Towards a galaxy of citizen researchers

Astronomers, trying to classify galaxies through their shapes, realised that they could not leave everything to computers. Machines are not good at pattern recognition, but humans are. The problem: there are billions of galaxies, and people get bored more quickly than computers.

The solution was ‘citizen science’. The astronomers set up a website called Galaxy Zoo and appealed worldwide for help to classify the galaxies according to shape. Immediately they received such a response that within a couple of days they were doing 70 000 galaxy classifications an hour.

‘Taken together those classifications are more accurate than those supplied by professional astronomers,’ said Chris Lintott, a professor of astronomy at the University of Oxford and one of the founders of Galaxy Zoo. ‘The crowd does not make mistakes, and it has endless enthusiasm for this task of sorting through pictures of the Universe.’

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‘The crowd does not make mistakes, and it has endless enthusiasm for this task of sorting through pictures of the Universe.’

Involving the crowd adds a new option for carrying out scientific research. Before the 20^th century, science was largely a field for enthusiastic individuals – ‘gentleman scientists’ with their own funds and plenty of free time, or scientifically minded industrialists. In the past half century, science has been professionalised, and is largely pursued by specialists in universities or research centres. Citizen science followed in the 1990s, as the internet allowed people in different locations to be guided and to contribute.

Citizens help analyse data

In some cases, the citizen scientists gather data that will be analysed by professional researchers. The EU launched its Citclops project in 2012 (Citizens’ Observatory for Coast and Ocean Optical Monitoring), aiming to get people to collect sea water samples for analysis for sewage and sediment content. By mobilising tourists and locals in northern Spain, the project is aiming to collect 16 000 inputs a day, compared with 130 when the work is left to inspectors.

From whale song to ancient climate records, Chris Lintott, a professor of astronomy at the University of Oxford, UK, believes in citizen science to digest huge amounts of the data scientists have to cope with. © CERN Galaxy Zoo works the other way round. Professional scientists gather the data through powerful telescopes that can register billions of galaxies. The shapes of galaxies indicate their histories, so collectively they tell the story of the Universe – but there aren’t enough specialists to classify them. Since it was set up in 2007, hundreds of thousands of people have helped carry out classifications.

The crowd sometimes also comes up with more than it is asked to. One volunteer spotted a strange blob underneath the galaxy she was classifying. It turned out to be a galaxy-sized gas cloud driven by a special type of black hole – something that astronomers were sure existed but had never observed.

Beyond astronomy

Researchers in other disciplines face the same ‘data flood’ that overwhelms astronomers. So the idea has been expanded under Zooniverse, a collection of citizen science projects.

In ‘Old Weather’, volunteers digitally transcribe weather and sea ice data from the log books of United States Arctic exploration and research ships that were at sea between 1850 and 1950. They have transcribed more than a million pages of naval log books and recorded more than a million weather observations.

‘Whale FM’ is categorising the sounds made by killer whales and follows the travels of individual animals around the oceans: volunteers listen to an audio clip of whale sounds and view them in data form.

‘The solution is to invite millions of people to come along and join us in our scientific adventures,’ said Lintott. ‘This is science education, but it's also the cutting edge. People actually get to help us. We are not only educating these volunteers, but we can change their lives and we can change their attitudes to science as well.’