Big Questions for UARS
Launched from the Space Shuttle Discovery on September 15, 1991, UARS orbited the Earth more than 78,000 times, using 10 onboard scientific instruments to collect data on a variety of chemicals, including carbon dioxide, ozone, chlorine, methane, nitrogen oxides and chlorofluorocarbons.
- How is the global earth system changing?
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Earth is currently in a period of warming. Over the last century, Earth's average temperature rose about 1.1°F (0.6°C). In the last two decades, the rate of our world's warming accelerated and scientists predict that the globe will continue to warm over the course of the 21st century. Is this warming trend a reason for concern? After all, our world has witnessed extreme warm periods before, such as during the time of the dinosaurs. Earth has also seen numerous ice ages on roughly 11,000-year cycles for at least the last million years. So, change is perhaps the only constant in Earth's 4.5-billion-year history.