Chapters Seventeen and Eighteen

Chapter Seventeen: Chapter 17 begins with Galileo's first look at Saturn. To him, it appeared he was looking at a planet with "handles". But what were they?  Unfortunately, he would never know. These handles were discovered to be a set of rings made of a range of small rocks. These rings are held to their orbits by Saturn's massive gravity. Saturn isn't the only planet to have rings, Jupiter, Uranus, and Neptune also have rings. Each planet's rings are made of different materials. Jupiter's rings consist of tiny, dark particles. Uranus's rings are made of carbon as well as other organic molecules. We aren't exactly sure how rings form around planets, but there are a few ideas floating around. One is that if two planets come close together, one can be ripped to shreds by the other's gravitational pull if it is strong enough. Another idea is that when planets impact with each other, the moons are destroyed and pieces from the collision form rings. By now you probably know about craters and how they are formed. When two bodies crash into each other, the smaller one leaves a huge hole of impact in the other. This is how the moon formed. A huge body crashed into Earth about 4.5 billion years ago. Lots of chunks of Earth entered space and in turn got caught in Earth's gravity. Over a long period of time, they recombined to form the moon we know today.
Chapter Eighteen: Have you ever thought back about the asteroid that collided with Earth long ago? did this ever make you think that one day it could happen again? It is possible. We have been hit by small bodies before, but they have done noting serious to our planet. To really cause devastation to the human civilization, you would need a body at least a few hundred meters across. On estimate, these types of collisions occur to Earth every 200,000 years, so its almost safe to say were are in the clear for a while. Currently, we are working on ways to monitor bodies that could possibly crash into Earth and ultimately, how to prevent these collisions if possible. Two ideas are circling around to prevent a on course collision with an asteroid. One is to use nuclear powered weapons to blow the asteroid to bits, so smaller pieces would burn up in Earth's atmosphere. A different approach also involves nuclear weapons but for a different purpose. If a body were to happen to set a course for Earth, we could possibly explode nuclear weapons near it, hopefully changing its course elsewhere. This really depends on the composition of the asteroid and how it is held together as well as obviously size. If it is held loosely, then smaller large parts, after explosion, would have a larger chance of impacting Earth. This is currently in the works, so hopefully we discover a method soon.