Over 40,000 asteroids close to Earth discovered: the new challenge for planetary defence
The number of asteroids close to Earth has exceeded 40,000: a milestone that shows how much our ability to scan the sky has grown in recent decades. These objects, known as Near-Earth Objects (NEOs), can come as close as 45 million kilometres to Earth's orbit, but only a small proportion of them pose a real risk. According to the latest data [...]
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