Thales

It brings up one of the fundamental philosophical cornerstones of scientific inquiry. That being does anything exist without an observer to observe it and perhaps even more fundamentally what is the definition of an observer. In your above example you do not simply move the mountain towards you, you need to move the entire earth, so as not to displace the mountain from its surrounds. That may seem illogical and inconceivable yet if you place your mind as the stationary point in the frame of reference you are are operating then the entire universe rotates around it, from the earth and the mountain to your limbs and muscles. Your chosen inertial frame of reference deems everything moving relative to you chosen zero point, your brain. It is an equally valid mathematical representation of reality as is choosing the mountain as your 'zero point'. It depends on what you are trying calculate and which frame involves less number crunching. For most basic mechanics problems using the earth as a frame of reference is easiest.

I would like to think of an environmentalist as; Anyone who consciously acknowledges their own personal ecological footprint bought about the way they live their life (be it first world urban living or nomadic hunting) and in turn tries to minimise the adverse environmental effects of their lifestyle choices. Thereby making environmentalism the spread and support of this view, trying to perpetuate an ecological conscience among society.

In terms of concern about performance I believe Chrysler and Smart have created purely electric (lithium-ion) motors and retrofitted them to the crossfire and that small smart car. They have managed to yield better acceleration because the mass of the car is significantly reduced by replacing the heavy mechanical engine with a lighter composite electric one. I haven't got time to google it but I think it was a brain child of MIT...

Any communication sent over the electromagnetic spectrum, in 'open' air, from radar to high frequency mobile phone and wi-fi signals can be intercepted. However depending on the importance of the communication, there are varying levels to which the signals are encrpyted. I should imagine NASA's delusions of granduer would mean these messages are scrambled quiet effectively and thus simply tuning your reciever to the right frequency wouldn't yield much more than noise.

First off, Hello Everyone its good to be back. Secondly, I agree Martin. I have long been a sceptic of infinities in nature. Singularities require gravity to cascade inward, onto a central point, therefore compressing it to an unimaginable size. But all of the other fundamental forces of nature have a threshold scale where their strength/relevence in equations becomes minute or so unimaginably huge that some other force is spawned to stop catastrophy. The limits on the forces of nature, at varying scales, has borne out much of our current understanding. However the use of singularities as a stop gap measure, reaks of the dogma circlulating throughout history, where a god of some sorts was used to explain phenomena which had no other logically obvious means of explianation. The use of a singularity as the boundary at the beginning of time or at the centre of a Black Hole is merely a physicists way of placing the problem in the too hard basket and does little to add to the wealth of Human understanding. Ironically the singularity has alot of relevence in helping to formulate the framework of modern cosmology, as the majority of work is focussed on removing the need for a singularity. So it has served its purpose by flagging any theory that leads to a singularity as incomplete.

The fact that life exists now, the fact that we as conscious beings, spawned from the cosmos who can debate such questions, dictates that life is inevidable. You cannot argue about alternate histories because the gradual progression of time seperates things into too disparte groups. Things that have happened and things that have not. You don't even need to have an infinte universe to insure the emergence of life. The facts I stated in my first post hold true across the expanse of time and space, that does not mean however that they are deterministic, merely that they are invariant. There is a distinct difference. Generally if an emergent property is a possibilty then it has a finite probabilty of occuring. Given the massive data set of the billions of stars and billions of galaxies it seems rather unrealistic to assume that life has not emerged elsewhere. The big bang does explain where we came from, as its intricacies, which we don't understand, set in place the laws which gave rise to us. I don't remember ever saying that we were an accident. I believe we have evolved into our current state as a function of our environment. Our environment and our biology are controlled by physical laws which, as much as you can argue are based on probabilties, are not unique to our corner of the universe. I think you miss understand the crux of my arguement. I believe life is an inevidable consequence of the universe in which we live. I believe that the probablity of humans or human like beings existing elsewhere is little to none as the unique circumstances that led to our life forms have already been actuated thus the probabilty of the exact same conditions being replicated elsewhere is small. I also believe however that biological lifeforms of varying states of evolution permiate the universe. ps. there is a difference between being defensive and retorting in order to support your point of view. Calling somebodies arguement "being defensive" is rather dismissive and contray to the spirit of debate I believe these forums are trying to nurture.

Perturbed? Yes. Support for a lack of life elsewhere? Far from it. Life has been nearly completely oblitrated on earth almost every 250 million years since its conception on earth around 4 billion years ago. It is amazingly resiliant and any arguement that tries to isolate the series of events, that lead to our current level of biodiversity, as unique (in the upmost literal sense of the word) , reflects a lack of understanding of emergent laws such as molecular chemistry and biology. Life is an inevidable consequence of a universe dictated by invariant laws. Why should we be so naive and narcissitic to assume that our little corner of the universe is special?

Jeans Criterion; 2<K>+<U>=0 Basically you need to balance the kinetic energy (K) of the gaseous cloud (which is proportional to temperature ) against the potential energy (U) which in this case is gravitational. A qualative interpretation is that a hot cloud (>K) will need to be denser (>U) in order to undergo gravitational collapse, Alternatively a cooler cloud can collapse more easily (ie over a smaller radius) as it needn't contain as much mass to balance the equation. It is quite easily for us to influence the collapse by either adding matter or by cooling the cloud.

Consider this; -The precursor molecules for primordial life, ie Ammonia, nitrates, water and organic molecules have been shown to exist in comets and if fact it is most likely that comets originally seeded a fertile primordial earth. -The formation of planets is not a unique scenario. We have observed 100's of jovian exo-planets around other stars and with the increasing resolution of space telescopes the discovery of a multitude of terrestial rocky planets is almost assured. -The laws that govern biology on earth exist in these far flung worlds. The laws of nature do not vary as a function of position. -Our current knowledge of life in the universe is restricted to the tiny subset of that which exists on earth. The variety of environments which life could concievably manifest and evolve are not well understood. The prerequisite of liquid water being required for life to take hold seems rather naive. Is it therefore not possible for life to arise in at least one of these potentially habitibal planets? Thats not to say highly-evloved intelligent life exists, but if life exists in at least one of these alternate locations then it must indeed permiate the universe.

Its is my personal belief that infinities don't exist in nature. They are a mathamticial oddity that only arise in our current physical theories because of a lack of undertanding of what happens on the planck scale. If the universe was infinitely big it would contain an infinite amount of energy, which is rather difficult to contain in the supposedly finite spatial dimensions of the big bang. The only thing which may be infinite is time, but even then a cyclical(not nessecarily a simple loop) time line makes more sense than an infinite one. That does not mean that the universe need be bounded in any sense. A being confined to the surface of a sphere can wonder around for eternity but will never find an edge. He is however confined within a finite area.

Explaining away redshift as a function of a galaxies unique position relavite to some universal center is extremely counterintuative and a very unscientific approach. We can tell for instance, by looking at the ratio of redshifts at various distances that not only are these galaxies receding from us they are also receding from each other, thus space is expanding in a roughly homogenous manner regardless of your specific position. It is also isotropic on the largest of scales, meaning that no matter which direction you look you observe the same large scale characteristic structure. Both of these arguements counter the idea of a universal center. As for the contracting universe, it too has flaws. For one we know the time scale of the nuclear burning cycle of stars and by measing the ratio of elements present in the spectra of star we can determine the age of the star with reasonable assurity. There are no stars, whose spectra have been studied, who have a lifetime of more than approximately 14billion years(within a reasonable error). Given there are no stars older than this it is slightly obtuse to assume the universe is much older than this. If the universe had been collapsing under its own gravity for 14billion years prior to reaching its current state then it would have to be larger than it is today by some astronomically rediculous factor. The idea of materialing such a cosmological expanse, into its status quo state and then de-evolving it is rather absurd. The theory works perfectly though if you reverse the direction of time. Funny that.

Forgive my ignorance but I was under the impression that the mars polar caps where mainly frozen CO2, not water ice, which adds weight to the importance of this latest find.

They don't stop sound but they reduce its transmission.

The egg cartons should work a treat. Just cover the offending wall/door. They work by reflecting the waves into the egg holders(squares of card with egg sized dimples) distorting the incoming waves. Alot of people claim they don't work but I have witnessed their effectiveness first hand. The only problem is, to be effective you pretty much need to cover the whole wall. They sound damping effect can be increased if you place foam between the wall and the cartons.

I'm sure I am overlooking something obvious however; Q. Instabilities, of varying frequencies, grow exponentially in a superheated plasma. Controlling these fluctuations is an integral part of successfully harnessing fusion. Is it not possible to harness the increased amplitude of the fluctuations and damp them by an inverting the amplitude of the instability. There will obviously be some delay but surely the feedback loop could be calibrated such that the resulting instability does not destabalise the entire system?