As I like to say, an adventure a day keeps the boredom away. Today was a great day right from the beginning. Blessed with a full 8 hours of sleep because of the cereal stash in our room, I felt ready to go from the moment I woke up. The cereal wasn’t quite filling enough however, so I grabbed a bagel from the food cart outside of our classroom and took my seat. While much of the last week’s work has been on fundamentals such as mechanics and basic optics, today was time for our introduction to modern physics. After a brief lecture, Bill introduced us to Dr. Mark Trodden so that he could introduce us to some modern physics. Assisted by his slight British accent and charismatic oratory, Mark was very easy to listen to and understand. Mark began his lecture by introducing his field of study-particle cosmology-. He soon began to discuss one of the most important particles/waves in his field, the photon of light. We sped through some introductory stuff, the majority of which I already knew, about the Doppler Effect. The Doppler Effect takes place when there is a moving source or receiver of some kind of waves. For example, a car that is driving along the street and passes by a person standing on the sidewalk exhibits the Doppler Effect. What happens is that as the source and observer become closer while the source is emitting waves, the sources waves continually get scrunched up because each successive wave emitted is closer to the source than the last one. By definition, closer waves meant that the waves that the observer observes are at a higher frequency than they were emitted. Based on the shifts in the spectrum of emitted light from objects such as stars, astronomers can tell how quickly distant objects are moving.
The next topic that Mark spoke about was one that everyone used to think they understood perfectly- gravity-. For hundreds of years, Newton’s Law of Gravitation had worked great at describing every application that was thrown at it. Soon enough, people realized that it didn’t accurately describe the orbit of Mercury. During Einstein’s amazing burst of science, he came up with the Theory of General Relativity which envisions gravity as bending space and time.
To continue his discussion, Mark began to talk about an area of physics that he dedicates a huge amount of his time to, the Big Bang. He discussed how immediately after the Big Bang atoms would form for fractions of a second and then get hit by a massive amount of light that would break them apart. A few seconds after the Big Bang, protons had enough energy to collide and make nuclei without being torn apart by light. While this phase lasted less than a minute after the Big Bang it was the only window where atomic nuclei were formed. Scientists made careful theories to predict the abundance of light elements in the universe due to the Big Bang. In one of the greatest documented successes of science, the model fit the actual data almost perfectly. This occurrence was a great success for science because of how well the model and actual data lined up.
Finally, Mark introduced several questions that he is researching because particle cosmology currently fails to explain them.
Why is there more matter than antimatter?
Why didn’t the universe begin in a higher state of entropy?
Does dark energy really exist, or does General Relativity break down on universal scales?
I found Mark’s lecture very informative and above all, it made me want to learn more about our universe. In the afternoon we had a lab to learn about things in nature that display exponential properties. My group decided to try the lab where you try to find if object’s cool and heat up at exponential rates. Using a thermometer linked to Logger Pro and containers of hot and cold water, we graphed the change in temperature versus time and found an exponential relationship. While many people are uncomfortable with exponential relationships, they are vastly important to science. As Albert Bartlett put it, "The greatest shortcoming of the human race is our inability to understand the exponential function." While this might seem over exaggerated, in order to understand nature, we have to understand exponents and today I learned about many of these relationships in the lab which was great.