Milky Way, our galaxy is full of mystery. we believe that the universe consists of several hundred billion galaxies, though their estimation is a difficult task. These galaxies have various shapes, sizes, and ways of their evolution. our galaxy, the Milky Way is one of them. It contains over 100 billion stars. Since we can not go outside the Milky way to see it from there, it is only possible to prepare a schematic drawing of the Milky Way, based on the observation made from the heart in various directions. Today askerweb is going to know this galaxy, as we are inside this galaxy, we can not know or feel the exact shape and size of the Milky Way. According to old men, the sun with its planets and their satellites i.e. the whole solar system is the center of this galaxy, though it was completely wrong, we will know later. Scientists have found 50 such galaxies like Milky Way and Andromeda. They think about after 4 billion years Milky Way and Andromeda collapse and the collision will stay for almost 5 billion years.
FAQs and important facts about the Milky way:
1. Why the name is Milky way?
Anciest Greek word ‘Gala’ means milk. This is the source from where the word ‘Galaxy’ has come. When the ancest Greek saw our galaxy in the sky, milk was the first thing came to his mind. However, that was like a belt or ribon or band of light extending from one end of horizon to other, inclined to some 62.6° with respect to the celestrial equator. According to their Mythology, they thought this way was created by child Herculis, when he
spreaded the drops of milk. so the way of milk became to Milky way. However, this Milky way is called in different names in the different parts of the world, “River of heaven”,”God’s footprint”, “light river” are important among them.
2. Milky Way is a spiral galaxy, but how have we known it?
Galileo was the first person who realized this band having a large collection of stars. This was 1940, wireless Astronomy started. With the help of this new technology, we first were able to take a believable picture of our galaxy. we all know, in the middle there are many particles spread inside this, though a big amount of space is empty. However, hydrogen is the leading particle. in 1944, Van de Hulst from Holand said, there are light Hydrogen atoms spread in the whole galaxy and these atoms spread a special wave of 2.1 c.m. wavelength. His statement was right. Later, the location and speed cloud of Hydrogen was calculated. From this, the picture of the Milky way was clarified and we came to know that we live in a spiral galaxy. If you didn’t know, in the universe there are two types of Galaxies: regular and irregular, elliptical, lenticular, and spiral are among regular shapes. There are also two types of spiral galaxies: normal and barred. However, most galaxies(about 70%) are spiral in the universe.
This is a huge galaxy, to go from one end to another end we need about 1,00,000 light-years. I have mentioned early that ancestors thought the sun is the center of the Milky way, but it was completely wrong. Sun is at a hand(Orion) of this spiral galaxy and at a distance of about 25,000-30,000 light-years. Our galaxy contains two types of stars: population I (newly born stars) at the middle, population II (old stars) at the edges.
Milky way may be divided into three major components:
1. a thin disk of thickness about 2000 light years and containing stars, gas, and dust,
2. a central bulge, and
3. a halo which is roughly spherical and contains roughly 200 globular clusters.
4. Where from the earth can we watch the Milky way more prominently?
As discussed earlier because of the difference between the sidereal day and the mean solar day by 3 min and 56 seconds, stars in the summer Nights observed at a place are different from those in the Winter Nights. On the earth if we stand in the northern hemisphere and in the summer nights, we try to watch the Milky way, we see the galactic center. Whereas in the winter nights, we see opposite the galactic center. So, to an observer in the northern hemisphere summer nights are better than winter nights to keep an eye on the Milky Way. Similarly, for the southern hemisphere, the fact is reversed.
5. What is at the Center of the Milky way?
Galaxy is so big that we cannot know the centre of the Milky Way directly. Between our telescope and the galaxy’s nucleus, there are many many unwanted things that’s why we cannot see the Milky way clearly. Thank God, there is a radio wave. Because radio waves can go through the obstacles which normal light waves can not. With the help of VLA(Very Large Array Radiotelescope), we have found a strong source of radio waves. Some stars and gas clouds are rotating this mysterious source. It seems to be a black hole by observing its properties and we named it Sagittarius A*. Astrophysicists think it is the centre of our Milky way galaxy. They also think every galaxy contains a black hole at its centre.
6. Missing mas of Milky way:
Ancestors thought stars and galaxies are still. But, it’s not right. Everything in this universe is moving. But, as stars are at long distances, their speed can not be felt by us. Our sun takes 22.5 crore years to make a round complete with a constant speed of about 8,00,000 k.m. per hour. Galaxy, as well as Milky way, is not exceptional. they also move with respect to its center. But, unlike the planets move around the sun with Keplar’s laws of motion, the Milky way does not move. The planets at the edge of the solar system move slower than the planets near the center. But for the galaxies including the Milky way the fact is reverse. The reason for such behavior is unknown. The center of mass of the Milky way is not at its center, which can be a powerful reason. But, why is the center of mass of the galaxy not at its center? This reason may be “Missing Mass“. The mass i.e. objects are spread randomly in the whole galaxy, at some points there is no mass. dark matter or antimatter may cause this.
What is missing mass?
from the measured gravitational field, it is possible to calculate the mass of the material required locally to provide the observed gravitational force. On the other side, the mass of the visible stars, gas, and dust can be estimated and is found about one-half of the mass required for the observed gravitational field. This is known as the missing mass problem of the milky way.
This is one of the major unresolved problems in modern astronomy this missing must problem exists in all the galaxies and thus there is a question:
Does there exist in the universe a large amount of non-luminous matter which is undetected (and perhaps is undetectable) except for its gravitational influence?
scientists have an opinion that there is a dark matter in our Milky way whose amount is more than that of the visible matter