The Inner Planets: Mercury and Venus

 The inner planets of the Solar System are Mercury, Venus, Earth, and Mars. These planets are called terrestrial planets because they have solid, rocky surfaces. Mercury is the smallest and closest to the Sun, while Venus is known for its thick, hot atmosphere. Earth is the only planet known to support life, and Mars is often called the “Red Planet” because of its reddish appearance. The inner planets are smaller and denser than the outer planets and are located closer to the Sun.

Mercury is the closest planet to the Sun and the smallest planet in the solar system. It has a rocky surface covered with craters, similar to Earth’s Moon. Because it is so close to the Sun, temperatures on Mercury can become extremely hot during the day and very cold at night. Mercury has no atmosphere strong enough to trap heat, and it completes one orbit around the Sun in only 88 Earth days.

Venus is the second planet from the Sun and is often called Earth’s “sister planet” because they are similar in size. However, Venus has a very thick atmosphere made mostly of carbon dioxide, which traps heat and makes it the hottest planet in the solar system. Its surface is covered with volcanoes and rocky plains, and the planet rotates very slowly compared to Earth.