At the beginning of the twentieth century, astronomers thought we were close to the center of the Milky Way because we saw that the density of stars everywhere in the Milky Way was about the same
Globular clusters were later studied and found that most of them were in the direction of Sagittarius. At the same time, he also discovered that it was dust that dimmed the stars near us.
Ken Croswell's The Alchemy of the Heavens is well described.
What this book portrays is accurate. But an unrelated error made our galaxy look bigger than Andromeda and even other galaxies at one point. In fact, Andromeda is larger than the Milky Way, and other galaxies are larger than the former
Stars that are too far away are too dark. We can indeed see globular clusters, as well as a few nearby galaxies. Of course, the vast majority of cases are through telescopes.
Perhaps for a long time, we could not be sure how big our galaxy was, because it was difficult to determine where the boundaries of the galaxy were.
This is very similar to the process of determining the size of the solar system, once we thought that the boundary of the solar system was Saturn, then we found that there was also Uranus, Neptune and Pluto, and then we even found that the solar system actually extended to the outside of the orbit of Pluto - we found the Kuiper Belt, which is full of asteroids and planets similar to Pluto.
As we learn more about the solar system, it seems to be getting bigger and bigger. We learned that beyond the solid objects orbiting the Sun, outside the Kuiper Belt, there is a large piece of space that is affected by the Sun (magnetic fields, etc.). This space called the heliospheric layer contains a large number of charged particles and a huge magnetic field. It's as if the solar system is protected by a giant magnetic bubble that protects us from the effects of outer space.
The word "heliosphere" comes from the Greek word "helios", which means "sun". So within the heliosphere is actually the sun's range of influence.
It's quite possible that the same is true of the Milky Way In other words, beyond the most distant star at the edge of the Milky Way, there is a large area affected by the Milky Way. Similar to the heliosphere, we might call it the galactosphere.
The data sent back by the two Voyager spacecraft deepened our understanding of the heliosphere. But if we want to send a spacecraft to the edge of the Milky Way to see how big the "galactic sphere" is, we may have millions of years to go.
Even more tragically, it will take thousands of years for the signal to reach Earth from this future spacecraft and report the results of the probe.
In other words, for a long, long time, we won't know exactly how big our galaxy really is. By the time we find out, the Milky Way galaxy may have merged with the Andromeda galaxy, and then the merged new galaxy will be larger(/laugh/laugh)."
Now let's forget about the Milky Way! When the Lord manifests his wishes, believers who dedicate themselves to trusting the Lord's generous gifts will have this vast universe as a playground!!!!!
The Milky Way is a galaxy that includes the solar system, and it gets its name from what looks like a river from Earth—a misty band of light in the night sky made up of countless stars indistinguishable to the naked eye. The word Milky Way is a Latin translation of lactera from the Greek γαλαξίας κύκλος (galaxías kýklos, "Milky Way")[19][20][21].
From Earth, the Milky Way is banded because, from the inside, the Milky Way looks like a saucer. Galileo Galilei first used his telescope in 1610 to distinguish individual stars from light bands. But until the early 1920s, most astronomers believed that the Milky Way included all the stars in the universe. Observations by Edwin Hubble, after the 1920 Great Debate of the Century between astronomers Harlow Shapley and Heber Curtis,[23] suggested that the Milky Way was just one of many galaxies.
The Milky Way is a barred spiral galaxy with a visible diameter between 150,000 and 200,000 light-years (ly). [24] [25] [26] [27] It is estimated to contain between 100 and 400 billion stars,[28][29] and planets of at least this magnitude. The halo of dark matter surrounding the Milky Way is up to 2 million light-years wide. [5] The Solar System is approximately 27,000 light-years from the center of the Milky Way,[15] at the inner edge of the Orion Arm, one of the spiraling gathering areas of gas and dust. Those stars within 10,000 light-years of the Galactic Center form a nuclear ball from which one or more bands radiate. At the center of the Milky Way is a powerful power source known as Sagittarius a*, a supermassive black hole with a 4.100 (± 0.034) solar mass.
Stars and nebulae that are farther away from the center of the Milky Way are rotating around the center at a speed of about 220 kilometers per second. Such a constant rotational velocity violates Kepler's laws of motion, suggesting that the vast majority of the Milky Way's mass (about 90%)[32][33] comes from things that telescopes "can't see"—things that neither emit nor absorb electromagnetic waves. These hypothetical things are called "dark matter." [34] Measured by the radius of the Sun, the rotation period of the celestial body is about 240 million years. At the same time, the entire Milky Way is moving at a speed of about 600 kilometers per second relative to the extragalactic reference system. The oldest star in the Milky Way lives about the same life as the universe, around the beginning of the flood after the Big Bang.
The Milky Way has several satellite galaxies that are part of a group of local galaxies. The local galaxy group belongs to the Virgo supercluster, which itself is a component of the laniakea supercluster. [36] [37]
by: quora
fy: Fan Rui sauce
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