Astronomers capture rare interstellar comet 3I/ATLAS near Mars

In a significant astronomical event, scientists from the European Space Agency (ESA) captured images of the interstellar comet 3I/ATLAS as it approached Mars, with the observation occurring on October 3, 2025. This rare comet, notable for being only the third confirmed interstellar object entering our solar system, was located approximately 18,641,135 miles from Mars when the images were taken. The event took place using two of the ESA’s Mars orbiters, ExoMars and Mars Express, which are primarily designed to study the Martian landscape. The observations were particularly challenging for the cameras on the orbiters due to the comet's faintness, which is estimated to be around 10,000 to 100,000 times dimmer than their typical targets. As a result, scientists were uncertain about what to expect when they aimed their instruments at the comet. The capture of this image provided a unique glimpse into the characteristics of 3I/ATLAS, showing its icy-rocky nucleus and a surrounding coma—a fuzzy halo of gas and dust)—which is formed as it passes through the solar system. Discovered on July 1, 2023, in Río Hurtado, Chile, comet 3I/ATLAS has stirred significant interest among astronomers since its discovery. NASA has indicated that this comet could be over 3 billion years older than our solar system, giving it a potential age that far exceeds that of other comets. In addition to its age, the comet is significantly larger than previously anticipated, weighing more than 33 billion tons and primarily composed of carbon dioxide gas and water ice. As it approaches the Sun in late October 2025, the heat and radiation will cause the comet to become more active, releasing gas and dust into space. As researchers continue to analyze data and images from ESA’s orbiters, they aim to gain further insight into the composition and behavior of this rare celestial body. The comet is expected to make its closest approach to the Sun between the orbits of Mars and Earth. Despite being a fascinating subject for scientists, the comet poses no threat to Earth. Observations of 3I/ATLAS will allow scientists to deepen their understanding of interstellar objects and their impacts on the solar system.