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I have been trying to find this book for years to share with my kids, it would have been from the 90s. It was young adult sci-fi. The cover had a boy falling and a silver orb floating next to him.
The story is about a kid who gets pulled out of his reality right as a car accident happens, and I believe that they replaced him or his body with a clone, Millennium style. The world he is pulled into is covered by a dome, and run by silver orbs. The weather is controlled and it only rains on certain days, at the same time, with no thunder or lightning because it scares to kids and old folks.
The people are forbidden from leaving the dome, so of course the boy and a friend he makes do just that and adventure ensues. I can't remember the end of the book.