Mars collapse. In 2012, it was proposed that Valles Marineris is not just a graben, but a plate boundary where of transverse motion has occurred, making Mars a planet with possibly a two-tectonic plate arrangement. Images from the Thermal Emission Imaging System (THEMIS) aboard NASA's Mars Odyssey orbiter have revealed seven possible cave entrances on the flanks of the volcano Arsia Mons. The caves, named after loved ones of their discoverers, are collectively known as the "seven sisters". Cave entrances measure from wide and they are estimated to be at least deep. Because light does not reach the floor of most
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