<div dir="ltr"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><span style="font-family:arial,sans-serif">On Sun, Aug 20, 2017 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"><font size="4">
><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">></div>You can't go to infinity in all directions, the past is a specific finite<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">n</div>umber, 13.8 billion years, the future is unknown and could well be<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>infinite but almost certainly is not equal to the past, it is not 13.8<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>billion years.</font></blockquote>
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<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">> </div>Well I would say at the scale of about 3 billion lightyears, structures<br>
stop being apparent and the universe becomes of sufficiently homogenous<br>
density for my calculation to be valid. </blockquote><div><br></div><div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><font size="4">In the past direction 3 billion years ago things were a little closer together than they are now but otherwise stuff looked more or less the same as now, but go back much further and that is not the case. 6 billion yeas ago the universe was decelerating not accelerating as it is now, and 12 billion years ago stars were much bigger and galaxies were much smaller and more irregular than now, and 380,000 years after the Big Bang when the cosmic microwave background radiation was emitted that we can still see the universe was a billion timed denser than it is now.</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"><font size="4">That doesn't sound very homogeneous and that's just in the past direction. What will the universe look like in 12 billion years? The past direction is finite, is the future direction finite too? Nobody knows. </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>If you include the entire "contents of the 4-D ball" you'd be including<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>events outside our past lightcone that can not influence any observation we<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>make, so that can't explain the observations we can make of Dark Matter or<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> </div>Dark energy.</font></blockquote>
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<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">> </div>Blackhole singularities are outside our light cone as well, hidden behind<br>
event horizons to protect causality, yet they nonetheless influence the<br>
shape of space-time </blockquote><div><br></div><div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><font size="4">The singularity at the center of a Black Hole is outside the light cone but the event horizon and the intense gravitational field there is not, it can influence things far away but, like everything else, only at the speed of light. Physics can't say what the Singularity is doing but it doesn't need to if you're only interested in things outside the event horizon. </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>I claim the same privilege for superluminal space-noodles of dark matter.<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"> [...] </div>The dark matter is superluminal relative to our rest frame.</blockquote><div><br></div><div><span style="font-size:large">Whatever Dark Matter is one thing we know for sure is it's not</span><div class="gmail_default" style="font-size:large;font-family:arial,helvetica,sans-serif;display:inline"> </div><span style="font-size:large">superluminal</span><div class="gmail_default" style="font-size:large;font-family:arial,helvetica,sans-serif;display:inline">, </div><span style="font-size:large">in fact it's very slow; recent studies show it's less than 54 meters per second</span><div class="gmail_default" style="font-size:large;font-family:arial,helvetica,sans-serif;display:inline"> </div><span style="font-size:large">.</span><span style="font-size:large">So I guess you could say 120 mph is the speed of dark:</span><br></div><div><br></div><div><span style="color:rgb(51,51,51);font-family:'PT Serif';font-size:15px;line-height:21px"><a href="https://arxiv.org/abs/1309.6971">https://arxiv.org/abs/1309.6971</a><br></span></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>They can gravitationally warp space-time and according to GR, that's just<br>
geometry. To say gravity is subject to causality is like saying an<br>
elephant's trunk causes its ass.<br></blockquote><div><br></div><div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><font size="4">Even gravity can't cause thing to change at arbitrary distances instantaneously, if it could gravitational waves could not exist. If you suddenly pushed the sun sideways the Earth would not change its orbit in the slightest for about 8 minutes because even gravity and the spacetime distortions it causes is limited to the speed of light. </font></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><font size="4"><br></font></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><font size="4">John K Clark</font></div><font size="4"><br></font></div><div><br></div><div><br></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"><br></blockquote></div></div></div>