beecee

As the title in the thread says, Incredible news...at least that is the way I see it. First attempt and success! The other point seems to be that China is progressing at a reasonable rate, without comprimising safety and success. Also the landing process and mechanisim seems less complicated then Curiosity...no sky crane. From the link....."A 200 square meter (2,150 square foot) parachute was deployed and later jettisoned, and then a retro-rocket was fired to slow the speed of the craft to almost zero, Xinhua said. The craft hovered about 100 meters (330 feet) above the surface to identify obstacles before touching down on four buffer legs". Bring rocks back from the Moon, the beginnings of a space station, and now landing a craft on Mars.... they are doing pretty well I suggest.

defining Space by itself is simply that which exists between you and me, between the planets and the Sun, between the Sun and Alpha Centauri. But space doesn't exist by itself. It exists in unison with time. Bother evolved [as we know them] from t+10-45 second....one cannot exist without the other...they are interchangeable in effect. On that point alone your hypothetical collapses. That's why we have spcetime as the multi dimensional framework in which we locate all events, and as we know [and which validates the point I'm making] intervals of space and time when considered apart, are variable depending depending on the observer in different frames of references. Nothing is leaving the universe. The universe is all there is, is all the evidence shows. The universe/space/time is what we exist in. DM is simply a part of that universe/space/time. Yet the evidence shows DM is spread throughout the universe. And I'm not sure if the following supports your claim...https://en.wikipedia.org/wiki/Bullet_Cluster

https://phys.org/news/2021-05-nihao-mars-china-zhurong-rover.html China lands on Mars in major advance for its space ambitions: In this photo released by Xinhua News Agency, members at the Beijing Aerospace Control Center celebrate after China's Tianwen-1 probe successfully landed on Mars, at the center in Beijing, Saturday, May 15, 2021. China landed a spacecraft on Mars for the first time on Saturday, a technically challenging feat more difficult than a moon landing, in the latest advance for its ambitious goals in space. (Jin Liwang/Xinhua via China landed a spacecraft on Mars for the first time on Saturday, a technically challenging feat more difficult than a moon landing, in the latest step forward for its ambitious goals in space. Plans call for a rover to stay in the lander for a few days of diagnostic tests before rolling down a ramp to explore an area of Mars known as Utopia Planitia. It will join an American rover that arrived at the red planet in February. China's first Mars landing follows its launch last month of the main section of what will be a permanent space station and a mission that brought back rocks from the moon late last year. more at link.....................

https://www.nasa.gov/feature/jpl/nasa-s-juno-mission-expands-into-the-future This view from the JunoCam imager on NASA’s Juno spacecraft shows two storms merging. The two white ovals seen within the orange-colored band left of center are anticyclonic storms – that is, storms that rotate counterclockwise. The image was taken on Dec. 26, 2019. Credits: NASA/JPL-Caltech/SwRI/MSSS Image processing by Tanya Oleksuik, © CC BY The spacecraft, which has been gathering data on the gas giant since July 2016, will become an explorer of the full Jovian system – Jupiter and its rings and moons. NASA has authorized a mission extension for its Juno spacecraft exploring Jupiter. The agency’s most distant planetary orbiter will now continue its investigation of the solar system’s largest planet through September 2025, or until the spacecraft’s end of life. This expansion tasks Juno with becoming an explorer of the full Jovian system – Jupiter and its rings and moons – with multiple rendezvous planned for three of Jupiter’s most intriguing Galilean moons: Ganymede, Europa, and Io. more at link.......

The part we can perceive? That is called the observable universe, which is entailed by "c " and the time that the EMR has had to reach us within the known age of the universe and the expansion rate. That's nice....as a lay person myself, I re-enforce my knowledge by reading reputable books, then through forums such as this, if there is something I don't understand, I ask questions. The general picture of the evolution of space/time/universe is a model that to me anyway, makes a lot of sense. Prior to t+10-45 seconds, where the BB and laws of physics does fail us, I also have my own hand waving ideas...I speculate that the BB is actualy the arse end of a BH, which we call a White Hole. but you also said, Science creates models that match observational data and tells us what is happening. The why it is happening is another aspect. There is a great little video [only 7 minutes long] that explains what I mean by Richard Feynman. I have linked to it many times, but I also believe it is informative and tells us the role of science....https://www.youtube.com/watch?v=Q1lL-hXO27Q The other point I would make is like you, I am relatively mathematically ignorant, and maths being the language of physics, leaves people like you and me, behind the eight ball somewhat. I hope you take the 7.5 minutes to watch the video...quite impressive by an impressive scientist. In conclusion I would just remind you that while GR is our most accurate model of gravity, it does not [as some people often say] determine that Newtonian gravity is wrong. Newtonian gravity is simply a less accurate model, but accurate enough for us to use every day on Earth, and accurate enough to be the model used in most space endeavours. We could if we wanted to use the more accurate GR, but it does entail much more mathematical equations, to give us the same answer, [but with more accurate results] and is not really needed. Join the club!! I'm an old bastard, but still hope I'm around to eventually see boots on Mars....at least!!😉

https://phys.org/news/2021-05-physicists-neutron-stars-bigger-previously.html Physicists predict neutron stars may be bigger than previously imagined: When a massive star dies, first there is a supernova explosion. Then, what's left over becomes either a black hole or a neutron star. That neutron star is the densest celestial body that astronomers can observe, with a mass about 1.4 times the size of the sun. However, there is still little known about these impressive objects. Now, a Florida State University researcher has published a piece in Physical Review Letters arguing that new measurements related to the neutron skin of a lead nucleus may require scientists to rethink theories regarding the overall size of neutron stars. In short, neutron stars may be larger than scientists previously predicted. more at link............... the paper: https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.126.172503 Implications of PREX-2 on the Equation of State of Neutron-Rich Matter: ABSTRACT: Laboratory experiments sensitive to the equation of state of neutron rich matter in the vicinity of nuclear saturation density provide the first rung in a “density ladder” that connects terrestrial experiments to astronomical observations. In this context, the neutron skin thickness of 208Pb (R208skin) provides a stringent laboratory constraint on the density dependence of the symmetry energy. In turn, an improved value of R208skin has been reported recently by the PREX collaboration. Exploiting the strong correlation between R208skin and the slope of the symmetry energy L within a specific class of relativistic energy density functionals, we report a value of L=(106±37)  MeV—which systematically overestimates current limits based on both theoretical approaches and experimental measurements. The impact of such a stiff symmetry energy on some critical neutron-star observables is also examined.

https://phys.org/news/2021-05-extraterrestrial-radioactive-isotope-seabed-implications.html MAY 14, 2021 Extraterrestrial radioactive isotope found in seabed has implications for Earth's origins:\ The first-ever discovery of an extraterrestrial radioactive isotope on Earth has scientists rethinking the origins of the elements on our planet. The tiny traces of plutonium-244 were found in ocean crust alongside radioactive iron-60. The two isotopes are evidence of violent cosmic events in the vicinity of Earth millions of years ago. Star explosions, or supernovae create many of the heavy elements in the periodic table, including those vital for human life, such as iron, potassium and iodine. To form even heavier elements, such as gold, uranium and plutonium it was thought that a more violent event may be needed, such as two neutron stars merging. more at link................ the paper: https://science.sciencemag.org/content/372/6543/742 Abstract: Half of the chemical elements heavier than iron are produced by the rapid neutron capture process (r-process). The sites and yields of this process are disputed, with candidates including some types of supernovae (SNe) and mergers of neutron stars. We search for two isotopic signatures in a sample of Pacific Ocean crust—iron-60 (60Fe) (half-life, 2.6 million years), which is predominantly produced in massive stars and ejected in supernova explosions, and plutonium-244 (244Pu) (half-life, 80.6 million years), which is produced solely in r-process events. We detect two distinct influxes of 60Fe to Earth in the last 10 million years and accompanying lower quantities of 244Pu. The 244Pu/60Fe influx ratios are similar for both events. The 244Pu influx is lower than expected if SNe dominate r-process nucleosynthesis, which implies some contribution from other sources.

Off course time is not attracted to gravity. Time as a dimension, along with space and the three spatial dimensions, cause the effect we know as gravity, by geometrical curving/warping in the presence of mass/energy. Time [as a separate entity]would still exist and pass in a flat spacetime without mass/energy. And of course the universe is flat over large dimensions and within small error bars. What does it mean to say the universe is flat? Basically that two beams of light emmited parallel to each other, remain parallel. The point is whether the universe is flat, open, or closed, time as a separate entitiy will always pass. Finally in line with our best overwhelmingly supported model, the BB, time itself, as a separate entitiy, came into existence when space started to evolve. Not sure if all that answers your question, and while time is real, despite not being a physical entity, it does appear to be fundamental as does the spatial dimensions of space.

My position is that held and suported by observational and experimental data. Not at all. The vast majority of professional cosmologists hold that view, and it is supported by the evidence. While Tesla made some notable discoveries, he was also some what eccentric.

I have read his excellent book, "Black Holes and Time Warps" one of the things that got me interested in this stuff. Every Mother believes her new born child to be the most beautiful.

Question: Why don't blind people bungee jump? Answer: Because it scares the fuck out of the dog.

Space is what we see as volume and what keeps things apart. Time is what stops everything from happening at the same instant and can be defined as the rate of change, or what clocks measure. Both depend on one another and either would not exist without the other. Space and time are interchangeable...hence the notion of spacetime. So no, its not a mistake. The fact that two people in two different FoR's, will not agree on a particular distance or on the rate of change [time] supports the model of spacetime and the fact that Intervals of space and time when considered separately, are not the same for all observers. And as Minkowski [Einstein's teacher] said........ https://en.wikipedia.org/wiki/Minkowski_space "The views of space and time which I wish to lay before you have sprung from the soil of experimental physics, and therein lies their strength. They are radical. Henceforth space by itself, and time by itself, are doomed to fade away into mere shadows, and only a kind of union of the two will preserve an independent reality".  Hermann Minkowski :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: Obviously, any mistake is yours.

😁 Well said! On the OP though, time travel is allowed for by GR and the laws of physics. The following link explains.......https://plus.maths.org/content/time-travel-allowed

From the paper or article of course. OK, I see what you mean...it is from the physorg article and while it didn't really cause me any great concern, I would say it's just poor journalism by the physorg journalist, which is why with any interesting article I reproduce, I will also supply the scientific paper below that article. Otherwise I find yours and studiot's comments informative and adding more knowledge to my own scant geological knowledge. Thanks.

Obviously the highlighted bit by me is wrong. 14 parsecs = 45.6 light years and 14x 10 to the 9th power = 4,660,000,000 sorry for the stuffup. Like I said, I'll leave the maths to swansont. Underlying correction also to my first post....scrub the "14 parsecs or"

I'm puzzled on a few counts by what I see as errors....first from your link "and every galaxy harbors a supermassive black hole at its center"...I'm not sure if that statement is really concrete as your article says... https://www.forbes.com/sites/brucedorminey/2020/12/20/galaxy-may-be-missing-its-supermassive-black-hole-says-nasa/?sh=7d361d59735b perhaps its hard to detect because its dormant? Yes certainly most spiral galaxies as well as others do have SMBH's at their core........ The other point gets to the title of your thread, re the mass/radius of the observable universe and BH's. Your link gives the radius of the observable universe as 14 billion light years. That refers to how long ago the BB occured...13.83 billion years ago. Due to spacetime expansion the radius of the observable universe is about 47 billion light years. Plus the observable univere's parameters are determined by how much the universe has expanded, the rate/decelleration/acceleration and the speed of light. In other words, anything beyond how far any light could travel within the age of the universe [13.83 billion years] is beyond the observable universe. This is about 14 parsecs or 47 billion light years radius.

Thank you for a down to Earth explantion.

Turkish? 😉 from the article..... illustrative Elements of a newly discovered process in plate tectonics include a mass (rock slab weight), a pulley (trench), a dashpot (microcontinent), and a string (oceanic plate) that connects these elements to each other. In the initial state, the microcontinent drifts towards the subduction zone (Figure a). The microcontinent then extends during its journey to the subduction trench owing to the tensional force applied by the pull of the rock slab pull across the subduction zone (Figure b). Finally, the microcontinent accretes to the overriding plate and resists subduction due to its low density, causing the down-going slab to break off (Figure c). Credit: Erkan Gün/University of Toronto There is also an illustrative video

https://phys.org/news/2021-05-discovery-geologic-plate-tectonic.html Discovery of new geologic process calls for changes to plate tectonic cycle: Geoscientists at the University of Toronto (U of T) and Istanbul Technical University have discovered a new process in plate tectonics which shows that tremendous damage occurs to areas of Earth's crust long before it should be geologically altered by known plate-boundary processes, highlighting the need to amend current understandings of the planet's tectonic cycle. Plate tectonics, an accepted theory for over 60 years that explains the geologic processes occurring below the surface of Earth, holds that its outer shell is fragmented into continent-sized blocks of solid rock, called "plates," that slide over Earth's mantle, the rocky inner layer above the planet's core. As the plates drift around and collide with each other over million-years-long periods, they produce everything from volcanoes and earthquakes to mountain ranges and deep ocean trenches, at the boundaries where the plates collide. Now, using supercomputer modelling, the researchers show that the plates on which Earth's oceans sit are being torn apart by massive tectonic forces even as they drift about the globe. The findings are reported in a study published this week in Nature Geoscience. more at link................ the paper: https://www.nature.com/articles/s41561-021-00746-9 Pre-collisional extension of microcontinental terranes by a subduction pulley: Abstract: Terrane accretion is a ubiquitous process of plate tectonics that delivers fragments of subduction-resistant lithosphere into a subduction zone, resulting in events such as ocean plateau docking or continental assembly and orogenesis. The post-collisional extension of continental terranes is a well-documented tectonic process linked with gravitational collapse and/or trench retreat. Here we propose that microcontinental terranes can also undergo a substantial extension before their collision with the upper plate, owing to pull from the trenchward part of the subducting plate. Forward geodynamic numerical experiments demonstrate that this pre-collisional extension can occur over a protracted phase on microcontinents that are drifting towards a subduction zone, which distinguishes the deformation from post-collisional extension on the overriding plate, as is traditionally postulated. The results show that the magnitude of pre-collisional extension is inversely correlated with the size of the microcontinental terrane and imposed convergence velocity. We find that locations along the Tethyan belts, namely, the Sesia zone and Eastern Anatolia, are evidence for this style of pre-collisional extension, as this mechanism reconciles with geothermobarometric data and kinematic analyses. The operation of this subduction pulley reveals that drifting lithospheric plates may undergo substantial tectonic events before the arrival and involvement with regular plate boundary processes.

The following is an article and paper I came across. Can a relativist/physicist please explain in simpler detail, if possible? particulalry the following..."There are four distinct rotational relativistic transformations in the literature: the Langevin metric; Post transformation; Franklin transformation; and the absolute Lorentz transformation (ALT) in its rotational form." and how is validates or otherwise relativity. https://phys.org/news/2021-05-optical-reveal-basic-spacetime-rotating.html Researchers use optical data to reveal the basic structure of spacetime in rotating frames: One of the most basic structural aspects of relativistic spacetime is the description of how time and distances are altered by motion. The theory of special relativity describes a spacetime framework for linear constant motion in which time dilates and lengths contract in response to motion. This framework is described by the Lorentz transformation, which encompasses mathematical formulas that describe how time and distance are altered between moving reference frames. The Lorentz transformation also describes how a stationary observer views time in the moving frame to be offset with distance. The offsetting of time with distance between reference frames generates differential simultaneity, in which events that are simultaneous for one observer will not be simultaneous for a second observer moving relative to the first observer. more at link.... the paper: https://www.worldscientific.com/doi/abs/10.1142/S0217732321501133 Abstract Rotational transformations describe relativistic effects in rotating frames. There are four major kinematic rotational transformations: the Langevin metric; Post transformation; Franklin transformation; and the rotational form of the absolute Lorentz transformation. The four transformations exhibit different combinations of relativistic effects and simultaneity frameworks, and generate different predictions for relativistic phenomena. Here, the predictions of the four rotational transformations are compared with recent optical data that has sufficient resolution to distinguish the transformations. We show that the rotational absolute Lorentz transformation matches diverse relativistic optical and non-optical rotational data. These include experimental observations of length contraction, directional time dilation, anisotropic one-way speed of light, isotropic two-way speed of light, and the conventional Sagnac effect. In contrast, the other three transformations do not match the full range of rotating-frame relativistic observations.

https://phys.org/news/2021-05-space-telescope-golden-mirror-wings.html Space telescope's golden mirror wings open one last time on Earth: The process of deploying, moving, expanding and unfurling all of Webb's many movable pieces after they have been exposed to a simulated launch is the best way to ensure they will perform as intended once in space. Credit: NASA/Chris Gunn For the last time while it is on Earth, the world's largest and most powerful space science telescope opened its iconic primary mirror. This event marked a key milestone in preparing the observatory for launch later this year. As part of the NASA's James Webb Space Telescope's final tests, the 6.5-meter (21-foot, 4-inch) mirror was commanded to fully expand and lock itself into place, just like it would in space. The conclusion of this test represents the team's final checkpoint in a long series of tests designed to ensure Webb's 18 hexagonal mirrors are prepared for a long journey in space, and a life of profound discovery. After this, all of Webb's many movable parts will have confirmed in testing that they can perform their intended operations after being exposed to the expected launch environment. more at link......

Mars by 2024? I voted no. That doesn't mean that I believe all efforts should stop. I hope to Christ that they do succeed and sincerely wish them the best of luck, in that they are able to put boots on Mars and return them safely, with minimal risk.

I see even the thought of that as stagnation and a total lack of foresight. Actually the opposite. The scientists at NASA and the ESA and other space companies, know too well the dangers of space travel. As a great President of the USA once said, "we don't do these things because they are easy; we do them because they are hard" Space flight including tourism will in time get cheaper as technologies and safety improve. No we can't afford to be complacent, and I don't believe we generally are. Space travel and tourism, will become the norm in the course of time and as safety and technological concerns are overcome. The Apollo adventures became the norm and people became rather blaise about these dangerous adventures after Apollo 12: It took a near disaster with Apollo 13 to establish interest again. I did mention it somewhere in the other thread, but its worth contemplating that everyday now for more then 20 years the ISS has had permenant occupancy. What is the daily risk of living in LEO on the ISS? How many space walks have been undertaken in those 20 years? Of course that is an international effort, and such an effort I believe should also occur in putting boots on Mars.

We will put boots on the Moon again, and establish a colony. We will put boots on Mars. We will accomplish even further exploration and more ventures such as mining....all in good time, when all can be done in relative safety. I'm not concerned with anything else.