Planetary Science is the scientific study of planets (including Earth), moons, and planetary systems, in particular those of the Solar System. It is a interdisciplinary field that draws on astronomy, chemistry, geology, physics, and biology.
The term “planet” originally referred to any celestial body that appeared to move across the night sky relative to the background stars. The word was coined by ancient Greek astronomers who used it to describe five bright objects that they could see in the sky: Mercury, Venus, Mars, Jupiter, and Saturn. These five objects are now known as the classical planets.
In recent centuries, the definition of “planet” has been expanded to include bodies beyond the Solar System. Some of these are natural satellites (such as our Moon), while others (such as Pluto) have been discovered through telescope surveys of the outer Solar System. In 2006 Pluto was re-designated as a dwarf planet by a decision of the International Astronomical Union.
There are currently eight planets in our Solar System: Mercury, Venus, Earth, Mars, Jupiter, Saturn ,Uranus ,Neptune .An extrasolar planet is a planet located outside our Solar System—that is to say not orbiting our Sun. A large number of extrasolar planets have been discovered in recent years using a variety of detection methods including radial velocity measurements and transits photometry.
The first Extrasolar Planet was discovered in 1992 around a pulsar PSR B1257+12 with 3 confirmed companion planets later found by Alexander Wolszczan and Dale Frail using radio telescopes at Arecibo Observatory and Green Bank Telescope respectively; this discovery was made possible due to advances in technology allowing for very precise timing measurements needed for such tiny effects from distant objects to be observed Fun factoid: one day on Mercury lasts 176 days!
Planetary science covers many different topics including: formation and evolution of planetary systems; characterization of planetary surfaces; planetary atmospheres; meteorites andinterplanetary dust; originand evolutionof lifeon Earthand elsewhere if present ; comparative planetologyof solar system bodies suchas Venusor Marswith Earthgeology ; studiesofthe Sunand its impactonthe solar system(solar windand magnetic fields);dynamicsandformationof galaxiesand star clusters whichmayhost their ownplanetary systems .