Earth Gets a Warm Feeling All Over
(NASA, 2005) Last year was the fourth warmest year on average for our planet since the late 1800s, according to NASA scientists. To determine if the Earth is warming or cooling, scientists look at average temperatures. To get an "average" temperature, scientists take the warmest and the coolest temperatures in a day, and calculate the temperature that is exactly in the middle of those high and low values. This provides an average temperature for a day. These average temperatures are then calculated for spots all over the Earth, over an entire year.