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Ultrahigh-energy cosmic rays twist and turn on their way to Earth, which has made it nearly impossible to identify the colossal monsters that create them.
For decades, astronomers debated whether a particular smudge was close-by and small, or distant and huge. A new X-ray map supports the massive option.
Hot spots have been discovered orbiting just outside the supermassive black hole at the galaxy’s center. Their motions have given us the closest look at that violent environment.
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