The Cosmic Fate of Earth
Assuming that human life on earth survives all the perils that are outlined in today’s media – food shortages, resistance to antibiotics, asteroid impacts and super viruses, the next challenge is to examine some inevitable dangers on a much larger scale but which are, fortunately, very far into the future.
Mario Livio, Astrophysicist from the Space Telescope Science Institute has outlined a number of cosmic events that could eliminate life on earth. The first may commence in about 1 billion years and involves a significant increase in solar electromagnetic radiation which would cause Earth to lose its oceans and revert to a lifeless state.
According to Livio, the second major event can be predicted with considerable certainty. In approximately 4 billion years, the Andromeda galaxy will collide with the Milky Way and it is hypothesized that this will change the Sun’s environment and have a direct effect on life on Earth.
Finally, in about 5 billion years, the hydrogen nuclear fuel in the Sun’s core will begin to deplete, it will evolve to become a red giant and its radius will increase by 100 times. Assuming that life managed to survive the previous two cosmic events, this is likely to be the finale with temperatures on Earth well above 1,000 Kelvin.
Given the time scale of these cosmic events, humans may have long left their Earthly abode and found habitation in far off galaxies.
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