Slashdot Mirror

← Back to Stories (view on slashdot.org)

Deepest Optical Image Of The Universe To Date

Posted by michael on from the asa-eight-million dept.

fenimor writes "The deepest optical view of the universe, obtained by Hubble Space Telescope, may turn out to be some of the earliest star-forming galaxies. The telescope has looked 95 percent of the way back to the beginning of time, to glimpse whether the hottest stars in these early galaxies may have provided enough radiation to 'cool' the universe after the big bang."

4 of 24 comments (clear)

  1. I think you're right by Anonymous Coward · · Score: 2, Interesting

    The Big Bang obviously no longer exists at a single point in space. The residual image is at the outermost edge of the universe. What's the paradox?

  2. Actually, you are correct... by j_cavera · · Score: 5, Interesting

    This is not a paradox, rather just a way of looking at it that is different than what you are used to. The universe at the beginning of time, existed as a point (more or less) that expanded (somehow) into what we see today. As you look out into the universe, you also look back in time. The farther back you go, the smaller the universe was.

    By logic, if you could look all the way back to the big bang itself, you would see a point of light. And this is where your percieved paradox occurs. But this is actually the correct way of thinking about it, because time = distance. So where does that point lie? Everywhere, at a distance of 15 billion (give or take) light-years from us! So no matter where you look, you see a "part of that point" from 15 billion years ago.

    OK, this is an oversimplification as the universe was opaque for some time after the big bang, but you get the idea. Here's a potentially useful (though not perfectly accurate) analogy. Go inside a large spherical room with white walls. Put a bright light bulb at the center (big-bang). The walls are evenly illuminated because no matter which way you look, your line of sight intersects with some of the rays of the bulb, that seem to come to you from all around you.

    In fact, if you had a good enough detector, you could determine the shape of the bulb's filament by irregularities in the light from the walls. This is what the cosmic background explorer (COBE) missions are about.

    BTW, yes IAAP (I am a physicist).

    --
    #include "humorous_pop_culture_reference.h"
    1. Re:Actually, you are correct... by Guignol · · Score: 2, Interesting

      Hi,
      Sorry for the offtopicc, but all seems quiet and since YAAP and seem to know about the stuff I thought I'd just ask :)

      I am wondering if, today, we have some real "expectations" about the universe course from big bang (if big bang there was) to now and if yes, if we have commonly believed aswers (or prefered models about this) about the following assumptions that I make myself when trying to imagine the whole picture:

      - The universe is roughly a 4D sphere, and we belong to its boundary (or the universe *is* this boundary however one wants to view it)
      - At big bang event, this sphere radius was nearing zero and is since then expanding
      - This expansion implies an expansion of the surface which is the "texture of the universe", it's not (not only) the universe elements that fly appart (matter and light) but there is more and more space to be moving around.
      - There can be thus combined expansions:
      we can see matter moving away for whichever reason (forces, initial velocity etc.), but "space" itself while expanding, can move its population around with its expansion. (this latter movement being not subject to physical limitations like speed of light I suppose)
      - However, since I think that we believe that matter is being moved by this space expansion, and since we can still see "things" around us, I suppose this expansion rate is well under lightspeed (at least today, I wonder if we think this speed has been varying since the beginning)

      So, if all of this makes sense, my idea, and main question is this:
      at one point, we could have had an universe large and old enough to see stars and galaxies forming, yet (maybe) small enough to be fully explorable in a fraction of the time given from them until now.
      (I mean that, at this time we could have started exploring the universe in a straight line and come back (since it's spherical) before (or at most until) today (travelling at lightspeed).
      Then, a star (or something brighter, like a group of galaxies) would send its light in a spherical way fast enough to reach the "Universe equator" and start contracting back to until reaching the oposite pole of the universe and from there expand back again (even self interfering on a surface which would be defined as a matter of the lifetime of said light source and the expansion speed of the universe).
      Is that correct ? if not why not ?
      If yes, couldn't be today witnessing such things like mirror effects ?
      I'm asking this because if indeed we believe having covered 95% of the whole universe and if those conditions are plausible, then maybe we can see "mirror effects". The mirror effects would be of different natures according to several considerations:
      We should see the mirror effect of lightsources that "were coming from some point at some time, and which appear from the oposite direction in the exact same (inversed) way at a precise later time. Those Timings and directions being influenced by our observer's relative position to an original source and "where was 'its' equator" ('its' because we all have one) then and now.
      Now, I am realy wondering how we could even tell an original from its mirror...
      and there are also two kind of incoming lights which must be somthing specal to see: expanding light versus contracting light. I suspect seeing contracting light coming to us (if we are on the other side of this particular source equator at the time we received its light) the we must be "feeling" it comes from another direction.
      Just like mass can deflect light, exept this would be then be very exessive bending.
      Now, if we are able to guess today's size of the universe, its expansion speed during the time and age of galaxies, couldn't a 95% map of the universe give us some definite clues about its very shape ?
      That is, if we witness those mirror effects, or if we should but don't, or if in some region the mirrors are "too late" or "too scatered" etc. couldn't we infere that; for instance, the universe is in fact, say,

  3. Re:We were part of the big bang too. by luna69 · · Score: 2, Interesting

    > The matter that makes up the Earth, you and I, the
    > sun, our Galaxy, was all part of the explosion we
    > call the Big Bang.

    Well, yes, and no. "The matter" was indeed formed during the big bang (well, shortly after it, during nucleosynthesis). But only Hydrogen, Helium and a little Lithium. The rest of the actual atoms you and I are made of were formed in stellar cores as a result of fusion (for elements lighter than and including Iron) or in stellar supernovae (for all elements heavier than Iron).

    Pretty cool to look at a gold ring on your finger and contemplate its origin in an exploding star.

    See: http://en.wikipedia.org/wiki/Big_bang_nucleosynthe sis

    and

    --
    No gods, no demons, and no masters. Secular Humanism!