Like many at the Dunlap Institute, I share a firm belief that it is a key part of being an astronomer to communicate what we do with the public. Explaining science is a vital task in our increasingly technological world, and on a more personal level, I love astronomy and feel that when you’re in love you want to shout it from the rooftops. And it’s the same for finding effective techniques in science communication- over the years, as I have become increasingly involved in science outreach I have become curious how other astronomers around the globe do various outreach initiatives. So when I heard about the International Astronomical Union’s Communicating Astronomy conference, held every two years, I knew I wanted to attend! (The fact that it was in Japan during cherry blossom season didn’t hurt…)
This is the group picture for the 2018 CAP conference- about 450 people from 53 countries attended! It was wonderful to meet people from all over the world who love astronomy and want to share their love of the field with others, and to learn what methods work and what doesn’t. For example, we learned during a presentation on the 2017 total solar eclipse that it’s estimated that 20 million Americans traveled to see the eclipse… but many of those people did not travel all the way to the path of totality, despite totality being the most incredible part of the spectacle. Understanding what kind of miscommunication led to this (for example, were the eclipse maps misleading for what totality looked like?) is crucial for Toronto astronomers already preparing for the April 8, 2024 eclipse. In Toronto, 99% of the sun will be covered, and it will be important to explain to the public that even 1% is literally the difference between night and day!
Besides learning what others were up to, I had a talk of my own! Over the years, I have been active on Reddit, a social media website that is the 9th most visited in the world, as “Reddit’s astronomer.” I have become successful on Reddit for posting enthusiastic comments about astronomy that begin with a cheerful “astronomer here!” and can reach literally millions of people, but Reddit is under-utilized by many astronomers who tell me they don’t understand how the site works. The aim of my talk was to explain how to use the site for outreach, and the questions I had both after the talk and in the days after lead me to believe it was well-received and there will be more astronomy-related posts on Reddit in the future.
So all told, a wonderful conference with a beautiful backdrop with springtime in Japan! I learned a lot, and it was great to meet people from all over the world interested in communicating astronomy.
It’s about time I caught everyone up on my last couple of exciting weeks at the South Pole! Back in the first week of January, we finally achieved ‘first light’ with the upgraded South Pole Telescope camera, SPT-3G. This means we successfully installed the camera back onto the telescope, and the detectors were responding to the light from astronomical objects (such as planets and star-forming regions). Even though the camera is designed to measure light from the Big Bang, there are many other bright sources in the sky emitting microwaves that we can use to test our instrument.
It might not look like much, but this screen is showing live data from a handful of detectors on our first scan of an astronomical object. The sharp downward spikes correspond to light from a quasar, an active galactic nucleus over 5 billion light years away!
One of the primary goals of the South Pole Telescope is to measure light from the Cosmic Microwave Background (CMB); relic radiation from the Big Bang. The Universe began its life far denser and hotter than it is today, a primordial soup of light and particles. Almost 400 thousand years after the Big Bang as the universe expanded and cooled, this primordial light ceased interacting with particles and began to travel freely throughout the Universe. This is the light we see today as the Cosmic Microwave Background, providing us with a valuable tool for probing the conditions of the early Universe.
A brief history of the Universe. The Cosmic Microwave Background (CMB) light we measure using SPT is labelled in the diagram as the ‘Afterglow Light Pattern’. Image courtesy of: NASA/WMAP Science Team
Soon the camera will begin to survey a large patch of sky, measuring about 1500 square degrees (almost 4% of the entire sky). The goal of this survey is to map out tiny fluctuations in the CMB temperature, where these changes in temperature are smaller than 1 part in 100,000 (like measuring centimetre-high waves on a kilometre deep ocean). Thanks to the large 10-metre dish on the telescope, SPT-3G can map out these tiny fluctuations with high angular resolution, better than any other microwave telescope. This makes SPT well suited to particular science goals, such as measuring the gravitational lensing of CMB photons on small scales. This bending of light throughout cosmic history tells us a lot about the growth of structure in the Universe, where the growth of structure strongly depends on the mass of a fundamental particle called the neutrino.
An illustration showing how CMB photons are deflected by the gravitational lensing effect of massive cosmic structures as they travel across the Universe. Image courtesy of: ESA and the Planck Collaboration
The South Pole Telescope is also a powerful tool for locating galaxy clusters, some of the most massive gravitationally-bound objects in our Universe. Clusters of galaxies are so massive that they imprint a unique ‘shadow’ in the CMB, where CMB photons have been scattered off high-energy electrons inside the galaxy cluster. We can then begin to discover galaxy clusters by looking for these unique imprints in a map of the CMB, with SPT-3G allowing us to find smaller galaxy clusters than ever before using this method. We predict that SPT-3G will eventually be able to find over 3000 galaxy clusters, with many of those being previously undiscovered! As well as being fascinating objects to study in their own right, surveying the population of massive galaxy clusters throughout all of cosmic history provides another valuable insight into the growth structure in the Universe.
In a typical SPT map we can see signal from the CMB, point sources, and galaxy clusters. This infographic shows data from the SPT-SZ camera, first deployed in 2008. Image courtesy of: Bradford Benson
After we had raised the camera back inside the telescope, there was suddenly far less screw-turning that needed to be done. In its place, we started the long process of plugging back in the many different cables needed to operate the camera.
Following ‘first light’ in early January, we could finally begin to start looking at data to understand the properties of our upgraded camera. I spent my final week at the South Pole helping with the analysis of this initial data, until the day finally came with a flight that would take me away from this incredible place at the end of the world.
I flew out of the South Pole on January 17th with four other members of the SPT team, only five days after our scheduled departure. Reminiscent of my trip down, each day began with checking the flight schedule and engaging in wild speculation as to whether our flight home would actually arrive.
Although some of us were leaving, the arriving flight brought in several fresh SPT-ers to take our place and continue working on the telescope until the end of the summer season in mid-February. Following the last flight out of the station in mid-February, we then leave everything in the very capable hands of the SPT winter-overs, who will run and maintain the telescope in freezing 24-hour darkness until next Austral summer.
A photo from one of our winter-overs, Joshua Montgomery, showing the annual South Pole sunset at the end of March.
This time around I only spent a single night in McMurdo, before boarding our 9 hour-long LC-130 flight back to Christchurch. Landing around 11pm, I experienced nighttime for the first time in over 2 months! Funny that you can miss something as simple as the setting Sun.
Seeing as I was already on the bottom of the world, I was able to briefly visit my family back in Perth, Western Australia, before making the gruelling 54 hour journey back to Toronto. I have no idea if I actually slept during those five flights across four countries, but after almost 3 months away, there was no better feeling than finally getting home to my own bed.
It’s now been just over a month since I arrived back in Toronto, and have dived right in to developing the software we use to analyze the data being sent to us from the South Pole. There’s no question that my time at the South Pole getting hands-on experience with the instrument has already helped my work back here in Toronto. It is without a doubt a trip I will never forget, and I’m already crossing my fingers that one day I’ll get to venture back to the end of the world!
OBSERVATIONS 