Transit of Mercury from Saturn
Encyclopedia
A transit
of Mercury across the Sun as seen from Saturn takes place when the planet Mercury
passes directly between the Sun
and Saturn
, obscuring a small part of the Sun's disc for an observer on Saturn. During a transit, Mercury can be seen from Saturn as a small black disc moving across the face of the Sun.
Naturally, no one has ever seen a transit of Mercury from Saturn, nor is this likely to happen in the foreseeable future. Nevertheless, the next one will take place on December 30, 2011.
A transit could be observed from the surface of one of Saturn's moons rather than from Saturn itself. The times and circumstances of the transits would naturally be slightly different.
The Mercury-Saturn synodic period is 88.694 days. It can be calculated using the formula 1/(1/P-1/Q), where P is the sidereal orbital period
of Mercury (87.968 days) and Q is the orbital period
of Saturn (10746.940 days).
The inclination
of Mercury's orbit with respect to Saturn's ecliptic
is 6.38°, which is less than its value of 7.00° with respect to Earth's ecliptic.
Transits of Mercury from Saturn are empirically observed to occur in clusters, with two such clusters every 30 years or so.
The transit that occurred on March 21, 1894 was particularly interesting, because it happened on the same day as transits of Venus from Saturn
and of Mercury from Venus
. But no two of the transits were simultaneous. Also interesting is the event of December 9, 2056, when Mercury barely misses transiting the Sun, and Venus begins a transit about six hours later.
Note: the image linked to in the following table does not take into account the finite speed of light. The distance of Mercury from Saturn at inferior conjunction is approximately 9.3 AU
or about 80 light-minutes. It will take about 8 hours for Mercury to transit across the Sun, thus the image corresponds fairly closely to what would actually be seen by an observer on Saturn.
Astronomical transit
The term transit or astronomical transit has three meanings in astronomy:* A transit is the astronomical event that occurs when one celestial body appears to move across the face of another celestial body, hiding a small part of it, as seen by an observer at some particular vantage point...
of Mercury across the Sun as seen from Saturn takes place when the planet Mercury
Mercury (planet)
Mercury is the innermost and smallest planet in the Solar System, orbiting the Sun once every 87.969 Earth days. The orbit of Mercury has the highest eccentricity of all the Solar System planets, and it has the smallest axial tilt. It completes three rotations about its axis for every two orbits...
passes directly between the Sun
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...
and Saturn
Saturn
Saturn is the sixth planet from the Sun and the second largest planet in the Solar System, after Jupiter. Saturn is named after the Roman god Saturn, equated to the Greek Cronus , the Babylonian Ninurta and the Hindu Shani. Saturn's astronomical symbol represents the Roman god's sickle.Saturn,...
, obscuring a small part of the Sun's disc for an observer on Saturn. During a transit, Mercury can be seen from Saturn as a small black disc moving across the face of the Sun.
Naturally, no one has ever seen a transit of Mercury from Saturn, nor is this likely to happen in the foreseeable future. Nevertheless, the next one will take place on December 30, 2011.
A transit could be observed from the surface of one of Saturn's moons rather than from Saturn itself. The times and circumstances of the transits would naturally be slightly different.
The Mercury-Saturn synodic period is 88.694 days. It can be calculated using the formula 1/(1/P-1/Q), where P is the sidereal orbital period
Sidereal year
A sidereal year is the time taken by the Earth to orbit the Sun once with respect to the fixed stars. Hence it is also the time taken for the Sun to return to the same position with respect to the fixed stars after apparently travelling once around the ecliptic. It was equal to at noon 1 January...
of Mercury (87.968 days) and Q is the orbital period
Orbital period
The orbital period is the time taken for a given object to make one complete orbit about another object.When mentioned without further qualification in astronomy this refers to the sidereal period of an astronomical object, which is calculated with respect to the stars.There are several kinds of...
of Saturn (10746.940 days).
The inclination
Inclination
Inclination in general is the angle between a reference plane and another plane or axis of direction.-Orbits:The inclination is one of the six orbital parameters describing the shape and orientation of a celestial orbit...
of Mercury's orbit with respect to Saturn's ecliptic
Ecliptic
The ecliptic is the plane of the earth's orbit around the sun. In more accurate terms, it is the intersection of the celestial sphere with the ecliptic plane, which is the geometric plane containing the mean orbit of the Earth around the Sun...
is 6.38°, which is less than its value of 7.00° with respect to Earth's ecliptic.
Transits of Mercury from Saturn are empirically observed to occur in clusters, with two such clusters every 30 years or so.
The transit that occurred on March 21, 1894 was particularly interesting, because it happened on the same day as transits of Venus from Saturn
Transit of Venus from Saturn
A transit of Venus across the Sun as seen from Saturn takes place when the planet Venus passes directly between the Sun and Saturn, obscuring a small part of the Sun's disc for an observer on Saturn...
and of Mercury from Venus
Transit of Mercury from Venus
A transit of Mercury across the Sun as seen from Venus takes place when the planet Mercury passes directly between the Sun and Venus, obscuring a small part of the Sun's disc for an observer on Venus. During a transit, Mercury can be seen from Venus as a small black disc moving across the face of...
. But no two of the transits were simultaneous. Also interesting is the event of December 9, 2056, when Mercury barely misses transiting the Sun, and Venus begins a transit about six hours later.
Note: the image linked to in the following table does not take into account the finite speed of light. The distance of Mercury from Saturn at inferior conjunction is approximately 9.3 AU
Astronomical unit
An astronomical unit is a unit of length equal to about or approximately the mean Earth–Sun distance....
or about 80 light-minutes. It will take about 8 hours for Mercury to transit across the Sun, thus the image corresponds fairly closely to what would actually be seen by an observer on Saturn.