Generation Y

Reina Street in Central Havana. (14ymedio)

Generation Y is a blog from Havana, Cuba, written by Yoani Sanchez. I would say that her writing is exceptional, except that I think she is writing in Spanish and someone else is translating it. In that case we would have to give at least half credit to the translator. Whatever. In any case she is writing about life in Cuba and what she writes is pretty wonderful. She hasn't been arrested so far. So, plus one for writing skill.

Knowledge

There are two kinds of knowledge (at least). One is what's in your head, everything you know and / or believe, everything your senses are telling you, all your thoughts, all knitted together into one complex whole. It's what we use to make decisions, to run our lives.
    Another kind of knowledge are factoids, small bits of knowledge about one specific thing. These can be communicated to other people, they are small and simple enough that they can be explained in a finite amount of time. They can also be stuck together to build bigger things, like ideas, plans and concepts. The are kind of like Legos (the small, plastic, toy building blocks) or bricks. You can stack them up and make things. They are also kind of like blueprints or plans. They can be used to guide the construction of some sort of thing.
     Not all of this knowledge is true. Just as if you build a house out bricks made of dung, a belief system built on bullshit is liable to collapse.

    Science is built on factoids, factoids that get tested. Some of them are found to be true and are kept. Some are found to be false and are thrown out. Some are true for a while, and then later on are found to be false, so we keep them around for a while, but when we find out the truth, we throw them out.
    I suspect that a  lot of religion is made up of stories to explain stuff that confused people, stuff for which we had no direct evidence. Stories are like strings of popcorn, where each popped kernel is a factoid, each of which may be true, or not. People's beliefs are based on the stories they have been told. While many religious beliefs are benign, some are not, and some only reveal their true character when pressure is applied.     Killing people, for instance, is one of those issues. Some people think you should never kill anyone. Some people think they should kill everyone who is different in some specific way. Some people think there are times when killing is justified. I would like to think that if we could just show all the wrong-thinking people the error of their ways, they would reform, and start believing and behaving correctly. Unfortunately, I don't think there is enough time in the universe to do that. Lunatics seem to popping up with ever increasing frequency, kind of like if the dead were coming out of their graves. Is it just a fluke that Zombie movies and games are all the rage these days? I don't think so.

Super Pressure Balloon

Super Pressure balloon shortly before release. Note the yellow machine on the ground.

While reading about some NASA balloon projects, I came across this picture of the launch of a balloon from an airport in New Zealand. I thought it gave a pretty good idea of the size of the thing.

Super Pressure balloon being inflated. Now you can see how big that machine is.

Especially when you find out that the little bitty yellow device on the ground in the top picture is actually a giant frigging 80 ton crane.

Super Pressure Balloon's route around the bottom of the world.

This was a Super Pressure balloon, designed to maintain a constant altitude for days on end. This one managed to stay aloft for a month before a leak prompted them to bring it down in Australia.
     Most high altitude balloons are zero pressure - the pressure of the helium inside is the same as the air outside. During the day the balloon warms up, the helium expands and the balloon goes up. During the night, it cools off, contracts and the balloon loses altitude. With a Super Pressure balloon, the volume is fixed. It stays the same day and night. Since the volume doesn't change, the altitude doesn't change, at least not as much as a conventional balloon. These things are flying around at an altitude of about 25 miles, three times as high as your typical jetliner.
    I suspect the term 'Super Pressure' is a bit of a misnomer. I suspect you would be hard pressed to be able to measure the pressure in the balloon when it is at altitude. Since there is almost no air at that height, it wouldn't take much to keep the balloon inflated. Just how much pressure? At 33.5 kilometers, which was this balloon's nominal altitude, the atmospheric air pressure is about 19 millibars, so one millibar of pressure is probably enough to keep this thing happy. (Ground level air pressure is around 1,000 millibars.)

Fun with Chromebook

Not. Little problems keep cropping up. I used to complain about them on the Google Help Forum, but evidently that it not the proper place to voice your complaints as a couple 'experts' got their knickers all in a twist. So I Googled and found there is specific jobbie for 'feedback'. Google claims they read them all, but who knows? It might just all go in the bit-bucket. Whatever, gives me a place to vent. Here's my latest:

The 'Find' text (Control-F) function is being stupid. Open it on one tab (web page) and enter your text and it will find it, or not. Go to another tab/page and you get no response. Used to be it would tell you if your search term was there or not. Now it just sits there looking stupid. Only when you erase the text and re-enter it does it wake up and fly right.

Cookies For All

This message now appears at the top of this blog when you access it from Europe:
This site uses cookies from Google to deliver its services, to personalize ads and to analyze traffic. Information about your use of this site is shared with Google. By using this site, you agree to its use of cookies.
The European Union now requires 'cookie' warning messages on all web pages that can be accessed from Europe. I don't know whether to be upset, offended, or relieved. Relieved because Google (the beneficent) provided the message for free. I didn't even have to think about it. Upset because this sounds like more stupid government meddling. Offended because - how dare they interfere with the free dissemination and collection of important information. I mean, I need to know your shoe size.

I'm not going to worry about it too much. The internet is a haphazard collection of protocols and rules, and we are just beginning to sort out all the implications of what we have created. There are going to be hiccups but I am confident we will figure it out, eventually. It may take a few years (decades? centuries?) but we'll get there. Of course there are always going to be people, to use the term loosely, who will attempt to strangle the 'net in order to promote their twisted view of reality. China, I'm lookin' at you.

Ceres, Part 2

Circling Occator Crater on Ceres (Silent)
The crater is about 60 miles in diameter and about 2 miles deep.
Space probe Dawn has moved closer to Ceres and is now orbiting at an altitude of 900 miles. Dawn has been busy doing what space probes do, which is taking pictures, so we have a better picture of the two white spots that showed up when Dawn arrived here six months ago. Still don't know what they are, but they appear to be near the center of a large impact crater. So once upon a time Ceres got hit with a pretty big rock. A collision like that releases a lot of energy in the form of heat, possibly enough to liquefy rock and shoot a stream back out into space. But what is the white stuff? It could be ice, but water ice would sublimate (evaporate), so you would need a pretty good size deposit for it to survive how many millions (billions?) of years since the big crunch. It could be some other kind of ice, but you still have the same problem. If it is some kind of solid, how has it managed to not become mixed in with the surrounding rock? We find mineral deposits on the Earth that are relatively pure. The only one I can think of that would be white is salt, and for some reason that seems unlikely. I guess I've never heard anyone suggest that they had found salt anyplace outside of Earth.

Part 1 here.

Spacecraft

Kennedy Space Center, Florida, Feb. 2, 2015. Charles Bolden delivers a “state of the agency” address. Left to right, the three spacecraft on display are the Boeing CST-100, NASA's Orion and the SpaceX Dragon. Photo: NASA/Amber Watson

Typical NASA, the didn't identify the spacecraft in their photo. I had to figure that for myself. Stack Exchange provided an answer. The Dragon and Orion have both been to space, though not with any passengers.

This diagram shows the seven pieces of Orion’s primary structure and the order in which they are welded together. Credits: NASA

I came across this photo while I was reading about the welding operation NASA was using to build the Orion. The are going to a great deal of trouble, building one complete shell structure just to check their tools and procedures. A spacecraft is a pressure vessel, and while the pressure is not that high, the spacecraft itself is rather large. I have an air compressor in my garage that holds 100 PSI, but it's only about a foot in diameter. These craft are considerable larger, and while the pressure is lower, when multiplied by the area it gets big, as in tons of force. The shell has to be able to withstand the strain, and it probably doesn't weigh any more than my air compressor.


Robotic Friction Stir Welding Automation - Courtesy of CRIQ
To my surprise, I found they are using friction stir welding, which is kind of a bizarre technique. Watching the way aluminum will gum up a file or a grindstone might give you some idea of why it works.

Update: Jack provided this snippet from a different Wikipedia article:

Friction welding (FRW) is a solid-state welding process that generates heat through mechanical friction between work pieces in relative motion to one another, with the addition of a lateral force called "upset" to plastically displace and fuse the materials. Technically, because no melt occurs, friction welding is not actually a welding process in the traditional sense, but a forging technique

Update November 2020 replaced missing video.