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Our earth is very old, an old warrior that has lived through many battles. Nevertheless, the face of it is still changing, and science sees no certain limit of time for its stately evolution. Our solid earth, apparently so stable, inert, and finished, is changing, mobile, and still evolving. Its major quakings are…
Briefly, a radioactive isotope is a kind of atom which decays into a different kind of atom: for example. one called uranium-238 turns into one called lead-206. Because we know how long this takes to happen, we can think of the isotope as a radioactive clock. Radioactive clocks are rather like the water clocks and…
The history of Earth's climate is one of the more compelling arguments in favour of Gaia's existence. We know from the record of the sedimentary rocks that for the pst three and a half aeons the climate has never been, even for a short period, wholly unfavorable for life. Because of the unbroken record of life, we…