Cosmic Horizons

So, my plans for my blog through 2017 have not quite gone to plan, but things have been horrendously busy, and it seems like the rest of the year is likely to continue this way. But I did get a chance to do some recreational mathematics, spurred on my a story in the news. It's to do with a problem presented at the  2017 Raytheon MATHCOUNTS® National Competition  and reported in the  New York Times.  Here's the question as presented in the press: Kudos to 13 year old Texan, Luke Robitialle, who got this right. With a little thought, you should be able to realise that the answer is 25. For any particular chick, there are four potential out comes, each with equal probability. Either the chick is pecked from the left pecked from the right pecked from left and right not pecked at all Only one of these options results in the chick being unpecked, and so the expected number of chicks unpecked in a circle of 100 is one quarter of this number, or 25. AB...

It is now the twilight zone between Christmas and New Year. 2016 has been a difficult and busy year, and my recreational physics and blogging has suffered. But it is time for a rebirth and I plan to get back to the writing about science and space here. But here's some things from 2016. A Fortunate Universe: Life in a finely tuned cosmos  was published. This has sucked up a huge amount of time and mental activity, and that continues. I will blog about the entire writing and publishing process at some point in the future, but it really is quite a complex process with many mine-fields to navigate. But it is done, and am planning to write more in the future. We also made a video to advertise the book! I've done a lot of writing in other places, including  Cosmos magazine on "A universe made for me? Physics, fine-tuning and life" , and commentary in  New Scientist  and several articles in  The Conversation  including Peering into the future: does sci...

After an almost endless Sunday, winter has arrived with a thump in Sydney and it is wet, very, very wet. So, time for a quick post. Last week, I spoke at an  Early Career Event  in the Yarra Valley, with myself and  Rachel Webster  from the University of Melbourne talking about the process of applying for jobs in academia. I felt it was a very productive couple of days, discussing a whole range of topics, from transition into industry and the two-body problem , and I received some very positive feedback on the material I presented. I even recruited a new mentee to work with.  What I found interesting was the number of people who said they had decided to be a scientist or astronomer when they were a child, and were essentially following their dream to become a professor at a university one day. While I didn't really discuss this at the meeting, I have a confession, namely that I never wanted to be an astronomer.   This will possibly come a...

There was a movie, in the old days, Journey to the Far-Side of the Sun  (also known as Doppleganger) which (spoiler alert) posits that there is a mirror version of the Earth hidden on the other side of the Sun, sharing the orbit with our Earth. The idea is that this planet would always be hidden behind the Sun, and so we would not know it there there. This idea comes up a lot, over and over again. In fact, it came up again last week on twitter. But there's a problem. It assumes the Earth is on a circular orbit. I won't go into the details here, but one of the greatest insights in astronomy was the discovery of Kepler's laws of planetary motion , telling us that planets move on elliptical orbits. With this, there was the realisation that planets can't move at uniform speeds, but travel quickly when closer to the Sun, while slowing down as their orbits carry them to larger distance.  There has been a lot of work examining orbits in the Solar System, and you can  s...

A long time ago, I wrote a post about the  Physics of Rendezvous with Rama , a science fiction story by  Arthur C. Clarke  set on an immense alien spaceship. The spaceship rotates, providing the occupants with  artificial gravity , a staple of science fiction. I mentioned in the article that I am not an immense fan of a lot of science fiction, as much of it relies on simple "magic", but Clarke knew his physics and so he knew that the "gravity" experienced in the rotating ship will differ to that on Earth, and previously I wrote about what happens if you jump off a cliff. In the last week, there was a question on twitter (it's an internet thing) about the movie  Elysium  which has a spectacular rotating spacecraft with the Earth's rich abroad. While it's a shame that the plot was not as spectacular, the question was how can such a station keep it's atmosphere. This is an interesting question, as you might think that it would all simply zip off...

Wow. It's been a while since I have written a blog post. Much of this is because of work and travels, and book writing (more news on that in the near future). But I'd like to get into blog writing, so here's a little science musing. Is an elephant heavier than a mouse? Now, you are probably saying "well, of course". Surely event the heaviest mouse weighs less than the newest born baby elephant, so why am I asking such a stupid question. Well, because science can never really  prove that an elephant is heavier than a mouse. I know, I've gone and put that word in, and I've written about how  proof has no place in science.  But let's examine this in a little more detail. I've stressed many times before that while measurements are important in science, without an uncertainty  such measurements are useless. And while professional scientists pour over papers focused on the error bars in figures, errors and uncertainties are typically waived ov...

A long rainy Easter weekend in Sydney. And, as promised, here's some additional musings on an academic career. I thought I would tackle a big one and present the question that all ECRs and wannabe-academics should be asking themselves from day one, and it's a question that all academics should ask themselves periodically (where the period of periodically can be as short as 5 minutes). Namely, "Do I really want an academic career?" Now, I am sure that some of you reading this, especially the more junior researchers of you, will be thinking "Well, duh! Ain't that obvious?" But, in fact, I think this goes to the heart of many of the touted problems with regards to academia, and it's a problem of our own making, and I mean all of us. But before I start, the usual caveats apply. While this year marks two decades since I got my PhD and so I have a long history with academia, and while I am a professor at a large, prestigious university, I have limited...

As promised, I'm going to put down some thoughts on academic careers. In doing this, I should put my cards on the table and point out that while I am a full-time professor of astrophysics of the University of Sydney, I didn't really plan my career or following the musings given below. The musings come from take a hard look at the modern state of play in modern academia. I am going to be as honest as possible, and surely some of my colleagues will disagree with my musings. Some people have a romantic view of many things, including science, and will trot out the line that science is somewhat distinct from people. That might be the case, but the act of doing science is clearly done my people, and that means all of the issues that govern human interactions come into play. It is important to remember this. Now, there may be some lessons below for how to become a permanent academic, but there is no magic formula. But realising some of these lessons on what is at play may help. ...

Still struggling with grant writing season, so another post which has resulted in my random musings about the Universe (which actually happens quite a lot). In second semester, I am teaching  electricity and magnetism to our First Year Advanced Class . I really enjoy teaching this class as the kids are on the ball and can ask some deep and meaningful questions. But the course is not ideal. Why? Because we teach from a textbook and the problem is that virtually all modern text books are almost the same. Science is trotted out in an almost historical progression. But it does not have to be taught that way. In fact, it would be great if we could start with  Hamiltonian and Lagrangian  approaches, and derive physics from a top down approach. We're told that it's mathematically too challenging, but it really isn't. In fact, I would start with a book like  The Theoretical Minimum , not some multicoloured compendium of physics. We have to work with what we have! ...

I need to take a breather from grant writing, which is consuming almost every waking hour in between all of the other things that I still need to do. So see this post as a cathartic exercise. What makes a scientist? Is it the qualification? What you do day-to-day? The association and societies to which you belong? I think a unique definition may be impossible as there is a continuum of properties of scientists. This makes it a little tricky for the lay-person to identify "real science" from "fringe science" (but, in all honesty, the distinction between these two is often not particularly clear cut). One thing that science (and many other fields) do is have meetings, conferences and workshops to discuss their latest results. Some people seem to spend their lives flitting between exotic locations essentially presenting the same talk to almost the same audience, but all scientists probably attend a conference or two per year. In one of my own fields, namely cosm...