Sabine Hossenfelder is once again spot-on.
The brief summary is that the matter antimatter asymmetry is a pseudo-problem. It can be solved by using an initial value that agrees with observations, and that’s that. Of course it would be nice to have a deeper explanation for that initial value. But within the framework of the theories that we currently have, such an explanation is not possible. You always have to choose an initial state, and you do that just because it explains what we observe. If a physicist tries to tell you otherwise, ask them where they get their initial state from.
From the Backreaction blog.
3 comments:
Imagine if you applied this line of thinking to human evolution. Just start at an initial value that we're human, and we're done.
I think that the asymmetry problem is interesting... research in the field might lead to something else of value. I'm very dubious of value in researching dark matter, dark energy, Hawking radiation, string theory... but I'm not a physicist. I'm a BSEE/MSEE fwiw.
@Mrs. Watanabe
Imagine if you applied this line of thinking to human evolution. Just start at an initial value that we're human, and we're done.
That is not a good comparison. A better comparison would be the initial conditions of life on Earth. But even that is not a good enough comparison since the very early universe is unique and unlike anything else we know in the known history of the universe, also we know of nothing experimentally confirmed prior to it whereas we know well that life on Earth evolved from non-life and the universe had already existed for billions of years prior to the formation of Earth and life on Earth.
I'm very dubious of value in researching dark matter, dark energy, Hawking radiation, string theory... but I'm not a physicist. I'm a BSEE/MSEE fwiw.
It is highly likely that none of the conclusions of high energy physics, astronomy, or cosmology in the foreseeable future will have engineering applications, although advances in instrumentation and things like the statistics of cluster analysis in pursuit of these ends might.
Imagine if you applied this line of thinking to human evolution. Just start at an initial value that we're human, and we're done.
For many applications pinning down an approximate date of the emergence of the human species is all you need. But, when we have direct evidence from genetics and archaeology of archaic hominins, we can examine observationally based, laws of nature informed, hypotheses in a meaningful way.
In the conventional cosmology timeline for the universe, conditions where experimentally measured and confirmed aspects of the Standard Model of Particle Physics apply begin about one trillionth of a second (10^-12) after the Big Bang, and explaining everything but one trillionth of a second out of 13.8 billion years of the history of the observed universe is still pretty darned impressive.
But, in any field, there are some things that are probably intrinsically unknowable without some revolutionary new way of gaining information about them.
For example, in historical linguistics, it is probably impossible to know with any confidence what the languages in use 60,000 years ago look like.
Likewise, as we explore human prehistory, we will, almost by definition, never know the names or personal stories of the vast majority of people who ever lived even if they did things that were really important like bring humans across the Wallace line, or take humans out of Africa, or have a hybrid Neanderthal-human baby. We can construct plausible narratives that help bring what we do know alive (a la "Clan of the Cave Bear" which was in line with what science knew at the time), but that will never be more than historical fiction.
The issue with matter-antimatter asymmetry (and to a lesser extent, distinguishing between inflation theories and their alternatives) is that we have no way to confirm that the Standard Model of Particle Physics or General Relativity has a domain of applicability that continues to be valid in that first trillionth of a second, and have no way to directly, or even really, indirectly, observe conditions in that time frame. The best we can do is to work backwards to initial conditions at some time t=e where e is some very tiny fraction of a second. Further back in time than that, we are stuck with conjecture and guesswork.
So, in my view, our resources are better spent on problems that are not intrinsically unknowable.
Post a Comment