Thursday, July 21, 2011

Fun With Light

This morning was a little rough. Between class, lab reviews, exploring the city and meeting so many new people, not much time is left over for sleep, so getting out of bed can be difficult. Once class begins, it usually gets better. Today, we had three hour-long lectures in a row that were each very interesting, but sitting in one place for that long was still quite difficult.

Luckily, the topics of each of the presentations were intriguing enough to keep me awake. Mary took the first shift, giving us a lot of information about the Standard Model. She talked about the subatomic particles, most obviously protons, neutrons and electrons, but also the components that make up protons and neutrons (which happen to form in such a way that they have polar charges, allowing positive protons to exist so close to one another), as well as anti-matter such as positrons and anti-protons. It was really fascinating stuff and a lot of the tings she went over, I was hearing for the first time but it really helped me understand the way atoms work on a much deeper level.

Our next lecture was a guest lecture about how general relativity is proven by gravitational lensing. He basically explained that a massive object can bend the light coming from the objects around it and if it lines up perfectly with a light source directly behind it, observers from earth see the light source as a ring around the massive object. These rings are called Einstein Rings and we can use them and other examples of bent light to understand more about both the light sources and the dark matter and black hole in the universe that have mass and therefore bend light but are otherwise decidedly inactive. In fact, gravitational lensing turns out to be one of the few ways we can measure dark matter. After the talk, we got to play with lenses made to bend light in exactly the same way a black hole would.

The third and final lecture was performed by another guest, James Aguirre. He discussed with us some of the work he is doing with telescopes that use regular FM radio waves to get an image of the distant galaxies in the universe. He showed us some of the pictures he took of the 60 something radio receivers he set up in a desert in Africa, away from interfering signals, in order to collect his data. Based on the images he showed of the maps of the universe his telescopes have already created, it's clear he is doing some groundbreaking work. He also discussed with us the next step he would be taking to collect even more meaningful data in the next five years or so.

After all the lectures, we had a well deserved break for lunch and when we came back we split back up into our interest groups. Because quantum mechanics was done collecting data, we watched the Feynman lecture on particle/wave duality. It was really cool because he is really good at explaining the complex ideas of quantum mechanics in understandable ways and also because he mentioned specifically the exact experiment we had already done with the photo multiplier and the diffraction pattern. We also worked on a power point for our presentation on Wednesday before leaving.

After class, Brian, his floor mate Abheek and I met up with Tom Miller from the Yale ILC group on campus and we sat in the grass and under the shade of a nice big tree. We were planing on playing a game of Frisbee, but in 9o degree weather, the shade-sitting idea was much more appealing.

At 7:00, we got dressed for another fancy dinner with our ILC cohorts. There were many guests present: three students from U Penn as well as other faculty. I was seated next to Britney, a rising senior at Penn who majors in Psychology and is striving to become a pediatric psychiatrist. She had some really interesting things to share about the possible clubs, the options for housing and dining, and all there is to do in Philly. It was great getting to hear from her. I also talked briefly with Ellen Kim, the UPenn admissions councilor for Northern California, about how much I was enjoying my classes and why I was interested in physics in particular. We went on to discuss the types of people who are drawn to Penn and those who are accepted, specifically, those who have interests of their own but are also open-minded and willing to study across disciplines and hear what the community has to share. It definitely gave me a better feel for the place listening to all the guests and what they had to say about Penn.

When we returned to the quad, we walked into something very peculiar. A group of about ten students were standing in a strange formation waving glow sticks around very slowly in seemingly random directions. Upon closer inspection, I realized there was a camera set up in front of them. They were making light paintings with high exposure shutter speeds. it looked like too much fun to resist, so I grabbed a glow stick and joined in. It was great. We worked together to spell out "UPenn", draw a giant dinosaur, a man shooting another man with a laser beam, a family with a puppy, and a bunch of just random shapes. We ended up with some really cool pictures. I'll try to get a hold of them and post them tomorrow. It was a great end to a long day.

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