Solar system. Visible movements of celestial bodies: the laws of motion of planets

From the earliest times, mankind was interested in the visible movements of celestial bodies: the Sun, the Moon and the stars. It is difficult to imagine the size of the universe. Our own solar system seems too large, stretching more than 4 trillion miles from the Sun. Meanwhile, the Sun is only one hundredth of a billion from other stars that make up the Milky Way galaxy.

Milky Way

The galaxy itself is a huge wheel that rotates, from gas, dust and more than 200 billion stars. Between them stretch trillions of miles of empty space. The sun was fixed on the outskirts of the galaxy, in shape resembling a spiral: from above the Milky Way looks like a huge rotating hurricane of stars. Compared to the size of the galaxy, the solar system is extremely small. If we imagine that the Milky Way is the size of Europe, then the solar system will not be larger in size than the walnut.

solar system

The sun and its 9 planetary satellites are scattered in one direction from the center of the galaxy. As the planets revolve around their stars, so do stars revolve around galaxies.

The sun will need about 200 million years at a speed of 588,000 miles per hour in order to make a complete revolution around this galactic merry-go-round. Nothing special about our Sun is different from other stars, except that it has a satellite, a planet called Earth, populated with life. Around the Sun, orbits rotate planets and smaller celestial bodies, which are called asteroids.

The first observations of the stars

Man observes the visible movements of celestial bodies and cosmic phenomena for at least 10,000 years. For the first time records in the annals of celestial bodies appeared in ancient Egypt and Sumer. The Egyptians were able to distinguish in the sky three types of bodies: stars, planets and "stars with tails." At the same time, heavenly bodies were discovered: Saturn, Jupiter, Mars, Venus, Mercury and, of course, the Sun and the Moon. The visible movements of celestial bodies are the movement of these objects, contemplated from the Earth, relative to the coordinate system, regardless of the diurnal rotation. The real movement of cosmic bodies is their movement in outer space, determined by the forces acting on these bodies.

Visible galaxies

Looking at the night sky, you can see our nearest neighbor - the Andromeda galaxy - in the form of a spiral. The Milky Way, despite its size, is just one of 100 billion galaxies in space. Without using the telescope, you can see three galaxies and part of ours. Two of them have the names Big and Small Magellanic Cloud. They were first seen in southern waters in 1519 by an expedition of the Portuguese explorer Magellan. These small galaxies make turns around the Milky Way, therefore, are our closest space neighbors.

The third galaxy, visible from the Earth, Andromeda, is distant from us about 2 million light years. This means that the stellar light of Andromeda passes millions of years to get closer to our Earth. Thus, we contemplate this galaxy as it was 2 million years ago.

In addition to these three galaxies at night, you can see a part of the Milky Way, represented by a multitude of stars. According to the ancient Greeks, this group of stars is milk from the breast of the goddess Hera, hence the name.

Visible planets from the Earth

Planets are celestial bodies that revolve around the Sun. When we observe Venus glowing in the sky, it is due to the fact that it is illuminated by the Sun and beats off part of the sunlight. Venus is the Evening Star or the Morning Star. People call it differently, because in the evening and in the morning it is in different places.

As a planet, Venus revolves around the Sun and changes its location. Throughout the day, there is a visible movement of celestial bodies. The system of celestial coordinates not only helps to understand the location of the stars, but also allows you to make star charts, navigate the night sky along the constellations and study the behavior of celestial objects.

The laws of the motion of the planets

Combining observations and theories about the motion of celestial bodies, people brought out the patterns of our galaxy. Discoveries of scientists helped to decipher the visible movements of celestial bodies. The laws of planetary motion, discovered by Johannes Kepler, were among the first astronomical laws.

The German mathematician and astronomer became the pioneer of this topic. Kepler, having studied the works of Copernicus, calculated for orbits the best form, explaining the visible movements of celestial bodies - an ellipse, and brought the laws of planetary motion known in the scientific world as Kepler's laws. Two of them characterize the movement of the planet in orbit. They read:

1. Any planet rotates in an ellipse. In one of its foci there is the Sun.

2. Each of them moves in a plane passing through the middle of the Sun, while in the same periods the radius vector between the Sun and the planet outlines equal areas.

The third law connects the orbital data of the planets within the system.

Lower and upper planets

Studying the visible movements of celestial bodies, physics divides them into two groups: the lower ones, which include Venus, Mercury, and the upper ones - Saturn, Mars, Jupiter, Neptune, Uranus and Pluto. The movement of these celestial bodies in the sphere takes place in different ways. In the process of observable displacement of the lower planets, they have a phase change as in the Moon. When moving the upper planets, you can see that they do not change phases, they are constantly facing people with their bright side.

The earth, along with Mercury, Venus and Mars, belongs to a group of so-called inner planets. They make revolutions around the Sun with internal orbits, unlike large planets that rotate by external orbits. For example, Mercury, which is 20 times smaller than the Earth, revolves around the Sun in its inner orbit.

Comets and meteorites

Around the Sun, other billions of ice blocks spinning, besides planets, consist of frozen solid gas, fine stone and dust, the comets that fill the solar system. Visible movements of celestial bodies, represented by comets, can be seen only when they approach the Sun. Then their tail begins to burn and glows in the sky.

The most famous of them is the Halley comet. Every 76 years, it descends from its orbit and approaches the Sun. At this time, it can be observed from Earth. Even in the night sky you can contemplate meteorites in the form of flying stars - these are clumps of matter that move through the Universe at a tremendous speed. When they fall into the field of gravity of the Earth, they almost always burn out. Because of the extreme speed and friction with the air envelope of the Earth, meteorites are heated and break up into small particles. The process of their combustion can be observed in the night sky in the form of a luminous tape.

The curriculum on astronomy describes the visible movements of celestial bodies. 11 class is already familiar with the laws by which there is a complex motion of the planets, the replacement of the lunar phases and the laws of eclipses.