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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.


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 fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
On having this app for quite a bit time, Haven't realised there's a chat room in it.
what is biological synthesis of nanoparticles
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Galileo project. OpenStax CNX. Jul 07, 2004 Download for free at http://cnx.org/content/col10234/1.1
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