Finally watching ISS

Hi,
today I am finally going to write about my first experience watching ISS, the International Space Station. I have probably seen it before it is just that I did not realize that it is not an airplane.


ISS is a space station (biggest that humanity has) orbiting around 400 kilometers above the sea level. There is lot of interesting stuff about it but in this post, we are going to concern ourselves only with the very simple part, just seeing it.

Do not get too cocky. With naked eye, it will look like a bright star, around the magnitude of Venus at its best. It moves fast and even the best flights above your place will take maximum of about 6 minutes. From my experience, simple binoculars do not make much of a difference, though telescope could and I am yet to see how it will work out with good one, for example if I am able to track it.

Now it might not seem as much but remember, you are seeing the ISS, 150 billion $ project! The upside of it is that the station passes everyday above your place. It will always happen at sunset or sunrise, that is because the station must be sunlit but you have to be already in the shadow of Earth.

Most internet sites will recommend you the NASA webpage but it is horribly done and I will rather link to this one: http://iss.astroviewer.net/observation.php

In the case you are the type of person who uses smart phone, you can also download some app like ISS tracker.

Dragallur

Note: even though ISS will pass over 95% of the world population it has over every place pauses for many days. This is because the Earth is rotating under it and it takes some time before it comes to “phase” again.

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Tupper’s self referential formula not so referential after all

Hi,
Since the point I found about the Heart equation, which is just an equation that when you plot shows the shape of heart, I was wondering what type of pictures one could create using just math symbols. Of course, when you have function you are quite limited since there cannot be two x’s above each other. In equation, it is better since you are not limited by this but functions like logarithm or sinus are not made for drawing pictures, usually just curves. I thought that anything more complicated would be basically impossible to figure out, until I found the Tupper’s self-referential formula.

It is just completely “epic” and here is how it looks:Tupper's self referential formula plot.svg

There are two things that you might have noticed. It is a plot, that is quite simple and yeah, this formula plots itself. When I first saw I could not believe my eyes though later I found out that it is quite fake.

What you see up there is plotted function but not smoothly, rather using the mod function and bunch of rounding to get actual pixels. This is quite cool idea. You can notice one more thing, there is no number specified on the y-axis. Therefore, the function loses some of its uniqueness.

The role of this function is to convert bitmap aka picture of the size 17×106 to constant k. For this special case k is very big number, this one:

960 939 379 918 958 884 971 672 962 127 852 754 715 004 339 660 129 306 651 505 519 271 702 802 395 266 424 689 642 842 174 350 718 121 267 153 782 770 623 355 993 237 280 874 144 307 891 325 963 941 337 723 487 857 735 749 823 926 629 715 517 173 716 995 165 232 890 538 221 612 403 238 855 866 184 013 235 585 136 048 828 693 337 902 491 454 229 288 667 081 096 184 496 091 705 183 454 067 827 731 551 705 405 381 627 380 967 602 565 625 016 981 482 083 418 783 163 849 115 590 225 610 003 652 351 370 343 874 461 848 378 737 238 198 224 849 863 465 033 159 410 054 974 700 593 138 339 226 497 249 461 751 545 728 366 702 369 745 461 014 655 997 933 798 537 483 143 786 841 806 593 422 227 898 388 722 980 000 748 404 719

If you use the number in some internet program it will be reversed, so that is why the axis on the picture are reversed. Since the formula maps all possible bitmaps of the size mentioned, it is just extremely long graph containing every possible option, even itself. This is interesting in its own way though it is not anymore very “self-referential”, it is like if you would make a program creating all possibilities of 10000 characters long string. It would also contain the code itself though there is nothing special about it.

Click here to see the beginning of the graph.

Dragallur

Picture source: By Larske – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=22421657

Taking closer look on Sun

Hi,
today I will write about a unique mission that will go closer to the Sun than ever before (2018).


Something like 3.9 million miles will be the closest approach (should I rant about the imperial units or just convert them?). This means going through the Sun’s corona, that is the legendary region that is apparently not quite well explained, meaning, we do not know why is it hotter than the surface of the Sun, but I am no expert on that.

It is caller Parker Solar Probe, I am thinking that they named it after Matt Parker and the Parker square (anybody?). There are going to be top grade instruments on the board and these need to be carefully protected, aka. when you put 11.5 cm of carbon-composite “desk” around it, it will work.

This thing is going to be fast in its top speed, like 194 km/s, yeah that’s per second which is crazy fast. That would be less than 2 seconds to get from my home to Berlin, fun, I guess it would take some time to accelerate me to that speed (unless my life did not matter).

Another interesting thing that has an effect here and that I mentioned in other post, is that it is hard to hit the Sun since the Earth is traveling very quickly around and just because you get out of its atmosphere does not mean that you fall towards the center of its orbit. Parker Probe will use Venus to slow down to get there without such effort.

Dragallur

Lovely Jupiter

Hi,
today I want to do a short rewrite of some posts from NASA page about things happening lately in space, simply to understand and remember them better, makes sense huh?


I have got three things, Van Allen Probes, OSIRIS-REx and Juno (I am saving that one as last since it is simply best).

Van Allen Probes are two satellites orbiting Earth in 9 hour intervals (2 000 miles per second). They celebrated their 5th year anniversary. Such a satellite must be hardened against radiation, otherwise the high energetic particles would destroy its electronics. Throughout its life, it discovered for example that there can be 3rd radiation belt around the Earth.

I already wrote about OSIRIS-Rex before. It is rare mission, first of its kind because it will optimally return samples of the asteroid Bennu back to Earth. On September 22nd, it will pass couple thousand kilometers above Earth that will speed it up so that it does not have to use so much fuel. They had to make sure that the spacecraft does not hit some other satellite that is in the Earth’s orbit, it would be quite sad if this couple hundred-million-dollar project failed even before the landing (I guess it must be in this magnitude).

If you read my blog you know about the spacecraft Juno and that it got close to Jupiter (and started the mission after the long flight). I guess I do not need to say anything when I share those (color enhanced) pictures from the eight-close approach.Juno’s Eighth Close Approach to Jupiter

Dragallur

Sources are just those three NASA pages.

Why do I change my mind?

Hi,
I was just writing a post about Spiral dynamics and searching some resources to quote certain important bits and remind myself of things that I forgot (Spiral dynamics is a conceptual framework describing the evolution of society as well as individual). Since it is not a main stream school of thought I tried to find some criticism of it. After reading (only one) article I remembered something very interesting, why do I always change my opinion after a single piece of new evidence supporting the other side appears?


I remember very well (and I am not proud of it) how before I knew much about conspiracy theories every single piece of evidence was able to change my point of view, it got absurd after couple of times and now I have to stop and think about why is this so, why when I read about veganism let’s say (completely random), I do find why you lower your greenhouse gas emission but then in a single evidence, or even just an anecdotal saying I am back where I started. After I read exactly about the issue I go back again and again… back and forth it goes.

When I think about it I can clearly see first reason right off the back. If I do not know much about the topic before I cannot even decide what seems right and what not, I cannot simply filter out most of the crap. Also, I take an opinion after first piece of evidence and that surprises me, I could just as well hold back some time and not be surprised as much immediately. Last point is that most information, about conspiracy theory for example I take from the internet. This is very important because internet will always argue with two sides and it is just about the way that you write your question, this way you can manipulate yourself very easily (confirmation bias). In simple issues, you might find out very quickly that there are not many arguments for one side and those that exist were debunked hundreds of times.

When something is more complicated it is important to take some time.

Dragallur

Swap the numbers

Hi,
I am reading a book from Matt Parker now. It is called “Things to make and do in the fourth dimension” and the ~200 pages that I read are quiet amazing. The author is also YouTuber and it seems that he mostly does “Standupmaths” which is cool channel. I got inspired a bit and created this game that I started to call “Swap the numbers”.


I was thinking about battery on my phone and how it is going down and that it would be interesting, if the first and second number swapped with the first after subtraction of 1,2 or 3 or more percent at a time. I wrote down bunch sequences, beginning with 100 and going down by one digit numbers.

It is not finished since I want to find a way to predict how these sequences form and I have not figured it out yet. I will give an example and then show why this game is so peculiar.

Let’s say that we subtract the number four, that is the one that I started with:

100 (subtract four) 96 (swap both digits) 69 (subtract four) 65 (and so on…) 56 52 25 21 12 8 80 76 67 63 36 32 23 19 91 87 78 74 47 43 34 30 3 -1 10 6 60 56 65 61 16 12 21 17 71 67 76 72 27 23 32 28 82 78 87 83 38 34 43 39 93 89 98 94 49 45 54 50 5 1 10 6 60 56

If you quickly go through these numbers you will find out that they repeat. When the “10” appears for the second time it starts to repeat. (I also forgot to say that if there is negative number it will act as positive on the “swap” step.) For some reason, many of these “constants” that I start with, end in lapses of “tens” meaning that after “-1” there is “10” and then that is the cycle until new “10” appears. First few numbers have the length of the cycle or lapse “36” or “12” and so far, there seems to be only “1 and 10” as constants that will pull it down to zero. (Also 100 but that is trivial and I have not checked some that could be obvious.)

I have made a program in Delphi 7 to write for me all the numbers for any given constant, that is useful but I will still have to consider the mechanism itself to start to understand it.

Dragallur

I have 420 likes on FB and it is completely useless

Hi,
so today I reached 420 likes on my Facebook page. Page that connects directly to this blog. That is almost two times as many followers on the blog itself, after more than two years that is certainly not much but I am surprised how I got those likes on Facebook and how pointless they are anyway.

420

It says that I will soon reach 500 and that I should give them money so that I reach it sooner.


Since I do not post very often here, I am not preparing the posts very long time (like today), I do not get many more followers on WordPress. Most of the views come from some searches on Google and somehow people tend to be very interested in this post because it has about 7 or 8 times as much views as any other one, exactly 1,066 as of 17.7.2017. I guess most schools in USA learn about HClO4 and HClO in winter and that is why I have most views in that time of year even though it was such a long time since I wrote the post.
So, I have got 420 likes and it is completely useless. Why? Because when I share something on the page most people do not even see it on their “walls” (yes, I have an option to “market” my post for money so that more people see it which is completely absurd). Anyway 420 is a number that has something to do with cannabis and it is 42 times 10 which is nice.
420 is these numbers multiplied together: 2;2;3;5;7. Those can be accidentally also written like this:
a_0=2
a_n=a_(n-1)+ceil((ceil(√(n-1.5))^2)/3)
That took me at least half an hour to come up with. The function “ceil” takes the number and rounds it up. I hope it creates the numbers correctly. Well that reminds me that you can create a game from this. I am going to do that in school. Just pick few numbers and then try to write either sequence or equation that fits it. That is actually quite endless game with lot of possibilities and variations. Maybe one could say that they will use only exponents for example though I think that it is much easier with all those other fancy functions that make the numbers “nice” like rounding up.
Well I might try another number another day.
Dragallur

Why are cells so small?

Hi,
ever wondered why you have to use microscope to see cell? Well cells are small but why?

There is a simple geometrical reason for it and it has to do with volume and surface area. First let’s take the case of cell being very big and what it would mean for it.

Such a cell would have much greater volume because of greater diameter, that is quite logical, but if you compare it to the surface area (which also increased) the ratio between the two attributes increased, meaning surface area did not grow so much as volume.

Volume (no matter the shape) grows rapidly with the function d^3 where d is the diameter [1]. On the other hand, the surface area only with d^2. So, what this means for the cell is that the surface = the membranes, are going to need to work extra hard to feed and clean up the rest of the big cell. This has some limit and that is why cells tend to be rather small and only viewable with microscope.

If the diameter is 1 than both volume and area are 1. (ratio 1/1=1)
If the diameter is 3 than volume is 27 and area 9. (ratio 27/9=3)
If the diameter is 5 than volume is 125 and area 25 (ratio 125/5=5)

The cell also cannot be too small otherwise the “equipment” (organelles) would not fit in.

Dragallur

Source: https://www.youtube.com/watch?v=wuXSEOKNxN8

[1] Take a cube for example the equation for its volume is V=a^3 where a is the side.

How slow can slow motion get?

Hi,
ever been wondering how slow can slow motion get? If you hang for a longer time on YouTube eventually you might notice the channel The Slow Mo Guys or Smarter Every Day, both of them feature „quite often“ slow motion videos, meaning videos that have many frames per second (FPS). If you then slow the frames down you will get very slow video showing detail of whatever you are filming, whether it is flame tornado or AK-47 under water.


The slowest I ever watched is this one: https://www.youtube.com/watch?v=xbuvcQrAOSk

It has FPS of 343 915. That is a lot and in the video they are cracking glass container with high temperature difference. The video is so dark because in the short amount of time, not much light can get into the camera and that is often the limit for such high speed filming. You can also see that even though the video is so slow, the crack still propagates through the glass in surprising speed.

MovieBut this is not the limit, you can go much slower but it requires whole different technique. With 1 trillion FPS you can actually see light traveling through medium, it looks pretty impressive but how can it be done?

The scientists use a laser to lighten up what they want to take photo of. They take a 1 dimensional pictures, basically line of pixels[1], couple hundred times and then with a smart mirror they move along the object that they photograph. This technique is called femto-photography and the event on stage has to be performed many times before one gets the picture.

To put it in different words, you take a titanium-sapphire laser. Lighten up the object for a short time. Capture the photons that bounce back to you. Repeat over and over again and with some mathematical reconstruction techniques you got your result:

https://www.youtube.com/watch?v=qRV1em–gaM

Interestingly enough this kind of device is able to see around corners and has very high potential for use in many technical fields if we are able to make it work faster and in smaller devices.

Post based on TED talk.

Dragallur

[1]It is not really line of pixels as you can read in the next paragraph. You are getting back couple of photons and through the mathematical analysing you get the picture.

Gif source. http://web.media.mit.edu/~raskar/trillionfps/

 

How do bearings lower friction?

Hi,
The first time I really encountered object with bearings and was wondering about what they really are was about 3 years back when I was on inline skates with a classmate. There was a nice long and smooth downhill and we both drove down without much beforehand added speed. Soon he was going way faster and was still moving many seconds after me. At that point when we started to talk about it, I thought than my inline skates do not have any ball bearings, which I now think is not true, he only had clean ones since his skates were new. Probably without bearings the skates would not work.


Ball bearing. See how they do not slide, they rotate.

Ball bearings are small balls (often from metal) enclosed between two spaces that are supposed to rotate, for example on some axis. It is possible to just leave the two surfaces touching but then they just rub against each other which causes high friction. The important part is that the balls as you can see on the left, rotate, they do not slide and when circular object is only rotating instead of sliding it does not experience much of a resistance. Try it yourself. Take a pencil and toss it across table so that it does not start to turn (parallel with the direction of the movement). Remember the distance where it got and try the same thing but this time perpendicularly and see how far it gets, that is exactly what the bearings are doing.

There are lot of types made for different purposes. Since the bearings have much lower area with which they are touching they do not distribute pressure so well, also they might need cleaning often or lubrication. In fidget spinners you will of course find bearings. The ones that spin very long time are the ones with ceramic bearings.

Dragallur