Surveyor data show a giant dust storm on Mars.
Credit: MGS/NASA

A model of how nanobiotics (tubes) disrupt bacterial membranes.
Credit: Ganz et al.

The immune system attacks joints in rheumatoid arthritis.
Credit: Arthritis Foundation

~~All About Asteroids~~ Portrait is of Giuseppe Piazzi pointing to Ceres, the first known asteroid, which he discovered at Palermo Observatory, in Italy. At a recent meeting to commemorate the bicentennial of Piazzi's discovery, scientists discussed the latest findings about the more than 26,000 asteroids now known. (Portrait: G. Velasco, © Palermo Observatory)

View of the rocky seacoast in Santa Flavia, Italy, not far from the Palermo Observatory.
Credit: Cowen

Three views of the surface of the asteroid 433 Eros, which the NEAR Shoemaker craft orbited for a year and then landed on in February.
Credit: NEAR/APL

Cloud of particles indicates the known population of the asteroid belt (see also http://ssd.jpl.nasa.gov/orbit_diagrams.html).
Credit: P. Chodas/Caltech, JPL

Giuseppe Piazzi used the Ramsden circle to discover the first known asteroid.
Credit: © Palermo Observatory

Palermo Observatory, framed by seacoast mountains.
Credit: © Palermo Observatory

Simulation of a collision between two rubble-pile asteroids, one depicted in red, the other in green. Each asteroid has a diameter of 2 kilometers and is made of some 5,000 particles, each 100 meters across. The collision proceeded at 2.6 meters/second, the estimated speed at which rocky objects collided during early planet formation.
Credit: Richardson and Leinhardt

Coated with powdered moss, a drop of water floats on water.
Credit: Aussillous and Quéré/Nature

216 Kleopatra: A 7-centimeter-long plastic replica.
Credit: Design Cast Studios

The highest-resolution radar image of an asteroid reveals that 1999 KW4 consists of two orbiting bodies. The smaller body is about 400 meters in diameter.
Credit: Margot/Caltech

Despite the variety in looks, the butterflies in the top row represent just local color variations of a single species, Heliconius melpomene. Each mimics a local color variation of Heliconius erato (bottom row). Photographs are from the Web site at http://abacus.gene.ucl.ac.uk/jim/jim.html.
Credit: Mallet