The latest analysis from the European Space Agency (ESA) Planetary Defence Office has reduced the probability that asteroid 2024 YR4 might impact Earth in 2032 to 0.001%.
Risk in this sense is a statistical term for the probability of something undesirable happening. So the risk decreased even though the steroid didn’t actually change its track. What changed is our measure of the odds of the impact.
The expectation value was huge at one point: a few percent probability of hitting the planet multiplied by the enormous cost of it hitting the planet (in terms of life and money and environmental damage).
The damage caused by an impacting asteroid depends greatly on the exact size and composition of the asteroid. The exact size of 2024 YR4 is still uncertain, but an airburst is a likely scenario for its size range. If the asteroid were to enter the atmosphere over the ocean, models indicate that airbursting objects of this size would be unlikely to cause significant tsunami, either from the middle of the ocean or even nearer shore.
If the asteroid entered the atmosphere over a populated region, an airburst of an object on the smaller side of the size range, about 130 - 200 feet (40 - 60 meters) could shatter windows or cause minor structural damage across a city. An asteroid about 300 feet (90 meters) in size, which is much less likely, could cause more severe damage, potentially collapsing residential structures across a city and shattering windows across larger regions.
No longer poses “significant impact risk”?? It never did!!
Risk in this sense is a statistical term for the probability of something undesirable happening. So the risk decreased even though the steroid didn’t actually change its track. What changed is our measure of the odds of the impact.
Yeah, I know. But the risk was never “significant”.
The expectation value was huge at one point: a few percent probability of hitting the planet multiplied by the enormous cost of it hitting the planet (in terms of life and money and environmental damage).
The asteroid is way too small to pose a significant risk unless it hit a city - which would have been evacuated months before the asteroid hit.
Significant economic and cultural damage for the affected country? Sure.
See this FAQ from NASA:
i think they meant “risk of a significant impact” rather than “significant risk of an impact”.
It was what, 1 or 2 percent probability of hitting, and the region in which it could hit included things like a densely populated city.
I wouldn’t call that insignificant, insignificant would be 1 in 100,000 chance of hitting the planet, vs 1 in 100. That’s dangerous.
Phew!