January 15
1955 – The first U.S. house to be both solar-heated and radiation-cooled started its system. Built in Tucson, Arizona, it was built at a cost of nearly $4,000 for labor and materials.
1969 – The first docking of two manned spacecraft took place between the "Soyuz 4" and "Soyuz 5." The spacecraft formed what was termed "the world's first space station" with a crew of four aboard. They remained docked for four and a half hours (three orbits of the Earth). During that time, two cosmonauts space walked from "Soyuz 4" to "Soyuz 5," becoming the first to return to Earth in a different spacecraft from the one in which they went into space.
2005 – The "SMART-1" lunar orbiter discovers elements such as calcium, aluminum, silicon, iron, and other surface elements on the Moon.
The average dog is as smart as a two-year-old child.
