Purdue Professor Explains Why the Odds of Asteroid Hitting Earth Changed
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STATEWIDE–The odds of the 2024 YR4 asteroid hitting Earth in 2032 have gone from a little more than 3% to now 0.0004%.
Brandon Johnson is a professor of Earth, Atmospheric, and Planetary Sciences at Purdue University.
“The asteroid was only detected about two months ago. And so it’s a very, very new asteroid. And when it’s first detected, the orbit is not known very well. And we have this big region of uncertainty, and the Earth is, you know, the Earth’s in that region of uncertainty. And we have a small chance of it hitting the Earth. Then as we get more observations, that region of uncertainty shrinks a bit. And the Earth was still in that region of uncertainty after it shrunk. So that means the probability of an impact go up. But then we got even better observations and it shrunk more. And now the Earth really right at the edge of that uncertainty, which means that the probabilities shrunk way down to less than a fraction of a percent,” said Johnson.
Johnson said astronomers don’t know of any other asteroids expected to hit Earth over the next 100 years.
“But it is really important to track them. And so we know that asteroids do hit the Earth from time to time. So, for example, a car sized asteroid will hit the Earth about every year, and those ones are too small that we really don’t know about them before they happen, but they don’t really do much damage. Something like 2024 YR4, that kind of asteroid will hit the Earth about every thousand years. That’s something about half the size of a football field. Or maybe even a little bit bigger,” said Johnson.
Johnson said it’s not only fascinating to study asteroids, but also important to do so.
“So, there’s lots of reasons why it’s important to study asteroids. I think one of the main reasons is these represent some of the first solids in the solar system. So we can learn about how our planets were made and all kinds of cool things about our solar system, from asteroids, from the safety side, as we understand asteroids better, we can better understand how we might deflect or destroy these asteroids. And then on top of that, we really want to detect as many of these asteroids as possible. And so there’s two really cool things happening very soon. We have the Rubin Observatory that’s funded by the NSF and DOE that’s coming online in the summer. And then we also have NASA’s NEO surveyor. That’s a mission that’s going to detect many of these small, potentially hazardous asteroids. And so if we have a much better idea of how many of these asteroids are out there, we can actually defend against them,” said Johnson.
The Moon, however, could be in 2024 YR4 asteroid’s path. NASA’s latest numbers show there’s a 1.7% probability that it could impact the Moon.
