Universe

Universe

Think bigger than home, city, or state. Think bigger than country, continent, or planet. Think even bigger than solar system, galaxy, or supercluster. Only one entity encompasses all of these objects, and this is the universe. What's more, the universe is comprised not only of all that humans can directly observe, but also of everything that we cannot see. Along with the most familiar forms of visible matter, elusive entities such as quarks, neutrinos, black holes, and yet-undiscovered forms of dark matter compose the universe.

Simply put, the universe, or cosmos, as it is sometimes called, is everything. It is the entire body of objects and phenomena that may be observed or theoretically postulated. As the late Carl Sagan revealed with the memorable opening line of his bestselling book Cosmos, "The cosmos is all that is or ever was or ever will be."

Scientists continually take on the task of improving our understanding of the universe. They observe the constituents of the universe and the phenomena that pervade its expanse. In so doing, they discover the physical laws that govern the universe. With vast bodies of collected information, scientists then theorize and predict how the universe should behave. Ultimately, subsequent observations serve to test the theories that scientists propose, allowing them to accept those that are consistent, to refine marginal theories, and abandon those that are inconsistent with observation.

The process of bettering human understanding of the universe is cyclic and cumulative. As Isaac Newton suggested, when he offered, "If I have seen farther, it is by standing on the shoulders of giants," each generation relies upon the scientific successes of the former.

The evolution of human understanding of the universe has certainly been long and interesting. The ancient Roman atomists viewed the universe as a body of infinite dimension and complexity. A geocentric universe, with Earth occupying the center, eventually replaced this antique model and reigned supreme through the Middle Ages. Later, it was Nicholas Copernicus who helped us to understand that the Earth is not the center of the universe, while scientists and thinkers like Johannes Kepler, Isaac Newton, and Immanuel Kant paved a way for the understanding that galaxies might exist outside of the Milky Way.

Surprisingly enough, it was not until 1923, when Edwin P. Hubble determined conclusively that the Andromeda Nebula was really a galaxy some 2.5 million light years away, that our notion of the universe expanded to include innumerable galaxies like our own. Moreover, it was also Hubble who widened our perspective to include a universe which is literally expanding. For it was he who discovered in 1929 that all points in the universe are rushing away from one another.

Through the efforts of cumulative scientific investigation, we now know that the universe is governed by four fundamental physical forces: the strong and weak nuclear forces, the gravitational force, and the electrostatic force. We know that Earth is not at the center of the universe; that the Sun is not at the center of the Milky Way galaxy, nor is the Milky Way at the center of the universe; that the universe indeed has no center; that planets revolve around several distant stars; and that there are at least 100 billion galaxies in the universe, each with 100 billion stars. We know that the universe was likely created some 12-15 billion years ago in an unimaginable event known as the big bang and that the universe probably will not end with a big crunch. We have come to know a great deal about the universe in which we live.

With such marked advances and augmentation of our understanding of the universe in the last several thousand years, one can only wonder what will be discovered and learned in the coming millennia. But one thing is certain--the universe is a fascinating place to call home.