EARLY ASTRONOMY

1
EARLY ASTRONOMY
Early cultures identified celestial objects with
gods and spirits. They related these objects (and
their movements) to phenomena such as rain,
drought, seasons, tides, and food.
2
It is generally believed that the first
"professional" astronomers were priests, and that
their understanding of the "heavens" was seen as
"divine". Ancient constructions with astronomical
alienations (such as Stonehenge) probably
fulfilled both astronomical and religious
functions.
3
The study of celestial bodies also served as
Navigational guides.
4
Astrologers studied the relative position of the
Planets and stars to make predictions
concerning a persons destiny.
Astronomy is not to be confused with astrology, a
pseudoscience that attempts to predict a person's
destiny by tracking the paths of astronomical
objects. Although the two fields share a common
origin, they are quite different astronomers
embrace the scientific method, while astrologers
do not.
5
Astronomy, which etymologically means "law of the
stars", (from Greek ast????µ?a ?st??? ??µ??)
is a science involving the observation and
explanation of events occurring outside Earth and
its atmosphere. It studies the origins,
evolution, physical and chemical properties of
objects that can be observed in the sky (and are
outside the earth), as well as the processes
involving them.
6
Astronomy is one of the few sciences where
amateurs can still play an active role,
especially in the discovery and monitoring of
transient phenomena
7
In its earliest days, going back to ancient
Greece and other ancient civilizations, astronomy
consisted largely of astrometry, measuring
positions of stars and planets in the sky
8
Later, the work of Kepler and Newton paved the
way for celestial mechanics, mathematically
predicting the motions of celestial bodies
interacting under gravity, and solar system
objects in particular. Much of the effort in
these two areas, once done largely by hand, is
highly automated nowadays, to the extent that
they are rarely considered as independent
disciplines anymore.
9
Ever since the twentieth century the field of
professional astronomy has tended to split into
observational astronomy and theoretical
astrophysics.
A. Observational astronomy is concerned mostly
with getting data, which involves building and
maintaining instruments and processing the
resulting data this branch is at times referred
to as "astrometry" or simply as "astronomy."
B. Theoretical astrophysics is concerned mainly
with figuring out the observational implications
of different models, and involves working with
computer or analytic models.
10
The fields of study are also categorized in
another two ways by "subject", usually according
to the region of space (e.g. Galactic astronomy)
or "problems addressed" (such as star formation
or cosmology) or by the way used for obtaining
information.
11

• Astrobiology the study of the advent and
  evolution of biological systems in the universe.

12

• Astrometry the study of the position of objects
  in the sky and their changes of position. Defines
  the system of coordinates used and the kinematics
  of objects in our galaxy.

13

• Cosmology the study of the universe as a whole
  and its evolution.

14
Galactic astronomy the study of the structure
and components of our galaxy and of other
galaxies
15

• Extragalactic astronomy the study of objects
  (mainly galaxies) outside our galaxy.

Some topics include Supernovae Quasars Radio
galaxies Groups and clusters of galaxies
16

• Planetary Sciences the study of the planets of
  the solar system.

17
Stellar astronomy the study of the stars
18
Stellar evolution the study of the evolution of
stars from their formation to their end as a
stellar remnant.
19

• Star formation the study of the condition and
  processes that led to the formation of stars in
  the interior of gas clouds, and the process of
  formation itself.

20
Archaeoastronomy (also spelled Archeoastronomy)
is, as the name implies, the combination of
astronomical and archaeological studies.
21
Astrochemistry is the study of the chemicals
found in outer space, usually in molecular gas
clouds, and their formation, interaction and
destruction. As such, it represents an overlap of
the disciplines of astronomy and chemistry.