Uploaded October 2020 | Updated September 2026, 2 hours ago
The two terrestrial planets closest to the Sun are Mercury and Venus. We will be exploring their properties in this video.
Mercury is the smallest and the closest planet to the Sun with a mass of about 3.3 × 10^23 kg or 5.5% of the mass of Earth. It has a solid rocky surface with no atmosphere and surface gravity of 3.7m/s^2 or 0.38gs. Although It lacks an atmosphere, it does have a thin “exosphere” made up of atoms blasted off the surface by the solar wind and striking micrometeoroids. Similar in appearance to Earth’s moon, Mercury’s surface is scarred by many impact craters from comets or meteoroids. The Caloris basin is one of the largest features on Mercury and is about 1,550 kilometers (960 miles) in diameter. Mercury is the second densest planet after Earth, with a large metallic core and an outer shell, (called the mantle), which is about 500 to 600 kilometers (300 to 400 miles) thick. On average Mercury is about 58 million km from the sun and takes approximately 88 Earth days to complete one revolution. It travels at about 180 000 km/h making it the fastest in the solar system. This means that a year on Mercury is equal to only 88 days on Earth. Furthermore, due to its slow spin, a typical day on Mercury lasts about 58 days. This combined with its short year of 88 days, Mercury sees only one sunrise in ever 180 days. Temperatures on Mercury’s surface during the day can reach up to 430 degrees Celsius (800 degrees Fahrenheit) but drop down to –180 degrees Celsius (–290 degrees Fahrenheit) during the night. Despite being the closest to the Sun, Mercury’s surface gets really cold at nighttime since there is no atmosphere to retain the Sun’s heat. If we were to look up at the Sun from Mercury’s surface, it would appear 3 times as large as it does here on Earth. Now that would be an awesome sight!
Venus is the second planet from the Sun at a mean distance of 108 million km with a very thick atmosphere and is the brightest planet in the sky due to its proximity to Earth, and the way sunlight is reflected off its clouds. It has a mass of about 4.9x10^24 kg or about 82% of the mass of the Earth, with a surface gravity of 8.87m/s^2. Venus and Earth are quite similar in size, mass, density, composition, and gravity. However, Venus’s thick atmosphere spins rapidly making the planet reach temperatures higher than 470 degrees Celsius (or 880 degrees Fahrenheit) and causes surface pressure to be 90 times that of Earth. So, if we were to stand on the rocky surface of Venus, it would feel like being 900m (or 3000 ft) below the ocean with temperatures that could melt lead. The atmosphere of Venus consists mainly of carbon dioxide, with clouds of sulfuric acid droplets along with only minute amounts of water. The orbital period of Venus is 225 Earth days while the planet’s rotation period is 243 Earth days, making a Venus day about 117 Earth days long. Since Venus rotates east to west, the sun there would rise in the west and set in the east. Due to its slow rotation, Venus does not have a global magnetic field like the Earth, however, it does have an iron core about 3000 km in a radius that is similar to that of Earth. It is believed that Venus was completely resurfaced by volcanic activity between 300 to 500 million years ago. Volcanic flows have produced long, sinuous channels extending for hundreds of kilometers. Venus has two large highland areas — Ishtar Terra, about the size of Australia, and Aphrodite Terra, about the size of South America. Located at the eastern edge of Ishtar Terra, Maxwell Montes is the highest mountain on Venus and is comparable to Earth’s very own Mount Everest. Although Venus appears similar to Earth and often called Earth’s “sister planet”, it is indeed very different from Earth in many aspects.
The two terrestrial planets closest to the Sun are Mercury and Venus. We will be exploring their properties in this video.
Mercury is the smallest and the closest planet to the Sun with a mass of about 3.3 × 10^23 kg or 5.5% of the mass of Earth. It has a solid rocky surface with no atmosphere and surface gravity of 3.7m/s^2 or 0.38gs. Although It lacks an atmosphere, it does have a thin “exosphere” made up of atoms blasted off the surface by the solar wind and striking micrometeoroids. Similar in appearance to Earth’s moon, Mercury’s surface is scarred by many impact craters from comets or meteoroids. The Caloris basin is one of the largest features on Mercury and is about 1,550 kilometers (960 miles) in diameter. Mercury is the second densest planet after Earth, with a large metallic core and an outer shell, (called the mantle), which is about 500 to 600 kilometers (300 to 400 miles) thick. On average Mercury is about 58 million km from the sun and takes approximately 88 Earth days to complete one revolution. It travels at about 180 000 km/h making it the fastest in the solar system. This means that a year on Mercury is equal to only 88 days on Earth. Furthermore, due to its slow spin, a typical day on Mercury lasts about 58 days. This combined with its short year of 88 days, Mercury sees only one sunrise in ever 180 days. Temperatures on Mercury’s surface during the day can reach up to 430 degrees Celsius (800 degrees Fahrenheit) but drop down to –180 degrees Celsius (–290 degrees Fahrenheit) during the night. Despite being the closest to the Sun, Mercury’s surface gets really cold at nighttime since there is no atmosphere to retain the Sun’s heat. If we were to look up at the Sun from Mercury’s surface, it would appear 3 times as large as it does here on Earth. Now that would be an awesome sight!
Venus is the second planet from the Sun at a mean distance of 108 million km with a very thick atmosphere and is the brightest planet in the sky due to its proximity to Earth, and the way sunlight is reflected off its clouds. It has a mass of about 4.9x10^24 kg or about 82% of the mass of the Earth, with a surface gravity of 8.87m/s^2. Venus and Earth are quite similar in size, mass, density, composition, and gravity. However, Venus’s thick atmosphere spins rapidly making the planet reach temperatures higher than 470 degrees Celsius (or 880 degrees Fahrenheit) and causes surface pressure to be 90 times that of Earth. So, if we were to stand on the rocky surface of Venus, it would feel like being 900m (or 3000 ft) below the ocean with temperatures that could melt lead. The atmosphere of Venus consists mainly of carbon dioxide, with clouds of sulfuric acid droplets along with only minute amounts of water. The orbital period of Venus is 225 Earth days while the planet’s rotation period is 243 Earth days, making a Venus day about 117 Earth days long. Since Venus rotates east to west, the sun there would rise in the west and set in the east. Due to its slow rotation, Venus does not have a global magnetic field like the Earth, however, it does have an iron core about 3000 km in a radius that is similar to that of Earth. It is believed that Venus was completely resurfaced by volcanic activity between 300 to 500 million years ago. Volcanic flows have produced long, sinuous channels extending for hundreds of kilometers. Venus has two large highland areas — Ishtar Terra, about the size of Australia, and Aphrodite Terra, about the size of South America. Located at the eastern edge of Ishtar Terra, Maxwell Montes is the highest mountain on Venus and is comparable to Earth’s very own Mount Everest. Although Venus appears similar to Earth and often called Earth’s “sister planet”, it is indeed very different from Earth in many aspects.
