1. The "earth mother" or "mother earth": Gaia is the embodiment of the Earth as being fertile, encouraging, supporting and loving mother.
2. A Gaia space craft that is on a "Gaia mission" whose main goal is to make the largest, most precise three-dimensional map of our Galaxy by surveying an unprecedented one per cent of its population of 100 billion stars.

Astronomers will have the challenge of dealing with a flood of data when Gaia begins its work in 2012. Even after being compressed by software, the data produced by the five-year mission will fill over 30 000 CD ROMs. This data will be transmitted "raw" and they will need processing on Earth to turn it into a calibrated set of measurements that can be freely used by the astronomical community.

For more details about Gaia or Gaea, go to Earth, Words from the Myths.

1. Literally, dry land, earth: The old flower pot in the garage was made of earthenware or terra cotta, in which the earth had been baked in an oven.
2. Any of the light-colored highland or mountainous areas of the moon or of a planet: When he looked through the telescope, James could view the terra on the closest planet to Earth.

This fair land is the gift of God.

May the earth rest lightly upon thee.

An ancient inscription often found on Roman tombstones.

It is pleasant when safe on the land to watch the great struggle of another out on a swelling sea, amid winds churning the deep. -Lucretius

Translation: "Receive, O Earth, what was taken from thy body."

Epitaph of Pope Gregory the Great.

An imaginaty or supposed continent that showed up on European maps between the 15th and 18th century: Terra Australisis is also known as, Terra Australis Incognita, Latin for "the unknown land of the South".

It was introduced by Aristotle. Aristotle's ideas were later expanded by Ptolemy, a Greek cartographer from the first century A.D., who believed that the Indian Ocean was enclosed on the south by land.

1. A hard, semifired, waterproof ceramic clay used in pottery and building construction; terracotta: The couple decided to use tiles made of terra cotta for the floor in their new house.
2. Ceramic wares made of this material: The terra cottas were made of porous clay and fired or baked at a low temperature.

A historic type of lamp made from an unglazed, lightweight clay material that is typically red in color: Terra cotta lamps are believed to have been first used in ancient Greece in about 600 B.C.

1. Solid ground, dry land in contrast to water or air: Grace was very nervous on the flight from Canada to France and was very happy to be able to put her feet back on terra firma once again after arriving safely at the airport!
2. Etymology: from Modern Latin terra firma, "firm land"; from Latin terra "earth, land" + firma, "strong, steadfast". © ALL rights are reserved.

Go to this Word A Day Revisited Index
so you can see more of Mickey Bach's cartoons.

1. An unknown land; an unexplored region: Before people existed, the world had only terrae incognitae.
2. A new or unexplored field of knowledge: The expression terra incognita is often used in referring to matters about which one is uninformed, e.g. "I don't think I can do this because it is terra incognita to me."

Land that does not belong to anyone; empty land; no-man's land: In Australia, the idea and legal concept that when the first Europeans arrived in Australia, the land was terra nullius and not possessed by any one, and therefore open to settlement. It has been judged not to be legally valid.