I invite you to use Google Earth and explore Mars. Look at the Martian southern hemisphere, and find an arid landscape littered with fossil valleys. These valleys speak of a remote past, when the red planet had water on its surface. There are thousands... click to read more

Unlike our own Blue Planet, Mars is currently too cold to sustain liquid water at its surface. At first glance, Mars 4 billion years ago should have been even colder. Back then, the Sun's brightness was only about 70% of what it is today. Yet... click to read more

Complex life on Earth requires oxygen. Understanding how oxygen levels have evolved on our planet can provide an insight into our own evolution and the possibility of complex life evolving elsewhere. Current theories suggest that Earth's O2 levels have risen three times over its 4.5... click to read more

More than two billion years ago, a group of microorganisms called cyanobacteria invented oxygenic photosynthesis, the process that turns light, carbon dioxide, and water into chemical energy and oxygen. Cyanobacteria are the plants of the microbial world - in fact, plants can perform photosynthesis because... click to read more

The presence of water is considered a necessary condition for the existence of life as we know it. Even if Mars is today a cold and arid place, there is ample evidence that things were different in the past, and that rivers, lakes and perhaps... click to read more