How brains work, how brain imaging works: Astrocytes
Posted: 20 Jun 2008 08:29 AM CDT
Blood flow in the brain is linked to neuronal activity. Therefore, various 'brain scanning' techniques can be used to observe neuronal activity in the brain. This has led to an astonishing revolution in knowledge of how the brain works. Of course, you knew that already.
Also astonishing is that the reason for changes in blood flow in relation to what neurons are doing is unknown! We know this system works, but we don't know why!
Until now...
/////////////////Curiosities: Why does the sky turn green before a tornado?
June 6, 2008
Scott Bachmeier, a research meteorologist at the Cooperative Institute for Meteorological Satellite Studies at UW-Madison, says that particles in the air scatter light. In the day, the particles scatter more violet and blue light, but our eyes are more sensitive to blue light — that’s why the sky appears blue.
Thunderstorms, which can be the home of tornadoes, usually happen later in the day, when the sun is approaching the horizon. That creates a reddish tinge in the sky, as any fan of sunsets knows. But light under a 12-mile high thundercloud is primarily blue, due to scattering by water droplets within the cloud. When blue objects are illuminated with red light, Bachmeier says, they appear green.
////////////////////
No comments:
Post a Comment