Pat Shingleton: "The Bolt and Earthshine..."
I recently visited with Fred Gwyn and the lightning that accompanied a thunderstorm last Sunday evening. The average lightning bolt is five times hotter than the surface of the sun, lasting less than 200 milliseconds. Cloud to ground lightning forms when a bolt of energy ejects from the storm cloud, meeting another bolt rising from the ground. The flash occurs when those two bolts collide and return to the cloud. Tim Samaras has been studying lightning for many years and is obsessed with capturing the earliest images of a lightning strike and does so with an incredibly large camera. Samaras believes that lightning and tornadoes are the final links of meteorological understanding and his 1600-pound-high-resolution, high-speed camera captures lightning photos that provide answers and save lives. Known as Kahuna, it’s the highest resolution and speed-camera in the world, resting inside Samaras’ mobile laboratory. From one flash to another... "Earthshine" is visible to the eye during a crescent moon. Leonardo da Vinci first explained the phenomenon whereby the moon acts like a giant mirror, showing the sunlight reflected from Earth. The brightness of the "Earthshine" measures the reflectance of the Earth. Scientists verify the Earth's climate is driven by the net sunlight it absorbs. They report that up to 20 percent of the reflectance has seasonal variations and have also verified a 2.5 percent decrease has occurred during the last ten years. If the Earth reflected 1 percent less light, the effect would be significant enough to be a concern for global warming. In the early 1900s. French astronomer Andre'-Louis Danjon began the first quantitative observations of "Earthshine." This method was dormant until 1991. The intensity of the "Earthshine" is measured at the Big Bear Solar Observatory in California.