According to current estimates, matter and energy, atoms and molecules started to appear more than 13 billion years ago, bringing about the birth of chemistry, physics and the universe. Planet Earth began forming about 4.5 billion years ago, with the first organisms emerging 3.8 billion years ago. Numbers like this blow the minds of most regular humans, but it’s more familiar territory when you’re an Extragalactic Astronomer.
Dr Tanya Hill is our local Planetarium Curator, frequent visitor of Advieh and Corner Shop, and Yarraville resident. Her thesis was titled ‘Starburst or Active Galactic Nuclei; Investigating the Properties of Energetic Galaxies’.
“The simple explanation is that I hunted for black holes, and an Extragalactic Astronomer is someone who studies deep space, way way out. Our planets and our solar system is too close for me, even our stars and our Galaxy is too close. I look beyond our Milky Way Galaxy”.
Moving over from Sydney nineteen years ago, Dr Hill and her then fiancé (now husband), were finishing off their PhDs when she was offered the opportunity to manage the Planetarium in Spotswood.
“The first 18 months was hard going, we were missing home and staying with friends in Ascot Vale. My husband was invited to dinner with a friend at Fidama’s, and I instantly fell in love with Yarraville and the village. I couldn’t believe I had been driving past it this whole time, within two weeks we were renting there and have never left. It made Melbourne home.”
Dr Hill has a special gift of explaining complex ideas in simple terms. She dreamed of being a teacher when she grew up, giving lessons to neighbourhood kids on her blackboard.
“Astronomy was more of a sideline. I always looked up at the sky but it wasn’t until university that I got to work with an astronomer at the Australian Astronomical Observatory, and realised you could do this amazing stuff as a career. I love that I have come full circle and have incorporated education into astronomy”.
The Planetarium at Spotswood has been a fixture on the school excursion circuit since it opened, and the very first exhibition ‘Tycho to the Moon’ is still one of the most popular after eighteen years.
“I really see my role at the Planetarium as keeping up to date and forging those links with researchers, and translating it for the public. ‘Capturing the Cosmos’ is a collaboration that began while catching up with a friend. Three years later, after working with many astronomers, the show focusses on current Australian astronomy research and we’ve received fantastic feedback from visitors”.
Like everything, the study of space has been hugely impacted by technology.
“When doing my PhD, I studied twenty-five galaxies – they were my children! Now using optical fibres, you can study four hundred galaxies at once, and collect thousands of galaxies in one night. You can see how the gas is moving and the stars are forming across different sections of the galaxy. We are at the point with the telescopes we are building that we don’t even know how to store that much data, or how to work with it. It’s more information than we have ever seen. “
The Hubble Space Telescope (HST) was launched April 3, 1990 and changed the way we view the universe. It gave astronomers the ability to see remote galaxies, looking further and in more detail than ever before. The best optical telescopes for each hemisphere are in Hawaii and Chile – the latter having a set of four telescopes each with an eight metre diameter (the Very Large Telescope), but currently building one with a thirty-nine metre diameter (the Extremely Large Telescope). Australia recently joined the European Southern Observatory giving us access to these telescopes in Chile, potentially leading to extraordinary findings in the near future.
“I have two favourite constellations in the southern sky depending on the season. In Summer, it’s Orion There’s a fuzzy star in Orion that you can see with the naked eye, but using a telescope, you can get to see the whole Orion Nebula which is a star-forming gas cloud and just beautiful. In Winter, my favourite constellation is Scorpius – which is also my birthday, and this is when we move into dangerous territory. The Sun is in a different constellation roughly every month, and I love this idea that when we are born, we have a connection to a particular star sign – but that gets hijacked by the astrology angle which is going too far!”
Aboriginal astronomers are the world’s oldest astronomers and like many indigenous populations, the stars were used to navigate the land and develop calendars that informed when they hunted and gathered, depending on the season. The animals that are seen in the night sky depends on the local geography.
“Ten years ago, we worked with the North-west Nations clan, and put together a show called ‘Stories in the Stars: the night sky of the Boorong people’. An early pastoralist by the name of William Standbridge wrote down the stories of the Boorong and it’s one of the most comprehensive documentations of indigenous stories relating to the night skies. It’s lovely because it’s kangaroos, emus and eagles and all those familiar things. One of the really interesting things is that rather than connecting the stars like dots, often the absence of light – the dust clouds, became the image, such as with the emu.”
The Boorong people had a very sophisticated understanding of the stars. Their location was around Lake Tyrrell (Tyrrell means ‘space’), near the South Australian and Victorian border, which has become a mecca for star gazers due to the incredible reflection of the milky way in the lake.
In current astronomy, much fascination lies with the Dark Ages – a period of time between the Big Bang and the creation of the first stars. It was literally dark, but is also a time of mystery, when what was happening in our universe is a complete mystery.
“The big question right now for astronomers is how did the very first stars light up. I love the idea that looking back into space, means looking back in time. We are looking back and seeing the history of the universe. We never see things in real time, even right now I am seeing a version of you from nanoseconds ago because of the time it takes for light to travel!”
Whilst this might excite astronomers, the big question for the general public remains – is there life in the universe, which leads us to exoplanets. Exoplanets are planets that orbit another star, and the first rocky planets orbiting a pulsar in the constellation of Virgo, were discovered in 1992. As Dr Hill explains,
“The only reason we have oxygen in our atmosphere is because there is life here on Earth. Oxygen doesn’t hang around, it usually disappears, it’s only because we have plants that it’s always replenishing. If we can pull apart the atmosphere of one of these exoplanets and see if it has oxygen, it would be a huge indicator of whether there is life. This could happen in the next couple of decades, which is exciting because a few decades ago, we didn’t know that exoplanets existed.”
One thing Dr Hill would like to clear up with the public is the recent ‘Super Moon’ phenomenon. With 250 people attending the viewing of the recent ‘Super Blue Blood Moon’ at the planetarium, and the conversation on social media, she feels the need to clarify:
“Before 2011, the term super moon didn’t even exist! It’s this ridiculous notion of where we know more, and then we understand less. Yes, the Full Moon is slightly closer to us at certain times of the year, but it’s not enough to really stand out and notice. It is my bugbear at the moment that information gets shared around without people really thinking about it.”
If you would like to hear more from Dr Tanya Hill, she and her team are hosting adults only sessions of ‘Planetarium Nights’ every Friday evening, that includes ‘What’s in the Night Sky?’ along with fulldome film screenings of the cosmos, galaxies and black holes. You can buy tickets online from https://museumsvictoria.com.au/scienceworks/whats-on/planetarium-nights/
You can read more from Dr Tanya Hill on The Conversation https://theconversation.com/profiles/tanya-hill-121214