The inner planets are made of rocks and metals and are called the terrestrial planets. They are Mercury, Venus, Earth and Mars. As of 2014, Earth is the only terrestrial planet known to have life.Know More
Mercury is the closest inner planet to the sun. It has very little atmosphere and is pockmarked with craters. It's made mostly of iron and nickel and, like Earth, is believed to have a molten iron core. The crust of Mercury is made of silicates.
Venus is notorious both for its beauty in the morning and evening skies and also for its atmosphere, which is thick with clouds made of sulfuric acid. Venus also has an iron core, but it spins so slowly that the planet doesn't have a global magnetic field like Earth. Venus is so geologically active, with many volcanoes, that its surface features change constantly.
Earth is not only made of rocks and metals, but it is also covered in water, which allows it to support life.
The red soil of Mars indicates that the iron within it has oxidized. Mars might also have liquid water, but its atmosphere is so thin that the water probably sublimates, or turns directly from water to gas. Mars seems to have water ice at its poles.Learn more about Planets
The size difference between the Jovian and terrestrial planets in the solar system occurs because of the planets' proximity to the Sun and chemical composition. Jovian planets lie beyond the frost line, which separates the four terrestrial planets from the gaseous Jovian planets. Despite residing farther from the Sun, the Jovian planets have larger sizes than terrestrial planets due to their gaseous compositions and stronger gravitational fields, which help pull objects to their surfaces, ultimately increasing their sizes.Full Answer >
In addition to Earth, the terrestrial planets of Mars, Venus and Mercury have oxygen in their atmospheres. The atmospheres of these planets, along with the others in the solar system, contain many different substances. The amount of oxygen in their atmospheres varies; Earth contains the most oxygen while Mars and Venus have smaller amounts and more carbon dioxide.Full Answer >
Outer planets of the solar system are made predominantly of gases. They tend to have many more moons than the inner planets, and outer planets take a shorter period of time to rotate around their axes.Full Answer >
According to NASA, gravity is the reason why planets are round. Gravity causes any matter to attract toward any other matter. When planets began to form, the earth’s solar system was one big swirling disk that contained dust and gas, with the sun at its center. Particles of dust and gas pulled toward each other due to gravity.Full Answer >