30 March 2012
Wikipedia ~ "In physics, a fluid is a substance that continually deforms (flows) under an applied shear stress." Most people equate fluids with liquids, but fluids also include gases, plasmas, and plastic solids. Did you know that glass, over time and under the influence of gravity, has fluid properties?
NASA's Goddard Space Flight Center has assembled a finely-detailed animation of the sea surface currents which tend to be the main drivers of heat, salinity, and carbon transport within the world ocean. Although the 3-minute animation only shows surface movement, the computer model includes currents at all ocean depths. To view the full 20-minute version, check out NASA's website here.
A similar website called Wind Map shows swirling wind patterns across the U.S. ~ better still, this depiction is in real time, updated every hour. You can "zoom in on particular regions of the country, use hover-over text to find the wind velocity at precise geographical coordinates, and explore a variety of interesting wind patterns from the past". For those who study weather, from pilots to farmers to meteorologists, this is a useful tool. It would be even more useful if it showed winds aloft at various altitudes. Hopefully that is in the offing.
We rarely think of stars as being fluid, but they assuredly are ~ on a monumental scale. Each star is an incredibly complex and evolving pattern of gas and plasma flows, and stars in groups (galaxies) exhibit a stately, slow-motion fluidity as they perform their whirling dance through space. A new composite photo of our Milky Way galaxy shows more than a billion stars. The image is static, but one can easily imagine their swirling motion over cosmic time. (Note ~ click on the horizontal image halfway down the page here to view the full galactic image.
Finally, courtesy of my friend Bill, you can view the path a solid object which travels a serpentine, almost-fluid path at Take a Train Through Switzerland, a project which uses Google Maps street view. Safe travels!