When NASA’s Lucy mission flew previous asteroid Dinkinesh on November 1, 2023, it made the stunning discovery the asteroid had a tiny moon. Then got here one other shock. This wasn’t simply any moon, however a contact binary moon, the place two house rocks are gently resting towards one another. After all, this new and distinctive moon wanted a reputation, so the Worldwide Astronomical Union (IAU) has simply authorized authorized “Selam,” which suggests peace in Ethiopia’s language.
However, all the pieces’s linked right here. Dinkinesh is the Ethiopian title for the Lucy fossil, and Selam is called after one other fossil from the identical species of human ancestor.
The Lucy mission is called after the hominid skeleton fossil known as Lucy that was found in Ethiopia in 1974. Lucy (in flip, named after the Beatles tune, “Lucy within the Sky With Diamonds) is estimated to be 3.18 million years previous. This fossilized human ancestor has supplied distinctive perception into humanity’s evolution. Likewise, the Lucy mission will revolutionize our data of planetary origins and the formation of the Photo voltaic System.
The fossil Selam was found in 2000 in Dikika, Ethiopia, and belonged to a 3-year-old woman of the identical species as Lucy. Although this fossil is known as Lucy’s child, the “child” truly lived greater than 100,000 years earlier than Lucy.
“It appeared applicable to call its satellite tv for pc in honor of one other fossil that’s generally known as Lucy’s child,” mentioned Raphael Marshall of the Observatoire de la Côte d’Azur in Good, France, who initially recognized Dinkinesh as a possible goal of the Lucy mission.
The flyby of Dinkinesh served as a check for Lucy’s devices on its strategy to the Trojan asteroids, a big group of asteroids that share the identical orbit as Jupiter.
This primary asteroid encounter for the Lucy mission actually shocked everybody. Not solely was there the shock of the beforehand hidden contact binary, however the surprisingly high-resolution photos revealed boulder-strewn floor on each small worlds. Up shut, 790 meter-wide Dinkinesh appears quite a bit like 101955 Bennu, visited by OSIRIS-REx. NASA says that we are able to anticipate to see extra photos of the flyby with extra processing quickly, saying that the group has accomplished downlinking the info from Lucy’s first asteroid encounter and is continuous to course of it.
The Dinkinesh encounter was added in January of this yr as an in-flight check of the spacecraft’s programs and devices, and in a current Lucy weblog submit by Katherine Kretke of the Southwest Analysis Institute, she says all programs carried out effectively.
“The instruments and methods refined with information from this encounter will assist the group put together for the mission’s principal targets, the never-before-explored Jupiter Trojan asteroids,” Kretke wrote. “Along with the photographs taken by Lucy’s high-resolution L’LORRI digicam and its Terminal Monitoring Cameras (T2Cam), Lucy’s different science devices additionally collected information that may assist scientists perceive these puzzling asteroids.”
The mission plan for Lucy is at present to go to 9 extra asteroids over the subsequent decade in 6 separate encounters. After an Earth gravity help in December 2024, the spacecraft will return to the primary asteroid belt the place it’s going to encounter asteroid Donaldjohanson in April 2025. Lucy will go by way of the primary belt and attain the mission’s main targets, the Jupiter Trojan asteroids, in 2027.
