Nebula

Nebula

Nebula in Latin is means fog. Nebula is celestial body that almost like lump of cloud that consists of gas and dust, found between the stars.
In universe is many found the spreading of nebula or fog. Fog in universe can be grouped into two kinds:

1. Milky way nebula, it is called like that because that nebula lies in Milky Way galaxy.
2. Outer Galactic Nebula, that is nebulas that exist beyond Milky Way, but that nebula is not equal to gas fog and dust fog that is found in Milky Way. That nebula consists of billions of stars, then it is called the outer galaxy.

Nova and Supernova

Nova and Supernova

Nova means a new star, it is called like that because that star is formerly not observable, then it appears and its light is very bright. The result of research of astronomers shows that Nova and Supernova are not new stars, but they are exploded star so they discharge very bright light.

The first event of Nova was happened on July 4th, 1054, in era Sung dynasty in China. In that era, it is seen a very bright star, so it can be seen in the daylight. Note shows that star lies in constellation of Taurus.

After two years, the star is not seen. Since the creation of modern telescope that is equipped by detectors devices, astronomers see a developing fog in the former place of Nova and Supernova are formed in year 1054. this fog is called crab fog. An American astronomer named Virgima Trimble measured that crab fog developed of velocity 1450 km/sec. he also can predict that all of fog united in their center of about 900 years ago. By using radio telescope is known, that crab fog is strong emitter of radio news.

Milky Way Galaxy

Milky Way Galaxy

Milky Way galaxy is in the beginning assumed to have the shape of giant gas ball that rotates in its axis. Because of its rotation, the shape of Milky Way galaxy is like a disc.
Prof. Kapteyn (1851-1922), a Dutch astronomer argued: Milky Way consists of one big set of stars, that collection has shape like a disc, our sun with its planets, they are fond in one center point of the disc.

Around the center of disc is found the collection of dense stars. The farther from the center, the looser the crowd of stars, but there is no definite outer border.

In 1917, Saphley from Harvard observatory in America, he found that Milky Way galaxy has diameter of about 1,000,000 light years and our sun lies rather to the side of center of galaxy that has distance of about 30,000 light years.

From the result of research, Milky Way galaxy consists of:
1. Star with its planets.
2. Gas fog, for example Nebula Orion, this fog looks shining because of the light of the star its absorbs, which then is emitted again.
3. Dust fog, that is the collection of fog that it can cover some part of Milky Way, such as black part found in the center of Southern Cross constellation. That dark part by sailor is called Coal Sack.

The numbers of stars in Milky Way galaxy is estimated more than 100 billion, while the number of gas fog and dust fog is almost equal to the number of star. Therefore the mass of Milky Way is predicted equal to 200 billion times of Sun’s mass.

According to the prediction of astronomers, in Milky Way galaxy is not only planet Earth that has life. But until now is not found yet its signs.

The characteristics of Milky Way galaxy are as follows:
1. Its shape is like disc.
2. Its middle part is thick and getting thinner to every direction.
3. It is found in our solar system.
4. In the middle part of disc is found about 80 billion stars.
5. In its edge part is found about 20 billion stars.

Galaxy

Galaxy

Galaxy is a group of stars in universe that their amount is large.
If we go out of house in the bright night and doesn’t cloudy also free from the influence of moonlight, then we can see on the sky a light path like giant belt that makes circle. If we observe by using telescope, the light path is union light of billion of stars even more, that lie in one group of certain galaxy. In universe, besides found billion of stars, there are also billions of galaxy, even more. But that we know is only several, including Milky Way galaxy.

Before telescope was found by Galileo-Gelilei (1610), the mistery of galxy is not uncovered yet, so several nations describe galaxy as white light.

For example people of ancient Greek described galaxy as spilled milk in the sky when Juno brestfeed her baby that has name Hercules. It is different with tales of another nation that describes galaxy is the place of dead spirits. Even some describe that galaxy as road for dead spirits to go to their lasting place.

The characteristics of galaxy are as follows.
1. It has its own light.
2. It has core that light in the center, so it is easily recognized.
3. It has certain shapes.
4. the location between one galaxy to another galaxy is very far.

The Shape of Galaxy

Based on its shape galaxy is separated into three:

1. It has shape of Ellipse

The special characteristic of this galaxy is in the middle is found pile of dense stars and have shape like lens ball, middle part is thick, while its edge is thin. The number of galaxy that has shape of ellipse is about 75% of galaxies ever recognize.

2. Spyral shape

The shape of this galaxy is like giant fire whirlpool. Milky Way galxy is included into this shape, while our Sun lies at one middle of that spyra.

3. It has irregular shape

This shape appears like small balls that spread irregularly, without striking edge.

Constellation

Constellation

Constellation is a group of star that its amount is a little and usually given names base on their shapes.
We have already known names such us Scorpio, Librana and so on. Those names often we find in the column of horoscope in magazine or newspaper. That name is actually the name of constellation. The number of constellation that lies near to Earth is 12. besides names of those constellations, there are still another names such as: Ursa Major Constellation (big bear), Gemini constellation (the twin child), Hercules constellation (man of half god). The number of all constellations found by astronomers is 88.

Usually the name of constellation is taken from the name of figure in ancient legend. But every nation imagines the figure formed by that group of star according to their own imagination. For example Scorpio constellation is imagined by people of ancient Greek as Scorpion star.

Basically constellation in universe is found in two places:


1. in south hemisphere of celestial sphere

Consist of Centaurus (involves stars of Alpha Centauri and Betha Cenaturi), Virgo (that involves Spica star), Argo (involves Canopus star), Canis Major (involves Sirius star), and Orion (involves stars of Rigel and Waluku)


2. In north hemisphere of celestial sphere

Consists of constellation of Ursa Major, Aurigia (involves Capella star), Leo (involves Regulus star), Bootes (involves Arcturus star), Libra (involves Wega star), and Siginis (involves Deneb star).

The Method to Measure Temperature of The Star

The Method to Measure Temperature of The Star

How can astronomers measure the temperature of a star?The questions often makes we think, it is remember the distance between star with Earth is very far, especially human ability is limited. Until now, human is not able yet to make plane that it can land on one star of universe’s inhabitant. Although astronomers using big telescope in observing a star, but the star observed is only seen as point of weak light.

Astronomers measure the temperature of the star by using big telescope, because the larger telescope the larger its power of magnification. Star can be photographed by using telescope, the light of the star is gathered by lens in its focus that is completed by film. Eventhough it has been magnified by complete device, often the light received by telescope is still weak, then required longer time for photography. For it can be learned carefully, the light of the star is refracted by prism, the refracted light is called spectrum.

The decomposition of light through the glass prism becomes spectrum is very important in determining temperature of a star, because large or small of star’s temperature can be observed through the decomposition of light color of that star. So the color of the star can be made reference to determine degree of high and low of star’s temperature.

For example, star that has red color is usually its temperature is less hot, on the contrary yellow color means hot and bluish white color is hotter than the colors of red and yellow. So astronomers, in determining the temperature of a star, they do not only use telescope, but they use measuring device and make calculation by using computer.

Base on its volume, the star in universe is divided into three kinds those are giant star, medium star and dwarf star.

Star

Star

Star is celestial body that has its own light and consist of flaming gas. Space between one star to another star, is not empty space, but the collection of gas mixed with dust. That collection of gas and dust does not break because atoms in outer part is attracted to inside. Its attracted of outer part atom to inside is caused by the difference of gravitational force, that gravitational force of atom that is found inside is larger. As the effect of attraction of outer part atom to inside, the collection of gas and dust wrinkles and becomes dense, so temperature inside is high also that densing collection of gas and dust begin to emit light. This is forthcoming of a star called protostar.

Temperature in the center of protostar is higher, when it reaches 10 billion degree Celcius, it happens nucleate reaction where hydrogen is changed to be helium. The longer temperature in protostar increases and causes pressure, so the protostar does not wrinkle anymore, because the pressure inside is able to support the pressure of heavy outer part. If that process has happened, a new star has born.