Glacial period

A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances. Interglacials, on the other hand, are periods of warmer climate between glacial periods. The last glacial period ended about 15,000 years ago. The Holocene epoch is the current interglacial. A time when there are no glaciers on Earth is considered a greenhouse climate state.

Quaternary ice age

Within the Quaternary glaciation (2.58 Ma to present), there have been a number of glacials and interglacials.

Last glacial period

The last glacial period was the most recent glacial period within the current ice age, occurring in the Pleistocene epoch, which began about 110,000 years ago and ended about 15,000 years ago. The glaciations that occurred during this glacial period covered many areas of the Northern Hemisphere and have different names, depending on their geographic distributions: Wisconsin (in North America), Devensian (in Great Britain), Midlandian (in Ireland), Würm (in the Alps), Weichsel (in northern central Europe), and Llanquihue in Chile. The glacial advance reached its maximum extent about 18,000 BP. In Europe, the ice sheet reached northern Germany.

Galactic North

Galactic North (ISBN 0-575-07910-X, published by Gollancz) is a collection of short stories by the science fiction author Alastair Reynolds. It comprises most of Reynold's short stories and novellas set in the Revelation Space universe.

Stories

Reynolds states in the afterword to the collection that the stories are set in rough chronological order, with "Great Wall of Mars" occurring around AD 2200, whilst Galactic North extends to AD 40 000

Summary of short stories

"Great Wall of Mars"

In this short story, we meet Nevil Clavain, one of the protagonists of the Revelation Space cycle, Galiana, the founder of the Conjoiner faction, and Sandra Voi, an important person in the Demarchist faction.

The story begins on Deimos, where Nevil Clavain, a high-ranking officer in the Coalition for Neural Purity is preparing to go down to the surface of Mars. His brother, Warren, is pushing for war with the Conjoiners. Eventually, Clavain and Voi depart and fly down towards the Great Wall of Mars, which turns out to be a massive construction that completely envelops part of the planet's surface (enough to cover a city) and the atmosphere above it. As they descend, they are attacked by robotic "worms"- war machines from the previous war with the Conjoiners. Clavain destroys the first worm, but more arrive and kill Voi. Clavain just succeeds in reaching the Conjoiner base. Galiana shows him around and he suggests that the Conjoiners and Coalition team up to attack Phobos, which is apparently infested by the worms. It is revealed that the Conjoiners are constantly deploying shuttles that try to escape the planet, but are always shot down by Coalition satellites. Clavain also meets Felka, a girl who was part of an experiment to further improve human intelligence by altering the brain in the womb. It failed miserably and Felka seems completely uninterested in anything except the mysterious game she is playing – she keeps waving her hands around in a pattern.