Scientific American Magazine

Last summer the first ever Mars rover found in situ evidence that the Red Planet may once have been hospitable to life

Groundbreaking work that began more than a quarter of a century ago has led to ongoing insights about brain organization and consciousness

A new type of laser that harnesses the energy of individual atoms reveals how light interacts with matter

Butterflies meet, woo and win their mates using seductive signals and clever strategies honed by evolution

Celebrated for his pendulum experiment in 1851, Foucault also produced decisive evidence against the particle theory of light, invented the gyroscope, perfected the reflecting telescope and measured the sun's distance

Worldwide, the populations most affected by the AIDS virus are often the least empowered to confront it effectively

Today's optimal treatments can work magic, but they are costly and onerous and do not work for everyone. What might the future bring?

HIV infection is particularly difficult to combat in the young

Altering behavior is still the primary way to control the epidemic

Unlike vaccines for many viruses, those for HIV may have to go beyond generating antibodies. Devising approaches that will fully activate the immune system is far from simple

Treatment may reduce the chance of contracting HIV infection after a risky encounter