“I don’t know that either. It depends. We’re protected, to some degree, by the barrier, but how effective is that protection? But there are some unavoidable facts. The sun is mortal, like every other star. It burns hydrogen and it expands and gets hotter as it ages. The Earth exists in a sort of habitable zone in the solar system, and that zone is moving steadily outward. Like I said, we’re protected, we’re okay for the time being no matter what. But eventually the Earth will be inside the heliosphere of the sun. Swallowed up by it. Past a certain point there’s simply no going back.” “How
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