NASA, ESA Reveal Interstellar Comet 3I/ATLAS' Heightened Activity Ahead of December 19 Earth Encounter; Largest Object Surges Toward Sun

New images of the interstellar comet 3I/ATLAS reveal heightened activity as it approaches its closest encounter with Earth on December 19, 2025. The comet, identified as the third confirmed interstellar object in the solar system, has been observed by NASA and the European Space Agency (ESA) using advanced imaging technologies. These observations highlight the comet's dynamic behavior, including the emission of gas and dust tails, as it accelerates through the inner solar system at approximately 130,000 mph [according to NASA and ESA observations](https://www.livescience.com/3i-atlas-comet-activity).

Hubble Captures High-Resolution Images

NASA's Hubble Space Telescope has provided a detailed view of 3I/ATLAS, captured on November 30, 2025, from a distance of 178 million miles. The image shows the comet's nucleus and coma—a glowing atmosphere of gas and dust—while background stars appear as streaks due to the telescope's tracking of the fast-moving object. The data suggests [increased sublimation of ice](https://www.livescience.com/3i-atlas-comet-activity), a common phenomenon as comets near the sun, with solar radiation pushing gas into a visible tail.

Juice Provides Teaser of Activity

ESA's Jupiter Icy Moons Explorer (Juice) captured a navigation camera image of 3I/ATLAS on November 2, 2025, just days after its closest approach to the sun. The image reveals a bright coma and hints of two distinct tails: a plasma tail composed of charged gas and a fainter dust tail. Juice's scientific instruments, which collected data on the comet's composition and behavior, are expected to deliver full results by February 2026. The delay is attributed to Juice's use of a smaller antenna for data transmission while protecting its main antenna as a heat shield [according to ESA reports](https://www.esa.int/3IATLAS).

Preparing for Earth's Close Encounter

As 3I/ATLAS approaches Earth, the James Webb Space Telescope is set to conduct further observations. Ground-based observatories and amateur astronomers will also monitor the comet, which is expected to reach its closest point to Earth at approximately 170 million miles. Scientists emphasize the importance of these observations to understand the comet's origins and composition, given its interstellar trajectory. The comet's size, [estimated between 1,400 feet and 3.5 miles](https://www.livescience.com/3i-atlas-comet-activity) in width, makes it the largest interstellar object observed to date.