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Plant Sciences, Zoology & Evolution / Re: Is there any such thing as animal "culture" ?

« on: 23/02/2009 21:56:48 »

There are certainly cultures in a variety of mammals. Some groups of chimps (or was it bonobos?) hunt ants by poking sticks in anthills, there seem to be two groups of killer whales one lot which hunt fish and the other lot hunt seals. This seems to be a cultural difference at the moment (although it may end up splitting the species in the long run. There has been some work done on birds having different dialects in their song depending on where in the country they are etc.

So yes I think that sophisticated mammals do have culture if you define it as an inherited behaviour which isn't genetic and varies around a species.

Yes. I'm thinking of culture as any learned behavior. Domestic dogs reflect human culture to a large extent. They would not fit in very well with truly wild dogs such as dingos, although they might be able to adapt to the street life of feral dogs. My basic question is: To what extent do evolutionary biologists take culture into account? Culture is not communicated through genes. Richard Dawkins uses the concept of "memes" to explain this kind of communication. What interests me is that I don't think cultural adaptations can be explained by random genetic mutations although a selection process clearly still operates. Cultural selection would probably involve a certain amount of intentional action such as to find new habitats or to modify diets.

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Plant Sciences, Zoology & Evolution / Is there any such thing as animal "culture" ?

« on: 22/02/2009 23:10:48 »

It's common knowledge that animals removed from the wild at a young age will not survive if returned to the wild at a later age even if they remain healthy. This is particularly true of mammals. Mammals must be allowed to absorb the 'culture' of their species. I've never heard the word 'culture' used this way, but it seems appropriate. It seems the higher up the evolutionary scale, the greater the role of culture in survival. If this is the case, than genetics appears to play a diminishing role in survival and therefore the direction of evolution. Any views on this?       

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Physics, Astronomy & Cosmology / net energy of the universe is zero?

« on: 10/02/2009 10:13:37 »

Here's a short popular science article on zero net energy which I believe contains a fallacy. Does anyone see it?

www.astrosociety.org/pubs/mercury/31_02/nothing.html

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Physics, Astronomy & Cosmology / net energy of the universe is zero?

« on: 08/02/2009 22:53:19 »

Okay; I understand your point. It just surprised me that someone would assign the metaphysical term to a theory that is so widespread in the mainstream physics community. I myself suspect that the Big Bang theory is more of a creationist scheme than a scientific theory.

As I said,I consider the Big Bang model (including inflation) to be  scientific down to the Planck limits. It explains a number of observations and is subject to ongoing testing. It's a working theory. You seem more skeptical than I am. I don't think it's creationist. It's based on the evidence. Creationism imposes a concept that cannot be tested or falsified and it adds nothing to a scientific debate.

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Physics, Astronomy & Cosmology / net energy of the universe is zero?

« on: 08/02/2009 21:30:18 »

Stevewillie, the Higgs particle is still an idea, not a truth.

As from where you get that electrons are 'smeared out' in spacetime I don't know?
Do you mean photons?

I said 'possibly' the Higgs field. Regarding the unobserved electron being "smeared out", I'm sure you know that 1)the electron exists as both a wave and particle(as for any other quon, 2)has no specific location until its observed and 3)there are no prescribed limits to the extent of fields in QM. Moreover large quantum fluctuations can, in theory, occur anywhere in spacetime. Spacetime is not nothing.

author=Vern link=topic=20047.msg225699#msg225699 date=1234054241]

Regarding the vacuum, it's not nothing. It's spacetime and is 'filled' with  electromagnetic and gravitational fields and possibly the Higgs field. Moreover QM tells that particles like the electron are smeared throughout the vacuum (until someone looks at them)and the vacuum holds vast amounts of potential energy.

I'm still trying to figure out what it was about the post you tagged as metaphysics, that was metaphysics. Was it the notion that Lamitre proposed, the Primevial Atom. That paper by Lamitre was the origination of the Big Bang theory? It still is the mainstream scientific account of creation. If not that then what?

Any proposition that cannot, in principle, be verified or falsified by some observation or experiment is metaphysical. There's nothing necessarily wrong with metaphysical statements as I've already said. But they are not scientific. To say the universe emerged "from nothingness" is metaphysical. It may be correct, but it can't be verified or falsified in principle. If the Planck limits could be penetrated by observation or experiment, that would change the situation. I'm not questioning the status of Big Bang cosmology down to the Planck limits.

I'm still waiting from someone to directly address the idea that the net total energy of the universe is zero and why gravity represents "negative" energy. 

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Physics, Astronomy & Cosmology / Re: What happens to the time if I can travel faster than speed of light?

« on: 07/02/2009 23:07:39 »

A lot of discussion for a 'troll' question. That's what some posters want. Don't encourage them.

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Physics, Astronomy & Cosmology / net energy of the universe is zero?

« on: 07/02/2009 22:51:15 »

But I like metaphysics:)
It discusses the definitions for our equations.
That's where it all start.
Make a wrong turn there, and you will be a long way from ever getting your ideas to fit.

Nothing wrong with metaphysics. You just need to remember it's not science. It's philosophy. Some philosophies are better than other philosophies. The philosophy of science is how we think about science. Therefore it's important. In fact, it's the Wittgenstein-Popper philosophy that guides modern science and it tells us not to confuse metaphysics with science.

Regarding the vacuum, it's not nothing. It's spacetime and is 'filled' with  electromagnetic and gravitational fields and possibly the Higgs field. Moreover QM tells that particles like the electron are smeared throughout the vacuum (until someone looks at them)and the vacuum holds vast amounts of potential energy. 

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Physics, Astronomy & Cosmology / Sir.Isaac Newton Vs. Albert Einstein ? Who is the Best ?

« on: 06/02/2009 00:32:24 »

Guy?

It's Marie Curie.

Got me good there. Sorry! I thought it might be Gregor Mendel in cleric garb, but couldn't figure out what he was doing with the flasks. The face and hair style fooled me as well as the fact she appears taller than all the rest. All gender stereotypes. I stand corrected again.       

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Physics, Astronomy & Cosmology / Sir.Isaac Newton Vs. Albert Einstein ? Who is the Best ?

« on: 05/02/2009 22:56:46 »

The guy on the right is Nicholas Tesla.

Nikola

I stand corrected. Who's the guy on the left?

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Physics, Astronomy & Cosmology / net energy of the universe is zero?

« on: 05/02/2009 20:58:28 »

Traditional cosmology models (I believe) consider that all the matter-energy that exists today existed at the earliest epoch in an incredibly dense state. Where it all came from remains beyond any science (ie the Planck limits). But what's the basis for saying that it all came from nothing at all?

When folks saw that everything in the universe is speeding away, they extrapolated it back to a beginning and concluded that everything came from the same place. It seems that we have a great willingness to dispose of natures laws if it fits a pet scheme. In this case it began with Georges Lamitre's Primeval Atom. Lamitre envisioned the creation of the universe out of empty nothingness.

That's metaphysics. "Whereof we cannot speak, we must pass over in silence" (Wittgenstein). Hawking does not do metaphysics. He must have good reasons for considering that the net total energy of the universe is zero. He talks about it in his books (either "About Time" or "A Brief History of Time" but I can't locate it right now.) He considers gravity to be "negative energy" as opposed to the "positive" energy of non-gravitational forces over a distance. I simply don't understand how this works or why this concept is needed. My understanding of current cosmology is that there was a single unified force at just after Planck time (about 10^-43 sec ATB) and gravity split off soon after. Clearly this unified force was "something". Neutrons resulted when positive protons joined with negative electrons, and their charges canceled, but total energy was conserved. Total energy is the basic currency of "stuff" in the universe. How can it be zero?

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Physics, Astronomy & Cosmology / net energy of the universe is zero?

« on: 05/02/2009 09:29:05 »

I like the idea that the net sum of the universe is zero, QM tells us that particle/antiparticle pairs can appear from nowhere as long as they don't hang around to long so why not the same with the universe on a larger scale.

Particles can condense out of energy fields but total energy is should be conserved. I think the Uncertainty Principle allows for the existence of spontaneous particle-antiparticle pairs, but they immediately annihilate. Again total energy should be conserved except for the the briefest moment. Are you suggesting that the entire universe exists on the barrowed energy allowed by the Uncertainty Principle?

Traditional cosmology models (I believe) consider that all the matter-energy that exists today existed at the earliest epoch in an incredibly dense state. Where it all came from remains beyond any science (ie the Planck limits). But what's the basis for saying that it all came from nothing at all?   

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Physics, Astronomy & Cosmology / Sir.Isaac Newton Vs. Albert Einstein ? Who is the Best ?

« on: 04/02/2009 23:04:04 »

Who is the old man holding a skull in his hands? And the guy on his right is?

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Old one holding skull is Charles Darwin .........!!!

The guy on the right is Nicholas Tesla.

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Physics, Astronomy & Cosmology / net energy of the universe is zero?

« on: 04/02/2009 22:55:41 »

Stephen Hawking and others have proposed that the net energy of the universe is zero by considering gravitational energy as negative, and all other energy forms as presumably positive (or possibly neutral?). On the surface, this sounds wacky to me. Even QM doesn't truly get something from nothing. Particles can condense out of energy fields and particles can be transformed into their energy equivalent through particle-antiparticle annihilation, but energy is always conserved. I understand that in cosmology, the stress-energy tensor of GR is what's conserved, not necessarily matter-energy. Does that mean that the total energy of the universe is conserved or do we really get something from nothing?

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Physics, Astronomy & Cosmology / Bose-Einstein condensates and lightspeed

« on: 03/01/2009 23:16:40 »

I found a very nice description here, even if somewhat old.
http://www.physicstoday.org/pt/vol-49/iss-8/vol49no8p11-13.pdf
And here you have a more concise one.
http://guava.physics.uiuc.edu/~nigel/courses/563/Essays_2008/PDF/bian.pdf

But you are correct Steve, the BEC will behave as if all atoms were in the same quantum state.
It's very strange ( and cool

Thanks for the references yor on. When you say BCEs are cool, you're not kidding, like a few pico-degrees Kelvin above absolute zero!

Stevewillie

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Physics, Astronomy & Cosmology / Bose-Einstein condensates and lightspeed

« on: 02/01/2009 20:42:31 »

When light is "slowed down" it is essentially the same process that causes materials to have refractive indicies which imply a slower speed for light.  The photons are always travelling at light speed but are continually being absorbed and re-emitted unchanged with a Hisenberg related delay between absosbtion and re-emmission. so in effect they are "new" photons.

I agree with you in the case of ordinary matter, but what about Bose-Einstein condensates (BEC)? Here you have the merging of distinct quantum  probability waves into a condensate that can be described by a single elementary wave function. This is no ordinary state of matter. In recent experiments, you can actually see a light beam slowly moving through a patch of BEC. My question is, does your explanation apply here where the condensate may in some sense be considered a single "particle"?

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Physics, Astronomy & Cosmology / Bose-Einstein condensates and lightspeed

« on: 01/01/2009 21:42:28 »

Light has been shown to be slowed dramatically in Bose-Einstein condensates (BEC-a quantum state existing very close to absolute zero.) What does this say about lightspeed as a constant? How does this affect the interpretation of the Lorentz factor? Does time "stop" for a light beam moving at only a few cm/sec?

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New Theories / global warming can cause an ice age due to increased polar snowfall

« on: 15/11/2008 23:14:56 »

Where would the political incorrectness come in? I could just be naive.

There is a political aspect to the entire global warming issue. While there is clear evidence of global warming and most climate scientists believe the human contribution to greenhouse gases is critical, some scientists challenge the latter. Such scientists are sometimes accused of being beholden to polluting industries and promoting 'junk' science.

The idea that global warming itself might lead to unexpected cooling is also controversial because it too is seen as favoring the interests of polluting industries and their polluting products. However, there is growing evidence of global "dimming" where particulate matter decreases solar energy reaching the earth's surface. This plus increased high latitude snowfall are reasonable explanations for alternative global cooling theories. In either case we are dealing with a dangerously altered ecology and polluting the atmosphere can't be defended.

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New Theories / global warming can cause an ice age due to increased polar snowfall

« on: 13/11/2008 21:47:29 »

You could be right but, in a system like the weather and climate, you can get chaotic behaviour. Huge swings can be caused by a factor you just didn't notice when you were making your prediction.

Of course, and this is not really a "new theory". However, this aspect of global warming is rarely discussed since it might be politically incorrect. This is not to deny global warming, but to point out a little discussed possible consequence of global warming. Monitoring expansions of perennial snowpack and glaciers is easy to do, and there is evidence that some high altitude glaciers, such as in parts of Scandinavia, have been growing year over year for the past few years.

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New Theories / global warming can cause an ice age due to increased polar snowfall

« on: 11/11/2008 21:10:45 »

I have found that it is unwise to speculate about the impact of global warming based on just a qualitative hypothesis. The battles about what would happen in a whole variety of complex scenarios is best left to the very complex computer models and even these are insufficient to include all the relevent variables, hence the doubts and inability to make definite predictions.

I agree. It's very complex and we don't know all the variables. However, it's fairly straightforward to expect rising (but still sub-freezing) temperatures will result in increasing snowfall in what is now a polar desert. The major lobes of the last continental glaciations in Europe were centered, not in Russia, but in Scandinavia and Great Britain where plenty of moisture was available and temperatures were not severe until the ice accumulated enough to effect temperatures. Year over year accumulations of snow pack in Scandinavia and parts of northern Canada would be a signal for a possible new glacial advance. 

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Physics, Astronomy & Cosmology / Re: What is a singularity?

« on: 09/11/2008 21:51:38 »

Without time you can only have a steady/stable state because you need time for the state to change.

Here's another example of someone treating time as a necessarily different class of dimension.
I don't think there need be such an essential difference.  A graph of x against y can be the same shape as a graph of x against t.
Differentiable and continuous functions can occur between any two variables. (At least in pure Maths)
Even the requirement, in our experience, that t can only increase, could be merely a local constraint.
(Some of) the extra dimensions which are invoked in String Theory  could also follow the 'monotonic' rule which time follows here/now.

Sophiecentaur

By basing the arrow of time on experience, you're suggesting causality "violations" may be possible. I happen to agree with you. I've suggested in other posts that causality is an operational concept based on the idea of a necessary and sufficient condition. It's an empirical concept, not a mathematical or logical one. Nevertheless, you're treading on dangerous ground when you allow causality violations at macroscopic scales.