The Nature and Expansion of Space

Beginning and End of Space

Space, in the context of the universe, began with the Big Bang approximately 13.8 billion years ago. The Big Bang theory posits that the universe started from an extremely hot, dense state and has been expanding ever since. As for the "end" of space, current understanding suggests that space itself doesn't have an edge or end; it is a continuous and potentially infinite expanse.

How Space is Expanding ?

The expansion of space is described by the metric expansion of space, where the distance between distant objects increases over time. This is not because objects are moving through space, but because space itself is expanding.

Rate of Expansion

The rate at which the universe is expanding is measured by the Hubble Constant (H₀). Current estimates of H₀ are approximately 70 kilometers per second per megaparsec (km/s/Mpc). This means that for every megaparsec (about 3.26 million light-years) of distance, the universe is expanding at an additional 70 kilometers per second.

Amount of Expansion

To quantify how much space is expanding every minute, let's break down the numbers:

1 megaparsec (Mpc) = 3.26 million light-years ≈ 3.09 × 10^19 kilometers.

H₀ ≈ 70 km/s/Mpc.

For every 1 Mpc, space is expanding by 70 km/s. In one minute (60 seconds), this expansion rate would be:

70 km/s × 60 s = 4200 km/min per Mpc

Therefore, every minute, the distance between two points in space separated by 1 Mpc increases by about 4200 kilometers.

Why Space is Expanding ?

The expansion of space is driven by dark energy, a mysterious form of energy that permeates all of space and tends to accelerate the expansion of the universe. While the exact nature of dark energy is still not fully understood, it constitutes about 68% of the total energy density of the current universe, according to observations from the Planck satellite and other measurements.

Statistical Data

Age of Universe: 13.8 billion years

Hubble Constant (H₀): 70 km/s/Mpc

Dark Energy: 68% of the total energy density of the universe

Dark Matter: 27% of the total energy density of the universe

Ordinary Matter: 5% of the total energy density of the universe

Summary

Space began with the Big Bang and has been expanding ever since. The expansion is characterized by the increasing distance between galaxies, driven by dark energy. The rate of expansion, as described by the Hubble Constant, indicates that space expands by approximately 4200 kilometers every minute for every megaparsec of distance. The exact mechanisms of dark energy and the ultimate fate of the universe remain key areas of research in cosmology.