TO SATURN
While flying past Saturn, two Voyager probes took amazing pictures. "Voyager, who visited Saturn in 1979-1980, managed to get amazing information that amazed scientists. It turned out that on the outer edge of the rings of Saturn is a great number of narrow rings, as if intertwined with each other. Everything was explained when two more Saturn's companions, Pandora and Prometheus, whose orbits lie on different sides of the rings, were discovered later. The power of their attraction changes the shape of the rings, pushing them together and even twisting one with the other.
Now scientists have sent to the planet a third probe - "Cassini". The probe should reach Saturn in 2004. He, like "Galileo", follows the long way to the goal - past Venus, Earth and Jupiter. The expedition will take him almost 7 years. From Saturn's orbit, the Cassini will send a small Heigens probe to the world's largest satellite, the Titan. When the space probe approaches Titan, its speed will exceed 20,000 km/h, but friction will slow it down, and a few parachutes will provide a soft landing. "Heigens should take atmospheric samples, collect data on the "weather" on the planet, take photographs. The first information will be given to Cassini by Heigens at the time of landing.
OUTER SPACE
GALACTIC RESEARCH
The word "galaxy" comes from the Greek word "galaktikos" - milky. Galaxies are giant star systems scattered across the endless distances of the universe. In the past, astronomers knew little about galaxies. Distant foggy objects attracted increased attention only after the invention of the telescope. Gradually more than 100 such objects were discovered, and already in the XVIII century the first catalogue of nebulae was made (nebulae - cosmic clusters of gas and dust, can be prolonged in several thousand light years. Many nebulae are remnants of exploded stars, or supernovae). Among them are some of the most beautiful creatures of nature, cosmic "wonders of the world" - spiral galaxies, the embodiment of which can serve as a nebula in the constellation of Andromeda, visible, by the way, under favorable conditions with the naked eye - in the form of a small blurred luminous spot. Our Milky Way galaxy also has a spiral shape. Other (non-linear) galaxies, visible without visual aids, but only in the Southern Hemisphere, are the Big and Small Magellanic Clouds. Subsequently, it turned out that these are the nearest "star continents" to us. Elliptic galaxies are quite common. Of extreme research interest are those galaxies that are connected by bridges. There are also small dwarf galaxies. The stars we see in the night sky are the closest to our solar system. And the light band, visible on a dark, clear night, called the Milky Way, is the visible edge of our galaxy - just one of the hundreds of billions of stars that make up the Milky Way. The Milky Way is one of the billions of galaxies scattered across the universe.
It takes hundreds of years for light to reach the nearest galaxies. The farthest of the discovered galaxies today are billions of years away from the Earth. Scientists use a special unit of measurement, the light year, to measure outer space. It represents the distance that a beam of light travels in a year. It is equal to ten million million kilometers, or ten trillion.
THE MILKY WAY
Our galaxy is a 120,000 light-years flat disc with a convex center. The stars on the disk are spiralled (only in the middle of this century did it become clear that the Milky Way is a giant sleeve twisted into a spiral of a huge star system). The number of its stars exceeds 100 billion (the exact number has not been established yet). Where new stars were born or are born, the turns of this huge spiral contain dust and gas. The galaxy's disk rotates in its entirety, like a plate. The angular rotation speed around the center of the individual stars is different. The rotation of the galaxy was discovered by the Dutch astronomer Ian Hendrik Oort (1925). He also determined the position of its center, located in the direction of the constellation of Sagittarius. Our Sun is 30,000 light-years away from the centre of the Milky Way, in the part of the spiral called the Orion branch. Studying the relative motion of the stars, Oort found that the Sun moves around the center of the galaxy in a circular orbit at a speed of 220 km / sec. Modern measurements bring this value up to 250 km/sec.
Our galaxy (like others) is extremely similar to a living organism. It has a kind of metabolism - "space metabolism". Various objects and components of the galaxy's hierarchy are in a state of continuous interaction. Our galaxy, according to most scientists, belongs to relatively young galaxies.