1899: The first ship-to-shore wireless message in U.S. history is sent by Lightship No. 70 to a coastal receiving station at the Cliff House in San Francisco.

“Sherman is sighted,” the message said, referring to the troopship Sherman, which was returning a San Francisco regiment from the battlefields of the Spanish-American War. It marked the first use outside England of this technology, still in its infancy.

The name most closely associated with the invention of wireless telegraphy — what we now know simply as radio — is Guglielmo Marconi, but as with so many technologies, there were a number...

Inspired by a recent trip to Yellowstone National Park, this gallery contains some of the country's most spectacular national parks, as seen from space.

Yellowstone's geothermal features are strange enough from the ground, but from orbit they seem even more incongruous (above). The Landsat 7 image below shows Yellowstone Lake and the entire park in false color, which highlights certain features that might not stand out in true color. Water appears dark blue or black, and snow is light blue. Grass fields appear light green, the dark red-and-green is mature forest, and young forest, such as has...