Interesting Solar System facts
Discovery of the Solar system
People have been observing an annual path of the Sun in the Sky, changing face of the Moon, wandering bright stars – planets, tailed comets, visitors of the sky, and arrows of meteorites attacking Earth at night from the early time of Sumerians and Egyptians. We can consider regularly observations of above-mentioned natural phenomena to be discovery of the Solar system. In fact, its structure has been very mysterious prior to Copernicus time and only this Polish scientist put Sun to the respectful place – center of the system. Another enlightened person of the New Age Johannes Kepler explored planet orbits. Italian scientist Galileo Galilee having noticed satellites of Jupiter, Sun–spots, Venus periods and most probably Saturn rings, understood that the structure of Solar system is much more complicated. Indeed it consists of the Sun and heavenly bodies’ orbiting round the Sun in its gravitation field, i.e. planets, their satellites, thousands of small planets – asteroids, dusty iced pieces – comet nuclei, incalculable abundance of fine rock splinters – meteoroids, dust, single molecules and atoms. The whole Solar system is penetrated by electromagnetically radiation of the Sun and continuation of its atmosphere – torrent of electric particles, the so called Sun wind and artificial human made cosmic apparatus.
What is Solar system (Sun suite)
Five from eight planets surrounding the Sun can be seen with the naked eye. They are known from of old. They are Mercury, Venus, Mars, Jupiter and Saturn. Another three have been discovered through telescope. 1781 English astronomer William Herschel discovered Uranus, 1846 German Johann Galle discovered Neptune and 1930 American Clyde Tombaugh discovered Pluto. Many failed to discover the tenth planet afterwards, although there was much arguing and quarrelling that it still exists. Some of scientists were searching for it near to the Sun with its revolution closer than the Mercury; other scientists investigated the outer side of Pluto orbit. The truth is that later on many small planets–coperoids have been discovered at the edges of Solar system. Their discovery dethroned Pluto and it lost planet status in the XXI century.
The mass of all Solar system bodies is equal to 1,992×1030 kg. The most part of it 99, 85 % of material is concentrated in the system center, the Sun, which causes the revolution of heavenly bodies around.
Eight Solar system planets are grouped into two groups: outer great planets or the Jupiter group and interior small planets or the Earth group. Jupiter group consists of Jupiter, Saturn, Uranus and Neptune, Earth group consists of Mercury, Venus, Earth and Mars. Two planet groups are nicely divided in space by 1 astronomical unit (distance from Earth to the Sun, i.e. 150 000 000 million km) broad asteroid belt, located in between Mars and Jupiter orbits. Here you find tenths of thousands of small planets – asteroids; the biggest one is named Ceres with 960 km in equator line, discovered in 1801. Planets giants are accompanied by the suite of big and small natural satellites. Earth has only one satellite, Mars – two dwarf satellites, Jupiter even 63 satellites as known in spring 2009, Saturn – 61, Uranus – 27 and Neptune -13 satellites. All planets orbit round the Sun in direction of its rotation, their orbit planes are in close proximity to the Sun equator plane. This is a proof of the common formation mechanism of the Sun and its planets. Supposedly the Sun with its whole suite has been formed 5 milliards years ago from the rotating cloud of cosmic gases and dust.
This hypothesis is certified by lately found flattened gas and dust discs, covering stars just lighting up.
Similarly to planets most of cosmic rocks – asteroids are moving. Comets make something different – they shoot Sun possessions in various directions. To cap it all comets are flying in very elongated orbits, some of them move away from the Sun even tenth of thousands of astronomical units. Sun is able to get back them from this distance indeed. It is supposed that the Solar system is enshrouded by spherical comet nuclei – cluster Oort comet cloud from all sides. Possibly Sun would appear surrounded by glacial aerosols from neighboring stars.
How big are the Sun possessions?
The Sun’s domination stops where its pull is equal to the pull of the nearest stars. This so called neutral zone is approximately 100 000 astronomical units away from the Sun. The Sun light shaft gets over this distance during 1,5 years losing its warmth. The Sun would be only a yellowish brightly glaring dot from this distance. Other astronomers make the Solar system much smaller – they affirm the Neptune orbit shall be considered as the boundary. It this case the system diameter would shrink to 60 astronomical units. Third group of scientists suppose that the limits of the Solar system should be defined by the Heliosphere, which exists because of Solar wind, plasma flux of electrical particles. Behind the Neptune orbit it gets a lot weaker, because of meeting with pressure of interstellar dust and gas. 2007 cosmic apparatus “Voyager 2” discovered the boundary behind which no Solar wind exists at 85 astronomical units. It is amusing that this distance is most probably not stabile; the size of Heliosphere depends on the solar activity. So it is impossible to speak about concrete diameter of the Solar system. Sunlight gets to the Neptune within 5 hours. The closest star Centauri Proxima beams arrive to the Earth within 4,2 of the year. Consequently the distance to this star is 3350 times longer than from one edge of the Solar system to another. If a man would observe the Solar system from this star, the angular diameter of the Solar system would be not bigger than one arc minute. That is why even the world’s biggest telescopes are in trouble to discern planets of other stars.
The Solar system as a member of the Milky Way galaxy is two times younger than the latter. The Sun is one of 250 milliards Milky Way galaxy stars. It orbits accompanied with its planets around the Galaxy center, 28 000 Light-years away from it. The Sun makes one circle in 230 million years flying at 220 km/s velocity. This period of time is called a Galactic year. It is true to say that the Solar system is only 21 Galactic years old.
Cosmic apparatus have already visited all 8 Sun planets, investigated their atmospheres, and took pictures of their surfaces and satellites. 12 astronauts were walking on the surface of the Moon in 1969-1972. Several asteroids (Ida, Eros, and etc.) and comet nuclei (Halley’s Comet, Temple 1 and etc.) have been photographed from the near. Robots rolled down the surface of the Mars, plunged into the Venus, Jupiter’s Clouds (“Galileo”), Saturn satellite Titan (“Cassini”). Permanent residence settlements on the Moon are under design, their mission – to enable the longer duration of the flights in orbital stations, the mankind is planning a piloted flight to the Mars, and cosmic apparatus are travelling to the dwarf planets Ceres and Pluto. Some cosmic apparatus “Pioneer” and “Voyager” are flying far away on the other side of the Neptune towards the distant stars. If the speed of the cosmic research will not lose momentum, the commenced millennium shall become the epoch of the reclamation of the whole Solar system.
Interesting Solar System facts
The ancient Romans related planets seen with the naked eye, the Sun and the Moon with gods and days of the week
Sun day – Sunday
Moon day – Monday
Mars day – Tuesday
Mercury day – Wednesday
Jupiter day – Thursday
Venus day – Friday
Saturn day – Saturday
It is interesting that some languages retained reverberations of Roman myths. As you see in English we still use names of week days Sunday, Monday and Saturday.
Venus rotates around her axis to the opposite direction than all other planets of the Solar system, i.e. from the East to the West.
Scientists looking for a life in other planets (aliens) have much hope with the Mars, which has frozen ice and a thin atmosphere, Jupiter’s satellite Europe with icy shell under which the whole ocean is supposed to stretch out, Saturn’s satellites Titan wrapped itself up with a dense methane saturated atmosphere and the Enceladus gushing water geysers. The highest mountain found in Mars. Extinct Olympus volcano is even 27 km high above the usual average Mars surface.
Jupiter is worth to bear the name of the Chief Roman God. Its mass 2,5 times overcomes the mass of all other planets together! Alas, in comparison with the Sun it looks as the dwarf with the giant – the mass of our star is more than 1000 times bigger than the Jupiter’s. The Jupiter’s satellite Io is known for dozens of active volcanoes, more powerful than analogous volcanoes on the Earth.
Everybody has seen the photos of ringed Saturn. However, it is not the only planet with rings. Jupiter, Uranus, and Neptune have also rings.
All 27 Uranus satellites have been named after names of heroes from Shakespeare works.
Dwarf planet Pluto is smaller by size and mass in comparison with 7 planet satellites – Moon of the Earth, Ganymede, Callisto, Io and Europe of Jupiter, Titan of Saturn and Triton of Neptune. Ganymede is bigger than Mercury, so if it would have its own revolution around the Sun it would be considered another planet without any doubt.
About 10 years ago scientists knew only one planet system in the Universe – i.e. Solar system. Nowadays, in 2011, more than 550 planets orbiting round distant stars have been discovered! Indeed, one must admit that the modern technique hardly allows hunting down small planets of Earth type in the Universe.