Determining the composition of Earth's current atmosphere is relatively straightforward, using direct measurements, remote sensing via satellites, and sampling by aircraft. It is far more complicated to determine the composition of Earth's past atmosphere, going as far back as 4.6 billion years ago. Bubbles in... click to read more

The whales, dolphins, and porpoises (generally called "cetaceans") that we know today are fully aquatic mammals, spending their entire life in the water. Whereas the forelimbs of these hydrodynamic animals are transformed into flippers, mostly used for steering, their hind limbs are highly reduced, and... click to read more

The physical and chemical evolution of planets relies on certain volatile elements, such as Hydrogen (H), Carbon (C), and Nitrogen (N). For instance, on Earth volatile elements influence magma chemistry, volcanism and the evolution of our atmosphere and climate. Perhaps most important, the presence of... click to read more