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.
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.
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.
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.
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?
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.
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.
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.
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.
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.
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.
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’.
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.
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.
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).
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.
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.
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.