What would happen if a comet hit Earth in six months?

  • 23

This article is published in partnership with Quora, a platform on which Internet users can ask questions and where others, specialists in the subject, answer them.

The question of the day: “If a comet were about to hit Earth in just over six months (as in Armageddon), how prepared are we really to hijack/destroy it? Is there a ship ready to save a few hundred of us?”

The answer of Jean-Pierre Deslandes:

Let’s admit: in six months, a comet or a large asteroid will hit the Earth if nothing is done, as in Armageddon. What do we do?

For starters, no, this film directed by Michael Bay is NOT a documentary. There is a game NASA that we pass on to aspiring astronauts, which consists in counting the errors of the film. The record is 168. Moreover, given the size of the object, a simple nuclear bomb (even 100 megatons) would do almost no damage. Now that that’s said…

Already, it would be surprising if we discovered such an object only six months before it hit us. The comets, we see them coming from afar. From far away. Asteroids, a little less. But most of the large asteroids are known and none so far have really threatened the planet. On the Torino scale, which goes up to 10, the most dangerous has arrived at level 1, called “normal”, which means: the risks of collision are extremely unlikely in the decades to come.

However, let’s look at two scenarios.

Scenario 1: the object is seen years before the collision (the longer the better)

There, we are spoiled for choice. We can deflect it with a small impactor. This is what NASA will test on la mission DART: a flick which, from a few millimeters to billions of kilometers, can deflect theasteroid or the comet thousands of kilometers away, which is enough to avoid collision with Earth.

We can also put a probe in an orbit such that its mass would be enough to deflect the asteroid. Or paint one side white and let the sun’s rays push the object.

Otherwise, a nuclear explosion next to the asteroid: why not, but a lot depends on its internal structure. If the asteroid is porous, it will absorb the shock wave without flinching.

Scenario 2: the object is spotted only six months before impact

There, one cannot envisage deflecting the object. That’s why you had to take inventory of the objects before… Well, it stinks a bit.

But it all depends on the size of the object and its speed. For fun, you can do simulations on the city of your choice with Asteroid Damage Visualization Map. Basically, up to 1 kilometer, it can do significant damage on the scale of a country like France, but not enough to destroy humanity. At worst, we will try to evacuate the front impact zone.

Let’s now assume the worst case: an object that can wipe out all life on Earth, a 20 kilometer object, for example – note all the same that this very big thing has no chance of arriving without being seen for decades , even centuries in advance.

We don’t have the technology to send people elsewhere in the long term. We are already struggling to send a few people to the Moon, let’s not even talk about Mars. Moreover, survival on planets other than Earth would be much harder than the worst situation on Earth. As for an exoplanet as a potential plan B, we are not about to consider it for a few millennia.

So there we are all dead. At best, the astronauts of the ISS will survive a few months longer than us, before dying of starvation or asphyxiation.

Conclusion

Unless our astronomers suddenly become miros, there’s no way an asteroid threatening humanity within six months hasn’t been sighted. In 2017, astronomers estimated that they knew 96% of near-Earth objects, and NASA considers the probability of an object over 50 meters to hit us to be nil.

Sign up for the Slate newsletterSign up for the Slate newsletter

Sleep peacefully. A bus is much more likely to kill you than an asteroid.

Reading time: 3 mins This article is published in partnership with Quora, a platform on which Internet users can ask questions and where others, specialists in the subject, answer them. The question of the day: “If a comet were about to hit Earth in just over six months (as in…

Reading time: 3 mins This article is published in partnership with Quora, a platform on which Internet users can ask questions and where others, specialists in the subject, answer them. The question of the day: “If a comet were about to hit Earth in just over six months (as in…

Leave a Reply

Your email address will not be published.