Scientists use the Earth to study all the other planets. Since no human has ever visited another planet, we have to use what we know about the Earth, and try to guess what the other planets must be like. This is called Comparative Planetology.
The Earth is the planet we all live on! As far as we know, it is the only planet in our solar system that can support life. This is just one of many interesting facts about Earth!
The Earth Orbits and Rotates
The Earth is the third planet from the Sun. Even though it is one of the closer planets, it is still 93 million miles away from the sun. Since it’s so far away, it takes the Earth about 365 days to circle all the way around the sun. That’s why a year is 365 days long!
The Earth is one of the planets that orbits the sun!
The Earth doesn’t just orbit the sun, it also spins like a top! This rotation is the reason why we get night and day. Imagine drawing a line from the North Pole to the South Pole. The Earth rotates around that line, or axis. If you’re having trouble imagining that, think of a globe! A globe spins around its axis the same way the Earth does.
The globe rotates around its axis that goes from the North Pole to the South Pole.
The Earth is on a Tilt!
Another important fact about Earth is that it’s tilted! If we compare the line we drew earlier to Earth’s orbit, our line wouldn’t be exactly up and down. Instead, it would tilt slightly to one side, much like it is on the globe!
This means that parts of Earth are closer to the Sun than others. But the part that is closest changes as the Earth moves around the Sun! The part that is closer during a certain part of the year will be warmer than the part that is farther away. This is why we have seasons! To learn more about Earth’s movement and its tilt, watch the video below.
How Big is the Earth?
The Earth is the biggest of all the terrestrial planets. The terrestrial planets are the dense, rocky planets found in the inner Solar System. But the Earth is much smaller than the gas planets, like Saturn and Jupiter, that are in the outer solar system. If you cut a piece of string long enough to wrap it around the Earth, it’d be 24,901 miles long. That’s longer than 365,000 football fields!
These are the planets, plus Pluto and our moon, in order of size! Can you find the Earth?
Gravity is the force that holds us down to Earth’s surface so we don’t go drifting off into space! It also plays a lot of important roles in the solar system. For example, it holds all the planets in orbit around the sun.
The amount of gravity a planet has depends on its mass. The bigger and denser a planet is, the more gravity it has! Earth’s size means it has enough gravity to hold onto an atmosphere. Smaller planets, like Mars and Mercury, either have a very small atmosphere or none at all!
Earth’s atmosphere is very important for keeping us alive! First, it contains the oxygen we need to breathe. But it also protects us from the dangers of space!
The Earth’s atmosphere is very important for life on Earth!
The atmosphere blocks harmful radiation from the sun from reaching the Earth’s surface. If you get sunburnt from being outside, it’d be much worse without an atmosphere!
The atmosphere also prevents most meteors from reaching the Earth’s surface. Small meteors burn up in the atmosphere before they get anywhere near the surface!
The Magnetized Earth
Another cool fact about Earth is that it has a magnetic field! The magnetic field exists because of movement of material in the Earth’s inner and outer core.The magnetic field protects the Earth from solar wind, which is a stream of material released from the Sun. Without the magnetic field, the solar wind would knock off parts of the atmosphere.
The Earth is the only planet in our solar system that has only one moon!Just like gravity holds the planets in orbit around the sun, the Earth’s moon stays in its orbit because of Earth’s gravity. The moon also has some important effects on the Earth. For example, the moon’s gravity causes the tides in our oceans.
This picture of the moon was taken from the Apollo 8 spacecraft.
Life on Earth
The Earth’s temperature, atmosphere, and many other factors are just right to keep us alive. The Earth is just far enough away from the sun that it is at the right temperature to have liquid water on its surface. In fact, most of Earth’s surface is covered in water, which is very important for living things.