- Jacques Descloitres, MODIS Rapid Response Team, NASA/GSFC
- On May 22, 2002, Svalbard, Norway, tucked inside the Arctic Circle, was showing no signs of spring on land, while in the Barents Sea, ice had begun retreating from the western coastline. This series of images shows the thawing of the sea ice around Svalbard, and also shows snow retreating from the landscape. Patches of brown are showing through, especially along fjords and inlets. Some images show blooms of marine plants called phytoplankton, which create colorful blue and green patterns on the ocean surface.
- Regular tetrahedron (Wikipedia)
A regular tetrahedron is a tetrahedron in which all four faces are equilateral triangles. In other words, all of its faces are the same size and shape (congruent) and all edges are the same length. A convex polyhedron in which all of its faces are equilateral triangles is the deltahedron. There are eight convex deltahedra, one of which is the regular tetrahedron.
