Universe 93 billion light years?

[filegraphy]

(http://en.wikipedia.org/wiki/Observable_universe)

If the universe is 13.7 billion years old, how is the diameter 93 billion light years? Light travels 1 light year for every year. Then if two particles were expanding outwards to form the size of the diameter, it would be approximately 28 billion light years. Can somebody explain this confusion?

 

[Dmitry67]

From the same article:
http://en.wikipedia.org/wiki/Observable_universe#Misconceptions

13.7 billion light-years. The age of the Universe is about 13.7 billion years. While it is commonly understood that nothing travels faster than light, it is a common misconception that the radius of the observable universe must therefore amount to only 13.7 billion light-years. This reasoning makes sense only if the Universe is the flat spacetime of special relativity; in the real Universe, spacetime is highly curved on cosmological scales, which means that 3-space (which is roughly flat) is expanding, as evidenced by Hubble's law. Distances obtained as the speed of light multiplied by a cosmological time interval have no direct physical significance

 

[filegraphy]

The visible universe is thus a sphere with a diameter of about 28 billion parsecs (about 93 billion light-years). (http://en.wikipedia.org/wiki/Observable_universe#Misconceptions)

Can you explain the calculation to this diameter.

 

[Chalnoth]

The visible universe is thus a sphere with a diameter of about 28 billion parsecs (about 93 billion light-years). (http://en.wikipedia.org/wiki/Observable_universe#Misconceptions)

Can you explain the calculation to this diameter.

Basically, the CMB which we see today was emitted from matter that was, at the time, about 44 million light years away. At the time, however, the universe was expanding very rapidly, so that the light has taken a full 13.7 billion light years to get here. In fact, for much of this time it wasn't even approaching us, but the rapid expansion left photons traveling in our direction even more space to travel than they crossed. Eventually the expansion rate slowed enough that the photon started to make headway, and finally arrive after 13.7 billion years.

In that time, our universe expanded by a factor of about 1100 times. This means that the matter which emitted the CMB we see today at 44 million light years away is currently around 48 billion light years away. But this distance has little to do with the path light traveled to get here.

 

[sardar]

I can explain this confusion by first clarifying that the observable universe – the portion of the universe that we can see – is estimated to have a diameter of 93 billion light years, not the entire universe. This is because the universe has been expanding since the Big Bang, and the light from the most distant objects we can observe has been traveling towards us for 13.7 billion years. This means that the light we see from those objects has traveled a distance of 13.7 billion light years to reach us.

However, during that time, the universe has continued to expand, causing those objects to move further away from us. This is similar to how the space between two objects on a rubber band will stretch as the band is pulled apart. This expansion has caused the light from those objects to travel an additional distance, making the total distance the light has traveled to reach us 93 billion light years.

It is also important to note that the universe is not a static object with a defined diameter. It is constantly expanding, and the 93 billion light year measurement is just an estimate based on our current understanding and observations. As we continue to study and learn more about the universe, our understanding of its size and age may change.