Inner Planets: Mercury and Venus

Planets in the Solar System

• Eight planets constantly orbit the Sun at varying speeds.
• Planets rotate on their axes and reflect sunlight.
• Planets are classified as inner and outer.
• Inner planets are closer to the Sun, while outer planets are more distant.

Inner Planets (Terrestrial Planets)

• Mercury, Venus, Earth, and Mars are inner planets
• These planets feature rocky surfaces.

Mercury

• Mercury is the closest planet to the Sun.
• It is 58 million km from the Sun on average.
• Its equatorial diameter measures 4,880 km.
• It completes a revolution in 88 Earth days.
• Mercury's rotation period is 59 Earth days.
• Possesses a very thin atmosphere.
• Surface temperatures range drastically from 430°C (daytime) to -180°C (nighttime).
• Its surface is heavily cratered.
• Mercury has no moons or rings.

Venus

• Venus is the second planet from the Sun.
• Its average distance from the Sun is 108 million km.
• The equatorial diameter of Venus is 12,104 km.
• It rotates from east to west every 243 Earth days.
• Venus revolves around the sun in 225 days.
• Its atmosphere consists mostly of carbon dioxide.
• The surface temperature exceeds 470°C.
• Venus is the sky's brightest object, after the Moon.
• It has no moons or rings.

Earth

• Earth is the third planet from the Sun.
• Its average distance from the Sun is 149 million km.
• It is the only known planet capable of sustaining life.
• Earth's equatorial diameter is 12,750 km.
• Earth is known as the "Blue Planet".
• It completes a revolution in 365 and 1/4 days.
• Earth rotates every 24 hours.
• The atmosphere is composed of 77% nitrogen and 21% oxygen.
• The average surface temperature is 15°C.
• Land covers 1/3 of Earth's surface, while water covers 2/3.
• Earth has one moon, which orbits the planet every 27.3 days.

Mars

• Mars is the fourth planet from the Sun.
• It is 227 million km from the Sun on average.
• Known as the "Red Planet" due to iron-rich surface.
• Its equatorial diameter is 6,788 km.
• Mars has a thin, carbon dioxide-dominated atmosphere.
• Its average surface temperature is -63°C.
• Mars features volcanoes, including Mount Olympus.
• It revolves around the sun in 687 Earth days.
• Mars rotates in 24 Earth days.
• It has two moons.

Outer Planets (Jovian Planets)

• The outer planets are Jupiter, Saturn, Uranus, and Neptune.
• They are large and gous.

Jupiter

• Jupiter is the fifth planet from the Sun.
• Its average distance from the Sun is 774 million km.
• Jupiter is the solar system's largest planet.
• Its equatorial diameter is 142,984 km.
• Jupiter lacks solid ground, covered in thick clouds.
• It primarily consists of hydrogen and helium.
• Features a massive storm known as the Great Red Spot.
• The average cloud-top temperature is -149°C.
• Jupiter's revolution takes 12 Earth years.
• Its rotation takes 10 Earth hours.
• Jupiter has 50 confirmed moons, with 17 awaiting confirmation.
• Ganymede is the solar system's largest moon.

Saturn

• Saturn is the sixth planet from the Sun.
• Its average distance from the Sun is 1.4 billion km.
• Saturn is the farthest planet visible without a telescope.
• The equatorial diameter is 120,536 km.
• It is a gous giant without a solid surface.
• Its atmosphere is mostly hydrogen and helium.
• Saturn is a cold planet with cloud temperatures of -176°C.
• Rotation: 10.7 Earth hours.
• Revolution: 29 Earth years.
• Saturn has 53 known moons, Titan is the largest.

Uranus

• Uranus is the seventh planet from the Sun.
• Its average distance from the Sun: 2.9 billion km.
• Uranus was the first planet discovered by telescope.
• Its equatorial diameter is 51,118 km.
• It's considered an ice giant composed of frozen water, methane, and ammonia.
• The atmosphere: hydrogen and helium.
• Average surface temperature: -215°C.
• Uranus rotates on its side.
• Rotation: 17 hours.
• Revolution: 84 Earth years.
• Uranus has 11 rings and 27 moons, Titania is the largest.

Neptune

• Neptune is the eighth planet from the Sun.
• Its average distance from the Sun is 4.5 billion km.
• Discovered through mathematical calculations.
• Neptune is similar in size and mass to Uranus.
• Its equatorial diameter is 49,532 km.
• It lacks a solid surface and is a gas giant.
• Surface temperature: -214°C.
• Rotation: 16 Earth hours.
• Revolution: 165 Earth years.
• Neptune has six dark rings composed of fine particles.
• It has 13 moons, Triton is the largest.