I found the (short) story about a boy (or a man, probably, can't remember) in a collection of short sci-fi stories. I can describe the story a little, if that helps:-
The story starts out somewhere desolate, I think. There is a boy, who is walking around, when something like a tower erupts out of the ground and starts to pull everything around him (and him) inside. Inside, the interior goes down and he sees what looks like a flying dinosaur (dead) and a medieval knight (dead as well). Finally, stuff comes to a stop and somehow, there are spikes coming towards him. He realizes that there seems to be a puzzle near him.
He notices that it is a model of a solar system without the Earth, which seems to be the piece that he has to add. There is a blue ball near the model, and he puts it into the groove that seems to be where the Earth should go.
The spikes retract and an alien comes towards him and mind-speaks to him. The alien says that he has been hibernating since (I don't remember) and had come on Earth to find intelligent life. There was a computer that woke him as soon as it realized that the boy was intelligent and had passed the test.
He shows the boy his home planet's photographs (which have purple skies) and tells him that he came from Earth's nearest galactic neighbour. Which when asked, the alien replies is neither Mars, nor Venus.
The boy realizes it to be the moon, and tells the alien that the moon is dead and barren now, but the alien doesn't seem to want to believe.
The boy somehow manages to escape the tower and the alien, with his spaceship goes away.
Hint: I remember that the alien was blinded, or afraid of light from the boy's torch.
I read this story years ago and really want to know what the title was. I would like to know the title of the collection, if possible.