Planet Earth BBC YouTube

Within the first billion years of Earth’s history, life appeared in the oceans and began to affect the Earth’s atmosphere and surface, leading to the proliferation of anaerobic and, later, aerobic organisms. Some geological evidence indicates that life may have arisen as early as 4. 1┬ábillion years ago. Since then, the combination of Earth’s distance from the Sun, physical properties and geological history have allowed life to evolve and thrive. In the history of life on Earth, biodiversity has gone through long periods of expansion, occasionally punctuated by mass extinction events. Over 99% of all species that ever lived on Earth are extinct. Estimates of the number of species on Earth today vary widely; most species have not been described. Over 7. 7┬ábillion humans live on Earth and depend on its biosphere and natural resources for their survival. Humans have developed diverse societies and cultures; politically, the world has around 200 sovereign states.



Beneath The Icy Crust Of Enceladus. The research paper written by scientists with the Cassini mission, published in the journal Science, suggests the presence of hydrogen gas. Hydrogen gas, that could potentially provide a chemical energy source for life, is pouring into the subsurface ocean of Enceladus from hydrothermal activity on the seafloor of this bewitching, distant moon-world. The GRAIL mission determined the internal structure of the Moon in great detail for nine months during 2012. Armed with this the new information, GRAIL astronomers were able to redefine the sizes of the largest impact basins on the lunar surface. So, the next time you're planning a big fishing trip, make sure you know when the moon sets and rises for that day and plan around it. You will find your fishing experience a much more rewarding one for having that bit of knowledge. I promise!