A Space & astronomy forum. SpaceBanter.com

Go Back   Home » SpaceBanter.com forum » Astronomy and Astrophysics » Astronomy Misc
Site Map Home Authors List Search Today's Posts Mark Forums Read Web Partners

The cosmic horizon.



 
 
Thread Tools Display Modes
Prev Previous Post   Next Post Next
  #1  
Old October 24th 13, 10:08 PM posted to sci.physics,sci.astro,sci.physics.relativity
Tom Roberts
external usenet poster
 
Posts: 344
Default The cosmic horizon.

On 10/24/13 10/24/13 9:32 AM, Jeff-Relf.Me wrote:
The "cosmic horizon" is 47 gigaâ‹…lightâ‹…years away
( and growing exponentially ) and 13.8 gigaâ‹…years ago.


No. It is indeed 13.8GY ago, and is therefore 13.8GLY away. Its distance and age
are growing linearly, not exponentially.


The Cosmic Horizon is an event horizon, where clocks slow to a stop,
due to the nearâ‹…infinite "gravitational eXergy" there-then.


No. The cosmic horizon is merely the boundary beyond which we on earth cannot
observe anything. It is merely a surface, with no physical characteristics
distinguishing it other than distance from earth at a given time. No observer
located there can identify it via any observations other than measuring distance
to earth [#]; clocks behave normally there. Note this is the conventional
wisdom, and implicitly assumes there is no physical feature there (e.g. an
actual boundary of the universe) -- IOW it assumes the universe is (much) larger
than the cosmic horizon; we really have no information on this (we can have none).

[#] which would take them at least 13.8GY.

I have no idea what you mean by "eXergy". When you make up words you cannot
expect other to understand them.


<Here http://en.wikipedia.org/wiki/Black_hole#Alternatives> WikiPedia says: <<

A much anticipated feature of a theory of quantum gravity
is that it will not feature singularities or event horizons
( and, thus, no black holes ).


This is wrong, or at best disingenuous.

The current best guess is that a theory of quantum gravity will explain or
eliminate singularities. Event horizons are expected to remain essentially
unchanged, because they are in a (low-to-modest-curvature) region where GR is
expected to be valid. There are currently some conjectures that event horizons
might be quite different from GR, but those are not well-vetted yet.


Tom Roberts

 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
[WWW] A possible solution to the dark energy, cosmic acceleration and horizon problems Dave Rutherford Research 21 April 26th 11 08:15 PM
Cosmic Snowflakes and Earth's Cosmic Blizzard ( Mini-comet spotter?) Mitchell Jones Astronomy Misc 3 April 12th 07 02:50 AM
Cosmic Snowflakes and Earth's Cosmic Blizzard Craig Fink Space Shuttle 0 April 12th 07 01:26 AM
Cosmic Snowflakes and Earth's Cosmic Blizzard ( Mini-comet spotter?) Craig Fink Astronomy Misc 0 April 10th 07 02:05 PM
Cosmic proton ray 10^14 eV and Cosmic gamma ray 10^14 MeV; 1997, named GRB 971214 [email protected] Astronomy Misc 1 January 26th 06 09:51 AM


All times are GMT +1. The time now is 01:11 AM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2025, Jelsoft Enterprises Ltd.
Copyright ©2004-2025 SpaceBanter.com.
The comments are property of their posters.