Finding their Inner Astronaut: A Child's Guide to the Solar System
The solar system is made up of the Sun and everything that surrounds it. The solar
system is shaped like an egg and the Sun is in the center. There are eight planets,
that we know of, that exist in out system along with their moons and other space
objects, such as asteroids and comets that orbit the Sun. Pluto used to be known
as a planet, but is now considered a dwarf planet. More than 99 percent of the mass
of our solar system is taken up by the Sun.
Mercury is the first of the inner planets, is the closest to the Sun and is the
smallest of all planets in the solar system. It travels faster than any other planet
travels around the Sun and this is because it is closest and smallest. In order
to see this planet from Earth, you have to view it just after the sun sets or just
before the sun rises. This is because it always appears close to the Sun when it
is viewed from Earth.
- The temperature on Mercury can get extremely hot, so much so that it can melt a
- The planet, Mercury, was named after the gods’ swift messenger in the ancient
mythology of Roman.
- The surface of Mercury is full of holes from asteroids and meteorites that have
crashed into it.
- The distance from the Sun to Mercury is 57,900,000 km.
- Two unmanned space probes have visited Mercury.
Venus is another one of the inner planets of the solar system. It looks bright when
looked at from Earth and because of this, it is called the Evening Star. Venus and
Earth are close to the same measurements in size and this planet is the closest
to Earth. The surface of Venus gets extremely hot during the day, so much so that
it can melt a cannonball made out of lead.
- The temperature gets up to 484 degrees Celsius on the side that faces the Sun.
- Thick clouds hold heat and cover the surface of the planet, which is why Venus looks
- Venus rotates opposite from the other planets in the solar system.
- The planet spins very slowly when orbiting the Sun.
- This planet is named after the love and beauty goddess of Greek.
Earth is the third of the four inner planets of the solar system. The atmosphere
consists of many different types of gases, but oxygen and nitrogen are the main
ones. Earth rotates on its axis, which is slightly tilted, no up and down. This
is why there are seasons each year; if the planet rotated straight up and down,
the seasons would be the same all year long.
- Seventy percent of the surface is covered with water.
- Thirty percent is covered by plains, valleys, deserts and volcanoes.
- It takes one year for the planet to orbit around the Sun.
- Earth is the densest and the largest of the inner planets.
- This planet is the only known one that has geological activity (volcanoes and earthquakes).
Mars is the fourth planet in the inner set of planets in the solar system. This
planet is generally a cold planet and is considered cold even on its warmest day.
Some meteorites that have been found on Earth come from pieces of this planet. This
planet has some of the deepest valleys and highest volcanoes in the entire solar
- Mars has two moons with unusual shapes like potatoes.
- Deimos and Phobos are the name of the moons.
- Mars is smaller than Venus and Earth.
- The distance between Mars and the Sun is 228,000,000 km.
Jupiter is the first planet of the outer four planets that exist in the solar system.
It is a large gas planet in which the colors are always changing every day. The
planet s mostly made up of helium and hydrogen gases. Jupiter gives off twice as
much heat as it receives from the Sun.
- Jupiter is so large that all of the solar system’s planets can fit inside.
- There are 63 moons around Jupiter, 50 of which have been named.
- Io is one of the moons and has active volcanoes.
- The Great Red Spot on Jupiter is an area of swirling gas.
Saturn is the second planet of the solar system in the outer four planets. Saturn
looks like a large ball inside of rings when looked at through a telescope. This
planet is also a gas planet and spins very fast on its axis. The planet spins so
fast that the top and bottom of the planet flatten out. The winds in the atmosphere
around Saturn can blow more than 1,800 kilometers in an hour.
- There are more than 1,000 rings surrounding the planet.
- The rings are made of ice and dust.
- Some particles are as small as pebbles, while others are as large as houses.
- The planet has at least 50 moons.
- As meteorites and comets crashed into the moons, the gravitational pull formed them
into parts of the rings.
Uranus is the third of four outer planets in the solar system. It is one of the
smaller planets in the solar system that is made out of gas, but can still hold
64 Earth-size planets. Uranus rotates on its side because the axis is so far tilted.
The planet has a blue-green color that is due to the methane gas.
- Uranus has 27 moons that are named.
- There are 11 rings that are known and are made up of dark particles that are the
size of boulders.
- Some of the moons around the planet are as black as coal and 100 kilometers wide.
- The upper atmosphere of the planet is extremely cold.
- The atmosphere blows 600 kilometers per hour because of the rapid rotation of the
Neptune is the last planet in the outer planets of the solar system. The temperature
on Neptune is extremely cold, so much so that a person needs skin that is thicker
than a polar bear’s in order to stay warm. Winds in this atmosphere blow at
more than 2,000 kilometers per hour. There are dark circles on the surface of this
planet that are thought to be storms.
- Neptune has 13 known moons.
- Four of the 13 known moons orbit the planet within the surrounding rings.
- Triton is one of the moons and travels in an opposite direction that the other moons.
- Neptune has only been visited by one space craft in 1989.
- The distance between Neptune and the Sun is 4,500,000,000 km.