In a fascinating twist, NASA’s asteroid probe Lucy has made a groundbreaking discovery during its first flyby of the asteroid Dinkinesh. It turns out that Dinkinesh is not alone in the vast expanse of space. This gray space rock has a tiny moonlet, orbiting in close proximity. This unexpected finding suggests the existence of numerous binary asteroids in the Solar System, providing valuable insights into the growth and interaction of rocks in space.
Contrary to the belief that we have already explored asteroids extensively, this discovery challenges our assumptions. Planetary scientist Simone Marchi of the Southwest Research Institute points out, “Well, that is clearly wrong. Dinkinesh, and its enigmatic moonlet, differ in some interesting ways from the similarly sized near-Earth asteroids that have been seen by spacecraft like OSIRIS-REx and DART.”
A Mystery in the Solar System
While we are aware of the existence of binary, trinary, and even quaternary asteroids in the Solar System, the frequency of the formation of such closely orbiting groups remains uncertain. Although asteroids tend to travel in groups, like the main belt and Trojan asteroid swarms around Jupiter, it is unclear how often they come close enough to become gravitationally bound. Nonetheless, as Lucy approached Dinkinesh in the weeks leading up to the flyby, its changing brightness hinted at the presence of a second object. This fluctuation in brightness often occurs when a binary system orbits, causing variation in the light reflected by the asteroid. The suspicions of a moonlet orbiting Dinkinesh were confirmed when Lucy obtained detailed images during the flyby.
The Dance of Dinkinesh and Its Moonlet
Observations made during the flyby revealed two objects engaged in a delicate orbital dance. Preliminary measurements indicate that the larger of the two rocks is approximately 790 meters in width, while the smaller one measures a relatively modest 220 meters. Planetary astronomer Keith Noll of NASA’s Goddard Space Flight Center expresses excitement over this discovery, stating, “The fact that it is two makes it even more exciting… there are some really interesting differences that we will be investigating.”
Asteroids, particularly those inhabiting Jovian orbits, are believed to contain materials from the early stages of the Solar System. These asteroids provide a glimpse into the pristine conditions that existed during the formation of planets. Lucy’s mission aims to study these asteroids to gain a deeper understanding of the Solar System’s origins and the processes that led to the emergence of our planets. By uncovering more binary asteroids like Dinkinesh, researchers can shed light on the accumulation and merging of smaller rocks, which likely contributed to the formation of rocky worlds in the inner Solar System.
While the flyby provided crucial insights into Dinkinesh and its moonlet, there is much more to learn. Extracting and analyzing the remaining data from the Lucy mission will not only enhance our knowledge of this specific asteroid but also provide valuable insights into the functioning of the spacecraft itself. As we eagerly await the full extraction of Dinkinesh’s data, Lucy continues its journey toward its next destination: the asteroid Donaldjohanson. The rendezvous with Donaldjohanson is scheduled for 2025, adding another exciting chapter to our exploration of the Solar System.
The discovery of a binary asteroid, Dinkinesh, and its moonlet has opened up new possibilities for our understanding of the Solar System’s composition and formation. This unexpected finding challenges our preconceived notions and demonstrates that there is still much to uncover and comprehend about the vast expanse of space. As Lucy embarks on its 12-year mission to explore various asteroids, it holds the potential to revolutionize our knowledge and reshape our understanding of the universe we inhabit.