Podcast: Strange objects at the centre of the galaxy, and improving measurements of online activity

Host: Benjamin Thompson

Welcome back to the Nature Podcast. This week, strange objects at the centre of the galaxy…

Host: Nick Howe

And rethinking how researchers measure screen time. I’m Nick Howe.

Host: Benjamin Thompson

And I’m Benjamin Thompson.

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Host: Nick Howe

Picture our galaxy… the Milky Way… vast arms spiralling away from a glowing core. And right in the middle of that core, in the galactic centre, there lies a black hole called Sagittarius A*. The galactic centre has been the focus of decades of study, as astronomers try to work out how the black hole interacts with the matter around it. How active is it? Is it growing? Now in Nature, a team from the University of California, Los Angeles have confirmed the existence of a population of strange objects orbiting Sagittarius A*. Noah Baker called up lead author Anna Ciurlo to find out more.

Interviewer: Noah Baker

You spend a lot of time gazing into the centre of our galaxy, looking in the region of the black hole that lives there.

Interviewee: Anna Ciurlo

Yes, it’s not just a black hole. It’s a supermassive black hole, so much more massive than regular black holes that have the mass of maybe a few times the mass of the Sun. This one is millions of times the mass of the Sun.

Interviewer: Noah Baker

And in this paper, you’re reporting this population of strange objects that are orbiting this supermassive black hole at the centre of our galaxy. Before we get into any more details, what is it that you’ve seen?

Interviewee: Anna Ciurlo

In general, around the black hole, there are many, many stars orbiting, but these objects that caught our eyes, actually, they’re pretty interesting because they are compact. They look like gas clouds but then they orbit the black hole like the rest of the stars. They stood out between all of this stuff that is in the galactic centre because they look like clouds but behave like stars, basically.

Interviewer: Noah Baker

How are you seeing these things? They’re incredibly far away and black holes are notoriously hard things to look at. What is it that you’re using to study these objects or to find these objects?

Interviewee: Anna Ciurlo

So, what we do is look in the infrared, more specifically in the near-infrared, and we use the Keck Observatory, which is one of the biggest telescopes in the world for near-infrared, and we use an instrument which is called OSIRIS, which is a spectro-imager. What does it mean? It means that basically, when you take an image of a field of view, for every pixel of your image, you also have a spectrum, so you create what is called a data cube. So, you have two spatial dimensions, x and y, and one wavelength dimension, so that’s why it’s called a data cube. And this is great because it not only gives you the information of the spatial distribution of whatever you want to study but it also gives you a corresponding spectrum, so you can study the emission line, you can study Doppler effect, the motion and the physics. So, what we saw were these very compact objects that were emitting in the gas emission line, so it’s an emission that is usually associated with a gas that is absorbing light and reemitting it, but since we studied this region for many, many years, we could see they orbit around the black hole. So, this is behaviour that is usually shown by stars because a gas cloud would get stretched, would get swallowed by the black hole, whereas a star is just orbiting the black hole.

Interviewer: Noah Baker

Do you have any idea what these things might be?

Interviewee: Anna Ciurlo

There are many scenarios that have been proposed because one of such objects was very famous in the past, called, G2, and so there was a lot of speculation of what it could be. We tried to apply these explanations to our now grown population of objects and we think that these objects are the product of the merger of a binary system. So, binary systems can be made by two stars that orbit each other and together orbit the black hole. So, what happens is that because of the presence of the black hole that has a very huge mass, these two stars that are orbiting each other are perturbed by the presence of the black hole and they get closer and closer to each other. They can start tipping the shell one from the other and eventually they can merge and form a new product. The thing is that doing this process, it’s kind of very messy. You have dust that is shed all over the place, you have gas that can be formed, and so you create kind of a cloak of material that can shield the newly formed star inside, and so this could correspond to what we see with these objects that show the emission of dust and gas and not the star because it’s probably just shielded inside of all these materials.

Interviewer: Noah Baker

Is this, at this point, still speculation or is this something that you’ve been able to model and work out is what is happening?

Interviewee: Anna Ciurlo

Yes and no. So, we compare with models of how many binaries would merge in the environment of the galactic centre and so on, and so the number of objects we find is consistent with the number of objects you would expect given the population, age and presence of the black hole and so on, so this kind of fits with the model. What we don’t have is how exactly the merger would happen because this is a kind of simulation that has never been done because it’s very complex and it would need a lot of calculation power that we don’t actually have.

Interviewer: Noah Baker

So, you’ve seen these objects – what’s next for you to find? Are there many other objects you expect that you might see over the coming years or do you have plenty left to study on the ones you already have?

Interviewee: Anna Ciurlo

Yes, so there are multiple things. If we believe these objects are the product of binary mergers, the number of objects we find is already kind of comparable with what we expect, so maybe that’s all we will find in that region, but what do we need to do? First of all is look at a slightly bigger region because we have been looking very close to the black hole, then what we should do is also look in for these types of objects somewhere else because this will help us test this hypothesis that this type of mechanism that is forming them happens primarily nearby a supermassive black hole.

Host: Nick Howe

That was Anna Ciurlo from UCLA in the US. You can read her paper over at nature.com.

Host: Benjamin Thompson

Later in the show, we’ll be hearing how human body temperatures might be declining, and that’s coming up in the News Chat. Now though, it’s time for the Research Highlights, read this week by Anna Nagle.

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Anna Nagle

Physicists might be known for their high-tech labs, but a team in the UK found that a seventeenth-century London landmark offered the perfect conditions for their research. The scientists wanted to measure nanoscale deformations in a long wire as it twisted, but they needed somewhere where they could hang a 50-metre wire where it wouldn’t be disturbed by air currents. They found the perfect location at the Monument – a 60-metre-tall column in central London built in 1670 to commemorate the Great Fire of London. It did mean the scientists had to conduct their research overnight though, when the attraction was closed to tourists. They hung their wire down the shaft of the Monument’s spiral staircase, then twisted and untwisted it before letting it come to rest. They found a slight permanent deformation in the wire, equivalent to less than 9 parts in a billion. This is one of the most precise measurements of its kind ever recorded. You can find that research in Review of Scientific Instruments.

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Anna Nagle

Generosity isn’t a widespread trait across the animal kingdom. Only certain apes have been found to deliberately help each other out for no reward, including orangutans, bonobos and at least some humans. Now, African grey parrots have joined the short list of helpful species. Researchers in Germany trained zoo parrots to pass a token through a hole in exchange for some tasty walnuts. They then placed two parrots in adjacent enclosures with a transfer hole between them. One bird had the walnut exchange hole but no tokens, while the other had tokens but a blocked walnut hole. The researchers found that the parrots with the blocked walnut hole spontaneously passed their tokens through the transfer hole to their partner. They wouldn’t personally benefit from the gesture, but their partner could enjoy a walnut. They didn’t bother passing the token when the neighbouring enclosure was empty, nor if the other parrot couldn’t exchange it for food, suggesting that the birds understood what they were doing. Reward yourself with that research over in Current Biology.

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Interviewer: Benjamin Thompson

Around the world, concerns are growing that our love of screens and the constant flow of information within them is having an effect on our health, and it seems that most of the stories you might see or hear suggest that it’s having a negative effect. Staring at screens is something I’ve become acutely aware of. I have a little baby back home, and I’m conscious that she’s become very interested in the phone screen I’ve caught myself listlessly scrolling through, which is not something that I want to encourage. But what effects are screens and digital media really having on our health and wellbeing? It’s tough to find any definitive evidence either way. This week in Nature, there’s a Comment article from a group of researchers who argue that the way that data on digital media consumption is gathered needs to be changed if we’re to more accurately understand its impacts. One of the Comment’s authors is Byron Reeves from Stanford University in the US. I gave him a call and started by asking him how people’s online lives are currently measured.

Interviewee: Byron Reeves

So, there are two choices if you’re doing research in this area. One is you can go into a laboratory, make a recording, design an experience that people might go through within the context of twenty or thirty minutes, you ask them questions and so this whole experimentation strategy is useful. The more interesting to most people is go out in the wild, try to figure out what people are actually doing in their normal lives, and this is where the problems really begin to occur because generally, the data across thousands of studies are questions to people about what they do with their time, like ‘Yesterday, how many hours did you spend on Facebook?’ or ‘This week, have you been a heavy or light user of your smartphone?’

Interviewer: Benjamin Thompson

And in your Comment, you highlight that this way of going about things might not be the best way of doing it.

Interviewee: Byron Reeves

It’s not the best way and we’ve been doing it a long time. We were doing it when there were only three television channels in the US and it was even difficult to do then. But think of all the things that you do just even on a smartphone device, and we’re in and out of these devices hundreds of times in an average day.

Interviewer: Benjamin Thompson

Why do you think a different method is needed to measure what people are doing on their devices?

Interviewee: Byron Reeves

If we don’t do something more granular, we’re just not going to know what people are doing in relation to the concerns that we have. So, you can name any one of these concerns. If it’s processing of news in a politician campaign or experiencing Facebook with respect to my psychological wellbeing, we can know about your wellbeing and we can know about your politics but we can’t know about what you’re doing in media in relation to those concerns without doing something like we’re proposing with the Screenome Project.

Interviewer: Benjamin Thompson

So, your Screenome Project, it hasn’t been going that long. What sort of data are you collecting and where are you planning to take it?

Interviewee: Byron Reeves

Well, we started this about three years ago. We started developing technology that we could put on people’s devices and that would allow us to unobtrusively collect a screenshot every five seconds to encrypt it, compress it, send it back to Stanford research servers and allow us to get a computer to try to analyse what they’re doing. We’ve collected about 30 million of these screenshots, and we’re trying to figure out how to do the computerised analysis of what’s in these screens from many different kinds of categories and classifications.

Interviewer: Benjamin Thompson

The way people use their phones is quite personal in many cases. Are you struggling to find people to sign up to your project? Is there any reticence at all?

Interviewee: Byron Reeves

Well, there is some reticence and there is a great deal of interest, even among those that do sign up, in exactly what we’re going to do with these data. We’re never sharing these data. We’re going through consent procedures that tell them exactly how the data will be collected and stored. We have institutional review boards that look very closely at our research. It’s vetted by privacy attorneys and cybersecurity folks. I think we find, increasingly, people are getting used to the fact that the companies that are building the products that they use are getting these data anyway in some fashion, and so they’re interested in participating in the university research project that helps.

Interviewer: Benjamin Thompson

Broadly speaking then, what sort of questions might this very granular approach to data collection help to address that maybe other collection methods have struggled with?

Interviewee: Byron Reeves

Yeah, so the questions in the past have really been about large chunks of experience, so ‘How much did you use your smartphone last week?’ What possible effects could there be versus going in and taking a look at exactly what you were doing. If you were turning your phone on and off 500 times a day to get a quick hit of excitement, looking at a post or something, doing whatever you are in these small little chunks of experience, that’s a very different kind of an effect. That actually might be more interestingly related to something like psychological addiction than information about general use over the course of long periods of time. So, you get different questions when you’re able to get a better microscope than can zoom in.

Interviewer: Benjamin Thompson

Is there the concern though that maybe with the amount of data that projects like these are able to encapsulate and to record, if there’s such granularity between people, that maybe we run the risk of missing the wood for the trees and it becomes difficult for policymakers or public health officials to make broad policies on usage and what have you?

Interviewee: Byron Reeves

Yeah, that’s a good question. We’ve got a real problem with respect to your question because the answer is that a lot of the use of this technology is quite idiosyncratic, and as researchers and just as anybody commenting on these problems, our tendency or our desire is to try to abstract something we can say about everybody and really look at these cross-sectional or sub-group averages. What we’re finding though is that there’s so much content and so much you can do with these devices that really is, when you think about it, it’s not that unlikely that people would have very different routes through all that information, and that’s what we find when you actually look at the screenomes for these records of moment by moment changes, that people really do have different content that they’re interested in, they have different paces, different rhythms, and of course, while our interest is to try to say something that can be abstracted for large groups of people but I think one of the lead stories so far is that everybody is really different.

Interviewer: Benjamin Thompson

Well, you’ve collected a huge amount of data already, and what has surprised you about how people use their devices or how they look at screens?

Interviewee: Byron Reeves

What surprises us most is, when you just sit there in the research lab and go frame by frame through a smartphone day for an individual, how much different kinds of content are tangled together in short bursts of use, in ways that we never could have anticipated, so this is the most surprising thing. You find somebody on their smartphone, one of the tabs is a video conference for a work group, you quickly go out of that and send a text message to a spouse or a kid, you check the news and the sports, you might look at pornography, you might do something that you shouldn’t be doing, but you’re quickly going in and out of all these radically different forms of content. All these things are just getting a chance to influence each other within a relatively small amount of time.

Interviewer: Benjamin Thompson

Having seen these data then, do you think it’s affected how you’ve used your devices and things like that? Has it changed your behaviour in any way?

Interviewee: Byron Reeves

Yes, all of us. There are a dozen of us in the lab that talk about how it’s affected our own uses. First of all, it’s made us realise that we’re not that different from the people that we’re looking at, that when we’re working on the screen, writing a paper, we’re spending two or three minutes writing a great couple of sentences, then checking the news and checking a Facebook post, and then back in ten seconds for the next paragraph and a little bit more excited or a little less bored, and just realised that these are interesting threads that we’re able to piece together now that we never had the opportunity to do.

Interviewer: Benjamin Thompson

That was Byron Reeves. You can read his Comment article over at nature.com/news.

Interviewer: Nick Howe

Finally, on this week’s show, it’s time for the News Chat and I’m joined in the studio by Nisha Gaind, Nature’s European Bureau Chief. Nisha, hi.

Interviewee: Nisha Gaind

Hi, Nick.

Interviewer: Nick Howe

Thanks for joining me. So, as always on the News Chat, we’ve got two stories this week and for our first, there’s a report that human body temperatures are declining.

Interviewee: Nisha Gaind

Yeah, that’s right. We have got a story on a really interesting study that has looked at lots of data, including data that goes back all the way to the nineteenth century, and it has concluded that bodies are getting colder than the textbook figure of 37 °C.

Interviewer: Nick Howe

And that’s a figure everyone knows – 37 °C – but how did we get to that in the first place?

Interviewee: Nisha Gaind

Yeah, that’s right, and there’s a little bit of a story around this 37 °C figure as well because it’s not totally accurate. It’s a number that was determined in 1851 by a German physician and he took millions of measurements and decided that normal body temperature was 37 °C but of course, thermometers were rather different then, they were rudimentary, and several studies since have determined that bodies are probably a bit cooler than that.

Interviewer: Nick Howe

So, there’s obviously been a bit of a measurement issue and things have got more accurate over time, but this new study is suggesting that despite that, body temperatures do really seem to be declining.

Interviewee: Nisha Gaind

Yeah, that’s right, so the authors address this issue of measurement. They look at three different datasets. One of them is really old and interesting – it’s from veterans of the American Civil War – and then the later datasets are from the 1970s and roughly the past decade. And so, to address this issue of measurement error, the researchers looked within this Civil War data and they found that people who were born in earlier years tended to have higher temperatures than those that were born in later years, even when their body temperatures were measured in the same year and probably with the same technology, so they say that that suggests that improvements in thermometer technology aren’t the reason for this declining trend, and the researchers say that they show quite clearly that over these decades, body temperature has dropped and they determine that it has dropped by about 0.03 °C per decade.

Interviewer: Nick Howe

Do they have any ideas why the temperatures might be declining?

Interviewee: Nisha Gaind

Yes, so the reason that they put forward is that in the olden days, in the nineteenth century, people were living with much higher rates of chronic disease. They were living with things like tuberculosis and gum disease and these are things that provoke inflammatory responses that tend to elevate cool body temperature and because of progression in medicine and society, those sorts of chronic diseases are much less common these days, so that’s the reason that they say that bodies are likely to be cooler now than they were 150 years ago.

Interviewer: Nick Howe

So, is this now resolved? Do we know what body temperature is? Do we have a new textbook figure?

Interviewee: Nisha Gaind

So, this study hasn’t necessarily put forward a fresh figure for what body temperature is. We can draw on these previous large studies that say it’s around 36.6 °C. But it’s more just this interesting sort of idea that they have slowly been decreasing over the centuries and probably could continue to decrease.

Interviewer: Nick Howe

But I understand that not everyone is convinced by this study’s explanation.

Interviewee: Nisha Gaind

Yes, of course there are detractors that say they aren’t quite convinced by this result. One says that there are many variables that are unaccounted for. For example, in this Civil War data, it’s not noted whether the temperature was taken orally or in the armpit and that that is something that could affect the results. But the authors of the study, they counter that people have changed over the centuries. We’ve gotten taller, we’ve become fatter and these are all things that could affect temperature.

Interviewer: Nick Howe

So, we’ll have to take the temperature of this research in the future and see if we’ve got a new textbook answer to body temperature. But for our next story, this is actually something that we talk about a fair amount – research culture – the environment scientists live and work in, and there have been several surveys and reports that have painted this environment in a pretty poor light, and now the Wellcome Trust have done their own. What can you tell me about this latest survey, Nisha?

Interviewee: Nisha Gaind

Yeah, that’s right. It’s something that we’re reporting on very regularly because there are, frankly, a lot of reports from scientists around the world that say that research culture is something that is becoming increasingly difficult to do work in, and that is a feeling that is reinforced by this large survey that has been done by the Wellcome Trust that, frankly, paints a damning picture and it says that this environment that scientists work in and are producing science is highly competitive, it’s often aggressive and that all of this is something that is damaging the quality of science.

Interviewer: Nick Howe

So, what explicitly are scientists’ concerns that have been raised in this?

Interviewee: Nisha Gaind

So, this is a really broad survey that spoke to 4,000 researchers done by the Wellcome Trust, which is a massive funder of research around the world, and the findings that they present are unfortunately quite familiar things that we’ve heard from researchers in other surveys, as you say. It’s things like high pressure, long hours, a lack of job security and often reports of poor mental health, anxiety, depression, harassment, bullying, so quite serious issues that are being presented by large proportions of researchers. And there’s another big issue that researchers talk about and it’s this dominance of metrics and performance indicators, things like the impact factor of the journals that they publish in, that they say funders and institutes put a huge amount of emphasis on in a way that reduces morale.

Interviewer: Nick Howe

And as you alluded to there, scientists have actually reported having mental health issues as a result of these pressures.

Interviewee: Nisha Gaind

Yes, that’s right. Half of these respondents say that they have either wanted to or have actively sought help for anxiety and depression, and that’s a really huge proportion of researchers and it’s something that we know chimes with our readers when we write about this. We get a large response from readers and listeners, so it’s a big issue that is coming to light in the research community.

Interviewer: Nick Howe

And is Wellcome responding in any way to these results?

Interviewee: Nisha Gaind

Yes, that’s right. This is a survey that’s been done by Wellcome, but we should be clear that this isn’t something that applies only to Wellcome researchers. The survey spoke to thousands of researchers across the world, but it is part of a broader initiative by Wellcome which they launched last year and it’s called reimagining research, and they’re looking for ways to make the research enterprise essentially less damaging. There have been so many reports of this hypercompetitive environment and toxic power dynamics and they’re looking for a way to reframe that, so this is a survey that will help them to do that. It will help them to develop ways in which they hope to change the research culture and they will be looking to develop a plan of action in the next few months by talking to researchers, talking to universities and discussing the issues that have been raised by this survey.

Interviewer: Nick Howe

Right, well this is obviously a pervasive problem but hopefully we are starting to work towards solutions. Thank you so much for joining me, Nisha.

Interviewee: Nisha Gaind

Thank you.

Interviewer: Nick Howe

And listeners, for more on those stories, head over to nature.com/news.

Host: Benjamin Thompson

That’s all we’ve got time for this week. If you’d like to get in contact with us, why not send us a tweet? We’re @NaturePodcast. Alternatively, send us an email at podcast@nature.com. And just before we go, we’ve had a few people ask if we have transcripts available for each show. The answer to that is yes. You can find them attached to each episode over at nature.com/podcast. They’re usually up by the Friday of each week, and thanks go out to Becca, our Editorial Assistant, who writes them. I’m Benjamin Thompson.

Host: Nick Howe

And I’m Nick Howe. See you next time.