-Time
Time is a scale and seven basic physical quantities in physics. Comprises one of the length m, time s, mass kg, thermodynamic temperature k (K), current unit a (A), light intensity cd (Candeira) and quantity mol (mole) of a substance, and the symbol is t.
In the definition of physics, time is a scalar With time, we can determine the sequence of events according to the sequence of past-present-future (time point), and we can also measure the duration of events and the length of interval between events (time period). Time is the fourth dimension besides the three dimensions of space.
Time is an abstract concept, which shows the continuity and sequence of material movement and change. The concept of time includes two concepts: time and time period.
Time is a parameter used by human beings to describe the process of material movement or the occurrence of events. The determination of time depends on the law of material circulation that is not affected by the outside world. For example, the cycle of the moon around the earth, the cycle of the earth around the sun, the cycle of the earth's rotation, and the cycle of atomic oscillation. Einstein said that time and space are an illusion of people's cognition.
Time is the quantity formed by the three-dimensional motion (displacement) of all other objects (substances) on the earth (other celestial bodies can also be theoretically) in human senses. As far as the physical theory of 2 1 century is concerned, time is continuous, uninterrupted and has no quantum characteristics.
Some unproven theories, such as quantum gravity theory, string theory and M theory, try to combine relativity with quantum mechanics and predict that time is discontinuous and has quantum characteristics. Some theories speculate that Planck time may be the smallest unit of time.
Broadly speaking, when a point moves relative to a coordinate system, the straight line, line segment or curve formed by its movement is one of the moments when the point is stationary relative to the coordinate system. Each point corresponds to multiple times. Relative to a certain time, the faster the stagnation point starts to move, the slower the time. When the speed is the same as the moving point in this time, time stops. When the speed exceeds this point, it is equivalent to going back to the past.