solar aircraft

Solar Impulse: The Solar Impulse is the prototype of a fuel-free aircraft that is designed to circle the globe on sunlight alone.   Solar Impulse/Stephane Gros

As environmental concerns increasingly shape the direction of technology, the future of aviation is no exception: scientists have been looking to replace fuel-guzzling aircraft with solar-powered variants, an innovation that, in addition to passing the green test, would also enable planes to linger in the sky for longer.

2009 promises to be a big one for all things science and tech-related. From the LHC's big comeback to SciFi blockbuster sequels, you heard it here first. We bring you "The Future Now," and we don't mess around.

Read more of Popular Science's predictions for 2009.

Hybrid gasoline-electric vehicles began appearing late in the 19th century
from manufacturers such as the Compagnie Parisienne des Voitures Electriques
in France. In this country, an engineer named H. Piper applied for a patent
on a gasoline-electric motor combination on Nov. 23, 1905. By the time Piper
received his patent three years later, however, advances in gasoline engines
had begun to eclipse the performance of his and other hybrids. Among other