A girl has wondered her entire life whether life exists elsewhere in the universe. It becomes an obsession of hers. She imagines a planet far away, where sentient, intelligent beings exist in a sort of fantasy world, untouched by war or strife. When she finds a strange-looking rock in her yard, she studies it extensively, with the help of her father, a scientist. What they discover astounds them both. The rock is made of a mineral not found on the planet, and it is faintly radioactive. They take it to a lab to get it more closely examined, where it is determined that it is indeed from outer space. Buried inside the rock is a very unnatural-looking contraption- appearing to being the remains of something made by intelligent hands- melted, twisted, and burned.

Scientists around the planet rush to come up with possible explanations, and they conclude that the rock must have come from a distant planet. But what was the contraption? How did it get inside the rock? How did the rock come to land on their planet?

A few months later, they get their answer- somewhat. Radio transmitters across the planet pick up a strange sound, unlike anything anyone's ever heard. Some scientists say it sounds like someone screaming for help, others say it is merely a technical flaw in the systems.

Meanwhile, the main character of the story dreams about her far-off world. Except this time, it is quite a different place. Little does she know that her dreams were once reality.

In her dreams, she is transported back one-hundred million years before, to a planet orbiting a star far away. The planet is inhabited by a race of beings who call themselves humans. She finds them rather likable, and she thinks that they create beautiful things. However, they have also created very dangerous things that they call nuclear bombs. The humans are mad at each other. They are nervous, they keep looking at the skies, saying "they've done it now." In despair, a group of scientists send a final radio message deep into space, pleading for help futilely. Then the bombs start to fall. They start a chain reaction of explosions that shake the planet so much that huge chunks of rock fly out into space, carrying faint traces of the civilization that once inhabited the planet with them.

Terrified, the main character wakes up.

We are indeed aliens.

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Until the end of times.

Other than that, I think this concept would make a huge political is social statement if written well.  Nice job.