Daily Maverick Interview: The Hitchhiker’s Guide to the Galaxies
- Marelise van der Merwe
- Life, etc
- 17 Mar 2017 12:05 (South Africa)
Are we about to be sucked into a black hole? Can we start packing our bags to live on another planet? (Tempting.) If it’s not a planet and it’s not a star, what is it? Are we going to send humans to Mars by 2030? Knowledge of astronomy, like most sciences, is increasing exponentially, and it can be hard to keep up. MARELISE VAN DER MERWE asked astronomer Dr Anja Schroeder for a tour.
Last year, after several hidden galaxies were discovered behind the Milky Way, Professor Renee Kraan-Korteweg told Daily Maverick: “We are like explorers of the universe.” But beyond a general sense of wonder, the average Joe’s understanding of this remains limited. Astronomer Dr Anja Schroeder says there’s not always an overlap between a catchy headline and a significant discovery. Despite growing media coverage, we’re still somewhat in the dark.
That’s not to say there’s no interest: recent news, for instance, includes investigation of a baffling rogue planet-like object; not one, but seven Earth-sized planets found orbiting a tiny star quite nearby. In between, there’s the ongoing hunt for exomoons and the chance that Nasa and other International Space Station partners could begin construction on an orbiting lunar outpost as early as the 2020s. Not to mention leaps and bounds in the study of gravitational waves.
Dr Schroeder is Honorary Research Associate and SALT Commissioner at the South African Astronomical Observatory. Her field is the galaxies that lie behind the Milky Way (she was on the team that made the abovementioned discovery in 2016) and she’s a support scientist for the MeerKAT project. She gave Daily Maverick a hitchhiker’s guide to the galaxies, plural.
DM: What would you say are the most important astronomy-related discoveries in recent years?
It’s hard to give a complete answer. But here are some: the discovery of exoplanets (I still remember people speculating about planets and being sure we’ll never find any). The discovery of the accelerated expansion of the universe and Dark Energy. And most importantly, since it’s very recent: the discovery of gravitational waves. I’m sure there is a Nobel Prize in it.
DM: What’s the gap between what scholars view as important, and what typically makes headlines?
Headlines are usually simplified and more “black-and-white”, for example the discovery of a new object, while we scholars know that those objects are out there and have indications of that, but haven’t been able to really prove it. So the emphasis is different.
But there are also new developments or discoveries that don’t make the news, because they are gradual, or it simply is not exciting enough or understandable enough for the public, or the scientists haven’t thought of putting out a press release. For instance, I personally didn’t think our work on the hidden galaxies was worth a press release... it’s an ongoing project and much work has already been done in this area.
DM: What, in your ideal world, would grab enormous media attention?
I think gravitational waves is really a good example. It excites every scientist since it is so new and so long-awaited. For niche astronomy press I would wish for something similar: the reporting of something truly new or finally confirmed. There are so many articles out there that add only a small piece of the puzzle to the overall picture. Don’t get me wrong, these are all important, even if, or because, they are wrong or contradict other research.
Regarding our “hidden galaxies”: There are galaxies all around us. We only found a handful, though they are difficult to find. We used a new method to look for them, but that method was simultaneously used to observe the whole sky, not only the Galactic Plane.
Don’t get me wrong, I like that the public does find this newsworthy and that the press can communicate how exciting science can be. I find this greatly important, it is what we really need. Otherwise the scientist may be seen as some half-crazy recluse or someone who has a great time without doing any “real” work, only bickering amongst themselves!
DM: Last month the discovery of seven roughly earth-sized planets orbiting the dwarf star Trappist-1 was announced. How likely is it that we will find more, similar planetary systems nearby?
Quite likely. The estimate is that most stars have planets, and to only have a single planet would be unusual. Most theories assume a cloud of gas and dust that forms a disk around the new star, and that disk will fragment in several clumps which then built planets. The disk is too large in radius to form only a single star; it has to fragment.
The fact that so far we only know of “single” planets around a given star lies in that we only find the largest and innermost planets. The James Webb telescope (JWST), for example, will improve the sensitivity so that we can find fainter planets. The Large Synoptic Survey Telescope (LSST) will do a long-term, large-area survey which will also catch planets at larger orbits, which move more slowly and can therefore only be found if we observe those stars for decades!
DM: The discovery of other planets, orbiting stars other than our sun, only really started in recent decades. What kind of discoveries can we anticipate in coming years?
We will start finding smaller planets and more planets per system. That’s a continuing process. The real excitement will be to observe atmospheres of those planets. Because, if we are lucky, the atmosphere could tell us about life on those planets.
The South African Large Telescope (SALT) will participate in the exoplanet hunt with the new high-resolution spectrograph. I don’t think MeerKAT or SKA will help much in this respect. It will be up to individual scientists to join groups that use the new instruments like JWST or LSST to study exoplanets.
DM: A great deal of noise has been made about the seven ‘new’ planets possibly being life-sustaining. Should researchers find a definitive answer, what follows?
I don’t think researchers can be stopped finding out something like this if the means are there to do it. Neither do I see any ethical reason not to in this case, as there would be, for example, in medical research.
As to the effect? We would prove that there is other life in the universe – immensely exciting! I’m not sure how long it will take us to find out what kind of life it could be: single cell creatures, higher life forms, or even intelligence, if we ever are able to tell something like that.
There is, of course, also SETI: if we find another life form that communicates through electromagnetic radiation, that is incredibly exciting. There is always the concern about possible animosity, but one thing we can rely on is that space travel will be much, much slower than light travels, so anything further than a few tens of light years will never concern us “in flesh”.
DM: What are the most important elements driving astronomy forward?
Certainly new, bigger telescopes, especially satellite telescopes. New detectors, with a larger field of view, smaller pixels, and more sensitive. And adaptive optics, to get sharper images.
Funding is also important, not least to make available permanent positions. People waste too much time looking for the next job, getting used to a new position and therefore working less efficiently. Less time is spent on actual research.
But software is really the new kid in town in astronomy. With bigger telescopes, more data, higher data rates, we not only need faster computers and more storage, we need the algorithms to reduce the data in an automated way. Doing it by hand improves the quality, but it simply takes too long. Automation is not easy; it needs careful quality control in other ways than through the human eye.
We also need ways to mine the data and store it efficiently so that we can search what we are looking for. The future of astronomy lies in Big Data. We need new computational methods: compression of data for better storage; efficient searching and mining of data; real-time data reduction (ASKAP in Australia produces data cubes that no software today can handle, so they need to “degrade” the data); simulations based on finer and finer resolutions – and that is the only way we can make reliable predictions close to the regime of mathematical chaos.
Software development is still an undervalued job, as people don’t understand that (a) it takes a scientifically educated mind to do the software writing, and (b) it takes time to write good code.
DM: The JWST has attracted a great deal of media attention, including its potential to understand the formation of supermassive black holes. Why is this so significant?
It’s important because they seem to have a large impact on the star formation rate in galaxies, especially in the past when the star formation rate was so much higher. Many new instruments and projects are being built to understand star formation, starting from how a star is born (in our galaxy) to how stars looked at the beginning of the universe, to how a galaxy needs to be formed to produce stars and continue producing stars, to what triggers star formation.
DM: In the search for exoplanets, CFBDSIR 2149-0403 came up as a question mark: either a brown dwarf, a massive planet, or something else entirely. Do we have any idea what the ‘something else’ might be?
This is an example of the infamous “unknown unknown”; that is, we do not know what else is out there. And because we don’t know, we don’t know how to look for it. A famous example is the discovery of pulsars: there were regular “noise” spikes in the data. Ignored by most, since it didn’t fit in with known objects and seemed man-made. Yet Jocelyn Bell persevered to find out what really caused it and found a new class of astronomical objects that no one had thought of before. Quasars are another example. Every astronomer dreams of making such a discovery.
DM: Why are free-floating planetary mass objects [such as CFBDSIR 2149-0403] of such interest?
They tell us about how long such a small object can “survive” in space before it is recaptured by another star. They tell us about violent mechanisms that eject such planets – likely to be rare events, so whatever data we can find about such events will help enormously to understand and define them better; some events we could think of may not happen at all. They also tell us about how much mass there might be in the galaxy that is not luminous (that is, dark).
DM: What’s the biggest question you’d love to have answered in your lifetime?
I already got one, I think: they finally found gravitational waves. It is an entirely new astronomy, since all other data we have is based on electromagnetic radiation. This is a first, and I’m quite pleased to live in this time.
Another big question is Dark Matter. (Of course, there is Dark Energy as well, but it seems to me less important or less close to home.) What kind of particle or particles is it? Is it already postulated in physics or something new?
Another question: in high energy physics, what is there beyond the Standard Model? Strings and supersymmetry and such: which one will it be?
Finally, finding signs of life, be it through oxygen in other planets’ atmospheres, or more directly here in our solar system, e.g., deep underground on Mars, Titan, or Europa. DM
This interview was edited for brevity.
Photo: A handout photo made available by European Southern Observatory, ESO, on 08 March 2017, showing an artist's impression what the very distant young galaxy A2744_YD4 might look like. Observations using ALMA have shown that this galaxy, seen when the Universe was just 4 per cent of its current age, is rich in dust. Such dust was produced by an earlier generation of stars and these observations provide insights into the birth and explosive deaths of the very first stars in the Universe. EPA
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