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A brief history of the Ptolemaic System.

Ptolemaic System
In his Dialogue Concerning the Two Chief World Systems, Ptolemaic and Copernican of 1632, Galileo attacked the world system based on the cosmology of Aristotle (384-322 BCE)and the technical astronomy of Ptolemy (ca. 150 CE).

In his books On the Heavens , and Physics , Aristotle put forward his notion of an ordered universe or cosmos. It was governed by the concept ofplace , as opposed to space, and was divided into two distinct parts, the earthly or sublunary region, and the heavens. Theformer was the abode of change and corruption, where things came into being, grew, matured, decayed, and died; the latter was theregion of perfection, where there was no change. In the sublunary region, substances were made up of the four elements,earth, water, air, and fire. Earth was the heaviest, and its natural place was the center of the cosmos; for that reason theEarth was situated in the center of the cosmos. The natural places of water, air, and fire, were concentric spherical shellsaround the sphere of earth. Things were not arranged perfectly, and therefore areas of land protruded above the water. Objectssought the natural place of the element that predominated in them. Thus stones, in which earth predominated, move down to thecenter of the cosmos, and fire moves straight up. Natural motions were, then, radial, either down or up. The four elementsdiffered from each other only in their qualities. Thus, earth was cold and dry while air was warm and moist. Changing one orboth of its qualities, transmuted one element into another. Such transmutations were going on constantly, adding to the constantchange in this sublunary region.

Ptolemy

The heavens, on the other hand, were made up of an entirely different substance, the aether

The traditional English spelling, aether, is used here to distinguish Aristotle's heavenly substance from the modernchemical substance, ether.
or quintessence (fifth element), an immutable substance. Heavenly bodies were part of spherical shells of aether. Thesespherical shells fit tightly around each other, without any spaces between them, in the following order: Moon, Mercury,Venus, Sun, Mars, Jupiter, Saturn, fixed stars. Each spherical shell (hereafter, simply, sphere) had its particular rotation,that accounted for the motion of the heavenly body contained in it. Outside the sphere of the fixed stars, there was the primemover (himself unmoved), who imparted motion from the outside inward. All motions in the cosmos came ultimately from thisprime mover. The natural motions of heavenly bodies and their spheres was perfectly circular, that is, circular and neitherspeeding up nor slowing down.

It is to be noted about this universe that everything had its natural place, a privileged location for bodies with aparticular makeup, and that the laws of nature were not the same in the heavenly and the earthly regions. Further, there were noempty places or vacua anywhere. Finally, it was finite: beyond the sphere of the fixed stars and the prime mover, there wasnothing, not even space. The cosmos encompassed all existence.

Christian Aristotelian Cosmos. From Peter Apian, Cosmographia

Questions & Answers

what is microbiology
Agebe Reply
What is a cell
Odelana Reply
what is cell
Mohammed
how does Neisseria cause meningitis
Nyibol Reply
what is microbiologist
Muhammad Reply
what is errata
Muhammad
is the branch of biology that deals with the study of microorganisms.
Ntefuni Reply
What is microbiology
Mercy Reply
studies of microbes
Louisiaste
when we takee the specimen which lumbar,spin,
Ziyad Reply
How bacteria create energy to survive?
Muhamad Reply
Bacteria doesn't produce energy they are dependent upon their substrate in case of lack of nutrients they are able to make spores which helps them to sustain in harsh environments
_Adnan
But not all bacteria make spores, l mean Eukaryotic cells have Mitochondria which acts as powerhouse for them, since bacteria don't have it, what is the substitution for it?
Muhamad
they make spores
Louisiaste
what is sporadic nd endemic, epidemic
Aminu Reply
the significance of food webs for disease transmission
Abreham
food webs brings about an infection as an individual depends on number of diseased foods or carriers dully.
Mark
explain assimilatory nitrate reduction
Esinniobiwa Reply
Assimilatory nitrate reduction is a process that occurs in some microorganisms, such as bacteria and archaea, in which nitrate (NO3-) is reduced to nitrite (NO2-), and then further reduced to ammonia (NH3).
Elkana
This process is called assimilatory nitrate reduction because the nitrogen that is produced is incorporated in the cells of microorganisms where it can be used in the synthesis of amino acids and other nitrogen products
Elkana
Examples of thermophilic organisms
Shu Reply
Give Examples of thermophilic organisms
Shu
advantages of normal Flora to the host
Micheal Reply
Prevent foreign microbes to the host
Abubakar
they provide healthier benefits to their hosts
ayesha
They are friends to host only when Host immune system is strong and become enemies when the host immune system is weakened . very bad relationship!
Mark
what is cell
faisal Reply
cell is the smallest unit of life
Fauziya
cell is the smallest unit of life
Akanni
ok
Innocent
cell is the structural and functional unit of life
Hasan
is the fundamental units of Life
Musa
what are emergency diseases
Micheal Reply
There are nothing like emergency disease but there are some common medical emergency which can occur simultaneously like Bleeding,heart attack,Breathing difficulties,severe pain heart stock.Hope you will get my point .Have a nice day ❣️
_Adnan
define infection ,prevention and control
Innocent
I think infection prevention and control is the avoidance of all things we do that gives out break of infections and promotion of health practices that promote life
Lubega
Heyy Lubega hussein where are u from?
_Adnan
en français
Adama
which site have a normal flora
ESTHER Reply
Many sites of the body have it Skin Nasal cavity Oral cavity Gastro intestinal tract
Safaa
skin
Asiina
skin,Oral,Nasal,GIt
Sadik
How can Commensal can Bacteria change into pathogen?
Sadik
How can Commensal Bacteria change into pathogen?
Sadik
all
Tesfaye
by fussion
Asiina
what are the advantages of normal Flora to the host
Micheal
what are the ways of control and prevention of nosocomial infection in the hospital
Micheal
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Source:  OpenStax, Solar system. OpenStax CNX. Jun 29, 2007 Download for free at http://cnx.org/content/col10432/1.1
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