# Sunday, June 27, 2021

Albert Einstein was a genius, who understood the universe in ways that I will never completely grasp. In his book Relativity, he tried to explain his theories of relativity in a way that might make sense to mere mortals like me.

Einstein begins by discussing the concepts of relative position and velocity. The example to which he returns repeatedly is the person on a speeding train and a person on the ground next to the tracks. An object moving forward on the train would have a different velocity relative to each person. The math for this is relatively straightforward. Velocity is distance divided by time, and you can add or subtract vectors when determining relative velocities. However, Einstein posited that the velocity of light is constant (at least in a vacuum), so we must adjust our concept of relative velocities when dealing with light. In the example above, the perceived velocity of light is the same for both persons. To make the math work, we must modify either distance or time or both. This change in distance and time is negligible when dealing with most objects, but it becomes significant when objects approach the speed of light. This is the basis for Einstein's Special Theory of Relativity. A basic principle of this theory is that nothing can exceed the speed of light.

In the second section of the book, Einstein discusses his General Theory of Relativity, which builds on top of Special Relativity. This theory takes into account the effects of fields - particularly gravitational fields. Strong gravitational forces can actually bend the space-time continuum and may explain the physical limits of the universe. The math becomes more complex here and is significant only on a more macro scale.

Einstein concludes by discussing the structure of space itself. The universe appears to be expanding, to have no end, that there is a finite amount of mass and energy in the universe, and to be of approximately the same density everywhere. These three things seem to be inconsistent unless we consider the idea that space is curved on itself, much as a circle is curved on itself in 2 dimensions and a sphere curves on itself in 3 dimensions.  This would allow the universe to be both limitless and unbounded.

Although the book contains a lot of math, it does not include any calculus; so, if you are familiar with algebra and geometry, you can (mostly) follow the mathematics. Einstein builds on the work of scientists who preceded him, such as Newton and Lorentz, so it is helpful to be familiar with their ideas.

Some of the ideas presented herein sound like fudge factors to make the math work; however, a number of experiments were performed shortly after the Special Theory's publication and those experiments supported the theory. Experiments on General Relativity were difficult to perform at that time, but experiments since that time have supported this theory, as well.

This book was written in 1916, well before Albert Einstein became a worldwide household name. Despite its short length, this is not a simple book. But it is far simpler than reading academic papers and mathematical proofs on these topics. And it is a good introduction to ideas that shape our understanding of the universe.

Sunday, June 27, 2021 9:06:00 AM (GMT Daylight Time, UTC+01:00)
# Saturday, June 26, 2021

"All this happened, more or less."

Kurt Vonnegut begins his novel Slaughterhouse-Five with an autobiographical description of the effect that World War II had on him. He witnessed the carpet bombing of Dresden, Germany while he was held there as a prisoner of war. He reflects on how he struggled to describe his wartime experiences and to relate to his friends who had gone through these struggles with him. In the end, he wrote this book about Billy Pilgrim.

"Listen: Billy Pilgrim has come unstuck in time”.

Billy was a soldier, but he wasn't much of a soldier. He was skinny and weak and he had trouble focusing and he was captured by the Germans before he was even issued a gun or boots. Occasionally, Billy became unstuck in time - traveling to the past or the future to experience different periods of his life before returning to the moment when he left.

On one journey to the future, Billy was kidnapped by aliens and transported to the planet Tralfamador, where he was placed in a zoo for the study and entertainment of the local inhabitants. The Tralfamadorians see the universe in four dimensions, which gives them the ability to perceive every moment of the past and present simultaneously. Because of this, they have developed a philosophy that all that has happened or will happen is unchangeable. They accept as their destiny what they are powerless to affect, and they respond with the simple - almost flippant - phrase: "and so it goes." This phrase follows nearly every mention of death in the book.

This is a science fiction story about aliens and distant planets and time travel. But it is also a war story, chronicling the 1945 Allied bombing of Dresden - a campaign that was successful, but yielded no significant advantage to the Allies. Thousands of civilians were killed in a pointless display of force. More correctly, this is an anti-war story, demonstrating the absurdity of armed conflict.

It is possible that Billy's travels between times and between planets occur only in his imagination - a result of Post Traumatic Stress Disorder, brought on by the horrors of the war; but it does not matter whether or not Billy dreams it all - at least not to the reader and maybe not to Billy. Viewing and living his life nonsequentially helps him to perceive the universe as the aliens do and to adapt some of their fatalistic views and better accept death and tragedy.

The book's non-linear narrative and almost complete lack of a plot might be perceived as a weakness. But Vonnegut takes us through a series of episodes that tie together and he does so with a sparse, informal style that makes for a pleasant journey.

Ultimately, the novel is about fate and inevitability and acceptance of the unavoidable. The Tralfamadorians understood the future and accepted their inability to change it. Billy comes to do the same. Even the horrors of war seem predestined. Those fighting the battles have no control over the events that affect their lives, and the Dresden civilians had no reason to suspect they were a target.

And so it goes.

Saturday, June 26, 2021 9:23:00 AM (GMT Daylight Time, UTC+01:00)
# Thursday, June 24, 2021

GCast 112:

Passing parameters to xUnit.net tests with the InlineData attribute [GCAST 112 ]

If you have multiple unit tests with redundant code, it may make sense to create a single test and pass parameters to it. You can do this using the [InlineData] attribute of xUnit.net.

You can find the source code at https://github.com/DavidGiard/XUnitDemo

Thursday, June 24, 2021 9:19:00 AM (GMT Daylight Time, UTC+01:00)
# Monday, June 21, 2021

Episode 666

Hattan Shobokshi on Getting the Most Out of Bash Scripts

Hattan Shobokshi provides guidance on how to manage Bash scripts effectively, from configuration to libraries he has found useful to architectural guidance.

Monday, June 21, 2021 8:15:00 AM (GMT Daylight Time, UTC+01:00)
# Sunday, June 20, 2021

C.S. Lewis concluded his classic Chronicles of Narnia with The Last Battle. It was the last book written and the last story chronologically in the series.

It is centuries after the events of "The Silver Chair", Aslan has not been seen in many years, and Narnia faces a threat from Calormen - the country to the south, whose people worship a malevolent demon named "Tash". Trouble begins when the talking gorilla Shift deceives the people and the talking beasts by falsely claiming that he has been directly communicating with Aslan.

The book contrasts those who worship Tash out of fear and those who worship Aslan out of love. Shift insists that Aslan and Tash are two names for the same being - an absurd notion given their opposite ways of dealing with their disciples. It is a commentary on those who perceive God as a judge whose main purpose is to exact vengeance on man. My perception of God is that He is filled with love for man and wants to save us all.

This book may be the most religious in the series. Lewis explores themes such as loss of faith, false prophets, the afterlife, and end times.

It is obvious that Lewis intended Aslan as a version of Christ in this alternate universe, but Tash's counterpart in our world is less obvious. When I first read this years ago, I wondered if Lewis intended Tash to represent Allah, as the color and diet of the Calormenes suggested they might be Arabs. But, with this reading, I believe that Tash is a stand-in for Satan.

Halfway through the story, Eustace and Jill and called back to Narnia to help right the wrongs committed there. Eventually, the book reunites us with many of the characters from past stories - a delight for readers.

This story is darker than its predecessors, but it still conveys the optimism and hope that permeates all these novels. It was a very good conclusion to an excellent series.

Sunday, June 20, 2021 9:23:00 AM (GMT Daylight Time, UTC+01:00)
# Saturday, June 19, 2021

I am coming near the end of C.S. Lewis's Chronicles of Narnia.

The Silver Chair is the penultimate novel in the series, as I read them in chronological order.

Narnia's benevolent deity Aslan has already told all the Pevensie children that they will not return; but Eustace Scrubb, who was swept along on their last adventure is the protagonist of this story, along with his classmate Jill Pole. The two of them are called to Narnia by Aslan to rescue King Caspian's son, who went missing ten years earlier.

As with so many of Lewis's other works, this one is filled with Biblical allegories and Christian messages. The world below ground ruled by an evil sorceress where the climactic battle takes place suggests Purgatory, if not Hell. It is clear that Lewis blames the lack of morals among Eustace and Jill's school on the school's rejection of God and religion. The school is so secular that neither child even knows the names of Adam and Eve.

Whether you accept Lewis's faith or not, the story is another good one. It is filled with wonderful characters, including the pessimistic, but charming Puddleglum; and with action and adventures and magical creatures.

I am looking forward to wrapping up the series tomorrow.

Saturday, June 19, 2021 9:26:00 AM (GMT Daylight Time, UTC+01:00)
# Thursday, June 17, 2021

GCast 111:

Writing unit tests with xUnit.net

Learn how to use the xUnit.net open source project to create unit tests for your .NET application You can find the source code at https://github.com/DavidGiard/XUnitDemo

Thursday, June 17, 2021 9:04:00 AM (GMT Daylight Time, UTC+01:00)
# Monday, June 14, 2021

Episode 665

Michael Scherotter on Creativity and Technology

Michael Scherotter was trained as an architect. Today, he works as a Technical Project Manager and he still uses his creativity in his job. His passion for drawing helps him to channel his energy to creatively solve technical problems. He offers Career Coaching for technologists and shows them how to use creativity effectively in their careers.


Monday, June 14, 2021 9:00:00 AM (GMT Daylight Time, UTC+01:00)
# Sunday, June 13, 2021

Eustace Scrubb was rude, arrogant, condescending, and skeptical of the stories his cousins Lucy and Edmund Pevensie told of their visits to the magical land of Narnia. His skepticism is challenged when the three children are drawn through the frame of a painting and find themselves on the deck of The Dawn Treader - a ship sailing across the oceans east of Narnia. On the ship, the Pevensies are reunited with their friend Caspian, who is now the Narnian king and is exploring the ocean and searching for seven Lords who years earlier fled Narnia to escape the evil King Miraz.

C.S. Lewis's The Voyage of the Dawn Treader takes the reader along on this voyage.

We experience slave traders, a transmogrification, a giant sea serpent, invisible men, a pond that turns to gold anything that touches it, an ancient wizard, an anthropomorphized star, merpeople, and the edge of the world. The action is nonstop and takes us from conflict to conflict, reminiscent of Homer's Odyssey. As with the other Narnia stories, Lewis moves us from adventure to adventure, while developing and evolving characters in a short space. One of the characters experiences an epiphany and changes from a useless whiner to realize how his actions have hurt others; others rise to their challenges with heroic actions; and Caspian discovers his responsibility as a King.

Aslan makes an occasional appearance to help or advise others in the story, but he stays mainly in the background.

Lewis packs a great deal into such a short story. This is one of the stronger novels in these Chronicles.

Sunday, June 13, 2021 9:37:00 AM (GMT Daylight Time, UTC+01:00)
# Saturday, June 12, 2021

C.S. Lewis's The Lion, the Witch, and the Wardrobe told the story of Lucy, Edmund, Peter, and Susan Pevensie and their adventures in the world of Narnia. Prince Caspian tells of their second visit to this magical land.

A year after returning home from Narnia, the children are waiting for a train when they are suddenly whisked to a strange land. They realize they are back in Narnia, but the area is unfamiliar to them. They come upon the ruins of a castle and eventually conclude that they are at their old home and that many years have passed since they lived there. Due to the time differences between the Narnian world and our world, it is now over a thousand years since their last visit.

Narnia has fallen on hard times: the holy and benevolent lion Aslan has not been seen in centuries, the false king Miraz has ascended the throne through treachery, and talking animals and trees are nowhere to be found. Prince Caspian, the rightful heir to the throne, has used Susan's horn - originally a gift from Aslan and now an ancient artifact - to summon the Pevensies back to Narnia. Together, they attempt to restore goodness to the world.

Once again, Lewis takes the reader into a world that is both magical and believable. This is a story of a world that has fallen from righteousness into wickedness. It is an attempt at redemption for the land, its rulers, and its people. Knowing Lewis's Christian roots, we can assume he was thinking of the rise and fall and rise of God's chosen people in the Old Testament when he wrote this book.

It is an enjoyable story, and it introduces the fearless talking mouse Reepicheep, who is one of my favourite characters in these Chronicles.

Saturday, June 12, 2021 9:17:00 AM (GMT Daylight Time, UTC+01:00)