earth and atmospheric sciences

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?

Rogue wave ahead - New prediction tool gives 2-3 minute warning of incoming rogue waves.

Rogue wave ahead - New prediction tool gives 2-3 minute warning of incoming rogue waves.

Sailing history is rife with tales of monster-sized rogue waves — huge, towering walls of water that seemingly rise up from nothing to dwarf, then deluge, vessel and crew. Rogue waves can measure eight times higher than the surrounding seas and can strike in otherwise calm waters, with virtually no warning.