The universe.  Is it expanding?  Is it shrinking?  Is it a finite space?  If so, what lies beyond the edge of the universe?  If I were to reach my hand past this point, what would I reach into?  These are some of the questions that have always intrigued me, and pushed me to dig deeper into the characteristics of our universe.

Interpretation of the Big Bang

From the very beginning, there have been disputes as to whether the universe is finite or infinite.  For example, Einstein originally argued that the universe was an infinite, yet static universe.  This meant that the universe would continue on forever, but everything – such as our galaxy – would be suspended in space like raisins suspended in an infinite pool of Jell-O.  This was later proved to be false by Edwin Hubble.

Discussed earlier in my post about the Hubble Space Telescope, Edwin Hubble is a famous American astronomer who discovered galaxies other than our own.  While this in itself was a revolutionary discovery, proving there was more to the universe than just our Milky Way, Hubble also detected longer wavelengths of light emitting from these discovered galaxies.  This phenomenon, known as “redshift”, is when light waves appear longer when they are originating from a source that is travelling away from the observer.  By this token, this brought forth the idea that all of the galaxies are flying away from our own galaxy at incredible speeds.

Three different theories of universe expansion

From this idea came three possibilities of expansion: Open Expansion, Flat Expansion, and Closed Expansion.

• Open Expansion – theorizes that the universe will continue to expand infinitely
• Flat Expansion – theorizes that the universe will continue to expand, but will do so at a decreasing rate
• Closed Expansion – theorizes that the universe will eventually stop expanding, and will begin collapsing into itself as time goes on.

The idea of a closed expansion model of the universe is worrying to me, since the concept of the universe collapsing onto itself seems scary.  However, I do not believe there exists an open expansion model because it does not make sense that the universe would be continuously expanding at a faster rate over time.  In my opinion, there simply is not enough evidence to suggest that the universe should keep expanding forever.  Eventually, matter will begin to pull everything back together.

Expanding space, not preexisting space

An important addition to this discovery is that due to the galaxies relative positions to each other, it is clear that they are not expanding into preexisting space.  Instead, space itself seems to be the thing expanding.  So if space is currently expanding, if we rewind time, space should appear to be shrinking.  What would happen if we rewound time until all current matter in the universe was condensed into a small area?  This question began the theory of the Big Bang.

Like most theories about space, there is no certain answer for how the universe is behaving, or what the future holds for the universe.  I am always fascinated by the concept of there being an edge to the universe, and am curious to see where new discoveries take our understanding of the universe and our surroundings.