Question

1. What is the study of the cosmos? The study of the cosmos includes what topics?

Answer 1

Answer:

1. Study of cosmos includes the study of the origin and evolution of the universe.

2. Vast majority of astronomers think that the universe was created by the big bang.

3. the greatest evidence is the observation of Edwin Hubble about the receding galaxies. Later on, the Cosmic microwave background radiation was found which was a pretty good evidence.

4. The normal or  baryonic matter, which reflect light, is in the form of great dust clouds, and bunches of galaxies, these galaxies make clusters, and these clusters make giant super clusters. the arrangement of these super clusters is called cosmic web. Baryonic matter is almost 5% and dark matter is almost 27% of the universe. 68% is dark energy.

5. Galaxies are bunch of billions of stars held together by gravitational force. It is important to study galaxies, because it makes our understanding better about our home galaxy Milky way. Furthermore, movement of galaxies tells us about the size and behavior of universe.

Now for second bunch of questions

1. Stars are the basic building blocks of the milky way, which is our home galaxy. The gravitational force of these stars holds them together to maintain the structure of our galaxy milky way.

2. In 1910, Einstein gave general theory of relativity, which changed our perception of time and space. In 1920's theory of expanding universe came into existence. In 1930's we got our introduction to the concept of dark matter. The framework for big bang theory was performed in 1940's. In 1960's we found Cosmic microwave background radiations. In 1970's we came to know about Hawking's radiations. Through out this time, human perception of universe transformed from steady state model of universe to continuously expanding universe.

3. Dark energy is the reason behind accelerated expansion of universe.

4. Matter has its impact on space and time. It is the reason for gravity. This gravity is one of the basic four fundamental forces. Matter creates the galaxies and stars and even all the living things including human beings.

5. Big freeze, Big crunch and big bounce, these are all theories regarding fate of universe. In my opinion, Big freeze is a convincing theory, because due to continuous expansion, the average temperature of universe will fall and will result in everything including stars and galaxies to be frozen.

Answer 2

1. The study of cosmos is known as cosmology. It is a branch of physics and astrophysics, which deals with the study of origin  and evolution of the universe. The cosmology includes the study of nature of the universe. The study of cosmos which is now known as cosmology was earlier known as the celestial mechanics.

2. Most of the astronomers gave different theories regarding the formation of the universe. The most accepted theory is the Big Bang theory. This theory was given by Dr. Stephen Hawkins. According to the Big Bang theory, the universe was formed during a giant explosion occured around 10 to 20 billion years ago. The explosion is known as the Big Bang explosion. Big bang is simply the expansion of the universe during which the energy, time and matter was created. During the expansion of the universe all the matter spread in the space in all the directions and also causes the expansion of space also. After the expansion of the space the universe started cooling due to which the matter, starts combining which are expected to form all the galaxies, stars and planets.

3. The two evidences that supports the Big bang theory are the Red shift and the Cosmic microwave background (CMB) radiation. Due to doppler effect the change in the frequency of the position of lines which represents the spectrum of helium moved towards the red spectum. Hence it is known as the red shift.

The CMB radiation is reffered to the microwaves which are coming from all the directions on the space. These microwaves are the energy waves which are created after the big bang and formation of the universe. All these energy or microwaves are continuously travelling in the space.

4. During the expansion of the universe all the matter spread in the space in all the directions and also causes the expansion of space also. The galaxies are formed and assembled in clusters due to the gravity.  

5. The galaxies are the clusters of stars, it also consists of dust, gas concentrated in the galaxies due to the gravity. The study of galaxies helps to learn about the formation of the universe. These galaxies are visible so that the study of stars, planets become convenient for the astronomers.