Astronomers have unveiled spectacular new images of the interstellar comet 3I/ATLAS, showcasing its remarkable double tail. Captured by both the European Space Agency (ESA) and NASA, these images reveal the chaotic surface of this cosmic visitor, which is currently on a trajectory towards its closest approach to Earth on December 19, 2023.
Since its discovery in July, 3I/ATLAS has attracted significant attention from observatories worldwide. Researchers have been eager to study this rare cosmic object, as it is only the third known interstellar object to pass through our solar system. As the comet approaches, scientists are utilizing both the Hubble Space Telescope and the ESA’s Jupiter Icy Moons Explorer (Juice) to gather essential data on its composition and trajectory.
The latest imaging efforts have provided vital insights into the comet’s physical characteristics. The images reveal a distinct coma—a glowing halo of gas—and two separate tails. One tail, composed of electrically charged gas, is identified as a plasma tail, while the other is a fainter dust tail formed by solid particles released from the comet’s surface. This dual tail phenomenon provides a unique opportunity for researchers to understand the processes occurring as the comet interacts with solar radiation.
As 3I/ATLAS neared the sun in October, the intensity of sublimation increased, resulting in the release of various gases. This solar encounter has significantly enhanced scientists’ understanding of the comet’s makeup. Hubble’s initial observations provided a detailed view of the comet’s teardrop shape, laying the groundwork for ongoing imaging campaigns.
On November 30, Hubble once again focused its Wide Field Camera 3 on 3I/ATLAS. Despite the comet being approximately 286 million kilometres (178 million miles) from Earth, Hubble succeeded in capturing even clearer images of the celestial body. Concurrently, the Juice mission, currently en route to study Jupiter and its icy moons, was ideally positioned to observe the comet from approximately 66 million kilometres (41 million miles) away in early November.
The Juice mission employed five scientific instruments and the onboard Navigation Camera, or NavCam, to examine 3I/ATLAS. To minimize the wait for critical data, the team downloaded a quarter of a single image taken by NavCam, which revealed heat-driven activity linked to the comet’s solar proximity. The initial findings indicate significant activity, furthering the understanding of the comet’s behavior.
Retrieving high-quality images from Juice has proven challenging due to its distance and current operational constraints. The spacecraft is utilizing its main antenna to shield its sensitive instruments from solar radiation, limiting data transmission capabilities. Most of the flyby data is expected to arrive on Earth between February 18 and 20, 2024, which will include high-resolution images that may help clarify the origins of this interstellar object.
3I/ATLAS is projected to pass within 167 million miles (270 million kilometres) of Earth on December 19, but experts assure that it will be on the far side of the sun during this close approach and will not pose any risk to our planet. For context, Earth is situated about 93 million miles (150 million kilometres) from the sun. According to NASA, the comet is expected to remain visible to telescopes and space missions for several months before exiting the solar system.
While the observations of 3I/ATLAS offer an exciting glimpse into interstellar phenomena, the Juice mission has a broader objective. Launched in April 2023, the spacecraft’s primary goal is to investigate whether Jupiter’s three largest moons—Ganymede, Callisto, and Europa—could potentially support life. Juice is not scheduled to arrive at its destination until July 2031, where it will search for subsurface oceans beneath the icy surfaces of these moons.
As the study of 3I/ATLAS progresses, scientists remain committed to unlocking the secrets of this rare interstellar visitor while simultaneously preparing for the long-term exploration of Jupiter’s intriguing moons.
