In the article, “The dark side of the of the universe” it talks about how “dark energy,” an unknown form of energy, is pushing galaxies and clusters of galaxies away from each other at a very fast pace. After the Big Bang the universe has been increasing in size in all directions, which is causing galaxies to move away from us as well as each other. The expansion known as, Hubble’s Law, states that the further the galaxy is, the faster it withdraws from us. The steady factor in this linear relationship is called the Hubble constant, which measures the rate of expansion. Not only does Hubble’s Law tell us that the universe is expanding and gives us a way to measure distances, but it also helps in determining the age and size of the universe. The rate at which the universe expands tell us how old it is. This article goes with our 17th objective, “I can explain how astronomer’s know that the universe is expanding and how they determine the age of the universe” because in class we looked at power point slides that included some of the things in the article above. We discussed how the Hubble constant is the value for the expansion rate of the universe. Also, how most galaxies are moving away from us and that distant galaxies are moving the fastest. In class we also did a dot activity where Mr. Morrison chose someone at random in the class and they picked out of the set of dots on the screen which dot would be represented as the Milky Way. Next, Mr. Morrison put another set of dots on the projector over the dots that were already placed and we saw how the dots were expanding from each other. This activity showed the concept of the Hubble Law.
I learned a lot from this conceptual objective. It is amazing how the universe is constantly changing and it will be interesting to see what our galaxy will look like even 5 years from now. Thanks to this 17th objective I now know how the universe is expanding.