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The ''Family Portrait'', or sometimes ''Portrait of the Planets'', is an image of the
Six
NASA: Visible Earth
{{Authority control Astronomy image articles Voyager program Bodies of the Solar System Photographs of Earth from outer space 1990 works 1990 in art 1990s photographs February 1990 events
The ''Family Portrait'', or sometimes ''Portrait of the Planets'', is an image of the Solar System
The Solar SystemCapitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Solar S ...
acquired by ''Voyager 1
''Voyager 1'' is a space probe launched by NASA on September 5, 1977, as part of the Voyager program to study the outer Solar System and interstellar space beyond the Sun's heliosphere. Launched 16 days after its twin ''Voyager 2'', ''Voya ...
'' on February 14, 1990 from a distance of approximately 6 billion kilometers from Earth. It features individual frames of six planets and a partial background indicating their relative positions. The picture is a mosaic
A mosaic is a pattern or image made of small regular or irregular pieces of colored stone, glass or ceramic, held in place by plaster/mortar, and covering a surface. Mosaics are often used as floor and wall decoration, and were particularly pop ...
of 60 frames. The frames used to compose the image were the last photographs taken by either Voyager spacecraft (which continued to relay other telemetry afterward). The frames were also the source of the famous ''Pale Blue Dot
''Pale Blue Dot'' is a photograph of planet Earth taken on February 14, 1990, by the ''Voyager 1'' space probe from a record distance of about kilometers ( miles, 40.5 AU), as part of that day's ''Family Portrait'' series of images of the ...
'' image of the Earth
Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...
. Astronomer Carl Sagan
Carl Edward Sagan (; ; November 9, 1934December 20, 1996) was an American astronomer, planetary scientist, cosmologist, astrophysicist, astrobiologist, author, and science communicator. His best known scientific contribution is research on ext ...
, who was part of the Voyager imaging team, campaigned for many years to have the pictures taken.
Description
Six planet
A planet is a large, rounded astronomical body that is neither a star nor its remnant. The best available theory of planet formation is the nebular hypothesis, which posits that an interstellar cloud collapses out of a nebula to create a you ...
s are visible in the mosaic, from left to right: 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 mass more than two and a half times that of all the other planets in the Solar System combined, but ...
, Earth
Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...
, Venus
Venus is the second planet from the Sun. It is sometimes called Earth's "sister" or "twin" planet as it is almost as large and has a similar composition. As an interior planet to Earth, Venus (like Mercury) appears in Earth's sky never fa ...
, 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 nine and a half times that of Earth. It has only one-eighth the average density of Earth; h ...
, Uranus
Uranus is the seventh planet from the Sun. Its name is a reference to the Greek god of the sky, Uranus (mythology), Uranus (Caelus), who, according to Greek mythology, was the great-grandfather of Ares (Mars (mythology), Mars), grandfather ...
, Neptune
Neptune is the eighth planet from the Sun and the farthest known planet in the Solar System. It is the fourth-largest planet in the Solar System by diameter, the third-most-massive planet, and the densest giant planet. It is 17 times ...
. The Sun
The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...
, also a point of light at this distance, is included in the image. Three (then) planets were missed. Mercury
Mercury commonly refers to:
* Mercury (planet), the nearest planet to the Sun
* Mercury (element), a metallic chemical element with the symbol Hg
* Mercury (mythology), a Roman god
Mercury or The Mercury may also refer to:
Companies
* Merc ...
was too close to the Sun to be seen. Mars
Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury (planet), Mercury. In the English language, Mars is named for the Mars (mythology), Roman god of war. Mars is a terr ...
could not be detected by the Voyager cameras due to its position resulting in it only producing a thin crescent from the viewpoint of the spacecraft, and Pluto
Pluto (minor-planet designation: 134340 Pluto) is a dwarf planet in the Kuiper belt, a ring of trans-Neptunian object, bodies beyond the orbit of Neptune. It is the ninth-largest and tenth-most-massive known object to directly orbit the S ...
(which in 1990 was still considered a planet) was not included because its small size and distance from the Sun left it too dim to image. Mars could have been imaged through a clear filter rather than the coloured ones used, but by the time this was realised, the process was too far advanced to make the changes.
The image does not have a unified appearance. The individual frames were acquired using various filters at varying exposures to bring out as much detail as possible in each. For example, the Sun was imaged with the darkest filter and shortest exposure available, to avoid damaging the Imaging Science System vidicon tube
Video camera tubes were devices based on the cathode ray tube that were used in television cameras to capture television images, prior to the introduction of charge-coupled device (CCD) image sensors in the 1980s. Several different types of tubes ...
s. The majority of the frames were acquired in gray scale with the probe's Wide-Angle Camera, while the close-up views of each planet were acquired in color using the Narrow-Angle Camera.
The image was acquired at a distance of approximately from Earth and approximately 32° above the ecliptic
The ecliptic or ecliptic plane is the orbital plane of the Earth around the Sun. From the perspective of an observer on Earth, the Sun's movement around the celestial sphere over the course of a year traces out a path along the ecliptic again ...
plane. Of the two Voyager spacecraft, ''Voyager 1'' was chosen to create the mosaic because its trajectory had taken it above the plane of the Solar System, and unlike ''Voyager 2
''Voyager 2'' is a space probe launched by NASA on August 20, 1977, to study the outer planets and interstellar space beyond the Sun's heliosphere. As a part of the Voyager program, it was launched 16 days before its twin, ''Voyager 1'', on a ...
'', was in a position to view Jupiter free of light disturbances by the Sun's glare. In 2013, a reverse image was taken of ''Voyager 1'', using radio telescopes. ''Voyager 1'' cannot be seen in visible light, but its radio signal is very bright compared to most natural things studied by radio telescopes.
See also
* ''Family Portrait'' (MESSENGER)References
External links
NASA: Visible Earth
{{Authority control Astronomy image articles Voyager program Bodies of the Solar System Photographs of Earth from outer space 1990 works 1990 in art 1990s photographs February 1990 events