Science Notes (3/21/25)

I’ve written here before about the Libby app I use to access the local library’s ebook catalog. Over the years, I’ve read hundreds of library books without ever having to actually visit the library. (Which is a pity in some ways. I’ve always loved libraries and even was a student librarian in high school. And there is value in being able to wander and browse.)

A while back the Libby app seriously expanded access to periodicals, so I’ve been reading the British magazine, New Scientist.

Which has turned out to be yet another reason to take notes…

What happens is that sometimes something in an article strikes me such that I copy-n-paste a bit of text to my Apple Notes app. A problem is that I rarely copy enough context (let alone any citations) — just the part that struck me.

Which makes these notes fine for me, but the point of making these notes is the vague intention that I might write about them. What actually tends to happen is that my notes pile just gets bigger. And at some point, a bit overwhelming. This Friday Notes series has been my attempt to reduce or even eliminate that pile.

Or at least to leave only the meatier notes I might actually write about.

But when I look at the Science Notes in the app, I realize I typically haven’t saved enough references or context to write adequately (let alone effectively) about the note. Obviously, I need better note-taking skills.

Perhaps related to what the political turmoil is doing to our minds (in my case causing severe ennui and disconnection), I realized this week that I hadn’t made any Science Notes since last December. And the notes I have are getting long in the tooth.

So, for whatever it may be worth, I’m dumping them here. If for no other reason than to remove them from my phone.

Another chance encounter

The solar system encountered turbulence on a galactic scale between 2 million and 3 million years ago, colliding with a dense interstellar cloud that may have altered both the climate and evolution on Earth.

Merav Opher at Boston University and her colleagues have used the European Space Agency’s Gaia satellite to uncover evidence that a dense hydrogen cloud, the Local Ribbon of Cold Clouds in the constellation Lynx, probably crossed paths with our sun as both travelled through the interstellar medium, the vast space between star systems.

Opher and her colleagues mapped the location of the dense cold cloud and the past trajectory of the sun. They propose that as the solar system collided with the cloud, it battered and shrank the heliosphere, the protective bubble.

The researchers think the heliosphere shrunk so far that Earth was left exposed outside the protective cocoon, possibly for as long as 10,000 years (Nature Astronomy, doi.org/m284).

I’ve also read about how the Solar system (and thus Earth) passed through a dust cloud somewhere in the 10,000 or so years ago frame, if I recall correctly. The authors in that one mentioned that the dust may have been thick enough to dim the sunlight somewhat.

More to the point, I’ve written quite a bit about the Fermi Paradox [see all these posts] and most particularly in this case, about the Simple Probabilities outlook that I find more compelling than the famous but vague Drake equation (which leaves the probability factors as a user exercise).

As you’ll recall (if you read those posts), my math puts the odds of intelligent life evolving at 10²⁴ — based on there being at least six required events with odds at a mere 1-in-10,000. The context is that there are only about 10²² stars in the visible universe (and only 10¹¹ in this galaxy).

The events I have in mind include such things as what the Solar system may have experienced during its history. For instance, passing through voids (we’re in one now) or dust clouds or cold clouds of hydrogen. Who can say what factors were a part of how life evolved here.

Of course, these days we’re confronted with perhaps a more compelling explanation of the Fermi Paradox. If we’re a typical example of “intelligent life” then it seems intelligent life is too stupid to ever amount to much. Let alone colonize the stars.

Why War?

This persistence of war both defies and demands explanation. Many have tried. Albert Einstein felt driven to seek an (ultimately inconclusive) written exchange with Sigmund Freud on the subject, published as Why War? A number of books have since shared this title, the latest by historian Richard Overy.

…

Elsewhere, early attempts by psychoanalysts to explain war as “an act of collective insanity” proved a dead end. But Overy recognises social psychology’s role in explaining how both hunter-gatherers and industrialised nations can dehumanise their opponents to the point of engaging in corpse mutilation, massacres and even genocide.

Many anthropologists viewed modern humans as descending from more egalitarian and peaceful ancestors. That view, says Overy, has been undermined by archaeological evidence of skeletal trauma such as embedded projectiles and cranial injuries, and sites with clues that suggest massacre and cannibalism.

I don’t know that we really need to look that far for an explanation. Humans are shits, pure and simple. Our past literature and art show what heights we can rise to when we set our minds to it, and it is that literature and art that I’ve long held as normative (but perhaps is actually extraordinary).

But lately our literature and art seem more to wallow in the depths we can sink to. And one need only look to chimps for an example of what darkness lurks in our collective hearts. Or to look at our own history of torture, mutilation, delivering death. We’re really good at it.

I think it’s a complex form of intellectual entropy. Fighting entropy takes energy, and when we don’t apply that energy to rising to our potential heights, we naturally sink into our potential (and usually actual) depths.

One can also consider the key points of “cosmic sociology” from the Three Body Problem trilogy by Liu Cixin (the actual series title is Remembrances of Earth’s Past).

Ye Wenjie gives Luo Ji two axioms:

1. The primary goal of any civilization is survival.
2. All civilizations grow without limit, but resources are finite.

She also introduces two accompanying ideas:

1. Technological explosion: a civilization can have extraordinary advances in technology at any time (meaning you can’t count on a “lesser” civilization deemed not a threat remaining not a threat).
2. Chain of suspicion: No civilization can trust another apparently benign civilization to remain benign. In part because that benign civilization will fear that you will not remain benign. This quickly turns into ‘I think that you think that I think that you think that I think…’

The end result is that any galactic civilization aware of another should destroy that other civilization to protect itself. Because the galaxy is a Dark Forest.

Bottom line: I suspect we war simply because of the two axioms above (and that we’re not nearly as evolved or intelligent as our PR suggests).

Assembly Theory

To investigate how humble beginnings can lead to complex ends, Ben Laurie at Google and his colleagues designed experiments where tens of thousands of separate pieces of computer code randomly mingled, combined and executed their instructions over millions of generations.

Because there were no rules to govern how the code samples should change and no rewards for certain behaviour, the researchers expected the population – which was capped at a fixed number – to remain random and do nothing coherent. But to their surprise, they found that the simulation eventually led to the emergence of self-replicating programs that quickly multiplied to hit the population cap. Eventually, new types of replicators emerged that competed for space and occasionally overwhelmed and replaced the previous population, just as biological organisms can outcompete each other (arXiv, doi.org/m676).

Again, the situation of potential growth without limit in the context of finite resources. This experiment provided bits of code and some sort of rules by which they could combine. Given such a system, especially if something acts as a selective force, it can be surprising how quickly it evolves to a complex end state. [For an example, see String Evolution.]

More to the point, I’m fascinated by how reality seems to offer a counter to entropy in how simple building blocks, a few rules, and then stirring in energy and time, leads to complex structures arising. This seems almost in defiance of the fundamental lesson of thermodynamics: everything decays. This magic doesn’t seem to me that it should necessarily be the case.

Yet we exist because it is. That might be our miracle of creation (or God).

Gold

Quartz samples that weren’t subjected to pressure didn’t attract gold, but those that were generated a voltage and attracted the metal (Nature Geoscience, DOI: 10.1038/s41561-024-01514-1). Once gold started depositing on the quartz, it rapidly attracted more, says Voisey. “Because gold is a conductor, there’s a preferential bias for gold in solution to deposit on pre-existing gold,” he says. “It becomes like a lightning rod that attracts more gold.”

“At cold temperatures of just billionths of a degree above absolute zero, quantum effects make atoms behave like “matter waves” rather than particles.”

Cool, but I’m not sure how the second paragraph applies considering that temperatures that close to absolute zero exist nowhere on Earth except a few laboratories. I almost wonder if it was a note from something else that got merged with the one about gold. (Which answers the question about why we find nuggets of gold occurring naturally.)

Gold is one of those bullet points in my 10²⁴ odds against “intelligent” life (yeah, I think I will have to put that in quotes from now on). Not the gold per se, but that it and other heavy metals exist on Earth. That requires a supernova or neutron star collision in our neighborhood in the relatively recent past. And if gold or other heavy elements are somehow required for life — and there is reason to believe so — then that astronomical catastrophe is one of those 1:10,000 events necessary for me to be writing this post.

Math

Why do we fear mathematics? At heart, says Auerbach, it comes down to a fundamental misunderstanding of what maths is. The fear of messing up a calculation may be real, but the fact that there are many excellent mathematicians who are terrible at arithmetic proves that numeracy and mathematics aren’t the same thing.

We understand this about writing literature. The art of creating a compelling narrative in beautiful prose is different from the technical skill of getting the spelling and punctuation right. The same is true with maths. It isn’t mere calculation.

Some very cool food for thought and my favorite among this set of notes. I’ll let it stand on its own without further comment.

Uranus

Jamie Jasinski at NASA’s Jet Propulsion Laboratory in California and his colleagues have reanalysed the Voyager 2 data and found that it was skewed by a rare burst of solar wind that squashed Uranus’s magnetic field just before the spacecraft arrived, disturbing the readings. This means everything we thought we knew about Uranus’s magnetic field might be wrong, says Jasinski. “This kind of almost resets everything.”

Frankly, I’m often astonished that we can know anything about the greater universe from our perspective down in this gravity well. Of course, Voyager 2 was out in space, but still.

This is a good lesson in the convergence and contingency of science.

Earth’s Core

Cooled too fast. Mixture of other atoms (carbon, etc)?

No clue. The above is my only note, and nothing is quoted from an article. But it was something interesting about the Earth’s core.

Music

To give one example, humans have a remarkable capacity that is rare in the animal kingdom: the ability to predict a regular beat and entrain our bodies to it. This allows us to engage collectively with other humans in complex musical and dance performances, leading to alignment of emotional states, which in turn may have had a very significant impact on the evolution of human societies.

Some animals apparently can get into a beat and dance in time to it (I recall seeing a video of a parrot jumping up and down in time to the beat). I doubt any animal is capable of a rock-n-roll backbeat, though. Syncopation seems a decidedly human trait.

Art, in general, (along with math) seems strictly a product of intelligence, and it would be what I’d look for in alien civilizations. (You know, before we destroy them for our own security.)

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Stay on the backbeat, my friends! Go forth and spread beauty and light.

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