Fig (1)
A Solar System Panorama
A composite image of the Solar System, as viewed by NASA’s MESSENGER spacecraft, currently flying to Mercury, the smallest and innermost planet. The image was produced by combining 34 individual images, acquired by MESSENGER, in November 2010. Six planets are visible in the image. They are, from left to right, Venus, Earth, Jupiter, Mars, Mercury and Saturn.
Credit: NASA, Johns Hopkins University Applied Physics Laboratory, Carnegie Institution of Washington

NASA recently published a wonderful image, a family portrait of the Solar System, showing six planets, acquired by the Mercury-bound MESSENGER spacecraft. The planetary panorama is a composite picture, produced by combining 34 individual images, obtained by MESSENGER, in November 2010.

The six planets are, from left to right, Venus, Earth, Jupiter, Mars, Mercury and Saturn. Uranus and Neptune were too distant, currently lying about 3.0 billion km and 4.4 billion km, respectively, from MESSENGER, to be detected by the spacecraft’s imaging device. Their positions, however, are marked on the image. Earth’s Moon and the largest four of Jupiter’s 63 moons are also visible in the image. The Moon is barely discernible, feebly glowing as a pale tiny dot, below and left of Earth.

Fig (2)
An enlarged portion of MESSENGER’s planetary family portrait, showing Earth and the Moon

Fig (3)
This enlarged portion of MESSENGER’s Solar System portrait shows Jupiter and its four major satellites. These Jovian moons have been named after characters of Greek mythology.

Interestingly, on 6 May 2010, MESSENGER was also able to image the Earth-Moon system, from a distance of approximately 180 million km.

MESSENGER, whose name is an acronym from MErcury Surface, Space Environment, GEochemistry and Ranging, was launched into space on 3 August 2004, from Cape Canaveral Air force Station in Florida, aboard a Delta II rocket. It is scheduled to enter orbit around Mercury, on 18 March 2011, to study the planet for a year. By this orbit insertion, MESSENGER will have voyaged through the inner Solar System for nearly seven years, and traversed almost 8 billion km, along a complex path. It will then be Mercury’s first artificial satellite. It is also the second mission to Mercury, since NASA’s Mariner 10 spacecraft performed its third and final flyby of the planet, in 1975. Currently, MESSENGER is moving in an orbit around the Sun, located close to Mercury’s orbit.

Mercury (4,880 km across) is the smallest and innermost planet. It is a rocky, dry world, with a negligible, extremely tenuous atmosphere. Its rugged surface bears a remarkable resemblance to that of the Moon (3,476 km across), but Mercury is 40% larger in diameter, and considerably denser than the Moon. It is one of the four terrestrial (Earth-like) planets. Scientists hope MESSENGER data will improve our understanding of the formation and evolution of both Mercury and Earth.

Intriguingly, MESSENGER’s panorama of the planets is not unique, however. On 14 February 1990, from a distance of approximately 6 billion km, NASA’s Voyager 1 spacecraft took 60 images of the Solar System, producing a mosaic, showing Venus, Earth, Jupiter, Saturn, Uranus and Neptune. Voyager 1 holds the title of the most distant man-made object, as it is located about 17 billion km from Earth.

References

NASA
www.nasa.gov/

MESSENGER Mission Page
http://www.nasa.gov/mission_pages/messenger/main/

Wikipedia

Aymen Mohamed Ibrahem
Senior Astronomy Specialist