Imagine a mysterious wanderer from another star system darting through our own cosmic neighborhood – and now, thanks to NASA’s clever solar-watching fleet, we’ve unlocked stunning new glimpses of it peeking out from behind the Sun. This interstellar comet, known as 3I/ATLAS, has captured our imagination, and we’re about to dive into the details that make this discovery so thrilling.
NASA’s array of spacecraft dedicated to studying the Sun managed to snap pictures of comet 3I/ATLAS as it slipped behind our star from Earth’s vantage point. This rare visitor originated around a distant star in the Milky Way about 7 billion years ago, giving us a unique chance to examine something born far beyond our Solar System.
Time is truly running out for scientists eager to gather as much data as possible on 3I/ATLAS before it vanishes into the depths of space forever. In October 2025, the comet dipped out of sight behind the Sun, but by late November, it had reappeared in our earthly skies, ready for more observations.
While hidden from direct view, both NASA and the European Space Agency (ESA) redirected their Mars-based rovers and orbiters toward the comet. For instance, ESA’s Trace Gas Orbiter snapped some impressive photos of 3I/ATLAS, which allowed researchers to refine the comet’s path through space with far greater precision. But here’s where it gets exciting – not only did our Mars explorers get in on the action, but a handful of NASA’s Sun-focused missions also stepped up to observe this otherworldly object during its solar adventure.
NASA’s solar fleets have photographed comets before, but this marks the first deliberate attempt by their heliophysics missions – those studying the Sun’s influence on space – to scrutinize a visitor from another stellar system. Their mission was to uncover more about the comet’s dimensions, surface characteristics, and even its chemical composition. And what did they reveal? Let’s break it down step by step.
First up is STEREO-A, NASA’s Solar Terrestrial Relations Observatory, which led the charge from September 11 to October 2, 2025. Designed to monitor solar activity and its effects on the planets, STEREO-A was expected to struggle with the comet’s faintness. But astronomers employed a smart technique called image stacking – essentially layering multiple photos on top of each other to amplify tiny details, much like how photographers blend shots to reduce noise and highlight faint stars in astrophotography. With this method, the spacecraft’s Heliospheric Imager-1, which captures visible light, made the comet visible as a faint white haze surrounded by streaks of black and pink.
Next, NASA’s PUNCH mission – short for Polarimeter to Unify the Corona and Heliosphere – joined the fray. Primarily built to track coronal mass ejections (those explosive bursts of charged particles and magnetic fields from the Sun’s surface), PUNCH’s knack for gazing near the Sun made it perfect for following 3I/ATLAS as it neared our star. Between September 28 and October 10, 2025, when the comet was about 372 to 378 million kilometers (or 231 to 235 million miles) from Earth, PUNCH captured images and even created an animation from daily frames. Since the spacecraft was fixated on the comet’s movement, background stars stretched into light trails, similar to what we’ve seen in other observations like those from Gemini South telescopes or the Hubble Space Telescope. And in a cool twist, a few frames show the bright streak of Mars whizzing by. The images also hint at the comet’s tail, a subtle extension pointing toward the lower right, like a comet’s characteristic plume of gas and dust. Given how dim the comet appeared, the PUNCH team was skeptical about clear visibility, but stacking those images again worked wonders, revealing the comet’s shape against the Sun’s blinding glow. As Kevin Walsh from the Southwest Research Institute in Boulder, Colorado, puts it, ‘We’re really pushing the limits of the system’ – a testament to human ingenuity in exploring the unknown.
Last but not least, the Solar and Heliospheric Observatory (SOHO), a collaboration between NASA and ESA, got its turn from October 15 to 26, 2025. Focused on solar observations, SOHO has a storied history of spotting comets – in fact, since launching in 1995, it’s discovered more than any other mission, with citizen scientists in NASA’s Sungrazer Project helping identify over half of all known comets from its images. Its Large Angle and Spectrometric Coronagraph (LASCO) instruments spied 3I/ATLAS from a whopping 358 million kilometers (222 million miles) away – farther than the average distance from Earth to the Sun. Once more, the comet was thought to be too faint, but clever processing and stacking brought it into sharp focus.
But here’s the part that might spark some debate: Is this comet really as ordinary as our own, or does its interstellar origin hint at something radically different about how comets form and behave across the galaxy? Some might argue that these observations confirm comets are universal building blocks, while others could wonder if 3I/ATLAS defies our models, suggesting alien worlds operate under unfamiliar rules. And this is where it gets controversial – should we invest more in tracking these rare visitors, even if they challenge our Earth-centric views of the universe?
The interstellar comet keeps surprising us with its secrets. If you’re curious to spot it yourself, check out our guide on observing comet 3I/ATLAS. What do you think – do these new insights from behind the Sun revolutionize our understanding of cosmic travelers, or are we just scratching the surface? Do you agree that prioritizing such missions is worth the effort, or should resources go elsewhere? Share your opinions in the comments below – we’d love to hear your take!