In astronomy, the naked-eye planets are the five planets of our solar system that can be discerned with the naked eye without much difficulty. Hence, they were the only planets known to the ancients prior to the invention of the telescope. They are Mercury, Venus, Mars, Jupiter, and Saturn, the five planets closest to Earth. The name planet comes from the Greek term πλανήτης, planētēs, meaning "wanderer", as ancient astronomers noted how certain lights moved across the sky in relation to the other stars. They called these objects asteres planetai, or wandering stars. In some cultures, the Sun and Moon have also been counted as planets, to make the seven classical planets.
Mercury and Venus are only visible in twilight hours as their orbits are interior to the Earth's orbit. Venus is the most prominent planet, being the third brightest object in the sky after the Sun and the Moon. Mercury is more difficult to see due to its unwavering proximity to the Sun. Lengthy twilight and an extremely low angle at maximum elongations make optical filters necessary to see Mercury from extreme northerly locations like Scandinavia or Alaska. Mars is at its brightest when it is in opposition to the Earth, which occurs approximately every two years. Jupiter and Saturn are the largest of the five planets, but are farther from the sun, and therefore receive less sunlight. Nonetheless, Jupiter is often the next brightest object in the sky after Venus. Saturn's luminosity is often enhanced by its rings, which reflect light back toward the Earth to varying degrees depending on their inclination to the ecliptic; however, the rings themselves are not visible to the naked eye from the Earth. Uranus and the asteroid Vesta are visible to the naked eye in principle on very clear nights, but unlike the true naked-eye planets they are always less luminous than several thousands of stars, and as such, do not stand out enough for their existences to be noticed without the aid of a telescope.
Every culture has woven them into their myths and legends. They are the basis of the practice of astrology. In English, the planets bear names of gods in Roman mythology, a relic of the ancient belief that planets were gods controlling human destiny. They were sometimes considered to be living beings, and myths were created concerning how they came to be, and what they were supposed to be like, based on their movements in the sky, their physical characteristics, and the supposed influences they have on our planet and its inhabitants.
Astrology was developed when only the naked-eye planets were known. Because they appear to move in cycles about us in the heavens, whereas the "fixed" stars (what we today call the stars) did not, the planets were grouped together with the luminaries and considered to have divinatory significance. At the same time, a distinction was made within this category for the greater importance and brightness of the luminaries (the Sun and the Moon). For more on the significance of naked-eye planets in astrology, see Mercury (astrology), Venus (astrology), Mars (astrology), Jupiter (astrology), and Saturn (astrology).
|Lu-lim||Lu-bat-sag-uš||Saturn||Nirig / Ninip|
The first hour of each day was named after the ruling planet, giving rise to the names and order of the Roman seven-day week. Modern Latin-based cultures, in general, directly inherited the days of the week from the Romans and they were named after the classical planets—for example in Spanish Miércoles = Mercury, in French Mardi = Mars.
The modern English days of the week were inherited from gods of the old Germanic Norse culture—Thursday = Thor, Friday = Frige (Venus). It can be correlated that the Norse gods were attributed to each of the Roman planets and their gods, probably due to Roman influence rather than coincidentally by the naming of the planets.
|Sanskrit Name||English Name||Abbreviation||Image||Yantra||Gender||Guna||Represents||Day|
|Surya (सूर्य)||Sun||Sy or Su||M||Sattva||Soul, king, highly placed persons, father.||Sunday|
|Chandra (चंद्र)||Moon||Ch or Mo||F||Sattva||Mind, queen, mother.||Monday|
|Mangala (मंगल)||Mars||Ma||M||Tamas||energetic action, confidence and ego||Tuesday|
|Budha (बुध)||Mercury||Bu or Me||N||Rajas||Communication and analysis||Wednesday|
|Brihaspati (बृहस्पति)||Jupiter||Gu or Ju||M||Sattva||the great teacher||Thursday|
|Shukra (शुक्र)||Venus||Sk or Ve||F||Rajas||wealth, pleasure and reproduction||Friday|
|Shani (शनि)||Saturn||Sa||N||Tamas||learning the hard way. Career and Longevity||Saturday|
|Rahu (राहु)|| Head of Demon Snake |
Ascending/North Lunar Node
|Ra||F||Tamas||a Asura who does his best to plunge any area of one's life he controls into chaos||none|
|Ketu (केतु)|| Tail of Demon Snake |
Descending/South Lunar Node
|English Name||Associated element||Chinese/Japanese Characters||Japanese romaji||Vietnamese Name|
|Venus||metal/gold||金星||Kinsei||Sao Kim also "Sao Mai" as "morning star" and "Sao Hôm" as "evening star"|
The cycles of the Chinese calendar are linked to the orbit of Jupiter, there being 12 sacred beasts in the Chinese dodecannualar geomantic and astrological cycle, and 12 years in the orbit of Jupiter.