On a clear night, there is nothing to stop heat radiating from the ground out to space. You may notice that frost will form even though a thermometer on a wall shows a temperature of 33 or 34F. That is because the ground can get colder than the air above it, by radiating heat to space.
From Wikipedia, the free encyclopedia. The Truman Doctrine was an American foreign policy to stop Soviet imperialism during the Cold War. It was announced to Congress by President Harry S. Truman on March 12, 1947 when he pledged to contain Soviet threats to Greece and Turkey. No American military force was involved; instead Congress appropriated a free gift of financial aid to support the economies and the militaries of Greece and Turkey.
As a result, in 1947, President Truman issued the Truman Doctrine which stated that the United States would supply aid to any country as long as they pledged to be democratic. The Marshall plan was enacted in 1948 and it was similar to the Truman Doctrine except it provided financial aid to these countries....