Earth and The Solar System
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Transcript of Earth and The Solar System
EARTH AND THE SOLAR SYSTEMEarth Science
2013Pulford
The Universe
Astronomers define the universe as all of space and everything in it.
Galaxies A galaxy is a huge group of
single stars, star systems, star clusters, dust, and gas bound together by gravity.
There are billions of galaxies in the universe.
The largest galaxies have more than a trillion stars.
Galaxies
Astronomers classify most galaxies into the following types: SpiralEllipticalIrregular
Spiral Galaxy
Elliptical
Irregular
Our GalaxyThe Milky Way
Our solar system is located in a spiral galaxy called the Milky Way.
From the side, the Milky Way would look like a narrow disk with a large bulge in the middle.
But from the top view, the Milky Way would have a spiral, pinwheel shape.
Milky Way-Side View
Sun’s location
Milky Way-Top View
Sun s location
The BIG BANG Accepted theory about how the universe
was created About 13.7 billion years ago, the universe
was no larger than the period at the end of this sentence.
This tiny universe was incredibly hot and dense.
The universe then exploded in what astronomers call the big bang.
Scientific Proof behind the Big Bang Theory
Edwin Hubble was able to study other galaxies and see if the were moving towards us or away from us
He could also tell us how fast they were moving (most galaxies are moving away from us)
Hubble’s law states that the farther away a galaxy is, the faster it is moving away from us. Hubble’s law strongly supports the big bang theory.
Scientific Proof behind the Big Bang Theory
Cosmic Background Radiation In 1965, two American physicists
accidentally detected faint radiation on their telescope.
This mysterious glow was coming from all directions in space.
Scientists later concluded that this glow is the leftover heat energy from the big bang.
This energy was distributed in every direction as the universe expanded.
Animation of the Big Bang
Graphic Organizer
THEORYEvidence