pantheory

Dark matter is needed to support General Relativity, which is the mathematical foundation of the Big Bang model. It is conceivable that another mathematical model of gravity could replace GR in the Big Bang model. Dark Energy, on the other hand, is not needed by the BB model, but its inclusion into the model was thought to be the only explanation consistent with observations of type 1a supernova. Any other cosmological model would also need to explain this same data by a different explanation, or otherwise it would also need to incorporate the dark energy idea. The Big Bang is presently the only considered model in cosmology. When seriously contradicted by observations, the BB model must be able to evolve. When or if it no longer could, it would be replaced. //

All in the field know there is much speculation involved when there is little skeletal evidence. All one can do is listen to what they claim as evidence to support their conclusions and whether it seems like a logical or likely possibility. Evolution over millions of years developed the wolf. Man's domestication of dogs is thought to have been at least 10,000 years ago and many believe much longer. We learned to breed dogs for work and protection qualities so the best dogs became very valuable. In maybe just 10,000 years since we were able to change dogs by selective breeding. Our ability to do this is because dogs sexually mature in 6-12 months instead of 13-15 years old for humans. For the last couple of thousand years there have been few recorded attempts lasting only at most 10 generations concerning the breeding of human slaves for strength and stamina for the fields, and for looks as house servants. Hitler attempted "eugenics" for looks, health, and intelligence, but was stopped after just one generation. So I expect if long-lived aliens wanted to breed humans for some reason, they probably could produce the variety that we see in dogs in the same number of generations which it took us for dogs, which was about 10 to 15 thousand generations of selective breeding. If we get down to understanding genetics better we could breed into animals favorable characteristics in a much shorter time period, with fewer trial and errors, and fewer unfavorable inbreeding traits. Today screening takes place to some extent concerning human amniotic analysis for genetic disease traits which can be selected out by abortion in early pregnancy. //

There is more that one model for black holes. The most accepted definition of a black hole is a small volume where gravity is so strong that matter or light cannot escape from it or pass through it, and therefore it would appear as a black hole in space. The most common definition: A region of space having a gravitational field so intense that no matter or radiation can escape. A mathematical model of a singularity is only one of the hypothetical models concerning a black hole. Dense conventional matter is another model concerning galactic black holes. A third model is a very dense volume of matter like a theoretical neutron star or another more dense form of matter. Some have proposed quark stars, graviton black holes, Higg's black holes, dark matter black holes, and the list goes on. The point is that there is almost a mountain of observational evidence to support the concept of a black hole of stellar size and central galactic black holes of some kind //

Iggy, Got your note on that, and thanks for the link. As you may know I am not a fan of present theories/ hypothesis in cosmology (nor have I ever been). I wrote a paper on type 1a supernovas back in '08' that came up with a different conclusion than the dark energy hypothesis, but I used my own formulations for distances based upon my own cosmological model, which is like comparing apples with oranges. My own analysis comes very close to a change in the data occurring at a redshift of about .6, but my conclusion instead was that they were using a somewhat incorrect formulation (the Hubble formula), to come to their dark energy conclusion. Whether right or wrong, they got the Nobel Prize for it And what did I get for all my hard work? Zilch! (a little tongue in cheek humor). It is rare that a mainstream journal would ever publish a non-mainstream paper I was just hoping //

There are a great many non-mainstream theories that propose and support a flat universe. One of the only theories that does not necessarily predict a flat universe is the BB model, concerning most of its variations. Any theory that uses GR will predict numerous possibilities other than a flat universe. Most theories that either have MOND or another gravity model without dark matter generally must predict a flat universe if space cannot curve or warp. Most, but not all of the alternative flat-universe models are infinite-universe models. Examples are steady-state models of Hoyle and many others. Plasma Cosmology is an infinite model. Some tired light models are infinite, etc. Paul Dirac's expanding matter and space model proposes a flat universe. Most diminution of matter models propose a flat universe, etc. So the idea of a non-flat universe is unique to the BB model or other models that support GR, in my opinion. What sayeth you my friend? //

Iggy, If I'm reading the chart correctly it looks like the beginning of accelerated expansion was at a redshift of about .77 according to the pointing arrow. This would have been about 7 billion years ago, which according to the present BB model age, would have been when the universe was half its present age. Is this the way you interpret the graph? Here's a handy calculator of redshifts vs. time past (distance in light years). http://hyperphysics....tro/hubble.html Most dark energy articles and papers that I have read put this transition time a little sooner than that at a redshift of about .6 which accordingly would have been 6 billion years ago. Of course there is not enough clear supernova data at present to come up with an exact transition time concerning the dark energy hypothesis.

Sounds good. Men could also be part of some bot expeditions as well as moving colonies, especially when/if someday they also have "holidecks," simulated vacation/ holiday spots like on the old Star Trek

I haven't heard it put all together before either. A large moving mining colony could attach itself to a large asteroid with high water content, shield it in the direction of the sun, mine it for water and other valuable on an ongoing basis, breaking water down to hydrogen and oxygen for fuel, air, water for drinking and minerals and water for growing food. With this fuel they could go wherever they wanted in the solar system while continuously being able to re-fuel as needed. Other mined valuables could be sold to a depot in Earth or lunar orbit, for example, and later transported to Earth or any other final-use depot for manufacturing. //

Yes, this is one of the more common interpretations. Most interpret that as a result of Riemann geometry of GR applied to Inflation theory closes the universe like a 4D spheroid with no center to it. One problem with the directional motion of galaxies is that many believe Special Relativity would be violated (exceeding the speed of light), so the presently accepted model is instead that space itself is expanding. Some, or maybe most theorists presently think that accelerated expansion is related to the expansion of space itself. Presently there seems to be no accepted mainstream theoretical separation between the cause of the hypothetical expansion of space, and the cause for its accelerated expansion, other than the names given to it such as "quintessence," and lambda, for instance. //

I think this question is based upon a precise definition of the word "habitable." such definitions of "habitable" are: Suitable to live in; able to be lived in; can be lived in without protection from the elements. There are a great many places in the solar system that I expect we will live in. All must be terraformed for us to live there on the surface without a protective dome. Many of the rocky planets and moons we could eventually live in if we wished to go underground to build colonies, the moon is a prime example. The atmosphere would be manufactured and pressurized, not that hard to do but presently very costly. We could have floating colonies surrounding many planets and moons, again it is a function of cost. We could almost as easily build huge space colonies that could tour the solar system or slowly venture outward to adjacent stars taking many generations or suspend life for the journey as in sci-fi movies. If we're talking about only the surface of the planet/moon as being habitable without protection, then there is only one known place in our solar system, and that's good old Earth. //

There is another requirement that is needed to increase the galactic angular velocity of stars (their orbital momentum). The proposed dark matter orbiting the galaxy would need to have greater momentum than the stars within the galaxy with no explanation concerning how this hypothetical matter got its supposed momentum. If there is no dark matter and instead the orbital-mechanics equation are wrong then one might expect that the lensing equations that predict more matter than we can see could also be wrong since both are based upon GR, and/or that we also have been misinterpreting what we have been observing. //

More observations and studies leading to more doubts concerning dark matter and the standard cosmological model. http://www.ras.org.uk/news-and-press/219-news-2012/2118-do-the-milky-ways-companions-spell-trouble-for-dark-matter

Yes, I think we do. As you might agree, morals can come in many flavors. Atheistic societies taught/ teach their children morals concerning the well-being of the whole society should come ahead of the individual. I think such societies would also make the "proper moral decisions" as in this case. All that it takes, I believe, is educated decisions by those in the field and overseers like the FDA, and most of society will agree. The future always belongs to the brave, and the most timid will always finish last. In western societies an individual's rights and well-being is highly regarding and "the ends do not justify the means," but I think the decisions in this case would be the same: all speed ahead concerning research, and consider all possibilities the best that you can when it comes to application. As the saying goes, "no risk no gain." //

This thread was started as a spin-off from a number of science news articles relating to several studies showing that dark matter does not match predictions of theory, and that it can't be found where it was thought that it should be found, in our solar system.

juanrga, Link removed is a link to a dark matter thread that I just opened based upon a seemingly well written article concerning the problems with dark matter and related theory today, where alternative ideas like MOND and others might be further discussed. General Info: The OP link is not presently working so here's another similar one. http://news-about-sp...luster14637861/

ukgasser, Some of the explanations of quantum mechanics seem counter-intuitive to most people that first study them. Most criticisms of QM do not involve the phenomena or experiment involved, or the maths/ equations being used, only the explanations being offered. Concerning quantum-entanglement explanations of QM, Einstein called this interpretation "spooky actions at a distance," where "magic" would be a similar description //

The link below, I think, is a well-written discussion of the theoretical problems in cosmology today. This topic and thread is for the discussion of these problems. Discuss known alternatives such as MOND etc., or speculate without bringing up too many details of an unknown model such as your own or providing links to such models. For this, your own new thread would be better http://www.scilogs.e...k-matter-crisis

We have lots of evidence that there is something or some influence there concerning the idea of dark matter. But it is only an assumption that it is matter since matter is the only thing that we know of that can increase the effects of gravity. Concerning galaxy clusters, for instance, reformulations of gravity like MOND (in its known forms) also require variable inputs that can be likened to dark matter inputs to Newtonian gravity in the standard formulations. In rare cases, nearly identical appearing galaxies seem to have different rotation curves of their stars. Why should there be different amounts of DM with possibly different DM distributions in "identical" appearing galaxies? but for the same reasoning why should there be different variables used/ inserted concerning alternative equations like MOND? These are some of the questions that are believed to have no obvious answers. // A similar problem seems to exist with expanding space and the expansion of the universe. Expanding space (and therefore the expansion of the universe) is believed to be observable via redshifts of distant galaxies, but it cannot be seen in our neighborhood because it is believed that gravity compensates for it in our neighborhood and in the venue of groups and clusters. The same problem seems to exist for dark energy. I expect these findings of my last link will not be the last word concerning similar studies/ observations concerning possible DM influences in our solar neighborhood, other than those presently being conducted concerning possible evidence here on Earth As a result of such observations/ studies/ interpretations/ conclusions, many still consider dark matter and dark energy as "place holders" until more evidence concerning their nature, or better explanations, theory, etc., might come along. //

The size of the slits are huge compared to an electron. The beam of electrons or photons passing through the slits are directed toward its center. It is thought that no atomic interference can occur. I would expect the material being used is non-magnetic and maybe nonmetallic materials involving no net charge. General Influences of the sidewalls of slits for these reasons, are thought to be non-existent or negligible. De Broglie believed that both waves and particles have a physical reality. He explained that he saw no mystery at all in the double-slit experiment and was surprised that others considered it a mystery. When two slits are open but an electron goes through just one slit, the physical waves produced would go through both slits and interfere with each other and the particle producing the observed patterns. The same explanation would apply to photons. Most did not accept his very simple explanation since physical waves would seemingly involve an aether. In today's physics there is no such thing as a signal without a wave or particle being involved. The idea of pure radiated energy involves waves. I agree that either a particle or wave, or both could seemingly cause the photo-electric effect, but in present theory photons alone can do this based upon Einstein's related equations which propose discrete light particles (photons), that accordingly predict the observed results. //

I have had at-length discussions on this subject with the mathematician and physicist Michael Minovich some 30 years ago or longer and more recently. He is the person who developed the original gravitational whip concept and calculations for NASA, which we have used ever since. You are correct in that by entering a gravitational field an object accelerates, and by leaving the system it loses this gained speed, with no net gain. The whip advantage instead comes from planetary momentum so a craft would enter the gravitational field in the direction of its planetary velocity around the sun and could leave the system in a hyperbolic passing with a net gain in velocity. The best planets for this procedure are Venus and our own planet because of both their mass and planetary velocity/ momentum. Mercury is distant and relatively small although its momentum is faster. Mars is both smaller and slower than Earth or Venus. And the outer planets although bigger, move much slower in their orbits providing a lesser gravitational assist than Venus or Earth could. For the larger planets the direction of their rotational velocity and the distance of approach is another consideration concerning a better whip or braking. As far as an assist from the sun, when our spacecraft fly inward toward the sun they will accelerate. As they get a gravity assist from an inner planet they increase their speed again by this whip, but when flying away from the sun they lose this first advantage of accelerating inward. So the sun does not help or hurt. Gravity assists are also used for braking. When flying to the planet Mercury both Venus and the Earth can be used for braking when doing its flyby in the opposite direction of the planetary momentum. This braking system could have been used concerning Neptune, for a small fuel saving braking maneuver when settling into orbit around its moon Titan. I have read some online explanations of these procedures that seem authoritative but are completely wrong concerning their explanations http://en.wikipedia....chael_Minovitch http://www.gravityassist.com/

Saw this in the online news today. Very interesting concerning all kinds of possible applications in medicine, and possible biological applications galore, besides probably in the foreseeable future, the creation of man-made life. // //

In the 17th century Newton proposed light as being particles based upon his corpuscular theory and model. Huygens then followed with his wave theory of light toward the end of the century. Although Newton's model prevailed for about 100 years eventually the bulk of theorists eventually adopted Hoygen's model because the corpuscular model failed to adequately explain the diffraction, interference and polarization of light, and because of new evidence concerning the wave nature of light revealed by Tomas Young concerning his double slit experiment and other experimenters of the 18th and 19th century. It wasn't until the late 19th century and the early 20th century that the idea of light as a particle was again postulated by Max Planck which he called quanta (as in Quantum Mechanics) and Alberta Einstein who called the same proposed particles photons. The idea was that since they could not find an aether to carry the waves of EM radiation, they proposed the idea of waves of pure energy having no medium at all. To explain the particles/ quanta/ photons they proposed particles moving through generally empty space between stars, and later between galaxies. Theory evolved that depending on the observers point of view, light could be considered a particle or a wave, but not both at the same time. This is the present view which is based upon interpretations in Quantum Mechanics with the realization that atomic and other quantum particles also have a wave nature to them as shown by De Broglie. So present theory is based upon the evolution of Quantum Mechanics of which this assertion of the duality of EM radiation is one of its foundation pillars. Although there are many new and modern aether theories, most theorists still are not interested believing that the aether was long ago disproved. If we ever discover an aether as "the medium in which the process occurs" (in your words) then at that time we might consider that EM radiation is both a particle and a wave at the same time. Maybe ideas like the particles/ photons are produced by the waves and are surfers within them, or that light particles as they move in groups at a given frequency, push up the waves, or other such ideas. But presently such ideas are not ever considered by mainstream theorists is Quantum Mechanics since there seemingly is no present reason for such speculation. Based upon your doubting statement, I too also think there are flaws in present logic of Quantum Mechanics concerning this and other interpretations, and so did a great many other theorists such as Einstein, De Broglie, Schrodinger, etc. The formulations were not in question by them, only the logic concerning why the formulations should be valid. Einstein believed QM was merely a predictive system of statistics and equations formulated to match observations. Heisenberg, Born, Wheeler, and others believed the system represented a fundamental character of nature at the quantum level proposing such things as probability waves concerning no actual exact physical location or momentum of particles in motion, as well as wave particle duality of EM radiation, etc. The answer to most of your questions can be found in QM theory (whether present interpretation may or may not seem to have logic to it), and other questions you have asked have various possible QM mainstream answers or interpretations. http://en.wikipedia....antum_mechanics //

There is mounting evidence that dark matter is not conforming to any well-known dark matter theories. Although most still believe there is much evidence to support the idea that there is something there that may behave like matter there still is no evidence for its character, or even to say for sure that it is matter -- see the science news section of this forum concerning -- is dark matter really matter? Most would agree that at least it is a placeholder for something that we still don't understand. Dark energy is also just theory. The Nobel Prize was recently granted for its discovery but it too may be only a placeholder for something still not understood concerning what it is. There are a great number of hypothesis concerning both of them but the related observations are often not confirming the related theories. Once you read the Wiki pages on both you can understand present ideas of them concerning their educational value. Beyond that ideas can be quite speculative. //

I've read such things also. But you probably realize that ideas of what is happening near, at, or inside a black hole's event horizon is theory at best, and often just speculation. Near the event horizon where a accretion disc and torus can be observed, speeds can approach 10% the speed of light by observational calculations. It is thought by many or most theorists that at these speed within a torus that molecular and atomic ionization will first occur. Following this friction would bring about molecular disintegration. Following this the resultant atoms would probably remain ionized and the tidal forces at or inside the event horizon are thought to be able to cause spaghettification, being the linear stripping of atoms down to primarily nuclei and electrons (pasma). In active galaxy nuclei (AGN) of galactic black holes, even the atomic nuclei could be further fissioned down by the heat and compression into the lightest nuclei providing the energy for polar galactic jets in such galaxies. This is one proposed model. There are few theoretically passive models like the one you read, to my recollection, that would allow a passive transition of a spaceship, for instance, through the event horizon unscathed. //

Maybe with stereoscopic (or other) imaging methods and programming, such imaging translations might be better than an ultrasound image, I would hope //