The planets Flashcards
List the planets in order from the sun and in order in size biggest to smallest?
Mercury, Venus, Earth , Mars, Jupiter, Saturn, Under, Neptune.
Jupiter, Saturn, Uranus, Neptune, Earth, Venus, Mars, Mercury.
What defines a planet?
A planet is a celestial body that
(a) is in orbit around the Sun,
(b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and
(c) has cleared the neighbourhood around its orbit.
Under this definition, Pluto is NOT a planet, but has been deemed a dwarf planet because it has not yet cleared its orbit.
Is Mercury easily seen? How many times does Mercury rotate? Does Mercury have any moons or rings?
Mercury is the closest planet to the Sun and due to its proximity it is not easily seen except during twilight. For every two orbits of the Sun, Mercury completes three rotations about its axis and up until 1965 it was thought that the same side of Mercury constantly faced the Sun.
Mercury does not have any moons or rings.
What would you weight be on Mercury? Does Mercury have a shorter day than Earth? Does Mercury have a shorter year than Earth? Who discovered Mercury? What is it’s diameter?
Your weight on Mercury would be 38% of your weight on Earth.
A day on the surface of Mercury lasts 176 Earth days.
A year on Mercury takes 88 Earth days.
Mercury has a diameter of 4,879 km, making it the smallest planet.
It’s not known who discovered Mercury.
Is Venus easy to see in the sky? How was it named? Is it a similar size to Earth? Why is Venus hot? What are these features made of?
Venus is the second planet from the Sun and is the second brightest object in the night sky after the Moon. Named after the Roman goddess of love and beauty, Venus is the second largest terrestrial planet and is sometimes referred to as the Earth’s sister planet due the their similar size and mass. Venus is nearly as big as the Earth with a diameter of 12,104 km. The surface of the planet is obscured by an opaque layer of clouds made up of sulphuric acid.
Does Venus have any moons or rings? What is Venus made up of? Does Venus have a shorter day than Earth? Does Venus have a shorter year than Earth? What can the surface temperature reach on Venus?
Venus does not have any moons or rings.
Venus is thought to be made up of a central iron core, rocky mantle and silicate crust.
A day on the surface of Venus (solar day) would appear to take 117 Earth days.
A year on Venus takes 225 Earth days.
The surface temperature on Venus can reach 471 °C.
What is unique about the Earth? How long ago was the Earth formed? Our the Earth’s days getting longer or shorter? If so at what speed? Why is Earth’s magnetic field important?
Earth is the third planet from the Sun and is the largest of the terrestrial planets. The Earth is the only planet in our solar system not to be named after a Greek or Roman deity. The Earth was formed approximately 4.54 billion years ago and is the only known planet to support life.
●The Earth’s rotation is gradually slowing. This has the effect of lengthening our days, but it happens so slowly that it could be as much as 140 million years before the length of a day will have increased to 25 hours.
Earth has a powerful magnetic field. This phenomenon is caused by the nickel-iron core of the planet, coupled with its rapid rotation. This field protects the Earth from the effects of solar wind.
How many natural satellites orbit Earth? As a percentage of the body of the planet it orbits how big is this satellite compared to others around other planets? How big is it in real terms compared to other natural satellites? Why were Uranus and Neptune named after Roman gods when they were discovered well after the time of the ancients?
There is only one natural satellite of the planet Earth. As a percentage of the size of the body it orbits, the Moon is the largest satellite of any planet in our solar system. In real terms, however, it is only the fifth largest natural satellite. The Roman method of naming planets was retained for the discovery and naming of Uranus and Neptune.
Who is Mars named after? Why is Mars red? Describe Mars’ atmosphere?
Mars is the fourth planet from the Sun and is the second smallest planet in the solar system. Named after the Roman god of war, Mars is also often described as the “Red Planet” due to its reddish appearance which appears because of a large iron content. Mars is a terrestrial planet with a thin atmosphere composed primarily of carbon dioxide.
Where is the tallest mountain in the solar system? Name it? Describe it? When was it formed? Describe its status?
Mars is home to the tallest mountain in the solar system. Olympus Mons, a shield volcano, is 21km high and 600km in diameter. Despite having formed over billions of years, evidence from volcanic lava flows is so recent many scientists believe it could still be active.
How does the sun appear on Mars? Describe Mars’ seasons? Name two other facts about Mars?
On Mars the Sun appears about half the size as it does on Earth. At the closest point to the Sun, the Martian southern hemisphere leans towards the Sun, causing a short, intensely hot summer, while the northern hemisphere endures a brief, cold winter: at its farthest point from the Sun, the Martian northern hemisphere leans towards the Sun, causing a long, mild summer, while the southern hemisphere endures a lengthy, cold winter.
Pieces of Mars have fallen to Earth.
There are signs of liquid water on Mars.
Define Jupiter’s size? What is Jupiter made of? How bright is it? Is it easy to see? Talk about the length of Jupiter’s day? Describe its years? What does this rotating cause? What are Jupiter’s cloud features made up of? What is the Great Red Spot? How big is it? What is Jupiter’s largest moon?
The planet Jupiter is the fifth planet out from the Sun, and is two and a half times more massive than all the other planets in the solar system combined. It is made primarily of gases and is therefore known as a “gas giant”.
Jupiter is the fourth brightest object in the solar system. Only the Sun, Moon and Venus are brighter. It is one of five planets visible to the naked eye from Earth.
Jupiter has the shortest day of all the planets. It turns on its axis once every 9 hours and 55 minutes. The rapid rotation flattens the planet slightly, giving it an oblate shape.
Jupiter orbits the Sun once every 11.8 Earth years.
Jupiter has unique cloud features. The upper atmosphere of Jupiter is made primarily of ammonia crystals, sulfur, and mixtures of the two compounds.
The Great Red Spot is a huge storm on Jupiter. It has raged for at least 350 years. It is so large that three and a half Earths could fit inside it.
Jupiter’s moon Ganymede is the largest moon in the solar system.
Is Saturn clear in the night sky? What is Saturn known for? What is Saturn made of? How bright is it? Describe its year? What are it’s rings made from? How many moons orbit it? How many spacecraft have visited it?
Saturn is the sixth planet from the Sun and the most distant that can be seen with the naked eye. Saturn is the second largest planet and is best known for its fabulous ring system that was first observed in 1610 by the astronomer Galileo Galilei. Like Jupiter, Saturn is a gas giant and is composed of similar gasses including (primarily) hydrogen, helium and methane.
It is the fifth brightest object in the solar system and is also easily studied through binoculars or a small telescope.
It is named for the Roman god Saturnus.
Saturn orbits the Sun once every 29.4 Earth years.
Saturn has the most extensive rings in the solar system, made mostly of chunks of ice and small amounts of carbonaceous dust.
Saturn has 150 moons and smaller moonlets.
Four spacecraft have visited Saturn.
Is it easy to see? Why was it originally not recognized as a planet? How was it discovered to be a planet? What is unique about Uranus’ angle? Who discovered Uranus? Describe its days and years?
Uranus is the seventh planet from the Sun. While being visible to the naked eye, it was not recognised as a planet due to its dimness and slow orbit. Uranus became the first planet discovered with the use of a telescope. Uranus is tipped over on its side with an axial tilt of 98 degrees. It is often described as “rolling around the Sun on its side.”
Uranus was officially discovered by Sir William Herschel in 1781.
Uranus turns on its axis once every 17 hours, 14 minutes.
Uranus makes one trip around the Sun every 84 Earth years.
Is Uranus cold? Does Uranus have any rings? What are all of Uranus’ moons named after? How many spacecraft have visited Uranus?
Uranus is often referred to as an “ice giant” planet. Uranus hits the coldest temperatures of any planet.
Uranus has two sets of very thin dark coloured rings.
Uranus’ moons are named after characters created by William Shakespeare and Alexander Pope.
Only one spacecraft has flown by Uranus.
