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This is an explanation of why my America is so hopelessly heading toward mediocrity or even destruction. This PC that I am using, along with the endless information and psuedo information contained therein, makes it easy for me to be stupid.

#55

Science / Re: new cosmology stuff

Last post by Recusant - February 05, 2026, 05:37:41 AM

OK, the party being the Universe: <Carl Sagan voice>Billions and billions of years</Carl Sagan voice>. If it's life on this planet, it seems likely to me that there will still be living things of some sort here when Earth is engulfed by Sol in its latter times. There are microorganisms living miles below the surface; tiny interstices in the rocks being large caves to them. Even if the surface gets scoured thoroughly, those deep dwellers will carry on.

A giant impact like the one which is thought to have formed the Moon could do it though. Turn the entire surface molten. Assuming the existence of rogue interstellar planets, the unlucky one out of a few trillion chance of such a visitor could rub out active DNA here before the Big Roasting. I'll see whether I can come up with any other ways it could happen, that'll be good for some cheerful contemplation.

If it's our species or its descendants, that could be several thousand years even after we degrade the planet. Homo sapiens is fairly adaptable. This civilization seems intent on bringing its own downfall but some humans will almost certainly survive that.

#56

Religion / Buddha

Last post by Icarus - February 05, 2026, 03:56:46 AM

A religion that is not a religion. This is a video that is worth watching for the few minutes it uses. It seems that HAFers are on a similar page. At least the ones of us who are thinkers or seekers of reality.

#57

Science / Re: new cosmology stuff

Last post by Dark Lightning - February 05, 2026, 03:29:37 AM

Yeah, hard to say how much longer the party will last. I won't see the end, either.

#58

Science / Re: new cosmology stuff

Last post by Recusant - February 05, 2026, 03:08:57 AM

Yeah, the idea of primordial black holes has been around for some time, but by their nature they would be extremely difficult to find. It'd be a cool way to resolve the identity of dark matter though.

It's true that we see the Universe at a point long past the Big Bang. Still, for life as we know it to exist there has to be a liberal sprinkling of elements heavier than hydrogen, helium, and lithium. For that, a few generations of supernovae have to have come and gone. Takes some time. Most likely there is or has been life in the Universe that started a billion years or two before Earth's, but I don't think we're particularly late to the party.

#59

Science / Re: new cosmology stuff

Last post by Dark Lightning - February 05, 2026, 01:54:50 AM

I read that this morning. It'll take us the life of the universe to understand it all, but a lot of its life has already passed us by. Well, it's the ride that counts, I guess. I'm liking that story about binary star pairs tossing one star off at stupendous velocities. Wild universe.

#60

Science / Re: new cosmology stuff

Last post by Recusant - February 05, 2026, 12:40:28 AM

Further speculative cosmology. As long as it could give an accurate idea of our Universe, I'll listen. May not buy the idea but there's nothing wrong with some window-shopping. Evidence of an extraordinarily speedy neutrino could indicate the existence of primordial black holes (PBH). More specifically, exploding primordial black holes.

"Did we just see a black hole explode? Physicists think so—and it could explain (almost) everything" | Phys.org

QuoteIn 2023, a subatomic particle called a neutrino crashed into Earth with such a high amount of energy that it should have been impossible. In fact, there are no known sources anywhere in the universe capable of producing such energy—100,000 times more than the highest-energy particle ever produced by the Large Hadron Collider, the world's most powerful particle accelerator. However, a team of physicists at the University of Massachusetts Amherst recently hypothesized that something like this could happen when a special kind of black hole, called a "quasi-extremal primordial black hole," explodes.

In new research published in Physical Review Letters, the team not only accounts for the otherwise impossible neutrino but shows that the elementary particle could reveal the fundamental nature of the universe.

Black holes exist, and we have a good understanding of their life cycle: an old, large star runs out of fuel, implodes in a massively powerful supernova, and leaves behind an area of spacetime with such intense gravity that nothing, not even light, can escape. These black holes are incredibly heavy and are essentially stable.

But, as physicist Stephen Hawking pointed out in 1970, another kind of black hole—a primordial black hole (PBH), could be created not by the collapse of a star, but from the universe's primordial conditions shortly after the Big Bang. PBHs exist only in theory so far, and, like standard black holes, are so massively dense that almost nothing can escape them—which is what makes them "black." However, despite their density, PBHs could be much lighter than the black holes we have so far observed. Furthermore, Hawking showed that PBHs could slowly emit particles via what is now known as "Hawking radiation" if they got hot enough.

"The lighter a black hole is, the hotter it should be and the more particles it will emit," says Andrea Thamm, co-author of the new research and assistant professor of physics at UMass Amherst. "As PBHs evaporate, they become ever lighter, and so hotter, emitting even more radiation in a runaway process until explosion. It's that Hawking radiation that our telescopes can detect."

[Continues . . .]

The paper is behind a paywall, but I found an open access preprint version. The abstract is from the published version and I nominate its final sentence as an exemplary "big if true":

"Explaining the PeV Neutrino Fluxes at KM3NeT and IceCube with Quasi-Extremal Primordial Black Holes" | arXiv

QuoteThe KM3NeT experiment has recently observed a neutrino with an energy around 100,PeV, and IceCube has detected five neutrinos with energies above 1,PeV. While there are no known astrophysical sources, exploding primordial black holes could have produced these high-energy neutrinos.

For Schwarzschild black holes this interpretation results in tensions between the burst rates inferred from the KM3NeT and IceCube observations, with indirect constraints from the extragalactic gamma ray background and with the non-observation of an associated gamma ray signal at LHAASO.

In this letter we show that if there is a population of primordial black holes charged under a new dark 𝑢(1) symmetry which spend most of their time in a quasi-extremal state, the neutrino emission at 1,PeV may be more suppressed than at 100,PeV. The burst rates implied by the KM3NeT and IceCube observations and the indirect constraints can then all be consistent at 1𝜎, and no associated gamma-ray signal was expected at LHAASO. Furthermore, these black holes could constitute all of the observed dark matter in the universe.

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