Science AMA Series: I'm Joss Bland-Hawthorn, ARC Laureate Fellow Professor of Physics and Director of the Sydney Institute for Astronomy, Sydney, Australia. I specialize in extragalactic and galactic astronomy, and in developing astronomical instrumentation. AMA!


Research is an exhilarating journey of discovery; you learn something new and exciting each week of the year. My team at the Sydney Institute for Astronomy is working on the next generation of astronomical and space instruments. On April 19, one of these CubSats launched from Cape Canaveral to the International Space Station. Our CubeSat is one of the first Australian satellites to be sent into orbit in 15 years. A proud time for our team!

I am an ARC Laureate Fellow Professor of Physics and Director of the Sydney Institute for Astronomy (SIFA). I was born in England before moving overseas in 1985. After receiving my PhD from the Royal Greenwich Observatory and the University of Sussex, I took a 3-year postdoc in astrophysics at the Institute for Astronomy, University of Hawaii. In 1988-1993, I was a tenured professor at the Space Physics & Astronomy Department, Rice University, Texas. In 1993, I joined the Australian Astronomical Observatory, Sydney. In 2000, I was appointed Head of Instrument Science, a new division that was created to reflect the increasing need for complex novel solutions to astronomical instrumentation. Since 2007, I have been a professor at the University of Sydney. I am a Fellow of the Australian Academy of Science and The Optical Society (OSA).

I will be back at 7 pm ET (9 am Sydney Time) to answer your questions, ask me anything!

What are some thing you would say/suggest to someone with a budding interest in astronomy. Books to read, academic subjects to focus on, current astronomical projects to look into, etc.


It depends what level you are at, i.e. in school before Uni, at Uni, someone with a non-science job, etc. There are so many good self-help books. I am impressed with amateur astronomy clubs who seem to have so many avenues for learning and getting into telescopes and instruments. Amateur astronomers make a serious contribution to the science in key ways. There's also citizen science projects like GalaxyZoo. If you want to become a professional, you can either take an online course (e.g. Swinburne lectures) or start to take science/math subjects at Uni. It's like becoming a medical doctor, it's a long road but great fun if you love it.

What is the most mind blowing fact you can share with us


I would say the idea that there must be missing dimensions in the Universe is just wild! crazy even! but it might even be right and future LHC experiments might reveal some of them??

Is there a chance that everything we observe about the universe is wrong due to the way we are observing it? For example could there be something near to us that distorts how light reaches us thus causing everything to look blurry?


There's a paper by colleague R.D. Blandford that talks about how gravitational lensing from all the intervening blobs of mass distorts what we see overall, but it's not a big effect. There are lots of clever papers on how the Universe is some kind of hologram, but I've never understood them. You can come up with all sorts of clever ideas for how the Universe we see is not what it really is, but whatever model you do construct, it must be testable. A lot of scientists have a hard time with multiverses because the idea has not been shown to be testable in a rigorous way. That's what's amazing about physics and astrophysics, that so much of what we see does appear to be understandable. It's possible there are things that are beyond our understanding for all time, but I don't think we know that for sure, say, specifically how the Big Bang occurred.

How will quantum physics and quantum computing change astrophysics?


Quantum physics is central to all of astrophysics, I mean all of it. I don't think quantum computing is directly relevant as defined now. there is a crossover field on quantum information and quantum computing that has promise... e.g. understanding black holes.

Of the stars and other celestial objects one can see in the night sky, about how many of them are outside of our own galaxy?


With our eyes, we see 6000 stars at sea level. With telescopes, we can infer the presence of 60 billion stars in our Galaxy if all the mass of the Sun, in reality there are closer to a trillion stars since so many very low mass. Would you believe there are a trillion galaxies with a trillion stars? A trillion trillion stars in the Universe is about the number of grains of sand on Earth... When you hold your thumb up to the night sky, you are blocking out millions of galaxies in that patch. Amazing...

Have you ever experienced difficulties in studying during your undergrad? Difficulties as in, getting barely passing grade/failed a subject, retaking some subjects, etc.? After undergrad was it the same or just a breeze? Last thing: give your ultimate study tip


Absolutely. I think we all struggle at each step of our journey. The trick is to just keep going, even if everyone around you (pretends to) make it look easy. Drive and enthusiasm counts for at least half of anyone's eventual success... My absolute favourite formula is to work hard for two hours, 20 mins relax, 2 hours, relax... etc. And then after a week or so, do something completely different. The brain is awesome at solving things when you're not thinking about them. It organizes and the solutions come. My secret all my career...

What is an often overlooked design aspect of space instrumentation? examples being interference from magnetic fields, vibration resistance, possible loosening of connections ect.


I think one of the hardest problems is being aware of which materials behave badly in a vacuum, e.g. outgassing, subject to high energy particles generating bursts of light (cerenkov radiation), solarization (blackens coatings and glasses), etc. This is a minefield. I wish I know more about material science... some materials are literally cooked in situ by the energetic particles, and go hard or change state.

Hi! I recently became interested in radio astronomy. I was wondering how a receiver like the RATAN-600 is able to receive signals, versus a facility like Arecibo. Arecibo has a giant hemishperical dish, whereas the RATAN appears to be a giant ring in the dirt. How are these two wildly different designs able to achieve the same task? Sorry if it's a very basic question...


I've never seen the RATAN before - weird. It must use the Earth's motion to fill out its "beam." This means the atmosphere above the telescope had better be stable so you can form an image. Here in Australia, we have a "linear" radio telescope at the Molonglo Observatory; this also uses the Earth's rotation. A single dish like Arecibo doesn't need the Earth's motion to fill out its beam; it gets a "single filled aperture" measurement wherever it looks.

What are your thoughts on Tabby's Star?


It's got nothing to do with alien megastructures, you can be sure of that. Something like a cloud of fragments in orbit about the star could easily explain what you see... the flickering signal would be different each time because bits of stuff in the cloud move around within the cloud. It could even be more than one cloud of stuff on like a Trojan resonance orbit, e.g. as we see around Jupiter. Look up the Trojans / Jupiter on Google. I was very surprised when a reputable journal accepted papers on alien megastructures! I would have not allowed this for a simple reason: extraordinary claims require extraordinary evidence !!!

Hey joss! You're awesome ! We know each-other IRL: we've been to a bunch of conferences together but never mind for now.

Question: aren't you a little embarrassed that we have no idea what dark matter or dark energy is? I feel like as cosmologists we have one of the most precise and powerful descriptive models in science. We can measure cosmological parameters to fantastic precision but we have NO IDEA what dm/de is? I mean it would be great if it were a sterile neutrino or if we get evidence that the equivalence principle is broken and that DE is some kind of modified GR, but isn't time running out to figure out what this stuff that dominates the universe really is? What if in 3 decades were still talking about "dark matter" this and "dark energy that"???


I agree with everything you say. If I had any answers, I'd be off to Stockholm on the next train. But hey, one can only hope... I bet we don't solve DM and DE any time soon. Some of the cutest ideas I've seen talk about space-time leakage, coincidentally the latest issue of the New Scientist. I do wonder about all of our conservation principles which may not operate on the largest cosmological scales, i.e. remnants of the Big Bang...

When you and your team build a complex instrument, do you get a chance to use it too? It could be a bit unrequited being the tool-maker but not the tool-user.


In my particular case, my group tries to build things that we can use, i.e. our science. But you're not always given that option. There are some people who are devoted to delivering instruments that they will never use, but they delight in seeing the instrument used successfully. Astronomy does not give enough credit - not by a royal mile - to all the clever instrument builders and engineers. Some people build huge reputations on simply turning the handle and producing results that anyone could have come up with. That's one of the sad aspects of how science is done, disproportionate reward. The Nobel Committee get that right to a large extent by trying to identify who made the experiment happen and did all the really hard work; NASA does a good job too. But the astronomical system of rewarding prizes and, for that matter, advancing careers, is not so good. We still don't have a single major prize for the leading experimentalists in astronomy & astrophysics, no idea why. I can think of dozens of amazing people who have been left behind over many decades.

What are you hopes for humanity in the distant future pertaining to space exploration?


I think it's entirely inevitable - you can't stop humans pushing the boundaries. There are good arguments based on our long-term survival as a race, as well. But it would be tragic if humans consider space as an option after wrecking our own planet. The Earth is by far the most hospitable place to live, and by far the most ideal for human existence. It would take tens of thousands of years to find anything as good.

Typically what does your work entail when you are working in the field of astronomical instrumentation?


A lot of the time, you talk to lots of astronomers and get ideas on what science interests them. You also have your own ideas. I tend to go with our strengths, i.e. which telescopes do we have access to, which people are likely to use your concepts, can we achieve new science within a few years? I think I'm too impatient to spend 30 years developing LIGO or Gravity Probe B, say. But of course, that would have been a wonderful track to be in, esp. if you are developing enabling bits of the experiment. So my group does optical and mechanical design and prototyping. Then testing at the telescope. We try to deliver something useful for a fixed budget. If all goes well, we try to expand the idea into something much bigger if useful. Much of our work has been to introduce photonic components into our instruments, like they have in telecom, e.g. fibres, waveguides, FBGs, optical circulators, and all sorts of crazy devices. We can use with other optics although some of our instruments are fully integrated. We've launched the first ever photonic spectrograph on the Inspire-2 cubesat a few weeks ago. You can follow me on twitter @jossblandhawtho and look back at those tweets, links to movies in space, etc.

Do you use any programming language / skills in your work, like to code stuff for the components you create our the research your are doing? If so, how did you learn the required skills and what programming language so you use?


Nowadays, everyone is big on Python, although Fortran and C still get used. For the machines, symbolic languages like Labview are good. We also use environments like Mathematica, Matlab, IDL. I spent a few months programming in PostScript once with a view to making printers and other output devices better, made lots of nice figs, but it didn't go anywhere. In my distant past, I programmed in Basic, Algol, Pascal, Lisp, ... for different applications. Now, I just want to get the job done, and don't spend time on perfecting my programming skills...

Does it feel sad that we won't be around to witness the milkdromeda? And does it feel really sullen that the expanding universe will one day reduce the amount of awesomeness we witness in the observable universe?


don't feel sad about it because we can run huge supercomputer simulations and "see" the eventual merger of the Milky Way and Andromeda in 4 billion years, give or take. I think being able to "understand" what's coming from years of training as an astrophysicist makes up for that disappointment. I guess science fiction movies and books also take you to exciting places, things we'll never see. "If you could have seen the things that I've seen..." I love that line from Bladerunner.

Do you envision humankind sending information gathering devices to other star systems? If so, how far might they be sent and what data would you want them to collect?


I think something like picosats might work one day powered by mm or microwave radiation, say, or possibly optical lasers. The hardest part is getting the picosat to slow down at the other end, rather than shooting past the star. We won't get much data if the picosat goes zipping by at 0.2c. One idea is to use radiation pressure from the star itself to slow down, so target bright not faint stars! I have this weird idea that what we will eventually try is to send billions of little crafts (size of detector pixels) that will assemble at the other end into something bigger. This system is then able to use power from the star, collect images, and send back a useful signal. I'd love to see it happen, but it may take a century to get this all together.

Any thoughts/opinions/hopes regarding Tabby's star?


see above...

Do you believe in a multiverse? If so what kind?


Only if the idea is testable - still waiting for someone to show me how to test for multiverses...

Is there any science fiction you can recommend as an astronomer?


I stopped reading Sci Fi twenty years ago. The books I remember as being good are "Foundation Trilogy", "Stranger in a Strange Land" and "Dune" of course. I always loved "Destiny Doll" by C D Simak, still haunts me. I tend to like books that are Sci Fi technology rather than fantasy, so not too far removed from our experience, e.g. John Wyndham, Greg Benford. The recent book about the man stuck on Mars was good fun because I could reason along with him. Lots of movies and books make a real hash of the science and I just give up with it. Mind you, my absolute favourite is Time Machine, still haunted by the book and B&W movie available on youtube!

Ive heard that super computers are used to simulate cosmological formula so how accurate are such simulations and how much can quantum computers improve cosmological simulations ?


The cosmological simulations are good on the largest scales, not at all good on small scales like star forming regions. I am not a big fan of quantum computing; we're many decades from truly useful devices IMHO. Lots of money, lots of ideas, but delivering on real devices and algorithms will take a long time. Cosmological simulations will get bigger and better on conventional technologies for decades to come.

Is there a development or an instrument that you wish you thought about earlier?


Hmmm, I am impressed by the Gravity instrument at the European Southern Observatory. That's an innovative instrument which I think will lead to variants in future years. Instruments that fully exploit adaptive optics with artificial stars high in the sky are the next big thing. We are promoting photonic technologies to achieve this, but there are other ways. I've not had any wow! moments with new ideas for a long time. It's very hard work to go from idea to realization if your goal is to break new ground. We have a crazy project under development now to do with twisted light - we want to check a published claim, but again lots of work, expensive, may not pay out!

How much resources should be allocated to astronomy (1) as opposed to all other basic research, (2) as opposed to global gdp? Or to put it differently, is now a good moment in human history to invest in astronomy?


I would say that some money for basic exploration is always a good thing. The public love the images from the Hubble; they are inspired by them. Astronomers push very hard on the technology (e.g. detectors) and this has led to benefits for society. Good examples include WiFi, web browsers, airline booking systems, clustered computers, photonic devices for next gen telecom, breast scan imaging, x-ray screening, radio receivers, sensors, and much more. I think there will be more benefits to come. But even without those societal benefits, it's still worth doing because we are all inspired by "what's out there." (If I am given X millions of dollars to spend across new ideas, I think of 0.8 X going to conventional ideas where you can see the end, 0.2 X as going to off the wall ideas.) There's never a perfect time to invest in pure science, so I would say some funding should always be made available year by year. Maybe astronomy's most powerful contribution to society, after inspiration, is the huge numbers of outstanding problem solvers we create that move across into all walks of life...

What "novel" solutions in astronomical observation do you find most promising? In your time heading Instrument Science, did you see any developing technologies that you think will prove useful in providing better optics/data collection?


I think the big one is adaptive optics (AO), i.e. correcting for the twinkling from the Earth's atmosphere. This blurs our images badly. We are now embarking on a new gen. of monster telescopes. There is no point in going down this path without excellent AO. I have been really impressed by progress. They fire a laser from the telescope up to the atmosphere and excite sodium atoms at 90km. it makes a spot of coherent light. We track how the star is pushed around and use deformable optics to correct our images. Even more impressively, we can use lots of artificial stars to make a bigger patch corrected for the twinkling. The recent images of Jupiter from the ground rival some of the early fly-by missions. Awesome!

What technology could catapult progress in your field? Thank you.


Nice question. Something like an optical (quantum?) computer that can process the light signal directly for all the information contained. One day, we'll have detectors which will tag time for each photon, I guess.

If you were personally given a million dollars and the only requirement was you had to spend it on something in your work related field, what would it go towards?


Right now, I would spend it on people to process the fantastic data we have coming in. If you were to force me to spend it on instrumentation, I would build a pair of cubesats that communicate with lasers.

If astronomical observatories were established on the far side of the Moon, would the resulting isolation from Earth noise be enough to justify the expense?


I think so. I love the idea of a huge dark-side lunar telescope. Maybe one day it will be affordable?

What's the difference between Ether, 1900 and dark matter, 2017?


I think aether was invented because early scientists could not see how light could propagate through a perfect vacuum. But Michelson & Morley killed off the need for aether. Dark matter, of unknown nature, is needed to explain excess gravity in and around galaxies. Most of us believe that, some do not. It might be very difficult to prove dark matter particles exist if they are a continuum of little things rather than a few specific particles. Time will tell.

Following the recent Japanese misfortunes, how long do you expect it will be before we have a state-of-the-art X-ray observatory? How much better will it likely be than what we have had so far? And, if given a block of time on such an instrument, what would you point it at?


It might take a few decades but there are big plans afoot. Yes, I really hope this happens. I'd point it at our Galactic Centre first - there's a flare there almost every day!

Do you believe in extraterrestrials life?


Yes. I think the Universe must be teaming with life at different times and places. The more interesting question is whether we can ever make contact in space-time. They may be very distant in space and or time.

I've been reading a book by Jim Baggott called Farewell to Reality. What are your opinions on all of the "fairy tale" theories about the universe (holographic universe, multiverse, etc) that have become extremely popular amongst the academic community and are being idolized to an almost quasi religious extent? Do you think this is hindering the development of physics?
Thanks for the AmA!


I don't think it holds us back. There are so many people going down so many different tracks, some down rabbit holes. Frankly, if you have a new idea, nobody takes it seriously if you can't test it.

I was looking at working there in the future!! So exciting to see someone like you from Australia on this subreddit, your work gives me hope for the future of Australian Astronomy and the instruments I'll hopefully get to use one day!


Hey, so much going on in Australia, and all very exciting. We've just joined the European Southern Observatory which is awesome! I think getting into the Eurovision song contest must have helped :) or not. Now if we could just drag the European landmass a little closer...

Do you believe there will ever be a method to travel faster than the speed of light? I know it is ridiculously fast but in the grand scheme of things it is so slow.


To be honest, I can't see how. Greg Benford's book talked about tachyons but no evidence to date...

What books, documentaries, websites, blogs, magazines, etc. would you recommend to people without any knowledge of astronomy but that would like to start learning about it?


On Amazon, I see many self-help books like Practical Astronomy which talk about buying a small telescope, and off you go. I think that's the very best way to start if you want to get your hands dirty. There are so many kit now. And join an amateur astronomy club. Do a websearch to find a good one.

What does your job mainly consist of


Meetings and helping people, 60% of my day. I have to hide away to "do science" but then I feel guilty if the emails mount up.

Do you think there's need for astrophilosophy as we move forward?


There are clever philosophers of science out there. See the book by Lewis and Barnes on the Anthropic Principle, also any book by John Barrow.

Can you please tell us who Hawthorn is from Destiny 2? What's the lore behind her? How did she survive so long outside the walls of the last safe city?


Absolutely no idea - those Hawthorns get around.

How often do people confuse you with an astrologer?


Yeah, from time to time. I always say I am a radio astrologer and if I hold my hands far apart, I improve the resolution.

How do you personally contribute to the conspiracy that hides the fact that the Earth is flat? Have you ever been to the edge?



I only know two-dimensional people. Oh, and graphene is 2D, awesome material predicted before it was observed. As for the Earth, beautifully round. Why not buy a flight on Virgin Galactica and see for yourself?

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