Mercury

Mercury is the first planet from the Sun and the smallest planet in the Solar System. It is a terrestrial planet with a heavily cratered surface due to the planet having no geological activity and an extremely tenuous atmosphere (called an exosphere). Despite being the smallest planet in the Solar System with a mean diameter of 4,880 km (3,030 mi), 38% of that of Earth's, Mercury is dense enough to have roughly the same surface gravity as Mars. Mercury has a dynamic magnetic field with a strength about 1% of that of Earth's and has no natural satellites.

According to current theories, Mercury may have a solid silicate crust and mantle overlying a solid outer core, a deeper liquid core layer.

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Venus

Venus is the second planet from the Sun. It is a rocky planet with the densest atmosphere of all the rocky bodies in the Solar System, and the only one with a mass and size that is close to that of its orbital neighbour Earth. Orbiting inferiorly (inside of Earth's orbit), it appears in Earth's sky always close to the Sun, as either a "morning star" or an "evening star". While this is also true for Mercury, Venus appears much more prominently, since it is the third brightest object in Earth's sky after the Moon and the Sun,[20][21] appearing brighter than any other star-like classical planet or any fixed star. With such a prominence in Earth's sky, Venus has historically been a common and important object for humans, in both their cultures and astronomy.

Venus has a weak induced magnetosphere and an especially thick carbon dioxide atmosphere, which creates, together with its global sulfuric acid cloud cover,

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Earth

Earth is the third planet from the Sun and the only place known in the universe where life has originated and found habitability. This is enabled by Earth being a water world, the only one in the Solar System sustaining liquid surface water. Allmost all of Earth's water is contained in its global ocean, spanning 70.8% of Earth's surface. The other 29.2% of Earth's surface is on land, consisting of continents and islands. While Earth's land is also covered by large amounts of water, mainly in the form of large sheets of ice covering polar land, containing more water than Earth's groundwater, lakes, rivers and atmospheric water together, most of Earth's land though is covered by vegetation. Below the planet's surface lies the crust, consisting of several slowly moving tectonic plates, which interact to produce mountain ranges, volcanoes, and earthquakes. Inside the Earth's crust is a liquid outer core that generates the magnetosphere, deflecting most of the destructive solar winds and cosmic radiation.

Earth has a dynamic atmosphere, which sustains Earth's surface conditions and protects it from most meteoroids and UV-light at entry Source

Mars

Mars is the fourth planet and the furthest terrestrial planet from the Sun. The reddish color of its surface is due to finely grained iron(III) oxide dust in the soil, giving it the nickname "the Red Planet" .Mars’s radius is second smallest among the planets in the Solar System at 3,389.5 km (2,106 mi). It has a surface gravity of 3.72 m/s2 (12.2 ft/s2), which is 38% of Earth's gravity. The Martian dichotomy is visible on the surface: on average, the terrain on Mars’s northern hemisphere is flatter and lower than its southern hemisphere. Mars has a thin atmosphere made primarily of carbon dioxide and two irregularly shaped natural satellites: Phobos and Deimos.

Geologically, Mars is fairly active, with dust devils sweeping across the landscape and marsquakes (Martian analog to earthquakes) trembling underneath the ground. The surface of Mars hosts a large shield volcano (Olympus Mons) and one of the largest canyons in the Solar System (Valles Marineris) . Source

Jupiter

Jupiter is the fifth planet from the Sun and the largest in the Solar System. It is a gas giant with a mass more than two and a half times that of all the other planets in the Solar System combined, and slightly less than one one-thousandth the mass of the Sun. Jupiter is the third brightest natural object in the Earth's night sky after the Moon and Venus, and it has been observed since prehistoric times. It was named after Jupiter, the chief deity of ancient Roman religion.

Jupiter is primarily composed of hydrogen (90% by volume) , followed by helium, which constitutes a quarter of its mass and a tenth of its volume. Source

Saturn

Saturn is the sixth planet from the Sun and the second-largest in the Solar System, after Jupiter. It is a gas giant with an average radius of about nine and a half times that of Earth. It has only one-eighth the average density of Earth, but is over 95 times more massive.

Saturn's interior is thought to be composed of an rocky core , surrounded by a deep layer of metallic hydrogen, an intermediate layer of liquid hydrogen and liquid helium, and finally, a gaseous outer layer . Saturn has a pale yellow hue due to ammonia crystals in its upper atmosphere. An electrical current within the metallic hydrogen layer is thought to give rise to Saturn's planetary magnetic field, Source

Uranus

Uranus is the seventh planet from the Sun and is a gaseous cyan ice giant. Most of the planet is made out of water, ammonia, and methane in a supercritical phase of matter, which in astronomy is called 'ice' or volatiles. The planet's atmosphere has a complex layered cloud structure and has the lowest minimum temperature of 49 K (−224 °C; −371 °F) out of all Solar System's planets. It has a marked axial tilt of 97.8° with a retrograde rotation rate of 17 hours. This means that in an 84 Earth years orbital period around the Sun, its poles get around 42 years of continuous sunlight, followed by 42 years of continuous darkness.

Uranus has the third-largest diameter and fourth-largest mass among the Solar System's planets. Based on current models, inside its volatile mantle layer is a rocky core Source

Neptune

Neptune is the eighth planet from the Sun and the farthest known planet in the Solar System . It is the fourth-largest planet in the Solar System by diameter, the third-most-massive planet, and the densest giant planet. It is 17 times the mass of Earth, and slightly more massive than its near-twin Uranus. Neptune is denser and physically smaller than Uranus because its greater mass causes more gravitational compression of its atmosphere. Being composed primarily of gases and liquids, it has no well-defined solid surface. The planet orbits the Sun once every 164.8 years at an average distance of 30.1 astronomical units (4.5 billion kilometres; 2.8 billion miles). It is named after the Roman god of the sea and has the astronomical symbol ♆, representing Neptune's trident. Source

The planets of our Solor system.