THE’Asteroid 2024 YR4discovered the December 27, 2024 from the collaboration atlas, it is a small body of the solar system of 40-90 metersbut he is making a lot of talk about himself because of his relatively high probability of hitting the earth in almost 8 years, the 22 December 2032: just two weeks ago the astronomers of the ESA, the European Space Agency, calculated a possibility of impact of the1.2%while the latest calculations go up this number to 2%one of the highest ever calculated for an asteroid. At the moment the asteroid – which will also be observed by the powerful from next month James Webb Space Telescope Della Nasa – places a risk 3 on Turin scale (which goes from 0 to 10) for the possibility of impact with an asteroid Near-Earth.
The most striking case in this sense is that of Apophisasteroid that at the time of its discovery (in 2004) had a probability of impact of well 2.7%. Then, with the advent of increasingly precise data, Its probability of impact has dropped to 0 For at least a century.
The affair of Apophis should be warned on the fact that a recently discovered asteroidas is currently 2024 YR4, can have a rather high estimated probability of impact, and indeed It is not unusual that at first increases To then collapse until they reach practically zero. Most likely the same thing will also happen to 2024 YR4, yet they are reading these days unnecessarily alarmistic titles As is the tradition now for the most hungry press of clic. We therefore clarify why the chances of impact between 2024 YR4 and the earth are increasing, and why this it must not worry in any way.
When you discover a new asteroid, the first thing you want to establish is its exact orbit around the sun. Especially if this asteroid is located near the earth, we are particularly pressed to know if there are Possibility of a collision in a more or less close future. Incidentally, an asteroid of the size of 2024 YR4 could destroy an area as large as a metropolis if he were to hit our planet. But how do you establish the orbit of an asteroid?
I explain it to you with a practical example: there is a gentleman who walks on the street, and you want to predict where he is going. What do you do? Simple: observe how its position varies over timestep by step, until you guess what his journey could be. The same with an asteroid: astronomers observe him patiently, night after night, gradually marking his position in the sky, and as they collect the different positions “They unite the dots” In accordance with the laws of physics to establish its path.
Now, what happens as astronomers collect more and more data? Initially the “dots” available are very few, so there are many possible orbits with the data collected. In other words, The uncertainty about its orbit is very large. Returning to our example, if the guy we are observing is turning right at the crossroads maybe he has to go to get the bus to the stop around the corner, or maybe because he is going to the mail just further, or perhaps because he wants to jump to supermarket at the end of the road. But when we observe that it is moving away from the shelter, we can certainly exclude the “Take the bus” option. And when we excluded this option, what happens to the chances of the “mail” option and the “supermarket” option? Exact, increase.
The same thing happens with asteroids. More we collect data on the positions of an asteroid over time, the more the possible orbits that we are able to exclude are. And the more orbits we exclude, the more those that remain appear likely in proportion. In other words, as the uncertainty about the orbit decreases The probability of the passage on a specific between the “surviving” points increases. In the graph below, made by ESA, there is clearly the decrease in uncertainty on the distance of maximum approach to the land scheduled for December 22, 2032.
But how does this uncertainty translate? The European Space Agency itself shows it in this image:
As you can see, the asteroid can hit us in full, but it can very well dodge us in total safety. The relative probability of the impact increases as the red dots are reduced (i.e. as the uncertainty is reduced in the orbit of 2024 YR4), but the possibility that the celestial body passes into one of the many distant red dots From the earth they are much higher than the possibility that the asteroid enters the collision course with our planet. Therefore, statistically it is very likely that in the end the “correct” dot will not be the one who coincides with the earth, but with one of the others who they will not involve any danger for us.
This happens very often with asteroids with orbit close to the terrestrial one: we discover them, we immediately calculate a small probability of impact, we observe them for some time, initially the probability grows and then slowly decreases as the orbit is calculated with more and more precision.
The Asteroid 2024 YR4, which is now moving away from us, can still be observed until Mayafter which it will become too weak to be still visible from the earth to 2028the year of the next approach to the earth, when telescopes will be able to go back to pointing this little heavenly pebble to know him more and more deeply.
