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The Semi Precious Moon Collection
Saturday, January 16th 2010
Since the Solar System Simulation currently available in Orinetz Orbit Simulator haven't included the moons orbiting the planets ( and the dwarf planet, Pluto ), I had planned to make another Solar System Simulation that include them.
For that purpose, I have collected various things I need to make such simulation such as the Ephemeris and the images of those moons. To look for the images of moons, I initially used Google Image Search by entering the name of each moons in the Solar System. As simple as it might seems, it was not as easy as imagined. The moons in our solar system was named after the name of gods, goddess and creatures from Roman myth. For moons whose names is less popular than the original myth, all image google gave was not the image of that moon. Adding phrases such as jovian moon or jovian satellite didn't help.
Fortunately when I googled "Himalia", I found a page in Jeremy Gardner's website that contain the images of various moons in Solar System. I told him about Orinetz Orbit Simulator and he was kind enough to let me used his images for the simulation. While his images are good in quality, I can't directly use those images to make the simulation. I have to turn those JPEG images into masked PNG images. So far I had finished transforming the images for Earth's Moon, Martian moons, Jovian moons and Saturn's moons.
After I finished transforming those moons images and saw them arranged in my folder, I realize that they look like an arrangement of Semi Precious Stone ( hence the title of this entry, Semi Precious Moons ). The image of Callisto - a Jovian moon - is particularly looks adorable. One of my female friends even said that she wants to wear it as necklace. I don't think her neck is strong enough to withstand the weight of Callisto ( Callisto's mass is 1.076E23kg ) in standard Earth gravity though.
To get the ephemeris, I use the email version of JPL Horizons System. Basically, if you need an ephemeris form JPL Horizons you only have to send an empty email with subject header BATCH-LONG to their dedicated email address. The reply will tell you how to send a query to their system.
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The Orbiter of Orinetz Orbit Simulator
Saturday, January 9th 2010
Creating an Orbiter View for Orinetz Orbit Simulator was the second thing in my to-do-list for 2010 that I scheduled for January 10th 2010. Despite having a really hard to solve problem, I managed to complete the code on schedule. Thanks for my friends David Jackson, Larry454 and Michael Hay who have helped me solving that particular problem.
The Orbiter function in Orinetz Orbit Simulator is located in the right side of the web-page under View section. By activating the Follow Object checkbox, you can choose whichever object you want to follow during the course of the simulation.
The interesting part of this Orbiter View is by following any particular planet, you can observe the retrograde motion of other planets. The retrograde motion is caused by the fact that planets actually orbit the Sun along with our Earth. In the picture above for example, we can observe Mercury and Venus retrograde motion. More detail about the capability of Orbiter View can be found in this Help Article : How to use the Orbiter View ?.
Detailed path plotting featuring retrograde motion could be found in The Orbit of Planets as seen from other Planets, The movement of planet with eccentric orbit relative to other planet with eccentric orbit and mentioned briefly in Lunacentric Trajectory section of What will happen if moon have its own moon ?. Please note that these earlier simulations was made without using real ephemeris.
See Orinetz's Goals and Work Progress for year 2010
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Problem with Observer Orientation and Circular Orbit
Friday, January 8th 2010
When I try to write the JavaScript code for the orbiter of Orinetz Orbit Simulator, I found a geometric problem related to Observer Orientation vector and Circular orbit which solution I can't find despite thinking about it for several days, so I decided to put this question online to help people help me solve this problem.
Basically the problem is about finding the vector Pos(t+dt) if all other information mentioned in the picture above are known. The vectors Up, Front and Right are unit vectors, which means that their magnitude equal 1. All these unit vectors are orthogonal and all lines with the same colors have the same slope ( detail provided per advice from Larry454 ). These vectors are part of a rotational transformation matrix explained in Mathematics behind moving and rotating Observer and The Mathematics behind a simple 3D Engine.
The vector Fol is the position vector for the center of orbit, while the vector Pos(t) is the initial position of an observer. The angle α is the angle between the orbit and Front-Right plane. The angle dθ is the angle between Pos(t), Fol and Pos(t+dt).
Possible Forms of Solution
The possible solutions for this problem could come in two forms. The first form is a function which output Pos(t+dt) if all the the variables mentioned above are known. The second form of answer is a transformation matrix that could transform Pos(t) into Pos(t+dt) by means of matrix multiplication.
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Is Mathematics a part of Science?
Wednesday, December 23rd 2009
Whether mathematics is a part of science is a question that I started to wonder when I see the phrase "Science and Mathematics". Most people would answer yes, some people would answer no. The existence of the phrase "Science and Mathematics" itself however, is an evidence of either mathematics is not a part of science or there are disagreements about this. After thinking for 1 year, I come to the conclusion that the correct answer though is Not Always, as depicted in the image below.
While it is a fact that people who have interest in maths often have an interest in science, it is incorrect to say that maths could only be applied in science. Maths in itself is actually a language, a collection of symbol that we could use to convey any kind of information. It is not important whether the information was gathered from an empirical observation or from our own fantasy, as long as the rule that govern the interaction between mathematics objects are observed, that is mathematics.
Since mathematics is a language, stating that all mathematically correct equations are scientific is akin to stating that all grammatically correct sentences carry factual information. Of course this is incorrect. Mathematics as a language could be used to write rules of interaction between mathematical objects, regardless of whether those objects actually exists in reality or not. Just like any kind of languages, mathematics could also be used to tell lies. That is why we have a book titled "How to lies with Statistics", because statistics which is a part of mathematics could be used to tell non-factual things.
The other things I often observe people confuse are logic and science. Logic is a part of mathematics, but not always a part of science. The relationship between mathematics, logic and science could be depicted in the Venn diagram below.
This is apparent from the fact that logical inference rely heavily on the premises used. Thus the result of a logical inference could only be guaranteed to be true, if the premises are true and complete. Thinking logically will not guarantee that you arrive in the right conclusion if some of your premises are non-factual or your premise set is incomplete.
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If you want to make a revolution in science, never take a pseudoscientific path
Wednesday, December 23rd 2009
Theory of Relativity is a subject in physics that most people won't find as neither natural nor intuitive. Yet the value of this theory had been confirmed by various experiments done by many physicists around the world. However, I often observe people arguing about the scientific value of theory of relativity in various forum, online and offline. It seems that I was not the only one who had observe such occurrences, the author of XKCD website for example had drawn this particular webcomic to illustrate how often people come out with experimental thought that they think is going to "debunk" theory of relativity. Of course, they are going to find their thought experiment ignored by people who have learned more about the theory.
One particular cause for these occurrences is a meme that originated from the success of Galileo and Copernicus in debunking Aristotelian Geocentric Theory, which was believed by most authoritative figures of their time. For some people, this story might carry a message that whatever believed by most people and authoritative figures could be wrong. Add that particular message with attitude on the line of I am the smartest person in the world, it is inevitable that said person will try to contact the most authoritative figure in science, so they could get an audience for the theory they just developed but never test.
I could say this, because I myself used to believe in that particular meme. During my Senior High School years, a new physics teacher come to my class, saying something on the line that we have to believe what he taught us. Being young and hot-blooded, of course I object to that and I mentioned to him the story about Galileo challenging authoritative figure of his time to support my position. As I get older, I come understand that even if good idea could come from anyone there is a need for an authoritative figure. The fact that authoritative figures could be wrong, doesn't mean that they are always wrong or that authority is not necessary in science.
It is true that Galileo and Copernicus have indeed challenged what authoritative figures of their time believed. It is true that Theory of Relativity did challenged (to some degree) the widely believed Newtonian Mechanics at their time. However, both Galileo and Copernicus challenged the authority after they have done extensive researches and observation, while the authorities of that time never bother to do any observation works. Extensive Researches, Observations, Experiments and Peer Review are the main difference between what is scientific and what is pseudo-scientific.
It is still true that in science, anyone are welcome to challenge the authority. However, you should remember that it is not realistic to imagine that all those authority are there because of a massive scale conspiracy ( as most conspiracy theorist and crackpot often picture them ). Most of them are there because they had done various experiments and observations on their own. If you want to challenge them, you have to learn as much as what they had learned. Otherwise you will only annoy people with uneducated responses.
Seeing this issue from the other side, I often observe the same amount of arrogance come from people who have learned and understood the subject. Not something we should wondering about, since the number of people asking them the same question again and again aren't small. Most human being only have so much patience and once they run out of it, annoyance could be inevitable. However, it should be noted that blame-storming, name-calling and other form of arrogance are rarely productive activities. It would be delusional to say otherwise since this fact was also collected from the observation and experience of various psychologists, online group moderators and successful company managers.
Learning is an art that take a lifetime to master and forever to perfect. Thus patience, hard works and observation are always required in the process. In the other hand, teaching is also another art that take a lifetime to master and forever to perfect. Patience, hard works and observation are also necessary in this process. It is a fact that teachers who pay attention to their students teach better than they who don't. It is also a fact that students who pay attention to their teachers learn more than they who don't. No one should assume that they already know the ultimate truth and they should apply that assumption to everyone including themselves.
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