Hi there! Welcome to the very first Module of this course. We promise this will be fun for you. All we ask is that you think about what we say here, and you will learn a lot from it!

Now, think about this. Because the Sun is so far away from the Earth, it takes Sunlight about 8 minutes and 20 seconds to reach us from the surface of the Sun. But, for this light to reach the Sun's surface from its core, where the light gets generated, may take thousands of years! This is despite the distance from the Sun's core to its surface being much shorter than the distance from its surface to the Earth. Want to know why? Finish this module and we will tell you!