Mapping the Martian home of life evidence The chemical and physical properties of meteorite ALH84001, which has revealed signs of simple organisms on ancient Mars, enable a planetary scientist to identify two craters on that planet's surface where the meteorite may have originated. Brain may make bright decisions early At the earliest stages of visual processing, the brain interprets the brightness of what is seen by considering contrasts between light and dark areas, a tactic that sometimes creates illusions about the absolute brightness of surfaces.
Many animals have striking colors and markings that warn their predators that they taste bad.
These traits evolved first in unpalatable creatures living in family groups, a new study suggests. Nitric oxide, the biochemical linchpin in a host of essential bodily processes, may also guard against the ravages of malaria. Some comets that are frequent visitors to the inner solar system may only be fragments of the icy bodies that assembled during the birth of the solar system. The placebo effect from any of several currently popular antidepressant drugs proves considerably more influential than the pharmacological actions, according to a new statistical analysis of 39 prior studies. A computer model suggests that saving adult rather than baby cheetahs is far more effective at boosting the declining population.