ABOUT OUR UNIVERSE
The combined form of existing matter and energy is called the universe. > In other words, from the smallest molecules to the giant galaxies
1. Universe
The combined form of galaxies is called the universe. The main theories related to the origin of the universe are as follows-
1. Big-Bang Theory: Abe George Lementaver.
2. Equilibrium or Continuous Creation Theory or Steady State Theory: Thomas Gold and Herman Body
3. Pulsating Universe Theory: Dr. Alan Sandeja
4. Inflationary Theory: Allen Guth’s Big Bang theory regarding the origin of the universe.
According to the Big Bang Theory: 1. In the beginning, all the substances from which the universe is made, were located at one place in the form of very small spheres (single atoms), whose incidence was very minute and the temperature and density were infinite.
2. Due to excessive concentration, there was a sudden explosion of the point, which was called Big Bang. This sudden explosion caused scattering of elements, from which ordinary substances were formed. Due to its separation, dark matter was formed, whose aggregation led to the creation of many cosmic bodies. Scientists believe that after the Big Bang.
Galaxy
Galaxy: A group of stars, which appear blurry and which is the gas cluster at the beginning of the star formation process, is called a galaxy. Our Earth has its own galaxy, which is called the Milky Way. 80% of this galaxy known so far is spiral. This galaxy was first seen by Galileo.
A The nearest galaxy (Andromeda) has been named. Devayani to Mandakini
The latest known galaxy is – Dwarf Galaxy
Nebula:
Nebula: It is a cosmic nursery where stars are born. Nebula consists of a cloud of dust and gases. All stars are born in nebulae, except in rare cases in which two neutron stars form a black hole. Anyway, neutron stars and black holes are considered dead stars. The gases found here include hydrogen gas, helium gas and other ionized plasma gases.
*Nebulae are formed due to two different reasons, first is the origin of the universe and second is the supernova formed from an exploding star.
> After the birth of the universe, atoms were born and clouds of dust and gas were formed from these atoms.
>The matter emitted from supernova also gives birth to nebula. Examples of this are Well and Cancer.
>The nebula may also originate from a mixture of the birth of the universe and a supernova.
some types of nebula
1. Emission Nebulae: These are the most beautiful and colourful. It is illuminated by the stars being formed. Example- Eagle and Lake Nebula.
2. Reflection nebulae: These reflect the light of stars. These stars are either inside the nebula or nearby. Example-Pleiades Nebula.
3. Dark nebulae: They block the light coming from behind them like a wall. This is why we can’t see very far into our galaxy.
4. Planetary nebulae: These are formed when a normal star turns into a red giant star and emits its outer layers. For this reason their shape is round. >The Orion Nebula is a group of the coolest and brightest stars in our galaxy. For detailed information about stars see the chapter Physics on Universe