The radio interferometer ALMAin Chile, found that the comet 3I/ATLAS releases copious amounts of methanol (CH3OH) e of hydrogen cyanide (HCN), molecules involved in the synthesis of amino acids and nucleic acids and therefore necessary for the construction of the “fundamental bricks of life” as we know it. This supports the theory according to which it may have been very ancient objects like 3I/ATLAS that had brought life to Earth billions of years ago.
But this is not the latest news on the third interstellar visitor we have discovered transiting our Solar System. In addition to ALMA observations carried out between August and October, we have new images obtained in November by JUICE probe (Jupiter Icy Moons Explorer) of the European Space Agency (ESA) and by space telescope Hubble of NASA.
All this happens while we await the passage of the comet to the point of closest proximity to the Earth expected for December 19th.
What does the presence of methanol and hydrocyanic acid imply: ALMA data
Not yet peer-reviewed research, led by NASA Goddard Space Flight Center astrochemist Martin Cordiner, used millimeter-band data from the ALMA telescope over the Chilean Andes to study the chemical composition of 3I/ATLAS. Observations conducted between late August and early October show that 3I/ATLAS possesses large quantities of methanol and hydrocyanic acid. The exceptional nature of this discovery lies in the fact that these molecules serve to obtain i fundamental building blocks for life as we know it on Earth, thus suggesting that comets like 3I/ATLAS may have helped bring the ingredients necessary for life to Earth.
Research shows how both methanol and hydrogen cyanide they come from the rocky core of 3I/ATLASwith the methanol appeared in significant concentrations even in the hair of the comet. Ben 8% of the gaseous material ejected by the comet is made up of methanolabout four times more than comets in the Solar System. The same abundance of methanol and hydrogen cyanide is among the highest ever measured for a comet. In fact, the authors underline how molecules such as hydrocyanic acid and methanol are present in trace amounts and not as dominant constituents of our comets, which adds another piece to the peculiar puzzle of 3I/ATLAS.
What can be seen from the new Hubble image of comet 3I/ATLAS
The Hubble Space Telescope was one of the first to set its “eyes” on the interstellar comet 3I/ATLAS in July, a few weeks after its discovery. Hubble has the news these days re-observed 3I/ATLAS on November 30, when the comet was at 286 million km from Earthfinding it different from the first observation since it is now in full operation following the passage at the point of maximum proximity to the Sun. The observations were conducted using the F350LP filter of Hubble that covers the entire optical spectrum (what our eyes are sensitive to) to maximize the amount of light collected by the comet. The long exposure photo at the top of the article was taken with 3I/ATLAS always in focus, which produced the streaking effect of the “fixed” stars around the comet. Hubble will make more observations of the comet in the coming months, before this object moves away towards the outskirts of the Solar System and is then lost forever in interstellar space.
Details of the close encounter between the comet and the JUICE probe
There JUICE probe of ESA, traveling to Jupiter to study its icy moons, had a privileged point of view to study 3I/ATLAS, passing only 66 million km from the comet at the point of closest approach to the November 4. The probe aimed all 5 scientific instruments on board towards the comet, collecting behavioral information of the comet and on his composition. The image below, in particular, was obtained through the Navigation Camera (NavCam) of the probe, an instrument that is not designed to take these types of photos, but rather for navigation in the Jovian system.
The photo was taken on November 2when the comet was at a distance of 70 million kmand shows the bright halo of gas surrounding the comet, the hair and well two tails. The first, the one at the top, is there plasma tailcomposed of electrically charged gas that is pushed in the direction opposite to the Sun by the solar wind, while the one at the bottom left is the weak dust tailcomposed of tiny solid particles rising from the cometary surface.
This image is just a quarter of the entire Navcam image. The data of all instruments are still downloadingwith completion expected between 18 and 20 February 2026. The delay is due to the fact that Juice is currently using its main high-gain antenna as a heat shield to protect itself from the Sun, while letting its smaller, medium-gain antenna send data to Earth at a much slower rate. Although it is only partial, this image is already better than those taken by ESA probes around Mars, which despite being closer to Juice’s comet, have observed the object when it had a lower degree of activity since further from the Sun.
