Assignment 9Chapters 16 &17Thomas Edison State College

Introductory AstronomyAST-101-GS002Semester - October 2013

1.) Outline the solar nebula theory, and explain how the characteristic properties of the solar system provide evidence that supports that theory. The solar nebula theory is the theory in which the planets of the solar system were formed billions of years as the sun condensed from interstellar medium. The planetary system formed from a shaped cloud around the sun. When the sun became luminous enough, dust and gas from the sun exploded, leaving planets to rotate around the sun. The planets formed in rotating disks of gas and dusts around young stars. The first evidence of these disks was bipolar flowing from protostars. There are many characteristic properties of the solar system that provides evidence to support the solar nebula theory. Characteristics such as the stars in our solar system form from disks of gas and dust around them which in turn the planets of the solar system would have formed the same way. Another characteristic is the planets are tiny specks of matter scattered by the sun. The way the solar system looks is another characteristic, since the solar system is basically flat and disk shape and the rotation of the planets is basically that of a disk shape. The solar nebula included elements that composed rock and metals and collisions play an important role in the solar systems history if we look at asteroids we can see a lot. Also by looking at the comets nuclei which are made up of ice one can conclude that solar nebula had icy material.

2.) Compare and contrast the Terrestrial Planets of Earth, Mercury, Venus, and Mars. In what ways are they similar enough to be classified together and how are they different from one another? Terrestrial planets are small dense, rocky worlds. All of the terrestrial planets are made up of rocks and metal and are differentiated which means they are separated into density layers, the high density layer on the inside and the low density layer on the outside. All of the terrestrial planets have similar structure of 3 basic regions: a core of iron, a mantle of rock and a lithosphere or crust.The terrestrial planets may be similar in some ways but are very much different planets that differ in many characteristics. These small worlds tend to be geologically inactive though it is not in the case of all the terrestrial planets. Since Earth has heat flowing through the crust it makes is geologically active but the Earths moon and Mercury cool quickly inside so they have little heat flowing outward which makes it geologically inactive. Mercury is smaller than Earth but larger than Earths moon, Venus is nearly as large as Earth, and Mars about half the size of Earth. Mercury and Earths moon has little to no atmosphere while Venuss atmosphere is thicker than Earths atmosphere, and Mars atmosphere is relatively thin. Venus, Earth, and Mars all have volcanos located on them. Venuss air is about 100times denser than that of Earths so life would not be able to sustain a living there. The main difference between Earth and Venus is the lack of water on Venus and Venus has no evidence of ever having water unlike the planet Mars which does not have water but has evidence of water once being on the planet. ReferencesHorizons: Exploring the Universe, 10th ed., by Michael A. Seeds (Belmont, CA: Brooks/Cole-Thompson Learning, 2008).