Thanks to the observations made with the space telescope James Webb It has been discovered that the asteroid Near-Earth 2024 YR4 It is “of class tunguska” with dimensions of about 60 metersand we also obtained other information on this body of the Solar System as its albedo (ability to reflect light) and its orbital parameters.
The asteroid had jumped to the honors of the news in recent months because it initially had a relatively high probability of crashing on earth the 22 December 2032: now we are sure that the asteroid it does not represent any threat to the earthbut currently has a probability of 3.8% to hit the moon on 22 December 2032 according to Cneos (Center for Near-Earth Object Studies) NASA. This number It is not written in the stone: changes and updates as it is collected new data on the orbit of the asteroid. The calculated probability that affected the earth had in fact initially increased and then decreased to go down to zero, as often happens in these cases.
A possible impact of 2024 YR4 with the moon would not have no influence on earth. Indeed, the opportunity that the asteroid crashes on the moon is of great interest for astronomers because it would allow to study “in real time” How lunar craters are formed And how the regolite of our natural satellite behaves in case of impact.
Will the Asteroid 2024 YR4 hit the moon? We don’t know, but there are no risks for the earth
The possibility that the asteroid can enter the collision course with the moon it is not new: astronomers began to ventilate the hypothesis still when an impact with the earth was not excluded. At the end of February – therefore once certain that 2024 YR4 would not have struck us – the Cneos estimated at the1.7% The chances of impact of the asteroid with the moon on 22 December 2032. The probability is now more than doubled, coming to 3.8% Also thanks to the recent observations of the space telescope James Webb. A 3.8% probability is relatively high for an asteroid Near-Earth Like 2024 YR4.
At the moment we cannot know if this value will grow or decrease until it completely excludes an impact as it happened in the case of the earth. To find out something more We should wait next month: At the moment the celestial body is moving away from the earth and from mid -April it will be too little bright to be observed.
According to what we know about the asteroid today, if this should crash on the moon could create a impact crater with a diameter of 1.5-2 km.
The dimensions calculated thanks to James Webb: the asteroid is “of class tunguska”
Thanks to the repeated observations of the Asteroid we had the opportunity to get to know its orbit better, but the doubt remained on its size. This factor is fundamental to get to know this celestial body better and evaluate the effects of a possible impact. James Webb space telescope was called to observe this celestial body in near and medium infrared Just for this purpose.
Why the James Webb? The problem with asteroids is that they are too small in order to be able to measure its dimensions directly. What you do is therefore measure the amount of sunlight that the asteroid reflects and, on the basis of this value, indirectly trace to the dimensions once its reflectivity is known. If we do it only with visible light we have rather large margins of uncertainty: the previously estimated dimensions were in fact from 40 to 90 meters.
The infrared skills of James Webb have made it possible to drastically reduce this uncertainty: thanks to the data of the NASA space telescope, today we know that 2024 YR4 has a diameter of 60 meters with an uncertainty of 7 meters. It is therefore an asteroid “Tunguska class”that is, it has comparable dimensions to the celestial body that the June 30, 1908 caused the violent Tunguska eventin which a violent explosion at high altitude due to a large meteor knocked 80 million trees near the Tunguska river in Siberia.
