As is typical of the genre, Dragon's Egg attempts to communicate unfamiliar ideas and imaginative scenes while giving adequate attention to the known scientific principles involved.
The star's short-lived plasma jets are lop-sided because of anomalies in its magnetic field, and set it on a course passing within 250 astronomical units of the Sun.
The star contains about half of a solar mass of matter, compressed into a diameter of about 20 kilometers (12 miles), making its surface gravity 67 billion times that of Earth.
Its outer crust, compressed to about 7,000 kg per cubic centimeter, is mainly iron nuclei with a high concentration of neutrons,[1] overlaid with about 1 millimeter (0.039 inches) of white dwarf star material.
Large volcanoes, formed by liquid material oozing from deep cracks, can be many centimeters high and hundred meters in diameter, and will eventually collapse, causing starquakes.
Although one genius invents mathematics to calculate and measure the band's food supply, the situation is desperate and the clan's survival depends on the self-sacrifice of the oldest members.
The humans notice this novel and very regular feature, conclude that intelligent beings inhabit the star, and use a laser to send simple messages.
As her attempts to transmit from the civilization's territory are ineffective, she travels to a mountain range to transmit directly under the spacecraft – conquering the fear of heights that is instinctive for flattened creatures living in 67 billion g. The humans recognize her message and realize that the cheela live a million times faster than humans.
After reading an astronomy article, a cheela realizes that the supernova half a million human years ago created both their races.
Writer Robert L. Forward described being inspired by astronomer Frank Drake's suggestion in 1973 that intelligent life could inhabit neutron stars.
[2] Later Forward found an earlier letter in which he discussed the idea of high-gravity life in the Sun with science fiction novelist Hal Clement.
[16] Chris Aylott described it as "a minor classic of science fiction – one that shows off both the best and worst elements of hard SF.
He found the writing of the human cast dull, but appreciated Forward's ability to share his fascination with the cheela and to create communications between races that lived at vastly different speeds.
"[17] Lambourne, Shallis, and Shortland consider that the research and detailed construction of the scenario make Dragon's Egg an excellent example of hard science fiction.
[19] John Pierce also regarded Dragon's Egg as hard science fiction at its best, while Forward's later novel Martian Rainbow (1991) was the genre at its worst.
The novel even makes readers care about the fate of an unsympathetic cheela ruler, whose rejuvenation treatment fails catastrophically.
[20] Robert Lambourne regards Forward, especially in Dragon's Egg, as the successor of Hal Clement, whose Mission of Gravity exemplifies the most strongly science-based science fiction.