Par Martin Leduc
Published on
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Space is full of surprises. Sometimes we come across planets in the shape of a rugby ball, other times it offers us rare sights, such as aurora borealis in unusual places, two planets (Mercury and Venus) giving the impression of touching each other, or comets, visible from our garden and with the naked eye.
But it can also be threatening. Proof by information: Alain Maury and Georges Attard, two French amateur astronomers, specialists in asteroid hunting, spotted 2023 DW and transmitted their observations to the International Astronomical Union, which interested NASA.
It is common for celestial bodies to pass close to us, as in December 2022 with 2015 RN35, or 1994 PC1, barely a month later. But there, this asteroid of about fifty meters in diameter would have a (small) chance of crashing on Earth in 2046.
Armageddon in 2046 ?
“Don’t worry, it is common for asteroids to appear, at first, more dangerous than they really are,” reassured the European Space Agency (ESA), on Twitter.
And that, to be threatening, 2023 DW really is. With a size of 49.23 m, precisely, it spins at a speed of 24.63 km/s. “In comparison, the other asteroids move at speeds between 12 and 20 km / s”, recalls Gilles Dawidowiczvice-president of the Astronomical Society of France (SAF)contacted by actu.fr. “But comets can go even faster: up to 70 km/s. »
You can simulate the course of the asteroid
Thanks to NASA calculations, the latter has published a simulator on its website. Accessible to this addressit allows you to learn more about 2023 DW, and to view the route it could take.
And even if “it takes several weeks to reduce the uncertainties”, as NASA reminds us on Twitter, scientists have already estimated its orbit over decades. According to them, it is clear, there is a chance that its trajectory will cross ours. Thanks to their calculations, they were able to define a precise date: February 14, 2046.
The European Space Agency goes even further in the estimates and evokes a probability of one chance in 700 for this big stone to fall on our heads.
The vice-president of the SAF also wishes to reassure: “For the moment, we are talking about uncertainties up to millions of kilometers. Nothing is done yet. »
NASA has also ranked 2023 DW No. 1 in its ” risk list“, a classification referencing the celestial objects that could harm Humanity. In fact, an asteroid of this size would not destroy the world, but it would cause a lot of problems.
A shock similar to that of Tunguska?
If this huge stone were to reach the surface of the Earth, it would have serious consequences. Gilles Dawidowicz evokes “an atomic disaster on a regional scale. Let’s say it falls on Rennes, then the whole of Ille-et-Vilaine could be wiped off the map”.
Moreover, this large pebble is not without reminding astronomers of another. In June 1908, a meteorite almost fell in Siberia. It is the event of Toungouska. And the asteroid had exploded 5 to 10 km before hitting the ground. However, the consequences were disastrous: scientists speak of a power equivalent to 1000 times that of the attack on Hiroshima.
More than 2000 km of forests and 60 million trees have been wiped out. The detonation, which caused damage in a diameter of more than 100 km, was heard 1500 km around, the equivalent of a Paris – Stockholm. Fires were born from it and lasted for whole weeks.
The estimate of the size of what caused all this: several tens of meters.
Dart: a weapon against asteroids
But the situation has changed in recent months. We now have a weapon against asteroids. In November, NASA sent the Dart probe, 600 kg for 1 m3 (not counting the solar panels) crashing into Dimorphos, 163 meters in diameter. The objective: to deviate the trajectory of this (very) large stone (which in no way threatened the survival of Humanity. The Dart mission was launched as a test, to see if it could work).
And it was a huge success: Dimorphos’ orbit was reduced by 32 minutes. Even though it would have “already been a success to reduce by 10 minutes”, as Bill Nelson, head of NASA, explained at the time.
NASA has proven that we are serious as defenders of the planet.
“There, it will accelerate”, enthuses Gilles Dawidowicz. “But nothing has been done yet, we have to be very precise and refine the calculations. Only time will allow it, ”he tempers directly. Indeed, Dimorphos is three times larger than 2023 DW.
Do not panic, therefore, but be careful all the same.
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