ORONO — Tides would be higher and days would be longer if the moon were closer to Earth, a University of Maine professor says in a book that takes readers to where science and speculation meet.

The book by Neil Comins, a professor of physics and astronomy, poses a number of scenarios that would exist if the solar system were different.

For example, if the moon did not exist, the Earth would rotate three times faster, causing shorelines to recede and creating movements in the atmosphere that would create powerful, sustained wind storms, says Comins’ book.

But if the moon were closer to Earth, tides would be extreme and the planet would rotate more slowly, creating longer days, says “What If the Moon Didn’t Exist? Voyages to Worlds the Earth Might Have Been.”

Besides analyzing ways in which different circumstances would have affected life on Earth, the book speculates on what the future holds for the planet.

Its final chapter moves beyond the realm of “what if” and takes a serious look at what effects changes in the atmosphere, such as ozone depletion, could produce.

“I hope readers will gain a new perspective on the world through this work,” Comins said.

Written in a way that might appeal to fans of Stephen Hawking and other theoretical scientists, Comins’ book extra- polates “what might have beens” from a factual base.

The scenarios are based on scientific principles and are not created like science fiction; Comins says he wrote his book “on the boundary between fiction and science.”

Comins’ book, which he describes as speculative astronomy, is expected in bookstores in the next few weeks.