Summary
NASA has lowered the estimated risk of asteroid 2024 YR4 striking Earth in December 2032 to 1.5%, down from 3.1% a day earlier. The European Space Agency’s (ESA) estimate stands at 1.38%.
The asteroid, 40-90 meters wide, could cause significant city-level destruction but not a global catastrophe.
The projected impact corridor spans the Pacific, South America, Africa, and South Asia.
NASA also estimates a 0.8% chance of the asteroid hitting the Moon.
It’s probably not big enough to shatter the moon, but enough to at least alter its orbit. I’m not enough of an astrophysicist to say how much. I haven’t looked up the forces involved, so I can’t even give a ballpark estimate.
It technically would alter the moons orbit, but not by a lot. This asteroid would impact with roughly the energy of a nuclear bomb, which sounds like a lot, but on the scale of our moon it’s negligible.
A rough estimation given my limited understanding of physics is that to change the moon’s orbit by 1 m/s, you would need to impart something like 10²² joules of energy into it. Wikipedia says that if this asteroid hits the moon, the impact energy will be around 10¹⁶ joules. I don’t know how much you know about exponents, but 10¹⁶ is approximately 0% of the way to 10²², and that’s just change of 1 m/s
Of course, someone who actually understands physics is free to correct me if I’m wrong