Transit of Mercury on November 8, 2006 with sunspots #921, 922, and 923

Transit of Mercury (time lapse showing entire event)

Close-up of Mercury during the Nov. 8, 2006 Transit

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 more rapidly.

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 three transits occurred in 1999, 2003 and 2006 ; the next will occur in 2016.

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".

Grazing transits of Mercury

Sometimes Mercury only grazes the Sun during a transit. In this case it is possible that in some areas of the Earth a full transit can be seen while in other regions there is only a partial transit (no second or third contact). The transit of November 15 1999 was such a transit, and the previous one before that was on October 28, 743. The next such transit will occur on May 11, 2391.

It is also possible that a transit of Mercury can be seen in some parts of the world as a partial transit, while in others Mercury misses the Sun. Such a transit last occurred on May 11 1937, and the previous one was on October 21 1342. The next such transit will occur on May 13, 2608.

Simultaneous transits

The simultaneous occurrence of a transit of Mercury and a transit of Venus is extremely rare, and will next occur only in the years and .
In September 13, an almost identical event is predicted : a transit of Mercury and a transit of Venus will follow themselves, one after the other, in an interval of only 16 hours.

The simultaneous occurrence of a solar eclipse and a transit of Mercury is very rare. The next solar eclipse occurring during a transit of Mercury will be on July 5, 6757, and will be visible in Eastern Siberia.

Past and future transits

Although a spot on the Sun observed as early as 807 is believed by many experts to have been a transit of Mercury^[1], the first observation of a transit of Mercury was on November 7 1631 by Pierre Gassendi. Johannes Kepler had however predicted the occurrence of transits of Mercury and Venus some time before that. 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.

References

• Cunningham, Clifford J., "Mercury's Time to Shine," Mercury Sep-Oct 2006.

See also

• Astronomical transit
• Black Drop Effect

External links

• NASA: Transits of Mercury, Seven Century Catalog: 1601 CE to 2300 CE
• NASA: Image from the transit of Mercury in 2003
• Shadow & Substance.com: Transit of Mercury Animated for November 8, 2006

ca:Trànsit de Mercuri de:Merkurtransit es:Tránsito de Mercurio fr:Transit de Mercure ko:?? ???? it:Transito di Mercurio dalla Terra nl:Mercuriusovergang ja:??????? no:Merkurpassasje fi:Merkuriuksen ylikulku zh:????