The content of 10 will adopt a backward narrative form that is easy to understand and conforms to the law of development. From the stage of BIGBANG, we will learn about planets, describe gravity, then start the evolution of life, and finally plunge into quantum physics to meet the most dizzying thing in the world.
10, knocked down by many theories: the big bang theory.
Standard explanation: The Big Bang is a cosmological model that describes the initial conditions for the birth of the universe and its subsequent evolution. Today, it has been widely and accurately supported by scientific research and observation. At present, the general view of the Big Bang is that the universe evolved from the initial state with extremely high density and temperature a finite time ago (according to the best observation results obtained in 20 10, these initial states existed about 65.438+0.33 billion years ago to 65.438+0.39 billion years ago) and reached today's state through continuous expansion.
When anyone wants to try to get in touch with profound scientific theories, it is right to start from the universe, and the Big Bang theory, which explains how the universe has developed so far, is the best choice. The basic structure of this theory is in Edwin? Hubble and George? Lemaistre, Albert? This theory is based on the research of Einstein and many others. To put it bluntly, it is assumed that the universe began with a heavyweight explosion almost 654.38+04 billion years ago. At that time, the universe was confined to a singularity, which contained all the matter in the universe. The initial movement of the universe: continuous outward expansion, is still continuing today.
The Big Bang Theory can get such wide support without Arnold? Penzias and Robert? Wilson's credit. A horn antenna they set up received an indelible noise signal, that is, cosmic electromagnetic radiation, that is, cosmic microwave background radiation. It was the initial big bang that filled the whole universe with this detectable weak radiation, and the corresponding temperature was about 3 K.
9. calculating the age of the universe: Hubble's law
Standard definition: the red shift of light from distant galaxies is proportional to their distance. This law was formulated by Hubble and Milton? After nearly ten years of observation, Humenson formulated Vf=Hc for the first time in 1929. D (departure rate = Hubble constant? The distance from the earth), which is often cited as an important evidence to support the Big Bang today, has become the basis of the theory of cosmic expansion.
This involves one of the above-mentioned people, Edwin? Hubble. This man's contribution to cosmology can be traced back to his deeds: in the roaring and faltering years of the Great Depression in the 1920s, Hubble conducted a breakthrough astronomical research. He not only proved that there are other galaxies besides the Milky Way, but also found that those galaxies are moving away from the Milky Way, and the distance rate in his formula is the speed at which galaxies retreat. Hubble constant refers to the parameter of the expansion rate of the universe, and the distance from the earth is mainly these galaxies. But it is said that Hubble, who is regarded as the founder of galactic astronomy, dislikes the word "galaxy" very much and insists that it is an "extragalactic nebula".
As time goes on, Hubble constant will change, but it doesn't matter much. Importantly, it is this law that helps to quantify the motion of galaxies in the universe and calculate the distance of distant galaxies. The concept that "the universe is made up of many galaxies" and the discovery that the movements of these galaxies can be traced back to the Big Bang all make Hubble's law as famous as the astronomical telescope named after this man.
8. Changing the whole astronomy: Kepler's three laws
Standard interpretation: the laws of planetary motion, three simple laws observed by Kepler in planetary motion.
The first law: every planet moves around the sun along its own elliptical orbit, and the sun is at a focus of the ellipse;
The second law: in the same time, the connecting line between the sun and the moving planet sweeps the same area;
The third law: The square of the period of revolution of the planets around the sun is directly proportional to the cube of the semi-long axis of their elliptical orbits.
Scientists have struggled with religious leaders and their peers for centuries around the orbits of planets, especially whether they are centered on the sun. /kloc-in the 6th century, Copernicus put forward the Heliocentrism, which caused great controversy at that time, thinking that the planet was centered on the sun rather than the earth. What happened after that, Tycho? Blah and others have also discussed it. But it was Johannes who really established a clear scientific foundation for planetary kinematics? Kepler.
Kepler put forward three laws of planetary motion in the early17th century, describing how planets move around the sun. The first law, also known as the elliptic law; The second law, also known as the area law, in other words, explains this law. That is to say, if you track and measure the area formed by the connection between the earth and the sun with the movement of the earth for 30 days in a row, you will find that no matter where the earth is in the orbit and whenever the measurement is started, the result is the same. As for the third law, also known as the law of harmony, it enables us to establish a clear relationship between the orbital period of a planet and its distance from the sun. For example, a planet as close to the sun as Venus has a much shorter orbital period than Neptune. It is these three laws that completely destroyed Ptolemy's complex cosmic system.
7. The cornerstone of most theories: the law of universal gravitation.
Standard explanation: Newton's law of universal gravitation means that any two particles attract each other through the force in the direction of the connecting line. Gravity is directly proportional to their mass product and inversely proportional to the square of their distance, and has nothing to do with the chemical properties or physical states of two objects and intermediate substances. This theory can be expressed by a formula that has been written into today's high school physics textbook: F=G? [(m 1m2)/r2]
Although people take this for granted today, when Isaac? When Newton put forward the theory of universal gravitation more than 300 years ago, it was undoubtedly the most revolutionary event at that time. Newton's theory can be simply expressed as: any two objects, regardless of their respective masses, will exert forces on each other, and the greater the mass, the greater the attraction. In the formula, f refers to the universal gravitation between two objects, and Newton is the unit of measurement; M 1 and m2 respectively represent the mass of two objects; R is the distance between them; G is the gravitational constant.
This is a quite accurate law in many practical situations, but since the development of physics, people have known that Newton's description of gravity is imperfect. However, this law is still one of the most practical concepts in all sciences so far. It is easy to learn and involves a wide range, so that few people paid attention to it in the first period of general relativity. More importantly, the law of universal gravitation gives small human beings the ability to calculate the gravitational force between huge planets, which is especially useful in launching orbiting satellites and drawing lunar exploration routes.
6. Physical science has a basic theorem: Newton's law of motion.
Standard interpretation: Newton's first law is the law of inertia; Newton's second law established the relationship between mass and acceleration; Newton's third law is the law of action and reaction.
Or Newton. Whenever we talk about one of the most outstanding scientists in human history, we have to start with his most famous three laws of mechanics. Because these simple and elegant laws laid the foundation of modern physics.
A brief understanding of the significance of the three laws, the first law let us know that the reason why the rolling ball can move on the floor must be driven by external forces. This external force may be friction with the floor, or a child's kicking. The second law is expressed by the formula F=ma, which also represents a direction vector. When the ball rolls across the floor, it will get a vector pointing in the rolling direction due to the acceleration. Through it, the force on the ball can be calculated. The third law is very simple and well known. It means nothing more than poking your finger at the surface of any object, and they will respond with the same force.
5. The thermodynamic foundation is basically complete: three laws of thermodynamics.
Standard interpretation: the first law of thermodynamics, heat can be transformed into work, and work can also be transformed into heat, that is, the law of energy conservation and transformation; The second law has several expressions. One is that it is impossible to transfer heat from a low-temperature object to a high-temperature object without causing other changes. The third law, when the thermodynamic temperature is zero (that is, T=0), the entropy of all perfect crystals is equal to zero.
British physicist and novelist Charles? Percy. Si Nuo once famously said, "A scientist who doesn't know the second law of thermodynamics is like a scientist who has never read Shakespeare." Si Nuo's speech was intended to criticize the separation and division of "two cultures" between science and humanities, but inadvertently made the second law of thermodynamics "win popularity" among scholars. In fact, Si Nuo's exposition does emphasize and appeal to all humanities scholars to understand its importance.
Thermodynamics is a science that studies the energy movement in a system. The system here can be an engine or a blazing core. Si Nuo summed it up as the following basic rules with his intelligence: You can't win, you can't make ends meet, and you can't quit the game.
How to understand these statements? First, let's look at the so-called "you can't win". Si Nuo means that since matter and energy are conserved, in the process of energy conversion, it is impossible for us to realize the equivalent conversion from one energy form to another without losing some energy. Just like if an engine is to work, it must provide heat energy. Even in a perfect closed space, some heat will inevitably escape to the outside world.
And this leads to the second law, "make ends meet." In view of the infinite increase of entropy, we can't return or keep the same energy state. Because entropy always flows from places with high concentration to places with low concentration. The existence of entropy is also the reason why perpetual motion machine can't appear.
Finally, the third law is "an unavoidable game". The absolute zero here, that is, the theoretically possible lowest temperature, generally refers to zero Kelvin (minus 273.438+05 degrees Celsius or minus 459.67 degrees Fahrenheit). The expression of the third law is that when the system reaches absolute zero, the molecules will stop all motion, that is, in the absence of kinetic energy, the entropy can reach the theoretical minimum. But in the real world, even in the depths of the universe, it is impossible to reach absolute zero. You can only be infinitely close to the so-called end point.
4. Great Wisdom in 200 BC: Archimedes Principle.
Standard explanation: Archimedes principle in physics, that is, Archimedes buoyancy principle, means that the resultant force of an object immersed in a static fluid is equal to the gravity of the fluid displaced by the object, and this resultant force is called buoyancy. The mathematical expression is: F float =G row.
There is a legend about how Archimedes discovered the physical breakthrough of buoyancy principle. When Archimedes took a bath, he saw that the water in the bathtub would rise with the immersion of his body. He was inspired and began to think. When he finally discovered the theory of buoyancy, the greatest philosopher in ancient Greece shouted excitedly, "Found it! Found it! " Streaking naked in the streets of Syracuse.
The ancient discovery of Archimedes, an ancient Greek scholar, has been widely used in all fields of human social production. According to the principle of buoyancy, the force acting on an object partially or completely submerged in liquid is equal to the weight of liquid discharged from the internal volume of the object. This is of great significance for calculating the density of objects, and then designing and building submarines and ocean-going ships.
3. Our own discussion: evolution and natural selection.
Standard definition: evolution, that is, evolution, refers to the change of genetic traits of a population between generations in biology. Natural selection, also known as natural selection, means that the genetic characteristics of organisms have certain advantages or disadvantages in the competition for survival, which leads to the difference between viability and reproductive ability, so that these characteristics can be preserved or eliminated.
Now that we have established some basic conceptual systems about why the universe came from scratch and how physics plays a role in our daily life, we can begin to pay attention to our own form, that is, how we become what we are today.
We know that genes will be copied to the next generation, but gene mutation will change their situation, and this changed new situation may be passed on in the population with species migration.
According to most scientists today, all living things on the earth once had a common ancestor. Later, with the development of time, some of them began to evolve into specific species with distinctive characteristics. With the passage of time, biodiversity has gradually increased and expanded among all organic organisms.
In the most basic sense, mutation mechanisms such as gene mutation have always existed in the process of biological evolution. These detailed changes in each stage will be preserved through the inheritance from generation to generation. Accordingly, biological populations have developed different characteristics, and these characteristics can often help organisms survive better. For example, frogs with brown skin are obviously more suitable for camouflage living in muddy swamp areas than frogs with other colors. This is called natural selection.
Of course, we can also apply the theory of evolution and natural selection to a wider range of organisms. However, Darwin's proposition that "the rich biodiversity on earth comes from natural selection in evolution" in the19th century is undoubtedly still the most basic and groundbreaking.
2. forever changed the way of understanding the universe: general relativity.
Standard explanation: Gravity is described here as a geometric property (curvature) of space-time, and this curvature of space-time is directly related to the energy and momentum tensor of matter and radiation in space-time, and its connection is Einstein's gravitational field equation (a second-order nonlinear partial differential equation group).
For those who have never studied or studied it, the standard interpretation of general relativity is the same as that of not reading it. Because it uses at least four groups of incomprehensible words when explaining the entry.
Its meaning and extension are so extensive that it seems impossible to describe it in a non-paper form. Here, let's take a look at what general relativity, which is called the highest level of modern gravity theory research, is saying. As a more general theory than Newton's gravity, mass is still an important attribute that determines gravity, but it is no longer the only source of gravity.
In Einstein's view, gravity is no longer the force described by Newton, and even the original concept of gravity has disappeared. Because Einstein regarded it as the curvature of spacetime around the object, the "motion of the object under the action of gravity" mentioned earlier comes down to the free motion of the object along the short-distance line in a curved space-time.
If we put the concept of "curved space-time" more clearly, we can imagine the astronauts in the space shuttle flying around the earth. For them, they fly in a straight line in space, but in fact, the space-time around the space shuttle has been bent by the gravity of the earth, which makes the space shuttle an object that can fly forward and rotate around the earth.
John, the chief expert of American relativity research? Wheeler explained that this so-called geometric property of space-time can be summarized as follows: space-time tells matter how to move, and matter tells space-time how to bend. Thus, the bending mode of cosmic starlight influenced by large celestial bodies can be displayed, which lays a theoretical foundation for the study of black holes.
1. Does God roll dice? Heisenberg uncertainty principle
Standard definition: German physicist Heisenberg proposed in 1927 that uncertainty in quantum mechanics means that in a quantum mechanical system, the position of a particle and its momentum (particle mass multiplied by velocity) cannot be determined at the same time.
"measure! In classical theory, this is not a problem to be considered. " The history of quantum physics says so.
That's because in classical physics, you, me, or anyone as an observer have no influence on this objective object waiting to be measured, or the influence is negligible. At that time, even if we didn't understand the truth, it didn't prevent the principle from staying there, waiting for us to learn more slowly.
But now we are about to step into the magic pool of the quantum world, where we as observers will bring some disturbances to the experimental phenomenon, so if we measure the momentum of an electron, the value we get is only relative to you as an observer. In the microscopic world, as far as "probability" is concerned, the so-called God rolls the dice.
Warner in those days? Heisenberg has made a breakthrough in this respect, and people can't get accurate information of two variables of particles at the same time, even with sophisticated instruments. Specifically, you can either know the position of the electron accurately, but you can't know its momentum at the same time, or vice versa. Similar uncertainties exist between energy and time, angular momentum and angle.
Maybe you don't understand the weirdness of this matter. As mentioned earlier, since the quantity in the quantum world is relative, it should be measurable as long as it exists. Since it can't be measured, it doesn't exist. Therefore, it is meaningless to talk about this physical quantity when the means of measurement are uncertain. The momentum of an electron only makes sense when you measure it.
This is more like a philosophical topic. Heisenberg's uncertainty principle was not so much discovered in experiments as discussed by Heisenberg and his teacher Bohr and others. When Bohr discovered that the electron has the properties of both particle and wave (the pillar of quantum physics, wave-particle duality), when we measure the position of the electron, we regard it as a particle with uncertain wavelength; When we want to measure momentum, we regard it as a wave, know the wavelength, but lose its position.
Even if you are extremely confused now, it's still no big deal. Bohr's famous saying is: "Anyone who is not confused about quantum theory must not understand." Similar to the phone bill man also said. So we have nothing to be depressed about. Einstein is in the same situation as us.