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A Brief History of Time
"A Brief History of Time" is a popular science work worth reading. It can help readers better understand the nature and mysteries of the universe, and stimulate interest and enthusiasm for science.
Edited at 2024-11-03 21:14:41- Rumi 10 despertares espirituales de alta dimensión
Rumi: 10 dimensiones del despertar espiritual. Cuando dejes de buscarte, encontrarás todo el universo porque lo que estás buscando también te está buscando. Cualquier cosa que haga perseverar todos los días puede abrir una puerta a las profundidades de su espíritu. En silencio, me metí en el reino secreto, y disfruté todo para observar la magia que me rodea y no hice ningún ruido. ¿Por qué te gusta gatear cuando naces con alas? El alma tiene sus propios oídos y puede escuchar cosas que la mente no puede entender. Busque hacia adentro para la respuesta a todo, todo en el universo está en ti. Los amantes no terminan reuniéndose en algún lugar, y no hay separación en este mundo. Una herida es donde la luz entra en tu corazón.
- Fisiopatología - insuficiencia cardíaca
¡La insuficiencia cardíaca crónica no es solo un problema de la velocidad de la frecuencia cardíaca! Es causado por la disminución de la contracción miocárdica y la función diastólica, lo que conduce al gasto cardíaco insuficiente, lo que a su vez causa congestión en la circulación pulmonar y la congestión en la circulación sistémica. Desde causas, inducción a mecanismos de compensación, los procesos fisiopatológicos de insuficiencia cardíaca son complejos y diversos. Al controlar el edema, reducir el frente y la poscarga del corazón, mejorar la función de comodidad cardíaca y prevenir y tratar causas básicas, podemos responder efectivamente a este desafío. Solo al comprender los mecanismos y las manifestaciones clínicas de la insuficiencia cardíaca y el dominio de las estrategias de prevención y tratamiento podemos proteger mejor la salud del corazón.
- Fisiopatología - isquemia - lesión por reperfusión
La lesión por isquemia-reperfusión es un fenómeno que la función celular y los trastornos metabólicos y el daño estructural empeorarán después de que los órganos o tejidos restauren el suministro de sangre. Sus principales mecanismos incluyen una mayor generación de radicales libres, sobrecarga de calcio y el papel de los leucocitos microvasculares y. El corazón y el cerebro son órganos dañados comunes, manifestados como cambios en el metabolismo del miocardio y los cambios ultraestructurales, disminución de la función cardíaca, etc. Las medidas de prevención y control incluyen eliminar los radicales libres, reducir la sobrecarga de calcio, mejorar el metabolismo y controlar las condiciones de reperfusión, como baja sodio, baja temperatura, baja presión, etc. Comprender estos mecanismos puede ayudar a desarrollar opciones de tratamiento efectivas y aliviar las lesiones isquémicas.
A Brief History of Time
- Rumi 10 despertares espirituales de alta dimensión
Rumi: 10 dimensiones del despertar espiritual. Cuando dejes de buscarte, encontrarás todo el universo porque lo que estás buscando también te está buscando. Cualquier cosa que haga perseverar todos los días puede abrir una puerta a las profundidades de su espíritu. En silencio, me metí en el reino secreto, y disfruté todo para observar la magia que me rodea y no hice ningún ruido. ¿Por qué te gusta gatear cuando naces con alas? El alma tiene sus propios oídos y puede escuchar cosas que la mente no puede entender. Busque hacia adentro para la respuesta a todo, todo en el universo está en ti. Los amantes no terminan reuniéndose en algún lugar, y no hay separación en este mundo. Una herida es donde la luz entra en tu corazón.
- Fisiopatología - insuficiencia cardíaca
¡La insuficiencia cardíaca crónica no es solo un problema de la velocidad de la frecuencia cardíaca! Es causado por la disminución de la contracción miocárdica y la función diastólica, lo que conduce al gasto cardíaco insuficiente, lo que a su vez causa congestión en la circulación pulmonar y la congestión en la circulación sistémica. Desde causas, inducción a mecanismos de compensación, los procesos fisiopatológicos de insuficiencia cardíaca son complejos y diversos. Al controlar el edema, reducir el frente y la poscarga del corazón, mejorar la función de comodidad cardíaca y prevenir y tratar causas básicas, podemos responder efectivamente a este desafío. Solo al comprender los mecanismos y las manifestaciones clínicas de la insuficiencia cardíaca y el dominio de las estrategias de prevención y tratamiento podemos proteger mejor la salud del corazón.
- Fisiopatología - isquemia - lesión por reperfusión
La lesión por isquemia-reperfusión es un fenómeno que la función celular y los trastornos metabólicos y el daño estructural empeorarán después de que los órganos o tejidos restauren el suministro de sangre. Sus principales mecanismos incluyen una mayor generación de radicales libres, sobrecarga de calcio y el papel de los leucocitos microvasculares y. El corazón y el cerebro son órganos dañados comunes, manifestados como cambios en el metabolismo del miocardio y los cambios ultraestructurales, disminución de la función cardíaca, etc. Las medidas de prevención y control incluyen eliminar los radicales libres, reducir la sobrecarga de calcio, mejorar el metabolismo y controlar las condiciones de reperfusión, como baja sodio, baja temperatura, baja presión, etc. Comprender estos mecanismos puede ayudar a desarrollar opciones de tratamiento efectivas y aliviar las lesiones isquémicas.
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- Outline
"A Brief History of Time"
Chapter 12: Conclusion
little joke
Starting with Galileo, the work of philosophers and scientists has been distinguished, with philosophers thinking and scientists working and observing. Today's scientific achievements have less and less room for philosophers. The field of philosophy is squeezed by science. After science arrives, philosophers can't understand it.
This book mentions some of the theoretical models that attempt to explain the universe.
Science Trial guides everyone to become a scientist and philosopher, allowing everyone to participate in the discussion of why our universe exists.
Chapter 11: Unification of Physics
String theory combines relativity and quantum mechanics.
Humans live in three dimensions and try to perceive four dimensions. Higher latitudes require greater curvature of space and time, which humans cannot survive or reach.
Two Dimensions Complex living beings (human beings) cannot survive in two dimensions, because if a creature were to have both a food tract and an excretory tract, the creature would disintegrate.
unified theory
Gödel once said that "it is impossible to express calculations in terms of a single family of kilometer systems." Just like the earth we live on cannot describe its surface shape in detail through a two-dimensional plan, at least two maps are needed to cover it, and each map is only effective for a limited area.
Scientists believe there are three possibilities for a unified theory
1. Yes.
2. There is no theoretical sequence (combination), but it can be infinitely close to and accurately describe the entire universe.
3. No.
Hawking believes that excellent physics theories should be understood by everyone.
Physics does not end with a unified theory. The unified theory obtained from the current basis of physics is too complicated, and there is room for simplification, giving humans more ability to create new things. Scientific progress, social development, and the continuation of civilization require every human being to possess a higher level of wisdom.
Chapter 10: Wormholes and Time Travel
time travel
Super-Light Speed If humans can find a reference object and transmit the reference object to observe events faster than light (time compression), we can know what will happen in the future.
Wormhole quantum theory allows space-time to curve, and then creates a black hole to link the curved space-time. As long as we arrive at Proxima Centauri earlier than the time of light, we can travel in time and space.
The paradox of time travel, quantum mechanics believes that there are multiple possible histories in the universe.
Chapter 9: Arrow of Time
Time has three arrows →
The thermodynamic arrow of time is the increase in disorder or entropy in the direction of time.
Psychology's arrow of time, the direction in which we feel time passes, in which we remember the past rather than the future.
Cosmological arrow of time, the direction in which the universe expands, rather than contracts.
Entropy The degree of disorder in the universe never decreases automatically; entropy always increases. Even as the universe expands and contracts, the degree of disorder continues to increase.
Chapter 8: The Origin and Destiny of the Universe
The principle of survival for the strong and the survival of the weak. Scientists try to explain why humans exist, and explore and unify the theory of the beginning of the Big Bang to create a new theory - quantum gravity theory (not yet complete).
Chapter 7: Black holes are not that black
The gravitational force between the two stars causes them to orbit each other. Scientists have discovered that a planet is orbiting another invisible object. There are two possibilities for this invisible object: 1. It is a planet that does not emit light, 2. .is a black hole.
Detect whether it "emits" radiation into the universe. There are particles and antiparticles surrounding a black hole. The particles are attracted to the black hole, and the escape of antiparticles looks like the black hole emitting matter.
The presence of black hole radiation seems to mean that gravitational collapse is not as final and irreversible as we once thought.
General relativity determines that the universe began with the Big Bang at a point with infinite density and infinite compression of space and time; it also predicts that there is also a point with infinite density and infinite compression of space and time inside a black hole. The difference between them is that one is the starting point of expansion and the other is the end point of contraction. In these two singularities, general relativity fails.
Chapter 1: A picture of our universe
Newton's laws of motion
Newton's first law, deduced from Galileo's experiments: The real effect of force is to change the speed of an object, not just to make it move.
Newton's second law describes what happens when an object is acted upon by a force. F (force on the object) = m (mass of the object) × a (acceleration)
Newton's third law states that the action and reaction forces between two interacting objects are equal in magnitude.
Newton's law of gravity.
Hubble - discovered that the universe is expanding.
Einstein's Theory of Relativity.
Quantum theory (quantum theory believes that the universe is full of randomness and uncertainty).
Chapter 2: Space and Time
Kepler discovered that planets move in ellipses.
Newton's laws of motion reveal the fact that the motion states of objects are all relative. There are no absolutely stationary objects and there is no absolutely stationary space.
However, not only was there no way to assign an absolute spatial position to this object, scientists 200 years later even believed that there was no absolute time. In 1887, two scientists (Michelson-Morley experiment) measured the speed of light with season as the only variable, and surprisingly came to the conclusion that the speed of light is constant.
Time Scientists assume that light travels in the ether. The medium of ether is not to prove the propagation path of light, but to explain the movement of light relative to the reference object, thereby calculating the speed of light and stipulating time.
Einstein's theory of relativity
special relativity
The mass of an object is directly proportional to its speed, and the speed of any object cannot exceed the speed of light. (When our speed = the speed of light, we have reached the end of time.)
general relativity
General relativity describes gravity and the large-scale structure of the universe.
The mass or energy of an object causes the surrounding space-time to bend. This bending is manifested as gravity, not a "force". (Gravity is just a manifestation of the curvature of space and time.) For example, if we look across the sun and observe the planet behind it, the actual position of the planet deviates from the position we observe. This is because the gravitational light has also been bent. The motion trajectories of the same planets are actually the result of space curvature.
General relativity requires that the universe must have a beginning. Given the fact that the universe is expanding, the beginning of the universe is a singularity. However, general relativity does not apply in singularities.
four dimensional space
When we describe the position of an object, we can use a set of three coordinates to specify its position, and when we locate an event, something happens at a specific moment and at a specific point in space. At this point we enter the concept of four-dimensional space. ("A Brief History of Time" P35)
Assuming that the event of the death of the sun occurs, using the influence of light as the basis for observation, the light dispersed in this world forms a (three-dimensional) cone in (four-dimensional) space-time. This cone is called the future light cone of the event↓ .
Chapter 3: The Expanding Universe
A prism separates sunlight to obtain the visible spectrum ↓. When Hubble observed the galaxies in the universe, he found that all stars showed a red shift. The red light waves were longer than the blue light waves, which led to the inference that the universe was expanding.
If the universe is constantly expanding, the universe should be very small and hot at the beginning, emitting huge light, which has been transformed into a kind of microwave (which has been detected). If you turn on the TV📺 and adjust it to no video signal, white snowflakes will appear. There are probably 1/20 is the microwave left behind by the early universe.
Chapter 4: Uncertainty Principle
The uncertainty principle is a principle stated by Heisenberg "We can never know the position and velocity of a particle exactly at the same time."
Atoms are composed of nuclei and electrons. When using photons to measure the speed and position of electrons, it will cause interference to the electrons and increase the measurement error. Because it cannot be measured, the "uncertainty principle" is also called the "uncertainty principle."
quantum mechanics
Quantum mechanics does not predict a single definite outcome, but rather describes a set of outcomes and the likelihood of each outcome.
Chapter 5: Elementary Particles and the Forces of Nature
gravitational.
Electromagnetic force is much stronger than gravity. Electrons rotate around the nucleus and are bound by the electromagnetic force.
Strong nuclear force, the nucleus of an atom is composed of protons and neutrons, and the strong nuclear force binds protons and neutrons (and the smaller particles within them) together.
The weak nuclear force causes large atomic nuclei to decay into small atomic nuclei.
Scientists are trying to find a single theory that unifies these four forces. However, the theories describing electromagnetic force, strong nuclear force, and weak nuclear force all rely on quantum mechanics and belong to the research direction of the microscopic world. However, quantum mechanics and relativity still cannot be reconciled.
Chapter Six: Black Hole
Chandrasekhar limit: the maximum mass possible for a stable cold star. A star with a mass exceeding this must collapse into a black hole due to the gravitational attraction and the repulsive force generated by the burning of gas (fuel) (Pauli exclusion principle).
Nuclear fusion occurs in the sun (hydrogen atoms turn into helium atoms). When the nuclear fusion stops and the temperature decreases, the star loses the power to expand, and the gravitational force between the gases causes the star to collapse.
The gravitational pull of a black hole is so strong that even light cannot escape, making the black hole unobservable.