Book contents
- Frontmatter
- Contents
- Foreword
- Preface
- Acknowledgements
- Notes about units
- 1 The Solar System
- 2 The Sun
- 3 The Moon
- 4 Mercury
- 5 Venus
- 6 Earth
- 7 Mars
- 8 Minor members of the Solar System
- 9 Jupiter
- 10 Saturn
- 11 Uranus
- 12 Neptune
- 13 Beyond Neptune: the Kuiper Belt
- 14 Comets
- 15 Meteors
- 16 Meteorites
- 17 Glows and atmospheric effects
- 18 The Stars
- 19 Stellar spectra and evolution
- 20 Extra-solar planets
- 21 Double stars
- 22 Variable stars
- 23 Stellar clusters
- 24 Nebulæ
- 25 The Milky Way Galaxy
- 26 Galaxies
- 27 Evolution of the universe
- 28 The constellations
- 29 The star catalogue
- 30 Telescopes and observatories
- 31 Non-optical astronomy
- 32 The history of astronomy
- 33 Astronomers
- 34 Glossary
- Index
7 - Mars
Published online by Cambridge University Press: 05 June 2012
- Frontmatter
- Contents
- Foreword
- Preface
- Acknowledgements
- Notes about units
- 1 The Solar System
- 2 The Sun
- 3 The Moon
- 4 Mercury
- 5 Venus
- 6 Earth
- 7 Mars
- 8 Minor members of the Solar System
- 9 Jupiter
- 10 Saturn
- 11 Uranus
- 12 Neptune
- 13 Beyond Neptune: the Kuiper Belt
- 14 Comets
- 15 Meteors
- 16 Meteorites
- 17 Glows and atmospheric effects
- 18 The Stars
- 19 Stellar spectra and evolution
- 20 Extra-solar planets
- 21 Double stars
- 22 Variable stars
- 23 Stellar clusters
- 24 Nebulæ
- 25 The Milky Way Galaxy
- 26 Galaxies
- 27 Evolution of the universe
- 28 The constellations
- 29 The star catalogue
- 30 Telescopes and observatories
- 31 Non-optical astronomy
- 32 The history of astronomy
- 33 Astronomers
- 34 Glossary
- Index
Summary
Mars, the fourth planet in order of distance from the Sun, must have been known since very ancient times, since when at its best it can outshine any other planet or star apart from Venus. Its strong red colour led to its being named in honour of the God of War, Ares (Mars): the study of the Martian surface is still officially known as ‘areography’.
Mars was recorded by the ancient Egyptian, Chinese and Assyrian star-gazers, and the Greek philosopher Aristotle (384–22 BC) observed an occultation of Mars by the Moon, although the exact date of the phenomenon is not known. According to Ptolemy, the first precise observation of the position of Mars dates back to 27 January 272 BC, when the planet was close to the star β Scorpii.
Data for Mars are given in Table 7.1. Oppositions occur at a mean interval of 779.9 days, so that, in general, they fall in alternate years (Table 7.2). The closest oppositions occur when Mars is at or near perihelion, as in 2003 when the minimum distance was only 56 000 000 km. The greatest distance between Earth and Mars, with Mars at superior conjunction, may amount to 400 000 000 km. The least favourable oppositions occur with Mars at aphelion, as in 1995 (minimum distance 101 000 000 km).
Mars shows appreciable phases, and at times only 85% of the day side is turned toward us. At opposition, the phase is of course virtually 100%.
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- Information
- Patrick Moore's Data Book of Astronomy , pp. 127 - 155Publisher: Cambridge University PressPrint publication year: 2011