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STEVE (short for "strong thermal velocity enhancement") is a long, thin line of hot gas that slices through the sky for hundreds of miles. The hot air inside STEVE can blaze at more than 5,500 degrees Fahrenheit (3,000 degrees Celsius) and move roughly 500 times faster than the air on each side of it, satellite observations have shown. Whereas the northern lights occur when charged solar particles bash into molecules in Earth's upper atmosphere, STEVE appears much lower in the sky, in a region called the subauroral zone. That likely means solar particles aren't directly responsible for STEVE, Live Science...

Today it's a desert. Two hundred thousand years ago, perhaps it was home. The San people of southern Africa carry one of the oldest maternal DNA lineages on Earth. Now, researchers think they know the precise place our earliest maternal ancestor called home. (Image credit: Shutterstock) Two hundred thousand years ago, the earliest shared ancestors of every living human on Earth rested their feet at a verdant oasis in the middle of Africa's Kalahari Desert. Here, in a patchwork of now-extinct lakes, forests and grasslands known as the Makgadikgadi paleowetland, our greatest grandmothers and -grandfathers hunted, gathered and raised families...