Astronomers have made a significant discovery with the identification of a large asteroid, designated 2025 SC79, which has an exceptionally rapid orbit around the sun. This celestial body, first observed by Scott S. Sheppard from Carnegie Science on September 27, 2023, completes a full orbit every 128 days, making it the second-fastest known asteroid in our solar system.
The discovery of 2025 SC79 enhances our understanding of potential threats to Earth, as well as providing valuable insights into the history of the solar system. Notably, this asteroid is the second known object to have an orbit that lies within that of Venus, crossing the orbit of Mercury during its journey around the sun.
Understanding the Risks and Origins
Many asteroids in the solar system reside in two primary belts of space rocks. However, perturbations can cause some of these objects to enter closer orbits, making them more difficult to detect. Sheppard explained, “Understanding how they arrived at these locations can help us protect our planet and also help us learn more about solar system history.”
At present, 2025 SC79 is positioned behind the sun, rendering it invisible to telescopes for several months. This discovery is part of Sheppard’s ongoing research into “twilight” asteroids, which are those that could pose a risk of colliding with Earth. His work, partially funded by NASA, utilizes the Dark Energy Camera on the National Science Foundation’s Blanco 4-meter telescope to search for “planet killer” asteroids hidden in the sun’s glare.
In addition to the Blanco telescope, Sheppard confirmed the sighting of 2025 SC79 using the NSF’s Gemini telescope and the Magellan telescopes. Notably, the fastest known asteroid, also discovered by Sheppard and his colleagues in 2021, takes 133 days to complete its orbit around the sun.
This latest finding underscores the importance of continuous monitoring of near-Earth objects to ensure planetary safety. As astronomers continue to uncover more about these celestial bodies, our understanding of the cosmos—and our place within it—grows deeper.
