A Star's Flyby 2.5 Million Years Ago May Have Triggered a Comet Cascade

Where Do Comets Come From? Scientists Offer a Fresh Theory

According to Radiotrek — Світ: A study released on June 30, 2026, links today's comet frequency to a close encounter between our solar system and the star HD 7977 roughly 2.5 million years ago. The star's gravitational pull likely dislodged objects from the Oort Cloud, sending them hurtling into the inner solar system and generating a new wave of long-period comets. This research sheds light on how cosmic events millions of years in the past can still influence the celestial phenomena we observe today.

Located at the solar system's edge, the Oort Cloud is a vast reservoir of icy bodies. Under normal circumstances, the Milky Way's gravity shapes comet orbits. However, scientists argue that the near passage of HD 7977 could have dramatically altered the trajectories of countless icy objects in this distant region.

'This star passed relatively close to the Sun-close enough to shift the orbits of many icy objects.' Universe Space Tech

An analysis of comet orbits suggests they align with the scenario of a stellar flyby. Still, the model is not flawless; certain orbital parameters do not perfectly match the calculations. It is likely that this event sparked a distinct influx of new long-period comets, a pattern corroborated by astronomical observations.

The article was authored by Olena Shvydka, and the findings were featured in Universe Space Tech.

This study marks a significant step in understanding the solar system's dynamics and its evolution over millions of years. Pinpointing how stellar flybys shape comet formation helps scientists better grasp how external forces can alter the orbits of objects within our system, which in turn has implications for planning space missions and observations. Further research in this area could lead to new breakthroughs in astronomy and cosmology.

As we explore the intricate dynamics of our solar system, it's essential to consider other cosmic phenomena that impact galactic evolution. For instance, recent findings from the Webb Telescope highlight the destructive winds affecting galaxies, illustrating how various forces shape the universe in ways that echo the influences of stellar encounters like that of HD 7977. Understanding these connections can deepen our appreciation of cosmic interactions.