 We've found what we think are the oldest stars in the galaxy and potentially the oldest objects ever discovered, probably only from maybe 100 million years after the Big Bang so they've been around for longer than the galaxy has itself, pretty much the galaxy formed around them. They would have formed around the time that astronomers called the epoch of realisation and that's the time when the first photons were starting to be emitted from stars and it was pretty much the earliest things we can ever see. These stars are pretty small. They'll be about 50 times the size of the sun but only about the same weight. There are two reasons for us to think that they are that old. Firstly because they are lacking a lot of metals in the atmosphere so we see them as being very clean and secondly because they're very close to the centre of the galaxy. They are where we expected them to be. The places where the very first stars would have formed would be in the most dense regions of the universe. We expected them to be lacking in metals but we also found that they were lacking in elements such as carbon and magnesium. We would expect that the carbon and magnesium would have come from a previous generation of stars that exploded very quickly and polluted the gas that these stars formed from. So what we think is that the relatively small stars for some reason had 10 times the amount of energy that we would expect and exploded in what we call a hypernova and that would shoot out a lot of elements like iron and nickel and not so much of the carbon and magnesium. I'm just fascinated to be able to look at these stars that happened so long ago that we can possibly work out how the Milky Way formed. The Milky Way is so massive and we're only such a small part of it that what I hope to be able to do in the future is to work out exactly how the Milky Way formed and these stars are the very first building blocks of that. So we're lucky here at ANU to have the SkyMapper telescope and SkyMapper can observe hundreds of thousands of stars in just a single second. So what we did is we pointed SkyMapper at the centre of the galaxy and observed about 5 million stars using the filters established which ones we thought were most likely to be old and then we followed those up with high resolution studies looking at the ones we expected to be the best. And the fact that they're not quite what we expected is very exciting. A lot of astronomers predicted we would be wrong about these stars because there's a lot of history going back looking for these stars in different places. So to prove some people wrong as well is pretty good.