Scrutable

discovolante wrote: Sun Apr 20, 2025 11:05 am

dyqik wrote: Fri Apr 18, 2025 12:44 am

jimbob wrote: Thu Apr 17, 2025 8:07 pm
I can think of several ways that could be, but in what ways is it weak?

At the most fundamental level, it's a 3 sigma detection of DMS, when 5 sigma is the default for claiming a real detection.

Claiming that DMS must be a signature of life is very wrong. DMS has been detected in comets and the interstellar medium, and it definitely didn't come from life there.

Where does DMS in the interstellar medium and comets come from?

Gfamily wrote: Sun Apr 20, 2025 11:30 am

discovolante wrote: Sun Apr 20, 2025 11:05 am

dyqik wrote: Fri Apr 18, 2025 12:44 am

At the most fundamental level, it's a 3 sigma detection of DMS, when 5 sigma is the default for claiming a real detection.

Claiming that DMS must be a signature of life is very wrong. DMS has been detected in comets and the interstellar medium, and it definitely didn't come from life there.

Where does DMS in the interstellar medium and comets come from?

I think it's more that DMS would normally break down in planetary atmospheres, so its continuing presence is indicative of life processes. Similar to finding free molecular oxygen in an atmosphere, I guess.

IvanV wrote: Thu Jun 19, 2025 11:31 am Caltech claims it has located the "missing matter" in the universe. It is claiming that there is about three times as much baryonic matter (ie protons, neutrons, potentially other triquark particles, "ordinary" stuff we already know about) located in tenuous clouds in the intergalactic medium as there is located in galaxies.

If I understand this right, and Caltech is right, then this is a large part, or maybe even essentially all, of the "dark matter" we have been looking for. And it is ordinary baryonic matter, not made of some kind of particle we have not detected in our particle accelerators, as the string theorists would like. Nor is it stuff we know about but really hard to detect, like neutrinos.

I don't know if this additional baryonic matter they claim to have located is suitably located in space to address the missing galactic gravitational mass problem, that galaxies appear to behave gravitationally as though there is a large halo of additional gravitational mass surrounding them, that so far (except possibly in this Caltech work) we haven't been able to detect, the putative dark matter haloes of galaxies. And, as far as I can see, this says nothing about dark energy.

shpalman wrote: Thu Jun 19, 2025 12:14 pm

IvanV wrote: Thu Jun 19, 2025 11:31 am Caltech claims it has located the "missing matter" in the universe. It is claiming that there is about three times as much baryonic matter (ie protons, neutrons, potentially other triquark particles, "ordinary" stuff we already know about) located in tenuous clouds in the intergalactic medium as there is located in galaxies.

If I understand this right, and Caltech is right, then this is a large part, or maybe even essentially all, of the "dark matter" we have been looking for. And it is ordinary baryonic matter, not made of some kind of particle we have not detected in our particle accelerators, as the string theorists would like. Nor is it stuff we know about but really hard to detect, like neutrinos.

The way it's worded, it looks like they've accounted for the missing non-dark matter, rather than discovered that dark matter just needed to be illuminated better: "Unlike dark matter, ordinary matter emits light of various wavelengths and thus can be seen. But a large chunk of it is diffuse and spread thinly among halos that surround galaxies as well as in the vast spaces between galaxies."

It seems to me like they found that "ordinary matter" which is "diffuse and spread thinly..." and haven't done anything with "The vast majority of matter in the universe [which] is dark—it is entirely invisible and detected only through its gravitational effects".

The preprint of the article is freely available at https://arxiv.org/abs/2409.16952

On November 23, 2023, the three observatories detected a signal, designated GW231123. Unraveling the measurements, scientists found the two black hole components were more massive than any previously seen, 100 and 140 solar masses. The final black hole mass was about 225 times the mass of the Sun; the missing 15 solar masses were converted into gravitational waves during the merger.

bjn wrote: Mon Jul 14, 2025 7:33 pm Some people did some sums on a black hole merger that was detected in 2023.

On November 23, 2023, the three observatories detected a signal, designated GW231123. Unraveling the measurements, scientists found the two black hole components were more massive than any previously seen, 100 and 140 solar masses. The final black hole mass was about 225 times the mass of the Sun; the missing 15 solar masses were converted into gravitational waves during the merger.

15 solar masses (3 x 10^48 Joules) is a rather large amount of energy to emit in the short period of time of the merger. The power output exceeded that of all the stars in the known universe, but radiated as gravitational waves. Egads.

https://badastronomy.beehiiv.com/p/the- ... ba789d58bd