Categorising Galaxies with Galaxy Zoo

We speak to the team behind one of the oldest citizen science projects - Galaxy Zoo
23 September 2013

Interview with 

Karen Masters, Galaxy Zoo


Dominic -   One of the biggest and first established of these Citizen Science projects was the astronomy website, 'Galaxy Zoo'.  So, I caught up with Karen Masters from the University of Portsmouth who is the Project Scientist for this site.

 Karen -   Galaxy Zoo is basically a website.  It's a place where you can go and Spiral galaxylook at images of galaxies that have been taken in large astronomical surveys.  It shows a picture of the galaxy and asked a series of simple questions about what you see and you enter that information.  Then the galaxy, the science team and those of us behind the site take those information.  We collect typically 20 to 40 answers for each image and we used that information to figure out what is the most likeliest thing that that galaxy looks like, the most likely type of galaxy that that is.  And that's a piece of information we can use to study galaxy evolution to try to understand how galaxies fit into the universe, how they change and evolve, where they came from.

 Dominic -   Now, we hear a lot about very sophisticated computer algorithms for recognising features and images.  Are your volunteers really better than what computers could do?

 Karen -   Actually, yes they are.  Billions of years of evolution have made humans extremely good at pattern recognition.  It is extremely hard to teach a computer to recognise the kinds of patterns that humans recognise every day.  It's not to say that computers might not catch up, but in fact, the galaxy zoo information has been used already and is continuing to be used to help train computers get better at classifying galaxies.  But right now, there's really nothing that is as good as a person looking at a picture and saying, "That's what I see."

 Dominic -   I suppose the first challenge you faced when you set this up must've been finding a big pool of volunteers to give you this data.  How did you go about finding people?

 Karen -   We initially started with a million flow of images.  And the thought was that, if we put up those million images, we might get a few thousand people interested and eventually, over a period of a few years, you'd get one classification per galaxy.  With the launch of this site, this was in 2007 and it was big news then to launch a citizen science website.  And so, the news that this site was going live.  It was covered on the BBC website and it was immensely popular immediately.  In fact, it surpassed everyone's expectations.  Those 1 million galaxies were classified 40 times over in 18 months.  It sort of got to a point where we had these 40 classifications of the galaxy.  It sounds like overkill, but we've learned that that's extremely helpful because that allows us to use those information to work out, not only the most likely type of  galaxy, but how likely, and how confident people are.  Because if everyone says the same thing, it's obviously easy.  But if there's some disagreement, that's a piece of information we can use to measure how confident we are in the classification.

 Dominic -   You said you got the initial boost from the BBC website.  How many users are now involved in Galaxy Zoo?

 Karen -   Well, Galaxy Zoo, because it was so successful, it inspired the creation of something that became called The Zooniverse.  Zooniverse is the collection of similar projects.  So, the things they have in common are, that they show data to people over the internet.  That's either images or audio or movies.  Some kind of data where humans are better at extracting information from that data than a computer would be.  So, there's a whole variety of different universe project is not only astronomy now but also looking at animals in the Serengeti.  To classify in any of those projects, you now become a member of the Zooniverse and there are over 860,000 people who sign up for an account at the Zooniverse.

 Dominic -   So, that's quite an incredible army of volunteers you've got there.  How did you pick all of these projects for Zooniverse?  Do academics come to you and say, "I've got this research problem.  Could you ask your army to help with it?"

 Karen -   Yeah, that's exactly right.  The Zooniverse has sort of an ethos for what makes a good Zooniverse project.  There's a proposal system now.  It's a funded project.  So, it's proposal system for researchers to come in and suggest good projects.  We're also always sort of on the lookout for things that sound like they could be cool.  There was a new one launched just this week, looking at images of plankton from under the water.  I mean, the common factor of all of these zooniverse projects and the ethos is that, these are projects that have a real science question behind them.  So, you're doing real science online, you're contributing to threal science.  So, it's data or information that is not easy to process with a computer, can't be looked at by a small research team, but by involving hundreds of thousands of citizen scientists, we can actually answer a research question you couldn't answer any other way.

 Dominic -   What to your mind are the real highlights that's come out of the science of the Zooniverse over the last 5 years?

Karen -   For me, I've been very excited in how galaxy zooo helps us to find interesting samples of rare galaxies.  So, the two basic kinds of galaxies are spiral galaxies and elliptical galaxies.  The standard picture is that the spirals are blue and the elliptical is red.  What Galaxy Zoo has found is really interesting, small but large enough to do studies on, samples of blue ellipticals and red spirals.  And they might sound like just intriguing curiosities, but they're not.  They actually tell us about evolutionary processes, about how spirals might be turning into ellipticals and how star formations can be turning off in these galaxies.  And so, Galaxy Zoo, by providing such large samples that you can find small numbers, it has been a hugely amazing resource.

 Dominic -   Thanks to Karen Masters from Galaxy Zoo.  Of course, you can contribute to those projects on or  I think what I find really inspiring about these projects is that they've been so successful that made research papers where people at home who have contributed have actually ended up as authors on papers in peer review journals, which is fantastic.

 Chris -   So, they should too, because at the end of the day, they're doing the work.  But what about if they're young because some journals and I know of one scientist who refused to let his son, who actually made a seminal discovery that led to the piece of work, not being included on the publication because he was only 12 at that time?

 Dominic -   Well, there certainly have been school children I think have been involved in Galaxy Zoo, so that's very good to see.

 Chris -   Pretty good to apply to a university with a publication under your belt already in an academic journal.


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