Tuesday/ where the signal meets the muscle

I played a little social tennis tonight on the Woodland Park tennis courts. We rained out on both Tuesday and Thursday of last week, so it was great to finally get out and play.

And hey! the muscle memory from many years of playing tennis is still there, sending signals to the old muscles and creaky bones— to run down that incoming shot, and strike it, so it goes back over the net.

Muscles need electrolytes (salty water) to function. A neuromuscular junction (or myoneural junction) is a chemical synapse (connection that allows a signal to pass), formed by the contact between a motor neuron and a muscle fiber. It is at the neuromuscular junction that a motor neuron is able to transmit a signal to the muscle fiber, causing muscle contraction. Here is what happens, all of it in a millisecond or so! (1) The electric signal’s action potential reaches the axon terminal. (2) Voltage-dependent calcium gates open, allowing calcium to enter the axon terminal. (3) Neurotransmitter vesicles fuse with the presynaptic membrane and acetylcholine (ACh), a small neurotransmitter, is released into the synaptic cleft via exocytosis. (4) ACh binds to postsynaptic receptors on the sarcolemma (membrane on the muscle fiber). (5) This binding causes ion channels to open and allows sodium and other cations to flow across the membrane into the muscle cell. [Source: Wikipedia]

Saturday/ we have to stop burning coal

The Keeling Curve from the website of the Scripps Institution of Oceanography at https://scripps.ucsd.edu/programs/keelingcurve/. It sure looks as if the Industrial Revolution (1760 – 1830) has been – and still is – a global catastrophe.

When I was a kid, we would build a cozy wood fire in the living room fireplace in winter time. On top would go a layer of anthracite (hard black coal, with a metallic luster on its surface), to make the fire glow a long, long time.
But then I would go to school the next morning, and the neighborhood’s chilly winter air would be blanketed by a layer of thick smoke. Man! I thought .. this is not good.

Now here we are, 50 years later, and I read about the Australian elections, and the saga of the contentious Carmichael coal mine in Queensland. The mine will be ‘hugely beneficial’ to Australia and ‘global climate change’, says Adani CEO Jeyakumar Janakraj. Really? Yes, your $16.5 billion project will create a few thousand jobs, but pump up to 12 billion litres of water a year from the Suttor River. It will gouge out 60 million tonnes of low-grade coal every year from the Galilee basin right across the Great Barrier Reef. The coal will get burned in India and push up the 415 parts per million CO2 concentration we already have in the atmosphere.

Adani Australia, throwing in an image of black-throated finches into their Twitter propaganda campaign .. but ultimately it is not about the finches or the endangered yakka skink in Queensland. Climate change is real and humans are accelerating it by burning fossil fuels.


Saturday/ the gnomon sundial at the UW

What you seek is but a shadow.
– the motto on the University of Washington sundial.

With all the sunshine we had this week, I thought it was high time for me to understand how the sundial on the Physics building at the University of Washington works!

In the picture below, the shadow of the gnomon (ball) moves from left to right as the day progresses. The sun crosses lower in the sky in winter time, and then the path on the wall is higher. The sun crosses higher in summer time, and then the path on the wall is lower. The equinox was in March, so we have already crossed to below the line marked EQUINOX on the sundial.

The only other thing that seemed out of whack, was that the dial seemed a little off: it showed 12.30 pm PDT on the nose, when it was already 12.39 pm when I took the picture. Should the gnomon ball shadow not have moved at least a little bit off the 12.30 pm line, towards the 1.00 pm line?

We in Seattle, and all others in the Pacific Standard Time zone, keep a clock time based on the solar time at the arbitrary longitude of 120° W (which happens to pass through the town of Chelan). However, in Seattle we are located some 2° 19′ to the west of this longitude, and the sundial in Seattle indicates a time 9.2 minutes earlier than the sun would in Chelan. Here is the full explanation from the UW Dept. of Physics.

P.S.  Look for the slender figure-eight-shaped curve in the sundial’s center by the 12, called the analemma. It is a plot of the location on each day at noon, throughout the year, of the gnomon ball’s shadow.

The UW sundial at 12.39 pm PDT on Thu May 9, 2019. (I marked up the shadow of the arm and the gnomon ball in black, so that it shows clearly). The dial is on the side of the University of Washington’s Physics/Astronomy Auditorium at 3800 15th Ave NE. It was installed in 1994 under the supervision of Prof. Woody Sullivan, then-Professor of Astronomy.

Thursday/ there is Pikachurin in your eye

I was at the eye doctor today for my biannual check-up (all good). Since part of the test was a retina scan, I thought I’d refresh my knowledge of rods and cones in the retina. The human retina contains about 120 million rod cells, and 6 million cone cells. Check out the diagram below for a primer on how the retina works.

Biologists are still learning about all the cells and proteins and chemistry involved in vision. For example, in 2008 a team of Japanese researchers discovered a lightning-fast protein involved in the precise interactions between what is called the photoreceptor ribbon synapse and the bipolar dendrites. They promptly named the protein Pikachurin, after Pikachu, the lightning-fast Pokémon creature.

[Source: Arizona State University ‘Ask a Biologist’ https://askabiologist.asu.edu/rods-and-cones]. 1. Light moves through the lens of the eye to the back of the eye, which is the retina. Here, there are millions of rods and cones. 2. When light hits the discs in the outer segment of the rods and cones, the little bits of light (photons) activate the cells. Rods can be activated in low light, but cones require much brighter light (many more photons). Most of the light not absorbed by the rods or cones is absorbed by the epithelial cells behind them. The discs of rods hold rhodopsin and the discs of cones hold photopsin. Both of these photoreceptor proteins are special molecules that change shape when activated by light. This shape change allows the proteins to activate a second special protein molecule that then starts causing other changes involved in sending a visual signal. For the signal to be sent through the cell, charged molecules called ions are let in and out of the cell in an action potential. 3. When the signal reaches the inner end (left side) of the rods and cones, the signal is passed to sets of neural cells. 4. The signal moves through neural cells in the optic nerve. 5. The optic nerve will send this information to the brain, where separate signals can be processed so you see them as a complete image.

Wednesday/ there it is: a black hole

Google made a great doodle of the first-ever image of a black hole ●. This black hole is in Messier 87 (abbreviated as M87), a giant galaxy in the constellation Virgo. The black hole is several billion times more massive than our Sun. Lucky for us, it is about 53 million light years from Earth.

What will happen to a human falling into a black hole? Based on the mathematics in Einstein’s general theory of relativity of 1915, you would fall through the event horizon unscathed, then the force of gravity would pull you into a very long noodle and ultimately cram you into singularity, the black hole’s infinitely dense core. Ouch?

Images of the M87 black hole. [Source: New York Times]. The line and the 50 μas shown in the picture is 50 millionths of an arc-second, an angle unit of measure. That is a vanishingly small sliver of an angle that the radio telescopes had to pin down. For comparison, the angular diameter of the Sun comes in at 32′ (minutes) and that of Venus at about 1′ (one minute). One degree equals 60 minutes, one minute equals 60 seconds.
The elements of a black hole. Black holes were predicted by Einstein’s general theory of relativity that was published in 1916. [Diagrams and article: The Guardian newspaper].

Tuesday/ Our Planet: can we save it?

The spectacular – and spectacularly upsetting, it looks like to me – Our Planet series of episodes from renowned filmmaker Sir David Attenborough (he’s 92) is set to debut on Friday on Netflix in 190 countries. It may draw a total audience of one billion viewers.

The material has been four years in the making, with filming done in 50 countries and with the collaboration of the World Wildlife Fund. No bones are made about the impact that human activity has had on the planet. Humans are accelerating what is called the Sixth Extinction, of plant and animal species across the globe.

Below is a preview and a few photos from the series, that the Irish Times had published over the weekend. The octopus in the last picture is off the coast of South Africa.


Wednesday/ the super worm equinox moon

Spring has arrived here in the North.
We experienced freakishly warm spring temperatures here in the city yesterday and today: 79 °F (26 °C).

A supermoon tonight coincided with the start of spring, the third and final supermoon for the year. (A supermoon is called a perigean full moon by astronomers. It occurs when a full moon reaches its closest point to the Earth in its elliptical orbit, making it appear unusually bright and large).

The ‘worm’ in the moon’s description refers to little creatures like worms that resume squirming out of the ground, along with the leaves and flowers that start budding in spring.

Here’s the early evening’s full moon from my upstairs window tonight.  The full moon occurred only 4 hours after the spring equinox, the shortest time between the two events since March 1981.
Gorgeous picture of the supermoon, as seen from the International Space Station [Source: @NASA on Twitter]

Saturday/ shocking, but true: Earth is round

We watched ‘Behind the Curve’ tonight: a Netflix documentary about Flat Earthers. For these people, no ‘conspiracy’ is too big to discount. They say that NASA lies and has conspired for decades to portray Earth as round. They find each other on Facebook groups and Youtube videos, and at conferences, prominent Flat Earthers are treated as celebrities that advocate for ‘the truth’. (The conferences are more about commiserating with each other for being outcasts, than they are about explaining the logical basis for saying that Earth is flat).

One of the main protagonists in the movie is from Whidbey Island, a stone’s throw from Seattle. (Dude. We don’t know you, but stop embarrassing us!). The documentary makes the case that Flat Earthers should not be dismissed & shamed outright, since that will entrench their kooky views even further, and completely marginalize them. The problem is that one cannot use reason to argue with a cultist.

This conspiracy theory mindset bleeds into all kinds of other areas. We have people in the United States that believe that 9/11 and Sandy Hook were perpetrated by the US government, and that mass shootings are staged with ‘crisis actors’. People don’t vaccinate their children. We had a recent case here in Oregon with an unvaccinated boy that almost died from tetanus. It took 57 days in hospital and $800,000 to treat him.  His parents took him home and still refused to get him vaccinated.

Saturday/ what was that? -the mystery of ‘Oumuamua

Was our solar system visited (in 2017) by a probe sent by an alien civilization? Astrophysicist Avi Loeb (from Harvard University in Cambridge, MA) explains why it is possible, in the January issue of the German magazine Der Spiegel.
1 The Intruder On October 19, 2017, the Pan-Starrs Telescope in Hawaii discovered a strange elongated cigar-shaped celestial body. It moved so fast that it could not be part of our solar system. It had to be a foreign object, and was called ‘Oumuamua (Hawaiian for ‘First Messenger from Afar’).
2 Strange Coincidence It is comparatively rare that asteroids from distant star systems get lost in our solar system. According to Loeb, the likelihood of seeing such asteroids through Pan-Starrs is somewhere between 1 in 100 and 1 in 100,000,000.
3 Flashes The brightness of ‘Oumuamua fluctuates: the object rotates and reflects, due to its special shape, different amounts of sunlight. The effect is so pronounced that ‘Oumuamua would have to have a bizarre, elongated form – something which does not occur in celestial bodies of our solar system.
4 Enigmatic Trajectory ‘Oumuamua shows a trajectory departure from that known for comets that leave a trail of gases (typically surface ice that evaporates). Also, neither a comet tail could be observed, nor did the rotation of the object change, as would be expected with loss of mass due to gas emissions.
5 Not Solar Powered For Avi Loeb, the only other assumption could be that the solar power (radiation pressure) affected the trajectory of ‘Oumuamua. However, this force is so weak that it could only affect bodies with a large surface area and tiny mass, such as a paper-thin sail.
6 Not Space Junk If such an artificial light sail or other object reached our solar system by accident, one would have to assume that in space such foreign artefacts would abound (which is not the case). So this possibility also seems unlikely.
7 Alien Mission Loeb therefore suspects that an extraterrestrial civilization has purposefully sent ‘Oumuamua as an exploratory probe in our solar system.

The mystery of ‘Oumuamua, explained with pictures in the Jan 5, 2019 issue of Der Spiegel.

Sunday/ tonight’s super blood wolf moon

Here are my (amateur quality) pictures I took of tonight’s super blood wolf moon* as it went into eclipse. It’s the first total lunar eclipse visible across the entire United States in eight years.

*Super because it appears about 10% bigger than it really is; blood because of its coppery color (red light from the sun bent around Earth, reaching it); wolf because it is the first full moon of the calendar year.

From left to right: 6.34 pm Full moon | 7.46 pm Start of the eclipse | 8.18 pm Three-quarters eclipsed | 8.33 pm Eclipse almost complete with red/ copper color showing (all times Pacific Standard Time).
The moon spent some 3 hrs in Earth’s shadow. The diagram below left shows the refraction of the sunlight as it hits Earth’s atmosphere, that results in the red coloring of the moon. [Source: NRC Handelsblad newspaper 19/1/ 2019]

Friday/ the tetanus booster shot

I got a tetanus booster shot this week (recommended by the CDC to be done every 10 years for adults).

The vaccine offers protection against a troublemaker bacterium called Clostridium tetani. Its nearly invincible spore form can be commonly found in soil. So stepping onto a rusty nail with bare feet – or really any cut in the skin – can let the bacterium in. Once inside one’s muscle tissue, it can start producing tetanospasmin, a toxin second only to botulinus for potency. The toxin attacks the central nervous system. An early symptom of an attack includes spasming of jaw muscles.

The tetanus vaccine contains tetanus toxoid, a chemically sterilized tetanus toxin that stimulates one’s immune system to produce antigens that are able to attack and dismantle active tetanus toxin.

Cartoon from the website Telus World Science that explains what tetanus vaccines are all about.

Monday/ the cosmic perspective

I have finished reading Neil deGrasse Tyson’s quick-read book called Astrophysics for People in a Hurry.  In the front is a quotation from Tyson, that I love: ‘The universe is under no obligation to make sense to you’.

Humans have certainly made strides to understand the mysteries of the universe, but we need another Newton, another Einstein, to help us out with understanding what we now call dark matter and dark energy.

Towards the end of the book, Tyson also offers: The cosmic perspective opens our eyes to the universe, not as a benevolent cradle designed to nurture life, but as a cold, lonely, hazardous place, forcing us to reassess the value of all humans to one another’.

This picture is not in the book, but the epochs shown in it are described. The Inflation Theory proposes a period of extremely rapid (exponential) expansion of the universe during its first fantastically short instants of time. Then it took 380,000 years for the temperature to come down to 3,000 K for atoms to form. Right now we are at the 13.8 billion year mark, and the universe is expanding at an ever increasing rate – something we have only learned over the last few decades. The best explanation is that dark matter and dark energy are at work. [Picture courtesy of Particle Data Group, 2015].

Friday/ shocks & aftershocks in Anchorage

Report from the Alaska Earthquake Center:
‘A magnitude 7.0 earthquake struck just seven miles north of Anchorage at 8:29 am on Friday morning, at a depth of about 27 mi (40 km). The earthquake caused power outages, damage to roads and buildings, and closures of schools, businesses and government offices. The extent of the damage is not yet clear, and we are still waiting for word on whether there were any casualties.

This is the largest earthquake to strike near Anchorage since the 2016 M7.1 Iniskin earthquake. Because this morning’s quake was so much closer, the impacts to Anchorage and Mat-Su are far more severe and widespread’.

The USGS aftershock forecast is as follows:

  • Low (4%) probability of another earthquake equal or greater than magnitude 7.0;
  • 27% chance of a magnitude 6+ aftershock, and it is most likely that 0-3 of these will occur;
  • 78% chance of magnitude 5 or greater aftershocks, but likely no more than around 20 of these;
  • Up to 2,200 aftershocks greater than magnitude 3 are possible.
This map from the University of Alaska’s Earthquake Center, shows that the 7.0 event was only one of many smaller ones that preceded it, and that several aftershocks followed.
Tectonic map of Alaska and northwestern Canada showing main faults and historic earthquakes [Source: Wikipedia ‘Denali Fault’/ map by USGS]. There was a really big one in 1964: the Great M9.2 Alaska Earthquake and Tsunami of March 27, 1964.

Wednesday/ Big K is going away

The original International Prototype Kilogram (Big K), safe within three vacuum-sealed bell jars. Credit: BIPM

The kilogram is currently defined as the mass of a chunk of platinum-iridium alloy created in 1889, that is housed at the International Bureau of Weights and Measures in Sèvres, France. (Le Grand kilogram, or Big K, as it is affectionately known).

But what if Big K gets stolen, or damaged? And it has already (mysteriously) lost some 50 micrograms since 1889. So this state of affairs will not do for the 21st century.

This Friday in Versailles, a gathering of the International Bureau of Weights and Measures, is expected to vote to redefine the kilogram by its existence as a unit in the Planck constant.  This new definition is very complicated to explain (see here).  For it to work, the Planck constant also had to be precisely defined and fixed to 9 significant digits, with the aid of a Kibble balance.

And voila!

Wednesday/ it’s going to rain

There is finally some rain on the way for Puget Sound, after a long stretch of dry weather. The meteorologists can see the systems approaching from way out west over the Pacific Ocean.

Below are some high-speed photographs of falling water drops, from an article published in 2009 by Emmanuel Villermaux. He wanted to study how big raindrops behave, as they make their way down to the ground. Raindrops of all sizes can come out of clouds, as the tiny drops (20 µm) combine to make bigger ones. But really big drops will flatten as they fall through the air, into little pancakes, then turn into little bags, and then break up altogether. So drops that reach the ground are at most 6 mm (0.25 in) in diameter. The terminal velocity of a rain drop is about 10 m/s (20 mph).

Saturday/ chameleon of the seafloor

I love this picture of an octopus, the ‘chameleon of the seafloor’. The skin of an octopus is like that of a pointillistic work of art: it has millions of chromatophores (cells with pigments). Octopuses have yellow, orange, reds, browns or even black pigments, and can camouflage itself against its background when an enemy approaches.  There is a complex connection between its brain, its nervous system, and the nerve cells that control the color of its skin.

Source: Dutch newspaper NRC Handelsblad. Picture by Stephan Junek.

Tuesday/ here comes Michael

Hurricane Michael will make landfall in the Florida panhandle tomorrow. It’s going to pack a powerful punch, with winds that could exceed 100 mph. At least it is projected keep moving at a steady pace, and not sit in one place like Florence did.

Source: the National Weather Service.
Update from Wed 10/10 from the New York Times: The hurricane made landfall as a Category 4, with winds of 155 mph (250 kph), unheard of. Its winds rapidly picked up speed as it approached the Florida panhandle.

Monday/ repairs after the rains

Light rain is finally starting to fall here in Seattle, after the driest summer on record. (Rainfall for May-August was 2.5″, compared to 7.0″ normally).

Here’s another one of my resident European garden spiders (Araneus diadematus), repairing its web today, from a little wind and rain damage.

Spider silk is more durable and elastic than even the strongest man-made fiber, Kevlar, which is used to fill bulletproof vests. Silk is mainly protein, but a single spider can produce as many as seven different silks from its spinnerets. The silks in the radial lines, and the spiral lines in this web are different, and the spider also dots the radial lines with sticky balls of silky goo. Watch out, flying insects.

Monday/ a spider, to frighten miss Muffet

‘Little miss Muffet sat on her tuffet,
eating her curds and whey.

Along came a spider
who sat down beside her

and frightened miss Muffet away’.
— Nursery rhyme that first appeared in print in 1805, in a book titled Songs for the Nursery. Its origin is not known.

I found this European garden spider (Araneus diadematus) by my garage today. These spiders are orb-weavers and found throughout Europe and across North America.

Monday/ a little walk in the woods

We did another little walk in the woods today – just through a woodsy area near Paul’s house here in the Hansville area.

The trail is dry this time of year, but can get squishy and muddy in some places, in the rainy season. So the planks covered with chicken wire are a nice addition.
This is a parasitic bracket fungus. It grows on fir tree bark. The genus is probably Fomitopsis (I found similar pictures online). Ötzi the Iceman (5,000 yr-old mummy found in the Alps in 1991), had similar kinds of fungi with him. The fungus could be used for food, but also as tinder (to start a fire with).
I don’t know what kind of spider this is, but I love the geometry of its web, and the rainbow tints that some strands get as the sunlight strikes it.
Here is a belted kingfisher (Megaceryle alcyonis) with its jaunty head feathers. I was not quite close enough to the little bird for a sharp picture, but the camera’s 135 mm zoom helped a lot.
I had better luck with an osprey (Pandion haliaetus), sitting closer to me in a tree on the high bank. I had to wait for it to take off to get a clear shot at it, though.
Here’s the Agate Pass Bridge (constructed 1950) on our way back to the Bainbridge Island ferry terminal.
And here comes Seattle downtown, as we approach it from Bainbridge Island. That’s the Celebrity Infinity cruise ship on the left, in from Vancouver, and setting sail on Tuesday morning for Astoria, Oregon (final destination San Diego). The ship was launched in 2001, and can accommodate 2,500 passengers.