Look up to the stars at night and you might see a hazy band of light across the night sky. This is our galaxy, called The Milky Way. This spiral galaxy contains about 100 billion stars and is about 80,000 light years in diameter. Billions of galaxies fill the sky. Some are elliptical, some are lenticular, and some are irregular. Collisions between galaxies are common and can trigger star formation. The redshifts of the galaxies show that the Universe is expanding. Applying this same logic to the past leads to the interpretation of a high-temperature, high-density beginning of the Universe called the big bang.
Please answer the following questions:
Examine and describe the concept of a galaxy.
How are the various types of galaxies similar or different?
Explain what a cosmic redshift is and how this provides evidence for the Big Bang Theory of the Universe?
