The 1st stars in the universe formed earlier than thought

[dfjchem721]

Here is another example on how BB observations can vary considerably, and these from real cosmologists using HST. I always assume, for good reason, that people given viewing time on HST, or any other major astronomical instrument were granted this time because they had good reasons. Below is a repost of one of my "discoveries" found when looking for unique ideas on BB cosmology:

Had to find a reference to that red giant data*. Actually they used the HST to observe the "helium flash" from distant red giants and used their light intensities to develop a measuring stick to more and more distant flashes in more distant galaxies and came up with red-shift values for various galaxies containing these red giants. From this data the Hubble Constant has a slightly different value than they have found using Cepheid variables.

This work is purely an optical evaluation of the age of the universe, and not based on the CMBR, the evaluation of which seems to be an on-going process (new wrinkles, dents, and new wiggle room?)!

Certainly worth a read (from 2019):

* https://news.uchicago.edu/story/new...t-adds-mystery-about-universes-expansion-rate

quoting from the end of the above article:

“We are working at the frontier of what is currently known about cosmology,” Freedman concluded. “These results suggest that we do not have the final answer yet. The burden of proof is high when claims of new physics hang in the balance, but that’s what makes it exciting,” she said. “Either way the conflict resolves, it is important. We either confirm our standard model of cosmology, or we learn something new about the universe.”

(But they are from the University of Chicago, so what do they know?!)

 

[rod]

Torbjorn Larsson commented, "So is Pop III stars, which have a lot of problems such as how they would be formed. Don't be surprised if such objects turn out to be direct collapse objects that doesn't conform to our idea of a star."

FYI, this is currently where Population III star modeling is at. Star Formation Under Cosmological Conditions Population III stars do not form like Population I or II stars, e.g. M42 gas in Orion. The attached report states:

"The Pop II stars found in globular clusters cannot be the first stars to have been formed after big bang, because these first stars were mainly H/He stars and can be termed "zero-metal stars". Thus, pop III stars would have been formed in gas clouds composed mainly of H/He. Such clouds have higher pressure than the metal-rich clouds of the same temperature. This may already indicate formation of high-mass stars of several hundred solar masses [9]. Despite of great effort, the discovery of pop III stars remains elusive...(a) The small perturbation of the uniform cosmological background can be adopted provided the so called ΛCDM model remained valid on small scale (see basics of this model are presented below). (b) Absence of heavy elements leaves the atomic and molecular hydrogen as main agent of radiative cooling and source of opacity. (c) The intergalactic medium had no source of turbulent motion before supernova explosions (d) The magnetic field might be less efficient, but still not is not sufficiently explored, Despite these arguments, it remains challenging to consider processes occurring from cosmological scale to proto-stellar scale...The primordial star formation is unique, since it is related to CDM model of cosmology. This seems to have happened in a minihalo of about 10^6Msun at redshifts z=20-30 ([3]). The JamesWebb Space telescope (JWST) will give information about the abundances of the most metal-poor stars, which will constrain the nucleosynthesis from the first supernovae."

Population III star formation process exist in computer simulation - not observation like ALMA or SPHERE looking at stars and dust clouds or observations of M42 in Orion. If Population III stars never existed, that is another issue discussed in this thread.

 

[Helio]

Just for an example, there is no hard evidence that population III stars ever existed. They are purely hypothetical.

One of the things that has helped me a lot as an amateur is to get my head around how scientists categorize ideas, suppositions, conjectures, hypotheses and theories. There is some hierarchy to them, but the separation of that which is subjective from the objective elements (required for any science) helps us understand how serious to hold them.

Direct observations aren't a do or die requirement for science. If so, then how could we take the black hole ideas seriously. We can infer their existence from the observations we have, including, for instance, x-ray radiation due to their ability to heat accretion disks falling into them.

Suppositions are almost to be taken on a subjective basis where the evidence doesn't yet warrant a clean hypothesis. Suppositions, however, are important to start the process.

Pop III stars provide the gap between the objective evidence of, say, the CMBR and the stars and galaxies at the limits of our observational abilities (Pop II stars). IIRC, the spectrum of those most distant galaxies show less metals than those much closer. This is would be a requirement of the BBT where only hydrogen and helium (ignoring tiny li and Be amounts) had time during the expansion to fuse together.

The problem had been that it was difficult for limited computer programing to allow massive stars to form with just H & He, but that has changed and it will only get better, no doubt. I think it is now the mainstream view that the modeling is respectable enough to take us from supposition to a solid hypothesis that they are there, and partly because better telescopes will allow us to falsify the claims.

But they do play a role in a lot of BB models. Some accept them as fact, and that anyone questioning them is ill-informed.

I suppose that's not an unreasonable statement but facts, to be a bit pedantic if I may, are the measurable observations. The weight that BBT has today and its requirement for Pop III stars, along with advance computer modeling make them worth betting your cat on them. [I don't have a cat but I would bet one if I did. ]

Some will say that facts are not dictated. To be sure, facts are demonstrated. And no one has demonstrated population III stars existence, much less beyond doubt.

Again, astronomy does allow indirect evidence and strong hypotheses to come from them. Once they are observed, hopefully, then it will confirm the hypothesis and add yet further support for the BBT as another prediction comes to fruition.

 

[Helio]

Well, "white hot" is technically black body radiation as all other hot objects including colored stars, it is a very pity description.

I'm unclear what you are saying here. The topic of bb radiation and why things look white would be a fun thread. Stars, except the cooler ones due to their molecular atmospheres, come surprisingly close to a bb model.

So is Pop III stars, which have a lot of problems such as how they would be formed. Don't be surprised if such objects turn out to be direct collapse objects that doesn't conform to our idea of a star.

What do you mean by a "direct collapse object"? What do you see that explains the origins of metals?

 

[dfjchem721]

Direct observations aren't a do or die requirement for science.

As a biochemist, I am well aware of the need for drawing inferences from data that are not direct. About the only time we get to "see" what we are doing is in gel electrophoresis, where stained bands of protein or DNA can be seen with the naked eye. All the rest is conjecture, but it is based on an overwhelming amount of data to support it.

Such data does not yet exist in the field of cosmology. If it did, all those people "in the know" would not be hotly debating each other about so much of it, re-evaluating the CMBR, using HST to find alternate Hubble constants, etc. etc., jeez, the list of "not-so-sure" ideas is rather significant.

That there is so much back-and-forth among the experts in the field is all the evidence most rationale people would need to decide the story is far from over, much less 100% certain!

 

[Helio]

As a biochemist, I am well aware of the need for drawing inferences from data that are not direct. About the only time we get to "see" what we are doing is in gel electrophoresis, where stained bands of protein or DNA can be seen with the naked eye. All the rest is conjecture, but it is based on an overwhelming amount of data to support it.

Nice! I know next to nothing of biology or biochemistry, so I look forward to what you have to say about it in future threads. [Recently, learning how fragment RNA can falsely indicate infectiousness suddenly became important to me during this pandemic. ]

Such data does not yet exist in the field of cosmology. If it did, all those people "in the know" would not be hotly debating each other about so much of it, re-evaluating the CMBR, using HST to find alternate Hubble constants, etc. etc., jeez, the list of "not-so-sure" ideas is rather significant.

Since there are many parameters involved, and each needing tweaks, the debates are inevitable and healthy, no doubt. To your point, New Wright's cosmology calculator requires the users own values be entered.

The margin of error for the age of the universe was great enough to allow the 13.7 Byr value to get tweaked to 13.8 Byrs. It seems unlikely this will become something far greater or less, though BBT is so vast that many new things certainly can emerge as observations become better and farther. The mainstream views, at least, should be on solid ground, or do you suggest little should be seen as mainstream?

That there is so much back-and-forth among the experts in the field is all the evidence most rationale people would need to decide the story is far from over, much less 100% certain!

Agreed, but I think we may argue how "far" we are from the target values. Better data, especially hi Z objects, will tweak things, but it seems reasonable to assume that little will be turned upside down. Dark Energy, might be a fair exception.

 

[dfjchem721]

Nice! I know next to nothing of biology or biochemistry, so I look forward to what you have to say about it in future threads. [Recently, learning how fragment RNA can falsely indicate infectiousness suddenly became important to me during this pandemic. ]

Sorry folks, brief off-topic that most should appreciate.

Prior to the current form, there were 3-4 coronaviruses causing "common" colds in the U.S. These coronaviruses are all sense, single-strand RNA viruses, aka retroviruses. The fragment issue is due to related sequences among all coronaviruses. If you are looking at fragmented and related sequences, you might get a false positive for the current nasty one (SARS-CoV-2). So if you had another coronavirus that causes "colds", since it will have the same sequence in certain regions, will give a false positive.

The same is true for antibody testing. All of these assays must become very accurate or we will not know for sure what is going on. Sorta like the BB. At least we can both agree that there is not a firm consensus for that "theory", or is it "theories"?

 

[Helio]

Sorry folks, brief off-topic that most should appreciate.

Prior to the current form, there were 3-4 coronaviruses causing "common" colds in the U.S. These coronaviruses are all sense, single-strand RNA viruses, aka retroviruses. The fragment issue is due to related sequences among all coronaviruses. If you are looking at fragmented and related sequences, you might get a false positive for the current nasty one (SARS-CoV-2). So if you had another coronavirus that causes "colds", since it will have the same sequence in certain regions, will give a false positive.

The same is true for antibody testing. All of these assays must become very accurate or we will not know for sure what is going on. Sorta like the BB. At least we can both agree that there is not a firm consensus for that "theory", or is it "theories"?

Thanks for your comments on this tough subject!

I will just make one post on this because it is important information about something that affects space -- sort of a stretch but the pandemic just cause delay to the JWST. I'm not sure the moderators would even want a thread on this sensitive subject, though I hope the may tell us to start one.

Here is my understanding that I would like corrected if in error, which is likely. The antibodies, once developed, deteriorate the virus. SARS-CoV-2 has some sort of outer layer(?) that allows it to sneak(?) into a healthy cell. Once this outer layer is ruined by the antibodies, the virion is rendered unharmful. With some time, the RNA will fragment, but the tests we have that determine if one "has the virus" looks for the RNA. If found, the test can't distinguish whether or not this RNA is of an active (contagious) virion or not. Am I close? [My wife is diabetic, Type A, older, overweight, etc. so my interest isn't just academic.]

 

[dfjchem721]

Here is my understanding that I would like corrected if in error, which is likely. The antibodies, once developed, deteriorate the virus. SARS-CoV-2 has some sort of outer layer(?) that allows it to sneak(?) into a healthy cell. Once this outer layer is ruined by the antibodies, the virion is rendered unharmful. With some time, the RNA will fragment, but the tests we have that determine if one "has the virus" looks for the RNA. If found, the test can't distinguish whether or not this RNA is of an active (contagious) virion or not. Am I close? [My wife is diabetic, Type A, older, overweight, etc. so my interest isn't just academic.]

This is more complex, will boil it down. Abs do not destroy the virus, they only bind to it. Abs have variable affinities - binding strength. You need high affinity to neutralize the virus. This is critical, as lower affinity Ab can actually make it worse. This is the most difficult aspect of the vaccine, getting high affinity antibodies that bind virions and cross link them with other Abs, all binding virions, creating a large matrix that is then eaten by other white blood cells, and destroyed. That is largely how the virus is cleared by Abs.

The outer layer is the "envelope", and in this case, membrane and protein, the most complex of all virus outer coats. Destroy the membrane, destroy the virus. This membrane is much like our cell membranes, so when it attaches to cells, the membranes fuse and its RNA gets inside, and starts to replicate. That is what all the sanitizers are about. Fortunately, this virus is easily inactivated by standard things (not H2O2 though!!) like soap, etc. Note that 70% IPA destroys it within seconds. RNA is pretty unstable, so the virus RNA genome will fragment once the envelope is destroyed, and that is where false positives can creep into a poorly discriminating assay.

 

[rod]

FYI. BBN is a delicate balance in creating the primordial elements of H, He, and a bit of Li. The neutron lifetime is critical in BBN, Scientists carry out first space-based measurement of neutron lifetime Other reports, Big Bang Nucleosynthesis: Predictions and Uncertainties, Big Bang Nucleosynthesis constraints and light element abundance estimates

Getting the correct abundance of H, He, and perhaps a bit of Li, is important for Population III stars too, Pop III still remain to be validated or confirmed. Adjustments to neutron lifetime can change H, He abundances too during BBN.

 

[Helio]

This is more complex, will boil it down. Abs do not destroy the virus, they only bind to it. Abs have variable affinities - binding strength. You need high affinity to neutralize the virus. This is critical, as lower affinity Ab can actually make it worse. This is the most difficult aspect of the vaccine, getting high affinity antibodies that bind virions and cross link them with other Abs, all binding virions, creating a large matrix that is then eaten by other white blood cells, and destroyed. That is largely how the virus is cleared by Abs.

The outer layer is the "envelope", and in this case, membrane and protein, the most complex of all virus outer coats. Destroy the membrane, destroy the virus. This membrane is much like our cell membranes, so when it attaches to cells, the membranes fuse and its RNA gets inside, and starts to replicate. That is what all the sanitizers are about. Fortunately, this virus is easily inactivated by standard things (not H2O2 though!!) like soap, etc. Note that 70% IPA destroys it within seconds. RNA is pretty unstable, so the virus RNA genome will fragment once the envelope is destroyed, and that is where false positives can creep into a poorly discriminating assay.

Thanks for sharing that knowledge!

 

[Grthinker]

Did the models claim 400 million years was too early for formation?

Yes, that's very likely, but future observations (e.g. JWST) will improve the unwanted degrees of wiggle. Part of the problem is trying to understand how having only hydrogen and a little helium would form a star, how big they could be, etc. These stars don't exist even in the old globular clusters.

I suspect all is in order, but we still need observations to help build better models.

Eternity is a long time! I'm sure happy that as a species we seem to want to explore and find these items from the past, but reach the 'fence': I doubt ti.