Our Earth ~ Part I
You may be expecting some commentary on what the climate is doing to our tiny little home. I decided instead to present some facts, serious or merely curious ones, and let you make the comments and draw conclusions. In addition, NASA has helped me enhance some items with pictures, many from our orbiters in space. The full gallery can be found here.
1. The Namib desert (below) is kept dry by cold ocean currents coming off the Atlantic. It is known as the Skeleton Coast because, with so little water, shipwreck survivors don’t thrive there very long.
Credit: Johnson Space Center
2. Is Lake Chad shrinking or not? One study says probably. Lake Chad, in the desert just north of wet, tropical Africa, suffered under severe drought in the 1970s and shrank by an alarming amount. Approximately 50 million people depend on its fresh water. The study finds that despite wetter conditions in the 1990s, Chad did not regain its levels of the 1960s.
3. Desert “varnish” (below): The Tifernine dunes of Algeria were formed on a base of sandstone which trapped sand in layers up to 1500’ deep, and later, trapped metallic ores and clay from the eroding mountains nearby.
Credit: Johnson Space Center
4. Italy Changes Sides. Millions of years ago Italy, a piece of the African continent, drifted north and collided with Europe, folding up a little thing we call the Alps. This event was much more recent than, say, the forming of the old Ural Mountains.
5. Saudi Agriculture (below): Lush farms like these are springing up all over the Arabian desert. This is made possible by the huge capital investment the government has made in bringing up water from over a thousand feet down and purifying it.
Credit: JPL
6. Mekong Delta and the Effects of War: The delta, about 15 miles from Ho Chi Minh City, was a dense tropical forest before 1960, with mangrove and fishing villages on the coast. It now runs muddy from erosion due to the loss of trees – remember agent orange? What little forest that remains there is unmanageable due to the proliferation of unexploded ordnance.
7. Lake Baikal (below): Twenty-five million years ago plate tectonics opened up a crack in Asia 29,000 feet deep – think inverted Himalayas. The crack was filled with water creating the largest lake in the world, the 395-mile long Lake Baikal – as long as Pennsylvania is wide. The lake holds one-fifth of Earth’s fresh water.
Credit: Johnson Space Center
These entries were inspired Orbit, NASA Asgtronauts Photograph the Earth, by Jay Apt, Michael Helfort, and Justin Wilkinson; National Geographic Society, 1996.
October 2021