Nature
Nature, in the broadest sense, is equivalent to the natural world, physical universe, material world or material universe. "Nature" refers to the phenomena of the physical world, and also to life in general. The term generally does not include manufactured objects and human interaction unless qualified in ways such as, e.g., "human nature" or "the whole of nature". Nature is also generally distinguished from the supernatural. It ranges in scale from the subatomic to the galactic.
Etymology
The word "nature" is derived from the Latin word natura, or "the course of things, natural character."[1] Natura was a Latin translation of the Greek word physis (φύσις), which originally related to the intrinsic characteristics that plants, animals, and other features of the world develop of their own accord. A useful though somewhat erratically presented account of the pre-Socratic use of the concept of φύσις may be found in Naddaf, Gerard The Greek Concept of Nature, SUNY Press, 2006. The word φύσις, while first used in connection with a plant in Homer (as we have seen), occurs very early in Greek philosophy, and in several senses. Generally, these senses match rather well the current senses in which the English word nature is used, as confirmed by Guthrie, W.K.C. Presocratic Tradition from Parmenides to Democritus (volume 2 of his History of Greek Philosophy, Cambridge UP, 1965). This is shown in the first written use of the word φύσις, in connection with a plant. The first known use of physis was by Homer in reference to the intrinsic qualities of a plant: ὣς ἄρα φωνήσας πόρε φάρμακον ἀργεϊφόντης ἐκ γαίης ἐρύσας, καί μοι φύσιν αὐτοῦ ἔδειξε. (So saying, Argeiphontes [=Hermes] gave me the herb, drawing it from the ground, and showed me its nature.) Odyssey 10.302-3 (ed. A.T. Murray). (The word is dealt with thoroughly in Liddell and Scott's Greek Lexicon.) For later but still very early Greek uses of the term, see related below. The concept of nature as a whole, the physical universe, is one of several expansions of the original notion; it began with certain core applications of the word φύσις by pre-Socratic philosophers, and has steadily gained currency ever since. This usage was confirmed during the advent of modern scientific method in the last several centuries. Isaac Newton's Philosophiae Naturalis Principia Mathematica (1687), for example, is translated "Mathematical Principles of Natural Philosophy", and reflects the then-current use of the words "natural philosophy", akin to "systematic study of nature." The etymology of the word "physical" shows its use as a synonym for "natural" in about the mid-15th century: [2]
Within the various uses of the word today, "nature" may refer to the general realm of various types of living plants and animals, and in some cases to the processes associated with inanimate objects; the way that particular types of things exist and change of their own accord, such as the weather and geology of the Earth, and the matter and energy of which all these things are composed. It is often taken to mean the "natural environment" or wilderness; wild animals, rocks, forest, beaches, and in general those things that have not been substantially altered by human intervention, or which persist despite human intervention. This more traditional concept of natural things which can still be found today implies a distinction between the natural and the artificial, with the latter being understood as that which has been brought into being by a human or human-like consciousness or mind.
Earth
Earth (or, "the earth") is the fifth largest planet in the solar system, third in order of distance from the Sun. It is the largest of its planetary system's terrestrial planets and the only place in the universe known to support life.
The most prominent features of the earth's climate are its two large polar regions, two relatively narrow temperate zones, and a wide equatorial tropical to subtropical region. An excellent summary description of global climate can be found at:[3] Precipitation patterns vary widely according to location, ranging from several metres of water per year to less than a millimetre. About 70 percent of the surface is covered by salt-water oceans. The remainder consists of continents and islands, with the vast majority of the inhabited land in the Northern Hemisphere.
Earth has evolved through geological and biological processes that have left traces of the original conditions. The outer surface is divided into several tectonic plates that gradually migrate across the surface over geologic time spans, which at least several times have changed relatively quickly. The interior of the planet remains active, with a thick layer of molten Earth mantle and an iron-filled core that generates a magnetic field.
The atmospheric conditions have been significantly altered from the original conditions by the presence of life forms, [4] which create an ecological balance that stabilizes the surface conditions. Despite the wide regional variations in climate by latitude and other geographic factors, the long-term average global climate is quite stable during interglacial periods,[5] and variations of a degree or two of average global temperature have historically had major effects on the ecological balance, and on the actual geography of the Earth.[6] [7]
Historical perspective
Based on the available evidence, scientists have reconstructed detailed information about the planet's past. Earth is estimated to have formed approximately 4.55 billion years ago out of the solar nebula, along with the Sun and other planets. (The Age of the Earth, ISBN 0-8047-1569-6) The moon formed relatively soon afterwards (roughly 20 million years later, or 4.53 billion years ago).
Initially molten, the outer layer of the planet cooled, resulting in the solid crust. Outgassing and volcanic activity produced the primordial atmosphere. Condensing water vapor, augmented by ice delivered by comets, produced the oceans.[8] The highly energetic chemistry is believed to have produced a self-replicating molecule around 4 billion years ago. [9]
Continents formed, then broke up and re-formed as the surface of Earth reshaped itself over the course of hundreds of millions of years, occasionally combining to make a supercontinent. Roughly 750 million years ago, the earliest known supercontinent Rodinia, began to break apart. The continents later recombined to form Pannotia which broke apart about 540 million years ago, then finally Pangaea, which broke apart about 180 million years ago.[10]
There is significant evidence, still being discussed among scientists, that a severe glacial action during the Neoproterozoic era covered much of the planet in a sheet of ice. This hypothesis has been termed the "Snowball Earth", and it is of particular interest as it precedes the Cambrian explosion in which multicellular life forms began to proliferate about 530-540 million years ago.[11] ISBN 0-521-36615-1
Since the Cambrian explosion there have been five distinctly identifiable mass extinctions. The last mass extinction occurred some 65 million years ago, when a meteorite collision probably triggered the extinction of the non-avian dinosaurs and other large reptiles, but spared small animals such as mammals, which then resembled shrews. Over the past 65 million years, mammalian life diversified. ISBN 0-684-81326-2
Several million years ago, a species of small African ape gained the ability to stand upright.Cite error: Closing </ref> missing for <ref> tag For a brief period in Mars' history, it may have also been capable of forming life. At present though, most of the water remaining on Mars is frozen.
If life exists at all on Mars, it is most likely to be located underground where liquid water can still exist.[1]
Conditions on the other terrestrial planets, Mercury and Venus, appears to be too harsh to support life as we know it. But it has been conjectured that Europa, the fourth-largest moon of Jupiter, may possess a sub-surface ocean of liquid water and could potentially host life.[2]
Recently, the team of Stéphane Udry have discovered a new planet named Gliese 581 c, which is an extrasolar planet orbiting the red dwarf star Gliese 581. Gliese 581 c appears to lay in the habitable zone of space surrounding the star, and therefore could possibly host life as we know it.
See also
Science:
Philosophy:
- Nature (philosophy)
- Mother Nature
- Naturalism (philosophy): any of several philosophical stances, typically those descended from Materialism and Pragmatism that do not distinguish the supernatural from nature. This includes the methodological naturalism of natural science, which makes the methodological assumption that observable events in nature are explained only by natural causes, without assuming either the existence or non-existence of the supernatural.
Media:
- Nature, by Ralph Waldo Emerson
- Nature, a prominent scientific journal
- Natural History, by Pliny the Elder
- Nature (TV series)
Organizations:
External links
- The Essence of Nature Magazine - An online magazine dedicated to nature, animals, and the environment.
- Historical photos of nature
- Some nature related activities for kids
