The Universe is Pretty Big

Psiolent writes "According to a recent article on Space.com, the universe is pretty big (156 billion light years across, to be more precise). Some recent research examining 'primordial radiation imprinted on the cosmos' has led to this conclusion, as well as a few others. This finding is particularly interesting considering the universe is only 13.7 billion years old (which would mean the universe has been expanding faster than light travels), but the article does a good job addressing this seeming paradox."

Comments

Re:since light is the FASTEST moving thing

[muon1183]

Um, not quite. If you had RTA, you would understand that the reason the radius of the universe is so large (relative to it's age) is the hubble expansion of the universe. According to current theory, the universe has been expanding since the big bag at an increasing rate. This expansion is not governed by special relativity, and a result of this expansion is that if something travelled 1 light-year in the early universe, it has now travelled something on the order of 1000 light-years. And yes, IAATP (I am a theoretical physicist (in training, at least))

Re:Universe potentially older

[drudd]

As the previous answer noted, you're a little confused about the Carbon-Nitrogen-Oxygen (CNO) cycle. In these set of reactions, the carbon is only used as a catalyst for making helium (so you're still turning H -> He, but you're doing it by repeatedly capturing protons (H) and then beta-decaying). See this article for more information on CNO.

Now the argument that the referenced article is using is that less massive stars will stay on the main sequence longer, due to the reduction in CNO efficiency. Thus older globular clusters will have a bluer turnoff than previously expected.

While this will cause a systematic underestimation of the age of globulars by ~0.7-1.0 Gyr, the uncertainties are so large (+/- 1-1.5 Gyr or so), that they are still consistent with the age of the universe derived from CMB observations.

Doug

Only space expanding?

[DerWulf]

I am no scientist, so please forgive. How come the distances between objects seem to be increasing ( space time expansion or so they say) but not their size? What makes matter so special that the space time between molecules is not expanding as well? What makes our perception so special that only the distances between objects we like to observe ( galaxies, stars) increases but not the distances within them?