The Red Planet's Watery Past

New observations by rovers and orbiters indicate that liquid water not only existed on Mars, it once covered large parts of the planet's surface, perhaps for more than a billion years

The Ultimate White Light

"Supercontinuum" laser light has enabled the most precise frequency and time measurements ever and might drive optical data transmission rates to record speeds

Lucy's Baby

An extraordinary new human fossil renews debate over the evolution of upright walking

Cancer Clues from Pet Dogs

Studies of pet dogs with cancer can offer unique help in the fight against human malignancies while also improving care for man's best friend

Scientific American 50

Set Theory

Seeking the Neural Code

Learning how rats escape from cats also reveals how a storm of electrical pulses sweeping across the brain is translated into information

Weighty Matters

The century-old artifact that defines the kilogram, the fundamental unit of mass, is to be replaced by a more accurate standard based on an invariant property of nature

Swiss Re

Zurich, Switzerland A top insurer highlights the dire consequences that could result from global warming

Angela Belcher

Massachusetts Institute of Technology This eclectic investigator draws inspiration from nature's genius for building things at the nanoscale

Al Gore

U.S. Vice President The former presidential candidate is the preeminent spokesperson on climate change

On the Road to Green

Chemists and automakers mark progress toward environmentally benign fuels and vehicles

More Than Government Grants

Entrepreneurial ingenuity focuses on finding money and ideas to advance medical science

Unlocking Alzheimer's

Understanding the workings of a key protein may presage treatments

The Promise of the Mother Cell

Stem cell biology continues to hint at medical benefits to come

Beginning to See the Light

Two-dimensional light waves point toward optical imaging of viruses and the Invisible Man

Chicken-Wire Electronics

Carbon structures provide new devices and remarkable physics

Smart Tags Get Smarter

The next generation of electronic tags promises to outperform RFIDs

Growing Replacement Parts

Bioengineers can now cultivate blood vessels and other tissues from scratch

DNA Sequencing on the Cheap

Optical technology advances toward the $1,000 genome

Robots on the Move

Improved mathematical models and sensors endow robots with enhanced mobility

Material Progress

Designers have crafted new structures ranging from nanorods to mimics of mother-of-pearl

Sight Savers

Technology that could help the blind see is now in the laboratory

Of Brain Maps and Saving the Internet

An array of technologies are complemented by a push toward sensible public policy