The planet Venus has attracted the eyes of people since ancient times. In our firmament, this morning and evening star is clearly visible. It was observed by the ancient Maya. There is a mention of her in their famous calendar. There it is called Noh-Ek, which means "great star". The ancient Egyptians called Venus Tayoumutiri.
For a long time it was believed that these are two different stars. In ancient Greece, they even had two different names. The evening star was called Vesper, and the morning star Phosphorus. The authorship of the definition that this is the same celestial body is attributed to Pythagoras. The name Venus was given to the planet by the Romans, in honor of the goddess of love and beauty.
Phases of Venus
Even before the invention of the telescope, astronomers noticed that Venus periodically changes its luminosity and looks different. However, Galileo described the phases of Venus for the first time in 1610. He observed the planet through a telescope.
In his memoirs, the mathematician Gauss writes that his mother could see the phases of Venus on a clear night without a telescope.
Venus is located closer to the Sun than the Earth, and when moving in orbit from the Earth, we see it differently illuminated by the Sun. The phases of Venus resemble the phases of the moon.
Featuresobservations
The phases of Venus are different from the moon and have their own characteristics. We can never see the full Venus, because at this moment it is behind the Sun. Also, the visual dimensions of the planet in different phases are different. This is due to the difference in distances from the Earth to Venus in different phases. The diameter of the visible sickle is the smaller, the wider the sickle. Venus reaches its greatest brightness in some intermediate phase. This phase corresponds to the beginning of the fourth decade of the cycle. At this moment, it shines 13 times brighter than Sirius (the brightest star in our sky).
The full cycle of phases is 584 days. During this time, Venus overtakes the Earth by one revolution. By observing the phases of Venus every few days for a month, you can understand whether it is approaching us or moving away. The closest distance between Earth and Venus is 42 million km, while the furthest distance is 258 million km.
Determining the phase of Venus
If you observe Venus through a telescope, then there will be no problems with determining its state. But how to determine the phase of Venus if there is no such possibility? You can use the astronomical tables published annually by the International Astronomical Union. The first such tables were discovered during excavations of ancient Babylon in the library of King Ashurbanipal.
With the development of astronautics, scientists got the opportunity to study the phases of Venus from near-Earth orbit, the photo provided additional detail.
Movement of the planet
If you observe the movement of planets in the sky from the Earth, you can see that they are movingacross the sky, now in one direction, then in the other, as if describing loops. The word planet itself comes from the Greek word wanderer (wandering).
This was first described by the ancient Greek astronomer Hipparchus in the second century BC. This reverse motion of the planets is called precession or retrograde phase. This is due to the fact that the Earth, along with other planets, revolves around the Sun, and we observe other planets from the Earth. When the Earth "catches up" with another planet, the planet seems to stop, and then begins to move across the sky in the opposite direction. The retrograde phase of Venus is also well observed from the Earth and plays an important role in astrology. In the retrograde period, astrologers predict a disruption in the normal course of things, the breakup of families, the collapse of hopes.
Venus Exploration
Astronomers and scientists have always tried to get the most information about our space neighbor. Back in 1761, during the passage of Venus through the disk of the Sun, Lomonosov saw an incomprehensible formation and suggested that the planet was surrounded by the same gaseous shell as the Earth. Astronomers, studying Venus through a telescope, saw mountains and oceans. But that was a mistake. Subsequently, it turned out that Venus is covered with a dense layer of clouds and it is impossible to see its surface in the optical range.
During the study of Venus by spacecraft, it was possible to carry out its radar sounding and draw up a real map.
The pressure on the surface of Venus is 95 atmospheres, the temperature on the surface is +480 °C. In the atmosphereVenus is dominated by carbon dioxide, which causes the notorious greenhouse effect and warms the surface.
Once Venus was called the sister of the Earth, but it turned out that this world is completely unsuitable for human existence. But from a scientific point of view, Venus is of great interest and research on this planet continues.
