pantheory

I think it is one of the possible but highly improbable beginnings of life, human life, intelligence, etc .; I think 1 in a million would be giving this possibility to much credence.

I just took a quick look at your site. Cool! Mine is pantheory.com It appears that we both have a book in cosmology and plenty of related ideas. I'll read more of your site as time permits, Regards, Forrest

Md65536, "I don't have a firm handle on curvature but I think curvature due to mass approaches 0 (flat) as distance approaches infinity, but it is still non-zero at any arbitrary distance???" Yeah, that sounds right to me according to the warped space model, that matter warps the space surrounding it and is the cause of gravity. " ... there is an intrinsic limit to distance based on time (concerning gravity). A mass cannot have any effect on anything outside its light cone." (parenthesis added) This is also valid but indirectly there is a gravitational effect of everything on everything else. The idea is that although it is outside your light cone now, for instance, it does and did effect its neighbors, which effected its neighbors, and so on, all the way back to you. If something is outside your light cone but could somehow disappear, then according to GR it could never effect you because its effects could not travel faster than the speed of light. "That spacetime warps (consistent with SR and GR) is a fact of reality that I accept." The warping of space (space-time) is unrelated to SR which says nothing about this. It is strictly a GR proposal. But of course the concept does not violate SR. "...I don't think that all these beliefs are mutually consistent, and I'm missing some understanding of the meaning or implications of curvature..." As to the meaning of flat space: it is what we see in the everyday world. It's the way other animals see the world. It is simply a three dimensional structure of reality which is the natural way that it appears to be to the unaided eye. It was the reality of physics up until Einstein proposed it differently. Remember, there is no evidence of any kind that I know of, that space is curved. There is evidential support that gravity works in a non-linear fashion, not strictly according to the inverse square law of Newton. As to curved space: In Riemann geometry which is the geometry of GR, two parallel lines can eventually cross. There is no forth dimension involved (other than time) so that it is a type of non-linear geometry which Riemann said did not apply to the natural world, yet Einstein found an application of it in the equations of GR, whether right or wrong. If space is entirely flat at the largest scales of the universe, then at least the warped space/ curved space idea of Einstein is wrong. All observations so far seem to indicate that at least the observable universe appears to be flat.

gillian, Even if clusters are huge gravity wells and that escaping light from them are bent, does not mean that intelligent space craft would have to follow this course. Like from Earth to orbit the most efficient way to orbit to save fuel is to follow a circular path into orbit. If fuel was not a concern you would just go straight up and away like sci-fi UFO's. Some day I believe we won't waste the time with circular paths to orbit or to go out and about

Of course some consider that speciation is still debatable. It is at the heart of evolution just following natural selection. I suggest you read as much as you wish on the subject. As for myself I have seen lots of great examples/ evidence for it but don't wish to spend the time to find the links at this time. Hopefully, for your questions sake, others will do so. If not later I might look for the examples that I aware of. There is lots of evidence that some of the animals within the same genus can bread together, lions and tigers, whales and dolphins, horses and donkeys, etc. One of the definitions of speciation, with lots of exceptions like the ones given, are that animals in different species no longer can bread together. In the cases given, some of the off-spring are fertile and some are not. It is not a point to be argued IMHO unless you are educated concerning "examples" of natural selection and speciation which would require at least several days of investigation on the net IMO. Obviously there are no "certain" examples that are beyond argument, but it's easy to draw logical conclusions from the evidence that speciation exists IMHO. The problem is that it usually takes millions of years to occur and is more rare concerning members of an evolving species when both species are alive. Realize that speciation does not necessary mean that the species that started the speciation has died off although that usually is the case. Speciation is also not thought to always be linear or based upon natural selection. An example would be a virus or bacteria getting into the DNA of a living animal and its embryos. It could in one step modify the offspring to the extent that it would not be better adapted but might be equally adapted. This "new species" might prefer breading with each other and may not be able to bread with members of its original species. There are many man-made examples of creating divergent individuals using foreign DNA.

Md65536, ".....It seems that if space is flat (infinite) and homogeneous and isotropic then an abstract definition of distance would match a real definition of distance? Then, even if we couldn't measure distance in nothing without putting something into it, we could extrapolate it. This relies on the assumption that spacetime curvature is homogeneous to an infinite distance in any direction, which kinda implies that infinite distance is defined. I'm confusing myself now, but there must be something in this statement. Matter causes spacetime curvature at a distance. That curvature can be measured or extrapolated. Or is spacetime curvature the same as distance, and could be argued to have no meaning except between given reference points? Without figuring out the meaning of nothingness or space, I would guess that the calculable effect of spacetime curvature caused by mass would allow for a definition of distance, and this curvature is defined within the light cone of that mass......" (your quotes above) IMHO you are definitely thinking logically concerning these quotes. your quotes: "...I'm confusing myself now..." ..."I've talked myself in circles.." The problem you are confronting I believe is. If space is totally flat (or spacetime if you prefer) then it does not warp; there is is a contradiction. Einstein proposed that space "warps" (bends) but based upon the Hubble space telescope, space appears to be flat. Most of those who continue to adhere to the warped space concept believe that in the grand scheme and outside the observable universe, that there is a curve (a small angle of warp) to the universe that we presently cannot observe. This is required by General Relativity (GR) based upon Einstein's explanation for using Riemann geometry in his equations. It could also be that his equations are right or partly right but that space does not warp or bend. You also mentioned gravity waves. Of course it has not been proven that gravity waves exist but there is evidence that they might, and a Nobel Prize given for the evidence to suggest them. If they exist then, the question becomes, "what do they do." Some think that they are the cause of gravity but in GR, gravity is caused by warped space. Others including myself believe that gravity waves are simply waves produced by very massive objects and are unrelated to gravitational effects. They are more like De Broglie waves IMO. So my point is that if you take warped space out of your thinking then it will make more sense to you IMO, at least as far as this thread is concerned. Another point concerns your idea of infinite space. If space is defined by matter as in the BB model or other finite universe models and Einstein (according to his quote in the O.P.), then space is not infinite by definition. I agree.

You are on to something. I think your thinking is correct. I just made a posting in the "What is space" thread started in 94. What I said there is what I will say here to you and I think not different from what you assert. Space can properly be defined as the volume that matter occupies. Linear space can be defined as the distance between matter, where matter is the yardstick. As Rene Descartes put it, space is an extension of matter. "People before me believed that if all the matter in the universe were removed, only space and time would exist. My theory proves that space and time would disappear along with matter" Einstein. Einstein had a lot of great quotes and this is one of them. What would be the meaning of space or time without matter. Space requires extension and time is simply an interval of change in matter. Any other meanings for either seemingly would make no sense.

Howdy all, I'm from California and have spent a lifetime studying physics and cosmology. I am an alternative theorist and have written a book and technical papers concerning alternative cosmology and related theoretical physics. The model that I propose is now more than 50 years old. I have broad interests in science along with many other subjects. I enjoy a good discussion on the net but in my experience arguments on the net do not bear fruit . I am not married but have adult children ages 30 to 34. I am of retirement age but have several on-going businesses. One is in construction, another is in stem cell research. I have been a science teacher in science and technology. I am always looking for science minded readers who would read and criticize my theoretical/ cosmology book or related new technical papers. I like to make friends so give me a holler. Presently my friends run the gammut of ages form early twenties to 85 for my best friend. best regards, Forrest

Wow, this is a long, old thread but a very good question. Where does space end? I think it comes down to the definition of space and there is no consensus concerning a definition. I agree with those Big Bang theorists who assert that both time and space were created from the beginning of the universe, and there is no such thing as before that. In the same way the meaning of space could be defined as the volume that matter occupies concerning its volume, or two dimensional space could be defined as the distances between matter. This I think explains the question. Space extends as far as matter extends. As Decarte proposed, space is an extension of matter. Beyond this meaning I believe philosophy begins. Such a question would be: what would be the meaning of space outside the bounds of all matter and field, or similarly what would be the meaning of time if nothing existed that could change?