O Solar system, located in the galaxy Milky Way, consists of the setinplanets,planetsdwarvesand several other stars of the Universe, such as asteroids, meteors, comets, satellites, among others. O Sun it is the central star of this system, exerting an intense gravitational control over the other celestial bodies.
readalso:Biggest stars in the Universe
Origin
O Solar system formed about 4.7 billion years ago. However, your origin is still questioned, since there is no theory that fully satisfies all the questions that pervade the formation of the Sun and planets. However, currently, there is a theory more accepted among the scientific and astronomical community: the solar nebula theory.
This theory was initially formulated by Rene Descartes in the year 1644, being reformulated by Immanuel Kant in 1775 and, later, by Pierre-Simon de Laplace in 1796. The theory formulated by Laplace hypothetically supposed that the Sun formed from the rotation of a cloud that when contracting under the influence of gravity, increased its speed, thus entering into collapse. Thus, the sun formed due to the central concentration of the nebula and planets formed from the remnants of the collapsing molecular cloud.
The Solar System is believed to have arisen from the collapse of a nebula.
This theory was perfected, continuing to be based on the fact that the Sun and the planets were formed almost simultaneously. For theory, the Sol had its formation in the center of the nebula. The planets that formed in the outermost regions, where the temperature is lower and the volatile substances, condensed.
The planets formed in more internal regions, where the temperature is higher and the substances more volatile, were lost. this circumstance explains the classification of planets into gaseous and rocky.
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Know more: What is the Big Bang Theory?
How many planets are there in the Solar System?
Currently, the Solar System is officially constituted by eight planets and five dwarf planets.
The Solar System is composed of eight planets and five dwarf planets.
planets |
dwarf planets |
Mercury |
Ceres |
Venus |
Pluto |
Earth |
haumea |
Mars |
make make |
Jupiter |
eris |
Saturn | |
Uranus | |
Neptune |
knowmore:Curiosities about the Solar System
→ Pluto, a dwarf planet
Plutoit was considered a planet in the Solar System. However, the new astronomical discoveries confirmed the existence of bodies with characteristics similar to those of Pluto. This generated intense discussions about the classification of this star. Therefore, it would be necessary to either increase the number of planets in the Solar System or create a new classification for the Pluto-like celestial bodies.
Pluto is no longer considered a planet, but a dwarf planet.
Thus, in 2006, the International Astronomical Union (UAI), responsible for regulating the nomenclatures, definitions and classifications in Astronomy, presented a new concept for the word planet, “downgrading” Pluto, then, to the category of dwarf planet.
Definition of planet, according to the UAI:
“it is a celestial body that is in orbit around the Sun, it has enough mass for its self-gravity related to the forces of the body. rigid allow it to assume a shape in hydrostatic balance (round shape) and, has clean its surroundings along its orbit."
Definition of dwarf planet according to UAI:
is a celestial body that is in orbit around the Sun, has enough mass for its self-gravity related to rigid body forces. so that it assumes a form in hydrostatic equilibrium (approximately rounded.), it has not clean its vicinity along its orbit.""
Solar System Stars
In addition to the planets, there are Solar system other stars. According to the International Astronomical Union, with the exception of satellites that orbit the Sun, they should be designated such as: small bodies in the Solar System these bodies that have dimensions smaller than planets and planets dwarves.
They are, according to the Institute of Astronomy, Geophysics and Atmospheric Sciences:
Asteroids: bodies that have their own movement, most of which have already been cataloged, have elliptical orbits and are found in the asteroid belt between Mars and Jupiter. Its size can be calculated by measuring the amount of light it reflects. Only 16 asteroids, out of more than 3000 catalogued, have dimensions greater than 240 km. Its brightness is not constant due to solar reflection.
Comets: bodies made up of a solid part called the core which is formed by ice and impurities. Their shape is irregular, and they are quite extensive. They are composed especially of water, and as it approaches the Sun, the ice in the core suffers evaporation, ejecting dust grains that end up reflecting sunlight, thus giving the shiny appearance to the comet. They have tails, which are extensions of the cloud of gas and dust.
Meteors, meteoroids and meteorites:the meteor corresponds to the luminous phenomenon observed during the passage of a meteoroid in the atmosphere. Meteoroids correspond to the remains of comets or fragments from asteroids. Meteorites are meteoroids that survive by entering the atmosphere and hitting the ground.
Mind Map: Solar System
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planets
The eight planets in the Solar System are classified according to their position relative to the Sun. The order of the planets is:
Sun → Mercury → Venus → Earth → Mars → Jupiter → Saturn → Uranus → Neptune |
They can be classified into:
→ Telluric, terrestrial or rocky planets:are the four closest planets to the Sun: Mercury, Venus, Earth and Mars. They are characterized by being made up of rocks, iron and heavy metals and by having greater density, as dense materials tend to be closer to the Sun.
→Jovian, giant or gas planets: are the four planets farthest from the Sun: Jupiter, Saturn, Uranus and Neptune. They are larger than the telluric planets in terms of size. They are characterized by being formed by gases such as helium and hydrogen. They are less dense, so they are further away from the Sun. There is evidence that these planets have a rocky core, however, they do not have a defined surface. All feature multiple natural satellites and ring systems.
The main features of each planet are:
1. Mercury
Mercury is the closest planet to the Sun.
Mercury is the closest planet to the Sun. This planet is capable of reflecting about 12% of sunlight, making it one of the brightest stars seen on Earth. It is located about 57,910,000 km from the Sun.
Its surface is full of craters, while its core is rich in iron, and the planet's atmosphere is mostly composed of helium (98%) and hydrogen (2%). The planet's temperature during the day reaches 430ºC.
2. Venus
Venus is known as Star Dalva is one of the brightest stars in the night sky.
Venus it is the second planet in relation to the Sun, also known as Estrela D'alva, as it is often one of the brightest stars in the night sky. It lies approximately 108,200,000 km from the Sun. It has characteristics similar to those on Earth, such as size and mass, but differs in the conditions that support life.
It has an atmosphere 92 times denser than the Earth's atmosphere, and the planet is almost always surrounded by clouds. This atmosphere is composed especially of CO2, which contributes to the planet's temperature reaching 460ºC.
3. Earth
The Earth is the planet we live on and, until today, it is the only one with conditions for life to exist.
THE Earth it is the planet that most differs from the others, considering its conditions and characteristics that allow the existence of life. The planet is located at a favorable distance from the Sun, about 149,600,000 km. Its dynamism provided by solar radiation, tidal forces and the heat coming from its core make it a unique planet in the Solar System.
Its average temperature is 14ºC, and only 60% of the solar energy is absorbed. The Earth's atmosphere is currently composed of gases such as nitrogen, oxygen, carbon dioxide and water vapor. Its internal structure is composed of the Earth's core, mantle and crust. It has a natural satellite, the Moon, with rotation synchronized with the Earth.
readmore: Earth, the planet of life
4. Mars
Mars is the planet in the Solar System with the characteristics most similar to those of Earth.
Mars it is the fourth planet second in distance from the Sun. It lies approximately 227,940,000 km from that star. This planet has the most Earth-like climate, as well as its rotational movement.
The observation of its surface has led some scientists to consider possible existence of life forms on the planet. Its surface is characterized by the presence of craters and dust that is composed of magnetite, which gives the Martian soil a reddish color.
The planet's soil is rich in iron and silicon. The planet's atmosphere is thinner than Earth's, being made up especially of CO2, nitrogen, traces of oxygen, carbon monoxide and water vapor. Temperatures on the planet can vary between -76°C and -10°C.
5. Jupiter
Jupiter is the largest planet in the Solar System and is known as the gas giant.
Jupiter it is known as the “gas giant”, being the largest planet in the Solar System, in addition to the planet with the highest rotation speed. It is located approximately 778.330,000 km from the Sun. Its appearance presents shades of red, orange, brown and yellow.
Despite being the most massive planet, it is not the densest, as it is composed of gases, especially helium and hydrogen. The planet is believed to have a rocky core and it is unclear whether it has a defined surface. In the year 1979, they discovered that Jupiter had a ring system.
6. Saturn
Saturn is the planet known for its set of rings.
Saturn it is the second largest planet in the Solar System, being approximately 1,429,400,000 km from the Sun. The gas planet is known for its rings and it is believed that these are composed of ice, due to their intense brightness, which can reflect up to 80% of sunlight. The planet has a single large satellite known as Titan.
The planet's atmosphere is mainly made up of hydrogen and helium. The planet's density is much lower than Earth's because of its composition. There are indications that the planet has a solid core, as does Jupiter.
7. Uranus
The discovery of Uranus is one of the most recent, considering the planets in the Solar System.
Uranus is a low-light planet and lies about 2,880,990,000 km from the Sun. It has a smaller mass than Jupiter, but it has a denser core, which makes it possible to say that it may have a rocky core.
Uranus was discovered in 1781. The planet has rings that were discovered in 1977, and they are quite opaque to light. The planet has about 27 natural satellites and about 27 moons. Its atmosphere is composed of hydrogen, helium and methane, the latter being responsible for its bluish color. The temperature on the planet is approximately -218ºC.
8. Neptune
Neptune is the last planet in the Solar System, as well as being the last to be discovered.
Neptune it is the most recently discovered planet. His presence was noted in the year 1845. It is located approximately 4,504,300,000 km from the Sun. The planet has similar characteristics to Uranus in terms of mass and atmospheric composition. Its atmosphere is composed of hydrogen, helium and methane, and has an average temperature of -218ºC. Its interior is believed to be similar to that of Uranus as well.
Neptune has a ring system. In addition, it features thirteen satellites, its largest being known as Triton.
Curiosities
At most two hours before the sun rises or two hours before the sun sets, it is possible to see Mercury with the naked eye.
A day on Venus is longer than a year on Earth.
On Mars, there are several dormant volcanoes. The biggest one is known as Olympus Mons.
In 1971, the Mariner spacecraft, which took pictures of the planet's surface, was placed in orbit around Mars, showing details of up to one kilometer.
Jupiter has more than 60 small natural satellites.
Saturn has about 60 moons.
The presence of methane in Neptune's atmosphere gives it a bluish color.
Although Mercury is closest to the Sun, it is not the hottest. Venus is the one who occupies this position, as it has an atmosphere composed of CO2, which creates a kind of greenhouse effect on the planet, raising its temperature to over 460ºC.
by Rafaela Sousa
Graduated in Geography
