the story behind pink  

18 Nov. 2009 | In short ‘Galaxy Zoo’ is an online astronomy project for everyone. Real astronomers ask the public – with or without a scientific background – to help them classify galaxies. Here’s a bit of a story behind, in case you want to know what I’m often talking about in my ‘blogs’.


Once upon a time there was an astronomer called Kevin Schawinski, who was investigating blue elliptical galaxies. Therefore he was dividing a lot of pictures into two categories: spirals and elipticals. He had done about 50,000 of them… in five days (!), when he figured it wouldn’t be healthy to go on like that. There are no computer programs which are accurate enough to do this, so one day he sat in an English pub with this other astronomer, Chris Lintott, and the idea of asking help was born.


Online help. From ‘the public’, all over the world. Kids, adults, professionals and people without any scientific background. They would explain to them in an online tutorial what shapes they could see in these beautiful pictures from our universe, taken by the Sloan Digital Sky Survey, and what buttons they would have to click. You could expect ellipticals, spirals (of which they also wanted to know in what direction they’re spinning), but also mergers – two or more galaxies which bumped into each other – and sometimes the odd star would be getting in the way.

With some support from universities in England and America and a few other scientists they set up this website in the summer of 2007, spread the word in the media and figured enough people would want to check it out so that they’d have the dataset of almost a million pictures (!) sorted in a few years or so. None of these pictures had been seen before, as they were taken automatically, but now every picture would have to be judged enough times, to be statistically certain. To their surprise, the project turned out to be such a success, that they couldn’t keep up with the tens of thousands of e-mails they were receiving and they even blew a circuit breaker in the computer room. After one year 160,000 volunteers together had made 60 million classifications, so every picture had been seen 60 times and the astronomers – nicknamed ‘Zookeepers’ – were working hard to write papers about what they had discovered through these results. 

To deal with all the questions people were asking, they set up a forum where knowledge could be shared between the ‘users’. They also kept everyone updated through their Galaxy Zoo blog and to show how much they value the help, they credited the volunteers by making an (online) poster with all of their names. Seeing that they wrote the science with them.


One of the papers they’re writing has ‘Hanny’s Voorwerp’ playing the lead part. Since nobody had seen these pictures before, there was a chance you’d find something on one of them, that would be a totally new discovery. Which Hanny’s Voorwerp turns out to be. They asked for time with other telescopes and got SARA, William Herschel, Isaac Newton and WIYN to look at it. Suzaku, XMM-Newton and the famous Hubble Space Telescope are on the agenda. All of this raised a lot of interest and got even more people to sign up and help along.

So now this original dataset had been looked at enough, but the Zookeepers still had this large group of enthusiastic people who basically asked for more. And even though they’re still busy working on the results of all of their clicks, they came up with ‘Galaxy Zoo 2’. The second part of the project asks more questions about every picture. For instance, not just: ‘is it a spiral?’ but: if so, ‘how many arms does it have?’ And who knows what we’ll discover with all of this?!


I can’t end this story with ‘the end’, as Galaxy Zoo is still very much ‘alive and kicking’. Volunteers learn a lot about astronomy themselves and communicate with others all over the world. They take the initiative to go out and spread the word as well, by giving lectures about it. It became more interactive with the professionals asking those volunteers to think along with them and to tell them their suggestions about improving the site. Teachers are using Galaxy Zoo in their classes and so this whole idea that started in that pub two years ago, spreads out over the world like an oil spill of knowledge and fun.