Recent content by Skolon

This thread is very appropriate with what I intend to ask (at least for the first two questions), so please allow me to do it even it is an old thread. From this forum I learned that the CMB radiation we receive today was emitted by primordial plasma when it was at 41 million ly away from our...

Thank you for your patience, Chalnoth.

What I intend to say is that redshift, for me, explain what happened with the light along its way not with its source after the light was emitted. This is way I don't understand how we can tie a phenomenon that manifests on light with the evolution of its emitter. Especially when the emitter is...

?? :smile: The first word must be "expansion factor", right? If I remember right z can be defined as: z = \frac{\lambda _o}{\lambda _e} - 1 where λo, λe are the observed and emitted wavelengths respectively So, if z is zero then λo = λe. We can conclude the source of light it is not...

This confuse me a little. I thought we measure the redshift of a distant light and find how far is the source of it. If practically we do like just I said (i.e. we measure the redshift not the expansion factor), why we use the above definition?

For me this is a clear example of how mathematics dominates today physics sciences. It is fair to stop try to provide a physical explanation of the notion of time just because in the mathematical theory that best explains today the reality of the Universe, time has almost no special meaning? I...

Sorry for asking you, but you read what Marcus explain above?

I hope I'm not wrong, but from what I remember H has a logarithmic growth to a limit value. That mean "Big Rip" Theory has been disproven.

Thank you Chalnoth, it is exactly as I thought.

I heard this explanation many times but I never understood if there is actual evidence for it or is just an inference. Perhaps it is just our inability to measure the expansion (if it exists) over short distances.

I found something amusing. :smile: If I use on Cosmos Calculator H=70.4, Omega=0.2726 and Lambda=0.7274 on Mozilla (version 3.6.22) I must put z=1.13 to obtain "Speed away from us now" = speed of light. Instead, on IE (v. 6.0) with same parameters I must use z=1.42 for the same result. I think...

Marcus, can you explain me more about The Cosmos Calculator? When I look to this http://en.wikipedia.org/wiki/Lambda-CDM_model#Parameters", I don't know what to put on Omega and Lambda. I use 73.8 Km/sec/Mpc for H and I try to find z for that galaxy that have a "speed away from us now"...

Wow, this is a little strange because that mean that when we say "a galaxy that is a billion light years away" we are not talking about a distance but about a period. :confused:

Expressing the cosmological distances with conventional terms is very confusing. For instance, if we say that "a galaxy is a 1 billion light years away" what this is really mean? 1. If all moves stopped (moves in space and expansion) the light will travel from that galaxy (center of it) and us...

Yes, it is, but just mathematically. You make a wrong physical assumption: "just need to know the full wavefunction of the universe at anyone point in time". This is a physical impossibility, I'm sorry. So, for us the Universe will be forever non-deterministically.