Do You Want To Know More Secrets of Galaxy

"What Is A Galaxy ?"

Image of Galaxy

A galaxy is, by definition, any large collection of stars that can be recognized as a separate physical. In terms of number of stars,dwarf irregular galaxy a little like the Small Magellanic Cloud has about one billion stars in it, but there are even smaller systems that are recognized as galaxies such as Leo I and II dwarf galaxies withabout 1 million stars in them, and Draco system with hundreds of thousands of stars in it. 


The largest star cluster, a globular cluster Messier 15 called about 6 million stars, so we see that for small galaxies, there is a fuzzy set of what we mean by a galaxy and a large cluster. In addition to their mass and number of stars, a galaxy is a collection of stars and gas moving through the universe, regardless of the Milky Way. Globular clusters are swarms of stars round the orbit of the Milky Way, while Leo and Draco Systems seem to be independent collections of stars.


Many galaxies also continue to train new generations of stars. The Milky Way and all spiral galaxies in the shape of it , to produce new stars at a rate of one or two stars per year. These stars are formed in the vast interstellar clouds which accounts for about 1 to 10 percent of the mass of these galaxies. Globular star clusters, on the other hand, are not currently forming stars because the activity that happened billions of years ago and then stopped once all the clouds of gas and dust were used.


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Interesting Facts on Milky Way

"Why Milky Way Special To Us"

Andromeda Galaxy

A misty band of light spread across the night sky is called as Milky Way,the galaxy in which we live.The Sun and its planets,including our earth lie in this quiet part of the galaxy,about half way out from the center of the Milky Way.

The Milky Way is shaped like a huge whirlpool or spiral that rotates once every 200 million years.It is made up of at least 100 billion stars,as well as dust and gas.It is so big that light takes 1,00,000 years to cross from one side to the other!

The center of galaxy is very hard to see because clouds of gas and dust block our view.Scientists think that it contains a super massive black hole that swallows anything passing too close.

The Milky Way was born when countless warm gas clouds came together under the pull of gravity.When the clouds collided,stars were born.Nine billion years after its birth,the Milky Way is settled down.There is a huge black hole at its center,but it is quiet.The Galaxy now consists of billions of stars arranged in a beautiful spiral shape.

The oldest star in the Milky Way is the one named as HE1327-2326.It is located 4000 light years away from the earth.

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Galaxies Do Not Look Alike

"Types Of Galaxies"

Andromeda Galaxy

All Galaxies do not look into alike.In fact,there are three main kinds of galaxies - spiral,elliptical,and irregular.The most beautiful types of galaxies are the spiral galaxies.Their long twisting arms are are-as where stars are being formed.Did you know that we belong to a spiral galaxy ?

The stars found in elliptical galaxies are often very old.This is because elliptical galaxies don't actively create new stars.The stars in the elliptical galaxy are often very close together making the center look like one gaint star.

Irregular galaxies are simply all the galaxies that are not spiral or elliptical.Many irregular galaxies probably used to be spiral,or elliptical until they had some kind of accident,such as crashing into another galaxy,which changed them.Many other irregular galaxies probably were never spiral or elliptical;they simply didn't evolve that way.

The Andromeda galaxy is one of the nearest large galaxies which is about 2.2 million light years away.The other two galaxies are small irregular galaxies called the Magellanic Clouds,and they are relatively near the Milky Way.The Large Magellanic Cloud is at about 160,000 light years,and the small Magellanic Cloud is at about 200,000 light years from us.In 2003,yet another galaxy has been discovered just 42,000 light years from the center of our galaxy.The CanisMajorDwarf,with about one billion stars,is probably our nearest neighbour!

Watch Special Video on Andromeda Galaxy below !

Zodiac

" Different signs of Zodiac "

The word zodiac literally means animals.It refers to the patterns of creatures as seen in the twinkling stars at night.The zodiac belt is the great circle around which our sun apparently moves month by month,throughout the year.

The twelve constellations in the zodiac are Taurus,which is represented by a bull,Aries-the ram,Pisces-the fish,Aquarius-thewatercarrier,Capricorn-the goat,Sagittarius-the archer,Scorpio-the scorpion,Libra- the scales,Virgo-the virgin,Leo-the lion,Cancer-the crab,and Gemini-the twins.

Image of Zodiac

These twelve constellations are called signs of the zodiac,and every month a different sign of the zodiac appeared on the Eastern horizon.Based on the time of year you were born,there will be a specific constellation visible in the night sky,and that constellation is your 'zodiac sign'.


Also Watch special video on different signs of zodiac.

Constellations

" What Are Constellations ? "

Image of Constellation

Constellations are groups of stars visible within a particular area of the night sky.Some were named after animals,mythological characters and scientific instruments.Constellations can be viewed after sunset,and before sunrise.Also,as the Earth turns,you can see different constellations at different times of year.

Some of the most famous constellations are 'Andromeda' and 'Orion' the hunter.

The star groups that make up the constellations came from the imaginations of people like sailors,astronomers,and farmers over many thousands of years.So,why did ancient civilizations look to find patterns among the stars ? The answer is simple.These patterns helped them locate the stars,and their position in the sky.On a clear night,you can see about 1500 stars !

The Great Bear is one of the most prominent constellations in the Northern sky.Actually,it does not look like a bear at all,except for its tail.In North America,it is also called The Big Dipper.If you want to see it,go out at night and face North.Look carefully for a pattern of seven stars.If it is autumn,the stars will look like a saucepan with a bent handle.In spring,it will appear as an upside down saucepan,and at other times,a tilted one.However,it should be a very clear night.Otherwise,you will not be able to see The Great Bear.

" How Many Constellations in the Universe ? "

There are 88 official constellations.This number was established by the International Astronomical Union in 1928.Today,this same organization is in charge of naming celestial bodies.It is the only organization recognized by scientists for this purpose.

" Difference Between Constellation And Galaxy "

Constellations are patterns of stars that we see in the sky,like Leo,Orion,Taurus,and others.A galaxy on the other hand,is a system of stars,dust and gas held together by gravity.There are billions of galaxies in the universe,and the galaxy in which we live is called the Milky Way.

" How Galaxies Developed "

Scientists know that stars form out of gas.They beleive that the Universe itself was once all gas,and that clumps of gas joined together to form young galaxies or protogalaxies.The protogalaxies developed in different ways.Some had huge clumps of gas at the center,which formed massive explosions.many massive explosions forced forced the left over gas out of the galaxy,so that only stars formed from the gas,remained.Protogalaxies that developed in this manner become elliptical galaxies.

Sometimes,a protogalaxy will contain only small clumps of gas.Most of the gas is retained along with the stars that have formed,and the galaxy becomes a spiral galaxy.

Irregular galaxies are probably protogalaxies in which explosions are still happening.sometimes,smaller galaxies move towards each other and merge into bigger galaxies.Our Milky Way galaxy came together in this way.

Watch Special Video on Stars and Constellations

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The Worlds Beyond - Nebula

" What are Nebula "

A nebula is a cloud of gas and dust in outer space.These clouds are often very large,spanning across many light years.They are considered to be the birthplaces of stars.

There are many different kinds of nebula in the sky.A red or pink nebula is called an emission nebula,and it glows,because it is getting rid of the extra energy given to it by near by stars.A blue nebula is called a Reflection nebula.It scatters the blue light from nearby stars,while the rest of the colours are allowed to pass through the cloud undisturbed.Eventually,the blue light escapes the cloud and travels to our eyes.

Another one is called a planetary nebula,but it actually has nothing to do with the planets.Planetary nebulae are formed when a dying sun-sized star begins to shed its outer layers.As the star shrinks,much of its surface layers will be shed,leaving behind a beautiful ring.This ring is only visible for about 50,000 years.

Image of Nebula

" Most Distant Galaxy "

The most distant galaxy from the Earth is about 13 billion light years away.Because of the firestorm of star birth within it,the galaxy is one of the brightest young galaxies in the universe,blazing with the brilliance of more than 10 times that of the Milky Way.The most distant object that you can see with your own eyes is the Andromeda galaxy,which is about 2.2 million light years away from us.

" Magellanic Clouds "

The Magellanic Clouds are one of our nearest neighbours in the Universe.They are three irregularly shaped galaxies that lie some from 150,000 to 200,000 light years from Earth.They are visible from the Southern Hemisphere,and appear to it naked eye as two separate patches of light-the Large and Small Magellanic Clouds.

Also Watch special video on Crab Nebula.