Mapping the Moon — and more
What: CosmoQuest, a citizen science web project that contributes real science to NASA space missions through the use of volunteers.
More info: cosmoquest.org
Regular folks, given the right tools, can count craters on the moon as accurately as trained professionals, according to a new study led by a researcher at the University of Colorado.
A paper published earlier this month in the online journal Icarus reported that, as a group, volunteer counters who examined NASA high-resolution images of the lunar surface in the area of the Apollo 15 landing performed just as well in identifying individual craters as professionals with five to 50 years of experience.
The crater-counting was accomplished through CosmoQuest, a citizen science web project that contributes real science to NASA space missions through the use of volunteers.
Volunteers participating in the CosmoQuest work also are helping planetary scientists count craters on Mercury and the asteroid 4-Vesta, the brightest and second-largest in the asteroid belt.
"This has not really been studied before," said Stuart Robbins, a research scientist at CU's Laboratory for Atmospheric and Space Physics, who led the study.
"The professionals have a natural variation in how they ID craters. From this work, we see that the untrained volunteers as a group are within the overall range of the experts. It's not that they match all of the experts exactly, but they fall well within the experts' range of results."
The fact that volunteers, rewarded with nothing more than the simple thrill of participating in planetary science, can help astronomers with some of their leg work — in a time of shrinking grant money and limited research budgets — is significant, Robbins said.
"This means we can actually use the crater data that the volunteers gather," said Robbins, who is also affiliated with the Southwest Research Institute in Boulder. "We can actually get volunteers who are freely using their time to gather the data for us, so that we can focus on doing science."
Results for citizens and scientists statistically similar
The images being studied by experts and the volunteer crater counters were recorded by NASA's Lunar Reconnaissance Orbiter, launched in 2009.
Several images of small sections of the lunar surface were put online, and the planetary science professionals and the citizen scientists were asked by CosmoQuest to identify craters in images that were at least 18 or more pixels, Robbins said. The area of the images being studied for the project was about 1.4 square miles, or roughly the area of 1,000 football fields.
Eighteen pixels in the images are equal to a crater about 35 feet wide, Robbins said.
The variation in results for those counting craters can be significant for experts and volunteers alike. Even the total craters counted by experts in a single image varied by as much as 100 percent. But when averaged by group, the population of craters found by the experts and citizen scientists were statistically similar.
Robbins has calculated that there are roughly 500 million craters on the moon larger than about 35 feet across created by impacting objects.
"The key point here is the difference between two professionals is significant," said Pamela Gay, principal investigator at CosmoQuest, and an assistant research professor in the STEM center at Southern Illinois University — Edwardsville. "But the difference between the group results of all of the professionals and the group results of all of the amateurs is insignificant.
"While there is a great variation between individuals, if you take the group response of the professionals, and the group response of the amateurs, you get, for all intents and purposes, the same result. The group mind is better than the individual."
Mercury is also a project target
Gay, who developed CosmoQuest and is a co-author on the moon mapping study, said the site provides much more than a handy crowdsourcing tool for astronomers.
"There are lots of sites that ask people, 'Do this, do that, click here, mark that,'" she said. "With CosmoQuest, we want people to come to our website to do science, and learn the importance of what they're doing. We want them to be treated the same way we treat our students, our colleagues."
Through features such as blogs, forums, online hangouts and galleries, Gay said, "We're trying to create a community of people learning and doing science, just like you would see if you were at SwRI or the University of Colorado. The difference is, our community members have day jobs. When I'm meeting (online) with a volunteer, I'm meeting with them after they get home and put their kids to bed."
Gay said the mapping of craters on Mercury is well underway.
"The thing about Mercury is, it has been hit by some very large asteroids in the past," Gay said. "These collisions threw up bedrock, boulders and chunks of rock that have created secondary craters.
"We're trying to decouple what are primary craters and secondary craters. It is important to understanding the history of Mercury, and that is one of the things we're going to be looking at."
Robbins, the co-science lead for the moon mapping project and the science lead for the Mercury project, believes there could be many other assignments appropriate for citizen scientists to help the professionals.
"Anything where we need a lot of simple features recognized or classified, as long as we keep it simple," he said. "These are volunteers. Identifying a circle on a surface isn't incredibly difficult.
"It doesn't take a lot of specialized knowledge."