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A rare visitor from deep space, an interstellar comet known as 3I/ATLAS, recently made a close approach to Mars, offering scientists an unprecedented opportunity to study an object from beyond our solar system.
The European Space Agency’s (ESA) ExoMars Trace Gas Orbiter, circling the Red Planet, captured new images of the elusive comet last week. Released Tuesday, the photos show a faint, fuzzy white dot — the comet’s icy, rocky nucleus enveloped by its glowing coma of dust and gas — against the vast cosmic backdrop.
This marks only the third confirmed interstellar object ever detected entering our solar system, making its appearance a source of intense interest among astronomers and space enthusiasts since its detection in July. While some theories have veered into the realm of extraterrestrial technology, scientific evidence firmly points to 3I/ATLAS being a natural celestial body.
The comet is not a permanent resident. Its trajectory will take it swinging through the inner solar system, reaching its closest point to the sun around October 30. NASA confirms that 3I/ATLAS poses no threat to Earth, maintaining a distance of approximately 170 million miles during its flyby.
Despite the immense distance — roughly 18.6 million miles from the orbiter — the ExoMars Trace Gas Orbiter, a joint mission by ESA and Russia’s Federal Space Agency, focused its cameras on the comet for about a week starting October 1. Nick Thomas, principal investigator for the spacecraft’s imaging system, noted the difficulty of the task. “This was a very challenging observation for the instrument,” he stated, explaining that “the comet is around 10,000 to 100,000 times fainter than our usual target,” which is typically Mars’s surface.
The two other interstellar objects confirmed to have visited our solar system were ‘Oumuamua in 2017 and comet 2I/Borisov in 2019. According to the ESA, “Every planet, moon, asteroid, comet and lifeform in our solar system share a common origin. But interstellar comets are true outsiders, carrying clues about the formation of worlds far beyond our own.”
Astronomers are eager to study the comet’s size and physical properties as it continues its journey. While currently too close to the sun for ground-based observation, NASA expects it to reappear by early December. Multiple space observatories, including the Hubble Space Telescope, James Webb Space Telescope, SPHEREx, Parker Solar Probe, and Transiting Exoplanet Survey Satellite, are slated to conduct further observations in the coming months.
A recent image from NASA’s Perseverance rover on Mars, showing a faint streak of light, sparked online speculation that it might be 3I/ATLAS. However, NASA has not confirmed this, and further details are pending as the agency’s public outreach office is currently closed due to the government shutdown. ESA’s Mars Express spacecraft also attempted observations, with analysis ongoing to identify the comet.