Download Solar System Study Guide 1

Solar System Study Guide 1
Vocabulary:
satellite – An object that moves around another object in space; the moon is a satellite of
Earth.
orbit – The path that an object such as a planet makes as it revolves around a second
object.
phase – One of the different shapes the moon seems to have as it orbits around Earth.
revolution – The movement of any object in an orbit, such as Earth moving around the
sun.
axis – An imaginary line which runs through both poles of a planet.
rotation – The motion of a planet or other object as it turns on its axis.
solar system – A group of objects in space that move around a central star.
star – a huge, burning sphere of gases; for example, the sun.
planet – A large object that moves around a star.
asteroid – A small rocky object that moves around the sun.
comet – A small mass of dust and ice that orbits the sun in a long, oval-shaped path.
inner planets – The planets closest to the sun; Mercury, Venus, Earth, and Mars.
outer planets – The planets farthest from the sun; Jupiter, Saturn, Uranus, and Neptune.
Gas giants – Planets which are large spheres made up mostly of gases – for example
Jupiter, Saturn, Uranus, and Neptune.
telescope – A device people use to observe distant objects with their eyes.
space probe – An unscrewed space vehicle that carries cameras, instruments, and other
research tools.
Facts:
My Very Energetic Mother Just Served Us Noodles
Our Solar System – in order from the sun:
Sun – Mercury – Venus – Earth – Mars – Jupiter – Saturn – Uranus – Neptune
The sun is about 150,000 kilometers (93 million miles) from the Earth. It would take you
about 193 years to travel this distance in a car at highway speed!
About 500,000 craters can be seen on the moon through telescopes on Earth. It would
take you more than 400 hours to count them all. And this doesn’t include the craters on
the far side of the moon!
Like most of the planets, Earth has seasons because it is tilted on its axis. But no planet is
tilted like Uranus. Uranus is tilted so far that it is tipped over on its side! This gives
Uranus a winter that lasts about 21 years!
How the Tilts of the Planets Compare:
Planet
Degrees of Tilt
Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune
0
177
23
25
3
25
98
28
Background Information:
Johannes Kepler’s Laws of Planetary Motion – Johannes Kepler, a German
mathematician who lived from 1571 to 1630, recognized that planets travel around the
sun in elliptical rather than circular orbits. His observations resulted in what are now
called Kepler’s three laws of planetary motion:
1. All planets move in elliptical orbits having the sun as one focus (Law of Orbits).
2. A line joining any planet to the sun sweeps out equal areas in equal times (Law of
Areas). This means that the velocity of a planet is different at different places in
its orbit.
3. The square of the orbital period (year) of any planet about the sun is proportional
to the cube of the planet’s mean distance from the sun (Laws of Periods).
Vocabulary/Facts D60-61
Revised 08/05/08 MKH