Planets in the Solar System

In our solar system there are eight planets, their satellites and satellites, all running around the sun. The eight planets are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. Pluto was once the ninth planet, but the IAU changed the planetary definition Pluto does not meet the standards, so it is now a dwarf. Mercury is the first planet closest to the sun. It is the smallest planet in the solar system. Mercury spun three times in two years. Mercury's day is very slow, so it corresponds to 176 Earth Day.

Mercury is one of the four planets of the solar system and is a rock like the earth. It is the smallest planet in the solar system with an equatorial radius of 2,439.7 kilometers (1,516.0 mi). Mercury is also smaller than the largest natural satellite in the solar system, Ganymede and Titan, but it is larger than that. Mercury is composed of about 70% metal and 30% silicate. The density of Mercury is the second highest in the solar system, 427 g / cm 3, slightly lower than the density of 515 g / cm 3 of the Earth. When the effect of gravity compression is resolved from the two planets, the material that makes mercury becomes deeper than the material of the earth, and it becomes 3 g / cm 3 uncompressed density against 4 g / cm 3 of the earth.

The slope of any planet in the solar system on the Mercury axis is minimal (about 1/30 degree). The eccentricity of its orbit is the largest among all the planets known for the solar system, and recently the distance between Mercury and the sun is only two thirds (or 66%) of the distance from the apogee. The surface of Mercury looks very slippery and resembles the surface of the moon. This indicates that it was geologically inactive for billions of years. There is hardly any atmosphere to maintain heat, its surface temperature changes day and night on any other planet in the solar system, and it changes from 100 K (-173 ° C; -280 ° F) to 700 K (427 ° C) Of the range. 800 ° F) Cross the equator during the day. Polar range is always less than 180 K (-93 ° C; -136 ° F). This planet does not have a known natural satellite.

Unlike other solar systems in the observable universe, Jupiter is too far from the main sun. Jupiter is the largest planet in the solar system and has great gravity. In other solar systems, increasingly larger planets are usually closer to their main star than small ones. However, in our solar system Mercury is closest to the sun, so the solar system draws a distinction from the others. In 1995, we found out that the extrasolar planet 51 Pegasi b is the major star on orbit around the Pegasus constellation about 50 light years later. It is half the size of Jupiter, but it is about 20 times closer to the earth than the earth in the sun. 51 Planets like Pegasi b are often called "hot Jupiter" and can be used in other solar systems, but our solar system mysteriously disappeared.