Our View of the Universe

Part of Hall of the Universe.

Our View of the Universe AMNH/D. Finnin

When we look out into space, we also look back into time. Our time-warped view of the observable universe is a blend of the finite speed of light, the age of the universe, and the evolution of the universe.

Age and Size of the Universe

From the observed rate of expansion, astronomers can estimate the age of the universe. For every year, light travels one light-year across space. Hence, the farthest parts of the universe that we can see are as distant in light-years as the universe is old in years. Light from more distant regions has not had time to reach us. This distance marks the limits of the observable universe - our “cosmic horizon.

observing cosmic history
Distant galaxies appear younger because the light we see today left them billions of years ago. Young galaxies in the distant universe provide insight into our Milky Way Galaxy's early evolution.