Argyre quadrangle planet may have had. Water was probably recycled many times from the ocean to rainfall around Mars. Many places on Mars show channels of different sizes. Many of these channels probably carried water, at least for a time. The climate of Mars may have been such in the past that water ran on its surface. It has been known for some time that Mars undergoes many large changes in its tilt or obliquity because its two small moons lack the gravity to stabilize it, as our moon stabilizes Earth; at times the tilt of Mars has even been greater than
The Living Cosmos about the setting of the Earth and the events that have occurred on this planet. Subsequent chapters consider the origin of life on Earth, and the physical extremes to which life as adapted. In astrobiology, it pays to think “outside the box” and imagine how strange life might be or whether post-biological evolution is possible, where the basis is mechanical or computational. A chapter on evolution shows how it is affected by the cosmic environment. Possibilities of life in the Solar System are considered next, with emphasis on Mars, Titan, and outer moons harboring liquid water. Next is a summary