Earth is surrounded by some celestial neighbours in the soar system and then there are the nasty ones that come calling, threatening to destroy everything in their paths! These are known as Near-Earth Objects (NEOs), including comets and asteroids that travel close to the Earth. Any asteroid or comet that approaches our planet less than 1.3 times the distance from Earth to the Sun can be considered a NEO. However, the relieving fact is that most NEOs pose no peril at all. It is just a small percentage of Potentially Hazardous Asteroids which can put all life on Earth at risk.
But which are these nasty asteroids that hurtle towards the Earth with the potential of causing a global Armageddon? NASA defined these asteroids as the rocky fragments left over from the formation of the solar system about 4.6 billion years ago. Occasionally, the orbital paths of asteroids are influenced by the gravitational pull of planets, which can alter their paths. Remember that asteroid which struck straight the Earth and ended the age of dinosaurs? This was one of the examples in history.
However, NASA's Center for Near-Earth Object Studies keeps an eye on all the near-Earth objects in space to detect any potential harm from these celestial bodies in advance. The space agency defines a potentially hazardous asteroid based on some parameters to know the threat of asteroids making close approaches to the Earth. There are still a few categories of asteroids which pose a threat to Earth and humankind. Based on perihelion distance (q), aphelion distance (Q) and their semi-major axes (a), NASA divided near-Earth asteroids into several groups. Here is what NASA shared.
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