The Solar System

Sun
Sun is a star that too much is not different from other stars in the universe. Its form like the same ball like other stars with the radius around 1,392,000 kilometres and has the very high temperature. It have mass about 1,900,000,000,000,000,000,000,000,000,000 kg. Its distance is 149,597,980 km from the Earth or 1 AU (Astronomical Unit). Sun is in the class spectrum the star G that is the star is yellow that have the effective temperature about 6000 K. In its centre happens the process of the very horrifying nuclear explosion. That is the burning of four Hydrogen atoms become one core of the Helium atom. So as the temperature in its centre reached 15.000.000 K. In the exterior of the appearance Sun like disc is golden that is acknowledged as the Photosphere.
Is based on the data that is received it is estimated the Sun is 5 billion years old and will change to the giant's red star 5 billion following years.


Planet
Was based on the decision that was agreed to International Astronomical Union (IAU) last August 2006 was appointed that the planet is the celestial object that orbit around the Sun, have the mass that is enough so as the style of its gravitation can maintain its form as the almost round solid, as well as have the clean orbit in a sense do not cut or the overlap with the orbit of the other planet. In our Solar System that including the group of the planets are based on this definition are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.


Mercury
Mercury is the closest planet with the sun with the semi-major axis 0,387 AU or 57,909,175 km from the Sun. In its circulation surrounded the sun, Mercury needs time for 87,97 days with the period of the rotation 58,65 days. This planet has mass 3.3 x 1023 kg and diameter 4879.4 km. Imagined, because of its distance that very close with the sun, the temperature in the surface of this planet really extreme. During the day the temperature in the surface of this planet achieved 400 degree celcius (is hot enough to melt solid zinc) and -150 degree celcius tonight. The surface of Mercury is not as smooth as the planet earth. The surface of this planet is filled with the craters that are estimated because the collision of the meteor or asteroids resulting from the nonexistence of the atmosphere that covered this planet. Its surface materials consist of basaltic and anorthositic rocks and regolith.


Venus
Venus is the second planet closest with the sun after the planet mercury. Its semi-major axis is 0,723 AU or 108.208.930 km. Its diameter 12104 km with mass 4.87 x 1024 kg.This planet has the period of rotation 243,02 days (that a direction with the hour needle that is from the east to the west) that is significantly older than time that is needed to complete one round of its orbit over the sun (224,7 days).The content of the atmosphere in this planet most are carbondioxide (97%) and the rest of them nitrogen (its atmosphere is very thick). So as very impossible to believe in the existence of the life in this planet. Moreover, because of the amount of carbondioxide that is contained in its atmosphere cause the occurrence of the incident greenhouse effect. Although in covered with CO2, the experts astrobiology estimate the existence termobactery certain that still can be holding the life there.


Earth
The Earth is the only planet in the Solar System that inside is gotten by the life. Its mass around 5,980,000,000,000,000,000,000,000 kg with the diameter of the ball 12756 km. The density of the the Earth is the same as the density of Venus around 5,52 g/cm3. Time that is needed Earth to complete one round of its orbit over the Sun for 365,25 days. With the period of rotation about 23,93 hours. The compiler's component of the Earth atmosphere consist of 78% Nitrogen, 21% Oxygen and 1% Argon. Although having many similarities with Venus, but the temperature of the Earth surface not is as hot in the Venus surface. The temperature in the Earth surface in general 287 K. The Earth have a satellite that have a name the Moon.


Mars
The planet that often is acknowledged as red planet have the radius twice the radius of the Moon, that is as big as 3393 km and its mass 642,000,000,000,000,000,000,000 kg. With the density 3,8 g/cm3, smaller than the Earth’s density. The average distance of Mars from the Sun to 227,936,640 km with eccentricity of the orbit 0,093. Its rotation period and its orbital period are 1,026 days and 687 days (1,9 years) respectively. In broad outline, the surface part of the Mars, is divided into two, namely the southern part that is the area of the plateau that is full of the crater and indentations as well as the northern part that most consist of the plain that is full of the volcano that go out. The biggest crater that was found in this planet had diameter about 1800 km with the depth 6 km and was given a name Hellas. If in Earth is gotten the Everest mountain that is the highest mountain in Earth, evidently in the Mars planet also is gotten Volcano Mount that is highest in the Solar System that is given by the name “Olympus Mons” that have the height 24 km on the surface of the planet. The composition of the atmosphere of the Mars of the compiler's gas consisted of 95,3% CO2, 2,7% Nitrogen, 1.6%Argon, and other gas like Oxygen, carbon monoxide and steam. Mars have two satellites that are named Phobos and Deimos that are their respective have the period of the rotation and the period of the same revolution, so as the two satellites will always show the side that is same in its rotation surrounded the Mars.


Jupiter
Jupiter is the biggest planet in the Solar System. Its radius around 71500 km or around 11 Earth radius times with the mass around 1,900,000,000,000,000,000,000,000,000 kg. And its density 1,33 g/cm3, smaller than the Earth density. This is caused because of the compiler's material of this planet is dominated by light elements, those are Hydrogen and Helium. The average distance of this planet is 778,412,020 km (the eccentricity of the orbit 0,048) from the Sun and needs time 11,86 years to complete one round of its orbit over the Sun. The period of the rotation of this planet is very fast, only 9,8 hours. This matter is caused because of the compiler's composition Jupiter that most consisted of light elements and caused his form to become rather flat. With the radius comparison in the pole and in the equator was 1/15. In the surface of this planet is gotten a spot that apparently have the shape of oval and coloured reddish, that is named the Great Red Spot. This spot in fact is the area of the very big collection of the storm cloud. Its size as big as 420,000,000 km2.The compiler's composition of the Jupiter atmosphere consisted of 90% H2, 9% Helium, 0,07% CH4, 0,02% NH3, and other gas that the amount very few. This planet is also famous in a fourth manner his satellite that is given by the name of the Galileo satellite (Io, Europa, Ganymede, and Callisto), because that found the four of them was Galileo. Apart from the four satellites, Jupiter is still having 12 satellites more, that is Amalthea, Sinope, Pasiphae, Carme, Thebe, Leda, Himalia, Adrasthea, Elara, Lysithea, Metis, and Ananke.


Saturn
Saturn is the second biggest planet in the Solar System after Jupiter. Its diameter around 120660 km, its mass 569,000,000,000,000,000,000,000,000 kg and its density 0,705 g/cm3. Look at its density that is very small, make Saturn can be floating on the surface of water. The compiler's composition of this planet same like Jupiter that is dominated by light elements like Helium and Hydrogen. As a result the rotation of this planet become very fast (10,2 hours, fastest in the Solar System) and make this planet flat in its two poles. The compiler's composition of the Saturn atmosphere consist of 97% Hydrogen, 3% Helium, and Methane. The planet that be at a distance 1,426,725,400 km (with eccentricity of the orbit 0,056) from the Sun have the sidereal period 29,46 years. For quite a long time because of its distance that very far with the Sun. In Saturn also is gotten the great spot like available in Jupiter, that is the Great White Spot. This Great White Spot in fact is the storm cloud that its form is similar like the cloud cirrus available in the Earth atmosphere. In this spot is estimated the process of the crystallisation of ammonia happen. That is most interesting from this planet is rings that travel around it. That is located around 60330 km. These rings consist of thousands of rings that are made from particles that the size its bigger than particles that compiled Jupiter rings. These particles are measuring ice chunks 5 mm up to 5 m. It is wide that the ring reach 234000 km and its thickness only some hundred kilometres then. Like Jupiter, Saturn also has many satellites that accompany it. The satellite that is owned Saturn numbering 18 satellites, they are Pan, Rhea, Iapetus, Dione, Thetys, Mimas, Enceladus, Hyperion, Phoebe, Janus, Epimetheus, Atlas, Prometheus, Pandora, Telesto, Titan, Calypso, and Helena.


Uranus
The planet that have diameter 51118 km is in the distance 2,870,972,200 km (with eccentricity of orbit 0,77) so as to needs time 84 years to complete one round of its orbit. The period of its rotation only 17,9 hours (retrograde). This planet have the mass 86,800,000,000,000,000,000,000,000 kg and its density is 1,29 g/cm3. The compiler's components of the atmosphere of this planet including 83% Hydrogen, 15% Helium, and 2% Methane. Uranus also have the ring as in the case of Jupiter and Saturn. However, particles of the compiler of this rings are very thin and dark that consisted of stone chunks or material carbon. Uranus had 17 satellites that accompanied it they are Miranda, Ariel, Umbriel, Titania, Oberon, Cordelia, Ophelia, Bianca, Cressida, Desdemona, Juliet, Portia, Rosalind, Belinda, Puck, S/1997 U1, and S/1997 U2.


Neptune
Neptune have the mass around 102,000,000,000,000,000,000,000,000 kg or around 17 times more massive of the Earth. Its diameter is 49528 km with the density 1,64 g/cm3. Because of its distance that very far with the Sun that is around 4,498,252,900 km (eccentricity 0,009), this planet needs time around 164,8 years to complete one round of its orbit. The compiler's component of his atmosphere consisted of 74% Hydrogen, 25% Helium, and 1% Methane. Around this planet also is gotten the very thin ring. Neptune have 8 satellites those are Triton, Nereid, Naiad, Thalassa, Despina, Galatea, Larissa, and Proteus.

Ujian Persiapan Olimpiade Astronomi (Tes Observasi) (Waktu : 10 menit)

1. Tunjukkanlah rasi bintang Orion dan gambarkan pada kotak di bawah ini :









2. Lihatlah planet Mars dengan menggunakan teleskop. Apakah warna yang kamu lihat ?

3. Tunjukkanlah Summer Triangle dan sebutkan anggota-anggotanya !

4. Coba Kamu arahkan teleskop pada Azimut = 1350 dan Altitude = 450 .

Ujian Persiapan Olimpiade Astronomi (Tes Teori Essai) (Waktu : 90 menit)

1. Dua buah bintang di sebuah sistem galaksi di amati memiliki magnitudo mutlak yang sama. Kedua bintang memiliki magnitude sebesar 11,56 dan 12,11. Bila paralaks bintang yang lebih terang 0,”04, hitunglah jarak bintang yang lebih redup !

2. Sebuah bintang bertemperatur 4297 0C berada di luar sistem galaksi bimasakti.
Di daerah panjang gelombang berapakah bintang itu dapat terlihat dengan jelas ?

3. Jenifer hendak memotret sebuah bintang jauh yang besar sudutnya 57” dengan menggunakan teleskop reflector yang focus objektifnya 1400 cm. Tentukan berapa besar bintang tersebut setelah dipotret ?

4. Bintang “Scastron” dalam konstelasi “Jubelica” terdeteksi memiliki jarak 167 parsek. Jika diketahui magnitudo mutlak bolometricnya 0,58 dan koreksi bolometriknya 0,37. Apakah bintang ini dapat terlihat dengan mata telanjang ?

5. Berapakah energi yang dipancarkan sebuah bintang yang berjarak 4,2 tahun cahaya dari Bumi dengan Luminositas 4,21 x 1026 watt ?

The Tips Go to Astronomy Competition

Study from my friends who had followed astronomy olympiad, i want to give you a few tips to be success in the olympiad.

1.Before The Competition Day

* Check and recheck your healt in the nearest hospital or a doctor.
* Prepair your brain with eat the nutritious foods one month before competition,
* Not afraid to ask to your teachers or friends about the unknown lessons,
* Begin to be your self and optimist that you can be a winner.

2.In Competition or Olympiad

* Pray before test is begin,
* Answer with the bright reason, and then the jury can understand your work,
* Use other formula (your creativities) for finish your work to get plus scores from the jury,
* Center for the problems of test, no think the other except the problems.

Goodluck

What the Newest Lesson

On a clear sunny day, the sky above us looks bright blue. In the evening, the sunset puts on a brilliant show of reds, pinks and oranges. Why is the sky blue? What makes the sunset red? To answer these questions, we must learn about light, and the Earth's atmosphere.

The Atmosphere

The atmosphere is the mixture of gas molecules and other materials surrounding the earth. It is made mostly of the gases nitrogen (78%), and oxygen (21%). Argon gas and water (in the form of vapor, droplets and ice crystals) are the next most common things. There are also small amounts of other gases, plus many small solid particles, like dust, soot and ashes, pollen, and salt from the oceans.

The composition of the atmosphere varies, depending on your location, the weather, and many other things. There may be more water in the air after a rainstorm, or near the ocean. Volcanoes can put large amounts of dust particles high into the atmosphere. Pollution can add different gases or dust and soot.The atmosphere is densest (thickest) at the bottom, near the Earth. It gradually thins out as you go higher and higher up. There is no sharp break between the atmosphere and space.

Light Waves

Light is a kind of energy that radiates, or travels, in waves. Many different kinds of energy travel in waves. For example, sound is a wave of vibrating air. Light is a wave of vibrating electric and magnetic fields. It is one small part of a larger range of vibrating electromagnetic fields. This range is called the electromagnetic spectrum.


Electromagnetic waves travel through space at 299,792 km/sec (186,282 miles/sec). This is called the speed of light.

The energy of the radiation depends on its wavelength and frequency. Wavelength is the distance between the tops (crests) of the waves. Frequency is the number of waves that pass by each second. The longer the wavelength of the light, the lower the frequency, and the less energy it contains.

Color of Light

Visible light is the part of the electromagnetic spectrum that our eyes can see. Light from the sun or a light bulb may look white, but it is actually a combination of many colors. We can see the different colors of the spectrum by splitting the light with a prism. The spectrum is also visible when you see a rainbow in the sky.


The colors blend continuously into one another. At one end of the spectrum are the reds and oranges. These gradually shade into yellow, green, blue, indigo and violet. The colors have different wavelengths, frequencies, and energies. Violet has the shortest wavelength in the visible spectrum. That means it has the highest frequency and energy. Red has the longest wavelength, and lowest frequency and energy.

Light in The Air


Light travels through space in a straight line as long as nothing disturbs it. As light moves through the atmosphere, it continues to go straight until it bumps into a bit of dust or a gas molecule. Then what happens to the light depends on its wave length and the size of the thing it hits.

Dust particles and water droplets are much larger than the wavelength of visible light. When light hits these large particles, it gets reflected, or bounced off, in different directions. The different colors of light are all reflected by the particle in the same way. The reflected light appears white because it still contains all of the same colors.

Gas molecules are smaller than the wavelength of visible light. If light bumps into them, it acts differently. When light hits a gas molecule, some of it may get absorbed. After awhile, the molecule radiates (releases, or gives off) the light in a different direction. The color that is radiated is the same color that was absorbed. The different colors of light are affected differently. All of the colors can be absorbed. But the higher frequencies (blues) are absorbed more often than the lower frequencies (reds). This process is called Rayleigh scattering. (It is named after Lord John Rayleigh, an English physicist, who first described it in the 1870's.).

Contents

Why Is The Sky Blue?

The blue color of the sky is due to Rayleigh scattering. As light moves through the atmosphere, most of the longer wavelengths pass straight through. Little of the red, orange and yellow light is affected by the air.

However, much of the shorter wavelength light is absorbed by the gas molecules. The absorbed blue light is then radiated in different directions. It gets scattered all around the sky. Whichever direction you look, some of this scattered blue light reaches you. Since you see the blue light from everywhere overhead, the sky looks blue.


As you look closer to the horizon, the sky appears much paler in color. To reach you, the scattered blue light must pass through more air. Some of it gets scattered away again in other directions. Less blue light reaches your eyes. The color of the sky near the horizon appears paler or white.


The Black Sky and White Sun

On Earth, the sun appears yellow. If you were out in space, or on the moon, the sun would look white. In space, there is no atmosphere to scatter the sun's light. On Earth, some of the shorter wavelength light (the blues and violets) are removed from the direct rays of the sun by scattering. The remaining colors together appear yellow.
Also, out in space, the sky looks dark and black, instead of blue. This is because there is no atmosphere. There is no scattered light to reach your eyes.


Why Is The Sunset Red?

As the sun begins to set, the light must travel farther through the atmosphere before it gets to you. More of the light is reflected and scattered. As less reaches you directly, the sun appears less bright. The color of the sun itself appears to change, first to orange and then to red. This is because even more of the short wavelength blues and greens are now scattered. Only the longer wavelengths are left in the direct beam that reaches your eyes.

The sky around the setting sun may take on many colors. The most spectacular shows occur when the air contains many small particles of dust or water. These particles reflect light in all directions. Then, as some of the light heads towards you, different amounts of the shorter wavelength colors are scattered out. You see the longer wavelengths, and the sky appears red, pink or orange.

Continued

A clear cloudless day-time sky is blue because molecules in the air scatter blue light from the sun more than they scatter red light. When we look towards the sun at sunset, we see red and orange colors because the blue light has been scattered out and away from the line of sight.




The white light from the sun is a mixture of all colors of the rainbow. This was demonstrated by Isaac Newton, who used a prism to separate the different colors and so form a spectrum. The colors of light are distinguished by their different wavelengths. The visible part of the spectrum ranges from red light with a wavelength of about 720 nm, to violet with a wavelength of about 380 nm, with orange, yellow, green, blue and indigo between. The three different types of color receptors in the retina of the human eye respond most strongly to red, green and blue wavelengths, giving us our color vision.

Tyndall Effect

The first steps towards correctly explaining the colour of the sky were taken by John Tyndall in 1859. He discovered that when light passes through a clear fluid holding small particles in suspension, the shorter blue wavelengths are scattered more strongly than the red. This can be demonstrated by shining a beam of white light through a tank of water with a little milk or soap mixed in. From the side, the beam can be seen by the blue light it scatters; but the light seen directly from the end is reddened after it has passed through the tank. The scattered light can also be shown to be polarised using a filter of polarised light, just as the sky appears a deeper blue through polaroid sun glasses.

This is most correctly called the Tyndall effect, but it is more commonly known to physicists as Rayleigh scattering--after Lord Rayleigh, who studied it in more detail a few years later. He showed that the amount of light scattered is inversely proportional to the fourth power of wavelength for sufficiently small particles. It follows that blue light is scattered more than red light by a factor of (700/400)4 ~= 10.


Dust or Molecules?

Tyndall and Rayleigh thought that the blue colour of the sky must be due to small particles of dust and droplets of water vapor in the atmosphere. Even today, people sometimes incorrectly say that this is the case. Later scientists realized that if this were true, there would be more variation of sky color with humidity or haze conditions than was actually observed, so they supposed correctly that the molecules of oxygen and nitrogen in the air are sufficient to account for the scattering. The case was finally settled by Einstein in 1911, who calculated the detailed formula for the scattering of light from molecules; and this was found to be in agreement with experiment. He was even able to use the calculation as a further verification of Avogadro's number when compared with observation. The molecules are able to scatter light because the electromagnetic field of the light waves induces electric dipole moments in the molecules.

Why not Violet?

If shorter wavelengths are scattered most strongly, then there is a puzzle as to why the sky does not appear violet, the color with the shortest visible wavelength. The spectrum of light emission from the sun is not constant at all wavelengths, and additionally is absorbed by the high atmosphere, so there is less violet in the light. Our eyes are also less sensitive to violet. That's part of the answer; yet a rainbow shows that there remains a significant amount of visible light colored indigo and violet beyond the blue. The rest of the answer to this puzzle lies in the way our vision works. We have three types of color receptors, or cones, in our retina. They are called red, blue and green because they respond most strongly to light at those wavelengths. As they are stimulated in different proportions, our visual system constructs the colors we see.
Response curves for the three types of cone in the human eye

When we look up at the sky, the red cones respond to the small amount of scattered red light, but also less strongly to orange and yellow wavelengths. The green cones respond to yellow and the more strongly-scattered green and green-blue wavelengths. The blue cones are stimulated by colors near blue wavelengths which are very strongly scattered. If there were no indigo and violet in the spectrum, the sky would appear blue with a slight green tinge. However, the most strongly scattered indigo and violet wavelengths stimulate the red cones slightly as well as the blue, which is why these colors appear blue with an added red tinge. The net effect is that the red and green cones are stimulated about equally by the light from the sky, while the blue is stimulated more strongly. This combination accounts for the pale sky blue color. It may not be a coincidence that our vision is adjusted to see the sky as a pure hue. We have evolved to fit in with our environment; and the ability to separate natural colors most clearly is probably a survival advantage.





A multi-coloured sunset over the Firth of Forth in Scotland.


Sunset

When the air is clear the sunset will appear yellow, because the light from the sun has passed a long distance through air and some of the blue light has been scattered away. If the air is polluted with small particles, natural or otherwise, the sunset will be more red. Sunsets over the sea may also be orange, due to salt particles in the air, which are effective Tyndall scatterers. The sky around the sun is seen reddened, as well as the light coming directly from the sun. This is because all light is scattered relatively well through small angles--but blue light is then more likely to be scattered twice or more over the greater distances, leaving the yellow, red and orange colors.

A blue haze over the mountains of Les Vosges in France.


Blue Haze and Blue Moon

Clouds and dust haze appear white because they consist of particles larger than the wavelengths of light, which scatter all wavelengths equally (Mie scattering). But sometimes there might be other particles in the air that are much smaller. Some mountainous regions are famous for their blue haze. Aerosols of trepans from the vegetation react with ozone in the atmosphere to form small particles about 200 nm across, and these particles scatter the blue light. A forest fire or volcanic eruption may occasionally fill the atmosphere with fine particles of 500-800 nm across, being the right size to scatter red light. This gives the opposite to the usual Tyndall effect, and may cause the moon to have a blue tinge since the red light has been scattered out. This is a very rare phenomenon--occurring literally once in a blue moon.

About My Blog

My Blog is astronomy weblog uses english that contained many astronomy articles, matters of astronomy et cetera. AIF also served free download of astronomy exercises. It is hoped all that the author gave could be useful for all of them.