Asteroid Dinky's moon continues to shock scientists as latest images make startling revelation

NASA's Lucy mission has discovered a remarkable binary asteroid system in the first downlinked images. Initially, the two lobes of the contact binary appeared aligned during the closest approach, but additional images showed the system's true nature.

Earlier, the spacecraft beamed back images showing that Dinkinesh or Dinky had a satellite, its very own moon around it. Now some astounding information about this moon has come to light. This satellite orbiting Dinkinesh is not one but two conjoined space rocks, that is two smaller objects in contact with one another.

This means that the entire system comprises not one, or two rocks, but is actually made up of three space rocks. 

"It is puzzling, to say the least," Hal Levison, principal investigator for Lucy, said in a statement. "I would have never expected a system that looks like this. In particular, I don't understand why the two components of the satellite have similar sizes. This is going to be fun for the scientific community to figure out."

While contact binaries are not uncommon in the solar system, observing them up close is infrequent. What makes this discovery particularly unique is that one asteroid orbits another. Dinkinesh had shown peculiar brightness variations, hinting at the presence of a satellite.

“Contact binaries seem to be fairly common in the solar system,” said John Spencer, Lucy deputy project scientist, of the Boulder, Colorado, branch of the San-Antonio-based Southwest Research Institute.

“We haven’t seen many up-close, and we’ve never seen one orbiting another asteroid. We’d been puzzling over odd variations in Dinkinesh’s brightness that we saw on approach, which gave us a hint that Dinkinesh might have a moon of some sort, but we never suspected anything so bizarre!,” he added. 

Lucy's primary objective is to explore Jupiter's Trojan asteroids, with the encounter with a small, main belt asteroid like Dinkinesh added in early 2023.

This served as a test of the spacecraft's tracking and imaging system during high-speed flybys.

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Scientific community faces a puzzle

The binary asteroid system's characteristics have always confused scientists, especially the similarity in size between the two components of the satellite. 

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The Lucy mission is currently processing additional data from the encounter. Dinkinesh and its satellite are just the first of 11 asteroids that Lucy will explore during its 12-year journey.

(With inputs from agents)