Dale said:Yes, this is common in relativity. They are called four-vectors. For example, energy and momentum together form a four-vector where energy is the time component.
I don’t see the difference with this and what you said previouslyDelta² said:I mean i just view Energy as just the 4th component of the energy-momentum 4-vector.
The time component is just the one with the opposite sign in the signature.Delta² said:I expected the time component to be defined in some sort of very special way...
Delta² said:I knew about this but this is not quite what I was thinking.. For example we put the energy together with the momentum as a 4-vector for reasons that suit our computations and equations to be expressed in a compact and elegant form. I mean i just view Energy as just the 4th component of the energy-momentum 4-vector. OR is there some deep conceptual reason that you called the energy the time component of the energy momentum vector?
Huh? Excuse me I don't understand. I guess deep special humour hehe?Dale said:The time component is just the one with the opposite sign in the signature.
PeroK said:You can't transform 3-momentum between frames. To put it crudely, the "energy" in one frame is made up of some of the energy and some of the momentum, as measured in another frame. That's pretty deep.
Yes, that is true too.Delta² said:I was expecting that you would tell me that conservation of the 3-momentum relates to the translational spatial symmetry, while conservation of energy relates to time symmetry, that's another deep reason I can think of
Sorry, I mistakenly assumed since you knew about four-vectors you also knew about signatures. I am not sure now what you know and what you don’t, so please forgive me if I under or over explain.Delta² said:Huh? Excuse me I don't understand. I guess deep special humour hehe?
The concept of time in physics refers to the measurement of the duration of events and the ordering of these events. It is often described as the fourth dimension in the universe and is essential in understanding the behavior and interactions of physical objects.
Yes, time can be measured and quantified using a variety of units such as seconds, minutes, hours, and years. In physics, time is typically measured using a clock or a stopwatch that counts the number of oscillations in a standard unit of time, such as the vibration of a quartz crystal.
According to Einstein's theory of relativity, time is not constant and can vary depending on the speed and gravitational forces of an observer. This phenomenon is known as time dilation and has been experimentally proven through the use of atomic clocks.
In physics, time and space are intertwined and are often referred to as the space-time continuum. This means that time and space are not independent of each other but are rather interconnected and can affect each other's properties.
The arrow of time refers to the one-way direction of time, from the past to the future. This is often associated with the second law of thermodynamics which states that the entropy, or disorder, of a closed system will always increase over time, giving a sense of direction to time's flow.