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Western Sydney University is advertising research projects for prospective masters students. You’ll find one from me about our impending collision with the Andromeda Galaxy. (Well, if you can call a few billion years “impending”.)

Will we survive the Andromeda collision?

Supervisors: Luke Barnes (Data Science, Astronomy)
School/Institute: School of Computing, Engineering and Mathematics

The Milky Way’s nearest galactic neighbour – of similar size – is Andromeda, located 2.5 million light years away. We know that Andromeda is moving towards us at about 300 km/s, which means that it will arrive at the Milky Way in about 2-3 billion years. What happens when it arrives?

More details about the project. More details about enrolment.

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Reposted from Sydney Observatory:

Verlie Lee passed away on 15th June 2019 in Nambucca Heads and Eungai Creek on the North Coast of NSW at the age of 88. Verlie worked at Sydney Observatory from 1948 to 1954 and she was one of the many ‘hidden figures’ who worked on the Astrographic Catalogue, tides and other charts in observatories during that period. Recently the work many women did behind the scenes in science is being brought to the fore and it is timely to remember Verlie June Maurice’s contribution. I interviewed Verlie Lee on 3 April 2013 and she had many stories of the work and social life at Sydney Observatory which she was keen to share.

Five women star measurers on Observatory Hill in Sydney in front of the rotunda.
Star measurers and computers at Sydney Observatory. Top row left to right: Verlie Maurice, Patricia Lawler. Bottom Row left to right: Margaret Colville, Renae Day, Margaret Browne. Photograph by Winsome Bellamy, 1948.

The Astrographic Catalogue was arguably the most significant astronomy project undertaken in the late nineteenth and early twentieth century in Australia. Sydney, Melbourne and Perth Observatories were part of an international consortium of observatories working together to catalogue the stars using photography. Whilst predominantly men took the photographs of the stars using special ‘astrographic telescopes’, women measured the stars on glass plate negatives, calculated their positions, identified double stars and other irregularities. Verlie was one of 22* women who measured the positions of stars for the Astrographic Catalogue at Sydney Observatory between 1916 and 1963. Continue Reading »

New! With Geraint Lewis, from Cambridge University Press, in Feb 2020:

9781108486705pvs

Free yourself from cosmological tyranny! Everything started in a big bang? Invisible dark matter? Black holes? Why accept such a weird cosmos? For all those who wonder about this bizarre universe, and those who want to overthrow the big bang, this handbook gives you ‘just the facts’: the observations that have shaped these ideas and theories. While the big bang holds the attention of scientists, it isn’t perfect. The authors pull back the curtains, and show how cosmology really works. With this, you will know your enemy, cosmic revolutionary – arm yourself for the scientific arena where ideas must fight for survival! This uniquely-framed tour of modern cosmology gives a deeper understanding of the inner workings of this fascinating field. The portrait painted is realistic and raw, not idealized and airbrushed – it is science in all its messy detail, which doesn’t pretend to have all the answers.

More details here.

 

Another edition of “How to Use Bayes Theorem Properly 101” (links to previous posts are below). I was listening to a YouTube debate, and one of the speakers offered the following definition of “evidence”:

Evidence is a body of objectively verifiable facts, that are positively indicative of or exclusively concordant with one particular conclusion over any other.

They then demonstrated the many fatal flaws of this definition; for example, there is no such thing as objective verification of facts. Here, I’ll focus on another flaw. Continue Reading »

(This is a repurposed Facebook comment.)

The Fine-Tuning Argument (FLA) is accused of committing the Texas sharpshooter fallacy. Sam the shooter wants to hit a bullseye, but isn’t having much luck. They can barely hit the side of a barn. Having sprayed bullets at the barn all day, they devise a plan: pick an arbitrary bullet hole, paint a bullseye around it, ignore the rest of the bullet holes, and announce themselves to be a sharpshooter.

The moral of this story can be stated in a few ways. Don’t ignore data. Keep in mind the number of failed attempts when you go looking for (and set a criterion for) successful attempts. You can avoid these problems if you specify your hypothesis before you collect your data. Drawing conclusions from a sub-sample is dangerous – if you must, try to choose a random sub-sample.

A Bayesian Sharpshooter

Let’s put the tale of Sam in Bayesian terms, and then see if it applies to the FTA. Suppose,

  • S = Sam is a sharpshooter
  • \bar{S} = Sam is not a sharpshooter.
  • T = Sam said “I’m going to hit that painted bullseye with this shot”, and then he did.
  • P = Sam shot at a wall, and then painted a bullseye around his shot.
  • B = background information about guns and bullets and such.

In both cases T and P, we observe a bullet at the centre of a bullseye. The difference between the cases is as follows. Sharpshooters are much more likely to hit a given target than non-sharpshooters, thus: Continue Reading »

Want to simulate some other universes with me? Looking for life in a (simulated) cosmos? Desperate to test some multiverse theories? You too could make classy videos like this!

Using supercomputer simulations of galaxy formation, we will investigate the effect of fundamental cosmological parameters on structure in the universe. We will model the formation of galaxies in lumpier and smoother sub-universes, and universes with different amounts of dark matter. Our group has previously explored the effect of the cosmological constant (arxiv.org/abs/1801.08781), and will extend and expand this approach, working with a world-leading galaxy formation code.

What does the scholarship provide?

  • Domestic students will receive a tax-free stipend of $30,000 per annum for up to 3 years to support living costs. Tuition fees will be supported by the Research Training Program (RTP) Fees Offset.
  • International students will receive a tax-free stipend of $30,000 per annum to support living costs. Those with a strong track record will be eligible for a tuition fee waiver.
  • All international students are required to hold an Overseas Student Health Care (OSHC) policy covering the duration of study, with the scholarship including funding for Single cover.
  • Support for conference attendance, travel and additional costs as approved by the School.

For eligibility conditions, and to apply, see the details here.

Applications close on October 14.

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I’ve got a few talks upcoming in Sydney. Come and see the show!

2 August 2018, Sutherland Astronomical Society

Title: Following Light to the Beginning of the Universe
Time: 7:30pm – 9:30pm
Location: Green Point Observatory, Oyster Bay
Free. (I think. Maybe a gold coin for tea and coffee). More details here.

Abstract: How do we know what the Universe is made of? And what shapes its parts into the stars, galaxies and clusters of galaxies that we see around us? Starting from the very early universe, I’ll discuss how the fundamental factors of our universe, its forces, particles, and the dynamical stage that they tread (space time), compete and cooperate to fashion the Universe today.

5 August 2018, St Mark’s Darling Point

Title: The Big Questions – Science and God
Time: 8am, 10am and 5:30pm
Location: 1 Greenoaks Ave, Darling Point NSW 2027
More details here.

10 August 2018, The Australian Botanic Garden (Mount Annan)

Event: Stars over the Garden

Come and enjoy the beautiful Garden under a starry sky! You will learn about Western and Aboriginal views of the night sky.

Dr Luke Barnes, astronomer at Western Sydney University will introduce you to the night sky over Mount Annan and the Macarthur Astronomical Society will bring out their telescopes so you can experience the best views. Our Aboriginal educators from Shared Knowledge will share their dreamtime stories about Australian sky and talk about how the visibility of certain star signs influences their lives.

If the weather permits you will have the opportunity to watch the stars and planets close up through the telescopes. A glass of wine will round up an amazing night experience.

Time: 4.45 pm-6.15 pm
Location: Narellan Road, Mount Annan 2567
Cost: $29.00 per person / Garden member $25.00. No walk-ins. Tickets must be purchased in advance here.

13 August 2018, St. Luke’s Clovelly

Title: The Big Questions – Science and God
Time: 7.45 for snacks, 8pm start
Location: Corner Arden St and Varna St, Clovelly (location)
More details here.

17 August 2018, Centennial Park

Event: Astronomy in the Park

Immerse yourself into a night of stargazing. Looking up we see the bright and the dark – explained by our scientists of the Sydney Observatory, and by our aboriginal educator who will share his stories about the sky with us. At our telescope station, you will have the chance to observe the sky and ask our scientists about the phenomena you discover.

Once you and your group have discovered the sky and the park, we will wind up the evening at a campfire where you can relax, reflect the stories you heard, and enjoy a night in the park under the stars.

Time: 5pm-7pm
Location: Wild Play Discovery Centre, Dickens Drive, Centennial Park
Cost: $29.00 adults / Children $15.00. Find more details and purchase tickets here.

21 August 2018, Narrabeen Baptist

Title: The Big Questions – Science and God
Time: 7:30pm – 9pm
Location: 13 Grenfell Ave, North Narrabeen (location)
More details here.