Our timeless companion: Michelle Thaller's starry eyed gaze

Otago Daily Times

9 hours ago

Astrophysicist Dr Michelle Thaller has spent a lifetime with her head in the stars, she tells Paul Gorman.
In a world where terrible things are happening, a reminder we are inconsequential motes on the scale of the universe can be somewhat comforting.
''For you are dust, and to dust you shall return'', the sage words from The Book of Genesis say.
The same message is coming from one of Nasa's top scientists, astrophysicist Dr Michelle Thaller, who arrived in Dunedin at Matariki to be the special guest at this week's New Zealand International Science Festival.
''I've been wanting to spend a good amount of time in New Zealand for decades,'' she says.
''When it comes to celebrating Matariki, the idea that we come from the stars and we will go back to the stars, this is literally true.''
Recently retired after 27 years at Nasa, she will be sharing her knowledge of space and the universe at several festival events.
Thaller has specialised in the evolution of binary-star systems and is one of the world's top science communicators.
She sees the universe as a wondrous place, not something to fear because its stupendous vastness makes it cold and frightening.
''For me it's a bit more of a thrill than a fear. You know, the reason you get on a roller coaster is that sort of pleasant type of fear - you can play with the emotions: 'I'm afraid of this, but it's going to be OK'.
''But the interesting thing for me is that, and I don't know why, but the night sky has always seemed like an old friend, and I've met people all over the world who feel that way.''
While the universe has no emotional state to it, she says astronomy is not the study of ''something far away and dark and uncaring''. It is where we come from.
''There's nothing that makes the atoms of our bodies other than the stars - carbon and calcium and all of that - and the only place you have natural nuclear fusion is inside the core of a star, and you build up the atoms into bigger and bigger atoms.
''Then there's some of the things that our body needs, like iodine. Our bodies would not work without some of those trace elements, and the only time we've ever seen those trace elements made is with pulsars, these neutron stars, in unimaginably huge explosions.''
Thaller's Nasa career began at the Jet Propulsion Laboratory (JPL) in California as a senior scientist after graduating with her doctorate from Georgia State University and carrying out postdoctoral research at the California Institute of Technology (Caltech).
In 2009, she moved to the Goddard Space Flight Center in Maryland and ultimately became the assistant director of science there. She also did a three-year stint at Nasa headquarters in Washington DC.
While at JPL she became interested in science communication and was heavily involved in live Nasa broadcasts and also as a spokesperson on television programmes including How The Universe Works , and on news stories.
Her resume lists two Webby awards highlighting Nasa's social media programme among her achievements, as well as this year's accolade of Nasa's Exceptional Achievement Medal, which has previously been won by late astronomer Carl Sagan and the Apollo mission astronauts.
She is an adjunct professor at the University of Wisconsin and also works with the Smithsonian Institution on adult education and travel programmes.
Hailing from Waukesha, Wisconsin, Thaller says her love of astronomy began before she can even remember, about the age of 2.
''Mum said it was as soon as I could walk. She was like, 'kid, why do you care about the little lights in the sky?'. It became kind of a running joke.
''I've tried to get her interested in astronomy. She'd ask, 'well what causes the Moon phases', and as a little kid I'd get flashlights out and balls, and she's just like, 'I don't really care, I'm sorry'.
''But I just loved the stars. I was fascinated by them.''
She went to Harvard University to take her undergraduate degree in astrophysics, but found it challenging and initially intimidating.
''I was the first person in my town ever to go to Harvard. I'm from a small, rural community. That was a surprise to everybody, including me, that I got in. Harvard made it possible for me to come, with a combination of loans and scholarships and work-study programmes.
''In high school I was still doing pretty well in science classes, but then when I hit college, I was just struggling the whole time. I felt very lost, very confused.
''The professors meant well, but at that time, back in the late '80s-early '90s, you brought your notebook to class and literally wrote down what the professor was doing on the blackboard. And that was all you did. Then you went home to your dorm room.
''People have different ways of learning. And science in the past was taught, I think, in a very linear, kind of intimidating way. You know, like 'Do you have what it takes to study astrophysics?'.
''You know, if you can study anything, you can study astrophysics. It's like any other topic - I mean, how do you study enough to become a lawyer or a doctor?''
Through ''pure pig-headedness'' she stuck it out.
''I just loved astronomy, so I stayed there and suffered through it. About midway through my college career, I started to do research projects with the professors as part of my coursework and then things just lit up, because it was the practical application of these things.
''Say we want to observe these monsters called neutron stars. What sort of data do we need to take? How do we analyse the data? All of a sudden, it's your own exploration and your own questions, and working with other people.''
That carried on when she worked on her doctorate.
''A lot of people are worried that if they want to do a doctorate they have to come up with a brilliant idea all on their own. But no, you start working with a team of astronomers; you usually have one adviser, that's a professor, and they get you started on something.
''They might say, 'hey, look at this data that I have. Why don't you just start with that, and we'll talk about what you're seeing', and so you became part of a wonderful team.''
Had she ever wanted to be an astronaut?
''When I was young, yes. I went to space camp, which was run by the US Space and Rocket Centre, and I loved it. I loved astronaut training, and I had pictures of astronauts on my wall as a kid.
''And I got interested in the science behind the stars a little bit more than the actual going-to-space part of it. But I have a lot of astronaut friends, and some of the astronauts hopefully on the next Artemis missions, they're friends of mine.
''To put it kind of honestly, you know, as I got into college and grad school, I developed a fear of flying. So, you know, probably not the best thing for an astronaut to be afraid of.
''I still fly everywhere, I fly all over the world, but I'm getting better, but I'm not real comfortable in a plane. It gives me fear, especially turbulence where we bounce around. I understand everything about it, I mean turbulence isn't dangerous, but I'm getting much more calmed down about it.''
Thaller carried out much of her doctoral research on massive binary stars at the Mount Stromlo Observatory in Australia.
''These stars that are orbiting each other are sometimes 30 to 50 times the mass of the Sun. There's more of them in the southern sky than there are in the northern sky, because the centre of the galaxy appears higher in the sky in the southern sky than it does in the north, so there are actually more stars in the southern sky.
''These stars are not necessarily physically all that much bigger than the Sun, but the big thing is their mass. They have a very strong wind of particles coming off them, like winds of hot hydrogen gas, so they actually slam together a lot of molecules.
''The stars produce all of the atoms that we know but then, in these shock waves, in the winds of stars, you can get things like water molecules produced. In one of the systems I was studying, the shock wave of the winds between the stars produced enough water to fill Earth's oceans 60 times a day.
''It's making very hot, very gaseous, water, very diffuse gas, and that gets fed into the dust between the stars as we travel around the galaxy at about 700,000kmh. In the course of Earth's history, we've been around the whole galaxy about 20 times.''
Astronomers now have a sample of Asteroid Bennu, which shows how water reacted with the minerals, she says.
''It must have been part of a dwarf planet that got broken up at some point. But there was liquid water around, dissolving the minerals, which is amazing.''
Pulsars, the dead cores of stars that spin fast and emit regular bursts of electromagnetic radiation, also fascinate Thaller.
''There are some that spin a couple of hundred times a second. These are only about 30km across but with the mass of twice the Sun. That actually turns out to be twice the density of an atomic nucleus - it's the densest matter that we know of. So, pulsars are incredible monsters.
''There was an event in 2008 where there was a burst of high-energy radiation and a noticeable amount of atmosphere got blown up into space. And our magnetic field was ringing like a bell. And we were like, 'OK, what just happened?'.
''We traced it back to a little glitch - one of the pulsars had a tiny, tiny little change in the rate it was rotating. That pulsar was 50,000 light years away - a light year being about 10 trillion kilometres. We think there was a tiny shift in the crust of the pulsar, maybe about 1cm or less, and in a millisecond that produced more energy than the Sun puts out in a quarter billion years.
''We got a glancing blow of high-energy radiation from that thing. Some people wonder if such events might actually limit the lifetimes of civilisations. I mean, there are thousands, millions of pulsars all around us.
''One little bad day on a pulsar, and it takes out planets for light years.''
That potential threat to our existence is larger than from an asteroid, she says.
''The huge asteroid that took out the dinosaurs, it may have caused a huge shift in our climate but life survived that. But if you get a direct hit by one of these gamma-ray bursts, it can just strafe the atmosphere off.''
We're back to the returning-to-the-stars narrative.
On a brighter note, Thaller says she has had a great visit so far.
Her Ōtepoti experience kicked off with a train trip through the Taieri Gorge on a Stargazer journey operated by Dunedin Railways, Tūhura Otago Museum and the Dunedin Astronomical Society.
The events allow passengers to alight at Hindon and view the universe through up-to-date telescopes in a streetlight-free area.
''I've never done anything like it,'' she says.
''This was such a unique astronomy experience. A lovely historic train took off from the station, we were served a good meal on board, and in about an hour we got to a site that had telescopes and other activities set up. The young people running the show were just wonderful - full of knowledge and energy.
''We lucked out - there were patchy clouds around, but the holes were big enough to get good views of star clusters. Mulled wine and hot chocolate on the way back, and I answered astronomy questions over the train intercom.''
For an astronomer, that sounds like a heavenly cocktail. The festival
Expect the usual eclectic mixture of workshops, talks, tours and shows over the week, as more than 100 organised events are held across Dunedin until the festival closes next Sunday.
A random dive into the festival programme reveals events including: ''An Introvert's Guide to Extroverts'', ''A Flying Photon'', ''Atomically Correct'' (a quantum comedy), ''Coastal Parasites: The good, the bad and the ugly'', ''Death in the Distillery: A Forensic Mystery'', ''Exploring Dunedin's Extinct Volcano'', ''Heart Science for Kids'', ''Jean Stevens and 'Blooming Impossible', ''Living Alongside Pakake'', ''The Science Behind Everyday Appliances'', ''Te Tahu-Nui-ā-Rangi (Aurora) clay tile making'', and ''Fight Like a Physicist''.
• Check out the full listings at scifest.org.nz/