Cosmica

London calling

In the limelight

Misheard lyrics

Sail to the moon

Everyday people

Love & happiness

Tangled up in blue

Everlasting nothing

Smells like teen spirit

The cosmos, and understandings of the reasons for its existence and significance, are studied in cosmology — a broad discipline covering scientific, religious or philosophical aspects of the cosmos and its nature.

Eastern and Western thought differed greatly in their understanding of space and the organization of the cosmos. The Chinese saw the Cosmos as empty, infinite, and intertwined with the Earth. Western ideas, based on the ancient Greeks’ understanding of the cosmos, believed in a multi-planar divided cosmos that was finite and filled with air. Europeans viewed the cosmos as a divinely created, spatially finite, bifurcated cosmos, so divided into sublunary and superlunary realms. All objects above the lunar disc were believed to be stable, with heavenly bodies believed to be made out of a refined substance called quintessence. This was understood to be a crystalline, completely transparent substance that held all of the superlunary spheres in perfect order.

Theoretical astrophysicist David N. Spergel has described cosmology as an “historical science” because “when we look out in space, we look back in time” due to the finite nature of the speed of light. Physical cosmology is the branch of physics and astrophysics that deals with the study of the physical origins and evolution of the universe. It includes the study of the nature of the universe on a large scale. In its earliest form, it was what is now known as “celestial mechanics”, the study of the heavens. Greek philosophers Aristarchus of Samos, Aristotle, and Ptolemy proposed different cosmological theories. The geocentric Ptolemaic system was the prevailing theory until the 16th century when Nicolaus Copernicus, and subsequently Johannes Kepler and Galileo Galilei, proposed a heliocentric system. This is one of the most famous examples of epistemological rupture in physical cosmology. Isaac Newton’s Principia Mathematica, published in 1687 was the first description of the law of universal gravitation. It provided a physical mechanism for Kepler’s laws and also allowed the anomalies in previous systems, caused by gravitational interaction between the planets, to be resolved. A fundamental difference between Newton’s cosmology and those preceding it was the Copernican principle — bodies on Earth obey the same physical laws as all celestial bodies. This was a crucial philosophical advance in physical cosmology. Metaphysical cosmology is described as the placing of humans in the universe in relationship to all other entities.

The Principia Mathematica is a three-volume work on the foundations of mathematics written by mathematician–philosophers Alfred North Whitehead and Bertrand Russell and published in 1910, 1912, and 1913. In 1925–1927, it appeared in a second edition with an important Introduction to the Second Edition, an Appendix A that replaced 9 and all-new Appendix B and Appendix C. PM is not to be confused with Russell’s 1903 The Principles of Mathematics. PM was originally conceived as a sequel volume to Russell's 1903 Principles, but as PM states, this became an unworkable suggestion for practical and philosophical reasons: “The present work was originally intended by us to be comprised in a second volume of Principles of Mathematics... But as we advanced, it became increasingly evident that the subject is a very much larger one than we had supposed; moreover on many fundamental questions which had been left obscure and doubtful in the former work, we have now arrived at what we believe to be satisfactory solutions.” PM, according to its introduction, had three aims: One, to analyze to the greatest possible extent the ideas and methods of mathematical logic and to minimize the number of primitive notions, axioms, and inference rules; Two, to precisely express mathematical propositions in symbolic logic using the most convenient notation that precise expression allows; Three, to solve the paradoxes that plagued logic and set theory at the turn of the 20th century, like Russell's paradox. This third aim motivated the adoption of the theory of types in PM. The theory of types adopts grammatical restrictions on formulas that rules out the unrestricted comprehension of classes, properties, and functions. The effect of this is that formulas such as would allow the comprehension of objects like the Russell set turn out to be ill-formed: they violate the grammatical restrictions of the system of PM. Isaac Newton’s Principia Mathematica, published in 1687 was the first description of the law of universal gravitation. The geocentric Ptolemaic system was the prevailing theory until the 16th century when Nicolaus Copernicus, and subsequently Johannes Kepler and Galileo Galilei, proposed a heliocentric system.