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Showing content with the highest reputation on 12/31/17 in all areas

  1. 2 points
    You have to be careful here (and in Science generally) since this has more than one meaning. For any observer time passes normally for herself. She just witnesses it passing differently for others who are travelling at (any) speed relative to her. If they are travelling at the same speed together, however great, no effect will be witnessed. The relative speed is zero. The any effect observed will depend on the relative speed and is so small at to be unobservable at low relative speeds. That is why we say there is an effect at high relative speed. Does this help?
  2. 1 point
    Excuse my ignorance first of all. I'm just a guy who never really paid attention in any science class, but now, a bit later in life, I've become very interested. So, (and I may even be starting from a poor understanding) but from what I get, speed, especially light speed, if you're travelling at that speed, has an impact upon your experience of time. Before I go any further, just want to be sure I have that right!
  3. 1 point
    Space between non gravitationaly bound objects such as galaxies increases with time. I have read about the consequences of this phenomenon but not so much about the phenomenon itself. It permits objects to recede from one another at speeds higher than c,I think. Is this speed as seen from a third frame of reference or also from that of one of the objects in question? If the latter is true does that imply that these objects are (never were) not connected in the causative sense? Also ,is Inflation similar to Expansion (differing in degree and circumstance as it were) or are they completely different animals?
  4. 1 point
    What I found hard to accept was that both parties saw the others' clocks (and general movements) as slower than each others' . Also bizarre was the finding that when the mutually moving parties were reunited the time difference accumulated did not disappear to zero. So no "optical illusion" ,but a stark reality born out by experimental observation.
  5. 1 point
    I didn't realize GR could\did model the expansion of the Universe. Are we getting into "Einstein's greatest mistake" territory?
  6. 1 point
    Constant Space December 30, 2017 "Dark matter" and/or "dark energy", seems that is a next in thinking about the whole "universe". Many very intelligent people who study such things are spending a lot of effort, time, and human energy in trying to find out what is this invisible matter, or force, particle, energy, etc. And, if this invisible thing is discovered, then how does it fit in with the BB theory and other ideas as to how the whole universe and all of its "matter" came into being? I'm not a physicist, but I love to read about cosmology, its physics, and ideas about where everything may come from. There are some who think that this dark matter "started" perhaps 10 billion years. IOW, this dark matter was not in existence at the BB's beginning, but that it developed later. Along with this idea comes the idea that after the BB and its explosion of all matter, that matter was all plasma. And, as that plasma was moving outward from the BB center, some areas clumped together creating denser masses in various regions of space. Those areas then condensed and once again became super-heated under their increasing gravity, and then they exploded giving the various regions in space where galaxies developed. Thus, galaxies are not spaced out equally, but in randomly spaced regions in space. Interesting, as many ideas about the universe and its potential origins are. Of course there is still a good bit of critical thinking about whether the BB was real or not, as there are other competing theories such as the constant universe where the universe has always been here and there isn't an actual "age" as the BB theory suggests at roughly 13-14 billion years old. https://phys.org/news/2015-02-big-quantum-equation-universe.html As I've been pondering the idea of dark matter and dark energy like many who know much more than I about the universe, I too was enthralled with the idea that the universe that we've been studying is made up of a majority of material that we can't even see or, as of yet, properly detect. Some physicists have calculated that something like 85% of our "known" universe is made up of material that we can't see or detect. Astounding in concept. I'm thinking, what if "space" is the constant? What if all of the space in the universe has always been here? And, what that space is made of is not affected by gravity like even light is? Perhaps, the visible material that may account for the 15% of what's in space is material that does come from singularities? Thus, space and what it is made of does not condense back down to another future singularity, only to be released again by another Big Bang, but rather, space exists infinitely. And the matter that we've been dealing with since we humans came to wonder, study, and research that matter is the non-constant that affected both by its own physical nature and by the constant space within which it resides. Space, then, is more like a catalyst giving the known material its physical properties, but overall space itself is not changed from its original state. How would that idea affect the mathematics of cosmological mathematicians? I can't do that math. It baffles me. Another thought is that, since we have no idea how expansive the whole universe is, then why do we even assume that we can calculate it? Most agree that space is infinite. Ok, I agree with that. So then, why accept that everything in the universe, including space itself, was contained in the singularity that became the Big Bang? What did the big BANG explode into? If space were not ever present and constant, then what was the void that the Big Bang material exploded in to? If the Big Bang singularity was real, then perhaps it exploded into what we call "space", which contains that 85% of material that calculations suggest must exist in order for the observable galaxies, and what they contain, to have the motion they do have. Also, why must we limit the universe to a single singularity in an infinite space? Perhaps it's very possible that Big Bang like singularities are quite common in the vast infinite universe, and we are only attempting to observe and understand that infinity from our finite position, to us, in an infinite space. Maybe, the force that is pulling our known universe apart is the gravity of all the other matter that spewed out of the other infinite singularities in space. Researchers have physical evidence suggesting that every galaxy has a black hole at its center. These black holes absorb all other matter around them, and as they absorb more they grow larger and have even more gravitational pull to pull in even more. At some point each galaxy's black hole will absorb all of that galaxy's material. However, it appears that black holes do not absorb the space that they are in. From what I understand it has not been observed that space itself is also being absorbed by those black holes, which gives me reason to speculate that space is a constant, and has existed always. And if singularities like the one that created the Big Bang are real, then space does not result from what comes out of that singularity, rather, that material is ejected or released into space. It is also suggested that 2 black holes will merge into a singular larger black hole. The idea that black holes merge to create a larger and larger singularity lends credence to the idea that eventually all of the physical material in every galaxy will be absorbed by each galaxies black hole. And then, those black holes will merge into larger black holes. At some point perhaps there is a limit to how much material can be absorbed until that singularity spews out all of the matter it sucked in. The big question about that is, since we believe that nothing can escape the massive gravity of a black hole, not even light, then what causes that gravity to either reverse or release all the material, or, that gravity simply stops and all that material is released? The thing that exploded to release all that plasma, the Big Bang, was also a singularity. Thus, for some reason something happened that either shut off the gravity or reversed it. Why or what caused that? And, does a constant space have anything to do with that singularities gravity change?
  7. 1 point
    Are you sure? Everything I have read suggests that dark matter has been around as long as matter. One of the lines of evidence for dark matter is the cosmic microwave background (CMB) and that is a lot more than 10 billion years old. The Big Bang model is not an explosion, and certainly not an explosion of matter from some central point. Well, it has. And it is space that has expanded (not matter exploding into space). Space is not made of anything. It is just the distance between things. Which is affected the presence of mass - the effects of this include the thing we call gravity. I don't know if that is true. Everyone agrees we can't know. I don't know what proportion think it is infinite. People pop up on science forums insisting it is impossible for it to be infinite and impossible for it to be finite with about equal frequency. I have never seen a survey of physicists, though. It wasn't an explosion into anything. The universe was once entirely full of hot, dense matter (plasma). The universe expanded and, as a result, the matter cooled and gravity caused the gas to clump into stars and galaxies. There is no "outside". Note that a singularity means that the theory no longer applies at that point - a bit like dividing by zero. There are many variations of the basic Big Bang model. Some of these suggest multiple Big Bang "events" (inflation and expansion) producing multiple universes. These ideas are not really testable but are a natural consequence of the mathematics. For example: https://en.wikipedia.org/wiki/Eternal_inflation However, the universe we can see came from a single Big Bang event. That doesn't work. If there is an even distribution of matter around the universe (and it would have to be evenly distributed because expansion is the same in all directions) then it will have no net effect - the matter pulling to the left will be exactly counterbalanced by the matter to the right (and so on for all directions). Newton proved this a long time ago! That almost certainly won't happen. Nearly all of the matter in the galaxy will continue to orbit without being affected by the black hole (which only makes ups tiny amount of the matter in the galaxy). The gravity of black holes behaves just like any object of similar mass. One the gas and stars around the black hole have been absorbed then there will be nothing else for it to absorb. Actually, you can treat gravity as space falling into a body like a black hole: http://jila.colorado.edu/~ajsh/insidebh/waterfall.html But that's OK because space is not made of anything so it isn't really disappearing or being used up. Not only suggested, but it has now been observed several times. Exciting stuff. This can only happen if the black holes are in orbit around each other. It is a pretty rare event.
  8. 1 point
    Found it while I was working. A deformation on the side of the manderine. It is weird, looks like it wanted to grow a branch of its own. I named him Morangê.
  9. 1 point
    The video interviews on "Closer to Truth" give a number of well-known and Nobel Prize winning physicists' answers to this very question. Here is the summary, introducing the interviews, on the topic "Are the Laws of Nature Always Constant?": Summary: "The laws of nature or physics are assumed to be everywhere the same, on the far side of the universe as sure as on the far side of your house. Otherwise science itself could not succeed. But are these laws equally constant across time? Might the deep laws of physics change over eons of time? The implications would be profound." Here is the link to the video interviews: https://www.closertotruth.com/series/are-the-laws-nature-always-constant
  10. 1 point
    He's a creationist and is manipulating physics concepts to peddle his agenda. The constants that govern nuclear structure had to have been constant or fission either would not have happened, or given the products that it did. We can check spectra from distant stars and see that the coupling constants relevant to those interactions have not changed. We can do precise measurements over some interval to show that the constants are currently not changing. Typically this is the fine structure constant.
  11. 1 point
    To optimise battery life, the ideal usage range is between 20% - 90% charge. Topping it up from any point above 20% is best. Don't fret about running it down to that number, just keep it above it. Keep it plugged in when you are using it and there is wall power available. Just use it as a portable device when it's necessary. I don't know. Edit: I don't think so because it's running off the mains when plugged in. Once the battery is charged it won't draw current again until the voltage drops below a certain point.
  12. 1 point