The universe has a way of reminding us just how small and lucky we are. Every once in a while, it sends a stunning message across the dark sky — and this time, it’s doing so in triplicate. Astronomers have confirmed that three glowing green comets are currently visible from different parts of the world, marking one of the rarest celestial alignments in recent years.
These icy travelers — Comet Lemmon (C/2025 A6), Comet SWAN (C/2025 R2), and Comet ATLAS (C/2025 K1) — are putting on a breathtaking show for stargazers and sky photographers. While each has its own unique story, all three share the same mesmerizing emerald glow that makes them look almost unreal as they streak across the heavens.
—
Why are they glowing green?
That soft green light isn’t a camera trick — it’s pure chemistry at work. Comets are made mostly of rock, dust, and frozen gases. As they travel closer to the Sun, the heat causes these icy materials to vaporize, releasing a mix of gas and dust that forms a bright halo around them, called a coma.
The green color comes from molecules like diatomic carbon (C₂) and cyanogen (CN). When sunlight hits these gases, they fluoresce — literally glowing green. It’s the same reason many famous comets in history, like Comet Lovejoy and Comet NEOWISE, also appeared green to observers on Earth.
—
Meet the three glowing visitors
Comet Lemmon (C/2025 A6)
Discovered in early January 2025 by astronomers at the Mount Lemmon Observatory in Arizona, Comet Lemmon was initially faint and unremarkable. But as months passed and it traveled closer to the Sun, it brightened dramatically. In October, it became clearly visible through binoculars and small telescopes from many countries, glowing softly in the predawn sky.
Astronomers predict that Lemmon may remain visible through late October, especially before sunrise. Its long, elegant tail can already be captured in time-lapse photography under dark skies away from city lights.
Comet SWAN (C/2025 R2)
Comet SWAN was spotted in September 2025 through NASA’s SOHO spacecraft, which uses its SWAN instrument to track solar wind and comets. This particular comet is traveling from a distance of about 24 million miles and has been slowly growing brighter as it approaches the inner solar system.
For those in the Northern Hemisphere, SWAN can be seen after sunset in the western sky. Astronomers say its best viewing window falls around October 21, just after dusk — a perfect opportunity for amateur photographers to catch the green visitor in motion.
Comet ATLAS (C/2025 K1)
Discovered in May 2025, Comet ATLAS is the faintest of the trio, but no less fascinating. It’s expected to pass near the Sun in the coming weeks, though experts warn that it might break apart during its journey due to solar heat. If it survives, it will likely be visible with a telescope near dawn or dusk.
Even though ATLAS might not become as bright as Lemmon or SWAN, it adds a third act to this rare celestial performance — a cosmic reminder that the universe loves surprises.
—
When and where to look
Depending on your location, one or more of these comets can be seen during October.
Comet Lemmon: Best viewed before sunrise, low in the eastern sky.
Comet SWAN: Best viewed after sunset, in the western sky.
Comet ATLAS: Faint, but possibly visible near the horizon with a telescope.
If you live away from city lights or can find a dark sky area, you’ll have the best chance of seeing at least one of the three. A simple pair of binoculars or even a smartphone with a night-mode camera can help bring their glow into focus.
—
A cosmic reminder
It’s not often that three comets share the same sky. For astronomers, it’s a chance to study how these icy remnants from the early solar system behave as they near the Sun. For the rest of us, it’s a moment of wonder — a reminder that the universe is alive with motion, color, and mystery.
So wherever you are, take a moment this month to look up. You might just catch a glimpse of one of the green travelers passing by — a brief hello from the far edges of our solar system before they disappear again into the cosmic dark.