Planets – Physical Geography (UPSC)

Mercury is the smallest and the nearest planet to the Sun. It completes its revolution around the Sun in just 88 days. Composed of Nitrogen, Hydrogen, Oxygen, and Carbon Dioxide, Mercury has no water.
Venus is the hottest planet in the entire solar system, with surface temperatures reaching up to 478°C. It is often called Earth’s twin due to its similarity in size, mass, and density. Venus is the brightest planet in the solar system and is also referred to as the Evening Star and Morning Star. It rotates around the Sun in a clockwise direction.
Earth, the third planet from the Sun, is the only known planet to harbor life in all its forms. It is called the Blue Planet due to the abundance of water and has one natural satellite, the Moon.
Mars is known as the Red Planet because of its iron-rich red soil. It is the second smallest planet after Mercury and has dark patches on its surface. Mars has a thin atmosphere and features valleys, craters, deserts, and ice caps. It has two natural moons, Phobos and Deimos, and is the second planet after Earth to show signs of potential life. Mars is home to the largest known volcano and the second tallest mountain in the solar system, Olympus Mons.
Jupiter is the largest planet in the solar system. Its surface is made up of Hydrogen, Helium, and Methane and is known for its distinctive dark and lighter bands. Jupiter has 53 named moons, with another 26 awaiting official names. Its largest moon, Ganymede, was discovered by Galileo Galilei in 1610. Other moons include Io, Callisto, and Europa. Jupiter also has an unclear ring around it.
Saturn, the second largest planet, is entirely gaseous in nature and is easily recognizable by its three concentric rings. Saturn has 82 moons, with Titan being the largest. Saturn takes 29.5 Earth years to complete its orbit and can float on water due to its lower density than water.
Uranus also orbits the Sun in a clockwise direction, like Venus. It appears as a greenish-bluish disc through a telescope and is composed of Hydrogen, Helium, water, and ammonia. Uranus has at least 20 moons, including larger ones like Miranda, Ariel, and Titania.
Neptune is the farthest planet from the Sun and has a bluish color due to the presence of Methane. Along with Uranus, Neptune is referred to as an ice giant. Neptune was discovered through mathematical predictions and disturbances in Uranus’s orbit. It has about 14 moons, with Triton being the largest.

Key Facts About Planets in the Solar System

Mercury

• Smallest and closest planet to the Sun.
• Completes one revolution around the Sun in 88 days.
• Made up of Nitrogen, Hydrogen, Oxygen, and Carbon Dioxide, but no water.

Venus

• Hottest planet in the solar system with a surface temperature of 478°C.
• Called Earth’s twin due to similarities in size, mass, and density.
• Known as the Evening Star and Morning Star.
• Rotates around the Sun in a clockwise direction.

Earth

• Third planet from the Sun.
• The only planet with life in all its forms.
• Known as the Blue Planet because of water presence.
• Has one natural satellite called the Moon.

Mars

• Known as the Red Planet due to its iron-rich soil.
• Second smallest planet after Mercury.
• Surface features include valleys, craters, deserts, ice caps, and the Olympus Mons, the largest known volcano.
• Has two moons: Phobos and Deimos.
• The most promising planet for the possibility of life after Earth.

Jupiter

• Largest planet in the solar system.
• Made up of Hydrogen, Helium, and Methane.
• Features dark and light circular bands and has an unclear ring.
• Has 79 moons, including Ganymede, Io, Callisto, and Europa.

Saturn

• Second-largest planet and entirely gaseous.
• Known for its three concentric rings visible from Earth.
• Has 82 moons, with Titan being the largest.
• Takes 29.5 Earth years to complete its orbit and has a lower density than water.

Uranus

• Orbits the Sun in a clockwise direction, like Venus.
• Appears as a greenish-bluish disc through telescopes.
• Composed of Hydrogen, Helium, water, and ammonia.
• Has at least 20 moons, including Miranda, Ariel, and Titania.

Neptune

• Farthest planet from the Sun.
• Appears bluish due to the presence of Methane.
• Discovered via mathematical predictions and disturbances in Uranus’s orbit.
• Known as one of the Ice Giants and called a twin to Uranus.
• Has 14 moons, with Triton being the largest.