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Big bang worries

  1. Dec 8, 2003 #1
    I know that looking back in space is looking back in time. I also know that seeing the Big Bang should be beyond us in space time. I believe that we are on the edge of the bubble, that is space time, If we could see far enough back, or far enough out, we could see the Big Bang. Why or Why not can we not see it? I believe that if we can't, then space travels faster than the speed of light, and if it does not, than we should be able "hypothetically" to see the origins of our own universe. Either way it demonstrates that there might be a power faster than light travel. What does anyone have to say on this?
     
  2. jcsd
  3. Dec 8, 2003 #2
    ...

    The Concept of Space and Time "evolved" only after the Big Bang and I think that it is wrong to say that we should be seeing Big Bang. Everything evolved only from the Big Bang including the photons of light. Thus leaving the instant of creation we are seeing evrything else. The Cosmic Background Radiation is in fact an efect of the Big Bang that we are seeing. We have also spotted galaxies in their formative stage.

    Sridhar
     
  4. Dec 8, 2003 #3
    I think that you may have misread what i said. If IF we could see the big bang why cant we see it. Though the big bang is beyond us in space time as in before us. But when we look out to space we see the past. Elaborate on this problem.
     
  5. Dec 8, 2003 #4
    Are you asking me that if whe are able to look at the (lets go by ur words)THE BIG BANG, then why aren't we able to look into the past???
    Is this the question???
    Well if this is the question, then heres ur answer, What we are looking is not past itself, but, a late viewing of the past because of the non infinite speed of light.

    and If ur question was Why can't we see Big Bang if we could see past, then, ur answer is the same as my previous one combined with the fact that everything began only with the big Bang...

    Have I answered ur question yet???

    Sridhar
     
  6. Dec 8, 2003 #5
    we can t "see" the big bang, because the universe was opaque to light until 300,000 years after the Big Bang. so 300,000 years after Big Bang is the earliest time we can see.

    the light from this time is known as CMB or the Cosmic Microwave Background Raditation. we can see this light, and it is considered some of the strongest evidence that the Big Bang model is correct.

    there are certain other signals for which the universe would have been transparent at earlier times, however. like relic neutrinos, or gravitational waves. so if we figure out some way to measure those signals, then we can use those to "see" times that are much closer to the Big Bang.
     
  7. Dec 8, 2003 #6
    if i look back far enough with a telescope, i should be able to see the big bang if the universe was traveling at light speed, except that the big bang happened before this galaxy was created, and therefore, space should be moving faster than light speed. The light from the big bang should be beyond us except for the fact that the universe is said to be slowing down. if that is the case than we should catch up to the big bang. I don't know when that would happen but that would mean that the universe is in fact collpsing. What do you think?
     
  8. Dec 8, 2003 #7

    jcsd

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    Well first-off you are correct, 'space' does 'travel fastre than light' that is to say that there are objects in the universe that have recession velocities greater than c (recession velocity is not the same as what we normally think of a svelocity as it has to do with the expansion of spacetime and it's important to note that recession velocities greater than c in no way violate the theory of relativity). A redshift greater than 3 corresponds to a superluminal recession velocity and we can actually see far-off objects which are travelling away from us faster than the speed of light.

    The reason why we can't 'see' the big bang is that the early universe was very dense and any photon emitted would be instanly reabsorbed, so the universe was essietially opaque. About 300,000 years after the big bang, over a relatively short period of time, the universes decreasing density became such that photons could be emitted, this is known as the deconfinment era (photons became 'deconfined' from matter thus making the universe transparent). The radiation emitted in this era is what we see as the cosmic microwave backgrond radiation, beyond this era the universe is opaque and we can't see back any further with electromagnetic radiation.
     
  9. Dec 8, 2003 #8
    do you think that this "empty" part of space has anything to do with 90% of dark matter that is unaccounted for
     
  10. Dec 8, 2003 #9
    Why would galaxies furthur away (meaning that they were closer to the big bang) have a higher red shift in they're movement?
     
  11. Dec 8, 2003 #10

    jcsd

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    which "empty part of space"?
     
  12. Dec 8, 2003 #11

    Nereid

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    Just to expand a little on why we can't 'see' the universe any earlier than age ~300,000 years (or redshift of ~1100). With a telescope, you can see the surface of the Sun. However, you cannot see the centre of the Sun. This is because photons (which is what your telescope detects, whether radio, microwave, infrared, light, UV, X-rays, or gammas) below the surface of the Sun are emitted, absorbed, scattered etc and very few emerge from the surface unscathed (so to speak).

    Neutrinos, on the other hand, do travel through the Sun unhindered, so any created in the core can escape without being absorbed, re-emitted, or scattered, and indeed are detected with 'neutrino telescopes'. In this case, however, since we can't focus neutrinos, the image of the Sun is all blurry.

    If neutrino telescopes could detect the relict neutrinos from the post-Big Bang era, we'd see something like the CMB. It still wouldn't be the Big Bang however, because the relict neutrinos come from a time when they were last scattered (etc), and that time is many thousands of years after the Big Bang itself.
     
  13. Dec 8, 2003 #12

    jcsd

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    red shift (which is a measuremnt of the observed frequency of the electromagnetic radiation vs the emitted frequency) is basically a function of how fast something is moving away from us.
     
  14. Dec 8, 2003 #13
    Why do you think that the time between the big bang and the known universe is only 300,000 years.
     
  15. Dec 8, 2003 #14

    jcsd

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    From solutions to cosmological equations.
     
  16. Dec 8, 2003 #15
    you have done you're homework on NGC 7603 yes?
     
  17. Dec 8, 2003 #16
    Red shifts are a calamity.
     
  18. Dec 8, 2003 #17
    how so? o)
     
    Last edited: Dec 8, 2003
  19. Dec 8, 2003 #18

    jcsd

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    Yes I have heard of NGC 7603, but be aware that Walton Arp's ideas on these are far from conventional cosmology and its believd to be an optical illusion like most Arpian objects, due to a chance projection.

    If you were to find two objects of very differnt redshifts with a continous bridge of changing redshift between them, then people might sit up and take notice.
     
  20. Dec 8, 2003 #19
    we have ngc 7603 moving at a redshift of Z=.029, we have the node of the the galaxy (that connects it to object 1) being at a red shift of z=391. we have object 1 moving at a velocity of z=.075 and than we have it's node moving at z=.243. As far as i know this is unexplainable. Please elaborate if you know something that i don't.
     
  21. Dec 8, 2003 #20

    jcsd

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    As I said the most reasonable explantion is that NGC 7603 and NGC 7603b are not connected and are infact very far away from each other, there apparent proxmity is proabbly due to their projection.
     
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