Object 3I/ATLAS may be partially destroyed today by solar plasma impact

This afternoon, according to calculations, the object 3I/ATLAS will have to withstand a blow from one of the largest plasma clouds in the 25th solar cycle, ejected by the Sun in the direction of the comet on the night of October 21-22. There is a high probability that this will be the first such test in the life of a celestial body, with consequences that are not fully understood.

Unlike internal comets of the solar system, which orbit the Sun and repeatedly approach it during their life, 3I/ATLAS is not tied to any star and moves freely within the Galaxy. Given the low density of stars, a close encounter with any of them, at a mere 200 million km (about 10 light-minutes) by galactic standards, is an extremely rare event and may never have occurred before in the body's lifetime. Furthermore, flare activity is characteristic not of all stars, but only of certain types, including our Sun. Finally, the very fact of an exceptionally large plasma ejection during a stellar wanderer's closest approach to a randomly encountered star is quite unlikely. For all these reasons, it is quite possible that the object will be subjected to such an impact today for the first time in its life, with subsequent exposure to a cloud of dense plasma for 1-2 days. The consequences of the impact are unclear. Plasma ejections often tear off the tails of comets but leave their rocky cores intact. At the same time, the mere presence of a rocky core is not a requirement for a comet, as some may be a loose snowball or even simply a clump of sand and dust pulled together by gravity. It's possible that comets of this type orbiting the Sun simply didn't survive to this day in significant mass, and the surviving "solid" comets are the exception to the rule. The precise nature of 3I/ATLAS's core, hidden within the gas and dust cloud, is, strictly speaking, not fully understood. Its size, according to some estimates, is less than 1 km, and it's impossible to see it in principle. Spectroscopic methods allow us to draw some conclusions about the comet's chemical composition, but provide almost no information about the physical state of the core. It can be noted that, in some scenarios, the impact of solar plasma may, conversely, stimulate an increase in the body's brightness due to a pulsed increase in the rate of outflow of volatiles from the comet's central regions. It is possible that the object will eventually appear on the LASCO images, where it is currently hidden.

Of course, those who believe that a space probe is hidden inside the gas and dust cloud will find this reasoning meaningless. In this system, the primary question is whether the spacecraft's creators even foresaw the possibility of it being hit directly by stellar flares, and whether the probe's radiation shielding would withstand the exceptional power of the event and the fact of a direct head-on impact.

It will be impossible to observe the comet's passage through the cloud or even simply find out the object's condition after the impact in the coming days. As already noted, the body is currently fundamentally inaccessible to observation from Earth.