That's because what humans perceive as the North Star changed over time. Ancient Egyptian astronomers in the Old Kingdom, between 4,700 and 4,100 years ago, had a North Star, which they symbolically represented with a female hippopotamus, according to Giulio Magli's book " Architecture, Astronomy and Sacred Landscape in Ancient Egypt." But it wasn't Polaris. Who discovered the North Star? That's a complicated question. But Polaris also happens to be far away for a star that's visible with the naked eye, which reduces its brightness. Even so, it's about 2,500 times as luminous as our sun, because it's a massive supergiant with a diameter nearly 40 times larger than the sun and five times the mass. Its looming presence leads some people to think of it, mistakenly, as the brightest star in the sky (it's actually the 48th brightest). Polaris is attention-getting, because unlike all the other stars in the sky, Polaris is in the same location every night from dusk to dawn, neither rising nor setting, according to Fienberg. "From other latitudes in the Northern Hemisphere, if you face due north at night and look the same angle above the horizon as your latitude (for example, look about halfway up – 45 degrees – if you live in Portland, Oregon, at latitude 45 degrees north), you'll see Polaris shining there." "So, if you were to stand at the North Pole - latitude 90 degrees north - at night and look straight up, you'd see Polaris directly overhead," Fienberg says via email.
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