<div dir="ltr"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><span style="font-family:arial,sans-serif">On Sat, Nov 4, 2017 at 1:47 AM, Stuart LaForge </span><span dir="ltr" style="font-family:arial,sans-serif"><<a href="mailto:avant@sollegro.com" target="_blank">avant@sollegro.com</a>></span><span style="font-family:arial,sans-serif"> wrote:</span><br></div><div class="gmail_extra"><div class="gmail_quote"><br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
> All paths leading up to the first instant of time are equally invalid<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>because there were none. </blockquote>
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How do you know that?</blockquote><div><br></div><div><font size="4"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">Are you asking how I know the first is the first?</div> </font></div></div></div><div class="gmail_extra"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
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>> <font size="4"> in the case of the universe, all those stop watches started at the<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>same time and in the same place.<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> But</div> to measure a time interval both a start and stop point is needed and<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>all those stopwatches stopped at different times because there is no<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>universal agreement on simultaneity, so there is no agreement on if watch X stopped before watch Y or watch Y stopped before watch X.</font></blockquote>
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<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">> </div>Ah but there is a universal agreement on simultaneity - a precise<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>mathematical definition given by special relativity </blockquote><div><br></div><div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"><font size="4">That is incorrect. There is </font></div><font size="4">universal agreement<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> on the spacetime distance between 2 events but there is no </div>universal agreement<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> on the spacial distance between the 2 events nor is there agreement on the time interval between the 2 events or even agreement on if event X happened before Y or Y happened before X.</div></font></div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">> </div>All events equidistant from the observer that lie in the hyperplane will<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>occur simultaneously </blockquote><div><br></div><div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><font size="4">That is not universal agreement. Yes you can always find 2 observers that agree, but I can always find one that doesn't, in fact I can find an infinite number of them.</font></div></div><div><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">></div><font size="4"> And to make things even<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>worse the stopwatches are running at different rates. So there is no<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>universal agreement on when the Big Bang happened; right here right now<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>we say it was 13.8 billion years ago, but others would disagree</font></blockquote>
</blockquote><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><br></blockquote><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">> </div>Under the assumption that we are the stationary observer,</blockquote><div><br></div><div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><font size="4">Would an observer in the Coma Cluster be willing to make that assumption? Why are we more important than him even from his point of view?</font></div></div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"> <div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">> </div>then our<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>measurement of 13.8 billion years is the maximum observable age of the<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>universe</blockquote><div><br></div><div><font size="4"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">Perhaps so if the universe were to come to an end today. </div> </font></div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">> </div>and all the moving observers will measure a younger universe<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>whose clock is moving slower than theirs.<br></blockquote><div><br></div><div><div class="gmail_default"><font size="4"><font face="arial, helvetica, sans-serif">If you and I are moving relative to each other I will see your clock moving slower than my clock and you will see my clock running slower than your clock. There is no contradiction in this because when we try to measure how long it takes for one of us to move between 2 points we don't agree on when to start and stop the stopwatch. It's a good thing there isn't </font>universal agreement on simultaneity, if there were physics would be logically inconsistent. </font></div></div><div><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">> </div>Of course, we can't actually be stationary relative to the big bang<br></blockquote><div><br></div><div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"><font size="4">We can't be moving away from the spot where the Big Bang happened because it happened right here, it's just that the spot keeps getting bigger with time.</font></div><font size="4"> </font></div><div><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">> </div>because at the very least we are moving away from it in time. This<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>suggests the universe could be far older than we measure it to be.<br></blockquote><div><br></div><div><font size="4"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">I don't know what you mean by that.</div> </font></div><div><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">> </div>Furthermore the universe as whole is significantly larger than the<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>observable part of it, then<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>there are parts of the universe for which our<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>"big bang" has not yet happened.</blockquote><div><br></div><div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><font size="4">I don't understand that either.</font></div></div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><font size="4">
> <div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">> </div>There are a infinite number of ways a bunch of distant clocks can be<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>brought together in a expanding universe, and I don't see how everyone<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>could agree on how to do it. Should distant clock X be brought to clock Y<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>or should clock Y be brought to clock X It makes a difference because<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>one clock would be accelerated and the other clock would not and a accelerated clock runs slower than one in a inertial frame of reference.</font></blockquote>
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<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">> </div>Why would you bring the clocks back together again? Just read the distant<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>clocks through a telescope and adjust for relative velocity and distance.<br></blockquote><div><br></div><div><div class="gmail_default"><font size="4"><font face="arial, helvetica, sans-serif"></font>I don't see what the point of that would be, we already know what we'd see through our telescopes, we'd both see a stopwatch running slower than our own. And if I am going south at half the speed of light and you are going north at half the speed of light and I watch you through my telescope measure the time it takes you to pass mile markers on the road I will see you write in your notebook the same figure that I do even though I see your stopwatch running slow, because from my viewpoint you started and stopped your stopwatch at the wrong times. We don't agree on simultaneity, we don't agree on the instant you passed the 2 mile markers.</font></div><div class="gmail_default"><font size="4"><br></font></div><div class="gmail_default"><font size="4">If you bring the clocks together to find out which clock was *really* running slow the symmetry of the situation will be broken because one must accelerate and one must not. If you accelerate back toward me you will see my clock running FASTER than your clock and I will see your clock running SLOWER than my clock. When you get back to the same place I'm at and we're moving at zero speed relative to each other we will both observe both clocks again running at the same rate but they will no longer be synchronized, we will agree that much more time has passed on my clock than your on clock because your clock was accelerating but mine was not. The same thing would happen if instead of accelerating you were in a stronger gravitational field than me. </font></div></div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">> </div>The way I am hypothesizing it happens is that everything we can see is<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>inside a hollow sphere of infinite thickness and constant density and thus<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>infinite mass. And so everything in the sphere is being gravitationally<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>pulled to the closest part of the sphere because the infinite mass of the<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>universe is just a little closer in that direction.<br></blockquote><div><br></div><div><font size="4"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">Infinite</div> thickness? Be careful, there Be Dragons. If I'm standing on the inner or outer surface of a sphere with an<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> i</div>nfinite radius<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>the surfaces<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>will both look the same to me,<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>they<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>will look like I'm standing on a infinitely flat infinity large plane, and the gravitational acceleration produced by such a plane is 2*π*G*D*H,<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>where G is the gravitational constant, D is the density and H is the thickness of the plane. A derivation of this formula can be found in volume 1 of The Feynman Lectures On Physics, in section 13-4 called "Gravitational field of large objects".<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>There are 2 interesting things to see from that formula:</font></div><div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"><br></div></div><div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"><font size="4">1) Unlike a point source or a finite sphere the gravitational field does not decrease with the square of the distance, in fact for a infinite sphere or infinite plane the gravity does not decrease at all for any finite distance. </font></div></div><div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"><br></div></div><div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"><font size="4">2) If it's infinitely thick then H is infinite so if D, the density, is not zero then the g force on the surface will be infinite and not just on the surface, it will be infinite everywhere. Needless to say we do not observe that.</font></div></div><div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"><br></div></div><div><font size="4"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">And even if the sphere is not infinite but just astronomically large </div>I don't see how <div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">that idea </div>can explain why the universe was decelerating for the first 9 billion years of its existence and only started accelerating 5 billion years ago. It's also odd that the Earth happens to be at a very untypical place, the center of a infinite sphere. It all seems a bit too Ptolemaic.</font><span style="font-family:arial,helvetica,sans-serif"> </span></div><div><div class="gmail_default"><br></div></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><font size="4">
><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">></div> And that percentage will increase as time passes because both normal matter<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>and dark matter will keep getting diluted but dark energy will not, the<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>more space that space itself creates<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>he more dark energy there is <div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">but</div> the amount of matter in the universe <br>will be constant.</font></blockquote>
<br><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">> why </div>would you insist that matter be conserved but that energy is not?<br></blockquote><div><br></div><div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><font size="4">I don't insist on matter being conserved but not energy, but for the last 20 years we've have lots of empirical evidence that the universe does insist on exactly that. As to why the universe prefers things that way you'll have to ask the universe not me.</font></div></div><div><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">> </div>Both Hawking radiation and radioactive decay are adding particles to the<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>universe. </blockquote><div><br></div><div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><font size="4">So what? That in no way changes the fact that as the universe expands the mass of matter in the universe, both dark and regular, becomes more and more diluted but Dark Energy does not because unlike matter Dark Energy is a property of space itself.</font></div></div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">While it would seem at first glance that fusion decreases the particle<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>number of the universe,<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>when one considers photons and neutrinos as<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>particles, it is clear that fusion too increases the particle number ofthe universe.</blockquote><div> </div><div><font size="4"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">True</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">, when 3 protons fuse they produce 4 particles, a positron a neutrino a gamma ray and a Helium-3 nucleus, but the number of particles is irrelevant from a cosmological perspective, but the total mass/energy is not and the fusion process does not change that. </div></font></div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"> when one considers photons and neutrinos as<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>particles, it is clear that fusion too increases the particle number of<br>
the universe.<br></blockquote><div><br></div><div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><font size="4">Fusion or no fusion the mass/energy content of the hydrogen remans constant, <span style="font-family:arial,sans-serif">Hawking radiation or no </span><span style="font-family:arial,sans-serif">Hawking radiation</span><span style="font-family:arial,sans-serif"> </span>the mass/energy content of a Black Hole remans constant; but as the universe expands the <span style="font-family:arial,sans-serif"> </span>mass/energy content of Dark Energy does NOT remain constant.</font></div></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">> </div>So if the number of particles is increasing and they have relative<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>velocities and therefore kinetic energy, it is clear that the mass of the<br>
universe must be increasing.</blockquote><div><br></div><div><font size="4"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">No that is not clear at all. The number of neutrinos is certainly increasing but as they have AT LEAST 45 billion times less mass than a proton that fact is not very important. </div><span style="font-family:arial,helvetica,sans-serif">The mass of matter is not increasing,<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> the amount of Dark Energy is.</div></span></font></div><div><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">> </div>But if energy is conserved<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> [...]</div></blockquote><div><br></div><div><font size="4"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">On a cosmological scale energy is not conserved in a expanding accelerating </div>Einsteinian <div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">universe.</div></font></div>
<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">> </div>Obviously, as the particle number and volume of the universe increases, so<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>too will the entropy. Since those particles will have more degrees of<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>freedom available to them.<br></blockquote><div><br></div><div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><font size="4">I agree.</font></div></div><br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">> </div>It is not the conservation laws that are the contortions but the<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>cosmological constant, dark energy and dark matter. They are like<br>
epicycles. No need to make the universe more complicated than it already<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>is.<br></blockquote><div><br></div><font size="4">Einstein said theories should be as simple as possible but <div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">not</div> simpler. I admit the physical theories we have today are a bit of a mess but if somebody can come up with a simpler idea that can explain the rather<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>bizarre<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>observations we've been seeing<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>recently<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>I'm sure it would be embraced with enthusiasm, but that won't be easy. For example, some have proposed getting rid of Dark Matter by modifying the laws of gravity, but no modification can explain galaxy<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>Dragonfly 44. From the motion of stars and the orbits of globular clusters in orbit around<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>it we know that<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>Dragonfly 44<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>has about the same mass as our galaxy, a trillion solar masses, and yet<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>Dragonfly 44<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>has little gas or dust and less than 1% as many stars as the Milky Way does, it is one of a new class of objects called "dark galaxies". Unless there is no universal law of gravity at all because it works differently in dark galaxies than in normal galaxies like ours the only conclusion is that 99.99% of the matter in<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>Dragonfly 44<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>must be dark verses only 88% for the Milky Way.</font><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">> </div>The acceleration of the universe is just the curvature of spacetime in the<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>outward direction caused by the mass density in all the other causal<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>cells. Come on, acceleration, curvature, and gravity are all synonomous.<br></blockquote><div><br></div><div><font size="4"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">But we now know that mass alone can not explain the large scale shape of spacetime, and even mass and pressure is not sufficient to do so because tension caused by Dark Energy is also a factor, and in fact the most important factor.</div> </font></div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">> </div>It's just the equivalence principle and Einstein came up with that. Not<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>me.<br></blockquote><div><br></div><div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><font size="4">The <span style="font-family:arial,sans-serif">equivalence principle is still true, spacetime still tells matter how to move, its just that we now know that matter is not the only thing that tells spacetime how to curve, Dark Energy also has a say in how spacetime should curve.</span></font></div></div><div><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><font size="4">
><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">></div> The density of normal matter and Dark Matter has decreased over time but<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div> it has become clear that the gravitation caused by matter alone (not<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>even with the help of dark Matter) is insufficient to explain the<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>evolution of the universe. For a very long time the expansion of the<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>universe was slowing down just as you'd expect, but about 5 billion years<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>(and nearly 9 billion year after the Big Bang) the deceleration<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>stopped and things started to accelerate. This can only be because the<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>matter became diluted and so did the gravitational force trying to slow<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>things down but some property of space itself called Dark Energy which<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>nobody understands causes things to speed up, so whatever it is when there<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>is more space there is more Dark Energy </font></blockquote>
<br>
<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">> </div>Where is the evidence that the universe has been decreasing in density?</blockquote><div><br></div><div><div class="gmail_default"><font size="4"><font style="font-family:arial,helvetica,sans-serif"></font>The evidence has been known since 2003. For the first 9 Billion years of its existence the expansion of the universe was slowing down, but about 5 billion years ago that changed and it started to speed up because the amount of matter (both dark and non-dark) that was trying to slow thins down became more dilute as space expanded but the amount of Dark Energy trying to speed things up did not become more dilute due to the fact that Dark Energy is a property of space itself.</font></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><a href="http://iopscience.iop.org/article/10.1086/383612/meta" target="_blank">http://iopscience.iop.org/arti<wbr>cle/10.1086/383612/meta</a> </div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><a href="http://www.nytimes.com/2003/10/11/us/a-cosmic-jerk-that-reversed-the-universe.html" target="_blank">http://www.nytimes.com/2003/10<wbr>/11/us/a-cosmic-jerk-that-reve<wbr>rsed-the-universe.html</a><br></div></div><div><br></div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"> <div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">> </div>If<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>space-time is expanding and the particle number of the universe is<br>
increasing, then density could be going up.<br></blockquote><div><br></div><div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><font size="4">The number of particles is irrelevant, the total mass of all those particles is not and that total mass of matter remains constant, but the amount of space those particles can be in is not constant if space is expanding so mass is becoming more dilute. And if Dark Energy is a property of space itself then it is not becoming more dilute as space expands. Matter tries to slow the expansion and Dark Energy tries to speed it up, for 9 billion years matter won that tug of war but then it just got too dilute 5 billion years ago and Dark Energy started to win.</font></div></div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">> </div>What I am saying is that spacetime cannot curve away from a<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>mass without curving toward some other mass somewhere.<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"></div></blockquote><div><br></div><div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"><font size="4">Curved 4D spacetime can be defined without the need for a fifth dimension or anything else for it to curve into. Curved spacetime just means the Euclidian distance formula, aka the Pythagorean Theorem, will not work there but Einstein provided a distance formula that will. </font></div></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"></blockquote><span style="font-family:arial,helvetica,sans-serif"></span><br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">> </div>What's outside of our light-cone? Literally almost *everything*.<br></blockquote><div><br></div><div><font size="4"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">Maybe everything maybe nothing, it's outside our light-cone so we can never know. </div> <div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"></div></font></div><div><font size="4"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"><br></div></font></div><div><font size="4"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">John K Clark</div></font></div><div><font size="4"><br></font></div><div><font size="4"><br></font></div><div><br></div><div><br></div><div><br></div><div><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><br></blockquote></div></div></div>