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Of all the different ways that the Earth can be destroyed what ways is the most likely that could happen?

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closed as too broad by James K, StephenG, Reinstate Monica, Mike G, Jan Doggen Oct 5 '18 at 7:47

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    $\begingroup$ Are you asking about a scenario likely to happen in, say, the next 100 years or for the rest of the life of Sol? If the latter, then the transition of Sol into a red giant is not just likely, but almost certain. $\endgroup$ – BillDOe Oct 4 '18 at 20:12
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    $\begingroup$ I would guess a coronal mass ejection. $\endgroup$ – peterh says reinstate Monica Oct 4 '18 at 20:31
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    $\begingroup$ Red giant phase won't destroy Earth, it will merely make it uninhabitable for most lifeforms. A coronal mass ejection would not even cause a mass extinction. $\endgroup$ – Reinstate Monica Oct 4 '18 at 22:56
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    $\begingroup$ @Chappo My understanding is that there is some disagreement about exactly how large the Sun may grow to in that phase. Some models suggest taht eventually Earth's orbit would be inside the Sun's atmosphere, some don't. $\endgroup$ – StephenG Oct 5 '18 at 3:29
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    $\begingroup$ Sorry, this question is way too broad. Phil Plait (from Bad Astronomy) wrote an entire book about it: Death from the skies $\endgroup$ – Jan Doggen Oct 5 '18 at 7:47
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Asteroid impacts are a possibility, but a killer asteroid typically affects the Earth every few dozen million years. This would probably destroy all life as we know it, but life will probably nonetheless persist. Statistically, by 500,000 years from now, we should have been hit by an asteroid 1 km in diameter, and 100,000,000 years from now, we should have been hit by one that is the size of the one that killed the dinosaurs. Statistically it's very unlikely we will get one that completely obliterates the Earth, causing it to be completely and utterly destroyed.

Gamma-ray bursts may irradiate the Earth to the point that complex life will no longer be able to survive, and only very resilient organisms like waterbears may live. At some point in the next 300,000 years, WR 104 is expected to go supernova, and if the poles are somewhere around 12 degrees or lower we could be in the path of the supernova. We aren't 100% sure what its axis is angled at though. Either way, it won't actually destroy the Earth, but just irradiate it.

In roughly 7.5 billion years, the Earth will probably have been destroyed by falling into the Sun, as it engulfs the inner planets. This is nearly certain, but if somehow, the Earth-Moon system were to survive, then 50 billion years from now, the Earth and Moon will have become tidally locked. Then the Sun would extract angular momentum from the system as a white dwarf, and will cause the Earth's spin in accelerate and the Moon's orbit to decay. If this happens, then roughly 65 billion years from now the Moon will crash into the Earth, which would probably destroy it.

Keep in mind that there are many more ways that life as we know it could end, but these are not cosmic disasters, but are geologic and biological disasters, so they are not included. Generally speaking, it's very hard to completely destroy the Earth.

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