All planets consist mainly of solids. That is one of the differences between a star and a planet. A star is a large glowing ball of gas!
A planet radiates itself no light. Like all planets the earth receives light and warmth of the sun. But a planet reflects sunlight back.
| earth |
Therefore, we can most evenings the moon and planets in the sky are. If you're in a dark room with a flashlight illuminates an object, you see that object. This article does not give light, but only reflects the light of your torch back.
Around the earth is a thick layer of air. This layer of air called the atmosphere or atmosphere. The atmosphere consists mainly of nitrogen and oxygen. The oxygen we need to live.
Our atmosphere is also very important for other reasons. She distributes the heat and the light we receive from the sun. That is why on earth never very hot as on the moon. The axis of the earth is an imaginary line from the south pole of the earth through the center to the Arctic runs. The Earth's axis relative to the sun at a slight angle. This is very important because it creates the seasons.
Perhaps you've learned in school that the sun always rises in the east and sets in the west. That is not entirely correct. Only at the beginning of spring and the beginning of autumn, the sun rises exactly in the east and sets it exactly in the west. At the beginning of the summer, the sun rises in the northeast and consider inter in the northwest. At the beginning of the winter the sun in the southeast at. She then include in the southwest.
The earth rotates on its axis. For once completely rotating the earth 23 hours, 56 minutes and 4 seconds.
Hey, that's weird! A day is still just 24 hours! The difference is because the earth not only rotates around its axis but also around the sun. After 23 hours, 56 minutes and 4 seconds, the stars are in the same position in the sky. That time we call therefore also called a sidereal day. Sometimes you'll need the name sidereal rotation period against.
That means exactly the same.
As said, the stars after 23 hours, 56 minutes and 4 seconds on the same place in the sky. The sun not yet. Because the earth is now also a little further in its orbit around the sun has come we still have three minutes and 56 seconds before the sun is exactly in the same place. The interval of 24 hours is also called a solar day. In exactly one year the Earth turns once around the sun.
The distance between the earth and the sun is not always the same. This is because the orbit of the earth not
beautiful circle. The circle is a bit stretched. Such elongated circle called an ellipse.
In winter, the earth is closest to the sun. The point where the earth is then called the perihelion (peri meaning near, and helios meaning sun). The perihelion is the point in the orbit of a planet where the distance from the sun is the smallest. The opposite point is called the aphelion (apo means far).
The aphelion is the point where the distance to the sun so the greatest is.Dat the earth just in winter closest to the sun may surprise you. Yet it is true. But the seasons occur not because the distance earth - sun is not always the same. Saves so much that either. No, the seasons caused by the tilt of the Earth's axis, do you remember?
If the earth in the perihelion is the distance from the Sun 147,100,000 km (shortest distance). in
the aphelion distance is 152.1 million km (greatest distance).
The average distance Earth - Sun is 149,600,000 km. This distance is called an astronomical unit. This is often abbreviated to A.E. or a.e. In astronomy, a distance of about 150 million kilometers very little. However, a car that ever 100 km / h runs about 170 years to a distance of 150 million kilometers to go. Even the light that has a speed of 300,000 miles per second, doing it for more than eight minutes to get from the earth to the sun to travel.
The diameter of the earth is 12,713 km at the poles. That is the distance between the north pole and the south pole, measured along the axis. At the equator, the larger diameter, ie 12,756 km. The globe is a bit flattened. Almost every planet has a flattening. The earth consists of a core, a mantelen a crust.
| Diameter of the Earth |
The mantle is less hot. About two thousand degrees. The shell is made of different types of rocks. The most outer layer of the earth is called the crust. This is very thin. Among the deepest oceans only five kilometers. In other places, the thickness can be up to forty kilometers.
A large part of the crust caused by volcanism. When a volcano erupts there liquid gesture income from the earth. That is called magma.
The magma is created in the shell. Sometimes it is very hot there.
When the molten rock once flowed from the volcano, it cools down. It is a part of the earth's crust. In places where the crust is very thin often earthquakes.
These are caused by sudden movement of one or more layers of the aardkorst.Bij a landslide, a portion of the earth's crust moved. Such a landslide sometimes occurs in mountainous areas for after heavy rainfall. Even an earthquake can cause a landslide. Below the crust is a firmer layer. Together with the crust is called the lithosphere that layer.
The lithosphere is not continuous layer. It consists of a few very large pieces. Who called the continental plates drift platen.Deze as it were on the stone layer underneath. That sounds pretty crazy, but it is possible. That rock layer below the lithosphere is indeed a bit "malleable". This is due to the high pressure and temperature. That layer called the asthenosphere. It is one of the outer parts of the mantle. By driving the continental plates is it that the world does not lie still on earth. She shifted a bit. That goes very slowly. You notice there is absolutely nothing of!
The earth acts like a big magnet. If you have a compass, you can clearly see that. The needle of your compass points in the direction of the north.
This is due to the magnetic pull of the earth. How's that big earth magnet now arise? That's very hard to explain, but in short, it boils down to this: The earth rotates on its axis. But the inner core of the earth rotates slower than the mantle. The metal in the core now ensures that there is electrical currents to run. These electric currents generate magnetism. The needle of a compass does not point exactly north, but to a point somewhere in northern Canada. This point is called the magnetic north pole.
On the other side of the earth is just a point. That is of course the magnetic south pole. Because the Earth has a magnetic field, there are
radiation belts around the planet. We call that the Van Allen belts.
These are areas where electrically charged particles.
The earth is about the same age as the rest of the solar system. Probably about 4 billion years. Shortly after the creation of the earth, he was very hot.
The inner molten.
The metal core is caused by the heavy metals fell down.
By including the formation of mountains and volcanoes, the current surface is formed. Also, there was one atmosphere.
But it looked very different then than now. As the Earth cooled, it began to rain. And not just a little! For millions of years it has poured. Still, almost three quarters of the surface of seas and oceans. They are then created. You now, very briefly, a theory read about the development of the earth. Though no one knows for sure, most scholars have thought that it must have been about it.
There are also theories about the origin of life on our planet.
One is the theory of evolution.
In the oceans were about 3 billion years ago, small living creatures were formed. Maybe by the action of such lightning.
Because these unicellular beings oxygen separated slowly changed the atmosphere. Half a billion years ago (that's 500 million years ago) developed these creatures to higher animals.
Meanwhile, there were also plants grown. Of the animals died from some species. Nobody knows for sure how that happened. Other animals would have evolved. Only relatively recently published the first cavemen on the scene. Now man is the dominant life form on earth. Many things in the theory of evolution are not entirely clear.
Probably the theory still need to be adjusted.
Earth is the only planet in the solar system where life occurs.
That makes our world a very special planet.
Finally, you will find below a number of numerical data about our planet.
Average distance from the Sun: 1 AU (149,597,870 km)
smallest distance to the sun: 0.9833 AU (147,101,680 km)
greatest distance from the sun: 1.0167 AU (152,098,320 km)
sidereal orbital period: 1.0000388 years
orbital speed: 29.785 km / sec
equatorial diameter: 12756.274 km
polar diameter: 12713.504 km
flattening: 1/298.257.224
Sidereal rotation period: 23h 56m 04.1 s
mass: mass x 1/332.946 Sun
average density: 5.515 g per cubic cm
average temperature: 287 K (14 ° C)
albedo: 30%
absolute magnitude: -3.86
The sidereal orbital period is the time when the planet passes through the entire zodiac and comes back in the same place relative to the same star, as seen from the sun.
The sidereal rotation period of the earth is the time that the earth rotates on its axis relative to the stars.
The absolute magnitude of a planet is the brightness of the planet as they one astronomical unit from the sun while at one astronomical unit from the observer state.
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