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The Future of Space Reconnaissance

As the superpowers continue to launch spy satellites, many nations are planning to orbit their own. Such extensive proliferation will complicate international politics into the next century

By Jeffrey T. Richelson

Self-Organized Criticality

Large interactive systems naturally evolve toward a critical state in which a minor event can lead to a catastrophe. Self-organized criticality may explain the dynamics of earthquakes, economic markets and ecosystems

By Kan Chen and Per Bak

The Protein Folding Problem

In theory, all one needs to know in order to fold a protein into its biologically active shape is the sequence of its constituent amino acids. Why has nobody been able to put theory into practice?

By Frederic M. Richards

Building the Cathedral in Florence

The octagonal dome of Santa Maria del Fiore, crowned by a lantern, orb and cross, is architecturally unique. Building the ensemble advanced the engineering and technology of the early Renaissance

By Gustina Scaglia

Worlds Around Other Stars

Theory and observation imply that planetary systems like our own should be common. Astronomical searches are closing in on planets that may orbit some nearby stars

By David C. Black


After more than 200 years, the mechanisms by which this venerable drug and its relatives achieve their wide range of effects have yet to be fully elucidated

By Gerald Weissmann

Coevolution of the Cuckoo and its Hosts

The cuckoo reproduces at the expense of other birds by laying its eggs in their nests. The strategy provokes an evolutionary arms race between parasite and host

By Michael Brooke and Nicholas B. Davies

Calculating Reality

Defying traditional designs, supercomputer architects are racing to build machines that are powerful enough to transform science

By Elizabeth Corcoran


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