When Earth formed about 4.5 billion years ago, its atmosphere was nothing like it is today. At that time, the atmosphere and ...

Chemical composition of ancient rocks Iron sulfide can only exist in rocks that were formed before there was oxygen in the atmosphere. Rocks containing iron oxide can only form if oxygen is present.

Urey (1893-1981) published an elaboration of Haldane's theory, suggesting that Earth had formed from a cold stellar dust cloud. Its early atmosphere was then roughly similar to that of the rest of ...

Just three months later, it fell out of orbit. As Sputnik hit the upper atmosphere at incredible speed, the friction would have caused it to heat up and almost entirely burn off. Some small ...

Chemical composition of ancient rocks Iron sulfide can only exist in rocks that were formed before there was oxygen in the atmosphere. Rocks containing iron oxide can only form if oxygen is present.