Transcript Star Systems and Galaxies

Galaxies and the
Big Bang Theory
Star Systems and Galaxies
Galaxies
• A Radio Telescope is a device used to detect long
radio waves coming from objects in space.
• A galaxy is a huge group of single stars, star
systems, star clusters,dust, and gas bound together
by gravity
• The three different types of galaxies that exist in
our universe are:
• Spiral Galaxies
• Elliptical Galaxies
• Irregular Galaxies
Spiral Galaxies
• The shape of a spiral galaxy is a bulge in
the middle and arms that spiral outward like
pinwheels
• Many bright, young stars
• Spiral galaxies contain gas and dust
Elliptical Galaxies
• Look like round or flattened balls
• Billions of stars
• Contain very little gas and dust between
stars
• Old stars because little gas or dust and no
stars are forming any longer
Irregular Galaxies
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Galaxy without a regular shape
Smaller than other galaxies
Many bright, young stars
Lots of gas and dust to form new stars
Milky Way
• Our solar system is located in a spiral
galaxy called the Milky Way.
The Expanding Universe
• Big Bang Theory
– Universe formed in an instant
– Billions of years ago
– Enormous explosion
• Universe is expanding
– Leftover thermal energy from the big bang is cosmic
background radiation
Evidence that supports the Big Bang Theory
-Hubble studied the light spectrum of distant galaxies and observed that it
shifted toward the red end of the spectrum
-Hubble compared a galaxies’ spectrum to its distance and found a red shift
(object moving away=longer wavelength (red)