Cosmic shields: how atmosphere and gravity protect Earth from asteroids

In Douglas Adams’ famous five-book trilogy The Hitchhiker’s Guide to the Galaxy, the substance that describes Earth is this: almost harmless. This forces us to think about the impact we can actually have on our planet’s cosmic environment..

Just like in the book, our planet is routinely in danger of destruction, whether from the construction of new space routes or from orbiting asteroids colliding with our little blue world.

In fact, in the non-fiction world, there are several asteroids that are under constant surveillance and have a “potential” risk of impact. There are even projects being developed to reduce the already low probability of a new wave of mass destruction.

But while we may be practically harmless, we are certainly not defenseless. The Earth naturally has a defensive shield against threats from spaceBelieve it or not, we are bombarded every day. But we survive in good health. Learn more about asteroids, shooting stars, and Earth’s protective shield.

An asteroid, meteor, shooting star or meteorite?

Before we explain how we defend ourselves, let’s explore why we need to defend ourselves. Our planet is located in the Asteroid Belt, which is located between the orbits of Mars and Jupiter.

The celestial bodies in these regions also revolve around the Sun. and can sometimes intersect the orbits of other asteroids and even planets.Asteroids are generally large celestial bodies that vary greatly in size, have irregular shapes, and may be composed of rocks, minerals, and metals.

When two asteroids collide, they can break apart and form meteoroids, which are nothing more than fragments of smaller asteroids that continue on their orbits.

But the gravitational pull from nearby planets can more easily pull these smaller pieces away from their orbits, and when they are on a collision course with planets and moons, they are called meteors.

And if the meteor is large and durable enough to survive the fall, it eventually becomes known as a meteorite. Famous among dreamers and sky watchers are shooting stars, It is nothing more than a white-hot rock piercing the shield of the world..

All The Earth is bombarded by at least 17 thousand meteors every dayBut only a small percentage, between 5% and 10%, manage to pass through the world’s shield unharmed.

You will understand better, even if all these rocks fall from space, the earth’s shield is so effective that the probability of being hit by a meteor is lower than the probability of being struck by lightning. You are safe.

So what is this shield?

Look up and you will see it. Okay, they are not visible, but they are there. The Earth’s shield consists of all the layers of the atmosphere, which are mainly formed by the movement of our planet’s core, with an added electromagnetic field.

While the electromagnetic field helps protect our planet from solar flares and other types of radiation that are harmful to our survival, The atmosphere helps destroy anything that tries to enter our skies uninvited..

When celestial bodies, whether meteors, dust, or even space debris produced by human missions, enter the atmosphere, the speed of descent is so rapid that the friction between the air, now rich in oxygen and other atmospheric gases, and the surface of the object will cause it to burn. If the object is small, it will burn to pieces, but if it is large and durable, it can become a meteorite.

But some researchers think that, in addition to the atmosphere and electromagnetic fields, the gravitational field could also contribute to our safety by modulating the forces that would destroy objects with a potential risk of collision. Gravity will play a dual role, attracting the problem and then modulating itself to destroy it..

What about dinosaurs?

Okay, you caught me. There have indeed been some reports of catastrophic celestial bombardments on our planet. see the mass extinction of dinosaurs. Our shield is not infallible, there are limits to what it can burn to dustHowever, to be able to predict new collisions, astronomers are constantly monitoring celestial bodies that pose a potential risk.

By knowing what they are, what they look like, and where they come from, space agencies can plan for a less catastrophic future. For example, experimentally, the DART mission in 2022 was the pioneer in trying to deorbit a celestial body and succeeded in reaching the asteroid Dimorphos.

But as far as we know, our blue home will be safe for decades to come, protected only by Earth’s natural shield, which is bravely doing its part, while we investigate possible solutions against new apocalyptic asteroids.

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