27 Part I – Introduction Galaxy is a group of billions of stars, dust and gas, that are close to one another. The stars we see and the solar system are part of the galaxy. Galaxies are considered as the building blocks of the universe. There are different galaxies that exist in the universe. One of these is the Milky Way galaxy, Milky Way is the galaxy where we belong. It is our home in the universe. Milky Way is a spiral galaxy like pinwheel. Milky Way is a interesting topic because we want to know and learn more about from this. We want to know the characteristics of this, how it is differ from another galaxy what are the things that can be found in this galaxy.
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Transcript
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Part I – Introduction
Galaxy is a group of billions of stars, dust and gas, that are close to one another.
The stars we see and the solar system are part of the galaxy. Galaxies are considered as
the building blocks of the universe. There are different galaxies that exist in the universe.
One of these is the Milky Way galaxy, Milky Way is the galaxy where we belong. It is
our home in the universe. Milky Way is a spiral galaxy like pinwheel. Milky Way is a
interesting topic because we want to know and learn more about from this. We want to
know the characteristics of this, how it is differ from another galaxy what are the things
that can be found in this galaxy.
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A. Background of the Study
The Milky Way is the band of hazy light that looks like a stream of spilled milk in
the night sky, though a telescope this light can be seen to be millions of stars, the Milky
Way is a galaxy, which is a system of stars that more through the universe together. The
sun is one of the stars in the galaxy. There are probably over 100 billion stars in the
Milky Way. There are also dark clouds or Nebulae, which might be dust patches, gas
clouds, or dark bodies. Some areas of the Milky Way have brighter patches and streaks,
which might be nebulae that reflect the light of neighboring stars. Radio telescopes have
picked up noises which may one day explain what these cloudy area really are. Man’s
galaxy is probably similar to other of the spiral galaxies that can be seen through
telescopes. It is believed that from outside the Milky Way, the stars would seem to form a
giant pin wheel with five arms. This pinwheel is constantly spinning around in space.
Some astronomers compare it appearance to a large whirling pancake.
The center of the Milky Way is thicker than the edges, astronomers believe that
the solar system is situated about half – way between the center and the edges of the
Milky way, on the inner edge of the fifth arm, looking toward the center of the Milky
way shows a greater number of stars that can be seen toward the edge of the galaxy. The
Milky Way is believed to be over 100,000 light years wide.
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B. Statement of the Problem
1. What is Milky Way Galaxy?
2. What are the things that can be found in the Milky Way?
3. What are the different shapes and different galaxies?
4. Why do our galaxy called Milky Way Galaxy?
5. How do the universe formed?
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C. Significance of the Study
1. To know more about Milky Way Galaxy
2. To know what are the different kinds of Galaxies
3. To know what are the different shapes of Galaxies
4. To know what are the things can be found in Milky Way Galaxies
5. To know the characteristics of Milky Way Galaxy
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D. Scope and Limitations
This research focused to our galaxy, which is Milky Way. It gives information
that helps us to know more about Milky Way, and gives information that help us to be
aware in the importance of our galaxy in our lives. We will easily know the different
kinds of galaxies and different shapes of galaxies and their characteristics.
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E. Methodology
This term paper gives special task for all of us. Our group spent time, effort, and
money to gain more information through research. This research paper was carefully
finished through the help of each members who gathered information from the school
library, by reading encyclopedia, dictionaries, science book and books that contained
about Milky Way Galaxy.
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F. Definition of Terms
Splashed – to spread or scatter like s splashed liquid (Webster’s English Dictionary)
Nebula – any of many clouds of gas or dust seen in the sky among the stars (Webster’s
English Dictionary)
Diversity – the condition or fact of being different (Webster’s English Dictionary)
Binoculars – a hand held instrument for seeing at a distance that is made up of two
telescopes usually having prisms (Webster’s English Dictionary)
Constellation – any of eighty – eight groups of stars forming patterns (Webster’s English
Dictionary)
Starry – full of stars; consisting of stars; shining like stars (Webster’s English Dictionary)
Universe – all created things including the earth and celestial bodies viewed as making up
one system (Webster’s English Dictionary)
Galaxy – one of billions of collections of stars, gas, and dust that make up the universe
(Webster’s English Dictionary)
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Part II – Main Discussion
From earth, the Milky Way appears like a Milky band of light, it is spiral galaxy
seen from the inside. It is truly vast, more than 100,000 light years in diameter. Viewed
side on, the Milky Way’s disk is seen to be much thinner than its central bulge.
Surroundings it is a halo of globular clusters and old red stars. Young, hot stars shine
within open clusters along the Milky Way’s spiral arms. The galactic bulge is a huge
collection of old redder stars and its center lays a super massive black hole. The Milky
Way contains stars, clusters and gas clouds. All the prominent objects in our night sky
come from a small part of our galaxy. It is one of the grandest sights in the sky is the
Milky Way. In a clear moonless night when you are away from the lights, find the long
cloud of stars that stretches across the sky. This is the Milky Way. The Milky Way is of
special interest to us because the sun is one of the millions of stars that make up the
Milky Way is a band of stars that stretches across the sky. The position of this band of
stars is changes throughout the night and with the seasons. In the open country on a dark
cloudless night the Milky Way is beautiful, dazzling sight. Part of the Milky Way is a
band of stars the stretches. However, you will never have any difficulty in locating this
band on a clear night. Most of the stars that can be seen at light belong to the Milky Way
galactic system. There are about 100 billions stars in the Milky Way. Our sun is one of
these stars.
Our galaxy contains 200 – 400 billions stars, most of which are dimmer than the
sun. On this scale, the solar system is insignificant.
Size of the Milky Way. Its hard to study the Milky Way Galaxy with optical
telescopes because large quantities of interstellar matter block our vision with the aid of
the radio, telescopes, and scientist have determined the structure of the galaxy. The Milky
Way is a large spiral galaxy whose disk is about 100,000 light years wide and about
10,000 light years thick at the nucleus.
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Structure of the Milky Way. Radio telescopes reveal that the Milky Way has
atleast three distinct spiral arms, with some signs of splintering. The sun is positioned in
one of these arms about two thirds of the way from the center, or galactic nucleus, at a
distance of about 30,000 light years. The stars in the arms of the Milky Way rotates
around the galactic nucleus. The most outward arms move the slowest and the ends of the
arms appear to trail. Our solar system orbits the galactic nucleus about every 200 million
years. Surrounding the galactic disk is a nearly round halo made of thin gas and
numerous clusters of stars. These star clusters do not participate in the rotating motion of
the arms but have their own orbits that carry than trough the disk. Although some clusters
are very dense, they pass among the stars of the arms with plenty of room to spare.
Inside the Milky Way. The Milky Way contains stars, clusters, and gas clouds.
All the prominent objects in our night sky come from a small part of our galaxy. The
Milky Way is a band of 100 billion stars that appears as a wide, bright are across the
night sky. These billion stars from a flattened disk with a bulge at the center. 1
A disagreement is developing about the “spiral nebulas” seen as smudges
of light scattered in the night sky. Many astronomers believe that these are clouds of
finely divided material forming part of our galactic system of stars, the Milky Way.
Other’s, such as Heber D. Gurlis of the lick observatory in California, think they are vast
collections of stars or “ island universes ”, many thousand of light years outside the
Milky Way.
____________1 O’Byrne John, Space. . Fog City Press. 2005, p.24
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The U. S. astronomer Harlow Shapley, of the Mount Wilson Observatory in
California, has made the first accurate estimate of the size of the galaxy (also known as
the Milky Way) and where its center lies. Until now, most astronomers have assumed
earth lies near the center of the galaxy, but Shapley reckons the center lies some 50,000
(or 5.8 thousand billion miles – 9.3 thousand billion kilometers) away in the some
direction as the constellation of Sagittarius. Overall, this implies that the galaxy is at least
12,000 light 10 times bigger than previously thought.
A Canadian astronomer, John Plaskett, has discovered a remarkable double star
system (two stars orbiting each other) thousands of light years distant from Earth. Double
stars are common in the Milky Way galaxy, but what distinguishes Placket’s two some in
their sheer size – both stars are larger than any other star ever observed. Plackets found
that each of the luminous, blue – colored stars is about go times larger than the sun.
However, despite their size, the stars are visible to the naked eye because they are so far
away. Even with a good telescope they appear as a single point of light, only by
analyzing their light emissions was Plaskett able to work out that there were two stars
present. 2
We can never see the center of the Galaxy because of the obscuring effect of the
interstellar material. Present knowledge is derived mainly from radio and infrared
astronomy. It lies beyond the star clouds in Sagittarius and is several light years in
diameter. There the highest density of stars is found, and it is estimated that within 2 light
years from the center there are several millions of stars. Very close to the galactic nucleus
astronomers found hot compact clouds moving at the high speed and a very bright and
compact radio source, 0.0001 light – year across. The nature of this object is not yet
understood, although some astronomers believe that it may contain a black hole.
____________2Padilla, Michael J., Miaoulis, lonic, et. al., Prentice Hall Physical Science,
2005 Pearson Education, Inc., p.671
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During World War I, Harlow Shapley (1885 – 1972) in the United States
measured the size of our galaxy. From his studies of RR Lyrae variable stars in globular
clusters and his estimates were very close to nuclear estimates: the disk being about
100,000 light years thick beyond the nucleus, which is much thicker. He also proved that
the sun, together with the Earth and the other members of the Solar System lies well
away from the center; the modern estimate of its distance from the galactic nucleus is
30,000 light years. The comparative size and structure of the Galaxy was uncertain,
however and became clear only with the work of Edwin Hubble (1889 – 1953), who
showed in the 1920’s that the spiral galaxies [3] are external systems, of bathe same basic
type as our own.
If so, then there seemed no reason to doubt that our own Galaxy must also be
spiral (although since the Earth is situated inside it, the spiral effect is naturally lost). The
final proof came from the radio astronomy. During World War II, Hendricks Van de
Hulst (1918) and his colleagues in the Netherlands calculated that the clouds of cold
hydrogen spread through the Galaxy should radiate at a wavelength of 21cm, and in
1951, E. Purcell and H. Ewen, in the United States, showed that this is what does happen,
when the positions and the movements of these hydrogen clouds when where worked out,
an unmistakable spiral structure was found with the sun located between two of the spiral
arms.[5]. It has also been established that the Galaxy is rotating, not as a solid body, at
one rule, but showing differential notation. In the neighborhood of the sun, the revolution
period is of the order of 230 million years – known unofficially as the cosmic years.
The Milky Way as mapped by Martin and Tatiana Kesbula, at the Land
Observatory in Sweden, has coordinates referring to galactic latitude and longitude
measured from the galactic latitude and longitude measured from the galactic plane. The
zero point for the longitude is the intersection between the galactic plane and the celestial
equator near the borders of Aquila and Serpens. The North Galactic pole is in Coma
Berenices, the South Galactic pole is in sculptor.
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The Milky Way, one of the grandest sights in the sky is the Milky Way, on a clear
moonless night when you are away from the lights, find the long cloud of stars that
stretches across the sky. This is the Milky Way. The Milky Way is of special interest to
us, because the sun is one of the millions of stars that make up the Milky Way.
In the open country on a dark, cloudless night, the Milky Way is a beautiful,
dazzling sight. Part of the Milky Way is a band of stars that stretches across the sky, the
position of this band of stars is changes throughout the night and with the seasons.
However, you will never have any difficulty in locating this band on a clear night.
Most of the stars that can be seen at night belong to the Milky Way. These stars
are members of the Milky Way galactic system. There are about 100 billion stars in the
Milky Way. Our sun is one of these stars.
What is the shape of the Milky Way? Where is the sun located in the Milky Way?
(these have been difficult questions to answer. Scientist has said that their problem is
something like that of a prisoner in a jail somewhere in a city who wants to draw a map
of the city. How could he go about making such map? If he could see the city from). If
we could see the Milky Way from a distance, it would be easy to sketch its shape. But,
we are a part of the Milky Way. We are surrounded by the stars that make up the Milky
Way. It is hard to see the shape of something when you are inside it.3The Milky Way is
usually thought of as a standard spiral galaxy. However, recent evidence suggests that the
Milky Way is a barred – spiral galaxy instead. 4
When you see the Milky Way at night during the summer, you are looking toward
the center of the galaxy. The center of the galaxy is about 25,000 light years away, but it
is hidden from view by large clouds of dust and gas. However, astronomers can study the
center using x – rays, infrared radiation and radiowaves..
____________3“The Random House”, Encyclopidia. Ed. 3rd p. 118-1194“Adventures in Science”. Encyclopedia. Ed. 2nd p. 13-17
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On a clear, dark night far from city lights, you can see a faint white band
stretching across the night sky
This is the Milky Way. The Milky Way galaxy has an estimated 200 to 400
billion stars and a diameter of more than 100,000 light years. Every individual star that
you can see with the unaided eye is in our galaxy. The Milky Way’s flattened disk shape
is caused by its rotation. The sun takes about 220 million years to complete one orbit
around the galaxy’s center. At the center of the galaxy is a bulge of stars surrounded by
an immense halo of globular clusters. Recent evidence suggests that there is a massive
black hole at our galaxy’s disk are spiral arms of gas, dust and young stars. Stars are
forming in these spiral arms. 5
The Milky Way is usually thought of as a standard spiral galaxy. However, recent
evidence suggests that the Milky Way is barred spiral galaxy instead. When you see the
Milky Way at night during the summer, you are looking toward the center of our galaxy.
The center of the galaxy is about 25,000 light years away, but it is hidden from view by
large clouds of dust and gas. However astronomers can study the center using x – rays,
infrared radiation and radiowaves.6The Milky Way contains stars, clusters, and gas
clouds. All the prominent objects in our night sky come from a small part of our galaxy.
Astronomers believe that most galaxies must have formed before 10 billion years ago
with in a few billion years of the Big Bang. But they are less sure of how they formed.
Two scenarios have been suggested and its possible that both were at work. Galaxies may
have assembled themselves in stages over a period of billion of years. “Building Blocks”
of material may have come from surrounding globular clusters. The universe was born
almost 14 billion years ago in gigantic explosion that astronomer as second call the Big
bang. For a fraction of a second, it was a super – hot, super – compressed speck of exotic
particles. As it expanded and cooled, familiar particles formed.
____________5”Adventures in Science”. Encyclopedia. Ed. 3rd p. 276 Padilla Michael J., Miaoulis Ionnic, et.al.,Prentice Hall Physical Science. 2005 Pearson Education, Inc; p 425
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Then, atoms formed, later clumping together under gravity’s influence to form
stars, and galaxies. 7
The Milky Way forms a huge, irregular circle of stars titled about 60 degrees to
the celestial equator. Even before the structure of our galaxy was known, the great
astronomers Herchel proposed that this concentration of stars was due to the galaxy
extending farther in space in some directions than in others. It is now clear that in looking
at Milky Way are looking down the long direction of our galaxy. As you look through a
deeper layer of stars, the stars appear more numerous. The Milky Way has both thin and
congested spots. In Sagittarius it is at its brightest, but all of it is a wonder to behold. On a
clear night, the sky is speckled with thousands of stars. In fact, there are just a few of the
200 billion stars belonging to our galaxy, the Milky Way. From the Earth, the thickest
part of the Milky Way looks like a patchy band of white light stretching into space. But
Milky Way is actually shaped like a spiral and is about 100,000 light years across. It has
atleast 2 major arms, made up of dusty nebulae and brilliant blue – white stars. Older
yellow and red stars form the nucleus of the galaxy. As the Earth lies way out on one of
the arms of the imagine what the galaxy looks like from the outside. Clouds of dust and
gas also block much of our view of the middle of the galaxy. Astronomers, however,
have recently determined that a huge object, possibly a black hole lies in the center of the
galaxy. 8
The Great Nebula is the nearest galaxy to the Milky Way. It is a visible galaxy
other than the Milky Way. I t is two million light years away from the Earth. Do you
know why the galaxy called Nebula? Nebula is a Latin word which means cloud. It was
called Nebula because it appears like a band of white clouds. But, it is actually made up
of millions of stars.
____________7 O’ Byrne John, Space. Fog City Pren. P.1418 Irving James Gordon, Stars. Western Publishing Company Inc.,p.44
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The Great Nebula is also called Andromeda Galaxy because it lies in the
constellation of Andromeda. The Andromeda galaxy is located between Cassiopeia and
Pegasus. This galaxy is bigger than the Milky Way. It is similar to the Milky Way in
shape. There are two galaxies in the southern Hemisphere. These are the large
Magellanic. Cloud and the small Magellanic Cloud. These galaxies were at first thought
to be hazy clouds of light only. These two galaxies are also visible to us. Although they
are considered the closest galaxies to the Milky Way, they are 170,000 to 200,000 light
years away from us. Whirlpool Galaxy is about 10 million light years away from us.
Galaxies can be classified according to their shapes. One type of galaxy is called
Elliptical galaxy. This galaxy has a circular and oval shape. It is the most common galaxy
in the universe. It is look like round or flattened balls. It contains billion of stars but has
little and dust between the stars and contain only old stars. Giant Elliptical galaxies are
massive. This galaxy has five trillion stars. Another type of galaxy is the Spiral Galaxy.
This galaxy is similar to a pinwheel. The stars in this galaxy are arranged in the disk. The
arms of a normal spiral galaxy are filled with stars and gas clouds. Some galaxies appear
to have a bulge in the middle and arms that spiral outward like pinwheels. The spiral
arms contain many bright, young stars as well as gas and dust. The third is an irregular
galaxy. It has no definite shape. The Large Magellanic Cloud and the Small Magellanic
Cloud are irregular galaxies. Irregular galaxies have random shapes, and they are smaller
than the Milky Way. Next is a Barred Galaxy, has a bar of stars across its center. The
spiral arms begin at the ends of the bar.
Only about ¼ of all galaxies are spirals and ¼ are irregular. The most numerous
types are elliptical galaxies with shapes ranging from that of a football to globular.
Elliptical vary greatly in size, from around 10 million stars up to the largest galaxies
known, with a hundred trillion members. They contain little gas and few young stars, so
they are predominantly reddish in color. There are no large elliptical galaxies in the local
group, but some small ones are satellite galaxies of Andromeda.
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Spiral galaxies can have tightly coiled arms, emerging from large central disks, or
less tightly coiled ones emerging from smaller disks. The same range of forms appears in
a type of a galaxy described as a barred spiral in which a spiral arms emerges from each
end of a central bulge that takes a bar – shaped rather than a circular form. 9
The Milky Way is our home in the universe. Do you know why it is called the
Milky Way? This because the light of the stars that are mixed with patches of nebulae
appears like drops of milk splashed across the sky. It has band of hazy light that looks
like a stream of spilled milk in the night sky, through a telescope this light can be seen to
be million of stars. A galaxy is an island of matter in space – a giant collection of gas,
dust and millions or billions of stars. The Milky Way Galaxy is in the shape of a disk.
The Earth’s approximately halfway out from the center. Since the Earth is located inside
of the Milky Way, various parts of the galaxy are always visible in our sky. The disk of
the Milky Way is thin. When we look toward away from the center or in any other
directions we see many stars and much gas and dust in those directions we see a band of
white across the sky, mottled with some dark material. People have long called the band
of the light that appears across sky by the home the Milky Way Galaxy because of its
appearance.
Milky Way is just only one of millions of galaxies in the universe. Most galaxies
outside our own are too faint and distant to be seen with naked eye or binoculars, but it is
fascinating to study their shapes in a telescopes. There many other galaxies in the
universe that are similar to the Milky Way Galaxies are sometimes called “island
universe “. A spiral galaxy can be seen in the constellation Andromeda. This is probably
the nearest galaxy to the Milky Way. It is about two million light years away. 10
“Universe” is the word we use to describe everything we know to exist. It is
endless space that contains everything. It includes all the stars, the planets in solar
system, moons, comets, asteroids, gas and dust scattered throughout it.