If you’ve looked at social media feeds in the past week, they’ve likely been jammed with bedazzling photos of the aurora borealis – the northern lights – in a spectrum of colors that go beyond the usual green lights commonly associated with the phenomenon.
The auroras occur when the Earth’s magnetic field becomes disrupted by intense solar winds traveling at 3 million mph that carry plasma particles that interact with gases – namely oxygen and nitrogen – in the planet’s atmosphere.
But what provides the magic of these lights is happening at the molecular level in these gases.
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Why are there different colors of Northern Lights?
The colors we see emanating from the aurorae are a direct result of activity happening at the atomic level in air molecules. When plasma particles from solar flares collide with molecules in the atmosphere, the electrons jump due to their excited energy level. As the electrons return to their normal state, the excess energy is released from the atom as a photon of light. Oxygen atoms emit a ghostly green color, the most common type of Northern Lights.
Recent displays witnessed as far south as Florida and Texas, however, appeared in reds, blues and purples. These colors are caused by a combination of nitrogen, hydrogen and helium present at different levels in the atmosphere where oxygen is thinner.
Will we see the Northern Lights again?
Yes. According to predictions by NASA scientists, the next peak in the kind of solar activity that spews large eruptions in energy and material – called a solar maximum – will occur in July 2025. The northern lights are expected to get stronger and more frequent as the solar maximum approaches.
For now, NASA scientists have more data to work with to study the impact solar flares have on Earth’s upper atmosphere, satellites and infrastructure in space.
CONTRIBUTING Doyle Rice and George Petras, USA TODAY
SOURCES: NASA, AuroraWatch UK / Lancaster University, Reuters
Dr. Thomas Hughes is a UK-based scientist and science communicator who makes complex topics accessible to readers. His articles explore breakthroughs in various scientific disciplines, from space exploration to cutting-edge research.
