Why is earth at risk even when asteroids are traveling millions of miles away?

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NASA, the United States space agency is now busy developing a planetary defence weapon to protect the earth from dreaded events like asteroid hits. However, what makes this weapon necessary? Is earth going to face an imminent doomsday scenario? Let us check it out.

The universe in which we live is so huge and gigantic, and just within our solar system, there are hundreds of thousands of asteroids and meteorites wandering across space. Sometimes, these rogue space bodies come very close to the earth and in the worst cases, they will plummet to the earth's atmosphere.

If the rogue body approaching the earth is small, it will burn up as they enter the planet's atmosphere. But giant space bodies will overcome this burning process and will hit the earth's surface in a force that might be equivalent to the blast of a thousand nuclear bombs.

NASA's asteroid tracking system has already detected hundreds of rogue asteroids that can be classified as near-earth objects. Even though during its close fly, these asteroids will be thousands of miles away from us and the chances of a possible impact are pretty low, at least in the near future. However, experts believe that there are several factors that could increase the chances of the earth being hit by rogue space bodies from deep space.

One such factor is gravitational keyhole. According to experts, the gravitational keyhole is an area in space where rogue bodies like asteroids get affected by the gravitational pull of nearby planets. Making things clear, if an asteroid enters the gravitational keyhole of the earth, it will be drawn to the planet's surface, and the possibilities of an impact become very high.

The Yarkovsky effect is another crucial factor which may make an asteroid vulnerable for a collision with the earth. As per space experts, the Yarkovsky effect can be defined as the heat exerted from an internal object like a star which is capable of modifying the spin of an asteroid. If it happens, the original trajectory of the space body may change, and it will begin a deadly collision course.

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