Transit of Mercury

A transit of Mercury across the Sun takes place when the planet Mercury comes between the Sun and the Earth, and Mercury is seen as a small black dot moving across the face of the Sun.

Related Topics:
Transit - Mercury - Sun - Planet - Earth

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Transits of Mercury with respect to Earth are much more frequent than transits of Venus, with about 13 or 14 per century, in part because Mercury is closer to the Sun and orbits it faster.

Related Topics:
Mercury - Transits of Venus - Sun

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Transits of Mercury can happen in May or November. November transits occur at intervals of 7, 13, or 33 years; May transits only occur at intervals of 13 or 33 years. The last two transits were in 1999 and 2003; the next two will occur in 2006 and 2016.

Related Topics:
1999 - 2003 - 2006 - 2016

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During a May transit, Mercury is near aphelion and has an angular diameter of 12"; during a November transit, it is near perihelion and has an angular diameter of 10".

Related Topics:
Aphelion - Angular diameter - Perihelion

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The first observation of a transit of Mercury was on November 7 1631 by Pierre Gassendi. He unsuccessfully attempted to observe the transit of Venus just one month later, but due to inaccurate astronomical tables he did not realize that it was not visible from most of Europe, including Paris. A transit of Venus was not observed until 1639, by Jeremiah Horrocks.

Related Topics:
November 7 - 1631 - Pierre Gassendi - Transit of Venus - 1639 - Jeremiah Horrocks

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