…and speaking of negative, overhyped asteroids: the object 2024 YR4 will likely NOT cause a catastrophe. Firstly, the odds were never good to begin with: as of this past week, December 2032 impact odds were ~1.5-2 percent. Which is to say, the odds of NOT hitting are 98-98.5 percent.
Secondly, those were the odds as of this past week. The process of orbit determination is an ongoing process, taking two months to ~3 years. With each new observation on a new night, the orbit is pinned down better. Pinning down the orbit better means decreased trajectory uncertainty for 5.5 years in advance. In other words, we’re still midway through the process of tracking the asteroid, for the purposes of tracking forward to December 2032. As tracking continues, a spread of possible trajectories gets narrower and narrower. As has happened with every previous asteroid of this size, the spread of possible 2032 tracks will likely converge to an off-Earth (that is, non-impacting) track.
Thirdly, asteroid 2024 YR4 is not much of a threat, even if orbit determination eventually concludes that the asteroid trajectory is an impact trajectory. Its size is several tens of meters, to be confirmed. This isn’t a size that would cause all of humanity to be concerned. At this (small) size, a (putative) impact would cause damage in a radius of miles. Not a region, not a continent, certainly not the whole of Earth. Direct damage would be limited to a particular area, like a few counties or small province. One possibility for defense is simply civil defense: inform everyone in that area of that blast radii, and evacuate people directly in the target zone, plus leave or seek good quality shelter in its surrounding zones.
Third-ish-ly, we’re still tracking that (putative) impact zone, which may turn out to be no direct damage zone at all. As of this week, the potential 2032 impacts cover a swath of Earth, based on slight orbital and timing uncertainties. That uncertainty swath ranges from Latin America, through the Atlantic Ocean, and into Africa. Looking at this swath, it is clear: odds are that the impact (if in fact a 2032 impact occurs) will, overwhelmingly, happen in an unpopulated area. The 2032 swath is mostly jungle, desert, mountain, and… Atlantic Ocean. There simply aren’t a lot of people living in the predicted range of impact points. Of course, having a hypervelocity strike occur in the Atlantic may cause a tsunami. But even then, the tsunami would fall upon northern Brazil, west Africa, some Caribbean islands, etc., few of which have densely populated coastal cities. This is the hurricane belt, after all- people have the sense not to put lots of big, vulnerable developments on these coasts.
We are on task. The first order of business is to search for “precoveries”- images taken before, where the asteroid is in frame but hadn’t been recognized at the time. If we can find a precovery image from before late 2024, that would help pin down the orbit of YR4. Pinning down the orbit would likely settle the question of its future track, and potential future risk. Failing that, another lunation (a New Moon, which leaves the skies nice and dark for good astronomical work) will let YR4 advance slightly in its orbit. The additional 3-4 weeks of data will certainly improve the orbit determination, reducing the uncertainty- it’s just a question of how much. Ultimately, the orbits of Earth and YR4 are such that it will swing by us again in 2028. That additional three years- not three weeks- will pin down any significant uncertainty. Tracking the object over a span of nearly four years- not our current five weeks- will shrink the uncertainly and the (putative) 2032 impact zone.
My closing advice: don’t worry about 2024 YR4 until 2028, and possibly never at all (after another New Moon). Our five weeks of tracking results are just too few- not enough tracking to say anything serious about any impacts. If we were to say something firm, it’s… 98-98.5 percent odds of NOT hitting in 2032.