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Actually, while the universe as a whole may be limitless, we are
actually likely stuck in a finite patch.<br>
<br>
The reason is the accelerating expansion. Even if we spread at light
speed we could only reach 15 billion light years away ("the
affectable universe" in Toby Ord's terminology). That is still 6.5
billion galaxies and much larger than the 300 million lightyears
"end of greatness" homogenity scale (Laniakea is just 260 million
and the Virgo cluster just 7 million lightyears). <br>
<br>
The 46 billion lightyear radius of the currently observable universe
is expanding with time, and will eventually reach 62 billion
lightyears. But that is relative to Earth: were we to expand across
the affectable universe we would add 15 billion lightyears in all
directions - things that can be seen by the colonies, even though
the information can never reach Earth. <br>
<br>
Note that if you want to exchange an infinite number of signals from
the frontier to your core you will be stuck in a gravitationally
bound supercluster, a few million lightyears across. <br>
<br>
So our future universe may be unbounded in time, but not in space. <br>
<br>
(A lot of these measures need defining in a bit more detail, since
we are dealing with expanding coordinate systems; I have used
co-moving spatial coordinates here, since they are the most
reasonable when you care about the material stuff inside the
universe.)<br>
<br>
<div class="moz-cite-prefix">On 2016-03-23 08:11, Dan TheBookMan
wrote:<br>
</div>
<blockquote
cite="mid:771D2C8E-0868-43C1-AD84-874D0C552DDC@gmail.com"
type="cite">
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<div>On Mar 22, 2016, at 1:14 PM, BillK <<a
moz-do-not-send="true" href="mailto:pharos@gmail.com"><a class="moz-txt-link-abbreviated" href="mailto:pharos@gmail.com">pharos@gmail.com</a></a>>
wrote:</div>
<div>Sort of linked....... :)</div>
<blockquote type="cite">
<div><span></span><br>
<span><<a moz-do-not-send="true"
href="https://briankoberlein.com/2016/03/22/beyond-the-universe/">https://briankoberlein.com/2016/03/22/beyond-the-universe/</a>></span><br>
<span></span><br>
<span>Quote:</span><br>
<span>the known universe is about 93 billion light years in
diameter. As</span><br>
<span>large as that is, it’s only the portion of the Universe
we can</span><br>
<span>observe. The total Universe extends beyond our horizon.
Just how far</span><br>
<span>it goes is an interesting question.</span><br>
<span></span><br>
<span>There are indications that the Universe extends far
beyond what we can observe.</span><br>
<span></span><br>
<span>the short answer for the size of the Universe is that
it’s huge.</span><br>
<span>Likely very, very, very huge. Possibly infinite.</span><br>
</div>
</blockquote>
<div><br>
</div>
I still default to infinite. ;)<br>
<br>
<div>
<div id="AppleMailSignature">
<div style="line-height: normal;"><span style="line-height:
20px; background-color: rgba(255, 255, 255, 0);">Regards,</span></div>
<div style="line-height: normal;"><span style="line-height:
20px; background-color: rgba(255, 255, 255, 0);"><br>
</span></div>
<div>
<div style="line-height: normal;"><span style="line-height:
20px; background-color: rgba(255, 255, 255, 0);">Dan</span></div>
<div style="line-height: normal;"><span
style="background-color: rgba(255, 255, 255, 0);">
Sample my Kindle books via:</span></div>
<div style="line-height: normal;"><a moz-do-not-send="true"
href="http://author.to/DanUst" style="background-color:
rgba(255, 255, 255, 0);"><font color="#000000">http://author.to/DanUst</font></a></div>
</div>
<div><br>
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</blockquote>
<br>
<pre class="moz-signature" cols="72">--
Anders Sandberg
Future of Humanity Institute
Oxford Martin School
Oxford University</pre>
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