What is solar system and its some facts

1) The hottest planet isn’t closest to the sun.Many people know that Mercury is the closest planet to the sun, well less than half of the Earth’s distance. It is no mystery, therefore, why people would assume that Mercury is the hottest planet. We know that Venus, the second planet away from the sun, is on the average 30 million miles farther from the sun than Mercury. The natural assumption is that being farther away, it must be cooler. But assumptions can be dangerous. For practical consideration, Mercury has no atmosphere, no warming blanket to help it maintain the sun’s heat. Venus, on the other hand, is shrouded by an unexpectedly thick atmosphere, about 100 times thicker than our own on Earth. This in itself would normally serve to prevent some of the sun’s energy from escaping back into space and thus raise the overall temperature of the planet. But in addition to the atmosphere’s thickness,The carbon dioxide freely lets solar energy in, but is far less transparent to the longer wavelength radiation emitted by the heated surface. The maximum temperature on Mercury, the planet closer to the sun, is about 800 degrees F. In addition, the lack of atmosphere causes Mercury’s surface temperature to vary by hundreds of degrees, whereas the thick mantle of carbon dioxide keeps the surface temperature of Venus steady, hardly varying at all, anywhere on the planet or any time of day or night!

2) Pluto is smaller than the USA.The greatest distance across the contiguous United States is nearly 2,900 miles (from Northern California to Maine). By the best current estimates, Pluto is just over 1400 miles across, less than half the width of the U.S. Certainly in size it is much smaller than any major planet, perhaps making it a bit easier to understand why a few years ago it was “demoted” from full planet status. It is now known as a (dwarf planet.)

3) George Lucas doesn’t know much about (asteroid fields.)In many science fiction movies, spacecraft are often endangered by pesky asteroid fields. In actuality, the only asteroid belt we are aware of exists between Mars and Jupiter, and although there are tens of thousands of asteroids in it (perhaps more), they are quite widely spaced and the likelihood of colliding with one is small. In fact, spacecraft must be deliberately and carefully guided to asteroids to have a chance of even photographing one.

4) You can make volcanos using water as magma. Mention volcanoes and everyone immediately thinks of Mount St. Helens, Mount Vesuvius, or maybe the lava caldera of Mauna Loa in Hawaii. Volcanos require molten rock called lava (or “magma” when still underground), right? Not really. A volcano forms when an underground reservoir of a hot, fluid mineral or gas erupts onto the surface of a planet or other non-stellar astronomical body. The exact composition of the mineral can vary greatly. On Earth, most volcanoes sport lava (or magma) that has silicon, iron, magnesium, sodium, and a host of complicated minerals. The volcanoes of Jupiter’s moon Io appear to be composed mostly of sulfur and sulfur dioxide. But it can be simpler than that. On Saturn’s moon Enceladus, Neptune’s moon Triton, and others, the driving force is ice, good old frozen H₂0! Water expands when it freezes and enormous pressures can build up, just as in a “normal” volcano on Earth. When the ice erupts, a (cryovolcano) is formed. So volcanoes can operate on water as well as molten rock. By the way, we have relatively small scale eruptions of water on Earth called geysers.

5. The edge of the solar system is 1,000 times farther away than Pluto. you might still think of the solar system as extending out to the orbit of the much-loved dwarf planet Pluto. Today we don’t even consider Pluto a full-fledged planet, but the impression remains. Still, we have discovered numerous objects orbiting the sun that are considerably farther than Pluto. These are “Trans-Neptunian Objects” (TNOs), or (Kuiper Belt Objects) "KBOs". The Kuiper Belt, the first of the sun’s two reservoirs of cometary material, is thought to extend to 50 or 60 astronomical units (AU, or the average distance of the Earth from the sun).