astronomy Astronomy is a natural science that studies celestial objects and the phenomena that occur in the cosmos. It uses mathematics, physics, and chemistry in order to explain their origin and their overall evolution. Objects of interest includ ...

, planetary

transit Transit may refer to: Arts and entertainment Film * ''Transit'' (1980 film), a 1980 Israeli film * ''Transit'' (1986 film), a Canadian short film * ''Transit'' (2005 film), a film produced by MTV and Staying-Alive about four people in countrie ...

s and

occultation An occultation is an event that occurs when one object is hidden from the observer by another object that passes between them. The term is often used in astronomy, but can also refer to any situation in which an object in the foreground blocks f ...

s occur when a

planet A planet is a large, Hydrostatic equilibrium, rounded Astronomical object, astronomical body that is generally required to be in orbit around a star, stellar remnant, or brown dwarf, and is not one itself. The Solar System has eight planets b ...

passes in front of another

object Object may refer to: General meanings * Object (philosophy), a thing, being, or concept ** Object (abstract), an object which does not exist at any particular time or place ** Physical object, an identifiable collection of matter * Goal, an a ...

, as seen by an observer. The occulted object may be a distant

star A star is a luminous spheroid of plasma (physics), plasma held together by Self-gravitation, self-gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked eye at night sk ...

, but in rare cases it may be another planet, in which case the event is called a ''mutual planetary occultation'' or ''mutual planetary transit'', depending on the relative

apparent diameter The angular diameter, angular size, apparent diameter, or apparent size is an angular separation (in units of angle) describing how large a sphere or circle appears from a given point of view. In the vision sciences, it is called the '' visual ...

s of the objects.P. Kenneth Seidelmann (ed.)
''Explanatory Supplement to the ''Astronomical Almanac'': A Revision to the Explanatory Supplement to the Astronomical Ephemeris and the American Ephemeris and Nautical Almanac''
(Sausalito A University Science Books, 1992). The word "transit" refers to cases where the nearer object

appears "Appears" is a song recorded by Japanese recording artist Ayumi Hamasaki. It was released by Avex Trax on November 10, 1999, as the sixth single from her second studio album ''Loveppears'' (1999), which was released on the same day. Alongside thi ...

smaller than the more distant object. Cases where the nearer object appears larger and completely hides the more distant object are known as ''occultations''.

Mutual planetary occultations and transits

Mutual occultations or transits of planets are extremely rare. The most recent event occurred on 3 January 1818, and the next will occur on 22 November 2065. Both involve the same two planets:

Venus Venus is the second planet from the Sun. It is often called Earth's "twin" or "sister" planet for having almost the same size and mass, and the closest orbit to Earth's. While both are rocky planets, Venus has an atmosphere much thicker ...

and

Jupiter Jupiter is the fifth planet from the Sun and the List of Solar System objects by size, largest in the Solar System. It is a gas giant with a Jupiter mass, mass more than 2.5 times that of all the other planets in the Solar System combined a ...

Historical observations

An occultation of

Mars Mars is the fourth planet from the Sun. It is also known as the "Red Planet", because of its orange-red appearance. Mars is a desert-like rocky planet with a tenuous carbon dioxide () atmosphere. At the average surface level the atmosph ...

by Venus on 13 October 1590 was observed by the German astronomer

Michael Maestlin Michael Maestlin (; also ''Mästlin'', ''Möstlin'', or ''Moestlin''; 30 September 1550 – 26 October 1631) was a German astronomer and mathematician, best known as the mentor of Johannes Kepler. A student of Philipp Apian, Maestlin is recogniz ...

Heidelberg Heidelberg (; ; ) is the List of cities in Baden-Württemberg by population, fifth-largest city in the States of Germany, German state of Baden-Württemberg, and with a population of about 163,000, of which roughly a quarter consists of studen ...

. The 1737 event (see list below) was observed by

John Bevis John Bevis (10 November 1695 – 6 November 1771) was an English medical doctor, electrical researcher and astronomer. He is best known for discovering the Crab Nebula in 1731. He was educated at Christ Church, Oxford, being awarded his ...

Greenwich Observatory The Royal Observatory, Greenwich (ROG; known as the Old Royal Observatory from 1957 to 1998, when the working Royal Greenwich Observatory, RGO, temporarily moved south from Greenwich to Herstmonceux) is an observatory situated on a hill in G ...

– it is the only detailed account of a mutual planetary occultation. A transit of Mars across Jupiter on 12 September 1170 was observed by the monk Gervase at

Canterbury Canterbury (, ) is a City status in the United Kingdom, city and UNESCO World Heritage Site, in the county of Kent, England; it was a county borough until 1974. It lies on the River Stour, Kent, River Stour. The city has a mild oceanic climat ...

, and by Chinese astronomers.

Future events

The next time a mutual planetary transit or occultation will happen (as seen from Earth) will be on 22 November 2065 at about 12:43

UTC Coordinated Universal Time (UTC) is the primary time standard globally used to regulate clocks and time. It establishes a reference for the current time, forming the basis for civil time and time zones. UTC facilitates international communica ...

, when Venus near superior conjunction (with an

angular diameter The angular diameter, angular size, apparent diameter, or apparent size is an angular separation (in units of angle) describing how large a sphere or circle appears from a given point of view. In the vision sciences, it is called the ''visual an ...

of 10.6") will transit in front of Jupiter (with an angular diameter of 30.9"); however, this will take place only 8° west of the Sun, and will therefore not be visible to the unaided/unprotected eye. Before transiting Jupiter, Venus will occult Jupiter's

moon The Moon is Earth's only natural satellite. It Orbit of the Moon, orbits around Earth at Lunar distance, an average distance of (; about 30 times Earth diameter, Earth's diameter). The Moon rotation, rotates, with a rotation period (lunar ...

Ganymede at around 11:24 UTC as seen from some southernmost parts of Earth.

Parallax Parallax is a displacement or difference in the apparent position of an object viewed along two different sightline, lines of sight and is measured by the angle or half-angle of inclination between those two lines. Due to perspective (graphica ...

will cause actual observed times to vary by a few minutes, depending on the precise location of the observer.

List of mutual planetary occultations and transits

There are only 18 mutual planetary transits and occultations as seen from Earth between 1700 and 2200. There is a very long break of events between 1818 and 2065. *19 September 1702 – Jupiter occults Neptune (pre-discovery) *20 July 1705 – Mercury transits Jupiter *14 July 1708 – Mercury occults Uranus (pre-discovery) Jupiter Venus transit 18180103

*4 October 1708 – Mercury transits Jupiter *28 May 1737 – Venus occults Mercury *29 August 1771 – Venus transits Saturn *21 July 1793 – Mercury occults Uranus *9 December 1808 – Mercury transits Saturn *3 January 1818 – Venus transits Jupiter *22 November 2065 – Venus transits Jupiter *15 July 2067 – Mercury occults Neptune *11 August 2079 – Mercury occults Mars *27 October 2088 – Mercury transits Jupiter *7 April 2094 – Mercury transits Jupiter *21 August 2104 – Venus occults Neptune *14 September 2123 – Venus transits Jupiter *29 July 2126 – Mercury occults Mars *3 December 2133 – Venus occults Mercury

Mutual occultations, transits, and eclipses of the moons of Jupiter and Saturn

Twice during the orbital cycles of Jupiter and

Saturn Saturn is the sixth planet from the Sun and the second largest in the Solar System, after Jupiter. It is a gas giant, with an average radius of about 9 times that of Earth. It has an eighth the average density of Earth, but is over 95 tim ...

, the equatorial (and satellite) planes of those planets are aligned with Earth's orbital plane, resulting in a series of mutual occultations and eclipses between the moons of these giant planets. The terms ''eclipse'', ''occultation'', and ''transit'' are also used to describe these events. A satellite of Jupiter (for example) may be eclipsed (i.e. made dimmer because it moves into Jupiter's shadow), occulted (i.e. hidden from view because Jupiter lies on our line of sight), or may transit (i.e. pass in front of) Jupiter's disk (see also Solar eclipses on Jupiter).

Other planetary occultations

This table is another compilation of occultations and transits of bright stars and planets by solar planets. These events are not visible everywhere the occulting body and the occulted body are above the skyline. Some events are barely visible, because they take place in close proximity to the Sun.

References

{{Portal bar, Astronomy, Stars, Spaceflight, Outer space, Solar System Astronomical events Stellar occultation *