beecee

Hmmm, it appears you have a chip on your shoulder...or perhaps an agenda? And yes, it has now been experimentally shown that gravitational waves do propagate at "c"

I do not believe that is the case...of course if you have a reputable citation then give it. Hawking anyway of late, simply appears to be hypothesising on EHs, quantum effects and firewalls. None of that invalidates BHs despite some past mis-leading, sensationalistic headlines. Secondly, there is really no absolute truth in science. So far GR has past every test thrown its way, and has made successful, validated predictions. I don't accept your baseless claim that not everything is correct as far as we know, according to GR. At least at this time. As I said, with regards to Hawking, his hypothetical is with regards to the EH and quantum effects and does not invalidate the GR BH concept. But of course I will listen to any reputable citation from any reputable expert that says the stuff about BHs as dictated by GR, is of no more value. In absence of any reputable citation or reference, I see your claim as a fairy tail. Sheer speculation at this time. BHs are now overwhelmingly accepted and evidenced particularly after recent observations. As far as I know, and I'm willing to be corrected, the BH is a solution of the equations of GR...so tell me, why then would you not apply GR logic?

Every person is entitled to his or her own opinion/s, but not their own fact/s.

https://academic.oup.com/mnrasl/article-abstract/474/1/L81/4566532?redirectedFrom=fulltext Formation of precessing jets by tilted black hole discs in 3D general relativistic MHD simulations: Abstract Gas falling into a black hole (BH) from large distances is unaware of BH spin direction, and misalignment between the accretion disc and BH spin is expected to be common. However, the physics of tilted discs (e.g. angular momentum transport and jet formation) is poorly understood. Using our new GPU-accelerated code H-AMR, we performed 3D general relativistic magnetohydrodynamic simulations of tilted thick accretion discs around rapidly spinning BHs, at the highest resolution to date. We explored the limit where disc thermal pressure dominates magnetic pressure, and showed for the first time that, for different magnetic field strengths on the BH, these flows launch magnetized relativistic jets propagating along the rotation axis of the tilted disc (rather than of the BH). If strong large-scale magnetic flux reaches the BH, it bends the inner few gravitational radii of the disc and jets into partial alignment with the BH spin. On longer time-scales, the simulated disc–jet system as a whole undergoes Lense–Thirring precession and approaches alignment, demonstrating for the first time that jets can be used as probes of disc precession. When the disc turbulence is well resolved, our isolated discs spread out, causing both the alignment and precession to slow down. Here is an article from "Universe Today" https://www.universetoday.com/138247/astronomers-figure-black-holes-can-blast-relativistic-jets-material-across-light-years-space/ ASTRONOMERS FIGURE OUT HOW BLACK HOLES CAN BLAST OUT RELATIVISTIC JETS OF MATERIAL ACROSS LIGHT YEARS OF SPACE Black holes have been an endless source of fascination ever since Einstein’s Theory of General Relativity predicted their existence. In the past 100 years, the study of black holes has advanced considerably, but the awe and mystery of these objects remains. For instance, scientists have noted that in some cases, black holes have massive jets of charged particles emanating from them that extend for millions of light years. These relativistic jets” – so-named because they propel charged particles at a fraction of the speed of light – have puzzled astronomers for years. But thanks to a recent study conducted by an international team of researchers, new insight has been gained into these jets. Consistent with General Relativity, the researchers showed that these jets gradually precess (i.e. change direction) as a result of space-time being dragged into the rotation of the black hole. Their study, titled “Formation of Precessing Jets by Tilted Black Hole Discs in 3D General Relativistic MHD Simulations“, recently appeared in the Monthly Notices of the Royal Astronomical Society. The team consisted of members from the Anton Pannekoek Institute for Astronomy at the University of Amsterdam and a professor from the Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) at Northwestern University. much more at link.................

http://www.preposterousuniverse.com/blog/2013/10/18/is-time-real/

The evolution of life is entirely a scientific explanation based on observational data, that is as certain as any scientific theory can be. Science does not deal in proofs, but as you have already been informed, evolution is for all intents and purposes, certain. . A total nonsensical statement. Galileo for example showed that the church supported geocentric model was false. Since then the earth has been shown to be simply a planet orbiting a humdrum star, in the outskirts of a average galaxy among billions of other galaxies in the observable universe. While evolution maybe a fact, Abiogenesis is the only scientific answer as to how life started. No labels such as "atheism" needed, it is simply logical conclusions, based on observational data, and the application of science, without which we all would still be swinging in the trees.

Yes, that's because as any particle approaches the EH, it is continually accelerated to speeds approaching "c" but never quite reaching "c", thereby leaving open the chance of possible escape. With polar jets for example, it is thought that these occur with rotating [Kerr] BHs, where matter possible interacts with magnetic fields near the BH, and creating the jets that we observe.

Firstly gravity is spacetime, which evolved from what we know as the BB. Having come in late in this thread, let me say with utmost certainty at this time, cosmologists do not know how or why the universe came to be. But they can reasonably speculate....I like the following reasoning. https://www.astrosociety.org/publication/a-universe-from-nothing/ Let me add that perhaps your definition of nothing should be revised, as hinted at in the extract from the above..."What produced the energy before inflation? This is perhaps the ultimate question. As crazy as it might seem, the energy may have come out of nothing! The meaning of “nothing” is somewhat ambiguous here. It might be the vacuum in some pre-existing space and time, or it could be nothing at all – that is, all concepts of space and time were created with the universe itself" "Quantum theory, and specifically Heisenberg’s uncertainty principle, provide a natural explanation for how that energy may have come out of nothing. Throughout the universe, particles and antiparticles spontaneously form and quickly annihilate each other without violating the law of energy conservation". Obviously the universe being the "ultimate free lunch" at least to me, appears to be the only real answer in the absence of as yet, any evidence. Much the same way as Abiogenesis is really the only scientific answer as to how life came to be. Just because at this time we have no empirical evidence of where the universe came from [other then the BB and spacetime as we know it] does not mean that there is no logical explanation. I just gave you a link to one. Then you are saying the universe came from nothing, which is illogical. On face value and to a lay person that may seem illogical. But to a professional scientist, there certainly is logical scenarios as to how the universe came to be. It's your definition of nothing that needs reappraisal.

https://phys.org/news/2018-01-space.html By shining a laser along the inside shell of an incandescent light bulb, physicists have performed the first experimental demonstration of an accelerating light beam in curved space. Rather than moving along a geodesic trajectory (the shortest path on a curved surface), the accelerating beam bends away from the geodesic trajectory as a result of its acceleration. Read more at: https://phys.org/news/2018-01-space.html#jCp :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: the paper: https://journals.aps.org/prx/abstract/10.1103/PhysRevX.8.011001 Observation of Accelerating Wave Packets in Curved Space ABSTRACT We present the first experimental observation of accelerating beams in curved space. More specifically, we demonstrate, experimentally and theoretically, shape-preserving accelerating beams propagating on spherical surfaces: closed-form solutions of the wave equation manifesting nongeodesic self-similar evolution. Unlike accelerating beams in flat space, these wave packets change their acceleration trajectory due to the interplay between interference effects and the space curvature, and they focus and defocus periodically due to the spatial curvature of the medium in which they propagate. <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> OK, a couple of questions....Firstly the article: What do they actually mean by "accelerating light beam"?? Is this more a reference to the coordinate speed of light? Secondly, what do they actually mean by "bends away from the geodesic trajectory"?? With regards to the paper, I believe they are rather sloppy with reference to the three highlighted phrases. Should they not be referring to spacetime? Any other comment?

I think the answer to that is the same as the answer to what caused the BB. We don't know. The way I view the whole picture [I may stand to be corrected on this issue] is that just after the initial BB or a part of it, Inflation took part. The density of the universe at that time saw the incredible rate of inflation gradually slowed to a more sedate pace, until a period was reached where due to the continued, albeit slowing expanding rate, the density eventually dropped to such a figure, that the large scale expansion rate again took over and we observed an acceleration. This is where we find ourselves now.

The expansion of the universe is only evident over larger scales. Over smaller scales, say our local group of galaxies, the gravity of the mass energy within such regions, overcome the expansion we observe over the larger scales. And even smaller scales will see the EMFs and strong and weak nuclear forces overcome the observed large scale expansion. That explains why planets, stars, us etc are not affected by the expansion of spacetime over larger scales.

The crux of the matter is simply once any matter/energy crosses the EH into the BH, it only has one path to follow, and that is towards the center [singularity] Any "burping," any polar jets, all actually emanate from matter/energy before it crosses the EH. Even the concept of Hawking radiation does not entail any particle crossing from inside to outside. That could be said to be the first rule/edict of BHs.

I would say because Uranus is less dense.

No probs...As has been said many times, a whole new region of cosmology opened up for scientists, The mind boggles!

I once heard Stephen Hawking make a similar comment. From memory it was at a Millenium function at the White House at the turn of the century, year 2000 or 2001. I remember it was hosted by the President Clinton. Agreed.

The above facts are continually avoided by those with other agendas, or any unscientific notion of ID. While it certainly maybe possible that life on earth was intelligently designed by some advanced Alien lifeform, the obvious next question is how this advanced lifeform/designer came to be. In other words getting down to the nitty gritty, one cannot but conclude with near certainty, that Abiogenesis is the only scientific answer available to us.

Any star will have its "goldilocks zone" or that region where water can exist in liquid form on the surface. Although I'm pretty sure that having the ability to have liquid water exist on the surface, is not the only criteria for life. With regards to a "super Earth" "habitabity", while agreeing that it may even be better suited, perhaps any evolution of intelligent life, would take much much longer to overcome the extra force of gravity that once bound us to our Earth.

The hypothesis re the supposed necessity of our Moon, never really grabbed me at all. I think from memory, part of the reasoning was that the comparitively large Moon, helped stabilise the Earth's rotation about its axis to the few degrees we do experience and is apparently responsible for the Ice ages. Without it, so the hypothesis goes, Earth's tilt would have varied by much more, creating catastrophic conditions that would be unsuitable for life as we know it. And of course we don't see that sort of reaction with the Pluto/Charon system, where the size of the Moon in comparison to the planet, [oops, sorry, minor planet ] is much closer aligned then with Earth and our own Moon. Totally agree. Perhaps...but as I suggested earlier somewhere, it wasn't really so long ago that the Earth was not only the center of the galaxy, the MW galaxy was the only galaxy, and was the center of the Universe. We have come a long way since those days of course, and the continuing discoveries of all sorts of extra solar planets, around a myriad of different stars, points to the scientifically support edict, that the Earth, [other then being the only place we positively know of supporting life] is nothing special at all. I do believe though that discussing extra solar planets, particularly the ever increasing numbers of verified candidates, that ETL is bound to be raised. I also totally agree with your other summation re the eventual discovery of life off this Earth within our own system, as also it appears do many cosmologists in this day and age. When that does happen, I would venture to say that it will raise the question of Panspermia, of which I sort of lean to...but that also is the subject of another thread.

Some interesting, if obvious points re the article...... https://phys.org/news/2018-01-gravitational-universe.html "Knowing how far away it is and how fast the galaxy is moving from us allows scientists to calculate the time since the expansion began – the age of the universe: between about 11.9 and 15.7 billion years given the experimental uncertainties". and...... "The age derived from this single event is consistent with estimates from decades of observations relying on statistical methods using two other sources: the cosmic microwave background radiation (CMBR) and the motions of galaxies" "With a large statistical sample of gravitational wave events of all types, the current range of values for the age will narrow". "Although both the CMBR and the galaxy measurements are each quite precise, they seem to disagree with each other at roughly the ten percent level. This disagreement could just be observational error, but some astronomers suspect it might be a real difference reflecting something currently missing from our picture of the cosmic expansion process, perhaps connected with the fact that the CMBR arises from a vastly different epoch of cosmic time than does the galaxy data. This third method, gravitational wave events, may help solve the puzzle".

Your first mistake is your "argument from incredulity" fallacy. Your second mistake is that as you have been shown now many times, space and time are actually variable and it is the speed of light which is constant. This is now well and truly beyond any reasonable doubt, and has been confirmed many times and continues to be confirmed every day.

Gravitational waves measure the universe January 8, 2018, Harvard-Smithsonian Center for Astrophysics NGC4993, the galaxy hosting the gravitational wave event GW170817 that has been used to measure the age of the universe. The source of the event is the red dot to the upper left of the galaxy's center; it was not there in earlier images. Credit: NASA and ESA The direct detection of gravitational waves from at least five sources during the past two years offers spectacular confirmation of Einstein's model of gravity and space-time. Modeling of these events has also provided information on massive star formation, gamma-ray bursts, neutron star characteristics, and (for the first time) verification of theoretical ideas about how the very heavy elements, like gold, are produced. Astronomers have now used a single gravitational wave event (GW170817) to measure the age of the universe. CfA astronomers Peter Blanchard, Tarreneh Eftekhari, Victoria Villar, and Peter Williams were members of a team of 1314 scientists from around the world who contributed to the detection of gravitational waves from a merging pair of binary neutron stars, followed by the detection of gamma-rays, and then the identification of the origin of the cataclysm in a source in the galaxy NGC4993 spotted in images taken with various time delays at wavelengths from the X-ray to the radio. An analysis of the gravitational waves from this event infers their intrinsic strength. The observed strength is less, implying (because the strength diminishes with distance from the source) that the source is about 140 million light-years away. NGC4993, its host galaxy, has an outward velocity due to the expansion of the universe that can be measured from its spectral lines. Knowing how far away it is and how fast the galaxy is moving from us allows scientists to calculate the time since the expansion began – the age of the universe: between about 11.9 and 15.7 billion years given the experimental uncertainties. Read more at: https://phys.org/news/2018-01-gravitational-universe.html#jCp the paper: https://www.nature.com/nature/journal/v551/n7678/full/nature24471.html A gravitational-wave standard siren measurement of the Hubble constant: On 17 August 2017, the Advanced LIGO1 and Virgo2 detectors observed the gravitational-wave event GW170817—a strong signal from the merger of a binary neutron-star system3. Less than two seconds after the merger, a γ-ray burst (GRB 170817A) was detected within a region of the sky consistent with the LIGO–Virgo-derived location of the gravitational-wave source4, 5, 6. This sky region was subsequently observed by optical astronomy facilities7, resulting in the identification8, 9, 10, 11, 12, 13 of an optical transient signal within about ten arcseconds of the galaxy NGC 4993. This detection of GW170817 in both gravitational waves and electromagnetic waves represents the first ‘multi-messenger’ astronomical observation. Such observations enable GW170817 to be used as a ‘standard siren’14, 15, 16, 17, 18 (meaning that the absolute distance to the source can be determined directly from the gravitational-wave measurements) to measure the Hubble constant. This quantity represents the local expansion rate of the Universe, sets the overall scale of the Universe and is of fundamental importance to cosmology. Here we report a measurement of the Hubble constant that combines the distance to the source inferred purely from the gravitational-wave signal with the recession velocity inferred from measurements of the redshift using the electromagnetic data. In contrast to previous measurements, ours does not require the use of a cosmic ‘distance ladder’19: the gravitational-wave analysis can be used to estimate the luminosity distance out to cosmological scales directly, without the use of intermediate astronomical distance measurements. We determine the Hubble constant to be about 70 kilometres per second per megaparsec. This value is consistent with existing measurements20, 21, while being completely independent of them. Additional standard siren measurements from future gravitational-wave sources will enable the Hubble constant to be constrained to high precision.

I havn't read the book "Rare Earth" and took the unique comment to mean "one off" My idea of an earth like planet, is one that will support life as we know it. That does not rule out the possibility of life as we don't know it. And yes most certainly we have no empirical evidence to show that life exists anywhere else but on Earth, but as I have said many times, when one considers the "near infinite" extent and content of just our observable universe, and the stuff of life being everywhere we look, I see it as rather reasonable to conclude that life should arise elsewhere. Many cosmologists and scientists today believe that evidence of the existence of life elsewhere may reveal itself sooner then later. If it did happen that life only existed on this fart arse little blue orb, then I believe it would raise far many more questions. What reasons does anyone have to believe that there cannot be other planets more suitable for humans? We just don't know at this time.

Earth like planets, within habitable/Goldilocks zones, are always the hardest to detect for obvious reasons. Any star will have a potential habitable zone. Our earth is unique??? What prompts you to believe this? Humanity once thought that the Earth was the center of the universe...now we find that we ain't even the center of our galaxy. Our earth unique? Not really likely considering the scale and numerical content of the universe that we know. Yep, fantastical magical like technology, and most certainly at this time far in advance of anything we could even hope to dream on. But if we are able to survive any potential cosmological catastrophe, or our own Earthly follies, then perhaps in 500 years, a 1000 years, or 10,000 years we may have a better idea of how to achieve such fantastic technology.

Are you speaking of Kaku's book Hyperspace? I have read it too, and like you I'm not a scientist either, but I have also read much more then just Kaku's book. String theory and its derivitives, while seemingly being mathematically beautiful, are at this time all still speculative and hypothetical. The simple facts are that despite some impressive technology, like the LHC, as yet, we simply cannot observe at such tiny scales to verify one way or the other. I'm certainly not knocking string theory, or any other potential quantum gravity theory just yet, but until we have the ability and technology, or other evidence to support them, they remain just interesting discussion points.

The theory of the evolution of life is as close to certainty as any one could wish for. While Abiogenesis is the process by which life first arises or appears. While knowledge of Abiogenesis is scant, in realty it is really the only scientific answer open to acceptence, when discussing universal Abiogenesis. Earthly Abiogenesis is of course open to the possibility of Panspermia.