Lesson 3 - Astronomy

Astronomy (from the Greek words astron, "star", and nomos, "law") is the scientific study of celestial objects (such as stars, planets, comets, 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.

History
~In early times, astronomy only comprised the observation and predictions of the motions of objects visible to the naked eye. In some locations, such as Stonehenge, early cultures assembled massive artifacts that likely had some astronomical purpose. In addition to their ceremonial uses, these observatories could be employed to determine the seasons, an important factor in knowing when to plant crops, as well as in understanding the length of the year.
Before tools such as the telescope were invented early study of the stars had to be conducted from the only vantage points available, namely tall buildings and high ground using the bare eye.
As civilizations developed, most notably in Mesopotamia, Greece, Egypt, Persia, Maya, India, China, Nubia and the Islamic world, astronomical observatories were assembled, and ideas on the nature of the universe began to be explored. Most of early astronomy actually consisted of mapping the positions of the stars and planets, a science now referred to as astrometry. From these observations, early ideas about the motions of the planets were formed, and the nature of the Sun, Moon and the Earth in the universe were explored philosophically. The Earth was believed to be the center of the universe with the Sun, the Moon and the stars rotating around it. This is known as the geocentric model of the universe.


Galileo's sketches and observations of the Moon.

During the Renaissance, Nicolaus Copernicus proposed a heliocentric model of the solar system. His work was defended, expanded upon, and corrected by Galileo Galilei and Johannes Kepler.

In astronomy, information is mainly received from the detection and analysis of visible light or other regions of the electromagnetic radiation.[19] Observational astronomy may be divided according to the observed region of the electromagnetic spectrum. Some parts of the spectrum can be observed from the Earth's surface, while other parts are only observable from either high altitudes or space.

There are many different fields of Observational astronomy or how we study the universe and they are as follows:
Radio astronomy
Infrared astronomy
Optical astronomy
Ultraviolet astronomy
X-ray astronomy
Gamma-ray astronomy



The Milky Way


The Little Dipper (Top right, upside down) The Big Dipper (The bottem left)

If you have any questions, just ask me or Roise. Hope you learn something new.

<3 Ashleigh