I read this when I was a child (late 90's to early 00's) so my memory of the details is a bit hazy, but the story concerned an alien race making contact with humans.

The main details I recall are that the aliens had not had predators on their planet (?) and so had not evolved to be competitive, and that they discussed with humans that their space-travel technology was based on the idea that the Law of Conservation of Matter/Energy was slightly wrong, and that the largely unnoticed destruction of minuscule amounts of stuff created gravity, a process they induced artificially for faster-than-light travel.

I had thought it was by Arthur C. Clarke, but none of his titles are ringing a bell with me. Any ideas?

2 Answers 2


This sounds like the Giant Series by James P. Hogan. Specifically, the 2nd book in the series the Gentle Giants of Ganymede.

In it, the Ganymeans (so called because their ship was first discovered on Ganymede) are a race that evolved in a world (Minerva) which did not have any predators. Hence, they never developed many of the aggressive traits of humans.

From page 209 of the Giants Novels compendium of the first three books in describing the reaction to the gravity wave pulse physics used by the Ganymeans worked:

"This account caused consternation among the scientists from Earth who were present. Hunt voiced their reactions by asking how some of the fundamental laws of physics--conservation of mass-energy and momentum, for example--could be reconciled with the notion of particles being able to vanish spontaneously whenever they chose. The cherished fundamental laws, it turned out, were neither fundamental, nor laws at all."

A synopsis of the series can be found at the following Wiki site.

BTW, the site also discusses the relationship of Hogan to Arthur Clarke. A tie-in which might be reminding you of Clarke is that the cover of the first novel in the Giants series (Inherit the Stars) starts with a startling discovery on the moon. A skeleton 50,000 years old.

Gentle Giants of Ganymede

  • It all comes flooding back! Thank you. I know I read Inherit the Stars and Gentle Giants.
    – Chris Lutz
    May 4, 2013 at 3:14
  • 1
    Glad I could help. I first read it when I was probably about your age when you read it.....but when it first came out in 1977 so yup, my cue to feel old :-)
    – beichst
    May 4, 2013 at 3:56
  • I think you mean "James Hogan" - though the Paul Hogan version would be fun, I'm sure, and very Australian
    – Andrew
    Mar 1 at 1:00
  • TY for catching the error Andrew. I have corrected.
    – beichst
    Mar 1 at 13:33

Childhood's End is an Arthur C Clarke novel on a lot of high school reading lists. It involves an alien species coming to Earth to help bring the Human race in to it's place as part of a greater civilization.

  • I'm quite familiar with Childhood's End - I've been meaning to reread it - and that's not it. Thanks, though.
    – Chris Lutz
    May 4, 2013 at 2:59

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