37 replies to this topic

[Starman1]

See:

https://www.scientif...3WSXC3Rw.WEer5A

It turns out that only 9% of detectable matter is in stars and galaxies.

[Andrew_L]

Have they found my missing reading glasses  amongst that lot? 

[TOMDEY]

It's certainly a "refreshingly simple" explanation. Anytime I read about the ~missing dark matter~ and the leap to exotics --- I have always wondered whether it might just be diffuse "regular stuff" that we are looking right through. They (this team) seem to be leaning very heavily (conclusively?) toward the "regular stuff" for the lion's share of what was previously considered to be missing. So much so that it could entirely eliminate the exotics from the list of things that somehow must exist. I'm sure they will be debating this for quite some time.

 

Analogy: The Luminiferous Ether --- ultimately, thankfully, debunked as unnecessary.

Analogy: Otherworldly UOFO's~ where professionals and amateurs alike jump to the conclusion that they must be hyperadvanced sentient aliens buzzing us with gymnastic time-warped levitating vehicles (rather than misinterpreted human technologies, misuse of equipment, illusion, and wishful thinking).

 

No need for exotics should console and refresh us --- the Universe more understandable.     Tom

[maniack]

Have they found my missing reading glasses  amongst that lot? 

Or socks?

[deSitter]

See:

https://www.scientif...3WSXC3Rw.WEer5A

It turns out that only 9% of detectable matter is in stars and galaxies.

 

Sigh. A bit premature.

 

I would point out, that those who argue for the essential importance of cosmic magnetic fields, the sort that create vast filamentary structures in intergalactic space, have been regarded as heretics and denied telescope time. See: Hannes Alfven.

 

--drl

Edited by deSitter, 18 June 2025 - 04:33 PM.

[Shorty Barlow]

If a 24mm ES 68 degree in a bolt tube turns up, it's mine.

[KTAZ]

Refreshing to see Occum take back control...

[ButterFly]

It's certainly a "refreshingly simple" explanation. Anytime I read about the ~missing dark matter~ and the leap to exotics --- I have always wondered whether it might just be diffuse "regular stuff" that we are looking right through. They (this team) seem to be leaning very heavily (conclusively?) toward the "regular stuff" for the lion's share of what was previously considered to be missing. So much so that it could entirely eliminate the exotics from the list of things that somehow must exist. I'm sure they will be debating this for quite some time.

 

Analogy: The Luminiferous Ether --- ultimately, thankfully, debunked as unnecessary.

Analogy: Otherworldly UOFO's~ where professionals and amateurs alike jump to the conclusion that they must be hyperadvanced sentient aliens buzzing us with gymnastic time-warped levitating vehicles (rather than misinterpreted human technologies, misuse of equipment, illusion, and wishful thinking).

 

No need for exotics should console and refresh us --- the Universe more understandable.     Tom

This is NOT missing dark matter.  This is missing ordinary matter that was previously unaccounted for by summing up the luminosity derived mass of ordinary matter.

 

This present observation is a follow up to: Half the universe’s ordinary matter was missing — and may have been found

[slavicek]

It's certainly a "refreshingly simple" explanation. Anytime I read about the ~missing dark matter~ and the leap to exotics --- I have always wondered whether it might just be diffuse "regular stuff" that we are looking right through. They (this team) seem to be leaning very heavily (conclusively?) toward the "regular stuff" for the lion's share of what was previously considered to be missing. So much so that it could entirely eliminate the exotics from the list of things that somehow must exist. I'm sure they will be debating this for quite some time.

 

Analogy: The Luminiferous Ether --- ultimately, thankfully, debunked as unnecessary.

Analogy: Otherworldly UOFO's~ where professionals and amateurs alike jump to the conclusion that they must be hyperadvanced sentient aliens buzzing us with gymnastic time-warped levitating vehicles (rather than misinterpreted human technologies, misuse of equipment, illusion, and wishful thinking).

 

No need for exotics should console and refresh us --- the Universe more understandable.     Tom

And do not forget the search for that planet Vulcan! It's "need" has been eliminated by new theory (the theory of relativity, that is)

[ButterFly]

Sigh. A bit premature.

 

I would point out, that those who argue for the essential importance of cosmic magnetic fields, the sort that create vast filamentary structures in intergalactic space, have been regarded as heretics and denied telescope time. See: Hannes Alfven.

 

--drl

You have to love how a mere five years goes from that previous title, to the first line of the present article:

 

 

Half of the universe's ordinary matter was missing — until now.

 

You also have to love how people can just gloss over "ordinary" to fit their perverse desired to go back to the "simple times".  Pepperidge Farm Remembers!!!

[TOMDEY]

This is NOT missing dark matter.  This is missing ordinary matter that was previously unaccounted for by summing up the luminosity derived mass of ordinary matter.

This present observation is a follow up to: Half the universe’s ordinary matter was missing — and may have been found

Well... that's extraordinary!    Tom

[TOMDEY]

And do not forget the search for that planet Vulcan! It's "need" has been eliminated by new theory (the theory of relativity, that is)

Yep! The "inexplicable" precession of Mercury's orbit was actually discovered a heck of a long time ago. Little did they realize that they had ~relativity~ staring them right in the face! Similarity: One of my teachers (Dr. Givens --- also a beekeeper) physical optics --- he told this personal anecdote regarding experimental results and observations. Some readings he got were counter to whatever theory was then popular... so he tossed out those outlier readings. A few years later, someone else used similar data to land the Nobel Prize! Given's suggestion is that we most especially focus on outlier data, rather than waive it off.    Tom

[ButterFly]

Some readings he got were counter to whatever theory was then popular... so he tossed out those outlier readings.  A few years later, someone else used similar data to land the Nobel Prize! Given's suggestion is that we most especially focus on outlier data, rather than waive it off.

So that Nobel laureate faked the data just like that other liar and got a Nobel Prize for it?  Don't you just love the ambiguity in language.

 

But yes, indeed, this matter isn't extraordinary at all.  If's the same run of the mill 5% of the ordinary matter energy content of the universe the Standard Model explains so well.  And sure, 5% is of course good enough to start arrogating a "Theory of Everything" based on strings - just like when you ignore those data above.  They don't need to know it's 95% garbage, once they haul it away.  I smell a Nobel Prize coming!  It must be chocolate wrapped in golden foil.

 

On a more serious note, this does go a long way to explain some odd things.  Globs don't develop later in a galaxy's evolution, so far as we know, for spiral galaxies.  They do, however, for ellipticals.  It has been suspected that there is some source of (ordinary) matter feeding into galaxies to help them continue to grow, long after they are "old".  Having found this source of (ordinary) matter to feed is a really good start.  But sure, all that dark matter is helping to feed in as well.

 

On a lighter note, cosmological presumptions don't need super duper modification.  That's always a good thing.  Each of the three standard cosmological assumptions has quite a bit of data challenging it.  With respect to the "uniform density" presumption, it has been fairly clear for a while that galaxy clusters are arranged along threads as filaments.  What wasn't clear was whether those "voids" were devoid of matter.  These data help show that wet sponge is indeed a better model, rather than a dry sponge, or just a pool of water.  That's rather much a relief.

 

Despite what Dr. GivenInTheGarbage may think, every bit of data helps update priors.  It's best to check whether it is garbage, rather than assuming it to be so, and tossing away a perfectly good chocolate coin wrapped in golden foil.

[csrlice12]

I like chocolate.

[Shorty Barlow]

I like chocolate.

Man I'm getting the munchies just reading this thread.

[Andrew_L]

I take it that this discovery has no material effect on the assumed role dark matter plays. 
 

No pun intended. 

[Starman1]

I took it to mean the role of dark matter just got a lot smaller.

[12BH7]

Not being a Cosmologist but having taken courses that dealt with theoretical math, there's a lot of "let's assume" going on. What that means is we'll take a term and assume it's this, just to make the equations fit with the other thousand equations. Sort of like a gigantic game of Jenga.

 

Some of these problems are in reality worked backwards. Meaning I want an answer, so this value must be "this".  Again, I'm no Cosmologist, but in the end the missing dark matter might end up being a set of missing equations.

 

I'm talking nonsense, but that's how higher math works.  Remember string theory?

[ButterFly]

I took it to mean the role of dark matter just got a lot smaller.

Not at all.  This ordinary matter was already included in ordinary cosmology, it's just that no one knew where it was.  There is no new "amount" of ordinary matter, just a location.  Seeing into the void is quite hard.

[Dino]

...

 

I'm talking nonsense, ...

I fully agree.

[TOMDEY]

I took it to mean the role of dark matter just got a lot smaller.

Yes! --- quite possibly zero. It finally dawned on me that what was missing from our bean-counting is mass --- not dark, light, grey, "regular" or exotic --- just mass. So this interesting mechanism for detecting and mapping more traditional stuff to approach topping-off the mass deficiency --- proportionally reduces our fixation on imagining we need irregular massive species.

 

Analogy #1 > Concluding that "inactive" black holes don't exist just because they are are not revealing themselves by gobbling up more matter.

Analogy #2 > Deciding that earth-mass exoplanets are profoundly rare just because they are currently profoundly difficult to detect.

 

There does still seem to be some evidence for some exotic dark matter as candidate --- but diminished amount and diminished interest.

PS: Note what matter is --- just a reading on a meter... which we humans declare to therefore be ~real~ only because we noticed the meter click.    Tom 

[Olimad]

All this "dark stuff" feels like the universe’s version of a Ponzi scheme: the deeper we look, the more exotic ingredients we have to invent just to keep the model afloat!

 

Our era will probably go down in history as the "Dark Age" of cosmology, and not because of all the needed dark stuff…

 

Now, back to the search for WIMPs, axions, and the like, complete with generous funding and a healthy waste of time and brainpower.

 

Edit: Le Verrier, if you could see us now, I’m sure the scientific community would be saluting you.

Edited by Olimad, 19 June 2025 - 05:24 PM.

[12BH7]

I fully agree.

I surely do not have an argument to defend myself. But I have had courses diving deep into theoretical equations. 

[ButterFly]

Yes! --- quite possibly zero. It finally dawned on me that what was missing from our bean-counting is mass --- not dark, light, grey, "regular" or exotic --- just mass. So this interesting mechanism for detecting and mapping more traditional stuff to approach topping-off the mass deficiency --- proportionally reduces our fixation on imagining we need irregular massive species.

 

Analogy #1 > Concluding that "inactive" black holes don't exist just because they are are not revealing themselves by gobbling up more matter.

Analogy #2 > Deciding that earth-mass exoplanets are profoundly rare just because they are currently profoundly difficult to detect.

 

There does still seem to be some evidence for some exotic dark matter as candidate --- but diminished amount and diminished interest.

PS: Note what matter is --- just a reading on a meter... which we humans declare to therefore be ~real~ only because we noticed the meter click.    Tom 

Double edged sword here though.  So, with these measurements, one can detect that whole lot of ordinary matter in these voids.  Again, no additional ordinary matter, just previously unaccounted for.  However, these measurements rely of fast radio burst illuminating this previously unaccounted for ordinary matter.  That rather begs the question: if there is all this ordinary matter out in these voids, how much dark matter is out there as well, and how would we measure it?

[starcanoe]

My very limited understanding is that some form of dark matter is needed to explain galaxy rotational rates. The existence of dark matter also solves some other cosmological problems/observations. This detection of previously unseen/undetected regular matter way out in the voids between galaxies and even voidier the voids between galaxy clusters doesn't help with the dark matter "needed" to explain galaxy rotation.

I recently saw another random internet reference to a theory of "dark" hydrogen...it isn't dark matter but it is hydrogen in some special quantum state that basically renders it unreactive to light. And I suppose if it also didn't allow the hydrogen to interact with itself or other matter that work..

https://researchoutr...to-dark-matter/

Edited by starcanoe, 20 June 2025 - 08:15 AM.