Flower Forest on an Earth locked with one side facing the Sun

Question

Long before this story begins, aliens swept through the Solar System and wept as they slammed the Moon into the Pacific Ocean and extremely slowed the Earth's rotation, making a day as long as a year. They said that they had to do this, though their motives remain unclear. In any case, they are gone now, and a Flower Forest (capitalized in the original) covers Europe and Africa on the side of the Earth that now faces the Sun.

The Moon lies partly embedded on the night side of the planet: in effect, an enormous mountain that reaches hundreds of miles above the atmosphere. It is the realm of a powerful scientist who can grant wishes, but he warns our protagonists that he is not all-powerful. There is a man who asked for high intelligence, and got it, but at the cost of staying plugged into a machine; he has no opportunity to use the intellect that he gained. And there are others in equally creative predicaments. Clearly, one must be careful what one asks for when bargaining with this man.

The protagonists ask if the historic rotation of the Earth in 24-hour days can be reestablished. Indeed it can, but after rotating for only twelve hours, the machine fails and the Earth stops spinning. The Flower Forest now faces away from the Sun, while the ex-lunar laboratory faces it, to the scientist's glee.

This was published as a novella or novel, perhaps in the 70s or 80s, in English. I suspect that Robert Silverberg may be the author despite the obvious errors in physics.

Answer 1

The book is The Twilight Man by Michael Moorcock.

This was originally serialised in New Worlds magazine, then published as a novel called The Shores of Death. I have the novel and while it matches some of the points in your description there are significant differences. It does have the Flower Forest and there is a search for the mad scientist, but there is no mention of the Moon being dropped into the Pacific ocean.

After some research I found that the original novel was completely rewritten and subsequently published as The Twilight Man, and this closely matches your description so this is probably the version you read. I don't have a copy of the Twilight Man, but there is a detailed description of the rewrite here. For example the article explains:

As Moorcock concedes, some readers ‘hinted – or stated bluntly, that the science wasn’t all it could be… they were right. I wasn’t convinced by the science either.’ So, instead of a rogue galaxy, for the novelisation there’s a race of space-dwelling creatures ‘seeking the edge of the universe’, who had ‘paused with casual ease to stop the world spinning’, a mischievous prank that creates a climatically divided Earth. Stilled on its axis, one hemisphere eternally facing the sun in everlasting day, leaving the other side facing away from the sun, perpetually frozen and inhospitable.

Other reviews mention points such as the Moon embedded in the dark side of the Earth's surface and the reversal of the day and night sides by the mad scientist Olono Sharvis.

So this is definitely the book you remember, though the publication history has made it a somewhat tortuous identification.