Science: Galaxies and Beyond
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Transcript of Science: Galaxies and Beyond
GALAXIES AND BEYOND
WHAT ARE GALAXIES?
GalaxiesAre group of star clusters
held together by gravity.Could contain more than 200
billion stars.
MAIN GROUPS OF GALAXIES
1.Spiral Galaxy
Looks like a whirlpool
MAIN GROUPS OF GALAXIES2. Elliptical Galaxy
Shape is similar to a football
Has no spiral arms and little or no dust.
MAIN GROUPS OF GALAXIES3. Irregular Galaxy
Has no recognizable shape
May have been caused by collisions with other galaxies
STARBURST GALAXY
A galaxy that nearly collides with another can undergo a period of intense star formation.
MILKY WAY GALAXY
Our home galaxy
Is a spiral galaxy
To find the center of the galaxy:
1. Look in the center of the constellation Sagittarius, the archer.
What was the Big Bang?
SPECTRUM
• When light passes through water droplets, it separates into a band of colors.• This is because white light is a
combination of all the colors of the rainbow.
• Astronomers think the galaxies must have been closer to each other in the past.• At the beginning moment, the universe
was extremely tiny, hot, and dense.
• From this tiny beginning, the universe expand rapidly.
This expansion called the big bang, sent matter out in all directions.
BIG BANG THEORY• The universe is expanding, and its
temperature are decreasing.• Gravity has caused matter to collect
into clumps, forming stars and galaxies.
BIG BANG THEORY• Background radiation is radiation that
is left over from the beginning moments of the universe.
HOW DID OUR
SOLAR SYSTEM
FORM?
FORMATION OF THE SOLAR SYSTEM• Scientists believe that billions of years
after the big bang, dust and gas in a part of the Milky Way gathered into a nebula massive enough to rotate.
HOW ARE SOLAR SYSTEM FORMED
1. A rotating cloud of gas and dust begin to contract.
2.Protoplanets form, and they orbit a protostar, the Sun.
3.The solar system as it is today emerged.
EARTH• Scientists think that Earth is about 4.6
billion years old. Astronomers think that Earth and its atmosphere developed in a series of stages.
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QUESTIO
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