I believe (sentient) life exists, after all with such a mind-dazzling amount of galaxies, stars and planets out there I would find it extremely unlikely that ours is truly the only one where life has formed.
But I don’t believe they have the capability to fly to our planet. First, distances are massive, and travel is limited by the speed of light. There are theories to bypass the light speed limit, however I think no concrete proof that it’s possible yet, much less on a scale large enough to transport human beings. Not to mention economic feasibility. Second, out of all planets, many of them probably closer to their home, why come to this one
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