NASA spots unexpected X-shaped structures in Earth's upper atmosphere — and scientists are struggling to explain them Livescience.comAlphabet Soup: NASA's GOLD Finds Surprising C, X Shapes in Atmosphere Science@NASAStrange X and C shapes discovered in Earth's ionosphere indy100NASA Discovers Strange Spectral Formations High Over the Earth FuturismStrange Letter-Shaped Structures Found In The Electrified Layers Of Earth's Atmosphere IFLScience