The Friedmann-Robertson-Walker (FRW) metric is a mathematical model used in cosmology to describe the expanding universe. It is based on the general theory of relativity and provides a way to calculate the distances between objects in the universe.
The proper distance between two objects in the universe is calculated using the FRW metric by taking into account the expansion of the universe. This means that the distance between two objects will increase over time as the universe continues to expand.
The proper distance is an important concept in cosmology as it allows us to measure the distances between objects in the expanding universe. This is crucial for understanding the evolution and structure of the universe.
Yes, the FRW metric takes into account the curvature of space, which is affected by the distribution of matter and energy in the universe. This curvature can affect the calculation of proper distance between objects.
The expansion of the universe causes proper distance between objects to increase over time. This is because as the universe expands, the space between objects also expands, making it appear as though the objects are moving farther away from each other.