most would die a cold death before their expansion ever brought them into contact with each other.

 

Now assume that their are huge massive UNIVERSES, not just galaxies or stars, extremely far away in every direction. The gravitational pull of these universes, because of their astronomical masses would not be negligible despite their distance. Since they exist in all directions, the net effect should be to pull our universe apart at an increasing rate in every direction. No mysterious dark matter required.

 

Comments?[/quote']

that's a good hypothesis, but it wouldn't be nearly as simple as the dark energy hypothesis. effects of what could only be explained by dark energy are observed all over the universe. it pushes positive energy and matter away from it, and pulls negative energy towards it. if it, or something like it, is observed in the universe already, and its presence explains expansion of matter/energy, then it would be a simpler and more accurate description than a hypothesis with no evidential support, even if it is from Scientific American.

 

with that said, evidence might be found supporting the 'boiling pot' hypothesis but also explaining the presence of dark energy, who knows.

The data coming from the edge of the universe, which appears to be accelerating is actually data from 13 billions years ago. It is not what is happening today. Today's data from the edge of the universe will take 13-14 billions years to reach us. What we do know for sure is that the further back into time one goes (oldest transmitted data), the more the universe was accelerating. This makes sense since the original expansion from 13 billion years ago accelerated rapidly. Data that is closer to real time, i.e., from a billion years ago, shows very little red shift, indicting the modern universe has decellerated. The imaginary fifth force should be directed to help explain the potential beyond the original expansion. The fifth force is entropy. Entropy acts, tastes, and smells like a repulsive force but is not a force in the technical sense.

of course data closer to us isn't going to be redshifted as much, its closer to us. the expansion of the universe is proportional depending on where you are in the universe. at the edges its going to be expanding more rapidly than anywhere else. closer to the 'core' of the universe the redshift is going to be much less and appear to show that the universe is expanding slower. now, if you're talking about the % of rate decrease then that would be a different story.

Resident Evil is a great movie, Dawn of the Dead too (the re-make), they had science in them din't they? well, maybe a bit,but great to watch none the less. I lovedthe Back to the Future movies, apart from the western one, too much of it was ruied by that Clara woman, falling in love with the Doc'

ah man the original dawn of the dead is a spectacular movie. the beginning is one of the best openings in a sci-fi/horror film i've seen.

solar flares would be a problem for longer trips through space. too much radiation.

2001 a space oddysey (arguably one of the best made)

contact (extremely realistic, it was written by carl sagan, c'mon)

donnie darko (even though its more cult than sci-fi)

blade runner

these are all awesome movies that really get you thinking.

Hi there, Im having a bit of a debate with my friends. Ice - is it the hardest thing know to man? I reckon it is.

what? no, why would you think this? diamond is the hardest known naturally occuring mineral. but there are several artificial materials that are harder. at colder temperatures, these materials are relatively harder than normally.

Matt' date='

It occurs to me there is a problem with this statement. Becaue I am pretty sure I saw a NOVA program that said stars going away from us are "red shifted". They would not be red shifted or blue shifted if light was always constant to the observer.

 

Can you or anyone else explain this?[/quote']

they are redshifted because the universe is expanding faster than the speed of light. or, if not faster, then space and time are being warped such that it seems that it is expanding faster than the speed of light. the distance between all objects in the universe is increasing incrimentally and proportionately to how the 'edges' of the universe are expanding.

 

redshifting occurs due to the doppler effect or because the space between waves in a lightwave is expanding and causing that wavelength to lengthen, which makes the light more red. with the doppler effect, if the object is moving away from us at high velocity, it is redshifted; if it moving towards us at high velocity it is blueshifted. in a redshift the wavelengths are lengthened, in a blue shift they are shortened. large gravitational feilds can shift the spectrum of light too. but the light is always moving at a constant speed, no matter what its wavelength is.

As far as I know, there is no direct evidence of Black holes. Seeing as how no light, or any other information can escape the event horizon of a black hole, Its practically impossible to observe one directly. The closest we have come is determining several Black hole "candidates", or systems where a black hole is thought to exist based on the behavior of visible objects in the area.

a black hole per se might not actually exist, but it is true that something like it does exist, which can pull light waves towards it in such a way that they apparently cannot escape. this is revealed by observations of how light is distorted around a canditate black hole in that there is intense light around it that is displaced from where it normally should be in space. at first it looks like a bright star or a quasar. its this intense gravitational lensing that provides evidence for a force that is explained by a black hole.

well, electromagnetism is one of the fundamental forces. magnetism and electricity are directly related. it is inherent in the atomic structure of everything.

http://en.wikipedia.org/wiki/Electromagnetism

http://hyperphysics.phy-astr.gsu.edu/hbase/forces/funfor.html