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39 things about the Milky Way

In the Observed Universe there are about 170 billion galaxies. The Milky Way is our galaxy - a very vast and very interesting place, hosting about 100-400 billion stars (with their planets) and over 1,000 nebulae. Not only does it measure between 100,000 and 120,000 light-years in diameter, but it's our home, the birthplace of humanity. Our solar system is 25-28,000 light-years away from the Galactic Center, on the inner edge of one of the spiral-shaped dust and gas particles called the Orion Arm. Surely there are a lot of things unknown yet about our galaxy, but here's what we know so far:

1. The Milky Way has the form of a disc of about 100-120,000 light-years, although it is believed to reach up to 220,000 light-years; the center of the galaxy is bulging and has a diameter of about 12,000 light-years

2. Our galaxy is part of the Local Group - a group of over 50 galaxies; Andromeda is the largest galaxy in the group, followed by the Lactee Way and the Triangle Galaxy; each of them has a galaxy-satellite system; The Local Group is in turn a super-galaxy called Virgo (or Virgo Cluster);

3. From the point of view of size, galaxies are classified as: galaxies, galaxies, medial spiral and elliptical galaxies, the Milky Way being part of the second category; new research suggests that our galaxy is actually about 50% higher than originally thought (~ 150,000 light-years, compared to 100,000, the generally accepted number);

4. Although the Milky Way has an approximate weight of about 400-1000 billion times greater than the Sun, it is not a large galaxy with a diameter of only 100-120,000 light-years away; the largest discovered galaxy is IC 1101 - an elliptical galaxy of 1 billion light-years towards the Milky Way in the Serpent's constellation; IC 1101 has a diameter of 6,000,000 light-years and contains 250 times more stars than our galaxy;

5. Like planets and stars, the galaxies rotate; The Milky Way travels at a speed of 270 km / s and a complete rotation takes about 200 million years; The Solar System performs a complete rotation around the Galactic Center in about 225 million years, that is, a Galactic Year;

6. Andromeda is the nearest Milky Way galaxy, about 2.5 million light-years from the Earth; is the largest galaxy in the Local Group, but not the worst; recent studies suggest that most dark matter is contained in the Milky Way, and is therefore the most massive;

7. The Milky Way and Andromeda attract each other at a speed of 300,000 km / h and the researchers think they will collide in about 4 billion years, forming a super-galaxy elliptical; just as the two galaxies attract, the Local Group is attracted by the Virgo Cluster with 1.6 million km / h, and it is attracted by the Great Magnet - a gravitational anomaly of 250 million light-years - with 22 million km / h;

8. Our galaxy is 10-13.6 billion years old, and the oldest stars are about 13.4 billion years (+/- 800 million years); therefore, according to studies, the Milky Way is not much younger than the Universe itself (13.7 billion years);

9. The Milky Way was formed by colliding with other galaxies over time; currently "conquers" stars from the dwarf galaxies Sagittarius and Caniş Major, as well as matter from Magellan's two clouds;

10. Most galaxies have a supermassive black hole at their center, and the Milky Way is no exception; the center of our galaxy is called Sagittarius A * - a massive source of radio waves, believed to be a black hole measuring 22.5 million kilometers in diameter (roughly as Mercury's orbit); this is just the black hole itself; the whole table trying to enter the black hole is called the acre disk, which has a mass 4.6 million times the sun; the accretion disk would fit within the Earth's orbit; Saggitarius A * has a mass of 4.1 million times the sun compared to an average black hole measuring only 10 solar masses;

11. Scientists believe 90% of the mass of our galaxy is dark matter; this means that the "light" matter - all that we can see with the naked eye or with telescopes - represents only 10% of the Milky Way mass;

12. The galactic disc is curved, which astronomers attribute to the two neighbors of our galaxy - Magellan's Big and Little Clouds; the two dwarf galaxies are part of the Local Group and orbit around our galaxy;

13. The Milky Way contains between 100 and 400 billion stars, although the maximum number of observable stars with the naked eye reaches up to 2,500; this number is not fixed, however, because the galaxy constantly loses stars due to supernovae, but also produces new ones, about 7 per year;

14. Every photo you saw with the Spiral Milky Way is either another galaxy or an artistic interpretation; we can not photograph the galaxy above because we are inside the galactic disc (it would be like trying to take a picture of the house from inside); that does not mean that we can not photograph the beauty of the Milky Way;

15. Until 1920, most astronomers believed that all the stars in the Universe were in the Milky Way; following the Great Debate, the observations made by Edwin Hubble have shown that our galaxy is just one of the billions of galaxies in the Universe;

16. The oldest star of the Milky Way is HD 140283, known as Methuselah; it is about 13.6 billion years old;

17. The Milky Way has a relatively low surface brightness, which means that it is difficult to observe from strongly lighted urban and suburban areas but easy to see when the Moon is under the horizon;

18. If our galaxy was reduced to a diameter of 100 meters, the Solar System would not be more than 1 mm wide;

19. The galactic disc is surrounded by a spherical halo of old stars and globular clusters - of which 90% are 100,000 light-years away from the Galactic Center;

20. In Ancient Egypt it was believed that the Milky Way represents the path to immortality; in their turn, the Chinese call it "Silver River"; In Greek mythology, the Milky Way was formed when Hera poured milk, while feeding Hercules, the son of Zeus; the name "galaxy" also comes from Greek - galaxias, which means milk;

21. In 2002, the star V838 Monocerois erupted, emitting 1 million times more radiation than the Sun; inexplicably, it could have been the collision of two stars or the star devouring a planet;

22. Drake's equation is an argument and an equation conceived by the astrophysicist Frank Drake in 1961; this is used to estimate the number of intelligent extraterrestrial civilizations in our galaxy; recent calculations indicate that there may be between 0 and 15,785 potential alien civilizations in the Milky Way;

23. Sagittarius B2 is a molecular cloud containing 10,000,000,000,000,000,000,000,000,000 liters of alcohol; it is 390 light-years from the Galactic Center and is one of the largest molecular clouds in the galaxy; the cloud is composed of various types of complex molecules, including ethanol, polyvinyl alcohol and methanol; Sagittarius B2 could smell rum and may have raspberry taste due to the ethyl formate concentration;

 24. The most similar planet to Earth is Kepler-186F; this was discovered in 2014 and is 10% higher than our planet; Kepler-18F orbits around its star in the Goldilocks area, meaning there is a big chance that water will be in liquid form here, and alien life as a result;

25. The Greek philosopher Democritus (460-370 BC) is the first person to suggest that our galaxy is made up of stars; Galileo Galilei (1564-1642), however, is the first to observe the galactic disc as well as many stars with his telescope in 1610;

26. The light we can see when looking at the Milky Way is only a form of energy emanating from stars and other heavenly objects; In our galaxy there are other forms of energy such as infrared light, gamma rays, X-rays, radio waves and dark matter;

27. When we look at the sky in the sky, we can see only 0.0000025% of the hundreds of billions of stars in our galaxy;

28. It takes a colossal amount of energy like a star or any other object to leave the galaxy; a star should travel 1.6 million km / h faster than the current speed of 965,000 km / h; astronomers discovered 18 giant blue stars that were ejected outside the galaxy, but they did not find out how this happened;

29. Contrary to the general view, there are no more stars in the arms of the galaxy than the rest; the stars in the Milky Way's arms are massive, shorter in life and high in brightness, making their arms more visible;

30. The space between the planets of the Solar System is relatively dense due to the particles in the solar wind, although the density is much lower than the air, at about 10 million atoms per cubic meter on average; the interstellar space in the Milky Way is much less dense than our solar system, but the strong gravity together holds the gas and the cosmic dust at an average density of about 10,000 atoms per cubic meter; matter in space between galaxies has the lowest density in the Universe, with an average of 1 atom per cubic meter;

31. In the center of the galaxy there are mainly old stars, while younger stars are in their arms;

32. In the center of the Milky Way there is also the highest concentration of stars, as well as the most massive;

33. The closest star to the Solar System is Proxima Centauri, found in the constellation of the Centaur; this is a red dwarf about 4.22 light-years away; it is 8 times smaller than the Sun, but it has an average density of 40 times higher; together with Alpha Centauri A and B, the second and third closest star of the Solar System, form the bright Alpha Centauri;

34. The Orion arm was once considered a "spur", a minor prominence compared to major arms such as Perseus or Sagittarius-Carina; however, new studies suggest that the Orion arm is actually a branch of the Perseus arm and does not originate in the center of the galaxy;

35. The Sun and the Solar System have orbited the galaxy less than 20 times since birth, now 4.6 billion years; since the advent of man we have traveled 1/1250 from orbit;

36. Most of the stars in the Milky Way (and the Universe) are M-type dwarfs - red dwarfs; they represent 75-80% of the total number of stars in the galaxy and have a mass less than half that of the Sun, up to about 0.075 solar masses;

37. According to statistics, for each star in the Milky Way there is at least one planet; with a constant number of 100 billion stars, the result would be between 100 and 200 billion exoplanets existing in our galaxy;

38. More than 2,000 exoplanets are currently found in 1,228 solar systems; exoplanets are hard to find because they do not produce their own light; one of the methods used to discover them is the technique of microgravity lenses, based on the deviation of light from a star behind the gravitational field of another star;

39. If Earth were to orbit the Sun at the same speed as the stars orbit the center of the galaxy, our planet would surround the Sun in just three days instead of 365.
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