beecee

No. The universe is expanding only over the larger scales. Over small scales such as our solar neighbourhood, our galaxy, our local group of galaxies, and even the cluster we are apart of, are "decoupled" from that expansion rate due to gravity. You are correct though that due to the expansion of space over large scales, galaxies near the observational horizon, will eventually be unable to be seen. And of course every time we look at the stars, we are seeing them as they were.eg; Alpha Centauri system...4.5 years ago, Andromeda galaxy, 2 million years ago.

In that case what I am now posting is also off topic, but it does reflect another side of how we approach mainstream science with thoughts, ideas, conjecture, and hypothesis that most people with any passing interest in astronomy/cosmology probably has every day of the week. I'm nothing more then a retired Maintenance Fitter/machinist/welder that has always been interested in space and cosmology from a very early age. But in my day, my old man got me an apprenticeship and I possibly missed something I dearly love in the astronomy sciences as a career. I did though keep roughly abreast of new findings and such in cosmology and such and started doing some reputable reading from reputable mainstream science books. Hawking's "A Brief History of Time" was probably the first which though read at a middle mature age, sparked my interests again and subsequently I started reading many more reputable books such as Gravity's Fatal Attraction, Black Holes and Time Warps, The First Three Minutes, and some not so reputable books such as The Big Bang Never Happened, and The Bermuda Triangle. This coupled with taking part in science forums such as this, helped me gain what limited knowledge I now have. I also had ideas re Singularities, White Holes, etc and what I believed to be reasonable assumptions and extensions on what mainstream science presented. Having had learnt the basics though re what the scientific method entails, and how science is always progressing and changing as data is forthcoming, I did not attempt to push any of my ideas as "theory" or "gospel" but sat back and listened to those that did appear to be educated and professional in that discipline, and the more I did learn, the more it dawned on me that my ideas were just speculative scenarios without any observational evidence and without any mathematical data to support them. Like I told Bez early on, its admirable to "think for one's self" but just as Imagination goes hand in hand with knowledge, so to does listening go hand in hand with thinking for one's self, and being humble enough to know one's limitations.

Establishing colonies on Mars will be many times more difficult and dangerous then a Moon colony or outpost. Just getting to Mars is many orders of magnitude more difficult then to the Moon. I see establishing a Lunar outpost as far more advisable then a Martian outpost. I often get tired and irritable when those arguments are trotted out. The facts are, in the course of time, we will return to the Moon, we will establish a colony or outpost, we will set foot on Mars, and if we are able to overcome our Earthly follies and squabbles and not destroy ourselves, will venture even further afield. Even simply for the mundane reason of "because its there"

Well put!

Thank you Gentlemen, I'll take action accordingly. No reason Strange, just me.

OK, Just woke up gone to the bathroom for the usual, make myself a cup of coffee, open up the computer to find out that I forgot to log out from the forum last night. This isn't the first time either. Is there any way after say an hour or so of inaction by a member online, that he or she is then automatically logged out? Nothing critical of course can develop from that but it is annoying at least from my perspective. Just a suggestion.

I'm beginning to think that someone is actually having a lend of us at this stage.....IQ of 160 etc etc

My apologies, I thought I was being nice! Let me correct you again, as nicely as possible. We often have the claims from unqualified people with what they see as bright ideas, that mainstream science is incalcitrant and as you say, dogmatic. That is obviously wrong and is illustrated every day to be wrong. I thought I did mention it in your other thread that science is a discipline in continued progress....There are young physicists and cosmologists trying to find limits, or falsify incumbent theories every day...including Einstein's GR theory. These are of course qualified and professionals doing science. You see that is what science is all about. Making further observations...conducting more experiments...comparing results with incumbent data and theories. Sometimes they succeed. Sometimes they find something better, just as Einstein did before GR [and SR] became accepted. But they need empirical observational evidence...Not just some raw idea or gut feeling. As was mentioned to you more then once, the first step is to know thoroughly what you are trying to falsify or invalidate. Otherwise your hypotheticals are useless, as hard as that is to accept. Do you have access to aLIGO? Or the LHC? or a telescope? or the Planck Satellite or any other pieces of the state of the art equipement that scientists do?

It will be interesting to hear what he has to say. I'm sure he'll be kind to you. https://en.wikipedia.org/wiki/Electromagnetism https://www.school-for-champions.com/science/electromagnetism.htm#.XNoRrNQzY2w You understand that light is just a part of the EMS [electromagnetic spectrum]

I have always loved the old 40's/50's musicals and one of the greatest proponents of these musicals was of course the now late Doris Day...Rip Doris!

Sure, agreed, I was though referring to the fact of the Sun's Corona being hotter then the photosphere by many orders of magnitude, and the general thought that this was due to magnetic fields emanating from deep within the Sun. And of course that the mechanics of the Sun/stars are fusion based. Perhaps I should have made that more clear. Again though, I still fail to understand his [Bez] apparent infatuation with friction?

All motions of bodies in the universe can be put down to conservation laws and gravity. You also seem overly concerned and confused re friction. Nuclear fusion and of course the corona and associated heat probably due to magnetic fields from deep within the Sun. Again, you seem preoccupied with friction.

Let's lift the tone of this place for a while! May I present an Angel! a Greek Angel! singing an old number from a movie classic, Casablanca:

If you are referring to the scientific theory that the Earth's molten core is caused by radioactive decay and along with the heat left over from formation, as being only hypothetical, then you are wrong. It is the current best evidenced theory of the Earth's molten core according to current knowledge and evidence. https://www.livescience.com/15084-radioactive-decay-increases-earths-heat.html Also you do realize that a scientific theory is as good as it gets, don't you? Further observational evidence and data forthcoming can always possibly moderate or even invalidate a scientific theory, and obviously also, further enhance such theory and make them even more certain. eg: the discovery of predicted gravitational waves further enhancing GR. It's always admirable to see someone thinking for themselves, and on that score you get points. But coupled with that thinking for one's self, must be first and foremost, total knowledge of what is entailed and evidenced in the accepted incumbent version of the relevant science discipline being researched... There is absolutely nothing to support your hypothetical conjecture...no observational evidence, no maths, no predictive powers, nothing. A hypothetical is absolutely useless if not supported by evidence. I could just as well invoke a magical spaghetti monster as equal to what you are proposing.

If that is the prime reason as far as NASA and the USA is concerned, is there really anything wrong with that? How about simply because its there? for the Adventure, exploration, etc, and obviously any exploratory venture should lead to knowledge. Costs of course are still prohibitive but then again, why not a concerted effort for an International venture?

All real problems certainly. And all will certainly be considered if this takes place either sooner then later. It will happen in the course of time but, you agree? And wouldn't an International effort be beneficial?

Here is another article with relation to heavier elements..... https://phys.org/news/2019-05-collapsar-accretion-disks-source-heaviest.html Researchers suggest collapsar accretion disks might be source of heaviest elements: A trio of researchers at Columbia University is suggesting that collapsar accretion disks might be the major source of the heaviest elements. In their paper published in the journal Nature, Daniel Siegel, Jennifer Barnes and Brian Metzger describe their study of the accretion disks that form as neutron stars collapse into black holes, and what they found. extract: Prior research has suggested that the heaviest elements were created by what is known as the "r-process," in which a chain reaction results in atomic nuclei absorbing neutrons. Astrophysicists had theorized that two neutron stars colliding would likely give way to the conditions necessary for the r-process to occur, creating some of the heaviest elements. Two years ago, the team credited with observing the first gravity waves reported the effects of two neutron stars colliding. Subsequent study of the event showed that it was likely that the r-process had occurred, giving strong credence to the theory. But there was still one problem. The collision of neutron stars is a rare event—too rare to account for the amount of the heaviest elements that exist today. That led the researchers to consider other neutron star activities—such as their gravitational collapse. more at link...... and the paper: https://www.nature.com/articles/s41586-019-1136-0 <<<<<<<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> and an earlier article from 2018 on the same process possibilities..... https://physicstoday.scitation.org/doi/10.1063/PT.3.3815 extract: "The remainder of the chemical elements, except for a tiny amount of lithium, were forged in stellar interiors, supernova explosions, and neutron-star mergers. Elements up to and including iron are made in the hot cores of short-lived massive stars. There, nuclear fusion creates ever-heavier elements as it powers the star and causes it to shine. Elements heavier than iron—the majority of the periodic table—are primarily made in environments with free-neutron densities in excess of a million particles per cubic centimeter. The free neutrons, if captured onto a seed nucleus, result in a heavier, radioactive nucleus that subsequently decays into a stable heavy species. The so-called slow neutron-capture process, or s-process, mostly occurs during the late stages in the evolution of stars of 1–10 solar masses (M⊙). But the s-process accounts for the formation of only about half of the isotopes beyond iron. Creating the other half requires a rapid capture sequence, the r-process, and a density of greater than 1020 neutrons/cm3 that can bombard seed nuclei. The requisite neutron fluxes can be provided by supernova explosions (see the article by John Cowan and Friedrich-Karl Thielemann, Physics Today, October 2004, page 47) or by the mergers of binary neutron-star systems". and relevant to Swansont's comment...... "Nuclear physicists are still working to model the r-process, and astrophysicists need to estimate the frequency of neutron-star mergers to assess whether r-process heavy-element production solely or at least significantly takes place in the merger environment." the article then goes on to say..... "To test r-process models, nuclear physicists will need to obtain measurements or solid predictions of the fundamental properties of heavy, unstable nuclei that lie far from the valley of stability occupied by familiar long-lived isotopes—they’ll need to know, for example, about masses, nuclear interaction cross sections, and decay rates. Procuring such data is a primary science driver for several international accelerator facilities. The US representative, the Facility for Rare Isotope Beams, is currently under construction at the campus of Michigan State University and is expected to be completed in 2022". :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: Excellent article and far more informative then the latter article in the OP!! Associated references from the above article.... https://science.sciencemag.org/content/358/6370/1570 Early spectra of the gravitational wave source GW170817: Evolution of a neutron star merger https://science.sciencemag.org/content/358/6370/1574 Early spectra of the gravitational wave source GW170817: Evolution of a neutron star merger https://iopscience.iop.org/article/10.1088/0004-637X/814/1/58/meta MERGER RATES OF DOUBLE NEUTRON STARS AND STELLAR ORIGIN BLACK HOLES: THE IMPACT OF INITIAL CONDITIONS ON BINARY EVOLUTION PREDICTIONS :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

Just to add though, obviously you seem to be comparing a basically science news site as is "physorg," with a science paper publishing company publishing peer reviewed articles as is "nature". I mostly include both as both give relevant outlines of the relevant news item I'm posting. Please take the time to read the many other articles and papers I post here in an effort to promote scientific discussion.

Here is another article on this concept of Planetary Migration... https://phys.org/news/2019-05-gravitational-protoplanetary-disks-super-earths-stars.html Gravitational forces in protoplanetary disks may push super-Earths close to their stars: The galaxy is littered with planetary systems vastly different from ours. In the solar system, the planet closest to the Sun—Mercury, with an orbit of 88 days—is also the smallest. But NASA's Kepler spacecraft has discovered thousands of systems full of very large planets—called super-Earths—in very small orbits that zip around their host star several times every 10 days. Now, researchers may have a better understanding how such planets formed. A team of Penn State-led astronomers found that as planets form out of the chaotic churn of gravitational, hydrodynamic—or, drag—and magnetic forces and collisions within the dusty, gaseous protoplanetary disk that surrounds a star as a planetary system starts to form, the orbits of these planets eventually get in synch, causing them to slide—follow the leader-style—toward the star. The team's computer simulations result in planetary systems with properties that match up with those of actual planetary systems observed by the Kepler space telescope of solar systems. Both simulations and observations show large, rocky super-Earths orbiting very close to their host stars, according to Daniel Carrera, assistant research professor of astronomy at Penn State's Eberly College of Science. more at link...... the paper: https://academic.oup.com/mnras/article-abstract/486/3/3874/5432363?redirectedFrom=fulltext Formation of short-period planets by disc migration: ABSTRACT: Protoplanetary discs are thought to be truncated at orbital periods of around 10 d. Therefore, the origin of rocky short-period planets with P < 10 d is a puzzle. We propose that many of these planets may form through the Type-I migration of planets locked into a chain of mutual mean motion resonances. We ran N-body simulations of planetary embryos embedded in a protoplanetary disc. The embryos experienced gravitational scatterings, collisions, disc torques, and dampening of orbital eccentricity and inclination. We then modelled Kepler observations of these planets using a forward model of both the transit probability and the detection efficiency of the Kepler pipeline. We found that planets become locked into long chains of mean motion resonances that migrate in unison. When the chain reaches the edge of the disc, the inner planets are pushed past the edge due to the disc torques acting on the planets farther out in the chain. Our simulated systems successfully reproduce the observed period distribution of short-period Kepler planets between 1 and 2 R⊕. However, we obtain fewer closely packed short-period planets than in the Kepler sample. Our results provide valuable insight into the planet formation process, and suggests that resonance locks, migration, and dynamical instabilities play important roles in the formation and evolution of close-in small exoplanets.

https://phys.org/news/2019-05-lunar-tunnel-moon-colonies.html Lunar tunnel engineers excited by boring Moon colonies: As space agencies prepare to return humans to the Moon, top engineers are racing to design a tunnel boring machine capable of digging underground colonies for the first lunar inhabitants. "Space is becoming a passion for a lot of people again. There are discussions about going back to the moon, this time to stay," US-Iranian expert Jamal Rostami told AFP at this year's World Tunnel Congress in Naples. The administration of US President Donald Trump wants NASA to put humans back on the Moon by 2024, and the agency is also drawing up plans for a "Gateway" station to serve as a platform for astronauts travelling to and from the lunar surface. Billionaires Elon Musk and Jeff Bezos are among those feverishly competing for military, civil or commercial launches, with Musk's SpaceX leading the race on building rockets ready to fly in time. more at link..... ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: Donald Trump or no Donald Trump, Government or private, the only question as far as I can see is whether this happens sooner or later. Costs will always be a question, [along with the many other questions put in the article] which is why I have always thought an International effort for returning to the Moon and eventually putting foot prints on Mars, in an as safe as is humanly possible way need be undertaken. The success of the ISS shows this to be a reasonable and possible scenario. What is the general consensus of opinion here on this question?

No problem et pet, and thanks again for posting the paper. On occasions yes, which is why I normally include the paper. Perhaps not with nature, but "most" certainly do...seems to be a natural process with journalism. I would also add and I am sure you will agree, that the expertise on this forum in general, are always quick to highlight or dispute any wrong or false conclusion from any article and the journalism portrayed within.

OK, good question...If it did I would say it would be classified as a sub Brown Dwarf? Just a guess though on my part, someone more attuned to these classifications from rocky planet to gaseous planet, to brown dwarf to star may shed more light. Actually your previous post re deuterium fusion in Jupiter is something I have not heard of.

I found this which seems to support what I said.....https://en.wikipedia.org/wiki/Brown_dwarf extract: "Below this range are the sub-brown dwarfs (sometimes referred to as rogue planets), and above it are the lightest red dwarfs (M9 V). Brown dwarfs may be fully convective, with no layers or chemical differentiation by depth.[3] Unlike the stars in the main sequence, brown dwarfs are not massive enough to sustain nuclear fusion of ordinary hydrogen (1H) to helium in their cores. They are, however, thought to fuse deuterium (2H) and to fuse lithium (7Li) if their mass is above a debated[4] threshold of 13 MJand 65 MJ, respectively.[2] It is also debated whether brown dwarfs would be better defined by their formation processes rather than by their supposed nuclear fusion reactions."

Depends on mass afaik....with Jupiter it is thought that at the core, metallic hydrogen may exist, or at least take on similar metallic properties. The next step up, again depending on mass, is the Brown Dwarf stage where possible limited core fusion may take place....

Thanks.