Question: Hello, What sort of stuff does Mt. Stromlo Observatory currently investigate?

There are lots of people studying all sorts of things. Some scientists study the Earth and Moon, how they formed, while others are trying to understand life and look for it on other planets. Some other astronomers are looking at other stars trying to find planets around other stars. Quite a few astronomers study stars, galaxies, and black holes and how they all formed, evolved, and work together. There are also those like me that study what makes up the Universe and how it began. We also have people who build telescopes and instruments to put on them.