NASA recreates Earth’s northern lights
Scientists have harnessed the tools needed to stage Earth’s most colorful light show, and they have brought the Aurora Borealis into a lab at NASA’s Langley Research Center in Hampton, Va.
Their simulation, generated by a device called Planeterrella, combines all of the necessary ingredients – a magnetic field, charged particles, and a sphere, to display a colorful reenactment of Earth’s Northern Lights.
“It recreates the atmosphere of the Earth at 80 km in altitude when an aurora is occurring. The aurora is created when particles, originally from the sun, precipitate into the atmosphere,” explained Guillaume Gronoff, a research scientist at NASA Langley who lead the creation of Planeterrella.
According to Gronoff, the Planeterrella machine is a spinoff of an experiment from the 19th century called the Terrella, which first demonstrated the glowing result of electrically charged particles mixing with a magnetic field. Gronoff and his team upgraded the old experiment by adding several spheres, which allows them to recreate the auroral ovals that occur on Earth and several other planets.
“For example, we can show the reaction when Io, the satellite of Jupiter, sends particles to Jupiter. We can also simulate the aurora at Neptune and Uranus, when their magnetic fields are directly pointing towards the sun,” said Gronoff.
There are approximately 10 other Planeterrella machines in Europe, and the first was created by Gronoff’s PhD advisor, Dr. Jean Lilensten, from the Centre national de la recherche scientifique (CNRS) and the Institut de Planetologie et d'Astrophysique de Grenoble (IPAG) in France.
The Planeterrella at Langley is among the first in the U.S., and its creation was made possible by a cooperation between the Virginia Air and Space Center (VASC), NASA Langley’s Science Directorate and the Research Opportunities in Space and Earth Sciences (ROSES) program.
Studying auroras and the relationship between the sun and the Earth is a key focus area of NASA’s Science Mission Directorate, but the Planeterrella machine is primarily used for demonstrating to others how each variable interacts to create an aurora.
“The Planeterrella allows us to create analogies with existing processes, like the aurora at Mars, which do not have a global magnetic field, but several localized magnetic fields, or Uranus and Neptune, when the magnetic fields of those planets point towards the Sun,” explained Gronoff.
Gronoff cautions that this experiment is only an illustration; more complex phenomena are occurring in the magnetospheres of planets. For example, there are various gases on each planet that can create different color effects within auroras. Gronoff is planning on incorporating this variable using a few extra magnets and some carbon dioxide to simulate the aurora at Mars.
The Planeterrella and its vibrant demonstration will be displayed at the VASC museum in a few months. A second machine will also be created to transport to local classrooms.
“The Planeterrella can help teach students about solar wind, how electrically charged particles follow the magnetic field and the exciting space missions NASA is launching to space to study these processes,” said Gronoff.