https://www.space.com/news/live/interstellar-comet-3i-atlas-closest-to-earth-flyby-week-dec-18-2025
Discovered on July 1 by the NASA-funded ATLAS telescopes in Chile, 3I/ATLAS is only the third confirmed interstellar object known to have passed through our cosmic neighborhood, following 1I/‘Oumuamua in 2017 and comet 2I/Borisov in 2019. Its trajectory shows that it originated from beyond our solar system and will eventually travel back into interstellar space.
Of course, Avi Loeb has already claimed (once again) that an interstellar comet is an “alien probe.”
And naturally, other astrophysicists immediately refuted him. Again.
It’s fast. REAL fast. So fast that even as it entered the solar system it was traveling the distance from the Earth to the Sun in only a month, and then it began to pick up even more speed (from the Sun’s gravity, NOT from “jets out the back” or whatever else unscientific SF fans say online).
Of course, we can assume that the aliens’ spaceship will detach from it precisely during its approach to Mars, or during its passage through perihelion when we cannot see it. In this case, it will have to slow down by more than 20 km/s.
And even so, this will not help the aliens much, because the trajectory will remain retrograde relative to the direction of the planets’ rotation around the Sun. So, if the aliens who flew to us billions of years ago have a plan that is a little more complicated than becoming kamikaze pilots, they will have to slow down again, spending a lot of energy on it. And the aliens still need to get that energy from somewhere.
So, most likely, we should not expect any extraterrestrial visitors at the end of the year. And we will not be able to admire the interstellar comet itself. By the time it emerges from behind the Sun, its brightness will already be approximately 11 stellar magnitudes, meaning it will be inaccessible even to small amateur instruments, let alone the naked eye.
So, nah. Sorry.
–> LIVESTREAM from 11 p.m. EST December 19th here: https://www.space.com/astronomy/comets/watch-interstellar-comet-3i-atlas-make-its-closest-approach-to-earth-in-free-livestream-on-dec-18
(FWIW, the last two sentences are NOT supposed to be quotes, but wordpress is quite frankly broken.)
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