Hanny Van Arkel is a 25-year-old school teacher who lives in Holland with her German Shepherd, Janey. She enjoys playing the guitar and loves Brian May. She also found the first-ever voorwerp. Hanny is a citizen scientist.

Hanny’s voorwerp (meaning object in Dutch), is a weird green blob spotted by Hanny in 2008. It is a giant glowing cloud of hydrogen illuminated by light emitted up to 70,000 years ago by a quasar (an extremely energetic galaxy with a supermassive black hole at its center). What is more, a study published online last week in the Astrophysical Journal Letters reveals that the quasar lighting up the gas has since burned out, making the voorwerp a kind of a light echo of a dead quasar. Yale astronomer Kevin Schawinski said this newly discovered system was "like the Rosetta Stone of quasars," and explained that if it hadn’t been for the discovery of the voorwerp, they never would have known.

As it happens, Kevin was the co-founder of Zooniverse, the citizen science organisation through which Hanny made her discovery. Zooniverse’s first project ‘Galaxy Zoo’ was born out of Kevin’s PhD which required the classification of 900,000 galaxies, a task which computer systems are notoriously bad at. Kevin began to flag around 50,000 galaxies and turned to the public for help. To date, more than a quarter of a million people have made more than 150 million galaxy classifications.

The team behind Zooniverse were by no means the first to harness the powers of the ‘citizen scientist’. Almost a decade earlier, the Search for Extraterrestrial Intelligence or ‘SETI’, had launched SETI@home, which still runs today. The project requires volunteers to install a software programme on their computer that automatically searches radio wave data for extra-terrestrial activity. Once they’ve wandered off to make the tea or feed the cat, the computer goes into hibernation, the programme kicks in and the volunteers find themselves quite effortlessly participating in the biggest alien hunt known to man.

But citizen science actually has its roots much further back in time. Rewind to 1900 for example, when the first conservationists were just starting to emerge. Uneasy with the Christmas tradition of going out on a hunt, they initiated the Christmas Bird Census which encouraged volunteers to go out and count birds during the holidays, rather than shooting them. Since then scientists have come to rely on citizens to help them with their handiwork in all kinds of diverse research areas. My personal favourites include Nasa’s Stardust@Home (searching for interstellar dust particles), foldit (working out how proteins fold) and The Open Dinosaur Project (where anyone can help in building a comprehensive database of dinosaur limb bone measurements).

While citizen science is clearly not a new phenomenon it has certainly expanded rapidly and diversified in recent years, helped along greatly by advances in technology. Whereas in the past volunteers have been used for data collection, they now both analyse the data (as with Kevin’s galaxy classification) and sometimes even form the data set themselves.

The BBC’s 'LabUK’ is one example of the latter. They completed their first experiment in spring this year. ‘Can you train your brain?’ was a study designed to test whether there was any truth in claims that computer brain training games could make your brain younger, better, faster or even bigger. Six months after launching, 13,000 people had taken part in the study and the results (showing absolutely no difference between those who brain trained and those who just used the internet for six weeks), were printed in the journal Nature.

With no curb in the popularity of such projects, the future looks bright for citizen science with many exciting projects on the horizon. Zooniverse have just launched ‘Old Weather’ which asks the public to help transcribe the log books of sailors. Seamen had to note down the conditions every 4 hours whilst at sea, leaving us with a precious picture of the planet’s weather for several centuries. The problem is, there are around 250,000 log books in the UK alone, not to mention in other parts of the world, and computers cannot read them. Once again, citizen science comes to the rescue. Climate scientists are excited for obvious reasons.

Lab UK’s next project, launching early next year, is set to be one of the biggest social studies of the British population ever conducted. Last month, the BBC LabUK team were also awarded the Prix Europa Emerging Media award and editor Richard Cable said several other European broadcasters had expressed an interest in launching similar projects.

In fact, there are now so many citizen science projects, that a match-making site has emerged. Scienceforcitizens.net aims to bring together millions of citizen scientists and match them with the thousands of potential projects offered by researchers in accordance with their interests.

Why do so many people want to give up their time to take part in these projects? There are often additional (modest) motives involved. For example, Zooniverse tend to introduce an element of competition into their projects. They’ll pitch cities up against each other to see whether Birmingham or Brighton have classified the most galaxies, and in their new project ‘Old Weather’ volunteers who transcribe a certain number of logbooks are named as the ships' captains. A pre-requisite of BBC LabUK’s projects is that participants get to find out something new about themselves. And of course if you’re analysing interstellar dust or scanning outerspace there’s always the chance you might spot a ‘thing’ that you could call your own.

But in a recent survey conducted by Zooniverse to investigate the motivations of their volunteers, the resounding sentiment was quite simply: ‘we want to contribute to science’.

Thus from alien searching to logging the limb bones of dinosaurs, counting sparrows, mapping the universe or training your brain, the curiosity of literally millions of lay scientists has contributed to some fundamental pieces of research, and for that, scientists will be forever grateful.

About the Author: Hannah (or Nan as she’s usually known) grew up on a farm in Yorkshire, England. After spending time living in Africa, Japan and New Zealand, she read Human Sciences at Oxford and later went on to train as a science journalist at City University, London.  Earlier this year she was selected for the European Union science project RELATE and travelled to Brussels to report on new research.  She now works at the BBC on their national science participation project: BBC LabUK. She likes cake. A lot. You can follow Nan's tweets at @BabbleNan

The views expressed are those of the author and are not necessarily those of Scientific American.