English12_midterm sample2

The universe is measured using astronomical units, light years, parsecs, and the shifting of light waves. Astronomical units are used for the solar system, while light years are used for interstellar distances. Parsecs are used for larger distances, and red/blue shift helps measure distances of galaxies. The distribution of energy includes voids and clusters. Voids are areas with low density, while clusters are groups of galaxies. Superclusters are clusters of clusters. The largest known void is the Bouteus Void, and the largest known supercluster is the King Ghidorah Supercluster. To understand the universe we must first understand how it is measured and how its energy is distributed. Astronomers and scientists alike measure space in astronomical units, light years, parsecs, and by the shifting of light waves. Astronomical units are the most useful measurement for within our own solar system. The distance of one astronomical unit is the distance from the sun to Earth's orbit, or around 93 million miles. Take Neptune for example, it's a staggering distance of 2.8 billion miles away from the sun, but if we put that into astronomical units we get a much more manageable 30 astronomical units away. Light years are used for interstellar distances, or distances between stars. One light year is the distance that a photon of light can travel in one year, which is 6 trillion miles. Take our closest star system, Alpha Centauri for example, which is a distance of 4.3 light years away, rather than 25 trillion miles. Parsecs are used when the number of light years starts to climb into the thousands, or even the millions. One parsec is equal to 3.26 light years. One million light years is referred to as a megaparsec, and these are used for measuring the distances between galaxies. Red and blue shift describes the distortion of light wave frequencies from distant galaxies. Because the universe is expanding, the further away an object is, the faster it is moving away. And the faster a galaxy is moving, the more its light waves shift red. So by measuring its shift in its light wave frequencies, we can determine how far away a galaxy is. If the light is shifted towards the red side of the spectrum, this means the object is moving further away from us. However, if the light is shifted towards the blue side of the spectrum, this means the object is moving towards us. The distribution of energy can be broken down into two categories, voids and clusters. First discovered in 1978 by Stephen Gregory and Laird A. Thompson, voids have a mean density of less than a tenth of the average density of the universe, and are typically hundreds of millions of light years across. When voids reach a diameter of 100 megaparsecs, or around 300 million light years, they're now referred to as supervoids. The single largest discovered void is the Bouteus Void, which is often referred to as the Great Nothing, and for good reason, for having a diameter of 124 megaparsecs. Edwin Hubble was the first to propose the idea that galaxies form in clusters, back in 1936. Clusters contain anywhere from hundreds to thousands of galaxies, and when there is a cluster of these clusters, they are referred to as a supercluster. With the largest of these superclusters being the King Ghidorah Supercluster, this supercluster is three times larger than any other supercluster discovered, having a diameter of 400 megaparsecs, or 1.3 billion light years.