MigL

Make all the river analogies you want as no-one ever said time WAS a river. Just like an electron is not a small aphere or a wave, but it can at times act as either depending on the type of experiment, so will time act like a river under certain considerations. However what 'flows' is actually the 'now moment', at one second per second usually, since all events in space-time are fixed, past, present and future. This 'now moment' is like a vertical slit moving across a window pane as it moves foreward in time and the view changes ( we remember the past but have no recollection of future events ), however it moves foreward at differing speeds along the length of the slit due to differing conditions and the finite speed of light ( there is no universal now ), just like river currents are different due to differing conditions in the cross-section of the flow. This is just an opinion of course, but you do see how difficult it is to describe complex phenomena like time using simple, everyday analogies ?

As simply as possible... Draw a space-time diagram where the X-axis denotes position and has units of 300000 km, and the Y-axis represents time with units of seconds. A vertical line such as X=constant, indicates stationary position. A horizontal line, Y=constant, indicates stationary in time. Note that a light cone has, in this instance, a V-shaped slope of +/-1 ( 45 degree ), and while a vertical line is perfectly acceptable, a horizontal one is NOT since it falls outside the light cone and implies FTL motion. As swansont and elfmotat have hinted at, this applies to events and frames where v<c, not to massless particles such as photons where v=c.

Are you sure about that Michel123456 ??? Its possible ( in some specific cases ) to be stationary in space. How would you go about being 'stationary' in time, then ???

So how do you assume stars form Dekan ????? And for that matter, given sufficient gravity, the electrons of an atom, even hydrogen, are forced into the nucleus ( or proton ) to form neutronium. Or how do you assume neutron stars form ??? And have you never heard of the strong nuclear force ???

Really, John C., how dare you inject a modicum of common sense and knowledge into this fairy tale that these ' gravity pushes' adherents are peddling, Don't you know that their unsupported statements are more valid than your statements supported by accepted scientific facts ? Really, when I need a good laugh, I read the speculations forum. Its better than reading Lewis Carroll, nothing makes sense. And they cannot be convinced.

Oh, come on !! A little thinking before posting goes a long way.

Do all stars really ignite at the same temperature, or pressure, as has been suggested ? I would think the make-up of a star would be a big factor. A blue giant as opposed to a red giant, population I as opposed to population II, hydrogen rich as opposed to helium rich, or spiral arm location as opposed to galactic core location. A core with a high percentage of helium will require a much higher temp to ignite and I would assume, as a result, that red giants would be much more common than blue giants.

I don't recall being taught that in any of my quantum mechanics courses !

Do you know what Quantum Field Theory, QFT, is ? It accounts for your quark/gluon interactions and is known as Quantum Chromodynamics. Look it up.

Don't follow your reasoning, splitinfinity, to put it mildly. Both GR and QFT make do with four dimensions and do an adequate job of explaning reality except for areas where they overlap. I wouldn't say that any more dimensions are necessarily needed. Strimg/M-theory uses 7 compacted dimensions along with the usual four, but its along way from making any verifiable predictions and dark energy is another name for the cosmological constant as a result of vacuum energy

We actually know quite a bit about dark energy. We know, for example, that it acts very much like Einstein's cosmological constant and is related to vacuum energy ( what you refer to as space or nothingness has very distinct properties ). The universe is not expanding into anything, as a matter of fact universe means everything there is. It does not matter if finite ir infinite as long as it is unbounded, otherwise you'd have to explain what's on the other side of the boundary. A sphere is finite in size but you can travel forever in any direction, ie its unbounded. Alternatively a sheetof infinite size is also unbounded for the same reason. The separation between objects in the universe ( on a scale where gravitational interactions are overcome ) is growing. That is what is meant by universal expansion, and yes, this separation growth can be superluminal. It is by no means an explosion of 'stuff' into an empty 'void'. But back to the OP... The singularity is nothing more than an indication that GR's field equations become 'undefined' at that point, ie. they are no longer a valid or sufficient description of reality. A theory which takes quantum behaviour into account is needed. See string/M-theory or Loop Quantum Gravity for some current efforts on that front. So yes, the possibility of not having a singularity are probabily very good.

You guys need to look up the definition of an inertial frame. A frame where you speed up to near c and then decelerate to 'sync-up' with earth's frame is not only NOT an inertial frame, but is also a different frame. Rule #1 of relativity: Do not mix frames ( as Swansont has pointed out several times now ).

The last emitted light from the big bang has overtaken the expansion of the universe already ( universal expansion only outpaced light during the inflationary phase ). It did so about 13.4 billion years ago, but since the universe has been expanding, this light has been shifted into the microwave region of the spectrum. We now call it CMB radiation, and it is 'visible' anywhere in the observable universe.

Only bound neutrons are stable Timo. Are you suggesting Higgs bosons may also have bound states? A more accurate statement by Mathematic would have been '' dark matter consists of particles that are DETECTED only by gravity", as they are undetectable EMR and the other interactions are short range.

Electronic 'noise' is the biggest detriment to using small digital ccd/cmos sensors and small pixel size. There are always stray photons impacting the sensor, even infrared or ultraviolet. That's why the better digital SLRs use aps c or full size sensors, and can image at up to ISO6400 with no noise, while the small 'throw-away' digicams are noisy even at ISO800. Think of the sensor pixels as buckets, and light as drops of rain. If the bucket is very small, its very difficult to tell how hard its raining ( light intensity ) because even a stray drop of water will fill the bucket.

I would point out that a ruler can be subdivided indefinitely into smaller and smaller intervals such that an infinity of them would be constituted of zero size points. This does not mean that the ruler is a point. It has a definite length. The same argument can be made for the 4D contiguous manifold of space-time. As AJB points out however, certain theories like LQG, describe small scales without using contiguous points.

Don't put the cart before the horse, Sam. The Higgs mechanism involves the interaction of a scalar field, which AJB has already explaned. This field is, in effect, a false vacuum energy level throughout all of space ( to put it simply ). As a quantum field, it will have, by necesssity, fluctuations which manifest themselves as Higgs bosons. Sorry to hear you won't be posting as much AJB.

I made this point in the speculations section and was told by Moontanman and Ophiolite that I'm wrong. Now the last Biology class I took was Gr 10 in !974 so I'm not even an amateur, but I would certainly like to know why I'm wrong. It seems to me that even though the rate of mutations remains constant for an advanced civilization, the process of natural selection ( by the environment ) is no longer valid as the advanced civilization can modify/alter its environment such that no trait has an advantage and is ( naturally ) selected. This is a very simplistic example but bear with me. Consider two monkeys, one with good eyesight and one extremely myopic, living in the trees. As they jump from branch to branch the myopic monkey misjudges distances, and falls to its death. It will never pass on its elongated eyeball, myopic gene while the monkey with good eyesight will. Now assume these two monkeys develop an advanced, intelligent civilization and learn to grind glass lenses. The myopic monkey is now able to wear glasses ( or even contacts ) and will not have a disadvantage for natural selction and survives its environment, hopefully to reproduce and pass on its elongated eyeball, myopic gene. Intelligence or more accurately the ability to alter the environment which does the selecting, effectively put an end to natural selection, which is the basis for passing on selected genes and evolution as we know it.

Deductive reasoning may be used in court cases Moontanman, but as a system of logic it does have a flaw. As pointed out by Godel, certain self referencing algorythms result in non-sensical logic. What do you deduce from "This statement is false". But seriously, at the base of evolution is mutation, whether good or bad is determined solely by environment, This is where the oft quoted ( but not quite accurate ) statement "survival of the fittest ( for that specific environment )" comes from. And I don't think there's doubt in anyone's mind that good and ( mostly ) bad mutations do happen all the time. They manifest themselves in the abnormal ( is there a normal ? ) DNA structures leading mostly to deseases and cancers. Sometimes they lead to abnormalities like webbed or 6 toes or fingers; unfortunately there is no advantage to such a mutation in our environment. As a matter of fact, one could argue that a sufficiently advanced species such as ours is able to affect or modify the environment we inhabit to suit us and have no need to evolve futher than the current 'norm'. So forget about the big bulging heads and childlike bodies with atrophied muscles of science fiction, we have effectively stopped evolving.

A singularity is by definition a singular point, ie dimensionless,and although mathematically possible, most certainly unphysical. There is no varying sizes of singularities EWyatt, and yes, energy gravitates.

I'm sure composite systems like molecules certainly, and atoms probably, have actual rotations ( observationally constrained by the HUP of course ). Elementary particles, however, have only intrinsic QM spin, which is not a rotation as elementary particles are considered dimensionless points. Just as you would consider e the quantum of charge and h-bar the quantum of energy, consider h-bar/2 the quantum of angular momentum.

As AJB has said, 'force carrier' is somewhat of a misnomer, A boson is a manifestation of a quantum field, of which there can be several classes, scalar, vector and tensor. Familiar fields have energy and a vector direction A Higgs field,on the other hand, is a scalar field, having the energy associated with a field but no direction. Can you have a force without a direction ? I don't know about mathematical links, but physically the Higgs field is linked to false and actual vacuum energy levels attained through various spontaneous symmetry breaks for our domain of the universe ( see electroweak unification ) .

I assume AJB could better answer your question. The Higgs field is definitely scalar, ie directionless, but a Yukawa coupling or interaction ( as in the interaction between nucleons by exchanging Pions ) is, to my knowledge, directional.

They are both manifestations of their respective quantum fields. Other than that, I don't know, what is the relation between a photon and a gluon ?

I think you mean to say AJB, that a space which is not simply connected has holes in it and loops cannot be fully contracted. A very simple example ( 3D only ) would be a doughnut shape. Consider the inside curve of the doughnut, it has negative curvature, while the outside curve has positive curvature. Now if you are standing on the surface of the doughnut between these curvatures, you will notice that turning to one side by a given angle is not equivalent to turning to the other side by the same angle. There is no rotational symmetry, and that is a problem for conservation of angular momentum.