Time?!(3)

Time is quite a physical quantity in our daily life. In physics, a group of things (materials, sources of energy, etc.) that have interactions with each other is called a "system". The interaction could be energetic or material and one of the most important interactions is the movement of the things according to each other.

As we know, time is defined according to movement, and we can claim any system has its own time. For example if we are able to live on Mars, each year would have 687 days. This simple example shows us time is highly dependent on the movement of the planet. Even the systems have contractions with each other and time could be investigated due to each system relatively speaking.