[ExI] blown mind

[BillK]

On Fri, Sep 28, 2012 at 5:17 AM, spike wrote:
> Just take a few minutes and gaze at this picture:
>
> http://www.spacetelescope.org/static/archives/images/large/heic1214a.jpg
>
> And while you are doing that, ponder this: the typical spacing between
> galaxies is on the order of a million light years.  Then gaze at this
> picture again.  There are about 8 foreground stars, but all the rest of
> those little smudges are unimaginably large numbers of star, each of which
> is large enough in itself that the mind boggles.  Does that blow your mind,
> or what?
>
>

Ethan has a post up now explaining how the photo was made and what it
is showing.

<http://scienceblogs.com/startswithabang/2012/09/28/the-deepest-view-of-the-universe-ever/>

Quote
If we apply these results to the entire sky, we find that there are
more like 200 billion galaxies in the entire Universe, around double
what we got from the HUDF.

But........
We’re taking a region of space that has very few nearby galaxies, or
galaxies whose light takes less than a few billion years to reach us.
We’ve selected a deliberately low-density portion of the nearby
Universe. The XDF has found many more galaxies whose light has
traveled between 5 and 9 billion years to reach us, which are
relatively dim galaxies that the HUDF simply couldn’t pick up. But
where it really shines is in the early Universe, at finding galaxies
whose light has been on its was for more than 9 billion years, finding
the majority of new galaxies there.

But even the XDF is not optimized for finding these galaxies; we’d
need an infrared space telescope for that, which is what James Webb is
going to be. When that comes around, I wouldn’t be surprised to find
that there are maybe even close to a trillion galaxies in the
Universe; we just don’t have the tools to find them all yet.
----------------------

Note. That's *galaxies* he's talking about! Not just stars. Scale up
again for stars!

Also, See the Hubble report
<http://hubblesite.org/newscenter/archive/releases/2012/37/image/a/>


BillK