Chapter two and three

Chapter and three deal with cosmos. Chapter two focuses on our solar system, whereas chapter three includes the whole cosmos. The solar system is a huge family with lots of members, some of which are the sun, nine planets, moons, asteroids, and comets. Every member has its obit and never runs into others’. This is because there exists the gravitational force between these members. The law of motion keeps all the members in their tracks. The sun is the head of the solar system. It is really gigantic. If I don’t remember wrongly, the sun can contain 130 earths in its stupendous volume. The sun has many spheres. Each sphere has its own character. The planet nearest to the sun is mercury whose obit is very eccentric. There is no life on mercury because of the great temperature differences between day and night. Venus is earth’s neighbor, and it is approximately the same size as the earth. However, the surface of Venus is very hot which results from the thick clouds surrounded the planet. The clouds are composed of almost pure carbon dioxide which prevent heat from going out of the planet. Earth is the cradle of creature and maybe it is the only planet on which there are lives. The favorable conditions on earth such as the regular day and night, the moderate temperate, the protective atmosphere, and the vast ocean make the existence of life possible. Mars is a red star. For many years novelists and scientists speculated about the possibility of life on the red planet because mars is similar to earth in many ways. For example, a day of mar is 24 hours plus several minutes. That is almost identical as earth’s day. Between the orbits of mars and Jupiter, there is a broad zone which has millions and millions of small bodies named asteroids. The size of these small bodies is usually less than 1000 kilometers in diameter. How the zone of asteroids is formed is still a mystery to people. One cannot tell Jupiter without the mention of its famous great red spot which is an area that can hold four earths. It is considered that there was a permanent tornado spiraling around the red spot. It would be better to say Jupiter is a failed star rather than a planet because it is a gaseous planet consisting mainly of hydrogen, helium, and other light substances. If someone describes a beautiful planet of the solar system with concentric rings in the plane of its equator, you can be sure to say it is the Saturn. In the outer part of the solar system there are Uranus, Neptune, and Pluto. Unlike other planets spin on the axis that is nearly upright to the imaginary revolving plane, the axis of the Uranus almost lies in the revolving plane. A well-known comet circling around the sun and arriving the nearest point to the sun every 76 years is Halley’s comet. The brightest celestial object we see in the night is our satellite-the moon. Many phenomena on earth such as approaching and receding of tides has close connect with the moon.

On the first page of chapter three there is a sentence I like very much. “ The serenity of the night sky belies the universe’s violent nature.” Indeed living on the peaceful earth, we do not feel great changes taken place in the universe. There maybe a star thousands times of the sun exploring; however, what we could see is just a tiny bright spot. If we look into the remote sky in the night, we may feel the immensity and the vastness of the universe; thus, we may have a sense of being small and ask where are we. The exact address of our position is the earth in the solar system in the milk way in the local group of galaxies in the universe, so we are really alone. I do hope someday we could find extraterrestrial beings or they have a visit to us.