In just one day the Earth experienced a missed collision with the asteroid 367943 Duende and the explosion of another asteroid in the atmosphere, injuring over 1000 people.
It was February 15th in 2013, was the day many realized that Earth is a vulnerable bubble.
Asteroids are a direct connection between our planet and interplanetary space. Craters like Barring in Arizona remind us of this: the dinosaurs became extinct due to the impact with an asteroid not far from there.
Yet somewhere in the universe asteroids can also carry life from one planet to another. The world awaits new landings on the moon and then on Mars, but I say: let's remember the asteroids, here are at least 4 good reasons to do so.
They can also kill us.
The Chelyabinsk accident was filmed by a camera car, before then no one had noticed the meteor. Fortunately, no direct victims of the explosion were reported. Next time we might not be so lucky. Ditto for the recent Puerto Rico accident, fortunately without consequences.
Sticking only to the asteroids already known, there is only a slim possibility that they could collide with the earth in the coming decades.
Among them, 6 are those with an "unpleasant" trajectory that can affect us in the next 150 years.
They can contain water
Astronomers debate the origins of water on Earth, how it may have arrived billions of years ago, brought by comets and asteroids.
NASA's Dawn space probe visited Ceres, the largest known asteroid, finding water on its surface. It is no coincidence that NASA itself classifies Ceres as an "ocean world".
They tell us how the solar system was formed
The surface of the asteroids is not affected by erosion like that of the Earth because the asteroids have no atmosphere.
This means that the craters on the asteroids are in a perfect state of conservation, presenting a perfect photograph of how much our solar system has gone through during the last 4 billion years.
In other words, asteroids function as real "time capsules" that tell us about the universe.
They tell us how the solar system will die
In 6 billion years ago, when the Sun has exploited all its hydrogen, it will begin to change becoming a white dwarf. It is a last stage for a star. During this transformation, the Sun enlarged until it swallowed up Mercury, Venus and perhaps us too.
At least 5 planets in the solar system, however, will survive this transformation. And with them several asteroids.
It is therefore clear that the analysis of asteroids coming from other points of the universe can tell us a lot about their interaction with other white dwarfs, and about the "shutdown" process that characterizes star systems. However, they will also be able to tell us a lot about the ideal places to host us when we start space colonization.
