When astronomers spotted 3I/ATLAS this past July, they knew they had something rare on their hands. An interstellar visitor—only the third ever confirmed—was blazing through our solar system at an astonishing 137,000 mph. But what happened earlier this week made the story even more compelling: the Sun itself hurled a coronal mass ejection directly at the passing object.
That sudden blast of plasma and magnetic fields is the kind of cosmic drama scientists usually watch play out against local comets. In fact, back in 2007, NASA’s STEREO A spacecraft observed Comet Encke lose its tail temporarily when a solar eruption swept across it. The tail reformed within minutes, but it proved that even relatively small brushes with solar fury can reshape a comet’s behavior. What’s unclear now is how 3I/ATLAS—larger, faster, and from beyond the solar system—handled the impact.
Size alone sets this visitor apart. Astrophysicist Avi Loeb has argued that 3I/ATLAS must weigh more than 33 billion tons and stretch at least 3.1 miles across. By comparison, ‘Oumuamua measured about a quarter mile in length, and 2I/Borisov came in around 0.6 miles. That makes this newcomer far more massive than anything interstellar researchers have studied before.
It’s also behaving strangely. Spectral analysis revealed a higher-than-expected ratio of carbon dioxide to water, and as it closed in on the Sun earlier this month, it flared with green light. That glow wasn’t just for show—it’s the telltale emerald signal of diatomic carbon molecules reacting to intense solar UV radiation.
Trajectory adds another layer of mystery. The object’s path seems almost too neat, sweeping it close to Jupiter, Mars, and Venus. Next week, it’s set to pass within just 1.67 million miles of Mars—what Loeb called a “remarkable fine-tuning of its path.” Whether that alignment is coincidence or something more remains hotly debated.
For now, the unanswered question is how it fared against the solar storm. Did it lose material? Did its tail reform instantly, like Encke’s? Or did its unusual mass and chemistry shield it from the kind of disruption solar comets typically endure? As Futurism reports, astronomers are watching closely. With Mars flyby observations looming, 3I/ATLAS may soon give up a few more of its secrets.
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