Chapter 14, Problem 12STP

Summary Introduction

To determine:

Initial atmosphere of earth lacked oxygen.

Introduction:

The early atmosphere of earth was rich in neon, water vapor, ammonia, and methane and it lacked oxygen. When earth was formed, it was a mix of solids and gases and almost lacked an atmosphere. The surface of the earth was molten and the volcanoes mainly spewed gases that contained methane, hydrogen sulfide.

Explanation of Solution

The scientists inferred that oxygen was absent from the early atmosphere because the early earth experienced frequent volcanoes, meteorites, and asteroids. No life existed on earth for the first billion years and the early atmosphere was not suitable for life. Although water vapor was present but there was no oxygen. The repeated volcanic eruptions ejected water vapor, hydrogen carbon dioxide and nitrogen into the atmosphere. The lack of any fossil record from these geologic periods suggest that no life could have survived that period without the presence of oxygen on earth.