Stories tagged atmosphere


Aurora, 12/14/06: Photo by Eugene Dillenburg.
Aurora, 12/14/06: Photo by Eugene Dillenburg.

Did anybody see the northern lights this week? I went out Thursday night, and it was awesome!

I headed out about 11:00 pm EST. Temps in the mid-40s -- not bad for mid-Michigan in mid-December! I walked a couple of blocks to a park near my apartment which I knew had a big field surrounded by trees, and no lights. On my way, I could see the sky glowing a pale green, as if the lights of the city were reflecting off a low cloud. Only, there were no clouds last night, and there's nothing but farmland north of Lansing.


Scientists at Rutgers University in New Jersey have discovered that the amount of oxygen in the Earth's atmosphere has more than doubled over the last 205 million years.

By studying samples of seafloor material going back millions of years, they determined that the atmosphere was only 10% oxygen during the time of the dinosaurs. It rose as high as 23% by 40 million years ago. (The air is 21% oxygen today.) That's about the time that really large mammals, like elephants and rhinos, started to emerge.

Oxygen levels may have affected the evolution of mammals. These warm-blooded creatures need three to six times as much oxygen as a reptile of the same size. The lack of oxygen may have prevented them from growing very large. But as oxygen levels increased, mammals could start getting bigger.