Early this month, the chances had risen to 1.9 percent. A few days later, they were 2.3 percent. Those were the happy, carefree times.
My old pal Chicken Little (I’m happy to overlook Chicken’s madcap optimism) is looking both anxious and smug as I write. The chances of a close encounter of a most unpleasant kind with Asteroid 2024 YR4 have risen again. When it was first spotted in December there was a 1.6 percent chance it would hit the Earth just before Christmas 2032. When I first posted on this troublesome rock early this month, the chances of this had risen to 1.9 percent. When I posted again a few days later, they were 2.3 percent.
Those were the happy, carefree times.
Astronomers on Tuesday said that the asteroid designated 2024 YR4 had become the most likely sizable space rock ever forecast to impact planet Earth. The object, first detected in December, is 130 to 300 feet long and expected to make a very close pass of the planet in 2032. Its odds of impacting Earth on Dec. 22 of that year currently stand at 3.1 percent.
That exceeds the threat once posed by Apophis, a much larger asteroid that was discovered in 2004. Astronomers initially calculated its chances of hitting Earth in 2029 at 2.7 percent. Further observations of Apophis reduced the odds of an impact at any time during the next century to zero. But the prospect was, for a time, unsettling.
The good news is that 2024 YR4 (which needs a catchier name), unlike the much larger asteroid that saw off the dinosaurs (making way for us, thanks!), does not threaten an extinction-level event. The bad news is that it’s large enough to count as a potential “city-killer.”
The Times lists various different types of damage 2024 YR4 could cause, which depends on, among other factors, its density, size (130-300 feet is still quite a range) and what it’s made of (mostly iron would be worse than stony). It matters whether it explodes in the air or crashes into the ground, and, obviously, it matters (a lot!) where this happens. Many of the most likely impact sites are in the ocean, but, as things currently look, there’s a chance 2024 YR4 could land or explode near any one of a number of large cities including Bombay, Lagos, or Bogota, conceivably with devastating effect.
NBC reports that China’s State Administration of Science, Technology and Industry for National Defense (SASIND), which among other responsibilities supervises the country’s space activities, has posted three vacancies (coincidence?) for “a planetary defense force to combat the threat of asteroids colliding with Earth.” The actual jobs are less glamorous than that suggests (research; no walking in slow motion towards the spacecraft that will save us all), and the requirement that, in addition to the necessary scientific qualifications, the recruits should “maintain a firm political stance” in line with Xi Jinping shows a poor setting of priorities.
Nevertheless, it’s good that China appears to be taking the asteroid menace seriously. When it comes to dealing with this problem, the more the merrier.
NBC:
In 2027, China is planning an asteroid-deflection test akin to the double asteroid redirection test successfully carried out by NASA in 2020. The Chinese test will be conducted on an asteroid called 2015 XF261, which is smaller than the 525-foot Dimorphos asteroid whose trajectory NASA disrupted by crashing a spacecraft into it.
If the odds don’t improve (for us) they should perhaps hold that test off until 2028, the next time 2024 YR4 will be in these parts, as a plan B might be helpful if NASA is unable to pull off a second successful DART mission. Then again, there’s a decent argument that giving 2024 YR4 a modest DART-style nudge may not be enough. Something more destructive may be required.
The probability is still only 3.2 percent, but I hope NASA (and SpaceX) are giving this some thought.