Dragon's Egg

Dragon's Egg is a 1980 hard science fiction novel by Robert L. Forward.

It is a first contact story about humans meeting the Cheela, a race of beings who live on the surface of a neutron star. Both races live at a different time frame - twenty-nine seconds for a human is the rough equivalent of a year for a Cheela. Was followed by a sequel, Starquake.

Notable as a hard science fiction story in that the science tends to be the focus.

Tropes in this book:

 * Aliens Never Invented the Wheel: Wheels are never mentioned in the book: the Cheela use sleighs. While it's not explicitly stated, it's easy to surmise that, in the neutron star's extreme gravity, a technology where some part -- such as an axle -- needs to be lifted off the ground is not practical.
 * Alternative Number System: The Cheela use base 12, since they have 12 eyes.
 * Ancient Astronauts: That is, we are. The arrival of the human spacecraft is so slow from their standpoint they worship it as a god. By the time we actually make contact, the Cheela are a little smarter.
 * Anti Gravity: One of the first things the Cheela invent on their own. Notably, they develop it before flight -- it's actually the basis of their aerospace engineering, since in Dragon's Egg's gravity you can't get airborne without it.
 * Bizarre Alien Biology: The Cheela aren't even made from normal matter.
 * Blob Monster: The Cheela are sort of like amoebas.
 * Crystal Dragon Jesus: The story of Pink-Eyes.
 * Extra Eyes: 12, in a circle.
 * First Contact: Humans meeting the primitive Cheela.
 * First Contact Math: How the humans contact the Cheela.
 * Flat Character: The humans in this story who are visiting the Cheela have a few simple characteristics, but are nothing more than a device to bring the Cheela in. The Cheela are far richer characters.
 * Heavyworlder: One of the most extreme examples.
 * Innocent Aliens: The Cheela have as many differences between them as any race, but they don't mean any harm to humans.
 * Minovsky Physics: Pretty much all of the human technology that didn't already exist when the book was written is based on magnetic monopoles, particles that are actually discussed by Real Life physicists (though they remain hypothetical for now). Forward explains in great detail the physics behind the monopole-using tech. Which brings us to...
 * Mohs Scale of Science Fiction Hardness: A 5.5. It's considered to be a fine example of hard sci-fi.
 * No Antagonist: In terms of the overarching plot of First Contact. The Cheela go through a great deal of time and conflicts happen in each time period, but there is no Big Bad in the book.
 * A Pupil of Mine Until He Turned to Evil: Averted. The humans upload their encyclopedia to the Cheela who quickly outpace humans, but they take on the role of a good teacher instead.
 * Scavenger Hunt: The Cheela eventually surpass humanity and give them the secret of interstellar travel
 * Space Elevator: The Cheela need one of sorts to get off of the star.
 * Starfish Aliens: The Cheela are like amoebas, only with 12 eyes on stalks.
 * Technology Levels: Mostly averted. The Cheela's technological development is very loosely patterned after the mankind's, but their different environment imposes important differences. See Aliens Never Invented the Wheel and Anti Gravity above for more.
 * Technology Marches On: A bit for the humans, a lot for the Cheela.
 * Time Stands Still: That's about how the humans look to the Cheela.
 * Year Inside Hour Outside: For every twenty-nine human seconds, about a year goes by for a Cheela. (Reading this out loud at a normal pace from "Year Inside Hour Outside" to this point takes about six months of Cheela time.) A Cheela lifetime runs about 90 "greats" (approximately forty-four minutes) on average. One human character goes to bed annoyed that he'll be asleep for the Cheela equivalent of a millennium.