If Earth’s rotation speed changed, what would happen?

A billion years ago a year was 385 Earth days, too. So the days were shorter and the years were longer.

Over time Earth rotation slows down and we have to add time to the clock. When we do that the time we add are called “leap seconds.” This takes place at midnight UTC time where they have a 61 second minute in order to coordinate world clocks with the ever slowing rotation of Earth. This happened December 31, 2016 at 23:59:60. Notice that 23:59:59 should click over to 00:00:00, but in this case an extra second was added and the time became 23:59:60 before it clicked over. All leap seconds are added either June 30 or December 31.

This happens only occasionally. Nothing to worry about.

How do autonomous cars know which signs apply to them (i.e. how to map signs to their side of their side of the road and/or lane)?

Amazing, huh. Do you own an Android Phone? There is an app called Google Translate. If you point the phone at a sign in a foreign language, it will show you the sign in your language.

We’ve come a long way with sign recognition!

Spaceships and Hollywood

Spock and Kirk
First officer Spock (left) and Captain Kirk on the Starship Enterprise didn’t float inside their spaceship because of “artificial gravity.”

Spoiler alert – in the future there never will be artificial gravity – astronauts won’t be able to walk around in spaceships.

In the movies most spaceships like the Starship Enterprise employ a convenient technology they call “artificial gravity” to overcome this weightlessness problem. In a few movies they even rotate parts of the ship, though the part of the ship that rotates often has no relevance to the part of the space ship people are walking around in.

No matter. Walking around is a convenient way to avoid a big budget.

Battle-Spaceship - gravity inside will not exist
This battle-spaceship shows not even an attempt to justify how people inside seem to have no problem walking around.

Weightlessness is a pesky little problem and we’ve become comfortable accepting that on spaceships of the future you’ll be solidly on the floor. Venture outside to fix anything and you’ll be weightless maybe (unless you use something they call “gravity boots”) but inside, put something on a table and it stays on the table. People won’t be weightless in spaceships in the future.

That’s why they call this stuff science fiction. There won’t be any artificial gravity and to the dismay of Kirk and Spock a spaceship that looks like their’s will have weightless people inside.

Von Braun Spacewheel
The Von Braun Spacewheel is the only design occupants could have “artificial gravity” via centripetal acceleration.

Another design, a real design, for a spaceship that would actually have “artificial gravity” is called the Von Braun spacewheel, and envisioned in movies wanting more realism. The Von Braun spacewheel looks like this contraption. Of course, it spins and as it does the occupants inside experience centripetal acceleration, also sometimes known as artificial gravity.

So why doesn’t NASA build one of these?

Well, along comes the real world, pushing Hollywood right outta there.

  1. They don’t have the lifting power to get all the parts up there. It’s doubtful the Falcon-heavy will be utilized for such a project.
  2. Assembly and then pressuring it inside are formidable obstacles. This is not impossible, but beyond available budgets.
  3. Zero gravity laboratories, like the present International Space Station have taught us that research in microgravity environments is valuable.
  4. With exercise, astronauts do just fine, so why bother?

Alas, we may send people to Mars one day, but those poor ol’ chaps will be weightless all the way, and exercise like they do on the ISS.

Are we about to hit maximum technological achievements or will we keep going further at a steady pace? Or are we about to run out of improvements?

Did you know once in history it was decided that everything that ever will be invented has already been invented? It’s true.

Charles H. Duell was the Commissioner of US patent office in 1899. Mr. Deull’s most famous attributed utterance is that ‘everything that can be invented has been invented.’ Most patent attorneys have also heard that the quote is apocryphal.” Quoted here.

That being said, they said it at the end of the nineteenth century, they will say it again! But alas, more things and technology will come along – not at a “stead” pace, as you ask, but in jerks, leaps and bounds, stalls and stumbles!

Why I switched from OpenSUSE Tumbleweed to Kubuntu to Fedora

I’ve been doing this awhile – installing Linux on my computer is my hobby. By “awhile” I mean I first started using Linux back in the 1990s. I ran RedHat Linux before it went public!

Let me tell you about my journey from stable point releases to full-rolling distros back to point to point distros and now to Fedora.

Everybody, and I do mean everybody in the Linux world has a million opinions about which Linux OS or desktop environment is best. You can see people arguing this stuff intensely online! I have no intention to try to convince you which Linux to run. I’ve run a lot of them over the years. No sense in naming them.

For stability, I settled on “point to point” distros for years. These included Linux Mint, Ubuntu, Fedora, OpenSUSE Leap – the list will go on and on, trust me.

The problem is that most of these require you to do a reinstall of the OS when there comes along a major upgrade every six or twelve months or so.

It occurred to me, then to move from Ubuntu Studio (which I was using a year ago) to something completely different. I went with Manjaro Linux, a rolling distribution based on Arch. From there I went to Antergos and stayed there a long time.

Then I switched, just to be different, and went with OpenSUSE Tumbleweed, a rolling distribution that worked great for me. I used it for an exceptionally long time – a few months I believe.

Now, as a Linux hobbyist, I’m always fiddling, and I can’t tell you how many times I’ve broken my Linux and had to reinstall! What ultimately happened, though, is that my Tumbleweed system broke all by itself with just a simple upgrade. Then it happened two or three more times and I got frustrated. OpenSUSE Tumbleweed began to look unstable and frustrating to me.opensuse_tumbleweed_01

Said I to my wife (who tolerates me – she runs Windows on her computer), “That’s the problem with rolling distributions. I’m going back to something more stable.

So I went with Kubuntu and was very happy for a long time.kubuntu

After some time, however, I did start to notice that online videos from sources like YouTube, Netflix and Amazon, started to get “choppy,” which was very annoying. I reinstalled and it fixed it, but not completely. You could still detect a slight jerk in the video every 5 seconds. Oh how annoying that became. On top of that I started thinking about that selling point of the rolling distros: “Once you install a rolling distribution of Linux you will never have to reinstall it again.”

Well, I know that’s not completely true, because it can break, but it’s still a good selling point.

Then I started thinking about Fedora, the upstream distribution to RedHat Linux (a commercial version of Linux).

Fedora-Core-400x270

Fedora is a point to point distribution. There are minor security system and other updates, but the base system changes once every six months. And…. get this… you don’t have to reinstall to upgrade from Fedora 27 to Fedora 28 (for example). The whole thing can be upgraded simply from a command line interface.

So here I am. Fedora. (Also I’m using KDE these days, but that’s another journey to tell you about sometime.)

And guess what? The “jerking” of the videos? It doesn’t happen anymore! I didn’t expect that, but my video experience has improved many times over.

Of course, learning things like “dnf” instead of “apt-get” and getting things like kdenlive or ffmpeg working for me took some fiddling, but nothing too difficult and always easy to find help online.

That’s why I’m now using Fedora.

Magic Card trick attempt #2

In the first example, you saw how a card was magically removed from a group of cards. Let’s try that again.

Here is another group of cards. Mentally pick one card but DO NOT CLICK on the card. Clicking does NO good. Just carefully memorize the card you have chosen!

Screenshot_20180130_181630

Say the name of the card ALOUD several times. When you are ready then prepare to have your mind blown!

CLICK HERE to CONTINUE

Linux Software: the GIMP

Although it started as a Linux program, you can now download the opensource program GIMP for Windows and Mac.

While experimenting with the GIMP (I’m an old hat with it – I love it) I created the image below. I’m thinking of using it (with altered writing on the blackboard, for my articles about Linux in the future!)

todays-lesson-install-fonts