Comments on: Gravitational Lensing Measures the Universe http://www.centauri-dreams.org/?p=11560&utm_source=rss&utm_medium=rss&utm_campaign=gravitational-lensing-measures-the-universe The News Forum of the Tau Zero Foundation Thu, 09 Sep 2010 13:23:46 +0000 hourly 1 http://wordpress.org/?v=3.0.1 By: Ronald http://www.centauri-dreams.org/?p=11560&cpage=1#comment-79686 Ronald Fri, 05 Mar 2010 10:10:08 +0000 http://www.centauri-dreams.org/?p=11560#comment-79686 Concerning the 'total' or 'entire' universe, and the multiverse, this is just in at Next Big Future (my other favorite website): http://nextbigfuture.com/2010/03/research-that-considers-multiverse.html I think, however, that there is some confusion concerning the different concepts: observable universe (unto *our* event horizon), total/entire universe (everything, also beyond our event horizon, stemming from the same original Big Bang, and hence possessing the same physical laws), and the multiverse (different universes originating from as many BB events). But the confusion may be entirely mine. For a simple provincial boy like me, being mainly interested in the Local Group or maybe the Local Supercluster, all this is quite mind-boggling ;-) Concerning the ‘total’ or ‘entire’ universe, and the multiverse, this is just in at Next Big Future (my other favorite website):
http://nextbigfuture.com/2010/03/research-that-considers-multiverse.html

I think, however, that there is some confusion concerning the different concepts: observable universe (unto *our* event horizon), total/entire universe (everything, also beyond our event horizon, stemming from the same original Big Bang, and hence possessing the same physical laws), and the multiverse (different universes originating from as many BB events).

But the confusion may be entirely mine. For a simple provincial boy like me, being mainly interested in the Local Group or maybe the Local Supercluster, all this is quite mind-boggling ;-)

]]> By: spaceman http://www.centauri-dreams.org/?p=11560&cpage=1#comment-79664 spaceman Thu, 04 Mar 2010 20:34:50 +0000 http://www.centauri-dreams.org/?p=11560#comment-79664 Perhaps the most significant aspect of this finding is that the value this group measured for the Hubble constant agrees so well with other groups who have used methods of measurement based on completely different physics concepts (Cepheid variables, supernovae, etc.). This essentially means that we are zeroing in on the actual value of the Hubble constant after decades of hard work and lingering uncertainty surrounding this fundamental parameter. I agree with those who maintain that we have learned much about the large scale structure and evolution of the Universe, but we still have many mysteries left to solve. Great work my friends! Perhaps the most significant aspect of this finding is that the value this group measured for the Hubble constant agrees so well with other groups who have used methods of measurement based on completely different physics concepts (Cepheid variables, supernovae, etc.). This essentially means that we are zeroing in on the actual value of the Hubble constant after decades of hard work and lingering uncertainty surrounding this fundamental parameter. I agree with those who maintain that we have learned much about the large scale structure and evolution of the Universe, but we still have many mysteries left to solve. Great work my friends!

]]> By: Ronald http://www.centauri-dreams.org/?p=11560&cpage=1#comment-79611 Ronald Tue, 02 Mar 2010 23:09:47 +0000 http://www.centauri-dreams.org/?p=11560#comment-79611 'Size of the universe', I presume, means the size of the *observable* universe, not the entire universe (also including everything beyond our event horizon). Could such a method, or another, also give us an idea about the size of the *entire* universe, for instance by estimating the curvature? Or is this inherently impossible? The only size estimates for the entire universe, that I know of, are purely theoretical and lower bounds (such as 10^23 to 10^26 times the observable universe, based on Alan Guth's inflation theory). ‘Size of the universe’, I presume, means the size of the *observable* universe, not the entire universe (also including everything beyond our event horizon).

Could such a method, or another, also give us an idea about the size of the *entire* universe, for instance by estimating the curvature? Or is this inherently impossible?

The only size estimates for the entire universe, that I know of, are purely theoretical and lower bounds (such as 10^23 to 10^26 times the observable universe, based on Alan Guth’s inflation theory).

]]> By: NS http://www.centauri-dreams.org/?p=11560&cpage=1#comment-79608 NS Tue, 02 Mar 2010 20:17:47 +0000 http://www.centauri-dreams.org/?p=11560#comment-79608 The Planetary Society has a podcast on a study that uses gravitational lensing (stars occulting other stars) to detect planets. If I understand right, in this technique the planet(s) are orbiting the foreground star, which causes a measurable distortion in the lensed image: http://planetary.org/radio The Planetary Society has a podcast on a study that uses gravitational lensing (stars occulting other stars) to detect planets. If I understand right, in this technique the planet(s) are orbiting the foreground star, which causes a measurable distortion in the lensed image:

http://planetary.org/radio

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