This is the type of event that we don't often get to tell you about, and that is a source of both awe and concern. Dating back to the origins of the Universe, asteroids have been wandering through the sidereal forever, silently traveling an infinite number of kilometers and punctuating, or even ending, their course by coming in contact with a more or less massive obstacle.
Fortunately, although we are sometimes "in the way", our beautiful blue planet protects us from many of these objects thanks to its thick atmosphere, which reduces most of the meteors and other space projectiles to dust.
But sometimes, they're bigger and manage to cross this barrier. Thus, in its history, the Earth has experienced more or less powerful asteroid impact events, the results of which have ranged from craters that were several kilometers wide to a serious climate upheaval that decimated millions of living beings. Today, we're able to see these asteroids flying at a distance, and sometimes getting very close to us, as was the case in recent days.
More fear than harm
Although the event of Wednesday, July 24 may have been concerning, NASA was quick to reassure us by saying that none of the three asteroids would have been large enough to pose a threat to the Earth. In truth, the numbers are the most impressive part of this event: take one of them, which was named "2019 OD". It was 357,538 kilometres away from the Earth's surface, which sounds far, but isn't that far, considering that the Moon is 384,472 kilometers away from us.
In terms of speed, the asteroid, which has a diameter of a hundred metres, grazed our home at a speed of 69.082 km/h. Lagging behind it, the two other asteroids named "2015 HM10" and "2019 OE" cruised by at a speed of about 32,000 to 35,000 km/h. That's the equivalent of doing two round trips between London and Sydney in less than an hour... The Concorde can't compete!
Humanity is preparing its space defenses
Just like a child getting hit in the face by a soccer ball at the playground, we aren't immune to being hit by a massive asteroid someday. Fortunately, researchers are working hard and there are currently many projects underway to avoid a disaster. We could, for example, mention NASA's Double Asteroid Redirection Test (DART) project, the aim of which is to divert the moon from an asteroid using a probe in 2022.
An ambitious project that could, on a larger scale, allow for the creation of devices that deflect asteroids away from Earth. More generally, we can also thank recent technological advances in the field of sky observation, which make it possible to detect asteroids better and better, so that, in the event of an emergency, populations located on future crash zones can be alerted and evacuated.
The teams' progress also allows us to detect small objects, like asteroid "2019 MO", a 4-metre asteroid detected by the University of Hawaii a few hours before it was dissolved in our atmosphere.
Take a look at the video above for more on the three asteroids that just came very close to hitting the Earth...