Tag Archives: homeschool

It’s the end of Time and Space

So that’s it—with the exception of a few odds & ends that didn’t fit into the story, that’s all I got for Time and Space. I’ll tell you, this was even more fun than I thought it would be. I hope you learned a few things. I sure did.

We started with Sumerians, their Base Sixty counting and 24-hour days; Egyptian sundials and waterclocks; Greek units of distance; the Roman calendar; the hourglass; the geocentric universe; the Mideastern astrolabe; the Silk Road; the Chinese compass and Venetian trade routes; Columbus’ discovery of the New World; the race to find longitude; pendulum clocks, chronometers, steam engines, internal combustion engines, the quartz crystal movement, atomic clocks, GPS; and ended with Einstein’s theories. Whew!

What’s next? So many things! I want to turn this series of blog posts into a book. I’m thinking of doing one of those Kickstarter campaigns. The book version of The Western Civ User’s Guide to Time & Space will have the same feel as the blog: lots of bits of information crammed in with lots of lame gags and cartoons. My rough pencil sketches will become finished illustrations. There will be QR codes so you can access links to sources and music while you read it.

Aaaaaaand—in the next couple of weeks I’ll be starting a new Western Civ User’s Guide with a different topic.

Thanks for following this, you weirdos. I can’t even begin to tell you how grateful I am somebody actually reads these posts.

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A warp in the TimeSpace continuum!

Einstein also theorized that really big objects, like planets, warp the TimeSpace continuum around them. The example often used to illustrate this idea is a bowling ball on a trampoline. The bowling ball is so heavy that it makes a big downward bulge in the surface. Then you roll a marble around the edge of the trampoline. The marble feels a pull toward the bowling ball as it circles around the trampoline. A huge object like the Sun is so enormous that it bends TimeSpace around it. Like the marble, planets are pulled toward the Sun as they circle around. Don’t worry—the planets don’t go crashing into the Sun! Why not? Because they’re set in their orbits around it. There’s a balance between the Sun’s gravity (pulling Earth closer) and the Earth’s centrifugal energy (pulling Earth away) as she orbits. This situation has existed for billions of years.
https://nineplanets.org/questions/getting-closer-sun/

Here’s an animation of the solar system traveling through space: https://www.youtube.com/watch?v=zBlAGGzup48

Here are some cartoons.

http://www.astronomy.ohio-state.edu/~pogge/Ast162/Unit5/gps.html

http://www.alternativephysics.org/book/GPSmythology.htm
This one’s a guy drawing on a white board in time-lapse video which I kind of like—https://www.youtube.com/watch?v=awMw0Vv0QBA

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It’s time for Einstein’s General Theory of Relativity!

It seems Time and Space aren’t two separate things after all. They’re 2 parts of one thing: TimeSpace. They’re what’s called a continuum.
(kon-TIN-you-uhm)
1 : a coherent whole characterized as a collection, sequence, or progression of values or elements varying by minute degrees
https://www.merriam-webster.com/dictionary/continuum

The Sweet-Salty continuum

I suppose a piano keyboard could be considered a continuum: lowest note on one end and highest note on the other, with the keys in between playing both low and high. You could draw up a continuum of food—from, say, the sweetest food you ever ate to the saltiest food you ever ate. Where is barbecue—both sweet and salty—on your continuum?

The continuum of TimeSpace has extreme ends, too—one end nothing but time and the other end nothing but space. This is really hard to think about. Time passes on one end but nothing physical is there. There’s physical stuff on the other end but nothing moves because it’s outside the medium of time. We live in the middle. We’re physical beings in a physical world who walk around and grow older and have kids and live our lives while plants sprout, bloom and die and the planets and stars whirl around in space.

(Does any of this remind you of Sunday-school? I mean how the Bible starts: “In the beginning…” and then God creates the universe, the Earth and the heavens, separates day from night. It’s how the Bible explains time and space. Which means God exists outside the TimeSpace continuum, which is too much for my brain to handle.)

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The speed of light!

The speed of light stays the same—186,282 miles per second in a vacuum. It doesn’t change relative to other objects. If you switch on a light in your rocketship while cruising along at 12 parsecs, the light doesn’t travel at 186,282 miles per second plus 12 parsecs. It stays at 186,282 miles per second. This is because light is an electromagnetic wave and has no mass. Signals from a radio station are electromagnetic waves, too. They wouldn’t speed up or slow down if the radio station were moving.

I say ‘in a vacuum’ because outside of a vacuum light’s going to be slowed down by atmosphere: dust particles, car exhaust, hairspray from actors in 1970s sci-fi movies, bird poop, cigar smoke, &c, &c. Beyond Earth’s atmosphere, in outer space, it’s a vacuum.

My vacuum seems to have a lot of dust particles and dog fur in it, so that slows the light down somewhat.

A lightyear is the distance light can travel in a vacuum—at 186,282 miles per second—in one year. Earth-year, that is!

https://www.sciencealert.com/why-is-the-speed-of-light-the-speed-of-light
https://van.physics.illinois.edu/qa/listing.php?id=2605&t=why-constant-speed-of-light
https://www.sciencefocus.com/space/what-is-a-parsec/

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Einstein’s Special Theory of Relativity


As you move faster, time slows down for you. Even though that’s true when you’re riding in a car, the slowdown is so teeny-tiny that it’s not worth measuring. But, if you were to travel to another galaxy at almost the speed of light, time would slow down—for you—to the point where you would age more slowly than your pals back on Earth.

When you got back from your trip, your friends would be old and wrinkly but you’d be ready to graduate from high school.

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Classical Relativity

Believe it or not, we’re coming to the end of The Western Civ User’s Guide to Time & Space. I would be cheating you customers if I didn’t spend a little time talking about TimeSpace.

The name Einstein has come to be shorthand for genius. It’s still difficult to imagine the abstract way he trained his brain to think about time and space. Back in 1905, Albert Einstein published his theories about Relativity. He had 2 theories, a Special and a General Theory. But first, let’s talk about Classical Relativity.

Classical Relativity: everything moves relative to everything else.

If you’re riding in a train going 45 miles per hour and throw a ball from the back of the car to the front, the ball seems to you to travel at 10 mph. To a cow standing in a field watching you throw the ball, the ball is traveling at 55 mph: 45 mph for the train plus 10 mph for the ball.

A speedometer can say we’re driving an automobile at 45 miles per hour, but that 45 mph is the car’s speed relative to the surface of good ol’ Planet Earth. Earth is also spinning around and circling the Sun. The Sun also circles around in the Milky Way, taking us along with him. The Milky Way circles around in the Universe. Even the Universe is moving—it’s expanding. How fast something is moving can only truly be measured as it relates to something else. That’s Classical Relativity.

I once tried talking my way out of a speeding ticket using this concept but the trooper wasn’t buying it. Just kidding! Actually, I started sobbing uncontrollably and he walked away in disgust.

UPDATE: My pal Ross sent this interesting article about how a fighter jet ran into its own bullets (the jet landed safely). It seems air-friction slowed the bullets but the jet’s engines allowed it to speed up. At any rate, probably I should redraw the above cartoon with the kid inside a box car, instead of standing on a flat car. https://arstechnica.com/tech-policy/2019/04/dutch-f-16-takes-cannon-fire-from-itself/?fbclid=IwAR1aIR4z2buoa-58GgXSQGUIlqAji6qFpE0MsXSAqC2gYGi6kUBg4UBYYLg

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Einstein

So atomic clocks saved the day—yay! Satellites are synchronized with each other to nanosecond accuracy. Their signals let our GPSs figure out where we are because even though those satellites are hurtling through space at 17,000 miles per hour, their atomic clocks will always show the correct time, right? Nothing’s gonna interfere with each satellite’s time, nothing! No sir! Not one thing!

Okay, maybe one thing: Einstein.

I can see you loyal-yet-exasperated readers flinging your half-eaten peanut-butter-and-jelly sandwiches across the room and yelling, “Oh, come off it, Manders! Have you finally gone around the bend? Should we have you fitted for a straight-jacket and a drool-cup? What’s Einstein got to do with my global positioning system?”

Listen, and I will tell you all about it.

Feedback loop

A cesium atom oscillates 9,192,631,770 times every second. That never changes.

What does change is the atoms’ energy state. The excited cesium atoms bounce off the detector every time the microwaves hit the same frequency as the atoms’ oscillations. The detector sends a signal to the microwave resonator, so that the microwave frequency is adjusted to sync better with the atoms. This is called a feedback loop. The detector sends a signal, the signal adjusts the microwave frequency, the microwaves excite the atoms, the atoms bounce off the detector, the detector sends a signal, the signal adjusts the microwave frequency, the microwaves excite the atoms…over and over and over. The time between each signal is exactly one second. No gears, no moving parts to oil, nothing mechanical.

That’s it! That’s how the atomic clock works. Thanks for sticking with me for an entire week on this. Finally, we can get on with our lives!

As with my explanation of the liquid crystal display, this is a simplification. I left out a lot of stuff. It’s the idea, the principle, that I was interested in explaining. Luckily for you, here are links to click on if you’d like more exact, in-depth info about atomic clocks.

https://www.livescience.com/32660-how-does-an-atomic-clock-work.html
https://www.timeanddate.com/time/how-do-atomic-clocks-work.html
https://www.gps.gov/applications/timing/


https://science.howstuffworks.com/question40.htm
https://www.fda.gov/radiation-emitting-products/resources-you-radiation-emitting-products/microwave-oven-radiation
https://science.howstuffworks.com/atomic-clock3.htm
https://www.britannica.com/technology/atomic-clock

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Atoms. They’re small.

Here’s something: before I can even begin to figure out how atomic clocks work, it may be helpful to understand what an atom is. An atom is the smallest thing that exists. Anything you can touch is made out of atoms. Lots of ‘em. There is literally nothing physical that’s smaller than an atom.

An atom is made out of subatomic particles, but these can’t be separated so they don’t count as being smaller than a whole atom.* These particles have Greek names (like Aristotle hahajustkidding). In the middle of the atom are neutrons and protons stuck together in a clump, called a nucleus. Around the nucleus are electrons, circling like the moon circles Earth.** The electrons don’t fly away from the nucleus because the neutrons and protons exert a magnetism kind of like gravity.

So, no, I still haven’t figured out how the atomic clock works. This is taking longer than I thought. I’ll be back as soon as have more info. Please continue to hold.

 

https://www.britannica.com/science/atom

*Ms Physics chimes in: “Atomos (Greek) ‘indivisible’ later proved incorrect!” Well, yes, that’s true. I don’t want you kids getting any ideas. Please, if you manage to isolate an atom—DON’T SPLIT IT!

 

 

** Another Western Civ Irregular Jeffrey K takes exception to me comparing an atom’s nucleus to a planet and electrons to orbiting moons. He says “Electrons don’t really orbit like planets– more like moths around a flame (without the usual fatalities). Also electrons are magnetic but the rest is held together by nuclear forces.” I said “So far as I know, nobody’s seen an atom because they’re so teensy.” So he sent me this:

 

https://www.school-for-champions.com/science/atoms_solar_systems.htm#.Xyk9hB17nzI

 

 

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32,768 oscillations per second

When you hit a tuning fork against something it vibrates, giving a specific musical note.

We learned that a digital clock is regulated by measuring how many times a quartz crystal oscillates per second—32,768 times. How does it count all those vibrations so quickly? Here’s how: the crystal is purposely cut with a laser to exactly the size and shape (the shape of a tuning fork) that will produce 32,768 oscillations in a second, then stop.* The electric circuit zaps the crystal with electricity, which makes the crystal vibrate until it returns to its original shape. When the vibrating stops, exactly one second has passed. The stopped vibrations trigger the circuit to move the second hand and give the crystal another zap.

The same principle applies in animated entertainment for children. The mouse hits the cat, who oscillates for a second, then resumes his former shape.

Here’s how a tuning fork works: https://www.youtube.com/watch?v=hW-igtIn3A8

Basics of LC oscillators and their measurement


https://en.wikipedia.org/wiki/Crystal_oscillator

* “Because 32768Hz can be so conveniently divided to give a 1 second pulse, it is a very popular size for it to be cut to. Manufacturers can bang them out and be sure they will sell.” https://www.quora.com/Why-does-Quartz-vibrate-exactly-32768-2-15-times-per-second

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