Friday, 28 June 2013

Top 10 ideas from the history of science.

Cele mai importante 10 idei din istoria ştiinţelor

Once, people believed that the earth is a big flat expanse covered by a solid hemispherical dome - sky - that lead can be turned into gold and that the sun revolves around the earth. A long time ago, and the difference between what we know today and what people think few centuries shows how much things can change in science. But there are some scientific concepts that seem very solid, so solid that it's hard to believe that they could change, moreover, they have decisively influenced science, clearing the ideas, paving paths going research, bringing it closer to human understanding. In this era of rankings, the "charts", here's a provocative question: what would be the most important, the most magnificent 10 scientific ideas of all time?
On the long road traveled by science until today, with tremendous progress and amazing jumps, seems very difficult to gather 10 - just 10 - ideas which to confer importance.
Let's take a "shortcut" to find a Top 10 already made - by someone deeply involved in science and therefore knows what he says - and get this review under the guidance of an expert, the list of 10 concepts scientific it considers the greatest in the history of science millennia.
Nostru7 Guide will be Peter Atkins, professor of chemistry at Oxford University and author of a book published in 2003 and became bestseller entitled Galileo's Finger: The Ten Great Ideas of Science.
I am really 10 exceptional ideas, which, today, most were accustomed to hear such an extent that they no longer seem no big deal - as if everything would be trivialized. But it is just an impression: these 10 ideas are really huge and grand, that convince us, we should try to imagine kinda like without them, such as if no one would have ever found if they would be stated and argued as scientific research would look today without these fundamental ideas.
But here's the top 10 compiled by Professor Peter Atkins, as he was summarized and commented in a recent published Rear Clear Science.
January. Evolution occurs by natural selection mechanism
The power of this concept comes from the fact that he is able to explain both the unity and diversity of the living world, describing how emerging similarities and differences between species of creatures that have emerged from a universal common ancestor. 65% of human genes are also found in unicellular organisms, in fact, all life on Earth are about one third of the genes in common, and this unity in diversity makes sense in light of evolution by natural selection. Or, as the title of an essay published in 1973 by Theodosius Dobzhansky (1900-1975), geneticist and evolutionary biologist: Nothing in biology makes sense except in light of evolution.


One of the most interesting example that illustrates the common heritage of all life, their descent from a common ancestor, is related to the ability of living organisms to synthesize vitamin C. Many organisms can do this: produce vitamin C on their own as the within their metabolism, due to the presence of active genes involved in the final stage of the synthesis of vitamin C.
People are among the few creatures unable to synthesize this vitamin for proper reason that we should eat fruits and vegetables, so they get the vitamin C we need, but we can not produce ourselves. However, we have the above-mentioned gene, but here it is not active, the fact that there is evidence that have a common parentage with other living beings (unit) that show that it is inactive aa diverged in humans (and other some animals) as compared to other species (diversity).
The comparative genetic analysis, one can determine when a mutation occurred that resulted in disabling the gene. The phylogenetic tree of mammals, this mutation occurred in an ancestor that gave rise to all lineages of anthropoid primates, therefore man and chimpanzee, gorilla and Orangutan have all this gene inactive. Other mammals - such as dogs and cats, for example - have retained the ability produce single vitamin C.
And the easiest and most complete explanation of these differences and similarities between species is descended from a common ancestor (unit), a process that took place and some changes in the genome that led to differences in the physiology of organisms (diversity).

2. Information on heredity is coded in DNA
It seems amazing that Gregor Mendel, the "father of genetics", following his famous experiments on peas could talk about the fundamentals of heredity principille without knowing anything about DNA and genes, no doubt a very close insight of a flash of genius made to discern that hereditary characteristics are transmitted through units bearing the hereditary information. He has. called "elements," and today we call genes.
But I could have gone much further than that if, in 1952, scientists would have discovered that DNA is the molecule that carries genetic information and that later in 1953, there have discovered the double helix structure DNA, which was the basis of thousands of experiments later, they went further knowledge in the field of genetics.
In DNA, the genetic information is encoded by means of nitrogenous bases (adenine, cytosine C guanine G thymine T), commonly referred to as "letters", the genes are sequences such nitrogen bases, lined up in a certain sequence, grouped in certain ways, and the basic function of genes from any organism is to provide instructions for protein synthesis in the body.

True, in the decades that followed was also found that, as important as DNA nitrogenous bases of DNA sequence is not sufficient to control what happens in the cells, the emergence of new fields of investigation (one of the most fascinating being the epigenetics, which studies those changes do not affect the DNA sequence of nitrogenous bases, but also involved - how much is not yet known - the hereditary transmission of characters). But without knowing fundamental that DNA is the molecule that contains genetic information, I have come up here and I could go on.


Three. Energy is conserved

   All the energy that exists in the universe has always been here and always will be. Energy is neither created from nothing nor disappears, only turns. Among other things, it can turn mass, where the concept of mass-energy equivalence, on which was made famous Einstein equation E = mc


The two main forms of energy are potential energy (stored energy) and Fore kinetic (movement), most other forms of energy (chemical, electrical, etc.) are just manifestations of potential and kinetic energy, and heat is more of a way The energy transfer.
The fundamental idea that energy can not be created nor destroyed, only transferred and qualify for exchange of one form to another, is based largely technological development reached the contemporary world. I have produced electricity by various means so if I knew that.

April. Entropy: The universe tends toward disorder
Entropy is a measure of disorder - disorder behavior of particles that make up matter - and the second law of thermodynamics states that in any closed system, entropy tends to increase.

  
To counteract this trend, it takes energy input from the outside, but the added energy to decrease entropy in the entropy increases in a different place, and the overall entropy of the universe always increases. (That makes us wonder who will be the ultimate fate of the universe.) However, this knowledge is essential for learners of the cosmos and tries to explain what happened, what is happening and what will happen in the universe.
May. Matter is made of atoms
Air and water, bacteria and humans, computers and heavenly bodies - all are made up of atoms.
For a long time, they were considered the smallest particles in the universe, until scientists came in the privacy of atomic structure, to discover that he has the ingredients of - particles and smaller than him: the nucleus (consisting of protons and neutrons) positively charged, around which electrons rotate, negatively charged. (And protons are in turn made up of even smaller particles - quarks - and scientists actually have not yet agreed when it comes to decide which is the smallest thing in the universe.)
The discovery of the structure of the atom model has allowed, among other things, the creation of the periodic table of elements, the chemistry, chemical without which I could never reach the spectacular today. I have never made synthetic rubber and plastics, synthetic fibers and lots of drugs.

June. Symmetry is a measure of perfection


But symmetry - and its opposite asymmetry without which the concept would be incomplete - are of special interest for astrophysicists and cosmologists. One of the most fascinating facets of the phenomenon is the so-called baryonic asymmetry: the universe is plain hard Amount greater than antimatter, although the Big Bang should have - we think - to give rise to equal amounts of matter and antimatter. What happened to the antimatter? It is one of the great enigmas, still undeciphered, the universe.

July. Classical mechanics is not enough to describe the behavior of particles
If we had stayed in Newton's physics, I did not even have to explain why a piece of iron becomes first red when heated in the fire, and if we continue to run high, will become white. It's a phenomenon that classical physics can not explain it, but quantum mechanics can. Physicist Max Planck came up with the idea that maybe the energy is emitted in quanta called minuscule fraction and the amount of energy that can vary anyway, but discreet. (This is the time to explain what a discrete physical: it has nothing to do with any moral virtue, it means it's a variation on the stairs - quantum energy can take any value, but only those that correspond to whole number of "steps." That is, metaphorically speaking, the difference between a person who would give a slide, being able to stop where she wants to be at a certain height, and one that would descend on scale and can also be placed at a certain height just by choosing a fixed number of steps.)
Today, the energy quanta are called photons Planck expected. Hence, and from other experiments, proved that light, which was considered a wave has, in fact, a dual nature, wave and particle, since particles can occur through discrete photons.
Wave-particle duality and quantum concept for energy underlying quantum mechanics, which we use whenever the laws of classical mechanics do not help. Due to quantum mechanics, we know it's so much about subatomic particles, the structure of the universe - in short, about the world in which we live.
August. Is expanding universe
It is one of the great discoveries of cosmological physics but at the same time, one of the great mysteries of the universe in terms of details.
We know that the Big Bang occurred because we left a "memory" of huge outburst of radiation that accompanied the event: it's about the cosmic background radiation, consisting of microwave (CMB - cosmic microwave background). As the universe expanded, the initial radiation (wave and particle at the same time, as I said above) was also "stretched" - ie, the wavelength increased. That is why, today, this radiation belongs microwave radiation wavelength, higher than the human eye can perceive, reason why we do not see. But it exists and can be detected with proper equipment.
Meanwhile, the universe is expanding, even at speeds increasingly higher. It is not known precisely due to this accelerating expansion of the universe, but it is believed that it was about dark energy, another mysterious thing whose existence we never suspected ever be without this important idea - that the universe is expanding . Based on this idea, scientists have come to put the future of the universe and the fundamental questions: what will happen in the end, to him?

September. Interaction with matter leads to a curved spacetime
First, it's very important idea of ​​space-time or space-time continuum; modern physics adds time as a fourth dimension to the three of space - an important development in cosmological physics because it allowed explaining behavior and influence of large celestial bodies that exert a gravitational force so huge that not only affects the space around them, but also time.
We owe this concept Albert Einstein (general relativity), it's not too easy to understand, but try an analogy: if we imagine the space-time continuum as an elastic fabric in the middle of which sat a huge ball, cloth deforming, would widen, curving in the area where huge ball colossal exercise its effect.


Einstein 2013 then increased its contribution to the development of physics and the theory of special relativity, which describes how time slows down when it is observed, measured on an object that is moving very quickly.

Both theories are taken into account when it comes to certain technologies, such as GPS. If one takes into account the distortion of time due to the speed and gravity, the clocks on Earth and the satellites would operate synchronized and GPS indications of distances would be good for nothing.


10. Mathematics is a limit of reason

Number concept seems simple, but in reality, a number it's very difficult to define, mathematicians have studied the problem, but have failed to reach an agreement in this regard.
 


Infinity also is something that barely fits in the minds of mathematicians. As strange as it sounds, some infinities are bigger than others: the set of rational numbers (those that can be expressed by an ordinary fraction) is infinite, but the set of irrational numbers (which can not be expressed by an ordinary fraction) is it infinite, but higher than the rational numbers.

To complicate matters further, there is a special kind of irrational numbers called transcendental, as the famous number pi, which can be expressed either by a fraction or as a solution of algebraic equations, figures of the sequence to infinity, without repeating after a predictable pattern. And the numbers are so. It follows that the natural numbers (1,2,3 etc..), Which to us seem the most common, are actually very rare!

As scientists deepen math, realize that it is closer to philosophy, fundamental issues such as the existence of infinity and its characteristics seem to take philosophy rather than science. Many mathematical problems unsolved to this day make this discipline a deeply troubling because it reminds us of own limitations and draw a boundary beyond which human reason it is very difficult to pass.

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