Who invented the earth

22.6.1633

The verdict was reached in the trial against the mathematician and astronomer Galileo Galilei (68). The judges of the Catholic Church agree: Galileo's “Copernican view of the world” contradicts the Bible. Galileo's claim that the earth revolves around the sun has been declared false and not proven.

In the Roman Dominican monastery of Santa Maria, the professor of mathematics had to renounce his teaching while kneeling in front of the guards of the Catholic Church. Instead of imprisonment, Galileo is now threatened with lifelong house arrest. With immediate effect, his books are no longer allowed to be published.

Galileo had observed the starry sky for years for his research. To do this, he used the latest technical tool, the recently invented "telescope". His observations allowed only one conclusion: the earth - like the other planets - revolves around the sun. The Church warned him several times to be careful with such claims. In spite of this, the scientist vehemently advocated this “Copernican worldview”.

The publication of his book “Dialogo” brought the barrel to overflowing: Pope Urban VIII reacted insulted, and so Galileo was brought to justice in Rome. The Church continues to insist on a literal interpretation of Scripture unless there is clear evidence against it.

Copernicus forbidden

Along with the condemnation of Galileo Galilei, the Church also forbade the teaching of the scientist Nicolaus Copernicus. His theory, published almost a hundred years ago, formed the basis of Galileo's scientific work.

The doctor and committed amateur astronomer Nicolaus Kopernikus had published the book "About the revolutions of the heavenly circles" in the year of his death in 1543. In this he contradicted the official opinion of the church. He claimed that the earth was not the center of the world, but a planet that revolved around itself and the sun.

Copernicus must have guessed what this knowledge meant and feared the punishment of the church. Only shortly before his death did he allow his book to be published. Without his knowledge, however, a clergyman added a foreword. The "Copernican view of the world" was presented in it only as a pure hypothesis and calculation aid, not as a proven assertion. Copernicus could not contradict: he did not live to see the first publication of his book.

How does the earth move?

Every morning we see the sun rise, move across the sky and set again in the evening. To us it looks like the sun is moving around the earth. Until the late Middle Ages, many people actually believed that the earth stood still in the middle of the universe and that everything revolved around it.

Today we know that it is exactly the other way round: We experience day and night because the earth is turning. And the earth is neither still nor in the center, but revolves around the sun.

The gravitational pull of the sun holds the earth tight, like on a long leash. More precisely: an almost 150 million kilometers long line. This is the distance at which the earth orbits the sun.

The time it takes the earth to orbit is called a year. During this time, the earth covers a distance of around 940 million kilometers. This means that it races through space at a speed of over 100,000 km / h! (That's nearly thirty kilometers per second.)

By the way, the earth's orbit is not exactly circular, but rather elongated: At the beginning of January, the earth is closest to the sun. Half a year later, at the beginning of July, the gap is greatest. The earth is then a few million kilometers further from the sun than it was in January. But this has nothing to do with the change of the seasons: the difference is so small that the amount of sunlight hardly changes. (And besides, when the earth is closer to the sun in January, it is winter here in the northern hemisphere.)

What is a planet

Perhaps one or the other has noticed a particularly bright star in the morning or evening sky: Venus. After the sun and the moon, it is the brightest object in the sky. Because it shines so brightly, it is also called the “morning star” or “evening star” - much to the annoyance of astronomers: Because Venus is not a star, but a planet!

The most important difference: a star shines by itself, a planet does not. Stars have a source of energy inside them, so they glow hot and emit light. A planet, on the other hand, is cold and does not shine by itself. We can only see it when it is illuminated by a star. Then the surface of the planet distributes the star's light in all directions.

Most planets belong to one star. Because planets do not arise alone, but together with a star. They then belong to this star and orbit it - such as Earth and Venus, which orbit the sun.

And why is Venus so easy to see even though it only transmits the light of the sun? This is due to their thick cloud cover, which reflects sunlight particularly well. In addition, after the moon, Venus is the celestial body that comes closest to earth: just 40 million kilometers - that is a stone's throw compared to the distances in space. Because it comes so close to the earth and its clouds reflect a lot of light, we can easily see it in the sky.

Of course, Venus is not the only planet. Like the earth, it is one of the eight planets in our solar system. And the sun is not the only star with planets either. Since there are an unimaginable number of stars, the universe just has to be teeming with planets.

What is our solar system and how did it come about?

The earth is not alone in space: people have been observing the sun, moon and stars in the sky for a long time. They discovered early on that some stars are moving. These wandering stars were observed and their paths followed. For a long time, however, their movements were not understood - until about five hundred years ago a man by the name of Nicolaus Copernicus solved the riddle: The earth and the "wandering stars" are actually planets, all of which orbit the sun at different distances.

Today we know eight planets. To remember their names in the correct order, the first letters of the sentence "M.a V.ater eclarifies mir jEden S.monday uurens Nachthimmel. “- or in short: M-V-E-M-J-S-U-N.

M.Erkur is the planet that orbits closest to the sun. Then come V.enus, E.rde and M.ars. These four inner planets have a solid surface made of rock and are still relatively close to the sun - only a few hundred million kilometers.

They are circling further out, at a distance of about one to 4.5 billion kilometers from the sun outer planets: Jupiter, S.aturn with his rings, Uranus and all the way outside Neptun. They are made of gas (mostly hydrogen and helium) and are much larger than the inner planets. Jupiter and Saturn are about ten times the size of the earth, that's why they are also called that Gas giants.

And finally there are asteroids, comets, and clouds of dust that also orbit the sun. The gravitational pull of the sun holds all these heavenly bodies together and forces them to fly in a circle like on a long line. Everything together is called that Solar system. The moons are one of them - but they are held in place by the gravitational pull of the planets.

But why does the sun even have planets? This has to do with how the sun came into being: a cloud of gas and dust contracted by its own gravity and became a star. But not all of the material in this cloud was "built into" the star - around one percent was left over. And when the sun began to shine, the radiation pushed the remaining matter back outwards.

The light gases were pushed far outwards, the heavier dust and rocks remained close to the sun. From these clouds of dust and gas, the planets emerged over time. Therefore there are the gas planets outside in the solar system, further inside the rock planets - including our earth - and in the very center the sun. It contains 99% of the mass of the solar system and holds everything together with its gravity.

Why is the earth round?

“What happens if you keep going in the same direction? Will one come to the edge of the world at some point or is the world infinitely large? ”More than 2300 years ago, the famous Greek scientist Aristotle was certain: Neither one nor the other. Because the earth is not flat like a disk, but a sphere - but why?

To understand this, one has to go back to the time when the earth was created. The force that was responsible for this is gravity - all massive objects attract each other. This force made chunks of rock collide and combine to form a planet. And it gave shape to the planet. Because gravity acts equally strong in all directions.

Since the earth was hot and liquid at the beginning, the material was able to flow into the shape dictated by gravity. If a piece of earth protruded somewhere further, it would be attracted by the rest until the surface was smooth and the same force of gravity was acting in all places. And since gravity is the same in all directions, the shape of a sphere was automatically created - because only with a sphere are all points on its surface the same distance from the center of gravity.

However, if you look closely at the shape of the earth, you will see that the earth is not a perfect sphere: it is slightly flattened at its poles and somewhat bulbous at the equator.

The earth's rotation is to blame for this: the earth rotates once around its axis in the course of 24 hours. The rotary movement creates a force, the centrifugal force. We know this from the chain carousel when we fly outwards on the swings. In the case of the earth, the centrifugal force causes the rock masses to slide outwards a little from the axis of rotation, i.e. from the poles towards the equator. There, the diameter of the earth is around 41 kilometers larger than between the north and south poles.