Scientists at NASA are using Twitter to track and learn about the polar lights.
Aurora Australis. Image Credit: Keith Vanderlinde, National Science Foundation
In 2011, the sun emitted about a billion tons of hot, high energy particles called plasma that created a disturbance called a geomagnetic storm in the Earth’s magnetosphere. The result was a stunning display of northern lights that reached as far south as Alabama. Almost immediately, people pulled out their phones to tweet about the event. Dr. Elizabeth MacDonald, a research astrophysicist in the heliophysics department at NASA Goddard Space Flight Center, took notice of the thousands of aurora-related posts flooding Twitter. Inspired by this, MacDonald created Aurorasaurus, a website that uses public tweets to map where the aurora occur globally.
Aurora occur when the sun’s outer atmosphere, which extends far into space, interacts with Earth’s magnetosphere. Essentially, 1 million tons of plasma or solar wind leave the sun every second en route to Earth. The shape of Earth’s magnetosphere (the region around Earth that is controlled by its magnetic field) protects the Earth from the solar wind by forcing those particles to flow along the field lines to either the north or south pole. This means that the aurora is always occurring in that region. On top of that, sometimes there are coronal mass ejections, or what MacDonald calls a “glitter bomb,” from the sun.
Animation of solar wind hitting Earth’s magnetosphere. Image Credit: NASA
A coronal mass ejection is a massive cloud of solar plasma that allows for some of the charged particles to enter Earth’s magnetosphere. When those charged particles interact with the neutral particles, they become excited and emit photons, resulting in aurora borealis (northern lights) or aurora australis (southern lights). If the charged particles interact with oxygen, they produce a green or red light; if they interact with nitrogen, they produce violet or blue.
Auroral activity is typically predicted and measured using satellites. However, MacDonald says that using Twitter and other social media can help scientists track the aurora on a larger scale.
“Satellites are great, but they’re expensive, and they can’t be everywhere all the time,” MacDonald says.
People and Twitter, on the other hand, can be mostly there. When MacDonald and her team looked at the numbers, they found that an increase in tweets about aurora correlates with the presence of geomagnetic activity 91 percent of the time. MacDonald used this to her advantage by setting up the website to recognize any tweets that contained keywords relating to aurora. Volunteer website users would then verify that the person was referring to an actual aurora, as opposed to a city or the Disney princess. Once verified, the tweet would appear on an interactive map on the site, which also indicated the predicted visibility of the aurora in different areas. The website would then send registered users in the area a notice of the auroral activity, allowing them a chance to see the aurora and tweet about it as well, providing more information to MacDonald and her team about the aurora in real-time. For non-Twitter users, reporting to the website or through free apps is also an option.
MacDonald says the project has been successful in filling gaps in current knowledge about auroras. The project has helped scientists understand basic types of auroras better and has aided in understanding rarer types of aurora that occur at strange times or at lower altitudes. One of MacDonald’s favorite discoveries is “Steve.”
Initial image of “Steve.” Image Credit: Dave Markel Photography/ESA
“Steve” is a purple and green light display in the sky that was discovered in early 2016 by aurora enthusiasts in Alberta, Canada. They reported the phenomenon to Aurorasaurus, commenting on how it didn’t seem like a typical aurora. It was nicknamed “Steve,” referencing a scene in the children’s movie “Over the Hedge,” where the characters encounter a hedge and, not knowing what it is, playfully decide to call it Steve.
To MacDonald, “Steve” is just an example of how Twitter and social media in general is creating citizen scientists.
“This project has helped facilitate discussions between the enthusiasts and the scientists. We’ve learned to listen to each other and appreciate each other’s perspectives,” she said.
MacDonald and her team are now documenting their results about “Steve” for publication in a journal. In the future, other social media sites like Flickr and Instagram also can be used on their platform to continue tracking and learning about the aurora from citizen scientists.
Sanna Darwish is a student science writer at NASA Goddard Space Flight Center and a senior hearing and speech sciences major at the University of Maryland.