Since the “space-age” has started in the early 1960s, astronauts have taken more than 1.8 million photographs of the Earth from orbit, and about one-third of them (approximately 600,000) have been taken at night. But they don’t always know what they are looking at. You can help, announced NASA – the space agency needs your help to identify cities at night from space images.

cities at night: Japan cities
Night Image, Japan from space.

The photo above (id: ISS040-E-98889) captured on August 16, 2014, as the International Space Station was passing over the western Pacific Ocean, by the Expedition 40 crew. Bruce Boucek was the first to identify the cities in this puzzler image. James Titmas, Yumiko Stettler, and Jyo Sano also correctly identified the Nagoya area.

Cities at Night project

Cities at night, the European project STARS4ALL initiative, is creating a “Google maps” nocturnal version using pictures taken from space.

The Complutense University of Madrid (UCM) is leading Cities at Night, a citizen-science project to catalog such nighttime images. So far, hundreds of volunteers have classified nearly 20,000 images for the three-part project.

You can help to identify “cities in the night” images by visiting the “Lost at Night” website.

  • More than 17000 volunteers have classified, located and georeferenced night pictures taken by astronauts onboard the International Space Station to create the first high-resolution night color map.
  • The citizen science project, initially designed on three apps to be used by anyone who wants to contribute to the investigation, now aims to achieve its objective in developing small online games.

Astronauts take photos of our planet from the International Space Station every day. Some of them have already been published in different media, but almost half a million images remain unseen, stored in a huge database hold by NASA.

The project “Cities at night” aims at using all these images to create the first high-resolution night map of the world. The resolution of the map emerging from the project will be 10 times better than the one currently available, where cities look blurred when expanded. In addition to this overall enhancement, the new map will also include a brand new feature, which will enable users to detect the color of the light that our cities emit at night.

The minds behind the project are physicists and astrophysicists from the Universidad Complutense de Madrid. “These images cannot be cataloged automatically, that’s why we need citizen collaboration”, says Alejandro Sánchez, responsible for the project together with Lucía García. “When we started in 2014, we used three different applications through which more than 17,000 volunteers have helped us classify, locate and georeference these images. Now, we are working to transform these applications into games, so collaborating will not only be useful for science but also fun.”

“The result of this effort will not only be a beautiful map,” García says, “since this map will display data about sources of artificial light at night that scientists have been unable to study up until now.” The first results of ‘Cities at night’ are already supporting further research on light pollution, like the one performed by Dr. Ariadna García-Saenz (ISGLOBAL) evaluating the association between artificial light at night exposure and breast and prostate cancer risk.

Cities at Night belongs to the European project STARS4ALL, coordinated by Universidad Politécnica de Madrid, raises awareness about additional effects, going several steps beyond the well-known inability to see the stars. Artificial light at night alters our biological clock, which has negative effects on human health and it’s also dangerous for plants and animals, threatening the general equilibrium of ecosystems.

The new map that these scientists will create represent very important data for researchers that will be able to evaluate these effects better and help us find ways of improving our energy efficiency and reduce the resources we waste on excessive street lighting and this is the reason the researchers have the commitment of donating 12 calibrated images to 12 different research projects studying light pollution and its effects from all kind of different fields.

However, the topic still generates controversy when it comes to safety. “It is not about switching all the lights off, but using them only when appropriate, directing them to the ground and keeping adequate intensity levels,” says García. “A heavily illuminated road with high contrast between some areas and others is actually less safe than another with uniform dimmed light.”

In the images of this new map, researchers will even be able to identify the lighting technology that is being used in each part of the city. This is especially important since the migration to LED technology usually involves a change of color and cold lights are installed instead of warm and what affects us negatively, since this kind of light is more energetic.


M. Özgür Nevres

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