Mercury's surface looks similar to our Moon's. Each is heavily cratered and made of rock. Mercury's diameter is about 4800 km, while the Moon's is slightly less at about 3500 km (compared with about 12,700 km for the Earth). But Mercury is unique in many ways. Mercury is the closest planet to the Sun, orbiting at about 1/3 the radius of the Earth's orbit. As Mercury slowly rotates, its surface temperature varies from an unbearably cold -180 degrees Celsius to an unbearably hot 400 degrees Celsius. The place nearest the Sun in Mercury's orbit changes slightly each orbit - a fact used by Albert Einstein to help verify the correctness of his then newly discovered theory of gravity: General Relativity. The above picture was taken by the only sp ...

The island of Socotra is one of the most isolated non-volcanic landforms in the world. Sitting 240 km east of the Horn of Africa and 380 km south of the Arabian Peninsula, its geographic isolation over millions of years has ensured that a third of its plant species are found nowhere else on Earth. Clockwise from the top are dragon blood trees, desert roses, and a native succulent, Dorstenia gigas. ...

Four species of legless lizard have been identified in the sand dunes of Antioch, California. This picture introduces Anniella grinnelli, one of the recently found species. It has a bright yellow belly and a lilac back with deep purple lines, and was named after Joseph Grinnell, the first director of the Berkeley Zoology Museum.

Carpenter ants (Camponotus cylindricus) are found in Borneo and expel the lethal sticky substance to defend their colony. Both ant and invader are killed in these attacks; they fall from the canopy as a pair into the leaf litter below, to eventually be eaten by something. Most of the bodies of the south-east Asian Camponotus cylindricus ants are for storage of the deadly secretion. The insects react quickly - when researchers lightly touched them with forceps their abdomen walls ruptured. ...

This is the giraffe weevil from Madagascar, which, as you might have guessed, gets its name from its long neck. Males use their extra long necks for fighting, while females use theirs to roll a leaf nest, into which an egg is laid during reproduction.