It is the place of our Earth in the Universe that is ours. astronomical address. Why is it needed? It is not necessary to indicate it in the letters, it is not written in the passport - so maybe it would be better without it?
But this can be answered by a person who lived in some thirteenth century AD, who considered the whole world his village. He thought that the sun sets here over those hills, and rises behind such and such little river. A man of the twenty-first century ought to know his astronomical address, because we must differ from our distant ancestors not only in our ability to climb the Internet, but also in our understanding of the picture of the world.
On the other hand, when you study all these abysses of space that take place in astronomy, it becomes really scary, you realize what a grain of sand you are on at the scale of a huge universe. And it begins to seem that it would be better not to know such things, but to live in your own little world and not to think about such distant and incomprehensible substances. Of course, the peculiarities of perception are different for everyone, but personally, I still think that such contemplation of the infinite does not detract from our meaning, but shows us that we are part of something bigger, something immense, which sometimes makes us look at our petty problems -inomu. And if you still decide to find out our true place in the Universe, then you can safely read on. Hope to discover something new.
From Earth to the Solar System
The first point of our astronomical address will be our planet Earth. This is a rather unusual planet, which has a unique composition of the atmosphere, vast oceans on its surface, protected from external radiation by a powerful magnetic field, ozone layer and ionosphere. The earth is at a distance of 1 astronomical unit from the sun.
It is not difficult to guess that the concept itself astronomical unit originated as some reference value. If we translate such a distance into kilometers, we get the distance of the maximum distance of the Earth from the Sun - Aphelion, equal to about 152 million kilometers. So far our planet is located from the Sun. Or is it close?
Apparently, it’s still close, because, for example, Pluto, which is located almost on the border of our Solar System, is already at a distance of 12 billion kilometers, or 80 astronomical units. Such is our great planetary system. And the main place in it is occupied not by the planets, but by our Star - the Sun, which makes up approximately 99% of the mass of the entire Solar system. It is easy to calculate that all the planets, including not only tiny Earth, but also the giant Jupiter, make up less than 1% of its mass.
And it really makes us think about our place in the Universe. In the solar system, the Earth, despite all its features, is just one of the planets of the Earth group, which, besides it, includes Mercury, Venus and Mars.
From the Sun to the Milky Way
But we will move on - we realized that we are among the planets of the Earth Group, in the solar system, which is based on the star Sun. To better understand all scales, it is worth noting that our little Sun, which looks like a small bright lantern from Earth, actually has a diameter equal to almost 109 Earth diameters.
“What a great sun!” - a thought comes to mind. However, by the standards of the galaxy, it is just an ordinary yellow dwarf, a very small and inconspicuous star. Among the bright tribe of stars, there are colossal red giants that are thousands of times larger than the Sun. Here are the scales!
Of course, the Sun also enters into some more large system. And our galaxy is such a system - Milky Way. Its part is visible on a clear moonless night, like a foggy strip passing through the whole sky. If you look at this band through binoculars, then we will see a huge number of stars. And indeed, in our galaxy, in addition to the Sun, there are still about 200 billion stars, although some scientists are of the opinion that they are twice as large. All these stars make up a huge spiral that revolves around its center.
Our Sun occupies a far from central position in this star place, being in one of the branches of the spiral - in the Orion arm. And, like billions of other stars, it revolves around the center of the galaxy. In this case, the Sun is closer to the periphery at a distance of about 26 thousand light years from this center. That is, if you fly there at the speed of light, then thousands of years will pass before we get to the galactic core.
From galaxy to infinity
So we got to the huge Milky Way galaxy, with a diameter of 100 thousand light years, which, in the form of a spiral disk consisting of a myriad of stars, rushes through space and time. But our galaxy is not alone in the universe. There are a huge number of them - modern astronomers can currently observe 100 billion galaxies. But, apparently, they are much more.
Our galaxy has neighbors - the Large and Small Magellanic Cloud and the Andromeda Galaxy. Together with its neighbors, the Milky Way belongs to the local group of galaxies. In addition to these, it includes about 50 other systems.
The local group of galaxies enters, in turn, into a supercluster of Virgo galaxies, which covers galaxies within a radius of 200 million light years and contains about thirty thousand galaxies.
The scale amazes the imagination, enters into a kind of awe before the grandeur of such systems. But what next? Then we can select the part of the Universe that we can observe in all the devices available to us - it is called Metagalaxy. Next comes the entire Universe as a whole, the existence of boundaries for which modern physics, although it recognizes, but their exact definition is still at a hypothetical level.
A chain lined up in front of us, almost going to infinity - our astronomical address:
Earth - Planets of the Earth Group - Solar System - Orion Sleeve - Milky Way Galaxy - Local Galaxy Group - Virgo Supercluster - Metagalaxy - Universe.
I hope now, looking at the starry sky, you will understand how grand the scale of our universe. And how insignificant and at the same time great is the value of a person in it. Someday we will master the solar system, then we will go deep into our galaxy, but even then we will be just grains of sand on the shore of the endless ocean of the Universe. But this only means that we will always strive for something, that there will be no limits to our development, except for those that we set ourselves.
If this article made you distract from the bustle of our earthly life for a while and look into the depths of the universe, even in thoughts, then I did not write it in vain.