This placing picture from the science digicam on ESA’s Jupiter Icy Moons Explorer (Juice) exhibits interstellar comet 3I/ATLAS spewing mud and fuel. The tiny nucleus of the comet (not seen) is surrounded by a shiny halo of fuel often known as the coma. A protracted tail stretches away from the comet, and we see hints of rays, jets, streams and filaments.
The inset within the picture exhibits the identical knowledge, however processed to focus on the coma construction. The arrows within the high left point out the path through which the comet was transferring (blue) and the relative path of the Solar (yellow). Whereas 3I/ATLAS is a customer from interstellar area, travelling from exterior the Photo voltaic System, its behaviour is totally in keeping with that anticipated from a ‘regular’ comet.
The digicam, named JANUS, took this picture on 6 November 2025, simply seven days after the comet made its closest strategy to the Solar. On the time, Juice was about 66 million km away from the comet.
All through November, Juice used 5 of its science devices to watch 3I/ATLAS – JANUS, MAJIS, SWI, PEP and UVS. Collectively, they collected data that can reveal how the comet was behaving and what it’s made from.
In the course of the months that adopted the observations, Juice was on the alternative aspect of the Solar to Earth. It was utilizing its most important high-gain antenna as a warmth protect, and its smaller medium-gain antenna to ship again knowledge to Earth at a decrease charge. This meant that instrument groups needed to wait till final week to obtain the information; they’re now working arduous to analyse them.
In complete, JANUS took greater than 120 pictures of 3I/ATLAS throughout a big wavelength vary. The instrument group is taking a more in-depth have a look at all these pictures to grasp what they reveal in regards to the comet.
In the meantime, the MAJIS and UVS groups are busy learning spectrometry knowledge, these behind SWI are investigating knowledge on the comet’s composition, and the PEP group is digging into particle knowledge. Along with the ESA group engaged on Juice’s navigation digicam, which additionally photographed 3I/ATLAS, they may all come collectively in late March to debate their findings.
Science is sluggish, however because the devices groups at the moment are all-too-aware, good issues come to those that wait. Keep tuned for an replace from us.
For the most recent updates and FAQs associated to comet 3I/ATLAS, see esa.int/3IATLAS.
JANUS is a multicolour optical digicam designed to take detailed, high-resolution images of Jupiter and its icy moons. It was developed by an industrial consortium led by Leonardo SpA, beneath the supervision of the Italian Area Company (ASI) and in collaboration with the Italian Nationwide Institute for Astrophysics (INAF), which is chargeable for instrument science, the German Aerospace Heart (DLR), CSIC-IAA in Granada (Spain) and CEI-Open College in Milton Keynes (UK).
[Image description: A white, glowing egg-shaped object lies in the centre of the black-and-white image, on a dark, starry background. Glowing streaks spread upwards from the object. In the top left, a yellow arrow marked ‘Sun’ points straight down, and a blue arrow marked ‘Velocity’ points towards the 7 o’clock direction. In the bottom left, an inset shows the same object on a lighter grey starry background, filled with ragged-edged, concentric egg shapes gradiented black-to-white.]
