The solar system is a set of planets and astronomical objects linked by the gravitational attraction produced by the single central star: the Sun. Within this planetary system there are a multitude of smaller bodies such as moons, dwarf planets, asteroids, meteoroids, centaurs , comets or cosmic dust. The planets of the solar system are Mercury, Venus, Earth.
Mars, Jupiter, Saturn, Uranus and Neptune. The solar system is 4. 568 billion years old and is located in the Milky Way.
If you start counting from the orbit of Pluto, it is estimated that it measures more than 5 billion kilometers. The closest known planetary system is Alpha Centauri, located about 4. 37 light years from our Sun.
In turn, the closest star would be Proxima Centauri, located about 4. 22 light years. The Sun is the largest and most massive object in the entire solar system, measuring no less than 2 x 10 30 kg and with a diameter of 1.
4 x 10 6 km. A million Earths comfortably fit inside. Analysis of sunlight shows that this huge sphere is composed mostly of hydrogen and helium, plus 2% of other heavier elements.
Inside there is a fusion reactor, which constantly transforms hydrogen into helium, producing the light and heat that it radiates. The Sun and the other members of the solar system probably originated at the same time, by the condensation of an original nebula of matter, at least 4. 6 billion years ago.
The matter in this nebula could well have come from the explosion of one or more supernovae. Although the Sun is not the largest or brightest star, it is the most important star for the planet and the solar system. It is a medium-sized star, quite stable and still young, located in one of the spiral arms of the Milky Way.
Fairly ordinary overall, but lucky for life on Earth. There are 8 planets in the solar system, classified into inner planets and outer planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. Inner Planets The inner planets are Mercury, Venus, Earth, and Mars.
They are small, rocky planets, while the outer planets like Jupiter are gas giants. This difference in density has its origin in the way the matter of the original nebula condensed. The farther from the Sun, the temperature decreases and, therefore, the matter could form different compounds.
In the vicinity of the Sun, where the temperature was higher, only heavy elements and compounds such as metals and silicates were able to slowly condense and form solid particles. Thus arose the dense planets: Mercury, Venus, Earth and Mars. Outer Planets The outer planets are Jupiter, Saturn, Uranus and Neptune.
They formed in more distant regions , in which matter rapidly condensed into ice. The rapid growth of these ice accumulations gave rise to objects of enormous size. However, inside these gigantic planets are not frozen, in fact they still radiate a large amount of heat into space.
The border between the inner and outer planets is the Asteroid Belt, remains of a planet that did not form due to the enormous gravitational pull of Jupiter, which dispersed them. Is Pluto a planet in the solar system? For a long time Pluto was considered a planet until 2006, when astronomers designated it as a dwarf planet due to its lack of orbital dominance, one of the characteristics that a celestial body must have to be considered a planet.
This means that in its environment there should be no other bodies of a similar size and with similar gravity. This is not the case of Pluto, whose size is similar to that of its moon Charon and very close to each other. Main characteristics of each planet The planets orbit around the Sun following elliptical orbits, according to Kepler's laws .
These orbits are all approximately in the same plane, which is the ecliptic plane, on which the movement of the Earth takes place around the Sun. In this figure you can see the orbits of the planets: Let us now see the main characteristics of each planet. - Mercury It is a small planet, barely larger than a third of the Earth and the closest to the Sun.
Rocky formations similar to those of the Moon can be seen on its surface, as can be seen in the images. Typical are the lobed scarps that astronomers say are an indication that Mercury is shrinking. It also has other characteristics in common with our satellite, for example the chemical composition, the presence of ice at the poles and a large number of impact craters.
Occasionally Mercury is visible from Earth, very low above the horizon, just at sunset or very early, before sunrise. This small planet has coupled its rotation and translation movement around the Sun, thanks to the so-called tidal forces. These forces tend to slow down the rotation speed of the planet around its axis, until equal to the speed of translation.
- Venus In size, mass and chemical composition, Venus is very similar to Earth, however its dense atmosphere prevents heat from escaping. This is the famous greenhouse effect, which is why the surface temperature of Venus reaches 400 ºC, close to the melting point of lead. The Venusian atmosphere is composed mainly of carbon dioxide and traces of other gases such as oxygen.
Atmospheric pressure is about 100 times greater than Earth's and the distribution of fast winds is highly complex. Another detail of the remarkable atmosphere of Venus is its rotation around the planet, which takes about 4 Earth days. Note that the rotation of the planet itself is extremely slow: one Venusian day lasts 243 Earth days.
Venus is abundant in deuterium, an isotope of hydrogen that is due to the lack of an ozone layer that protects against ultraviolet rays from the Sun. There is no evidence of water today, however, so much deuterium indicates that Venus may have had it in the last. - The Earth The third planet in proximity to the Sun is the only one that harbors life, at least as far as we know.
The Earth is at an ideal distance for life to proliferate and also has a protective ozone layer, abundant liquid water (up to 75% of the surface is covered by this element) and an intense magnetic field of its own. Its rotation is also the fastest of the four rocky planets. The Earth's atmosphere is composed of nitrogen and oxygen, with trace amounts of other gases.
It is stratified, but its limits are not defined: it progressively thins until it disappears. Another important feature of the Earth is that it has plate tectonics, which is why its surface undergoes changes continuously (in geological times of course). Hence, the evidence of craters that abound in the other planets of the solar system have already been erased.
This gives the Earth a wide variety of environmental settings: mountains, plains and deserts, along with an abundance of water, both in the vast oceans and in fresh water on the surface and subsoil. Along with the Moon, its natural satellite, it forms a remarkable duo. The size of our satellite is relatively large compared to that of the Earth and exerts a significant influence on it.
To begin with, the Moon is responsible for the tides, which exert a powerful influence on life on Earth. The Moon rotates synchronously with our planet: its periods of rotation and translation around the Earth are the same, which is why it always shows us the same face. - Mars Mars is slightly smaller than Earth and Venus, but larger than Mercury.
Its areal density is also somewhat lower. Very similar to Earth, the curious always thought they saw signs of intelligent life in the reddish star. The reddish color of Mars is due to the abundance of iron oxides on the surface.
As for its atmosphere, it is thin and consists of 95% carbon dioxide, with traces of other elements such as argon. There is no water vapor or oxygen. The latter is found forming compounds in rocks.
Unlike Earth, Mars does not have its own magnetic field, so the particles of the solar wind directly affect the surface, little protected by the thin atmosphere. As for the orography, it is varied and there are indications that the planet once had liquid water. One of the most notable features is Mount Olympus, the largest known volcano in the Solar System so far.
Mount Olympus far exceeds the largest volcanoes on Earth: it is triple the height of Mount Everest and 100 times the volume of Mauna Loa, the largest volcano on Earth. Without tectonic activity and with low gravity, the lava could accumulate to give rise to such a colossal structure. - Jupiter It is undoubtedly the king of the planets due to its large size: its diameter is 11 times greater than Earth's and its conditions are also much more extreme.
It has a rich atmosphere crossed by fast winds. Jupiter's well- known Great Red Spot is a long-standing storm, with winds of up to 600 km/h. Jupiter is gaseous, so below the atmosphere there is no solid ground.
What happens is that the atmosphere becomes denser as the depth increases, until reaching a point where the gas is liquefied. Hence it is quite flattened at the poles, because of the rotation. Despite the fact that most of the matter that makes up Jupiter is hydrogen and helium -like the Sun-, inside it has a nucleus of heavy elements at a high temperature.
In fact, the gas giant is a source of infrared radiation, so astronomers know that the interior is much hotter than the exterior. Jupiter also has its own magnetic field, 14 times stronger than Earth's. A notable feature of that planet is the large number of natural satellites it has.
Due to its enormous size, it is natural that its gravity has been able to capture many rocky bodies that happened to pass through its vicinity. But it also has large moons, the most notable being the four Galilean moons: Io, Europa, Callisto and Ganymede, the latter being the largest of the solar system's moons. These large moons probably originated at the same time as Jupiter.
In their own right they are fascinating worlds, since in them there is the presence of water, volcanism, extreme weather and magnetism, among other characteristics. - Saturn Without a doubt, what is most striking about Saturn is its complex ring system, discovered by Galileo in 1609. Millions of ice particles make up Saturn's rings, perhaps the remains of ancient moons and comets that impacted the planet .
Some satellites of Saturn, called shepherd satellites, are responsible for keeping the orbit free and confine the rings to well-defined regions of the planetary equatorial plane. The equator of the planet is quite pronounced, being a very flattened spheroid due to low density and rotational movement. Saturn is so light that it could float in a hypothetical ocean large enough to contain it.
Another reason for the deformation of the planet is that the rotation is not constant, but rather dependent on latitude and other interactions with its satellites. As for its internal structure, the data collected by the Voyager, Cassini and Ulysses missions ensure that it is quite similar to that of Jupiter, that is, a gaseous mantle and a nucleus of very hot heavy elements. The temperature and pressure conditions make it possible for liquid metallic hydrogen to form, so the planet has its own magnetic field.
Towards the surface, the weather is extreme: storms abound, although not as persistent as those on neighboring Jupiter. - Uranus The movement of Uranus is quite peculiar, being retrograde rotation, like Venus. In addition, the axis of rotation is very inclined with respect to the plane of the orbit: 97.
9º, so it practically rotates on its side. So the planet's seasons - revealed through the Voyager images - are quite extreme, with winters lasting 21 years. The blue-green color of Uranus is due to the methane content of its atmosphere, which is much cooler than that of Saturn or Jupiter.
But little is known about its internal structure. Both Uranus and Neptune are considered ice worlds, or rather gaseous or quasi-liquid. Although Uranus does not produce metallic hydrogen because of its lower mass and pressure in the interior, it does have a strong magnetic field, more or less comparable to Earth's.
Uranus has its own ring system, although not as magnificent as Saturn's. They are very faint and therefore not easily seen from Earth. They were discovered in 1977, thanks to the temporary occultation of the planet by a star, which allowed astronomers to see their structure for the first time.
Like all the outer planets, Uranus has many moons. The main ones are Oberon, Titania, Umbriel, Ariel and Miranda, names taken from the works of Alexander Pope and William Shakespeare. Frozen water has been detected on these moons.
- Neptune In the confines of the solar system is Neptune, the planet farthest from the Sun. It was discovered due to unexplained gravitational disturbances, which led to the existence of a large object not yet discovered. Seen from Earth, Neptune is a small blue-green dot, and until recently, little was known about its structure.
The Voyager mission provided new data in the late 1980s . The images showed a surface with evidence of strong storms and fast winds, including a large spot similar to that of Jupiter: the Great Dark Spot. Neptune has a methane-rich atmosphere, as well as a faint ring system, similar to that of Uranus.
Its internal structure is composed of an ice crust that covers the metallic core and has its own magnetism. As for the moons, about 15 have been discovered to date, but there could be a few others, since the planet is very far away and is the least studied yet. Triton and Nereid are the main ones, with Triton in retrograde orbit and possessing a tenuous nitrogen atmosphere of its own.
But the solar system does not only have planets, it also has other astronomical objects. We are talking about dwarf planets, moons or satellites of the larger planets, comets, asteroids and meteoroids. Each one has extremely interesting peculiarities.
Dwarf planets In the asteroid belt between Mars and Jupiter, and beyond the orbit of Neptune, in the Kuiper belt, there are many objects that, according to astronomical criteria, do not fall into the category of planets. The most outstanding are: - Ceres, in the asteroid belt. - Pluto, which was previously considered the ninth largest planet.
- Eris, discovered in 2003 and larger than Pluto and further from the Sun than this. - Makemake, in the Kuiper belt and about half the size of Pluto. - Haumea, also in the Kuiper belt.
It is markedly ellipsoidal in shape and has rings. The criterion to distinguish them from the larger planets is both their size and the gravitational attraction they possess, linked to their mass. To be considered a planet, an object must rotate around the Sun, as well as be more or less spherical.
And its gravity has to be high enough to absorb the other smaller bodies around it, either as satellites or as part of the planet. As at least the gravitational criterion is not met for Ceres, Pluto and Eris, this new category was created for them, to which Pluto went in 2006. In the distant Kuiper belt it is possible that there are more dwarf planets like these, still undetected.
Moons The major planets, and even Pluto, have satellites that orbit around them. There are more than a hundred belonging to the major planets, almost all distributed in the outer planets and three belonging to the inner planets: the Moon of the Earth, and Phobos and Deimos of Mars. There may still be more moons to discover, especially on planets farthest from the Sun, such as Neptune and other icy giants.
Their shapes are varied, some are spheroidal and others quite irregular. The largest probably formed next to the parent planet, but others could be captured by gravity. There are even temporary moons, which for some reason are captured by the planet but are eventually released.
Other bodies, in addition to the major planets, also have moons. It is estimated that so far there are about 400 natural satellites of all kinds. Comets Comets are debris from the cloud of matter that gave rise to the solar system.
They are made up of ice, rocks and dust and are currently found on the outskirts of the solar system, although they do come close to the Sun from time to time. There are three regions that are very far from the Sun, but still belong to the solar system Astronomers believe that there all the comets dwell: the Kuiper belt, the Oort cloud and the scattered disk. Asteroids, centaurs and meteoroids Asteroids are rocky bodies smaller than a dwarf planet or a satellite.
Almost all of them are found in the asteroid belt that marks the border between the rocky and gas planets. For their part, centaurs receive this name because they share characteristics of asteroids and comets, as do the mythological beings of the same name: half human and half horse. Discovered in 1977, they have not been properly imaged yet, but are known to be abundant between the orbits of Jupiter and Neptune.
Finally, a meteoroid is a fragment of a larger object, such as those described so far. They can be as tiny as a wisp of matter—not as small as a grain of dust—as small as 100 microns, or as large as 50 km in diameter.
