2025 proved to be an exceptional year for comet sightings, capturing attention from both scientists and the public. Three comets in particular—Lemmon, C/2025 R2 (SWAN), and 3I/Atlas—dominated celestial observations, each for distinct reasons. While one sparked unfounded speculation about extraterrestrial origins, all offered unique scientific opportunities.
The Comet Lineup: Lemmon, SWAN, and Atlas
Comet Lemmon, discovered in January, remained visible for nine months, its long tail a striking sight. In September, C/2025 R2 (SWAN) appeared, so bright it was still observable even near the moon on Halloween. Most notably, Comet 3I/Atlas gained fame not just for its interstellar origin—meaning it came from outside our solar system—but also for unsubstantiated claims that it was an alien probe.
The fact that 3I/Atlas is interstellar is significant. It provides a rare chance to study material from another star system. Even without pinpointing its exact origin, scientists can analyze its composition to infer characteristics of the distant star it came from.
Historical Perspective: Comets and Human Interpretation
Humanity has long projected meaning onto celestial events. The appearance of Halley’s Comet in 1066 was famously depicted as a harbinger of the Norman invasion of England. While we now understand that the universe doesn’t revolve around us, the instinct to seek patterns and signs in the cosmos persists.
A Year of Challenges and Hope
The comets arrived during a turbulent year marked by political instability, social division, and attacks on vulnerable communities. As the author, a Black, Jewish, queer scientist and child of immigrants, points out, these events create an environment where even scientists might be tempted to read ominous signs into the natural world. Yet, the comets also offer a different perspective: they represent beauty, wonder, and the unifying power of scientific curiosity.
The shared experience of comet-hunting has brought people together, as evidenced by the enthusiasm in astrophotography groups. Despite misinformation, the simple act of looking up at the sky remains a source of hope and connection.
Looking Forward: Science, Equity, and Big Dreams
The comets of 2025 remind us that the universe is full of surprises. Just as we seek out these celestial wonders, we must also work towards a better world—one where all children have access to essential resources and live in affirming communities. These goals may seem ambitious, but the universe itself demonstrates that extraordinary things are possible.
