Hubble discovers an Expanding Universe

Hubble discovers an Expanding Universe

The Mount Wilson Observatory opened in 1920 with the largest telescope in the world, a huge
100-inch diameter, reflecting mirror. This allowed sufficient resolution to begin identifying
individual stars in galaxies beyond our own Milky Way galaxy. Using Cepheid Variable stars,
whose brightness varies periodically, Edwin Hubble was able to measure the distances to these
galaxies. These are considered standard “candles”, with established intrinsic brightness,
allowing an observed brightness to be converted into a corresponding distance from us. The
distances are immense, beyond what a spaceship traveling at near the speed of light could cover
in a million years. Hubble also learned something about the universe. He was able to determine
how fast each galaxy moved relative to us, by measuring how much the wavelengths of light
were changed according to the Doppler effect. Galaxies moving away from us have their light
stretched out to longer wavelengths, while those moving towards us have their light shrunk to
shorter wavelengths. He found that the universe is expanding at an incredible rate. His famous
law of cosmology was established by 1929, namely, that the further away a galaxy is from us, the
faster it is moving away from us [17]. Einstein, convinced of the results, decided his
cosmological constant was the greatest blunder of his scientific career. The simple and elegant
form of general relativity appeared to be sufficient to describe the universal expansion.
Certain implications of this result were clear. The universal expansion is not like any ordinary
explosion we can observe, where matter is thrust outward in all directions within measurable
space and time. This explosion involved the expansion not only of matter, but of space and time
as well. It makes no sense to ask what lies outside of the expanding universe, since it includes
all of space-time, something we cannot visualize with our 3-dimensional perspective. We can
only use analogies to understand it. One very good analogy is the surface of a 3-dimensional
sphere. Since you only need 2 coordinates (latitude and longitude) to locate any point on its
surface, the surface can be thought of as a 2-dimensional realm. People confined to 2
dimensions would not be able to visualize that their realm is a curved one, but they could
certainly determine that by making some measurements over a large enough area of the surface.
That is exactly why we needed to make measurements over very large distances to determine if
our realm of space is curved, and whether it will continue to expand or slow down and reverse at
some point. In either case, extrapolating backwards in time, the realm of the universe shrinks to
a point, the beginning point where all space and time begins. A beginning then demands a
Beginner, One who is not confined to the universe and the laws that govern it.