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Boys, set your calculator to polar mode, and draw a graph of
r=4sin(3θ), then set the first interval of [0,π] and the second one: [0, 2π]


[0,π]

[0,2π]

They looks exactly the same, isn’t it?

And if we take of the integral of these two to find the area, for the graph with interval [0,π], area = 4π, but for the graph with [0,2π] the area is 8π, thus, which one is the “true” one we want to find?

I. The Form of Trig Polar Equation

For a trig polar equation, the form is looks like: r=asin(bθ) or cos etc…

a decide the “size of the graph”

b decide the number of “blades”

II. Odd number b and Even number b

The thing is vital :

*The number of blades = 2b

-For even number of b, the blades created are separated(here b=4, so there are 8 “blades”):

-For odd number b, the “blades” are covered with each other, take example of r=4sin(3θ) with [0, 2π], it actually graphed 6 blades, but each two are in the same position covered the another one, so we could only see three. If we do the integral to calculate its area, we get the area of 6 blades.

Thus, if we want to find the area of 3 blades, you can set the interval of [0, π], or just simply divide the area with interval [0, 2π] by two

It’s a very interesting trick dealing with polar equation.

P.S. : hpbsd for me~

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Landing has been a big problem to Falcon. To achieve the goal of recycling space rocket, SpaceX engineers calculate orbit by many factors, many times the problem is at the moment of landing, people could see the rocket is already on the landing pad on the ocean, but the rocket just not stable and fall down then blow up.

So, if that is possible to set a pad with electromagnet to stick the rocket while landing?

Idea of EM Pad

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ʻOumuamua is Not a Spacecraft but a Comet

Deemo Chen, grade 11 student. Barstow School – Ningbo Campus.

Abstract

1I/2017 U1 (‘Oumuamua), a recently discovered asteroid in a hyperbolic orbit, is likely the first macroscopic object of extrasolar origin identified in the solar system. This paper mainly gives reasons why ‘Oumuamua should be a comet, by explaining three unusual behaviors of ‘Oumuamua which are unnormal ratio, strange track eccentricity, and Peculiar Acceleration; disproving four main hypothesizes to say ʻOumuamua is not a comet, then provide an evidence of reflectivity of surface of ʻOumuamua to prove ʻOumuamua in a regular interval of comet group. Thus, ʻOumuamua is most likely to be a comet.

Keywords: ʻOumuamua (1I/2017 U1); extraterrestrial intelligenceISM: individual objects (1I&2017 U1)minor planets, asteroids: generalminor planets, asteroids: individual (1I&2017 U1).

Introduction:

ʻOumuamua (1I/2017 U1) is an object from outside of the solar system by first observed by Panoramic Survey Telescope and Rapid Response System(Pan-STARRS) located at Haleakala Observatory, Hawaii, USA (“IAU MPC”), from the IAU website, we can find that ʻOumuamua is also the first object human ever observed from outside the solar system. We are trying to figure out where exactly it came from. The thing is, there are several things shows it is not an ordinary object and can possibility to be a spacecraft may be made by aliens. However, I do not agree with this statement; I tend to describe it is an unusual comet by against three main theories exist which say ʻOumuamua is not a comet.

The ratio and shape of ʻOumuamua

Since we cannot use an optical telescope to truly see how ʻOumuamua looks like, the only way we can use it make the scientific hypothesis of the shape of it.   For a rigid body, it will rotate around the maximum inertia axis(MIA), which is the axis with the most considerable moment of inertia. Dynamically, it can be proved that the rotation of the rigid body around other inertia spindles is unstable if we consider the slight deformation damping of the object.

Figure 1Explorer_1 From NASA Accessed 2019/1/13 https://heasarc.gsfc.nasa.gov/Images/explorer/explorer1.gif

Just like the graph of Explorer_1, which is the first artificial satellite launched by America, it has a long and thin shape. The blue line points the long spindle of Explorer_1, and that is the minimum inertia spindle of this structure, the red line shows the maximum inertia spindle. People at that time hope the satellite could rotate around the long axis, but the result of that be the Explorer_1 cannot stabilize its posture at all, even they did successfully launch the satellite, but Explorer_1 cannot do many planned tasks.

In this way, we can assume that ʻOumuamua is rotating around its MIS. And the diagram below helps us to figure what could be the possible shape of ʻOumuamua.

Light curve of ʻOumuamua. All of the magnitudes have been scaled using the measured colors; the error bars indicate 1σ photometric errors. (Meet, et al. 2)

According to the Light curve of ʻOumuamua, the red dotted line corresponds 10:1:1 triaxial ellipsoid with a 20% variation in albedo across the surface (Meech et al. 2), and the dotted curve made by observation data from different telescopes of ʻOumuamua shows a nearly perfect fitness to the light curve model of a 10:1:1 triaxial ellipsoid. By analyzing the interval between two relative curve minima points, we could approximate the rotating period as 7.34 h. Also, by the hydrostatic balance theory, the size of ʻOumuamua cannot construct itself to be a sphere.

For a rigid body, it is tough to rotate in this way, it will quickly be rapture, and it from outer space and we even cannot figure out it from which galaxy (Ye, et al. 3), so it must have traveled in space for a long time, and that means ʻOumuamua should keep rotating like this for a long time, the possibility of that should be very small, because if P(x)= . P(d) should be minimal (d refers to the distance ʻOumuamua travel, x= ʻOumuamua keep this long and thin shape), and because this shape is too unusual for human, so many people believe ʻOumuamua is an artificial object or spacecraft.

However, the evidence of this hypothesis has some vulnerabilities.

First, the model of the shape of ʻOumuamua have some problem, since we do not have the graphic evidence of the shape, if only according to the light curve, there are much more shapes could fit this model, or there is a light absorbing material covered on, and the following statement about “rigid body” cannot works because other shapes could prevent them from rapture.

Second, we do need to assume that ʻOumuamua is a rigid body, because for a rigid body, they will rupture because of their inside force, so if ʻOumuamua is not a rigid body but made by relatively elasticity materials, in this way, ʻOumuamua could keep a long and thin shape but not broke.

Third, I think even ʻOumuamua truly looks long and thin, that is not a strange thing to human, because if one thing could exist in this world by way we know about physics, then it is properly, “Practice is the sole criterion for testing knowledge”, we should believe in data, whatever how impossible it looks like.

In this way, I think the shape of ʻOumuamua has nothing to doubt about.

The Orbit of ʻOumuamua

Figure 2 Meech, et al. 3

The path of Oumuamua (1I/2017 U1) through the Solar System.

“The orbit of a typical Halley-type comet is shown for comparisonas the solid grey line. The inset shows the inner Solar System; the solid linesegment along the trajectory taken by ‘Oumuamua (dashed)indicates the short window of two weeks during which it was bright” (Meech, et al. 1), As we can see that its track eccentricity is only 1.1956 ± 0.0006, it looks got into the solar system vertically to the zodiac and soon go back the same way, it just like aim to the sun. So, it could easily be seems as a spacecraft want to use the gravity of the sun to redirect its orbit because it is the best way we can think to save the energy for a shuttle.

Orbit offset

Marco Micheli’s team analyzed the full observational dataset, which includes 177 ground-based and 30 HST based astrometric positions (for a total of 414 scalar measurements), applying the procedures and assumptions discussed in Methods. Their analysis shows that the observed orbital arc cannot be fitted in its entirety by a trajectory governed solely by gravitational forces due to the Sun, the eight planets, the Moon, Pluto, the 16 most massive bodies in the asteroid main belt and relativistic effects14. As shown in diagram D1-a, the residuals in right ascension and declination of the best-fitting gravity-only trajectory are incompatible with the formal uncertainties: ten data points deviate by more than 5σ in at least one coordinate, and 25 are discrepant by more than 3σ. Furthermore, the offsets (as large as 22″ for the 2017 October 14 Catalina observation) are not distributed randomly but show clear trends along the trajectory. (Micheli 1)

Diagram 1(D2):

The most reasonable reason for the offset of the orbit is the force of comet dust which will give a power to the object when it spread out of the object, however, by the data from Micheli’s team (Micheli 3), they built a model of comet could have this kind of behavior, they found even 2kg of the dust from the object is enough for telescope  to observe, the thing is, from the actual diagram, we cannot see any dust from ʻOumuamua.

Figure 3Micheli 3

Is that means ʻOumuamua is not a comet but could change its orbit by itself and become a spacecraft? It could be a reasonable guess, but I think there is a better explanation that the object has released only a small quantity of dust, probably in the form of larger grains which are hard to see. 

Also, by the theory of Fitzsimmons’s team, we have another way to explain that there is a cover on ʻOumuamua’s surface which prevents the ice inside of ʻOumuamua spread out from itself, and the cover is so thick that even the sun cannot put effects on ʻOumuamua in that short time, that they reported the spectroscopic characterization of ‘Oumuamua,  and finding it to be variable with time but similar to organically rich surfaces found in the outer Solar System. The observable ISO population is expected to be dominated by comet-like bodies in agreement with our spectra, yet the reported inactivity implies a lack of surface ice. (Fitzsimmons, Alan, et al 4). This is consistent with predictions of an insulating mantle produced by long-term cosmic ray exposure. An internal icy composition cannot, therefore, be ruled out by the lack of activity, even though ‘Oumuamua passed within 0.25 AU of the Sun.

So ʻOumuamua is more likely to be a comet in this way.

The theory to be a LightSailBecause of the usual orbit of ‘Oumuamua, it could consider an artificial origin; one possibility is that Oumuamua is a LightSail, floating in interstellar space as debris

from advanced technological equipment (Bialy 1), As a solar sail, its propulsion is dependent on solar radiation alone. Solar photons exert radiation pressure on the sail, producing a small degree of acceleration. Thus, the solar sail will be propelled by force from sunlight itself, and not by the charged particles of the solar wind.

       Even Mr. Bialy mentioned that ‘Oumuamua could be alien craft since its orbit is so unusual: “Alternatively, a more exotic scenario is that ‘Oumuamua may be a fully operational probe sent intentionally to Earth vicinity by an alien civilization.” (Bialy 4)

       It is just an educated guess of the orbit of ‘Oumuamua, but I think this hypothesis did not consider more, because we already prove that ‘Oumuamua is rotating, but if LightSail works, it must let one side of itself toward the sun, so the theory of a LightSail could not work.

The reflectivity of the surface

       Since all hypothesis of saying is not a comet be proved as wrong, here I can give relevant evidence that ‘Oumuamua is a comet.

Figure 4Meech 3

The reflectivity of the surface of ‘Oumuamua. The surface reflectivity of ‘Oumuamua is consistent with D-type asteroids and comets. Data are normalized to 1 at 0.65 μ m, and the error bars reflect the 1σ standard deviation. (Meech 3)

       From the data given by Meech’s team,‘Oumuamua’s reflectivity is pretty close to D-type asteroids and comets, compare to Comet 67P, Comet 9P, and Comet 103P, it does not have much differentness.

One possible way to check what‘Oumuamua truly is

The challenge of reaching the object within a reasonable timeframe is formidable due to its high heliocentric hyperbolic excess velocity of about 26 km/s (Hein 1); Much faster than any vehicle yet launched, Launching a spacecraft to ’Oumuamua in a reasonable timeframe of 5-10 years requires a hyperbolic solar system excess velocity between 33 to 76 km/s for mission durations between 30 to 5 years. (Hein 4) It is demonstrated that based on existing technologies now human have such as from the Parker Solar Probe, launchers such as the Falcon Heavy and Space Launch System could send spacecraft with masses ranging from dozens to hundreds of kilograms to 1I/’Oumuamua, if launched in 2021. A further increase in spacecraft mass can be achieved with an additional Saturn flyby post solar Oberth maneuver. The potential of more advanced technologies such as laser electric propulsion, solar and laser sails would also allow for chasing ’Oumuamua, although their development will likely push launch dates farther into the future and might be more attractive for reaching future ‘Oumuamua-like objects. And we can chase it in 2029.

Conclusion

Even the shape of ’Oumuamua is strange. Its orbit changes but we cannot observe any dust, and the model is suitable to be a LightSail, but all we can find a reasonable explanation. So `Oumuamua is a comet –a tiny one, with perhaps different chemistry and an unusual shape, but colored like Solar System comets, and outgassing like our comets or covered with an organic layer. So, we were indeed lucky to find it, but we did not need to be too fortunate to find an interstellar asteroid.  And we still have the chance to take a clear picture of this comet to see how exactly it looks like if we want to.

Works Cited

Bialy, Shmuel, and Abraham Loeb. “Could Solar Radiation Pressure Explain ‘ʻOumuamua’s Peculiar Acceleration?” The Astrophysical Journal Letters 868.1 (2018): L1.

<http://iopscience.iop.org/article/10.3847/2041-8213/aaeda8/meta>. Accessed on 19 December 2018.

Fitzsimmons, Alan, et al. “Spectroscopy and thermal modelling of the first interstellar object 1I/2017 U1 ‘ʻOumuamua.” Nature Astronomy 2.2 (2018): 133.

<https://www.nature.com/articles/s41550-017-0361-4>. Accessed on 19 December 2018.

Hein, Andreas M., et al. “Project Lyra: Sending a Spacecraft to 1I/’ʻOumuamua (former A/2017 U1), the Interstellar Asteroid.” arXiv preprint arXiv:1711.03155 (2017).

<https://arxiv.org/abs/1711.03155>. Accessed on 19 December 2018.

Meech, Karen J., et al. “A brief visit from a red and extremely elongated interstellar asteroid.” Nature 552.7685 (2017): 378.

<https://www.nature.com/articles/nature25020>. Accessed on 19 December 2018.

Micheli, Marco, et al. “Non-gravitational acceleration in the trajectory of 1I/2017 U1 (‘ʻOumuamua).” Nature 559.7713 (2018): 223.

< https://www.nature.com/articles/s41586-018-0254-4>. Accessed on 19 December 2018.

“The International Astronomical Union Minor Planet Center.” IAU Minor Planet Center, minorplanetcenter.net//iau/lists/MPDiscsNum.html.

https://minorplanetcenter.net//iau/lists/MPDiscsNum.html. Accessed on 8 January 2018

Ye, Quan-Zhi, et al. “1I/2017 U1 (‘ʻOumuamua) is hot: imaging, spectroscopy, and search of meteor activity.” The Astrophysical Journal Letters 851.1 (2017): L5.

<http://iopscience.iop.org/article/10.3847/2041-8213/aa9a34/meta>. Accessed on 19 December 2018.

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教你通行暗网,但暗网不是个好地方

暗网,隐网,深网,听着很吓人,是吧。在媒体的推波助澜下,这些东西的确变得神秘而又不可触碰起来。但是,说实话,有什么难的呢,难道每个暗网用户都是计算机高手不成?

什么是暗网?

这里有点区别,倒不如这么说吧,无法直接由搜索引擎搜索到的页面都属于隐网,也就是The Hidden Web。 媒体搞了一个冰山理论,什么绝大多数的网络都是罪犯的天堂,也是可笑之极, 那我知乎的个人编辑页面也成为犯罪天堂咯?这里所要澄清的是,隐网的确很多,但是我们即将要讨论的暗网却并非如此。

暗网, 数量在几万左右,不时关闭,不时开启,有违法色情,毒品与枪支的交易,当然还有FBI的钓鱼网站。这也是大家所熟知的。如果要深入了解下具体,可以看看这篇文章:出于好奇,我去暗网里瞧了瞧 —— 你就别去了

暗网网站的网址一般都如此:https://3g2upl4pq6kufc4m.onion/,而这是无法用普通的浏览器访问的,而是一个加密浏览器,也就是我们的Tor。

如何使用Tor

加密,加密,加密!这很重要!如果不想某一天被人提着榔头找到家就请选择一个可靠的VPN,并一直把它挂起来。寻求VPN的看这篇文章 

然后我们直接访问Tor官网下载安装你的Tor浏览器

打开后我们选择配置,因为中国封锁了Tor,所以我们需要一个网桥。

选择“我所在的国家对Tor进行了封锁”

我们的第一选择是选择内置网桥,这里选择“meek-azure” 然后点确定

然后就开始了等待,Tor的一切都很慢,因为它本质上是个高度加密的浏览器

如果成功,就会看到如下界面:

如果失败了,就需要自己获取网桥,点击Tor的官方项目获取3个网桥,在Tor网络设置中点“输入获取的网桥”粘贴即可。

到此,我们已经连入Tor加密网络,可以访问暗网网址。

PS: DuckDuckGo是暗网的搜索引擎, 我们的确可以访问平时的网络,但那也太慢了, 并且毫无意义

工具

Hidden Wiki, 用来找暗网网址

必须在Tor浏览器中才能使用的活跃暗网网站搜寻器

  1. The Hidden Wiki

http://zqktlwi4i34kbat3.onion/wiki/index.php/Main_Page

2. Deep Web Links – Dark Web Links

http://wiki5kauuihowqi5.onion/

3. TORCH

http://xmh57jrzrnw6insl.onion/

Torch很有名

4. Not Evil

http://hss3uro2hsxfogfq.onion/

5. Daniel’s Onion Link List Raspberry Pi Directory

一个Tor 网站目录 ,据说在一个树莓派上运行

总结

引用斯锐恩插的一句话:

正常人都会准备攒紧口袋,去逛逛成人网站,找找不常见的资源,做一个合理的投资。不管怎么样,新世界的大门已经敞开了,至于是天堂还是地狱,这是一个见仁见智的问题 —— 因为 Deep Web 并不完全是一个黑暗且残酷的网络深渊,除去少量毒品交易、军火走私、邪恶的宗教犯罪集团在此猖獗之外,大部分沉寂在这片深海里面的都是一些罕见的档案、文件以及高质量的学科知识。

当然不得不承认,在撰写你的毕业论文时,脑子里总会漂浮着这样一个事实:我和军火走私贩、毒贩子在共用一个检索系统。

http://www.vice.cn/read/a-brief-guide-to-deep-web

总之,

别吐, 别作恶, 欢迎来到 新世界

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Let We do Moon Stacking! And Processing

Since I moving my telescope to my school for my Astronomy Club, I put it for a long time because my club is still weak and no one in the club could be seem as a real club number. But I set up a small observation recently with another guy who are not in my club, and I took 16 photos of moon by my lovely A7RIII, however, the truth prove that it is useless to stack 16 photos, but I think it is a nice try.

All things: 16 original photos, AutoStakkert 3, RegiStax and Photoshop

I. Stacking

Open AutoStakkert 3, put 16 photos into it.

For moon, choose “Surface”, because my materials have low noises, so I set “2” as my Noise Robust.

Use [Ctrl]+[Left Click] to choose a area with obvious characteristics

Click “2)Analyse”

Hint: Close all other software, it need RAM

After Analyse. we need to choose Aps for locate different frames. Click “Manual Draw”, then click “Place AP grid”

For “Stack Options”, choose tif format and do not use its sharpening function, RegiStax and Photoshop are much better than it.

Finally, we get a big pic, but it looks has no difference comparing to the original materials, so we need to do sharpen work.

II. Sharpening

Put the stacked material into RegiStax, than move the Slider, the purpose here is to make the graph as clear as it can be, but without noise

And for the works be done on Photoshop, since it is easy to do, just ignore it.

Final Work

Mooooooooooon

I know it looks bad, here are my tips:

  1. Take video instead of photos
  2. Make the materials focus on the objects but not space, because the space will include a lot of pixels which will let the software unwork.
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How I understand the Ideal Gas Law

After learning the Gas law, that I got some general idea of the beauty of equations, I think the expression of textbooks is pretty strange, they trying to divide one simple formula to several different unclear ones, hmm…

I think the better the equation is the more factors it includes in; it does not let the question become complicated but even make it even simpler because people do not need to think about do they include some factors or not, so which even help them understand the concept better.

Here is the Ideal Gas Equation:

PV=nRT

Then we have:

-The Boyle’s Law:

P1V2=P1V2

-The Charles Law:

V1/T1=V2/T2

-The Gay-Lussac’s Law:

P1/T1=P2/T2

All three equations above could be explained by the Ideal Gas Equation because they just keep the other two factors in constant, and do a “simplified equation” of two other factors remained.

That we can notice that only the Boyle’s Law is two factors multiply with each other, because they are on the same side of the Ideal Gas Equation, so if we keep the other two factors in constant, they must have an inverse relationship.

Which is P1V1=nRT, P2V2=nRT, because nRT is the same, so we got the Boyle’s Law. However, there could be less deviation between the Ideal Gas condition and the real gas condition, because we can put more factor here. Assume we consider the size of the particle effect the behavior, maybe we can invent a new equation.

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Standard of Being My “Friend”

There is a man who has similar intelligence and wisdom as I do, I do not need to explain something over and over again, and again, he can understand me, he does understand me, which I can feel it.

We have the same hobbies, senses, we get together every day when I got some misunderstanding of academic stuff, he knows what is the way to point it out for me, he could be annoying, but also quiet.

We could argue for an academic topic for a long time and goes crazy, but have fun together.

And I found, that person is

Me, I & Myself

We,

Are Forever.

I am tired.

Tired of “Understanding”

 

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