Transit of Earth from Mars

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A transit of Earth across the Sun as seen from Mars takes place when the planet Earth passes directly between the Sun and Mars, obscuring a small part of the Sun's disc for an observer on Mars. During a transit, Earth would be visible from Mars as a small black disc moving across the face of the Sun. They occur every 26, 79 and 100 years, and every ~1,000 years, there is an extra 53rd-year transit.^{[citation needed]}