Chapter 1: Cosmic Acceleration/Chapter 9: Origin and Expansion of the Universe

Its interesting to see, looking up at the stars and wondering about how the universe started. I know I’ve asked myself that question once or twice. As we all know, there are many theories that show how the universe began, some more believable than others, but they all have their valid points. This chapter outlines how the scientific community has been able to prove the rapid expansion of the universe and use light to try to understand it.

Light is one of the main focuses within this chapter and as we have learned in physics classes, elements emit their own unique wavelengths of light that translate into different colors on the light spectrum. Scientists have used this understanding, along with advancements in technology, to locate specific elements through out the galaxy and beyond. It is interesting to know that one can look into a telescope and see something millions of kilometers away that isn’t visible to the human eye if it were on the tip of your nose. This Understanding of light along with another previously learned phenomenon, the Doppler effect, not only shows us what is millions of kilometers away, but what its doing. Take the distant galaxy NGC 4860 for example; because the Doppler effect is the result of the difference in wavelengths as something is moving, we can interpret the change in wavelengths (gradually increasing from 656nm) to show us that the galaxy is moving away from us. In relation to this, Edwin Hubble, a renowned scientist, was able to create the equation v = H x d which essentially states that velocity of a galaxy is equal to a constant, H times distance, d. The H constant in this case refers to, you guessed it, another fudged number that represents a key component in determining the velocity at which the galaxy is moving away from the earth. It was given the letter H in honor of Hubble. The d is the distance away from the earth, therefore, according to this equation and Hubble’s work, the farther away a galaxy is from the earth, the faster it is moving. With this we can finally make reference back to what the chapter is about, the expansion of the universe. Because we know that these galaxies are moving away from us we can say, with great certainty, that the universe is expanding at the speed of light. It is an interesting thought and as you look up to the stars you now know that there is an ever lasting and increasing space that will never end. It is also interesting to know that in the time it took you to read this chapter, millions of kilometers have been added the universe. Although a strong theory now, we are not certain that this is the case. Despite this, it is very fascinating to view the universe in such a manor.