In the meantime, about the Earth, perfectly prepared to become our cradle. We were lucky. On earth, several favorable circumstances for life coincided. Not every star becomes a Sun surrounded by planets. Should the nebula rotate more slowly, centrifugal force would not have arisen, fragments would not come off from the central clot, planets would not have arisen. And such a lonely “childless” star would swim in a black abyss, barrenly wasting its heat and light … Not every star that gave birth to planets could create conditions suitable for the birth of life on them. It takes a lot of time, billions of years, for the origin and development of life. All this time the star should burn evenly, calmly, equally. Then the conditions on the planet will be constant – and life will be able to adapt to them. But the stars are far from being not all as calm as our Sun. Young stars sometimes flare up. A wave of incinerating heat hits the surrounding planets, burning, evaporating everything Continue reading
More than anything else – the Universe itself, covering and including all planets, stars, galaxies, clusters, superclusters and cells. The range of modern telescopes reaches several billion light years.
Planets, stars, galaxies amaze us with an amazing variety of their properties, the complexity of the structure. And how is the whole universe, the universe as a whole?
Its main property is uniformity. This can be said more precisely. Imagine that we mentally allocated a very large cubic volume in the Universe, with an edge of 500 million light years. We calculate how many galaxies are in it. Let’s make the same calculations for other, but equally gigantic volumes located in different parts of the universe. If you do all this and compare the results, it turns out that each of them, wherever they are Continue reading
By the beginning of our century, the borders of the explored Universe had moved so far that they included the Galaxy. Many, if not all, then thought that this huge star system was the whole Universe as a whole.
But in the 1920s, new large telescopes were built, and astronomers opened up completely unexpected horizons. It turned out that the world does not end outside the galaxy. Billions of star systems, galaxies, similar to ours and different from it, are scattered here and there in the vastness of the universe.
Photos of galaxies made with the help of the largest telescopes are striking in their beauty and variety of shapes: these are powerful vortexes of star clouds, regular balls, and other star systems do not detect any specific shapes at all, they are ragged and shapeless. All these types of galaxies – spiral, elliptical, irregular – that got their names in appearance in photographs, were discovered by the American astronomer E. Hubble in the 20-30s of our century.
If we could see our Galaxy from afar, then it would appear before us quite different from the one in the schematic Continue reading