Question: What did you find out about in your doctorate in astrophysics?

Sam Geen answered on 17 Jun 2013:

My subject was “feedback in dwarf galaxies”. Feedback is a process where what comes out of a system changes what goes in. It’s like when a microphone picks up the noise from a concert and makes a screeching sound – the sound loops back through it and makes a big noise. The same is true in galaxies – stars form from gas, but some of them explode and blow away some of the gas, which changes how many stars form later. A dwarf galaxy is a small galaxy, ten times smaller than our Milky Way galaxy or more.

I looked at how the dwarf galaxies that orbit our Milky Way evolve – I found that the hydrogen gas in our galaxy is important for describing how they evolve, because when one passes through our galaxy the gravity from the galaxy’s sprial disk pulls it apart.