|Spirit acquired this view of the Martian sunset from Gusev Crater on April 23, 2005. Using data from images such as this, scientists have learned that twilight on Mars is longer than on Earth, lasting for up to two hours before sunrise or after sunset. Dust high in the atmosphere scatters light to the night side of the planet. Similar twilights are seen on Earth following major volcanic eruptions.
Image Credit:NASA/JPL-Caltech/ Cornell/Texas A&M