Science: Gravity, Asteroids, Slime Mazes, Speech

Pasadena Village Science Monday, summary of Jan 10, 2022, meeting

Present: Sally A, Sally C, Barbara M, Howard R, Dick M, Bruce G, Charles H, Bob S

Next meeting Feb 14th at 4 PM, sorry to disappoint you, but no speaker for February.

Barbara had sent around one excellent paper and Howard two. Next time that we have

presentations about papers, I will do the same. This makes for a more informed audience.

We began here with Barbara and a paper called What if the universe had no beginning?

We are all aware of the Big Bang Theory, now accepted by almost everyone. Many of us wonder

periodically about what preceded the Big Bang. This paper brings us a relatively new theory of

quantum gravity, casual set theory. Almost all of physics and astrophysics consider space time to be

continuous. But casual set theory does not – it posits chunks or units of space time and a new paper

by Beeto and Xalel works out the formalisms of time according to casual set theory. Casual set

theory that the passage of time is something physical, it should not be attributed to some

emergent sort of illusion or to something that happens inside our brains that makes us

think time passes; this passing is, in itself, a manifestation of the physical theory," Bento

said. "So, in causal set theory, a causal set will grow one 'atom' at a time and get bigger and

bigger."

The theory also neatly removes the problem of the Big Bang singularity because, in the

theory, singularities can't exist. It's impossible for matter to compress down to infinitely

tiny points — they can get no smaller than the size of a space-time atom. 

Without a Big Bang singularity, what does the beginning of our universe look like? The

authors paint an interesting picture but have no proof to support it. It may be a

fundamental attribute of the human brain to assume that everything has a beginning, but

that may not be true. As pointed out at the meeting, ancient Hindus assumed a cyclical

universe without end or beginning. Hinduism is the only religion which includes the

concept of life-cycles of the universe. It suggests that the universe undergoes an infinite

number of deaths and rebirths. 

The best known quantum gravitational theory is string theory, which arose in the 1960s

and has gone through cycles of upgrade with great attention, It has been proposed as a

possible theory of everything, a hypothetical, all-encompassing, coherent theoretical

framework of physics that fully explains and links together all physical aspects of the

universe. That was over the top for an untestable theory and string theory sank into

relative limbo when scientists realized that there was no way currently to prove a theory

which depends on special actions at length scales near the Planck scale, around 10 −35 meters, a scale

far smaller, and hence only accessible with far higher energies, than those currently available in high

energy particle accelerators. This is equally true of Casual set theory. However string theory is

now again in an upcycle.

Barbara’s presentation generated much interest, as did the second of Howard’s two papers.

This paper. What if Math Is a Fundamental Part of Nature, Not something humans

invented? Is well written and has beautiful images, some built from fractals as we might

imagine. The article makes a strong point and I hope has been or will be read by many of

you. I’ll be glad to supply the reference to anyone who wishes it. There’s no question that

descriptions of our world and universe are almost always mathematical, but that’s not

proof. Think of it this way, almost all sounds can be fitted onto a musical scale, Musical

notation is a very useful way to describe sounds, but I don’t think that the making of sounds

requires musical scales. Mathematics provides wonderful descriptions of nature and lets us

test construction projects before starting them. Why does nature follow the rules of

mathematics? It’s really the other way around. Through the millennia of human history,

we’ve tried lots and lots of mathematical models. The ones that work, we keep. the ones

that don’t work, we ditch.

The Romans spread their hash-mark mathematics across Europe with their conquests. That

system was replaced with the Indian number system which was so much more efficient. We

call it ‘Arabic numerals’ because it came to Europe though the Arabic world. Plant and

animal bodies are built according to rules. Mathematics provides increasingly accurate

descriptions of those rules.

Howard’s other paper also sent around was worthwhile; First results from Hayabusa’s

Ryugu asteroid sample. This mission, launched in 2014, met up with the primitive asteroid

Ryugu in 2018 and then spend 18 months circling the tiny asteroid before finalizing

sampling plans. Two samples were taken, one from the asteroid surface and one from

subsurface. material never exposed to the vacuum of space. Total sample weight was a bit

more than 5 grams.

Study of the tiny sample has already revealed much. it’s a C-type asteroid – a dark and

rocky world, rich in carbon and water. These types of asteroids are ancient, left over from

the birth of our Solar System. But the team thought the density of the sample material

would be higher, because the collection and return process should have shaken the

material up and collapsed the gaps between grains.

The sample’s density is also much lower than that of carbonaceous chondrites – perhaps

because the meteorites that end up on Earth have to be hardy enough to survive a fiery

plunge through the atmosphere, and so more fragile chunks don’t make it through.

“Ryugu may also contain more low-density material, such as organic molecules, than such

meteorites,” Grady adds. Ryugu or pieces of it have not passed through our atmosphere.

Another group studied the sample’s composition. It The second group specifically looked at

the sample’s composition and found that it was rich in not only carbon but also hydrated

minerals and clay

It differed from other carbonaceous chondrites that scientists have studied on Earth. The

sample had a fine, uniform texture, and didn’t contain any chondrules – molten spherical

droplets usually found in carbonaceous chondrites. This may suggest that Ryugu is the

parent body of a type of meteorite called a CI chondrite – which are so rare that only five

have ever been found on Earth.

CI chondrites have a chemical composition very similar to the Sun and give us a view of

what the Solar System was like when it first formed. Overall, this study reminds us that

meteorites may not be representative of asteroids, and that asteroids ay change over time.

It’s a pity that we didn’t have time to discuss the Ryugu study. We’ll have a sample from

asteroid Bennu, which we’ve discussed in past months, in 2023.

We had lots of discussion, including discussion about Slime mazes. There are

various primitive organisms called slime molds. Physarum polycephalum is a single-

celled yellow colored organism visible to the naked eye. It’s much bigger than most

cells which can’t be seen without magnification. It’s a protist, not a fungus and its

two vegetative cell types, amoebae and plasmodia, differ markedly in morphology,

physiology and behavior. The plasmodium can learn how to locate food in mazes.

This is amazing in a one celled creature, albeit a multinucleate one. There’s much

evidence of learning by single celled animals, but this is the only report of slime

molds (which can grow to be one foot long = a very peculiar type of cell) being able

to learn mazs.

We finished with a discussion of brain laterality and speech. Hippocrates knew that serious

injuries to one side of the head usually produced paralysis of the limbs on the opposite side of

the body but none of. His surviving writings mention the laterality of speech, We have no clear

discussion of this until the 19 th century and French physician Paul Broca. His star case involved a

man who had a stroke, leaving him with normal hearing and oral motor function, but able to

say only one word, ‘tan’. After he died, examination of his brain showed a single lesion in the

left fronto-parietal area, which we now call Broca’s area. Carl Wernicke reported a different

kind of patient in 1871 who also had a singe brain infarct from stroke, and had a severe

problem, speaking far too much, saying real words interspersed with gibberish. He couldn’t

what others said to him. His lesion was more posterior, involving posterior temporal and

parietal cortex. Neurologists came to speak of anterior and posterior aphasia, but other kinds of

aphasia occurred with other, left sided lesios.

I didn’t want to dwell on this extremely complex subject, but I wanted to discuss the

relationship between speech and handedness in children. People were interested in the

phenomenon of left handedness and in the 1920s, Psychiatrist Samuel Orton at the University

of Iowa set up a clinic for children with various school problems including great difficulty

learning to read, many of whom were ambidextrous or left handed and had normal IQs. Orton

created a theory of mixed dominance. If you had learning/reading problems and weren’t

strongly right handed, you might be suffering from ‘mixed dominance’ for which a variety of

shaky treatments were proposd.

Although many believe today that left handedness is associated with things like dyslexia (like

left handedness the definition of dyslexia is elastic, although it is becoming better defined. The

definition of left handedness remains subjective. Almost all right handers can do some things

better with the left hand or leg. Twin studies confirm that there are genetic influences

on

handedness but they all up to only about 25%. The rest add up to 75% and seem to be highly

complx.

And what about the relationship between handedness and cerebral dominance? 96% of right

handers have left cerebral dominance for language, compared with 70% of left handers. Yes,

most left handers have cerebral dominance for language. There is much to be done.

Unfortunately, we have no speaker for Monday the 14 th in spite of all Howard’s efforts. This

means that we need you to find topics to present – Nope, no time off. Remember all the sources

of Science News from Scientific American to Science Digest to Science News to The Universe

Today weekly newsletter, there’s lots of stuff out there. What about the rogue wandering black

hole only 5,000 light years from us? This has been long-predicted: an isolated black hole drifting

aimlessly through space, born and flung out from the collapsing core of a massive star.

Rogue stellar-mass black holes, long predicted but only now observationally confirmed, might

well be rather common in our galaxy. We’ve gone the once in a lifetime idea or even doubting

the existence of black holes to the current ‘one on every corner’ explosion.

Please be there on Jan 14 th at 4 PM.