Is the New “Nearly Interstellar” Object C/2025 V1 Related to 3I/ATLAS?
On November 2 2025, astronomer Gennady Borisov — who previously discovered the interstellar comet 2I/Borisov — announced the discovery of a new object labelled C/2025 V1 (Borisov) in the inner Solar System.
Its orbit is steeply inclined (113° to the ecliptic) and appears nearly perpendicular to the path of the interstellar object 3I/ATLAS.
The orbital eccentricity of C/2025 V1 is calculated at about 1.0095 with an uncertainty of ±0.0026.
On the face of it, that would classify the object as unbound (i.e., interstellar). Yet closer inspection suggests it most likely hails from the distant Oort Cloud at the outskirts of our Solar System.
Why it may not be truly interstellar
If you work the numbers back to ~1,000 AU from the Sun (where planetary perturbations are minimal), the eccentricity of C/2025 V1 tends to fall below unity. A modest gravitational nudge — maybe from Jupiter near perihelion — could tip a bound Oort-Cloud object into appearing momentarily hyperbolic (e > 1) under heliocentric fitting.
Further, non-modeled outgassing (i.e., cometary jets) can also skew the observed eccentricity upward, making a bound object mimic an interstellar one.
Is C/2025 V1 related to 3I/ATLAS?
Loeb examines whether C/2025 V1 shares a connection with 3I/ATLAS (which is itself enigmatic). He points out that the closest orbital separation between the two is about 0.5 AU (~75 million km), and they were never closer than ~1.5 AU (~225 million km) unless one of them employed non-gravitational propulsion.
The measured non-gravitational acceleration of 3I/ATLAS — though present — appears insufficient to bridge that gap. So far, there is no compelling evidence that C/2025 V1 is a fragment or probe associated with 3I/ATLAS.
The bigger picture: Natural vs. technological origin
One of the major questions around 3I/ATLAS is whether it is “natural” (i.e., a comet or asteroid) or “technological” (i.e., an artificial probe or spacecraft). Loeb notes that the latest imaging of 3I/ATLAS reveals a complex structure with at least seven jets pointing in various directions.
In a natural-comet scenario, the non-gravitational acceleration would require a large fraction of the body’s mass to have been expelled (in order to create sufficient reaction thrust). By contrast, a technological thruster could deliver comparable momentum with much less mass by ejecting gas at high speeds (chemical rockets: 3–5 km/s; ion thrusters: 10–50 km/s).
Hence, observing jet outflow velocities, mass fluxes and composition (e.g., via spectroscopy) during 3I/ATLAS’s upcoming closest approach (December 19 2025) will be a key test of its nature.
Why C/2025 V1 still matters
Even if C/2025 V1 proves to be a bound Oort-Cloud object rather than a true interstellar visitor, its discovery is still scientifically valuable. Objects on highly inclined orbits with eccentricity near unity challenge our understanding of Solar System dynamics, Oort Cloud reservoirs, and the boundary between bound and unbound objects.
Observing its physical and orbital properties (tail presence or absence, jetting behaviour, spectroscopy) will help refine models of how solar perturbations and outgassing affect orbital fits for distant comets.
Final thoughts
At this stage, Loeb’s assessment suggests that C/2025 V1 is unlikely to be genetically connected with 3I/ATLAS. Instead, it most likely represents a near-interstellar object from the Oort Cloud thrown into a high-inclination orbit by planetary/gravitational interactions and/or non-gravitational forces.
Further observations (particularly of jet activity and outgassing) will determine whether C/2025 V1 exhibits the kind of unexpected behaviour that would prompt re-evaluation of its origin.
If you’re following this story, the December 19 2025 perigee of 3I/ATLAS and forthcoming spectroscopy of C/2025 V1 will be moments worth watching
