New research puts age of universe at 26.7 billion years, nearly twice as old as previously believed::Our universe could be twice as old as current estimates, according to a new study that challenges the dominant cosmological model and sheds new light on the so-called “impossible early galaxy problem.”
Are there any constants that we actually know to have varied along the lifetime of the universe?
I don’t know if this counts as a constant, but I read that time moved something like 5 times slower in the early years of the universe.
It didn’t as time is relative just like space. There is no absolute standard of time to say “time moves faster”. Faster relative to what?
Somewhat. Based on my understanding of current astronomy news (I’m not an astronomer, just interested in the field) it’s not proven, but it’s not entirely disproven either. For instance, my understanding is that the Hubble constant (rate of expansion of the universe) is different if measured with the Cosmic Microwave Background (newer universe) compared to measuring redshirt of stars (older universe). Of course, it could be that one of the measurements made an assumption that’s not true, but i don’t think it’s out of the question that the false assumption ends up being that the constant stays the same over time…
Take what I say with a grain of salt, though. Hopefully an actual astronomer can pitch in
According to my understanding, yes. For example, it is usually assumed that there was a period of time shortly after inflation when matter was in a quark-gluon plasma, which would imply a larger strong coupling than today, since a small strong coupling is associated to confinement. There was also the electroweak-epoch, during which the electromagnetic and weak interactions were unified, and the corresponding gauge bosons were massless. The masses of the W and Z bosons can thus also be regarded as time-varying, as well as the electron charge. However, it should be noted that these changes are not all that significant on the cosmological scales under investigation here (e.g. the quark epoch ended at about 10-6 seconds after the big bang, which is much much less than the age of the universe, and it’s assumed that it still took quite a while before the first stars formed). A time-varying cosmological constant could potentially be much more relevant (and some quantum gravity theories even predict it), and I’ve heard some people suggesting it as a potential solution for the H0 tension. However, I unfortunately can’t access the paper and assess what precisely the author did there, and whether it is in any way similar to what I just mentioned.