Las Tres Preguntas

A su paso por Saturno, las sondas Voyager tomaron, en los años 80 del siglo pasado, numerosas fotografías de sus anillos. Aquellas imágenes dieron pie, poco más tarde, a un extravagante experimento. Tras reproducir con suma precisión el diseño de los anillos en forma de surcos sobre un disco de vinilo, la audición desveló por sorpresa, en medio de una sucesión de frecuencias sin sentido, un fragmento de la Ofrenda musical, una de las composiciones más enigmáticas y esotéricas de Johann Sebastian Bach. Este sorprendente resultado podría interpretarse como un atisbo, singular y...

The United States grew rapidly from the time of the Louisiana Purchase to the building of the Transcontinental Railroad. All of this expansion came at the expense of Native American populations that had either lived in the region for centuries or been forced there from ancestral homes in the East. Tribes memorably fought on their own and together in an doomed effort to retain the land and a lifestyle that had long sustained their families. This book outlines some of the major conflicts of the Westward Expansion, and of the treaties and were signed, and often broken, by representatives of the...

What do people and other living things need to survive? Numerous images with simple labels show children all the things we need to live and be happy, from water and food to shelter and love. An activity asks young readers to describe how they have fun.

Wind Power: A waving flag, blowing leaves, a kite soaring through the skyall are moved by wind power. Wind is also our fast-growing source of energy. Find out how wind forms and the different ways we may use it in the future.