Name: João Fernando Alves da Silva Class: 7-4 Number: 10

Name: João Fernando Alves da Silva Class: 7-4 Number: 10

What is the constitution of the Solar System? The Solar System is constituted not only by planets, which have satellites, but also by thousands of asteroids and millions of comets. The Solar System, is the system dominated by a central star, the Sun, and by the bodies that move in orbit, around it. In this set are included 8 main planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, their 61 natural satellites, thousands of asteroids, comets, meteorites and interplanetary dust. Lets see the story of the Sun and the 8 planets

The Sun is our nearest star. All the planets in the Solar System orbit around it and have different periods. The Sun has a mass 332 959 times superior to the Earth s mass. It is mainly constituted by hydrogen and helium, the lightest gases we have. It occupies a peripheral position in our Galaxy, which means it is 33.000 light years way of the Galactic Center. We are in one of the spiral arms of the Orion s arm. The Sun s year is approximately 230 million terrestrial years and its orbital velocity is 250 km/s. The other bodies in the Solar System join the Sun in this journey. The Sun is 4,5 billion years old and possesses a rotational movement around its own axis like the other planets in the Solar System. The Sun is not a solid body, because the spots placed near the middle of the solar disc move faster than the ones that are more apart. Considering that, the place near the Equator makes um turn every 27 days. This period increases with the latitude so the region near the poles has a period of 32 days. The differentiated movement of the Sun s rotation provokes the distortion of its magnetic field. Sometimes it becomes so chaotic that a period of intense solar activity called maximum is generated. The Sun occupies a modest place in one of the arms, 300 000 light year away of the center and its translation period around the Galaxy is 200 million years with a velocity of 250 km.s -1. Like our Galaxy it is estimated that over 10 000 million galaxies exist in the Universe. The Sun is essentially constituted by hydrogen and helium but also by small amounts of oxygen, nitrogen, carbon, lithium, beryllium and boron. The temperature of the Sun s core rounds 20 million degrees and the pressure is equivalent to 11 billion atmospheres.

Mercury is the 1st planet of the Solar System. It is the smaller and most intern, taking 87,969 terrestrial days to complete its orbit around the Sun. Mercury s orbit has the bigger eccentricity and smaller axial inclination of the Solar System, completing 3 rotations around its axis every 2 orbits. icy Mercury s appearance is similar to the Moon, with impact craters and smooth plains, no natural satellites and a non substantial atmosphere. Unlike the Moon, it has a big amount of iron in the core that generates a magnetic field almost 1% stronger than the Earth s magnetic field. It s a exceptionally dense planet thanks to the relative size of its core. Its surface temperature varies from 100 to 700 K (-173 C to 427 C). Mercury doesn t have natural satellites or a substantial atmosphere. Average distance to the Sun (km) 57.910.000 Orbital period - 87,9691 days Average orbital velocity- 47,87 km/s Natural Satellites- none Equatorial diameter- 4 879,4 km - 0,383 Earths Surface Area- 7,48 10 7 km² - 0,147 Earths Volume - 6,083 10 10 km³ - 0,056 Earths Mass -3,3022 10 23 kg -0,055 Earths Temperature variation / -173 a 427 ºC Atmosphere s composition : helium, sodium and oxygen.

Venus is the second planet of the solar system with a translation period of 224,65 days. Venus completes a turn around its axis every 243 terrestrial days, which is by far the slowest rotaion of the Solar System s planets. A day in this planet is bigger than a year. Venus has a dense atmosphere, composed mainly by carbon dioxide, but also by nitrogen. The amount of nitrogen in Venus' atmosphere is almost the same as the amount of oxygen on Earth..The enormous amount of carbon dioxide creates a strong greenhouse effect that elevates the surface temperature to 480 C in the less elevated areas around the Equator. That makes Venus hotter than Mercury, even though Venus is twice more distant from the Sun than Mercury ansd receving only 25% of its solar radiation (2.613,9 W/m² in the superior atmosphere and e 1.071,1 W/m² on the surface). Venus doesn t have natural satellites. Average distance to the sun (km) 108.200.000 Orbital period - 224,7 days Average orbital velocity- 35,02 km/s Natural satellites- none Equatorial diameter- 6.051,8 Km Surface area- 4,60 10 8 km² Density - 5,204 g/cm³ Mass - 4,8685 10 24 kg Surface temperature- 461,85 ºC Atmosphere s composition: helium, sodium, oxygen, carbon dioxide, sulfur e water vapor.

The Earth is the 3rd planet of the Solar System and the 5th in diameter. The Earth has unique condition: a big amount of water, tectonic plates and a strong magnetic field. The atmosphere interacts with the other systems. Modern Science considers that the Earth is the only planet with life as we know it. It interacts with other objects of the space, including the Sun and the Moon. Nowadays, the Earth orbits the Sun once every 366,26 rotations the equivalent to.365,26 solar days. The Earth s rotation movement takes about 24 hours. On the inside temperatures around 5.270 K are reached. The planet s internal heat was generated during its formation and additional heat is constantly generated by the decay of radioactive elements such as uranium, thorium and potassium. The heat flux from the interior to the surface is small when compared to the energy received from the Sun. The Moon is its only natural satellite and orbits the planet for 4,53 billion years. The Moon is responsible for the tides and stabilizes the inclination of the terrestrial axis. Besides it gradually diminishes the planet s rotation. Average distance to the Sun (km) 149.600.000. Orbital period - 365 days, 6 hours e 9 minutes Average orbital velocity- 29,7847 km/s Natural Satellites- Moon Equatorial diameter- 12 756,27 km Surface area- 5,10072 10 8 km² Average density- 5,515 g/cm³ Mass - 5,9742 10 24 kg Temperature variation- -84,15 to 59,85 ºC Composition by mass: 34,6% iron; 30,2% de Oxygen; 15,2% de Silicon; 12,7% de Magnesium ; 2,4% de Nickel; 1,9% de Sulfur; 0,05% de Titanium

Mars is the 4th planet of the Solar System and the last of the four telluric planets. It is located between our planet and the asteroids waist, about 1,5 AU from the Sun (that is, a time and a half the distance form the Earth to the Sun). Mars is considerably similar to the Earth: its day has almost the same duration has a terrestrial day and it has the same number of seasons. Mars is known since Antiquity and stands out due to its reddish aspect, reason why it is often called the Red Planet. In comparison to Earth, Mars has 53% of its diameter, 28% of its surface and 11% of its mass. Its translation period is 687 days, its rotation period is almost the same as the Earth s period, taking 24h 40 min. The temperature in Mars can be vary low. In the warmer days, Mars is still a very cold place, reaching +17ºC.In the coldest days the temperature might reach -142ºC. Mars has two moons, Phobos and Deimos, which have irregular shape Average distance to the Sun(km) 227.940.000. Orbital period - 686,971 days Average orbital velocity- 24,077 km/s Natural satellites- Phobos and Deimos Equatorial diameter - 6 792,4,4 km Surface area- 1,45 10 8 km² Average density- 3,934 g/cm³ Mass - 6,4185 10 23 kg Temperature variation- -87 a -5 ºC Composition by mass: 95,72% of carbon dioxide; 2,7% nitrogen; 1,6% de argon; 0,2% oxygen; 0,07% carbon monoxide; 0,03% water vapor; 0,01% nitric oxide

Jupiter is the biggest planet of the Solar System, not only in diameter but also in mass. It is also the 5th planet. Jupiter is one of the four giant gaseous planets which means it is not primarily composed by solid matter. It is mainly composed by hydrogen and helium. Its average temperature is 121 ºC and its rotation takes 9 hours and 56 minutes and translation 11 years and 315 days. Jupiter has 64 moons and 4 rings formed by dust and pieces of rock. Average distance to the Sun (km) 778.330.000. Orbital period - 4331,572 days Average orbital velocity 13,07 km/s Natural satellites- 63 Equatorial diameter- 142 984 km Surface area - 6,218 10 10 km² Volume- 1,431 10 14 km³ Mass - 1,899 10 27 kg Average temperature - -108 ºC Composition by mass: 2,0% hydrogen; 2,0% helium; 0,3% methane; 0,026% ammonia; 0,0006% phosphorus; 0,0004% water vapor.

Saturn is the 6th planet of the Solar System and it is located between Jupiter and Uranus. It is the second biggest after Jupiter, being one of the gaseous planets of the Solar System, although it is the one which has the smaller density. So few dens, that if the was a ocean big enough, Saturn would float on it. Its rotation takes approximately 10,5 hours and it s translation 29 terrestrial years. Saturn is a gaseous planet, mainly constituted by hydrogen (97%) and a small portion of helium and other elements. It has a elevated number of satellites, 62, and it is surround by a complex of rings, composed by dozens of individual rings separated by intervals. Its temperature rounds -178 ºC. Average distance to the Sun(km) 1.429.400.000. Orbital period - 10 759,22 days Average orbital velocity- 9,69 km/s Natural satellites- 62 Equatorial diameter- 120 536 km Surface area- 4,27 10 10 km² Volume- 8,2713 10 14 km³ Massa - 5,6846 10 27 kg Average temperature -139 ºC Composition by mass: The atmosphere of Saturn is constituted by 96% of hydrogen and 3% of helium (by volume).

Uranus is the 7th planet of the Solar System, located between Saturn and Neptune. It has 27 satellites and a thin ring of dust. Its equatorial diameter is about 51 118 km, that is, 4 superior to the Earth s equatorial diameter. Its temperature rounds the -216 ºC. It has a 12 hours and 14 minutes rotation and its translation 84 years and 4 days. Uranus is about 2 870 000 000 km from the Sun. Orbital period - 30799,095 days Average orbital velocity - 6,81 km/s Natural satellites - 27 Equatorial diameter - 51 118 km Surface area- 8,1156 10 9 km² Volume- 6,833 10 13 km³ Mass - 8,6810 10 25 kg Average temperature- -220,2 ºC Composition by mass: Hydrogen (83%), Helium (15%), Methane (1,99%) and, in a small quantity, Ammonia ethane and acetylene.

Neptune is the 8th planet of the Solar System. It s the 4th biggest planet in diameter and the 3th regarding mass. Neptune is 17 times the Earth s mass. Its rotation lasts 16 hours and 7 minutes and its translation approximately 165 terrestrial years. With 4 main rings and 13 natural satellites, its average temperature rounds the -193 ºC. Its atmosphere is mainly constituted by hydrogen. Neptune is about 4.504.300.000 km from the Sun. Orbital period - 60148,542 days Average orbital velocity - 5,4778 km/s Natural Satellites- 13 (the biggest is Triton) Equatorial diameter- 49 572 km Surface area - 7,65 10 9 km² Volume- 6,254 10 10 km³ Mass - 1,024 10 26 kg Temperature variation - -220,15 ºC Composition by mass: Hydrogen (85%) ; Helium (13%); Methane (2%)

I reached the conclusion that the Solar System appeared due to the Big-Bang, which was a big explosion that originated the Universe. The Solar System is constituted by planets, satellites and other fragments of space the orbit around the Sun. The planets are celestial bodies which don t have their own light and orbit around the Sun. The asteroids are rocks that travel through space with a big velocity. Comets also travel through space and have a core of ice and a tale.