We will return to the subject of spectroscopy throughout the remainder of this course so this is a particularly important topic to understand. The population of stars in our neighborhood is like the population of people in your neighborhood. They are born at different times so they have different ages. But stars age at different rates, based upon the star's mass, and when they enter old age they go through an amazing transformation to become red giants. In this lesson I'll teach you how a star's physics and structure change as it ages and how red giants come about.
All stars eventually die.
Along the way I will point out some objects that relate to the previous lessons. The auroras are caused by a combination of the Sun 's solar winds and the Earth's magnetic field. In this lesson you will learn about this important area of astrophysics. This will extend your knowledge about the Sun and our own world. Download a copy of StarClock to do computer simulations of stellar evolution and aging.