Universe | On the clear sky on a beautiful autumn night, we will see, with the naked eye, a few thousand stars. But how many stars are present in the whole Universe? About 9,000 stars can be seen with the naked eye if we take into account observations from both hemispheres of the Earth.
With a binocular, we will see about 200,000, and a small telescope will allow us to count up to 15 million stars, while large observers can see a few billion.
But how many stars are they? How many stars are in the Milky Way?
According to astronomers, the Milky Way is a spiral of medium size galaxies.
Our sun is about 27,000 light-years from the galactic core of Orion’s arm.
Astronomers estimate that our galaxy contains up to 400 billion stars different in size and brightness. Some of these are super-gigantic, like Betelgeuse or Rigel.
Most stars are of medium sizes, such as the Sun.
The vast majority of the stars in the Milky Way galaxy are red dwarf stars.
To go even further with counting stars, we should estimate how many galaxies might exist in the universe.
According to astronomers, there are probably more than 170 billion galaxies in the observable Universe, which lie at a distance of 13.8 billion light-years from us in all directions.
To estimate the total number of stars in the observable universe, you can multiply the number of stars in our galaxy by the number of galaxies in the Universe and you will get around 10 ^ 24 stars. I mean one 1 followed by twenty-four zeros.
Of course, there might be far more stars than this calculation shows.
And as most of them have planets that revolve around them, you can multiply the number of stars by 3 or 4 to estimate the number of planets.
How many places was life possible? How many places has life developed to the level of very advanced civilizations?
Universe | The composition of the stars
Their composition is composed of helium and hydrogen nucleus, and plasma, in which nitrogen, oxygen, neon and carbon can be found, but it must be remembered that the stars can emit both gases and metals, or even more difficult elements in very large amounts small.
The sun is the closest star to Terra. The next nearby star is the Proxima Centauri, which seems to be 250,000 times larger than the Sun.
Proxima Centauri is in the constellation called Alpha Centauri, and its approximate distance from Terra is over 37,000 billion kilometres.
It has been demonstrated that the sun’s light reaches about 8 minutes in time to us, but the other more distant stars make up to millions of years, which means that a man can never in a lifetime see the light of stars close to him.
The colour of the stars
It differs from yellow to orange and bright red, as well as white or even blue, but the hue of a star differs depending on the temperature it has.
Even if the red should suggest the strongest temperature, it looks like the red stars are the coldest and the hottest are the blue ones.
To get an idea of how strong a blue star is, you only have to think about the temperature difference between that of the Sun that is just 6,000 degrees Celsius, since a blue star reaches 30,000 degrees Celsius, so 50 times stronger. Of course, even higher temperatures were recorded.
This power of stars is called by magnitude astronomers, and it has two kinds: the apparent one that can be seen by humans without the help of other objects of astronomical observation and the absolute one, which is of course seen with astronomical objects.a diagram that helped and helped determine the stellar magnitude is the Hertzsprung Russell, representing the graphical interdependence of stellar temperature, also helping to find the age of a star and the evolution it will have.
The brightest star discovered in the last time in our galaxy – the Milky Way, could be the Peony star, also called the nebula, and it was eventually discovered as having a central position in the galaxy.
Peony was discovered with the Spitzer Space Telescope in Nasa and the brilliance is estimated to be 3.2 million times higher than that of the Sun.
But of course star Eta Catarina is much brighter even if it was discovered more than once, it has a power more than 4.7 million times that of the sun.
Of course, after astronomers have finished exploring the entire Milky Way, they will surely be much stronger and shine will be discovered.
Star Peony is estimated to have a very large mass, even 200 times larger than the sun, its mass is considered huge, which will not bring it a very good evolution.
Specialists believe that this star will not be able to sustain weight for a long time and will be scattered, giving birth to several bodies.
Sirius A, of the Alpha Canis Majoris constellation, is, of course, one of the brightest stars, but the universal observable on Earth is 26 times more powerful than the one mentioned above.