Our planets, the Sun and the Moon.

he Earth has, apart from the Moon and the Sun, a number of companion planets, from which the most known are since the age of time: Venus, Mars and Jupiter. The latter are thus in all astrological and religious cults. As we all know, the planets Mercury, Saturn, Uranus and Neptune, and the mini planet Pluto were discovered much later. Only a few clay tablets are exceptions, including those that show a Sun with ten planets. The former were not only aware of our solar system, but had already promoted the asteroid “Ceres” of being a planet. We have done this too, not long ago, by degrading the status of Pluto from planet to mini planet and offering “Ceres” the promotion from asteroid to mini planet. We find ourselves using this new classification with a solar system having eleven planets, including three mini planets, where it should be remembered that one of the latest discoveries was named after a figurine of a television series named “Xena.” This mini globe has since received the official name of “Eris”, which also has, like Pluto does, a moon.

The Sun:

The Sun is obviously our main star. The Sun contains in itself more than 99% of the total mass of the solar system and which is 328'900 times that of Earth. It has an instable orbit of about 226 million years around the center of our galaxy and travels around it with a speed of 217 km / sec at a distance of around 25'000 light years. Its average density is 1.4 kg/dm³ and the density at the center is 150 kg/dm³. The gravity at its surface is twenty-eight times that of Earth. The surface temperature is 5'500° Centigrade and at the center 14'000'000°. Then it takes 617 km / sec to escape its gravity. The Sun is composed primarily of hydrogen with 24.85% of helium and still some other elements, including oxygen, carbon, iron, neon, nitrogen, silicon, magnesium and sulfur.

The Moon:

The Moon is, as we all know, a satellite of the Earth. It makes a complete revolution in 27.32 days, turning the same face to Earth. We can see the full moon every 29.53 days, because it has to do a little more than one complete revolution to be in front of us again. The Moon is at an average distance of 384'403 km of the Earth and rotates with a speed of 1.03 kilometers per second around it, its size is 27% of the Earth and its mass is 1.22 % of that of the Earth.

Mercury:

The planet Mercury is the first planet from the Sun. It revolves around the Sun in 87 days and 15 hours at a distance of 0.39 AU¹ and its mass is 6% of the Earth. Its orbital velocity, the highest of all the planets, is 47.89 km / sec. It's not great either, because it measures just 39.4% of the size of the Earth. Moreover, a day on Mercury is longer than on Earth, ie 1'408 hours. Then to spend a day on this planet, which always turns the same face towards the sun, we will face very strong changes in temperature from 427° centigrade side to the Sun and minus 173° on the far side. It should be noted that the planet Mercury has virtually no atmosphere, even if traces of hydrogen and helium have been found there.

Venus:

The planet Venus is the second planet in our solar system. It revolves around the Sun in 226 days and 7 hours at a distance of 0.72 AU with a speed of 35 km / sec. Its mass is 82% of the Earth. It is slightly smaller than Earth (95%). A day on Venus lasts significantly longer than on Earth because it's 5'832 hours or 243 days! In addition to these very long days, the planet Venus has other peculiarities, one of which is the surface temperature, which is 453° Centigrade with a pressure of 90 bar and an atmosphere composed mainly of carbon dioxide with 3 % nitrogen and very little water and mostly dust. Another curiosity of Venus is that it's the only planet that rotates on itself in the opposite direction of others!

Mars:

The planet Mars is the fourth planet of our solar system. It revolves around the Sun in 686 days and 15 hours at a distance of 1.52 AU with a speed of 24 km / sec. Its mass is 11% of the Earth. It's much smaller than the Earth because its size is 53% of the Earth. A Martian day is, however, about the same as on Earth, ie around 24 hours. The surface temperature on Mars ranges from 37° to minus 123° Centigrade. The atmosphere at very low pressure is about the same as Venus, mostly carbon dioxide with 3% nitrogen, 1.6% argon, a little water and a little dust, mainly iron oxide. Its density is a special feature, while the other planets, Mercury, Venus and Earth have a density roughly similar ± 5.4 kg/dm³, Mars has a density of 3.95 kg/dm³, which is significantly lower than the other three. We can therefore assume that the iron core, like the Earth has one, is absent, or at least very small. Mars also has two moons, which are also fairly modest in size.

Jupiter:

The planet Jupiter is the fifth planet of our solar system and is the first of the four gas giants. It's not only the first of the giants, but also the largest of all the planets. It revolves around the sun in 11 years and 314 days at a distance of 5.2 AU with a speed of 13 km / sec. Its mass is 317 times that of Earth. It rotates around its axis rather quickly, as it completes a lap in 9 hours and 55 minutes. Its surface temperature is 153° Centigrade below the freezing point and it has no solid surface. We are up today not certain whether the planet Jupiter contains a solid core, other than crystallized hydrogen and helium under enormous pressure at the center. Jupiter, where we can hardly speak of atmosphere is composed primarily of hydrogen with 10% helium and 0.7% methane. Its average density is, in despite the fact that it is mainly composed of gas, 1.3 kg/dm³. The planet Jupiter has some peculiarities, which it shares with other major giants. The first feature is his famous eye, the red task, which turns out, after checking with satellites, to be a storm lasting for several thousand years having a size as large as Earth. Another feature that it shares with Jupiter, is that Saturn has rings, running for an unknown reason in a perfect synchronous way around it. These rings, of a width of 7'000 km, is primarily a feature of Saturn, but Jupiter and Uranus also have, even if they remain invisible from Earth. These rings can only be observed with a satellite in the vicinity. Jupiter has, like any great planet has, moons, more than twenty-eight where some of them are the subject of further study.

Saturn:

The planet Saturn is the sixth planet in our solar system and is the second of the four gas giants. It's not only the second giant, but also the second largest of all the planets. It revolves around the Sun in 29 years and 168 days at a distance of 9.5 AU with a speed of 9.6 km / sec. Its mass is 95 times that of Earth. It rotates around its axis as quickly as Jupiter, because it makes a turn in 10 hours and 15 minutes. Its surface temperature is minus 185° Centigrade and it has as Jupiter no solid surface. We are to date not certain whether Saturn contains, like Jupiter, a solid core, other than crystallized hydrogen and helium under enormous pressure at the center. Saturn, like Jupiter, where we can hardly speak of atmosphere, is primarily composed of hydrogen with 3% helium and 0.05% methane. Its average density is, in despite the fact that it's mainly composed of gases, 0.7 kg/dm³. It shares the distinction of Jupiter to have rings, which are the only ones to be visible from Earth. These rings look, like the one of the planet Jupiter, to rotate for some unknown reason in a perfectly synchronous way around Saturn. Saturn has, like Jupiter, moons, thirty of them.

Uranus:

The planet Uranus is the seventh planet of our solar system and is the third of four gas giants and is the smallest of the four. It revolves around the Sun in 84 years and 4 days at a distance of 19.2 AU with a speed of 6.8 km / sec. Its mass is 14.5 times that of Earth. It rotates around its axis more slowly than Jupiter, because it makes a turn in 17 hours and 14 minutes. Its surface temperature is 214° Centigrade below the freezing point and it has as Jupiter no solid surface. Like Jupiter, we do not know if Uranus has a solid core, other than crystallized hydrogen and helium. Uranus, like Jupiter, where we can hardly speak of an atmosphere, is composed primarily of hydrogen with 15% helium and 2% methane. Its average density is, in despite the fact that it is mainly composed of gases, 1.3 kg/dm³. It shares the distinction of Jupiter to have rings, which are, like Jupiter, invisible from Earth. Uranus has as it should be twenty-four moons.

Neptune:

The planet Neptune is the eighth planet in our solar system and is the fourth and most distant of the four gas giants. It revolves around the Sun in 164 years and 289 days at a distance of 30 AU with a speed of 5.4 km / sec. Its mass is 17.1 times the Earth. It rotates around its axis more slowly than Jupiter, because it makes a turn in 16 hours and 3 minutes. Its surface temperature is minus 225° Centigrade and it has as Jupiter no solid surface. We do also not know if Neptune, like Jupiter, has a solid core, other than crystallized hydrogen and helium. Neptune, like Jupiter, where we can hardly speak of an atmosphere, is composed primarily of hydrogen with 25% helium and 1% methane. Its average density is, in despite the fact that it is mainly composed of gases, 1.7 kg/dm³. It shares with Jupiter and Saturn to have rings, which are, like Jupiter, not visible from Earth. And as all big planets, it also has eight moons.

Pluto and Eris:

The mini planets Pluto and Eris, rather small because they are barely a fifth of the Earth, are located at a distance of 39.5 AU and 97 AU from the Sun. They both have a moon. Then they have, because of their remoteness, rather long orbits. The one of Pluto is 248 years and 560 years for Eris. Even if we don't know the surface temperature of Eris, that Pluto is rather low, minus 236°. We don't know if they have an atmosphere. Perhaps that Pluto would have an atmosphere composed of methane and nitrogen, but this is not clear at this time.

Apart from Pluto and Eris, we still found other mini-planets in a size of two-thirds of Pluto at a distance of 52 AU, with orbits ranging from 285 years to 307 years. These two mini-planets have yet received the very poetic names of “2003EL61” and “2005FY9.”

Asteroids and comets:

We have over one hundred forty thousand objects that have, for the most part, their orbits between the planets Mars and Jupiter. We don't know to this day if a planet had never formed there, or if all these objects are the debris of a destroyed planet. It's quite conceivable that it's the gravity of the planet Jupiter which has prevented the formation of an additional planet. While most asteroids have a very distant orbit of the Earth, there are others whose orbit crosses regularly those of other planets. It's only a matter of time and circumstances that an accident will occur. It's for this reason that we should not overlook the importance of a planetary alignment, such as those at the time of the destruction of Atlantis.

Comets are objects similar to asteroids, with the only difference that comets are objects of an area that we call the ring of Kuiper better known as “Kuiper Belt”. Most items in this area never leave the area, but some, like a number of asteroids, have rather asymmetric orbits which cross the orbits of the planets at intervals ranging from less then a hundred to several thousand years. We have seen an example of such an encounter, with the crash of comet Shoemacher-Levy on Saturn. The impact generated by this event was as big as the Earth itself. The danger of these objects lies in the fact that we don't know them. The great danger of such objects, which are emerging from time to time, without that we can measure the details of their orbits, is that the time required to calculate their trajectories is very limited. In addition, the chance that one of them could score the bull's eye is only a matter of time, or circumstances, such an alignment of planets.