Can we ever reach the stars by conventional ships? No, it's not conceivable, except for the words themselves describing the actual thing: the nearest star is 24.9 trillion miles away from the Earth. It would take close to 79 million years to reach this star at the average speed of a rocket ship. Other notable places in the known universe are much farther. Travelling at the speed of light, it would take "only" about 4.4 years to reach the nearest star (Proxima Centauri). Physicists claim, based on our current knowledge, that matter-all matter-becomes infinitely massive as it approaches the speed of light. A ship, therefore, would not only become infinitely massive, it would require an infinite amount of energy to maintain it's speed. In other words, interstellar space travel for humans is either outright impossible, or insanely impractical and expensive as to be impossible.
The same physics would apply to alien races on alien planets, if they are out there.
