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Grand Canyon – Sweet

So I asked my question.

“I was here 50 years ago. How much has the Canyon eroded since I was here last?”

I was standing at the edge of the South Rim of the Grand Canyon in Arizona. I was talking to a park ranger who looked like she would appreciate my curiosity – and also looked like she would know the answer.

She answered, “The Canyon erodes about the thickness of a piece of paper each year.”

“So,” I said, “that’s 50 sheets of paper, a tenth of a ream, about three-quarters of an inch. I thought I saw the difference.”

And yes, I did see a difference. Not when I peer over the edge and look outwards towards where I can see the Colorado River, but when I look around. There are more people at the Canyon then there had been in November of 1973. The Park is more modern. The trails look better than they had 50 years ago. But the trail down into the Canyon looked just as challenging.

In both my visits to the South Rim, 50 years ago and now, there was snow on the ground. The snow adds to the beauty of the Canyon, as the rocks and trees and shadow are accentuated by the stark white of the snow. But caution is necessary as the trails can be icy and slippery. But with snow or sun caution is always necessary as with the added erosion of the past 50 years its a long way down – plus a bit.

During this visit I would not hike the South Kaibab trail; I would do my hiking on the rim trail. But in 1973 I wanted to see how far down I could get before I had to come back up at day’s end. I started early in the morning with a light pack that I bought the day before in which I had an extra pair of gloves, some sardines and crackers, and something to drink. I don’t think they sold water in bottles back then. I was layered against the cold and had on my sea-duty rain jacket with a hood. It was heavy over my denim jacket, but it would certainly keep me dry. I also had on my woolen watch cap.

I had my copper bound walking stick and was ready to begin my descent. It was cold and clear, and I was the only person on the trail. It was great. The views of the Canyon opening to me were exhilarating. I could look back millions of years as I passed the rock face of the trail wall. I took time to think of all the history that had passed in the first few yards, and then I was well down into the prehistory of the Earth.

It was the uplift of the Colorado Plateau that allowed the marvel of the Grand Canyon to become. About 70 million years ago tectonic forces lifted an area that is now within Colorado, Utah, New Mexico, and Arizona. As mountains formed and snows and rains fell the nascent Colorado River began its journey off the Colorado Plateau down to the Gulf of California. The River began to cut its way through the uplifted plateau as it sought to reach sea level. As it picked up sediments from its sources it flowed across the uplifted plateau like liquid sandpaper. The rushing River gouged and polished its way down to its present level. As the River grew so did the feeder streams that flowed into it; each cutting its own side canyon. The Canyon sides collapsed as the River cut deeper. This collapse created the width of the current Canyon. Rain and freezing water and trees and wind worked their own patterns of erosion on the Canyon walls, dislodging rocks that would tumble down towards the River below.

And here was another difference. As I hiked down in 1973 I kept an eye on the weather at the Canyon rim. I could l see clouds gathering and knew that it was snowing at the top. After reaching Skeleton Point and eating my sardines and crackers, I knew it was time to turn back in order to get out of the Canyon before the weather worsened. I was trudging up the last half mile in snow, leaving my footprints behind me. The wind was blowing the snow, and I had my hood up. Then I heard something. It sounded like the thumping of distant thunder. I put my hood back so I could hear better. There was a rumble and rattle of above me. I looked up and saw a good size rock rolling down the Canyon side in my direction. I took several steps backwards and watched as the rock landed on the trail where I had been standing and bounded further down and out of sight in the direction of the River.

I had witnessed the process of the Canyon. Things change. That rock is now in a different place and the level of the Canyon floor is now lower. And I can tell the difference.

Permian Basin Texas

There are plenty of sights to see on the road through Texas. The country is starkly beautiful. It’s early Spring and some color is beginning to come to the grasses that line the roads and cover the fields. But one thing that I thought I would see, cattle, well I don’t see too many. But what I do see in the area around Midland Texas are pumps. I am driving through the area of the Permian Basin. Rank upon rank of oil pumps as far into the distance as I can see. If I use Google Earth I can see the area is covered with white specks. Each speck is an area around a pump or derrick where the grass has been beaten down and trucks are parked and various pieces of support equipment lay about. One thing of note is there are a lot of pickup trucks on the road and most are towing an open bed trailer. And they are all in a hurry. They are not being driven unsafely, just in a hurry. Out here time is truly money. it’s the ranks of pumps that draws my attention. As I drive down Interstate I-10 most of the pumps are nodding up and down driven by a massive cam and engine. Each one pulling crude oil out of the ground.

The Permian Basin contains more crude oil than any other location within the United States and is one of the great oil resources of the world.

Like it or not oil and gas extraction is part of our world. It drives industry. It enables us to get around. And this will continue until a different economically dependable energy source is developed. What is the good of extracting and burning the essence of years that passed millions of years ago? The resources that lie in the Permian Basin under Texas and New Mexico were lain in that place during the Permian age. This age preceded the time of the dinosaurs, and ended approximately 250 million years ago. Its end came with in a mass extinction of more than 90% of the species on earth. Then as the continents separated, the remnants of the age were overlain by the sediments of the following eras and were compressed onto the hydrocarbon slurry that is drilled for today.

That drilling provides jobs in Texas. The taxes derived from those jobs built the road I drove down. But the economic reach of the oil extracted from the Permian Basin extends well beyond to local area. It enables many American to drive and to produce and to build. It enables us to create and to sell. But this comes at a substantial price. The burning of the refined extract causes pollution in our neighborhoods and smog in our cities. It pollutes the air and dumps chemicals into the atmosphere. These chemicals included CO2 and other “greenhouse gases” which are causing global warming and causing the acidification of the oceans.

But today I see work and prosperity. I see people going to their jobs, being proud of the work they are doing, and doing good work. But beyond here, the same companies that are operating the wells and refining the oil into the world’s fuel, are also working on what may be “a different economically dependable energy source”, which may power people’s jobs and give them economic independence, and provide them with food, shelter, heathy lives, and pride in their existence.

All 8 Billion of us!

Bent Tree

A snow knee? No, I don’t think so.

When I see a snow knee I know it is the result of massive snows bending a tree over. It is also on a down-hill slope. The tree has been bent by the weight of winter snows in the mountains pushing down, laterally, on its trunk. The tree is generally straight above the knee, as in the Spring it shakes off the snows and grows true. But the knee remains, a tell-tale bend in the tree that shows its survival of passing winters.

This was different. The tree had a bend, but it was lateral to the slope, not down-hill. And here in the rolling hills of Virginia we have not had the amounts of snow generally associated with the snow-kneed trees of the Rocky Mountains of the western United States. Something else had bent this tree.

It was clear what had happened. I could see that the tree had been bent over early in its life. Some other tree or a large limb had fallen and caught the little tree and forced it down to the ground. But the smaller tree’s thin trunk had been flexible, and it did not split. The little tree was pushed done, nearly to the ground, under the weight of it fallen sister.

All signs of the other tree are gone, but the bent tree tells the story of the fall, the crushing blow, and the aftermath.

Sometime in the past, disease or a windstorm caused a tree to fall in these woods. It was likely a large tree, not huge, but about 10 inches in circumference. Or it was a limb that was downed by the same causes. It fell from a tree that may still stands in the forest. When it – tree or branch – fell, it hit the little tree. It bent the smaller tree over and pinned it to the ground. And there they lay. The smaller tree would never be able to right itself due to the weight of the large tree/branch.

But the smaller tree did not give in. Its root structure had not been torn out of the ground and was still intact. The smaller tree was still viable could grow even under the weight of the tree/branch that had crushed it. The top of the smaller tree which lay pressed to the ground died and fell away. Today there is a scar of healed wood that surrounds the rotted spot now so close to the ground. The scar is partially covered by a round, rolled callus of wound-wood. This callus is the tree’s natural response to the injury. The callus seals off the damaged area and protects it from infection.

Today the larger tree/branch is gone. But the smaller tree still lives. It is twisted to be sure, yet even in its captive state, it threw off a new branch that reaches vertically up from its twisted trunk and each year leafs and blossoms with some of the prettiest flowers in the forest. It is a dogwood. Its dense wood helped it survive the blow. Its resilience helped it to live and to grow. And its nature gives flowers and brightness to this patch of the deep woods.

Now it is Winter. In the Spring the tree will again show its toughness and determination, and it will flower.

(*Just_a_Note) – Wallace Broecker

News sources around the world have reported the death of Wallace Broecker. As a climate scientist, he penned an article that was published in the journal Science in 1975. This article was among the early warning calls of the effect of atmospheric carbon dioxide (CO2) to cause a rise in the global mean temperature. Dr. Broecker titled the article “Are we on the brink of a pronounced Global Warming”. Through his article, and many others that followed, the term “global warming” has come into common use and is readily understood by all to imply a continuing rise in the global temperature to the point that it has a detrimental effect on the oceans, wildlife, agriculture, and human society.

As Broecker stated in his 1975 article, “… the exponential rise in atmospheric carbon dioxide content will tend to become a significant factor and by early in the next century [the ‘next century’ started in 2000] will have driven the mean planetary temperature beyond the limits experienced during the last 1000 years.”

Further in the article Broecker predicted, “As the CO2 effect will dominate, the uncertainty … lies mainly in the estimates of future chemical fuel use and the magnitude of the warming per unit of excess atmospheric CO2.” When any of us is outside we can see and often smell the exhaust of the continuing use, and increased use, of fossil (chemical) fuels by the world’s expanding population.

So when in his article Broecker asks, “Are we in for a climate surprise?”, the answer is both yes and no. Yes, it is happening, CO2 continues to clog our atmosphere. But no, in 2019 it is not a surprise.

The 1975 article may be found at – https://blogs.ei.columbia.edu//files/2009/10/broeckerglobalwarming75.pdf

The picture is taken from the 1975 article.

CO2 – the Keeling Curve

Many things lie at the heart of climate change. Fundamental in this is global warming due to the rise in atmospheric carbon dioxide (CO2). The primary source of the CO2 is the consumption of fossil fuels by each and every one of us. We drive our cars, and CO2 is emitted in the exhaust. We turn on lights and use electricity generated from burning coal or gas. These methods of generating electricity result in the emission of CO2. These emissions have a direct effect on wildlife, the oceans, and the weather.

The mention of automobiles might put us in the mind that this problem only started since cars have been around. But it is not just the recent use of fossil fuels, we have been burning coal for a long time. Once emitted by burning of fossil fuels CO2 does not dissipated; it accumulates. Some of the CO2 may be taken up by trees and other plants in their respiration cycle. They take in CO2 and during photosynthesis the CO2 is converted into oxygen (O2). Carbon can be locked up in dead plant material too. When a tree falls in the forest its use is not over. There are kingdoms of plants and animals that will use the dead tree for food and homes in their own lives. As these plants and animals devour the now decomposing tree, they consume the carbon and lock it in their own bodies. But then as they die their carcasses, as small as they are, store some tiny bit of carbon to be released into the atmosphere and earth as the plants and creatures decompose into the earth. Over millions of years the decomposition of ancient organic matter, dead plants and animals, has produced the current fossil fuels that we use.

But how do we know that the level of atmospheric CO2 is increasing? First we can read the levels of atmospheric CO2 in ice cores. These cores are from specialized drills that penetrate deep into glaciers. When the core is drilled and extracted for examination, the levels of CO2 from past centuries can be measured. As the drill goes deeper and deeper into the glaciers the cores show what the atmosphere was like in the times past. The deeper the core is drilled, the further back in time the sample goes. When snow and ice accumulated on the surface of the glacier centuries ago it captured a signature of the gases that made up the atmosphere. From these cores the CO2 from ancient fires, and human use of wood and coal as a fuel, and emissions by ancient volcanoes can be studied. It has been established that accumulation of CO2 in the atmosphere has been going on from preindustrial times, hundreds of years ago. Since the introduction of factories and industry that used fossil fuels to operate and manufacture goods, the CO2 in the atmosphere has increased at a higher rate.

A key tool in understanding the increase of CO2 in the atmosphere has been the work of Charles D. Keeling. In 1956 he began a program to measure atmospheric gases, including CO2, at the Mauna Loa observatory in Hawaii. As these observations are plotted over time, they show an increasing level of CO2 with each passing year. The graph that shows this increase, known as the Keeling Curve, also shows the change of the seasons in the northern hemisphere. The upwards spikes of the saw-tooth curve indicate rising CO2 in the Winter months when the leaves are off the trees and are not converting CO2 into O2. The downward slope of each “tooth” indicates the activity of the trees and other plants in the growing seasons of Spring and Summer as they remove CO2 from the atmosphere and convert it into O2. But with each passing year the curve goes every upward.

From these two studies, we can determine that CO2 continues to increase based primarily on human activity. The rising levels of CO2 in the atmosphere result in a continually rising average global temperature. This is due to the greenhouse effect as the CO2 and other gases trap energy from the sun in the atmosphere. The rising levels of CO2 also result in ocean acidification.

A copy is the Keeling Curve from the Scripps Institute CO2 program is inserted below.

The Scripps Institute CO2 program website may be found at http://scrippsco2.ucsd.edu/

Golden Apples

Planned obsolescence, a one-way trip, will be the demise of the Parker Solar Probe. It will burn up. But that’s ok; it’s all part of the plan. NASA’s probe will collect information on the Sun’s corona. The information to be gathered and beamed back to Earth is important to our understanding of solar processes.

The probe will make 24 orbits of the Sun over seven years. In its final seven orbits the probe will swing out past Venus and then slingshot back in towards the Sun to descend further through the heat of the Sun’s corona on each of its final orbits. Eventually it will pass within 3.8 million miles of the Sun’s surface.

The corona is the upper layer of the Sun’s atmosphere, extending millions of miles beyond the visible surface of the Sun, the photosphere. Photons released by nuclear fusion deep in the interior of the Sun are emitted by the photosphere, giving light. The corona lies millions of miles above this but is curiously hotter than the Sun’s surface. Solar winds generated in the polar and equatorial regions of the Sun lash out from the corona and send massive amounts of electrically charged particles streaming away from the Sun. These winds and other solar activities are the solar weather which reaches across the 93 million miles between the Earth and the Sun and can cause havoc on Earth. The particles of the solar wind travel at speeds over one million miles per hour and can cover the distance between the Sun and the Earth in about ten days. This is much slower than the light from the Sun which can cover that distance in about eight minutes.

The most visible aspect of the solar winds is the generation of aurora, curtains of glowing colors of light, that appear near the Earth’s magnetic poles. In the northern hemisphere, these displays are often called Northern Lights. They shimmer in the Earth’s upper atmosphere when the particles of the solar wind hit the lines of the Earth’s magnetic field. The strongest of these solar winds can also destroy the electronic capability of satellites. The winds can wipe out power grids on the Earth’s surface plunging cities into blackouts which can last for days. When the bursts of energy that generate the solar winds are detected, warnings can be made so that delicate equipment can be turned off or otherwise protected. Life on Earth is protected from the charged particles of the solar wind by the Earth’s own magnetic field. But astronauts above the Earth, or perhaps on a mission to Mars, or living on the moon, are not protected from the massive stream of charged particles.

The Parker Solar Probe is helping us to develop a deeper understanding of the fundamental processes of the Sun. By studying the data received from the probe, we will be able to better forecast solar weather and protect life and property. This knowledge will also provide important information regarding how to protect astronauts when we go out to build colonies off Earth.

Recently the probe reached a milestone on it mission; it began its second orbit of the sun. Important data has already been sent by the probe and received by NASA scientists. On the second orbit, protected by its 4.5 inch carbon-composite solar shield, the probe will pass within 15 million miles of the Sun’s surface. It will go deeper. With each orbit it will transmit more data on the solar wind, and it will continue to find information related to solar eruptions which accelerate particles dangerous speeds, and will plumb the mystery of why the corona is several 100’s of time hotter than the surface of the Sun. The probe will descend deeper and deeper into the heat to discover the depths of the plasma of the Sun’s corona.

These are the golden apples of the Sun, to gain knowledge, to know, to understand.

The picture is based on NASA imagery.

Information on the Parker Solar Probe found at https://www.nasa.gov/sites/default/files/atoms/files/parkersolarprobe_presskit_august2018_final.pdf .

Golden Apples of the Sun based on collection of Ray Bradbury stories of that name and from W.B. Yeats The Song of Wandering Aengus

(*Just_a_Note) – GIORDANO BRUNO

The most recent lunar eclipse on 20 January 2019 included the sighting of a meteor crashing into the disk of the full moon. The flash of the purported crash was captured by Jose Maria Madiedo, a Spanish astronomer who filmed the eclipse. After he reported it others verified a similar sighting.

On June 18, 1178 a similar sight was seen on a crescent moon. That event was recorded by Gervase of Canterbury, “the upper horn of the new moon seemed to split in two and a flame shot from it. From the midpoint of this division a flaming torch sprang up, spewing out, over a considerable distance, fire, hot coals, and sparks.” The description has been thought to have been the creation of the crater Giordano-Bruno. But that crater is estimated to be at least a million years old. The event seen by the monks is now thought to have been an earthly meteor that happened to be juxtaposed over the moon as it flashed through the sky.

In both these instances an “on-the-moon” survey would answer the question. In either case viewing the moon is a worthwhile past time in summer or winter.

As interesting as these events are, an important aspect of the history of science is caught in the web of the craters of the moon. Giordano-Bruno was an outspoken Italian philosopher in the second half of the 1500s. He was a proponent of an infinite universe (1584) which was at odds with the teaching of the powerful universities and church movements of the time. For his trouble to shake the minds of the youth into new paths of thought he was burned at the stake on February 17, 1600.

Art work based on a photograph of the statue of Giordano Bruno by Ettore Ferrari, in Campo de’ Fiori in Rome. Photograph by David Olivier., Public Domain, https://commons.wikimedia.org/w/index.php?curid=923033.

Meteor Crater

In December of last year Science News reported on the discovery of a crater under the ice in Greenland. It is thought to have been caused by a meteorite nearly a mile wide. It was discovered during a scan of the thickness of the ice in the polar regions. The researchers were drawn to look more closely at the area due to the rounded edge of the ice over the crater.

In 2001 I was taking a commercial flight from California to the east coast. As I often do I took out the airline magazine from the seat back pocket and looked at the map of all the airline’s routes. As my trip took me via Dallas, I realized that the route would take us over Winslow, Arizona. This meant we might be flying over America’s most accessible meteor crater. I asked the flight attendant if she would ask the pilot to let us know if the crater could be seen from the airplane. About half an hour later the pilot announced that if we were to look out the windows on the right side of the plane we could see the crater.

There far below us with a clearly raised edge was an obvious crater in the Arizona desert. It was by no means tiny even at our perspective from thirty-some thousand feet. It was roundish, with a particularly squared-off shape. You could clearly see that it was a depression in the Earth.

Years before I had been there to see the crater, and had taken the opportunity to walk down to the crater’s floor. In 1971 I was driving to California for a stint in the Navy. My route west took me along I-40 which passes the Meteor Crater. I needed a break from the highway, and I was curious about what the crater looked like. It was summer, and it was hot. When I entered the visitors’ center and was purchasing a ticket the man at the counter asked if I was in the military and when I showed him my military ID card he waved me on through. I asked him if I could hike down into the crater. He said that if I wanted to I would have to hurry because it was at least an hour’s hike down and back. As I walked towards the door to the outside he called out to me, “Take plenty of water. And look out for snakes.” Good advice to a down-east boy on his first trip to the desert. The path was over a quarter mile long and rocky and steep. When I finally reached the bottom, I stood on the crater floor and looked up at the rim towering 500 feet above me. It had been windy and hot when I stood on the rim. On the crater floor there was no wind, and it was hotter. I don’t remember as much of the hike down into the crater as much as I remember the hike back out. I didn’t see any snakes, but I kept thinking that I should have carried more water. The path up was a scramble in the loose sand and rocks that easily gave way under my feet. When I reached the rim, I was hot, tired, and thirsty.

But it was a good hike – if only that I could say that I had done it. It’s not something they allow visitors to do anymore and probably with good reason. The crater can be a trap. It was simple to get down into it, but not so easy to get out of.

At over a half mile wide the Arizona crater is impressive in size but it doesn’t even crack the top ten of known impact craters on the surface of the earth. But most of the known craters are not as visible or accessible as the one in Arizona. They are hidden by millennia of erosion or they may be under water. The largest known impact crater is Vredefort crater in South Africa. It is 118 miles across and was created by an impacting celestial body that was approximately 3 to 6 miles across approximately 2 billion years ago. This crater is more than twice the size of the Chicxulub crater which is theorized to have been the finishing blow to the reign of the dinosaurs 66 million years ago. The recently discovered but undated crater under the Greenland ice sheet is 19 miles wide. Another crater in Greenland reported in 2012 in Space.com is estimated to be three billion years old and the oldest known impact site on Earth.

But back to Arizona. In the early 1900’s attempts were made to find the meteorite that crashed in to what is now the Painted Desert of Arizona. The object is estimated to have been up to 300,000 tons. The mass of the meteor and its speed likely caused the meteor to vaporize in its explosive impact. When you are on the rim of the crater its not hard to look up and imagine what the object might have looked like as it streaked across the sky and then exploded just before impact, carving out the crater. Soil and plants and rocks and rubble were heaved upward and outwards.

In 1994 I was again standing on the rim of the Arizona crater. I could look up and imagine the bright light that suddenly appeared in the sky and with a thunderous roar exploded in front of me. Of course if I had been standing there 50,000-some years ago I would have been vaporized as well. What is a safe distance from such a blast? Miles and miles I am sure. And even if I was at such a distance to only feel the earth tremble and to see the blinding flash on the horizon and to have been knocked to my knees by the pressure wave from the explosion, I am sure that it would have left a searing mark on my memory. The mark I carry now is one of looking up from the crater floor towards the rim and realizing that the best path for me to take was upward and out before the night fell. And I was wishing I had brought more water.

Information on the craters mentioned above may be found at:

Regarding the Vredefort site, https://geology.com/articles/vredefort-dome.shtml

The recently found crater in Greenland was reported in the December 8, 2018 Science News, https://www.sciencenews.org/article/impact-crater-greenland-asteroid-younger-dryas

In 2012 Space.com reported on what is the oldest known impact site on Earth, https://www.space.com/16366-oldest-meteorite-crater-earth-found.html

The home page of the Arizona Meteor Crater is https://www.meteorcrater.com/

Le Grand Kilogram

“The world is changed.” – opening narrative, “The Lord of the Rings: The Fellowship of the Ring”

The international kilogram mass, or Le Grand K, will no longer the world’s standard. There will no longer be a physical object protected from human touch and wayward air currents under triple bell jars. Now the standard mass for the kilogram will be defined as something ethereal.

I think the first time I heard about “Le Grand K I was in 3^rd grade. An article in my Weekly Reader spoke of a weight stored in a vault outside of Paris. I was fascinated! Since the time I was small, I had seen weights used on scales at feed stores and general stores in old rural North Carolina. They were handled by hardy men and women as they talked about the weather and their families. They moved them onto and off the scale-balance with careless ease as they weighted out feed or flour or nails. But this weight in Paris was completely different. This was a piece of metal that had been carefully made and even more carefully protected. It defined, for all other weights in the world, what a true kilogram actually was. It was handled not with bare, sweaty hands but only with gloved hands. It was covered in a glass bell jar. That bell jar was covered by another, larger glass bell jar. And that bell jar was covered by a larger, third bell jar. Le Grand K did not hang on a nail on the wall next to the scale. It was in a vault, kept behind closed and locked doors.

But over the years corrosion and dust and decay have affected the weight of this world standard. There had to be a better way. So now, all these years later, the old metal standard is just a museum piece. Perhaps if I wander far enough I may find it in a flea market in some distant corner of Europe. It is now detritus of a past age.

There is no longer a physical presence of a defining Kilogram. There is no more tactile experience of grasping the bell jar and lifting it away, being careful not to hit the precious mass. There is no more grasping the mass with gloved hands or padded tongs and feeling the weight of that mass pulling against bone and sinew and muscle of the hand and arm. Now it is ghostly. Now there is an ethereal determination of the pull of something that we cannot readily see as we would the weight.

The device now used to determine the mass of the test object measures electricity. For the test object, the question, “How much does this weigh?” is answered in a vacuum with the soft vibrations of electrical current and the resistance and magnetism of a conductor. There are two forces to be measured. The first is a measurement of value of an applied electrical current in a conductive coil in a Watt-Balance. The second is a measurement of induced voltage in the coil while moving through a stationary magnetic field.

Each of the measurements can be converted into the units of power (watts) by a known and proven mathematical formula, hence the name of the device, the Watt-Balance. The mass to be measured is placed in a pan which pulls down against the stiffness of a conductive, metal coil. A current is applied to the coil. This current stiffens the coil until the upward force in the coil balances the downward pull of the mass being measured. The value of the current required to balance the mass is recorded. The current is then turned off, the subject mass is removed, and the coil is now tested. The coil, a conductor of electric current, is passed through a magnetic field of known strength at carefully controlled, constant velocity. The value of the induced voltage in the coil is recorded. Based on the values of the measured current from the first stage and the value of the induced voltage from the second stage, two mathematical equations can be compared. Through this process the mass of the item being measured can be established with an extremely high degree of accuracy.

The Washington Post article on the redefined kilogram may be found at https://www.washingtonpost.com/science/a-massive-change-nations-will-vote-to-redefine-the-kilogram/2018/11/15/b5704b0a-e6c7-11e8-b8dc-66cca409c180_story.html

The National Institute of Standards and Technology (NIST) information on the Watt-Balance (Kibble-Balance) may be found at https://www.nist.gov/si-redefinition/kilogram-kibble-balance

(*Just_A_Note) – Chang’e-4 cotton seed sprout

On Tuesday January 15, 2019 the China News Agency, Xinhua, reported that the Chnag’e-4 experiment of growing plants on the moon had ended. Seeds of cotton, rape seed, and potato cuttings as well as eggs of the fruit fly had been carried to the moon in the recent landing of Chang’e-4. They were part of an experiment to see if terrestrial plants could be coaxed to grow in an enclosed and protected environment on the surface of the moon. The experiment was enclosed in a heated canister. Sunlight to stimulate plant growth was directed into the canister through a tube. Cameras were included in the canister to record the plant growth. Within days of the landing on the far side of the moon, the world was excited to learn that one of the cotton seeds had sprouted and its small stalk was the first plant to be cultivated on the moon’s surface. However, it was the only plant in the experiment to germinate and grow. The plant did not fully develop. Now that the lunar night, during which the dark side will not receive sunlight, has begun in the current phase of the moon, the experiment has been terminated.

The full article may be found at http://www.xinhuanet.com/english/2019-01/15/c_137745505.htm

(Just_A_Note) postings are short articles regarding current, noteworthy events in science and being outdoors.