Archive for the ‘Astronomy’ Category

Navigation

October 25, 2010 - 9:40 pm 326 Comments

Navigation

Navigation is the process of monitoring and controlling the movement of a craft or vehicle from one place to another. The word navigate is derived from the Latin “navigate”, which is the command “sail”.[1] More literally however, the word “Navi” in Sanskrit means ‘boat’ and “Gathi” means ‘direction’.
Celestial navigation, also known as astronavigation, is a position fixing technique that has steadily evolved over several thousand years to help sailors cross featureless oceans without having to rely on estimated calculations, or dead reckoning, to enable them to know their position on the ocean. Celestial navigation uses “sights,” or angular measurements taken between a visible celestial body (the sun, the moon, a planet or a star) and the visible horizon. The angle measured between the sun and the visible horizon is most commonly used. Skilled navigators can additionally use the moon, a planet or one of 57 navigational stars whose coordinates are tabulated in the Nautical Almanac and Air Almanacs.

Celestial navigation is the process whereby angular measurements (sights) taken between celestial bodies in the sky and the visible horizon are used to locate one’s position on the globe, on land as well as at sea. At any given instant of time, any celestial body is located directly over only one specific geographic point, or position on the Earth, whose address is described by latitude and longitude.

Would not have been invented without:

Astronomy
Optics

Astronomy

October 25, 2010 - 7:05 pm 342 Comments

Astronomy

Astronomy (Greek: αστρονομία = άστρον νόμος, astronomia = astron nomos, literally “law of the stars”) is a natural science that deals with the study of celestial objects (such as stars, planets, comets, nebulae, star clusters and galaxies) and phenomena that originate outside the Earth’s atmosphere (such as the cosmic background radiation). It is concerned with the evolution, physics, chemistry, meteorology, and motion of celestial objects, as well as the formation and development of the universe.

Astronomy is one of the oldest sciences. Prehistoric cultures left behind astronomical artifacts such as the Egyptian monuments and Stonehenge, and early civilizations such as the Babylonians, Greeks, Chinese, Indians, and Maya performed methodical observations of the night sky. However, the invention of the telescope was required before astronomy was able to develop into a modern science. Historically, astronomy has included disciplines as diverse as astrometry, celestial navigation, observational astronomy, the making of calendars, and even astrology, but professional astronomy is nowadays often considered to be synonymous with astrophysics.

Early astronomy involved observing the regular patterns of the motions of visible celestial objects, especially the Sun, Moon, stars and naked eye planets. Study of the changing position of the Sun along the horizon or the changing appearances of stars in the course of the year could be used to establish an agricultural or ritual calendar. In some cultures astronomical data was used for astrological prognostication.

Would not have been invented without:

Optics