Vocabulary: 30.2

Question 1

Earth

Answer 1

The third planet from the Sun is Earth. Unlike other planets in the solar system, Earth’s temperatures allow water to exist in solid, liquid, and gaseous forms on its surface. Water makes life possible here. Earth’s atmosphere is composed primarily of nitrogen and oxygen with traces of carbon dioxide, water vapor, argon, and other gases. Earth has a greenhouse effect and extraterrestrial life

Question 2

Mars

Answer 2

The fourth planet from the Sun is Mars. Mars is also called the red planet because the presence of iron oxide minerals in some of the weathered rocks on its surface gives it a red color. The color of the surface of Mars also varies seasonally due to the common occurrence of severe dust storms. Mars rotates on an axis tilted at an angle of 25 degrees, which is very close to Earth’s tilt. The average temperature on Mars is about 60 degrees Celsius. The polar ice caps of Mars, made up of frozen carbon dioxide and frozen water, grow in winter and shrink in summer.

Question 3

Mercury

Answer 3

Mercury orbits the Sun in 88 days, faster than any other planet in the solar system. Mercury is covered in craters. They discovered a magnetic field around Mercury, suggesting that Mercury has a much larger iron core than expected and is missing some lighter materials in its mantle. One theory to explain the interior of Mercury is that two bodies of similar size collided. They fused together to form a large iron core, and a lighter material vaporized and was lost in space.

Question 4

Venus

Answer 4

An important difference is that the entire surface of Venus is covered by a dense atmosphere. The atmosphere has 92 times the surface pressure of Earth’s atmosphere at sea level. It is composed mainly of carbon dioxide. Clouds in the atmosphere also contain droplets of sulfuric acid and water vapor that help create distinct layers. Clouds on Venus are so dense that only about two percent of sunlight reaches the planet’s surface. This has conducted studies of the surface of Venus absorbed by carbon dioxide from the atmosphere, producing an extreme greenhouse effect. Due to the greenhouse effect, temperatures on the surface of Venus are extreme, between 450 degrees Celsius and 475 degrees Celsius. Venus is the hottest planet in the solar system.