Following its orbit around the Sun, the Earth is subject to impacts from comets and asteroids that can come very close to it. These bodies are named NEOs, Near Earth Objects, and may represent a significant hazard, witnessed by the many impact craters recognized around the world.
The annual probability of the Earth being struck by a large asteroid or comet (bigger than 1 Km in diameter) is extremely small, but the consequences of such a collision are catastrophic.
At the end of 2001, more than half of the larger and more dangerous Near Earth Asteroids had been discovered, and today, none of them represents a threat for humankind. But things may change, and for this reason, we should continue studying NEOs and the danger they may represent for Earth.
Read this introduction to answer to some basic questions about NEOs, asteroid, comets and impacts...
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What are asteroids and comets? |
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What happens when a NEO strikes Earth? |
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Have impacts already happened in the past? |
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How much of a hazard? |