I need help in understanding what is written about the expanding universe. They check the red shift on an object 10 billion light years away and conclude that it's moving away from us at a great speed. They check the red shift on an object 5 billion light years away and conclude that it is moving away at a lesser speed. Hmmm?

Since the first gives the speed 10 billion years ago and the second gives the speed 5 billion years ago, wouldn't it be logical to conclude that the expansion has slowed down over time? How do they project an increasing speed of expansion based on a snapshot that is 10 billion years old?

G'day

Thanks Harry. I'll check your references.

Let us see furthur !!!

Thanks for the message Dusty. I checked the references that Harry Costas provided and found them very interesting. What you've shared is pretty much the standard model. It's what the public universally hears but there seems some leeps in logic to me. Hubble is given the credit for discovering that the univers is expanding yet he while allowing that it might be so, didn't accept it as fact. Harry's material gave some insights based on Hubble's papers and lectures.

Hubble discovered the law that red shift increased linearly with distance. It seemed possible to him that light in it's millions of years in transit might lose energy linearly this being exhibited in a red shift. This fits the observations but requires a yet undiscovered physical law. Hubble acknowledged the red shift could be due to Doppler shift coming from radial velocity but did not buy that as fact. He was also troubled by the very high velocities that the red shift would indicate.

The expanding univers and big bang require a lot of 'add ons' that are no more testable than the tired light theory. How do we know that the 'expansion' happened? It had to or the big bang wouldn't have produced the universe we see today. So if we have the big bang and the current universe, we had to have the expansion. We used to calls this "Frank's fudging factor".

 Dusty,

Thanks for your response. I'm pleased that you like the simple explanation for what we observe. I agree. So with red shift there are two assumptions. 1) it's Doppler shift due to radial velocity of the observed sourse. 2) light in transit loses energy at a rate directly proportional to distance traveled.

When assumption 2 is considered, it seems to be consistant with the observed relationship of luminosity and distance.

There is no need for the 'expansion', dark matter, or dark energy, all of which are required for the BB and red shift through Doppler effect.

 When assumption 1 is considered, we have to have expansion of space, not explosion of matter. We have to have the 'expansion' otherwise, the universe couldn't be as it is observed today. We have to have dark energy to accellerate the expansion. We have to have dark matter to keep the galaxy's from expanding with space.

None of these add ons assumptions are any more provable than 'tired light' but are necessary  for assumption 2. They have to be fact for the expanding, accellerating universe to be fact.

From Wikipedia: Occam's razor, also Ockham's razor,^[1] is a principle attributed to the 14th-century English logician and Franciscan friar, William of Ockham. The principle states that the explanation of any phenomenon should make as few assumptions as possible, eliminating those that make no difference in the observable predictions of the explanatory hypothesis or theory.

I need some help with the CMB. The souce of this radiation is the BB which occurred some 13 plus billion years ago? And it's reaching us now? It originated 13 billion light years away in all directions? The universe at that point was hot enough and dense enough in that volume of space to generate that energy? Please help me fit this together.

yawstring:

 Dusty,

Thanks for your response. I'm pleased that you like the simple explanation for what we observe. I agree. So with red shift there are two assumptions. 1) it's Doppler shift due to radial velocity of the observed sourse. 2) light in transit loses energy at a rate directly proportional to distance traveled.

When assumption 2 is considered, it seems to be consistant with the observed relationship of luminosity and distance.

If you Google "tired light" you'll find that idea has been very thoroughly discredited.

... 

I need some help with the CMB. The souce of this radiation is the BB which occurred some 13 plus billion years ago? And it's reaching us now? It originated 13 billion light years away in all directions? The universe at that point was hot enough and dense enough in that volume of space to generate that energy? Please help me fit this together.

The standard model BB holds that the source of the CMB was the BB event. This model also holds that at the event, everywhere that exists today was actually at the same place then ... that is, all parts of the Universe were in contact -- there was no "travel time" needed to get from one place to another.

So, no, it is not "reaching us now" from an origin "13 billion light years away in all directions." Instead, it has been around us all the time and we and it are moving along with what is called the Hubble Flow (plus Guth inflation) since the BB event.

 The Universe is held to have been formed from a singularity or something very like it. Agreed: that is hard to grasp. It does, however, fit the observations in general.

Spacetime then expanded from that point onward and outward. It is the stretching of spacetime (not travel time) that has redshifted the CMB to the temperature and wavelength we see today. The work by Gamow, Alpher, and other BB theorists in the early Twentieth Century predicted that the Universe must be suffused with the afterglow of this spacetime-creation event. At the time of this prediction the technology to detect this radiation did not exist, but the mathematics to predict it did. Some three decades later, when the technology did exist, the radiation was detected (as an accidental by-product of another investigation). Two later spaceborne experiments (COBE and WMAP) refined the earlier observations, confirming not only the temperature and wavelength of the CMB, but also its general isotropy. Measures of its miniscule anisotropies (wrinkles, they're called) has given rise to new theories of galaxy evolution.

If you look at cosmology as a jigsaw puzzle, then the BBT is like the bits of the picture imprinted upon the pieces. To an astonishing degree, as we fit ever more pieces of the puzzle together, the picture that seems to be emerging (via observation and measurement) repeats the patterns both assumed and predicted by the BBT.

You quoted Occam's Razor correctly but applied it to the wrong argument. In addition, if you research what is meant by Theory in a scientific sense, you can find no better exemplar than the BBT.

In gaming circles, with tired light you'd be said to be "betting on the wrong horse" here ...

Dark matter is not a requirement of BB theory.  It is neeed to explain why galaxies and galaxy clusters are much more massive than they visually appear to be.  They also have some proof for it's existence.  

Dark energy is not a requirement of BB theory either.  It wasn't needed until 1998 when they discovered that the universes expansion appeared to be accelerating.  That's the only time a new force "for accelerated expansion" seemed to be needed.  But the BB theory in of itself doesn't require either of these theories.

So far your add ons don't appear to be adding up.

  Yawstring, in response to your original question. I believe it was best explained as you have to imagine the Universe is expanding in all spaces. So if a galaxy is five billion light years away from us, that distance is expanding. Now, let's add another galaxy ten billion light years away on the same plane. That galaxy is in fact expanding away from the middle one AND our galaxy as well. So, the more distant one would appear to be moving faster away. Of course local movements, changes in velocity over time, and differences in galaxy formation that long ago would account for any discrepencies than having to invest in tired light. There's a lot of good information in the book Voyage to the Great Attractor about red and blue shifts, expansion of the Universe. They relied on it to make a rough map of observed galaxies relative distances, really cool stuff.

The Universe is not the one that is expanding but instead is the " LIGHT " that originated from the beginning whaterver that beginning was. The Light is not expanding but merely traveling and filling the void where there are no events taking place. Since Space is one there are other events which are older than our formations and the Space which we occupied along with our other neighbors. Many scientists will like to believe that existence began with a BB cause it's very convinience and allowed for a more simpler explanation this leads them to create all the conditions that suits the BB by explaning and searching for evidence that also fit the model of the BB. The Universe is not just one but many and detached from one another but the BB model will someday say that even such Universes are but the same or from the same beginning it's  just the date of origin thats wrong and that the Universe is much older than they had predicted. Still there is no expansion of Space cause Space does not expand. To say that the Universe is expanding will be like visualizing some form of barrier in front of such expansion. For example, when you asked for a glass of water, the glass can be filled to the rim or you can asked for less. Any other amount will overflow from the glass to avoid the spill you stop but what has been spilled had fallen to some surface. The Universe cannot be expanding and creating space at the same time like if it has a mind of its own. Space is something that is, in other words, Space is NOT A CREATION of some sort. The problem with this is that science wants to fit everything into some order and had jump prematurally to conclude that space is racing along with the light from the very beginning of the so called BB and at some distant point is still expanding -- creating more Space in all directions.