Anatomy of the universe

    The universe 

 1- anatomy of the universe speak 

2- galaxies

3- The Milky Way

4-  Nebule and star clusters

5- Stars of northern skies

6-  Stars of southern skies

7- Stars 

8-Small stars

9- Massive stars

10- Neutrons  stars and Black Holes

11- The solar system

12- The sun

13- Mercury 

14-Venus

15-The earth

16-The moon

17- Mars

18 - Jupiter

19-Saturn

20- Uranus

21- Neptune and Pluto

22- Asteroids, comets, and meteoroids

1-Anatomy of the universe

The universe contains everything that exists from the tiniest subatomic particles to galactic superclusters. nobody knows how big the universe is but  astronomers estimate that it contains at least 125 billion galaxies eat comprising an average of 100 billion stars.

 

 the most widely accepted theory about the origin of the universe is The Big Bang theory, which states that the universe came into being in a huge explosion- The Big Bang- that took place between 10 and 20 billion years ago the universe initially consisted of very hot dense fireball of expanding ,cooling gas, after about 1,000,000 years, gas began to condense into localized clmps called protogalaxies. during the next 5 billion years, the protogalaxies continued condensing, forming galaxies in which stars were being born, today billions of years later ,the universe as a whole is still expanding although there are localized areas in which objects are held together by gravity; for example, many galaxies are found in clusters. 

 

The Big Bang theory is supported by the discovery of faint ,cool background radiation coming evenly from all directions. this radiation is believed to be the remnant of the radiation produced by The Big Bang. Small  “ripples’’  in the temperature of the cosmic background radiation are thought to be evidence of slight fluctuation in the density of the early universe, which resulted in the formation of galaxies.

 

 astronomers do not yet know if the universe is “closed’’ which means it will eventually stop expanding and begin to contract, or if it is ‘’open” which means  it will continue expanding forever ...


 

 coming soon

 

 

 

 

 

Comments

Post a Comment

Popular posts from this blog

5-Stars of southern skies

Image
Stars of southern skies When you look at the southern sky, you look towards the galactic center, which has a huge population of stars . As a result, the Milky Way appears brighter in the southern sky than in the northern sky. The southern sky is rich in nebulae and star clusters.It contains the large and small magellanic clouds, which are 2 off the nearest Galaxy to our own.  Stars make fixed patterns in the sky called constellations.However, the constellation are only  apparent grouping of stars, since the distance to the stars in constellation may vary enormously.   The shapes of constellations may change over many thousands of years due to the relative motions of stars.The movement of the constellations across the sky due to the earth motion in space . The daily rotation of the earth causes  the constellations to move across the sky from east to West ,and the orbit of the earth around the sun causes different areas of the sky to be visible in different seasons.The...
Read more

4-Nebulae and star clusters

Image
  Nebulae and star clusters   A nebula is a cloud of dust and gas inside a Galaxy. nebula become visible if the gas glows, Or if the cloud reflects Starlight or obscures light from more distant objects. Emission nebulae shine because their gass emits light when it is stimulated by radiation from hot young stars.       Reflection nebulae because Shine because their best reflects light from stars in or around the nebula. Dark nebulae appear as silhousettes because they block out light from shining nebulae or stars behind them.Two types of nebula are associated with dying stars: planetary nebulae and supernova remnants.   Both consists of expanding shells of gas that  were once the outer layers of a star.A planetary nebula is gas shell drifting away from a dying stella rcore. A supernova remnant is a gas shell moving away from steller core at great speed following a violent explosion called a supernova.     Stars are often found in groups knows ...
Read more

6-Stars of northen skies

Image
  Stars of northen skies W hen you look at the northern sky,you look away from the densely  populated galactic centre, So the northern sky generally appears less bright than the southern sky .    Among the best known sight  in the northern sky are the constellations Ursa Major( the Great Bear) and Orion. Some ancient civilization believed that the stars were fixed to a celestial sphere surrounding the Earth, and modern maps of the sky are based on a similar idea.       The north and South Poles of the imaginary Celestial Sphere are directly above the north and South Pole of the Earth at the points where the Earth’s axis of rotation intersects the sphere.The Celestial North Pole is at the centre of the map shown here, and Polaris( the pole star) lies very close to it     .The celestial equator  marks a projection of the Earth’s equator on the Sphere. The ecliptic marks the path of the sun. across the sky as the earth orbits the sun. ...
Read more