UFO does not exist, because is too far for UFO to fly to earth,
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1 t9 E! b9 A* n |) z, z! i公仔箱論壇light travels @300,000km per second, the distance from other planet has live forms may be more than 1 million light years公仔箱論壇) Z, W8 T5 B/ S- q, ?' G' c! |
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distance is the limitation for travel |