Transit of Mercury last four transits occurred on November 15, 1999; May 7, 2003; November 8, 2006; and May 9, 2016. The next will occur on November 11, 2019, and then on November 13, 2032. A typical transit lasts several hours. On June 3, 2014, the Mars rover "Curiosity" observed the planet Mercury transiting the Sun, marking the first time a planetary transit has been observed from a celestial body besides Earth. More generally, transits can also occur for Venus and were investigated in the context of searching for the hypothetical inner planet Vulcan. The most common observation to be made at a
NASA Earth Science chemistry, ocean and land ecosystems. It was a NASA scientist, Dr. James Hansen, who first alerted the world to the dangers of global warming due to greenhouse gases emitted by human burning of fossil fuels. Earth Science research also provides the foundations of understanding for the search for extraterrestrial life through the NASA Astrobiology Institute (NAI), in which the focus is often on the extreme conditions for life to survive. NASA Earth Science NASA Earth Science, formerly called the NASA Earth Science Enterprise (ESE), formerly called Mission To Planet Earth (MTPE), is a NASA research program "to develop a scientific