microbes

We Shouldn’t Worry About Contaminating Mars With Earth Microbes

We Shouldn’t Worry About Contaminating Mars With Earth Microbes

There may be no bigger question than whether we are alone in our solar system. As our spacecraft find new clues about the presence of liquid water now or in the past on Mars, the possibility of some kind of life there looks more likely. On Earth, water means life, and that’s why the exploration of Mars is guided by the idea of following the water.

Study pinpoints timing of oxygen’s first appearance in Earth’s atmosphere

Study pinpoints timing of oxygen’s first appearance in Earth’s atmosphere

Today, 21 percent of the air we breathe is made up of molecular oxygen. But this gas was not always in such ample, life-sustaining supply, and in fact was largely absent from the atmosphere for the first 2 billion years of Earth’s history. When, then, did oxygen first accumulate in the atmosphere?