Triple conjunction
Encyclopedia
A triple conjunction is an astronomical
event, where two planet
s or a planet and a star
meet each other three times in a short period either in opposition or at the time of inferior conjunction, if an inferior planet is involved. The visible movement of the planet or the planets in the sky is therefore normally prograde at the first conjunction, retrograde at the second conjunction and again prograde at the third conjunction.
There are three possible cases of triple conjunctions.
Triple conjunctions between Mercury
and Venus
are also possible, if Mercury and Venus are at the same time in inferior conjunction. This event is much rarer and the second conjunction between Mercury and Venus is also invisible.
is in conjunction with the Sun, there is often a triple conjunction between Mars and Mercury or between Mars and Venus. In the events in which Mercury is involved, the second conjunction is invisible because of small elongation from sun; both other events are difficult to see because of the nearness to horizon
and the relatively low brightness of Mars, which is there always near its greatest distance from earth, barely visible.
For a Mars-Venus triple conjunction all three events can almost always be seen, but Mars is dim because of its great distance from the Earth
.
Triple conjunctions between the inferior planets Mercury and Venus and the superior planets Jupiter
, Saturn
, Uranus
, Neptune
, dwarf planet
Pluto
or with star
s take place when these objects are at the same time in conjunction to sun while Mercury or Venus are at inferior conjunction.
Frequently the second conjunction takes place when both bodies are too close to the sun in order to be seen, while the other conjunctions are easily visible, especially if the other body is Jupiter, Saturn or a bright star.
With the dim planets Uranus, Neptune and dwarf planet Pluto the visibility of such an event is difficult, because of the low elongation from Sun.
Triple conjunctions of Mercury and Venus with the exterior planets Jupiter, Saturn, Uranus, Neptune, and dwarf planet Pluto happen relatively frequently (approximately once in 10 years).
During the movement in their inferior conjunction loop Mercury and Venus are always involved in triple conjunctions with some stars. Triple conjunctions with bright stars are as frequent as with exterior planets.
Triple conjunctions between the bright exterior planets are very rare: the last triple conjunctions between Mars and Jupiter occurred in 1789-'90, in 1836-'37 and in 1979-'80. The next events of this kind will be again in 2123 and in 2169-'70.
The last triple conjunctions between Mars and Saturn took place in 1779, 1877 (only in right ascension
) and in 1945-'46. The next triple conjunction between these planets will occur in 2148-'49, in 2185 and in 2187.
For both at triple conjunctions between Mars and Jupiter and for triple conjunctions between Mars and Saturn it is possible that two such events follow at an interval of only 2 years. This last happened for Mars and Jupiter 927 and 929 and will be again in 2742 and 2744. It last happened for Mars and Saturn in 1742-'43 and 1744-'45 and will occur again in 2185 and 2187.
The most historically important triple conjunction was that one between Jupiter and Saturn in 7 BCE-5 BCE, which has been proposed as the explanation for the star of Bethlehem
. Triple conjunctions between Jupiter and Saturn -- so-called Greatest Conjunctions -- last took place in 1682-'83, 1821 (only in right ascension
), 1940-'41 and 1981. It will not occur again until 2238-'39.
There are more frequent triple conjunctions of Jupiter with Uranus or Neptune. They are unspectacular, but offer a good possibility for amateur astronomers to find these dim planets. The next triple conjunction between Jupiter and Uranus will be in 2010-'11 and the next between Jupiter and Neptune will be in 2009.
At each opposition, because of the visible loop movement of the planets, there are triple conjunctions between the planet and some stars. Triple conjunctions between planets and bright stars close to the zodiac
are not so frequent (approximately 2 events in 10 years).
Note that conjunctions in right ascension
and ecliptic longitude need not to take place on the same date. It is possible, that there is a triple conjunction in right ascension, but not in ecliptic longitude and vice versa.
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Astronomy
Astronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...
event, where two planet
Planet
A planet is a celestial body orbiting a star or stellar remnant that is massive enough to be rounded by its own gravity, is not massive enough to cause thermonuclear fusion, and has cleared its neighbouring region of planetesimals.The term planet is ancient, with ties to history, science,...
s or a planet and a star
Star
A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...
meet each other three times in a short period either in opposition or at the time of inferior conjunction, if an inferior planet is involved. The visible movement of the planet or the planets in the sky is therefore normally prograde at the first conjunction, retrograde at the second conjunction and again prograde at the third conjunction.
There are three possible cases of triple conjunctions.
Triple conjunctions between Mercury and Venus
At nearly every inferior conjunction there is a triple conjunction between Mercury and Venus. In most cases the second conjunction is not visible, because both planets have a too small elongation from the Sun.Triple conjunctions between 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...
and Venus
Venus
Venus is the second planet from the Sun, orbiting it every 224.7 Earth days. The planet is named after Venus, the Roman goddess of love and beauty. After the Moon, it is the brightest natural object in the night sky, reaching an apparent magnitude of −4.6, bright enough to cast shadows...
are also possible, if Mercury and Venus are at the same time in inferior conjunction. This event is much rarer and the second conjunction between Mercury and Venus is also invisible.
Triple conjunctions of inferior planets with superior planets or stars
If MarsMars
Mars is the fourth planet from the Sun in the Solar System. The planet is named after the Roman god of war, Mars. It is often described as the "Red Planet", as the iron oxide prevalent on its surface gives it a reddish appearance...
is in conjunction with the Sun, there is often a triple conjunction between Mars and Mercury or between Mars and Venus. In the events in which Mercury is involved, the second conjunction is invisible because of small elongation from sun; both other events are difficult to see because of the nearness to horizon
Horizon
The horizon is the apparent line that separates earth from sky, the line that divides all visible directions into two categories: those that intersect the Earth's surface, and those that do not. At many locations, the true horizon is obscured by trees, buildings, mountains, etc., and the resulting...
and the relatively low brightness of Mars, which is there always near its greatest distance from earth, barely visible.
For a Mars-Venus triple conjunction all three events can almost always be seen, but Mars is dim because of its great distance from the Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
.
Triple conjunctions between the inferior planets Mercury and Venus and the superior planets Jupiter
Jupiter
Jupiter is the fifth planet from the Sun and the largest planet within the Solar System. It is a gas giant with mass one-thousandth that of the Sun but is two and a half times the mass of all the other planets in our Solar System combined. Jupiter is classified as a gas giant along with Saturn,...
, 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,...
, Uranus
Uranus
Uranus is the seventh planet from the Sun. It has the third-largest planetary radius and fourth-largest planetary mass in the Solar System. It is named after the ancient Greek deity of the sky Uranus , the father of Cronus and grandfather of Zeus...
, Neptune
Neptune
Neptune is the eighth and farthest planet from the Sun in the Solar System. Named for the Roman god of the sea, it is the fourth-largest planet by diameter and the third largest by mass. Neptune is 17 times the mass of Earth and is slightly more massive than its near-twin Uranus, which is 15 times...
, dwarf planet
Dwarf planet
A dwarf planet, as defined by the International Astronomical Union , is a celestial body orbiting the Sun that is massive enough to be spherical as a result of its own gravity but has not cleared its neighboring region of planetesimals and is not a satellite...
Pluto
Pluto
Pluto, formal designation 134340 Pluto, is the second-most-massive known dwarf planet in the Solar System and the tenth-most-massive body observed directly orbiting the Sun...
or with star
Star
A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...
s take place when these objects are at the same time in conjunction to sun while Mercury or Venus are at inferior conjunction.
Frequently the second conjunction takes place when both bodies are too close to the sun in order to be seen, while the other conjunctions are easily visible, especially if the other body is Jupiter, Saturn or a bright star.
With the dim planets Uranus, Neptune and dwarf planet Pluto the visibility of such an event is difficult, because of the low elongation from Sun.
Triple conjunctions of Mercury and Venus with the exterior planets Jupiter, Saturn, Uranus, Neptune, and dwarf planet Pluto happen relatively frequently (approximately once in 10 years).
During the movement in their inferior conjunction loop Mercury and Venus are always involved in triple conjunctions with some stars. Triple conjunctions with bright stars are as frequent as with exterior planets.
Triple conjunctions between two exterior planets
These are the most interesting triple conjunctions, because all three conjunctions can be seen very easily, because of the great elongation of the planets or stars involved. Triple conjunctions between exterior planets or an exterior planet and a star can only occur when these objects are nearly simultaneously in opposition.Triple conjunctions between the bright exterior planets are very rare: the last triple conjunctions between Mars and Jupiter occurred in 1789-'90, in 1836-'37 and in 1979-'80. The next events of this kind will be again in 2123 and in 2169-'70.
The last triple conjunctions between Mars and Saturn took place in 1779, 1877 (only in right ascension
Right ascension
Right ascension is the astronomical term for one of the two coordinates of a point on the celestial sphere when using the equatorial coordinate system. The other coordinate is the declination.-Explanation:...
) and in 1945-'46. The next triple conjunction between these planets will occur in 2148-'49, in 2185 and in 2187.
For both at triple conjunctions between Mars and Jupiter and for triple conjunctions between Mars and Saturn it is possible that two such events follow at an interval of only 2 years. This last happened for Mars and Jupiter 927 and 929 and will be again in 2742 and 2744. It last happened for Mars and Saturn in 1742-'43 and 1744-'45 and will occur again in 2185 and 2187.
The most historically important triple conjunction was that one between Jupiter and Saturn in 7 BCE-5 BCE, which has been proposed as the explanation for the star of Bethlehem
Star of Bethlehem
In Christian tradition, the Star of Bethlehem, also called the Christmas Star, revealed the birth of Jesus to the magi, or "wise men", and later led them to Bethlehem. The star appears in the nativity story of the Gospel of Matthew, where magi "from the east" are inspired by the star to travel to...
. Triple conjunctions between Jupiter and Saturn -- so-called Greatest Conjunctions -- last took place in 1682-'83, 1821 (only in right ascension
Right ascension
Right ascension is the astronomical term for one of the two coordinates of a point on the celestial sphere when using the equatorial coordinate system. The other coordinate is the declination.-Explanation:...
), 1940-'41 and 1981. It will not occur again until 2238-'39.
There are more frequent triple conjunctions of Jupiter with Uranus or Neptune. They are unspectacular, but offer a good possibility for amateur astronomers to find these dim planets. The next triple conjunction between Jupiter and Uranus will be in 2010-'11 and the next between Jupiter and Neptune will be in 2009.
At each opposition, because of the visible loop movement of the planets, there are triple conjunctions between the planet and some stars. Triple conjunctions between planets and bright stars close to the zodiac
Zodiac
In astronomy, the zodiac is a circle of twelve 30° divisions of celestial longitude which are centred upon the ecliptic: the apparent path of the Sun across the celestial sphere over the course of the year...
are not so frequent (approximately 2 events in 10 years).
Triple conjunction of the planets Mars, Jupiter, Saturn, Uranus and Neptune in right ascension between 1800 and 2100
| Year | Involved planets | 1st Conjunction | 2nd Conjunction | 3rd Conjunction |
|---|---|---|---|---|
| 1821 | Uranus-Neptune | March 17 | May 7 | December 2 |
| 1821 | Jupiter-Saturn | June 25 | November 23 | December 23 |
| 1836/37 | Mars-Jupiter | November 14, 1836 | March 5, 1837 | March 23, 1837 |
| 1843 | Jupiter-Neptune | April 9 | September 15 | November 5 |
| 1845 | Mars-Neptune | June 18 | September 2 | October 3 |
| 1846 | Saturn-Neptune | March 31 | September 14 | December 3 |
| 1851/52 | Saturn-Uranus | July 15, 1851 | October 4, 1851 | March 4, 1852 |
| 1877 | Mars-Saturn | July 27 | August 26 | November 4 |
| 1888 | Mars-Uranus | January 9 | May 5 | June 7 |
| 1896/97 | Mars-Neptune | September 24, 1896 | December 12, 1896 | February 19, 1897 |
| 1896/97 | Saturn-Uranus | December 28, 1896 | June 19, 1897 | August 26, 1897 |
| 1907 | Mars-Uranus | May 2 | July 19 | August 24 |
| 1919/20 | Jupiter-Neptune | September 23, 1919 | March 13, 1920 | April 20, 1920 |
| 1927/28 | Jupiter-Uranus | July 9, 1927 | August 19, 1927 | January 23, 1928 |
| 1932/33 | Mars-Neptune | December 5, 1932 | March 11, 1933 | May 16, 1933 |
| 1940/41 | Jupiter-Saturn | August 15, 1940 | October 12, 1940 | February 20, 1941 |
| 1943/44 | Mars-Uranus | September 9, 1943 | December 26, 1943 | January 20, 1944 |
| 1945/46 | Mars-Saturn | October 26, 1945 | January 22, 1946 | March 19, 1946 |
| 1952/53 | Saturn-Neptune | November 18, 1952 | May 31, 1953 | July 11, 1953 |
| 1954/55 | Jupiter-Uranus | October 8, 1954 | January 6, 1955 | May 10, 1955 |
| 1964/65 | Mars-Uranus | December 5, 1964 | April 3, 1965 | May 6, 1965 |
| 1968/69 | Jupiter-Uranus | December 9, 1968 | March 15, 1969 | July 18, 1969 |
| 1971 | Jupiter-Neptune | February 2 | May 20 | September 18 |
| 1979/80 | Mars-Jupiter | December 13, 1979 | March 2, 1980 | May 4, 1980 |
| 1981 | Jupiter-Saturn | January 14 | February 19 | July 30 |
| 1983 | Jupiter-Uranus | February 17 | May 16 | September 24 |
| 1988 | Saturn-Uranus | February 13 | June 27 | October 18 |
| 1989 | Saturn-Neptune | March 3 | June 24 | November 12 |
| 1993 | Uranus-Neptune | January 26 | September 17 | September 28 |
| 2009 | Jupiter-Neptune | May 25 | July 13 | December 20 |
| 2010/11 | Jupiter-Uranus | June 6, 2010 | September 22, 2010 | January 2, 2011 |
| 2025/26 | Saturn-Neptune | June 29, 2025 | August 6, 2025 | February 16, 2026 |
| 2037/38 | Jupiter-Uranus | September 8, 2037 | February 19, 2038 | March 30, 2038 |
| 2041/42 | Mars-Uranus | November 2, 2041 | March 16, 2042 | March 18, 2042 |
| 2047/48 | Jupiter-Neptune | July 24, 2047 | November 15, 2047 | February 26, 2048 |
| 2063 | Mars-Uranus | February 23 | May 27 | July 17 |
| 2066 | Jupiter-Uranus | January 19 | June 27 | August 18 |
| 2071/72 | Mars-Neptune | October 8, 2071 | February 5, 2072 | February 29, 2072 |
| 2079 | Saturn-Uranus | February 28 | August 29 | October 23 |
| 2085/86 | Jupiter-Neptune | October 30, 2085 | January 13, 2086 | June 8, 2086 |
| 2088/89 | Mars-Neptune | December 14, 2088 | January 4, 2089 | May 13, 2089 |
| 2093 | Jupiter-Uranus | May 16 | October 27 | November 30 |
Triple conjunction of the planets Mars, Jupiter, Saturn, Uranus and Neptune in ecliptic longitude between 1800 and 2100
| Year | Involved planets | 1st Conjunction | 2nd Conjunction | 3rd Conjunction |
|---|---|---|---|---|
| 1821 | Uranus-Neptune | March 22 | May 3 | December 3 |
| 1836/37 | Mars-Jupiter | November 15, 1836 | February 28, 1837 | March 29, 1837 |
| 1843 | Jupiter-Neptune | April 9 | September 12 | November 8 |
| 1845 | Mars-Neptune | June 21 | August 22 | October 8 |
| 1846 | Saturn-Neptune | April 4 | September 5 | December 11 |
| 1888 | Mars-Uranus | January 11 | May 4 | June 5 |
| 1896/97 | Mars-Neptune | September 24, 1896 | December 13, 1896 | February 18, 1897 |
| 1897 | Saturn-Uranus | January 6 | June 1 | September 9 |
| 1907 | Mars-Uranus | May 2 | July 17 | August 26 |
| 1919/20 | Jupiter-Neptune | September 24, 1919 | March 8, 1920 | April 24, 1920 |
| 1927/28 | Jupiter-Uranus | July 15, 1927 | August 11, 1927 | January 25, 1928 |
| 1932/33 | Mars-Neptune | December 6, 1932 | March 7, 1933 | May 17, 1933 |
| 1940/41 | Jupiter-Saturn | August 8, 1940 | October 20, 1940 | February 15, 1941 |
| 1943/44 | Mars-Uranus | September 9, 1943 | December 30, 1943 | January 16, 1944 |
| 1945/46 | Mars-Saturn | October 27, 1945 | January 20, 1946 | March 20, 1946 |
| 1952/53 | Saturn-Neptune | November 21, 1952 | May 17, 1953 | July 22, 1953 |
| 1954/55 | Jupiter-Uranus | October 7, 1954 | January 7, 1955 | May 10, 1955 |
| 1964/65 | Mars-Uranus | December 6, 1964 | March 29, 1965 | May 8, 1965 |
| 1968/69 | Jupiter-Uranus | December 11, 1968 | March 11, 1969 | July 20, 1969 |
| 1971 | Jupiter-Neptune | February 1 | May 22 | September 16 |
| 1979/80 | Mars-Jupiter | December 16, 1979 | February 27, 1980 | May 5, 1980 |
| 1980/81 | Jupiter-Saturn | December 31, 1980 | March 4, 1981 | July 24, 1981 |
| 1983 | Jupiter-Uranus | February 18 | May 14 | September 25 |
| 1988 | Saturn-Uranus | February 13 | June 26 | October 18 |
| 1989 | Saturn-Neptune | March 3 | June 24 | November 13 |
| 1993 | Uranus-Neptune | February 2 | August 19 | October 25 |
| 2009 | Jupiter-Neptune | May 27 | July 10 | December 21 |
| 2010/11 | Jupiter-Uranus | June 8, 2010 | September 19, 2010 | January 4, 2011 |
| 2037/38 | Jupiter-Uranus | September 8, 2037 | February 19, 2038 | March 30, 2038 |
| 2041/42 | Mars-Uranus | November 2, 2041 | March 5, 2042 | March 28, 2042 |
| 2047/48 | Jupiter-Neptune | July 22, 2047 | November 16, 2047 | February 24, 2048 |
| 2063 | Mars-Uranus | February 24 | May 28 | July 15 |
| 2066 | Jupiter-Uranus | January 20 | June 24 | August 21 |
| 2071/72 | Mars-Neptune | October 8, 2071 | February 2, 2072 | March 3, 2072 |
| 2079 | Saturn-Uranus | February 26 | August 31 | October 21 |
| 2085/86 | Jupiter-Neptune | November 1, 2085 | January 10, 2086 | June 10, 2086 |
| 2093 | Jupiter-Uranus | May 17 | October 21 | December 5 |
Note that conjunctions in right ascension
Right ascension
Right ascension is the astronomical term for one of the two coordinates of a point on the celestial sphere when using the equatorial coordinate system. The other coordinate is the declination.-Explanation:...
and ecliptic longitude need not to take place on the same date. It is possible, that there is a triple conjunction in right ascension, but not in ecliptic longitude and vice versa.
See also
- Great conjunctionGreat conjunctionA Great Conjunction is a conjunction of the planets Jupiter and Saturn. The last Great Conjunction took place on May 31, 2000, while the next one will be in late December 2020. Great Conjunctions take place regularly, every 18–20 years, as a result of the combined ~12-year orbital period of Jupiter...
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- This text is a translation of the German Wikipedia article :de:Dreifache Konjunktion. Please update as needed.