Interstellar Comet 3I/ATLAS Reappears After Swing Around the Sun

The interstellar comet 3I/ATLAS — only the third known visitor from beyond our solar system — has become visible again from Earth after passing behind the sun, new images show.

Astrophysicist Qicheng Zhang, a postdoctoral fellow at Caltech, confirmed the sighting on Sunday (Nov. 2) via his Cometary blog, noting that the object can now be seen with small telescopes across much of the Northern Hemisphere.

“All you need is a clear sky and a very low eastern horizon,” Zhang told Live Science. “It won’t look very impressive — just a smudge — but it will become increasingly visible over the next few days.”

Since its discovery in July 2025, comet 3I/ATLAS has intrigued astronomers with its unusually flat, straight trajectory through the solar system, traveling at over 130,000 mph (210,000 km/h). It reached its closest point to the sun, or perihelion, on Oct. 29, coming within 1.4 astronomical units (130 million miles / 210 million km).

Before and during perihelion, Zhang’s research indicated that the comet underwent rapid brightening and appeared distinctly blue, likely due to gas emissions. He suggests it may still be brightening, though more data is needed.

Using the Lowell Discovery Telescope, one of the few large observatories capable of tracking objects close to the horizon, Zhang captured the post-perihelion image when the comet was just 5 degrees above the horizon and 16 degrees from the sun.

The comet is now moving northward from Earth’s perspective and can be glimpsed in morning twilight, just above the northeastern horizon.

Captured earlier by the Gemini South Telescope in Chile, 3I/ATLAS has offered astronomers another rare glimpse into interstellar material passing through our solar system — following in the footsteps of ‘Oumuamua and 2I/Borisov.