3-The Milky Way

 

3-The Milky Way

The Milky Way is the name given to the faint band of light that stretches across the night sky. This light comes from stars and nebulae in our Galaxy, known as the Milky Way Galaxy or simply as “The Galaxy’’ is believed to be a barred spiral, with a dence central bar of stars encircled by your arms spiralling outwards and surrounded byless dense halo.

 

 we cannot see the spiral shape because the solar system is in one of the spiral alarms,the orion arm( also called the local arm) from our position the center of the Galaxy is completely obscured by Dust clouds; as a result, optical maps give only a limited view of the Galaxy. however a more complete picture can be obtained by studying radio infrared and other radiation.

 

 the central part of the Galaxy is relatively small and dense and contains mainly older red, and yellow stars. the Halo is a less dense region in which the oldest stars are situated; some of these stars are as old as the Galaxy itself ( possibly 13 billion years). The spiral arms contain main sequence stars and hot young blue stars, as well as nebulae( clouds of dust and 9,460 billion kilometres).in comparison, the solar system seems small, at about 12 light hours 

panoramic view galaxy                  




 

across travel faster thancentre, further out. the sun, which is about two-thirds out from the center, complete one lap of the Galaxy about every 220 million years …

       coning...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