The Nature of the Universe

The universe is described as the largest, oldest, and most expansive entity that exists, encompassing everything from stars to galaxies. It is constantly expanding, which suggests that all matter was once concentrated in a very small space before the Big Bang. This phenomenon of expansion means that as we observe distant stars and galaxies, we are essentially looking back in time, seeing their light that has traveled across vast distances. The concept of light years helps illustrate this, as the time it takes for light to reach us from various celestial objects determines how far back in time we can see.