October 2025 is shaping up to be one interesting month for sky watchers. Besides the awesome Orionids Meteor Shower (peaking on the 21st), we also have two spectacular, potentially naked-eye, comets approaching their peak brightness, AND we’re hosting a guest from beyond our own solar system!

We will dive into the Orionids soon but for now- Here’s your guide on how to spot Comet Lemmon, Comet SWAN, and the mysterious interstellar object 3I/ATLAS this month.

It's true: a complete stranger from beyond our solar system is visiting our neck of the galaxy- and it’s passing through our planetary neighborhood right now. First spotted in July 2025 by the ATLAS (Asteroid Terrestrial-impact Last Alert System) telescope in Chile, this mysterious visitor has had everyone talking. Here's what you should know…

It’s all in the name—“interstellar” means this object hails from beyond the gravitational reach of our Sun. Our solar system is, at its core, one star and a host of companions—planets, asteroids, and comets—locked into its pull, orbiting in a cosmic dance.

But this object is different. Unlike our bound celestial bodies, this one has a hyperbolic trajectory: a sling-shot arc that whips it around the Sun and flings it back into the deep unknown, never to return. So while the residents are all circling the sun, this is clearly a visitor because it is not. It is moving very fast and heading in a completely different direction than everything else. It's an untethered wanderer just passing through.

This is not the first confirmed interstellar object we have ever hosted, either. In fact, it’s the third- following the first, I/ʻOumuamua (2017) and the second, I/Borisov (2019). The name 3I/ATLAS simply means it's the 3rd Interstellar object discovered by the ATLAS program.

When astronomers first spotted 3I/ATLAS some red flags were raised and plenty of people were wondering if this could be some kind of alien messenger. Its extreme speed was one red flag- it’s traveling at 58 km/s (over 210,000 km/h) relative to the Sun. The highly unusual path was red flag number 2 and that sparked intense speculation. Harvard astrophysicist Dr. Avi Loeb, who also weighed in on ʻOumuamua, even suggested it could be a technological object, like an alien light sail.

However, the scientific consensus is in:

Comet 3I/ATLAS is currently very close to the Sun in our sky, approaching solar conjunction. As of the time of this writing (October 15, 2025), it is unobservable from Earth for a few weeks because the Sun's glare is completely washing it out.

Its closest approach to the Sun (perihelion) will occur on October 29, 2025, just before it reappears on the other side of the solar system from our perspective. The only way to "watch it travel live" from Earth right now is to consult interactive trackers, such as NASA's Eyes on the Solar System, which show its theoretical path.

The comet's current unobservable status is a perfect astronomical demonstration of the astrological concepts of combustion and cazimi—a time when a body's visibility is entirely dependent on its angular separation from the Sun.

When a celestial body (like 3I/ATLAS or a planet) is within a certain angular distance of the Sun, it is considered combust.

As the body passes directly in front of or behind the Sun, reaching an extremely tight angular separation, it goes from combust to cazimi (from the Arabic kaṣīmī, meaning 'as if in the heart').

Astronomically, 3I/ATLAS is passing through the region of combustion on its way to perihelion and conjunction, becoming invisible to terrestrial observation before it reappears on the other side.

While the comet is too distant and faint to be seen with the unaided eye even at its brightest, observers with an 8-inch to 10-inch aperture telescope should prepare for its reappearance.

The comet will clear the Sun and reappear in the predawn sky after its perihelion passage. It is expected to be at its most accessible brightness for Earth observers between October 30 and November 7, 2025, favoring a view in the early morning hours.

While 3I/ATLAS is scientifically fascinating, it is a faint object that is currently only visible with powerful telescopes. The real treat for casual skywatchers this month is the rare simultaneous appearance of two much brighter, long-period comets from our own solar system's distant Oort Cloud.

The current appearances of Comets C/2025 A6 (Lemmon) and C/2025 R2 (SWAN) are rare, as both are classified as non-periodic or long-period comets. This means they have extremely long orbits (measured in millennia) making their visit a once-in-a-lifetime sight.

Comets are generally categorized by their orbital period—the time it takes for them to complete one trip around the Sun.

For long-period comets like Lemmon and SWAN, planetary gravity can alter their path, meaning they may never return to the inner solar system, or if they do, it's a visit separated by vast stretches of time.

How long, you ask?! I was wondering the same thing, so I did some research. And then some more. This is what I found out…

The approximately 1,150 year orbit of Comet Lemmon (C/2025 A6) means it last swept past Earth around the year 629 AD. To put this in perspective, this was a time when the world was on the cusp of truly monumental changes…

While the comet flew overhead, the Prophet Muhammad (who passed away three years later) was solidifying the foundation of the new religion of Islam, which would soon expand across the entire Middle East and North Africa. Meanwhile, in China, the Tang Dynasty—often called the Golden Age of Chinese Art and Culture—was only about a decade into its 300-year reign, becoming one of the most powerful and influential empires in world history. Observing Lemmon’s return today is to witness a spectacle that last graced the sky at the very dawn of the modern world.

In the regions that would one day become the United States and Canada, the year 629 AD was defined by established indigenous cultures that were centuries away from European contact. Across the vast North American landmass, the Late Eastern Woodland cultures were thriving east of the Mississippi River, engaged in agriculture, and setting the cultural stage for the later mound-building Mississippian societies. Meanwhile, in the Southwest, the Ancestral Puebloans were actively developing their farming techniques and constructing early communal settlements, transitioning from nomadic to more fixed, agricultural lifeways in the arid environment.

Comet Lemmon’s reappearance offers a rare moment to reflect on time’s vastness. It’s a cosmic breadcrumb—an icy archive of ancient dust—looping back around to us after more than a millennium. What stories did it witness last time? What dreams will it spark now?

Today, we are the modern equivalent of the 629 AD sky-watchers—be they the Classic Maya establishing new cities, the first generations of the Tang Dynasty, or the early adherents of Islam. They were on the cusp of world-defining change; we, too, stand at a major inflection point in human history. This celestial visitor prompts the profound contemplation: if the world advanced this far by its return, what will the human journey look like when Comet Lemmon completes its next long, silent orbit? These are the hidden questions and immense spans of wonder unmasked by the cosmos, far beyond the spectacle of a green object simply flying overhead.

As you gaze up this October and November, remember: you’re watching a traveler that once lit the skies for Tang poets, Maya astronomers, and Anglo-Saxon monks. Let it be a portal—not just to the stars, but to the mythic threads that bind us across centuries.