Hubble ultra deep field - beyond the big bang

diondrechsler

was just reading about the hubble ultra deep field photo / life the universe etc; here

http://en.wikipedia.org/wiki/The_Universe


they re saying they can photograph the universe to 13billion light years distant / back in time (hubble photo caption a little way down says "Hubble Ultra Deep Field image of a small region of the observable universe, near the constellation Fornax. The light from the smallest, most redshifted galaxies originated roughly 13 billion years ago"

as the cameras evolve they re saying they ll be able to go back further, so...

a) will they be able to take a photo of the big bang? why / why not?

b) now if we think of the big bang as a point in space and not in time for a second... the universe is 93 billion light years across but the big bang only happened 13.7billion years ago so things are speeding away from us faster than the speed of light on the other side of the point at which the big bang occurred ... will we never be able to take a photo of anything that side of the big bang no matter how far our telescopes can zoom simply because everything's moving away faster than the speed of light,- or - because photographing before / beyond the big bang is an impossibility because nothing s meant to exist before it..? does the big bang as a time event get in the way of a telescopes physical zoom power - what would a telescope that could zoom 50billion light years see, and what would be stopping it if it could see nothing?



ha and if you can answer that question you probably deserve an award in astronomy and cryptography... cheers

DM

What makes you think there is another "side of the point at which the big bang occurred"? The singularity at which the big bang derived from is still not understood today, let alone having another side. The problem is that nothing can travel faster than the speed of light. Hence why should the big bang have expanded at a speed greater than light?

mgb_phys

You can't say anything about before the big bang - there was no time so nothing can happen.
The universe however can expand faster than the speed of light, and did so during the infaltion stage - relativity just says that no information can travel faster than light, there is no problem with a universe exapanding faster than this.

BoomBoom

I believe conventional cosmology describes a threshold in which recession speeds are too great for the light emitted to ever reach us....and I think current technology is right at the cusp of that threshold?

If we could see galaxies 50 billion light years away, I think they would have to, at least, re-evaluate the presumed age of the universe.....among other things. :)

mgb_phys

Correct the universe is around 14GYr old - so we can only see things less than 14G light years away - this is the obeevable universe, although the distance we can see is expanding by a light year every year!
The universe is larger than this because of the inflation stage early in it's life, we can't see most of the universe.

In a sense we can already see back to the big bang, in that we see the microwave background - this is the point at which the universe became transparent, so it is impossible to see anything before this.
Improved technology does let us see more distant galaxies, or those that formed earlier after the big bang but this is limited by the age/time at which the first galaxies formed.

russ_watters

Magnification and time depth of field are unrelated except insofar as distant objects are smaller. But even a backyard telescope (a good one) has enough magnification that it could see most of the galaxies in the HUDF -- if it were able to gather enough light. And that's the limiting factor. It's not magnification, it's light gathering. You don't "zoom to" a distance, you take a longer exposure to capture dimmer (and thus more distant) objects.

russ_watters

Just to clarify a little, this thinking is a biproduct of the concept of the Big Bang being like and explosion, where we are somewhere away from a center and there is another side beyond it. But since the Big Bang happened everywhere at once, there is no center, or rather, any point can be seen as a center. So there is no "other side" to look to. The universe looks the same in every direction.

yenchin

Can telescope even see pass anything before matter-radiation decoupling time?

diondrechsler

wow every answer brings about twenty more questions thanks though alot of that made sense


cheeeeeeers

monkeymoney

I have a couple of thoughts to share. One if you think of the "other side" of the big bang as that being problematic for photographing, what about "THIS" side? Why not aim the Hubble in the direction we are going, that way we wont have so far to look because we have been traveling in the same direction. MUCH shorter considering how far we have traveled since earth was created.
Second, and more importantly, most people are missing one very important concept about the big bang. Most see that as some kind of a beginning. However I believe that before the big bang was.... the previous big bang and collapse and before that another big bang and collapse. This current expansion is just one of millions or billions that have happened over "time". What 'cha all thing of that?
Monkeymoney

russ_watters

You are under the very common misconception that the universe has a center. It does not. So there isn't a "this side" or "other side" or a "direction we are going".

monkeymoney

I Russ, Actually I don't think that the universe has a center. I was posing that as more of a hypotherical to the person that posted about photographing the "other side" of the universe as being problematic because of the expansion at near the speed of light. Asking about "our" side as being the alternative that might work was just to open up that concept as negating his concept, or rather opening up the question as to why we couldn't photograph our side.
There are obviously things we just don't know and probably just can't comprehend. I certainly can't. Appreciate your comments though.
Oh and I don't believe that the big bang was the start of everything. If there was a big bang, it wasn't the first.
Monkeymoney

Chronos

Decoupling [~380,000 years post BB] is the photonic limit of observation. A neutrino telescope, however, could 'see' almost all the way back to the BB. Building such a telescope is, however, a challenge. Observational evidence for a BB as the 'beginning' of this universe is overwhelming. It is possible this has happened before [re: cyclical universe], but, no evidence or way to test this idea has been proposed. Until such time, it is pure speculation IMO.

Cryptonic26

I fall into the category as some of the other folks as not being fully capable of understanding the concept that the universe does not have a center.. I mean, all objects have a center of mass, so too should the universe?

Therefore, if all objects in the universe are expanding away from one another, then the universe is essentially expanding from it's center of mass (at least from an external perspective)... Isn't it?

Bottom line, I think most of us uneducated folks assume that light takes longer to traverse between the two most distant objects in the universe with each passing second, so if we face in one particular direction (the direction towards the edge of the universe we are closest to), we should see more up-to-date images, while if we turn around, we should see images that are aging slower than the rest of everything else. Or at the very least, more red-shifted.

Or is this going to start a circular/toroidial universe theory debate here?

russ_watters

That's an incorrect analogy because the universe is not a simple 3d object. That's why the balloon analogy, of a 2d object expanding in a 3d space is used. The surface of the balloon has no center. Nope.

neutralseer

There are a few errors early in this thread:

Yes the universe is ~14Gyr old, but we can see things that are farther than 14G light years away! Distance is tricky thing in cosmology, but when you look at light that was emitted ~14Gyr ago (e.g. the CMB), the thing that emitted the light 14 Gyr ago we are now seeing is currently farther away than 14G light years due to the expansion of the Universe.

Furthermore, the boundary of the observable universe (the particle horizon or the light horizon) is not expanding at the speed of light.


This doesn’t contain any technical mistakes, but it does give one an incorrect idea. The incorrect idea is that two points in the universe could only have faster than light recessional “velocities” relative to each other during inflation (a period of exponential expansion that occurred within the first few fractions of a second after the big bang). While it is correct that faster than light recessional velocities occurred during inflation, it is also true that faster than light recessional velocities are occurring now. We can see galaxies that are currently receding from us faster than the speed of light!

For a non-technical relaxing Scientific American article you can curl up by fire with, I highly recommend this article. It explains more about these common misconceptions of the big bang (it’s the article that marcus--an Astro/Cosmology guru--has at the bottom of every post).

Cryptonic26

So you believe that if you keep traveling in one direction, you'll eventually arrive at the point where you began? If this were the case, then I can understand the analogy-- but I'm not convinced that this is the case, so I have difficulty with the balloon analogy.