I thought Sabine Hossenfelder’s newest video was interesting. Also interested in any of your thoughts on it…
From the video transcript:
These recent developments make me think that in the next ten years or so, we will see a major paradigm shift in cosmology, where the current standard model will be replaced with another one. Just what the new model will be, and if it will still have dark energy, I don’t know.
The “standard model” (sometimes called the “concordance” model) of cosmology posits that:
General relativity is the correct theory of gravity
There exist stuff that interacts purely (or almost purely) gravitationally called dark matter
Further, these dark matter is cold, i.e., it does not move quickly (to understand this nomenclature you can think of hot air, for example, possessing particles that move faster than cold air)
There exist stuff that interacts gravitationally to accelerate the expansion of the universe, this stuff is called dark energy
Further, the amount of this dark energy is the same everywhere, i.e., a constant; this leads to the dark energy in this model being called a cosmological constant (the value of this constant is often written as the Greek letter lambda, Λ)
Finally, there is all the usual matter and fields that we are used to (e.g., atoms, photons, etc)
Combining the stuff I wrote in bold leads to the official name for the “standard model” of cosmology, which is the ΛCDM-model (Λ for the cosmological constant dark energy and CDM being the abbreviation of “cold dark matter”).
Inflation is not technically part of this model, but an extension of it.
Edit: Whoops, of course I forgot the assumption of the ΛCDM-model that is most germane in this thread:
The universe is, at large scales, the same everywhere (spatially homogenous) and the same in every direction (spatially isotropic)
Yes, and we expect them to contribute to the growth of supermassive black holes at the center of galaxies. There is even the possibility that the first supermassive black holes were formed by dark matter that collapses upon itself.
This is challenging, as it is difficult to measure the amount of dark matter (and its evolution over cosmic timescales) around a blackhole.
Thanks for raising this interesting topic, Valerie. I hope you and the little one are doing well!
The failings of the Newtonian model gradually became apparent in the late 19th and early 20th centuries. The stage was set for Einstein’s general relativity, with which everyone in this thread is at least familiar, I’m sure.
Before general relativity was even introduced, however, the age of the universe was known to be at least tens of thousands of years old. In 1676, hundreds of years before Einstein, Ole Christensen Romer estimated the speed of light with an error of only about 20%. In 1729, James Bradley estimated the speed of light with an error of only 1.5%.
Given the speed of light and the distance that light has traveled, you can calculate when the light was emitted from its source. Well before the advent of general relativity, astronomers knew that the Milky Way has a span of at least 10s of thousands of light-years. This observation set a lower bound on the age of the universe at 10s of thousands of years.
Today, we have much better instruments and a much more accurate understanding of light travel in the universe. The Hubble is viewing electromagnetic radiation today that began its journey billions of years ago.
In the late 19th century, geophysicist John Perry estimated the age of the earth at 2 to 3 billion years based on heat dissipation equations. This sets a much larger lower bound on the age of the earth.
The next big cosmological theory will be fascinating, whatever it may be. It would be quite mistaken, in my opinion, to think that somehow the new theory will shrink the age of the universe from billions of years to mere thousands. The evidence for billions of years is overwhelmingly strong.
Hope this was helpful. Keep loving your little one!
Thanks, but my interest I science is wider than the age of things. I am curious how much others agree with Sabine on this based on the papers she cited.
After learning some about cosmology, I definitely thought it seemed poised to have some kind of fundamental change in the model. Whatever the change is it does seem like it what would have an effect on time in some way, even if it isn’t significant.
Anyway, I’m sure it would be an understatement to say that the vast majority of physicists would never consider a model without long ages given evolutionary models in other areas of science. If there was no widely accepted cosmological model, maybe some biologists would consider an alternative to the current understanding, and if the evolutionary model is overturned, maybe some cosmologists would consider an alternative. But otherwise I don’t expect anything to change soon. Even those kinds of changes would probably take decades.
Well…unless we soon get telescopes that are strong enough to consistently see objects farther back than the supposed age of the universe.
It seems to me that would just force cosmologists to think the universe is even older than they already do. I can’t wait, however, for the launch and operation of the James Webb Space Telescope and the European Extremely Large Telescopes. We live in exciting times.
Is there anything in Valerie’s opening post to suggest that she was drawing that inference from Sabine Hossenfelder? If so, I didn’t see it. And certainly I’ve seen nothing in Hossenfelder’s writing that suggests she believes in a universe only thousands of years old.
It’s an almost universally held belief among YECs that just because scientists don’t know everything about the history of the universe, that somehow means that they don’t know anything about the history of the universe, and that everything under the banner of “historical science” is therefore fair game for denial. It’s a fallacy that crops up so often in discussions with YECs that whenever they bring up any unknown or uncertainty in mainstream science, there’s a tendency to automatically assume that this is another example of it.
There is the possibility that Valerie is not trying to make that point, of course, and that we’re jumping to that conclusion erroneously. But if that’s the case, since she identifies as a YEC, she needs to make that clear because it would make her very much the exception rather than the rule.
I inferred that Chris had made this assumption; otherwise, why would he launch into defense mode regarding the age of the earth, when she hadn’t even mentioned it?
Yes, and that’s why it’s better to ask someone what point they are trying to make, instead of imputing an argument to them that they haven’t actually made.
That’s an unreasonable conversational requirement. She made a point about differences among experts regarding the standard model of cosmology. She drew no conclusion about the age of the earth in relation to that point. She said nothing about the age of the earth at all. She asked for comments only on the state of modern cosmological thought, not on the age of the earth. Why should she have to guard every statement she makes here, thinking: “These people here will probably assume I’m saying this for the purpose of defending YEC, so I’m obligated to clarify that I’m not?”
Conversation about origins is frequently poisoned by the fact that so often people don’t listen to what someone is saying but instead respond to what they imagine a person is probably secretly driving at. This site is called Peaceful Science, and one good way to keep things peaceful is not to assume someone is spoiling for a fight unless they say they are.
As I read it, Valery is inferring that who knows , maybe some cosmology will eventually shake out which does not require deep time. I would consider that to be an entirely hopeless prospect, but I appreciate that Valerie was careful not to overstate herself or to misrepresent Hossenfelder, and is digging into science from other sources than just YEC sites.
However, the age of the universe is inferred by astronomical observations which are quite independent of cosmology. The solar system was ancient under both the early conceptions of the steady state and big bang theories. Of the various lines of evidence of age, the most accessible to me are the hundreds of photos of interacting galaxies, such as the antennae galaxy. or the whirlpool galaxy, which by binoculars is just visible near the end of the handle of the big dipper. There are several more on the NASA site here. Under any cosmology, most of these collisions either played out over tens or hundreds of millions of years, or were created to exhibit a false history along the lines of the Omphalos hypothesis.