(C) Daily Kos
This story was originally published by Daily Kos and is unaltered.
. . . . . . . . . .



Update on Asteroid 2024 YR4 [1]

['This Content Is Not Subject To Review Daily Kos Staff Prior To Publication.']

Date: 2025-02-22

In my last update on potential city-killer space rock 2024 YR4 earlier this week, it had just set a new record on the Torino Scale of impact hazards from near-Earth asteroids and comets, with a probability estimate of 3.1% that it could strike our planet on Dec 22, 2032, surpassing the old record of 2.7% set by 99942 Apophis clear back in Dec of 2004 when it looked like it might have a too-close encounter of the bad kind on April 13, 2029.

Subsequent observations quickly ruled out any potential collision either in 2029 or in later close approaches in 2036, 2051, or 2068. This was quite fortunate in that it is a couple orders of magnitude larger than 2024 YR4 (450 meters by 170 meters in size versus 40-90 meters) and could have caused “unprecedented regional devastation for a land impact or the threat of a major tsunami for an ocean impact” — easily the worst “natural” disaster in at least the last 10,000 years, and why it briefly rated a ‘4’ on the Torino Scale compared to 2024 YR4’s ‘3’.

For “fans” of Giant Meteor 2032, I’m afraid I’ve got some bad news, in that subsequent observations this week have now reduced the possibility of a collision back well under 1% (0.36% to be precise, as of today’s report). We’re not entirely out of the woods yet, but unless further observations unexpectedly show an increase in that probability again over the next few weeks, we can all express a sigh of relief at this point (or disappointment if that’s how you roll?) in having dodged another cosmic bullet — even if it was just a .22 compared to Apophis’ bunker-buster-bomb level of potential damage.

For the mathematically inclined, the closest approach calculation on Feb 18 (when the probability of a collision in 2032 reached 3.1%) was still 123,000 km (about 1/3 the distance to the Moon), with a “3-sigma” error bar of +/- 458,000 km based on a total of 370 observations around the world dating back to late Dec. By comparison, today’s probability estimate of 0.36% is based on a closest approach calculation of 220,000 km with an error of +/- 275,000 km, resting on a total of 404 observations.

And speaking of the Moon, while it is on the opposite side of the Earth on Dec 22, 2032 when 2024 YR4 is still approaching our planet (and thus offers us no possible protection whatever), it turns out there is now about a 1% chance that the errant asteroid could slam into our cosmic partner on its way back out to interplanetary space — which would be about 16:01 +/- 5 hours on Dec 22. Quoting from wikipedia:

The effects of the collision could create an impact crater 500 to 2,000 meters (0.3–1.2 miles) wide on the lunar surface, releasing about 5.2 megatonnes of TNT (21.8 PJ) of energy if it were to impact the Moon at a velocity estimated to be 13.9 km/s (8.7 mi/s), an explosion about 300 times more powerful than the Hiroshima bomb. The potential impact zone extends from just south of Mare Crisium, a solidified lava plain, to Tycho, an ancient crater, all located on the visible side of the Moon. Michael Busch of the SETI Institute, notes that an explosion on the Moon "would be very obvious to any spacecraft observing from lunar orbit" but may not be as visible to the unaided eye from Earth due to the Moon's brightness. However, other astronomers believe the impact could be visible from Earth. Gareth Collins suggested that "the impact flash of vaporized rock would be visible from Earth, even in the daytime", while Daniel Bamberger of the Northolt Branch Observatories in London stated that the impact "could be brighter than the full moon" making it clearly visible to the naked eye.[34][35]

So all is not lost quite yet for those still hoping to witness a cosmic collision from a relatively safe distance, though we might want to rethink actually being on the Moon come Dec 22, 2032 unless that risk also drops back down under 0.1%.

[END]
---
[1] Url: https://www.dailykos.com/stories/2025/2/22/2305523/-Update-on-Asteroid-2024-YR4?pm_campaign=front_page&pm_source=more_community&pm_medium=web

Published and (C) by Daily Kos
Content appears here under this condition or license: Site content may be used for any purpose without permission unless otherwise specified.

via Magical.Fish Gopher News Feeds:
gopher://magical.fish/1/feeds/news/dailykos/