Planets Flashcards
List some things about Mercury.
The closest planet to the Sun is also the smallest. Mercury is a rocky ball covered in meteor craters. It is slightly larger than our Moon and is about one-third the size of Earth. It does not have any significant atmosphere. Mercury experiences extraordinary differences between night and day temperatures on its surface (ranging from 400°C to 183°C). This constant cycle of extreme heating and freezing causes the rock of Mercury to expand and contract, forming immense cracks in the surface.
List some things about Venus.
Venus is often called Earth’s sister planet because of its similar size and composition to Earth. A notable difference, however, is the atmosphere. The atmosphere of Earth provides oxygen and nitrogen. Venus’s atmosphere is almost completely carbon dioxide. Surface features of Venus cannot be seen through optical telescopes because the planet is shrouded in thick clouds. Sulphur mixes with moisture in the atmosphere to rain down as sulphuric acid. In 1990, the Magellan spacecraft began scanning the surface of Venus using a radar probe. It revealed that large portions of the planet are very flat, while other areas have volcanoes, lava flows, and cracks called rifts.
List some things about Earth.
Our little blue planet, third from the Sun, is home to the only life yet discovered in the universe. Besides having a suitable atmosphere and temperature, Earth is the only place known to have water in three phases: liquid, solid, and gas. Water covers nearly three-quarters of Earth’s surface. Earth’s atmosphere is composed mostly of nitrogen and oxygen, components essential to life. Running water, atmospheric effects, and plate tectonics together constantly shape the surface of Earth.
List some things about Mars.
Mars is often called the red planet because the iron in its surface rocks gives it that colour. Despite being half the size of Earth, Mars has about the same amount of surface area. Several extraordinary features mark its surface, such as a volcano that is three times higher than Mount Everest and an 8 km deep canyon that would stretch from Vancouver to Toronto. Mars has a very thin atmosphere of carbon dioxide and can experience winds of more than 900 km/h. Dust storms can cover the whole planet and last for weeks. Mars has two polar ice caps.
List some things about Jupiter.
The largest planet in the solar system is Jupiter. It has a mass 2.5 times greater than that of all the other planets combined. Its “Great Red Spot” has been visible from Earth for more than 300 years. This spot, as large as three Earths, is a storm raging in the clouds of hydrogen and helium that form the planet’s outer layers. Despite its immense size, Jupiter has the shortest day of any of the planets, turning once on its axis every 10 hours. If it were only 100 times more massive, Jupiter might have formed into a small, faint star.
List some things about Saturn.
Saturn, another gas giant, is easily identified by its elaborate system of rings. Its rings are formed from ice particles rather than rocky chunks. Those particles range in size from specks of dust to the size of houses. The rings are 250 000 km wide but can be as thin as 10 m. A sheet of paper the size of a city would have the same thickness to-width ratio as Saturn’s rings. The planet itself is composed mainly of hydrogen and some helium.
List some things about Uranus.
Uranus is the fourth most massive planet in the solar system. A gas giant, it has a similar composition to Jupiter and Saturn, including a ring system composed of ice and dust. The planet gets its distinctive blue colour from the methane gas in its atmosphere (methane absorbs red light). Uranus has an unusual rotation in that it is flipped on its side. As a result, it appears to be rolling through its orbit around the Sun.
List some things about Neptune.
Neptune is the outermost planet and the third most massive. Its composition is similar to that of Uranus, and it has the same dark blue colour. Like the other three gas giants, Neptune has a ring system, but it is very faint. When the Voyager 2 spacecraft flew by Neptune in 1989, it discovered a large, blue, Earth-size patch on Neptune’s surface. The patch, similar to Jupiter’s Great Red Spot, was likely a storm in the clouds of Neptune’s atmosphere. When the planet was viewed again in 1994 through the Hubble Space Telescope, the spot was gone. A new dark spot has since appeared in the northern hemisphere.
