How did we find out about space



Today, modern technology allows us to look into undreamt-of depths in space, and space travel enables us to travel to our closer cosmic surroundings. But many of the fascinating riddles of the universe are still unsolved.

Our earliest ancestors probably already looked up at the sky and marveled at the sun, moon and stars. With the settling down of people and the beginning of agriculture, celestial science became particularly important.

In the advanced civilizations of the Sumerians, the Babylonians and the Egyptians, astronomers recorded when the sun rose and set, how the phases of the moon divided a month, how the sun rose and set at a different point from day to day, evidently at a specific point Annual cycle went through.

On the basis of such observations, the ancient celestial experts created the first calendars - important tools with which people in agricultural societies set the most favorable times for sowing and harvesting.


Early observers noticed that there are special celestial events such as solar or lunar eclipses from time to time and that these recur at fixed intervals. They pictured star constellations in the night sky as constellations and invented myths and stories to explain them and to characterize their meaning.

Chinese astronomers of the Zhou period (11th century to 221 BC) discovered that a year is around 365 days. They also observed comets and supernovae (particularly bright, spectacular star explosions) and discovered that individual stars were moving in the sky. They also considered the nature of these "wandering stars", which were later called planets.

From the 4th century AD, the Maya built temples and pyramids for astronomical purposes. And they created a calendar that was based on the orbital movements of Venus.

Geocentric view of the world

Most of the old world models assumed that the sun, moon, and all stars revolve around the earth. The most important astronomer who drew such a view of the world was Claudius Ptolemy. However, the early astronomers also made discoveries that did not fit into this worldview.

As early as 300 BC, the ancient Greeks knew that the earth had to be a sphere. The astronomer Aristarchus even suspected that the earth orbited the sun, but could not prove it. Hipparchus compiled an extensive catalog of stars and calculated the distance of the moon from the earth.

Copernican turn

An important turning point came with Nicolaus Copernicus (1473 to 1543). As the first star observer in modern history, he declared that the focus of our cosmic environment is not the earth, but the sun. Johannes Kepler formulated the laws governing the movement of planets a little later.

A short time later, Galileo Galilei began systematic observations of the sky with the help of a telescope and discovered, among other things, the four largest of the 67 moons of Jupiter known to date.

With the research of Isaac Newton, the laws of celestial mechanics were further clarified. On the basis of Kepler's laws and Newton's findings, people precisely determined the proportions in the solar system. They also calculated the movements of planets, moons, comets and other celestial bodies exactly and predicted them.

In the 18th and 19th centuries ever larger and better telescopes allowed deeper views into the universe and people gained a lot of new knowledge. Astronomers discovered the planets Uranus and Neptune. They also recognized star clusters and nebulae now, but they did not yet know that they were huge galaxies. At that time, however, astronomers were already dividing the stars into different star types.

The modern

In the 20th century, theoretical physics and astrophysics first advanced research: Albert Einstein revolutionized the worldview with his general and special theory of relativity and brought people one giant step closer to understanding the cosmos.

From the beginning of the space era on, astronomy took on a new quality. Humans moved through space for the first time, visited the Earth's moon and took soil samples. Unmanned probes flew to the planets.

Robots examined the Martian soil, while others analyzed the atmosphere of Venus, measured the solar wind, mapped the surfaces of the moon or explored the magnetic fields of planets. Observation posts outside the earth's atmosphere, such as the Hubble space telescope, allowed views into unimagined depths of the universe.