Lucy’s first encounter with an asteroid produced surprises
At the 55th annual Lunar and Planetary Science Conference presently being held in Texas, the science team for the Lucy asteroid mission presented their first papers outlining what they learned during the spacecraft’s first asteroid encounter, flying past the main belt asteroid Dinkinesh on November 1, 2023.
To the right is the the best image taken at closest approach, at about 270 miles distance, annotated to include the analysis of Dinkinesh’s shape by scientists. As noted in the summary paper [pdf], the asteroid is about a half mile in diameter, and appears to have an equatorial ridge, similar to the ridges found on the near-Earth rubble-pile asteroids Bennu or Ryugu. Dinkinesh is not a rubble pile, however. Though boulder-strewn, it appears more solid, and even has what the scientists call a longitudinal trough, as indicated in the picture.
The ridge overlays the trough implying that it is the younger of the two structures. However, there is as yet no information to better constrain their relative ages, and thus they could potentially have formed in the same event. Indeed, Dinkinesh’s ridge and trough are likely the result of mass failure and the reaccretion of material, and may both be linked to the formation of Selam.
That flyby had produced one major surprise, the existence of a smaller satellite asteroid orbiting Dinkinesh, now dubbed Selam. It is shown in the lower left, as it appeared from behind the main asteroid as Lucy flew past. A later picture however revealed an even greater surprise.
The picture to the right is a close-up of Selam, taken about six minutes after closest approach from a distance of about 1,000 miles. To the shock of everyone, it turned out that Selam is a contact binary, apparently made of two objects fused together.
Selam consists of two near-equal sized lobes of ∼200 meters each [about 650 feet). It orbits Dinkinesh at a distance of roughly 3km [about 2 miles].
The solar system continues to prove a fundamental maxim: Once we get our first close look at any object, we always find that every single object is utterly unique, remarkably different from every other object.
Lucy is going to give us a lot more unique surprises, as its main mission to explore the Trojan asteroids that orbit the Sun in Jupiter’s orbit, sixty degrees fore and aft of the gas giant. It will do close-flys of nine Trojans from 2027 to 2029, after flying past another main belt asteroid in April 2025.
The support of my readers through the years has given me the freedom and ability to analyze objectively the ongoing renaissance in space, as well as the cultural changes -- for good or ill -- that are happening across America. Four years ago, just before the 2020 election I wrote that Joe Biden's mental health was suspect. Only in this year has the propaganda mainstream media decided to recognize that basic fact.
Fourteen years ago I wrote that SLS and Orion were a bad ideas, a waste of money, would be years behind schedule, and better replaced by commercial private enterprise. Even today NASA and Congress refuse to recognize this reality.
In 2020 when the world panicked over COVID I wrote that the panic was unnecessary, that the virus was apparently simply a variation of the flu, that masks were not simply pointless but if worn incorrectly were a health threat, that the lockdowns were a disaster and did nothing to stop the spread of COVID. Only in the past year have some of our so-called experts in the health field have begun to recognize these facts.
Your help allows me to do this kind of intelligent analysis. I take no advertising or sponsors, so my reporting isn't influenced by donations by established space or drug companies. Instead, I rely entirely on donations and subscriptions from my readers, which gives me the freedom to write what I think, unencumbered by outside influences.
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At the 55th annual Lunar and Planetary Science Conference presently being held in Texas, the science team for the Lucy asteroid mission presented their first papers outlining what they learned during the spacecraft’s first asteroid encounter, flying past the main belt asteroid Dinkinesh on November 1, 2023.
To the right is the the best image taken at closest approach, at about 270 miles distance, annotated to include the analysis of Dinkinesh’s shape by scientists. As noted in the summary paper [pdf], the asteroid is about a half mile in diameter, and appears to have an equatorial ridge, similar to the ridges found on the near-Earth rubble-pile asteroids Bennu or Ryugu. Dinkinesh is not a rubble pile, however. Though boulder-strewn, it appears more solid, and even has what the scientists call a longitudinal trough, as indicated in the picture.
The ridge overlays the trough implying that it is the younger of the two structures. However, there is as yet no information to better constrain their relative ages, and thus they could potentially have formed in the same event. Indeed, Dinkinesh’s ridge and trough are likely the result of mass failure and the reaccretion of material, and may both be linked to the formation of Selam.
That flyby had produced one major surprise, the existence of a smaller satellite asteroid orbiting Dinkinesh, now dubbed Selam. It is shown in the lower left, as it appeared from behind the main asteroid as Lucy flew past. A later picture however revealed an even greater surprise.
The picture to the right is a close-up of Selam, taken about six minutes after closest approach from a distance of about 1,000 miles. To the shock of everyone, it turned out that Selam is a contact binary, apparently made of two objects fused together.
Selam consists of two near-equal sized lobes of ∼200 meters each [about 650 feet). It orbits Dinkinesh at a distance of roughly 3km [about 2 miles].
The solar system continues to prove a fundamental maxim: Once we get our first close look at any object, we always find that every single object is utterly unique, remarkably different from every other object.
Lucy is going to give us a lot more unique surprises, as its main mission to explore the Trojan asteroids that orbit the Sun in Jupiter’s orbit, sixty degrees fore and aft of the gas giant. It will do close-flys of nine Trojans from 2027 to 2029, after flying past another main belt asteroid in April 2025.
The support of my readers through the years has given me the freedom and ability to analyze objectively the ongoing renaissance in space, as well as the cultural changes -- for good or ill -- that are happening across America. Four years ago, just before the 2020 election I wrote that Joe Biden's mental health was suspect. Only in this year has the propaganda mainstream media decided to recognize that basic fact.
Fourteen years ago I wrote that SLS and Orion were a bad ideas, a waste of money, would be years behind schedule, and better replaced by commercial private enterprise. Even today NASA and Congress refuse to recognize this reality.
In 2020 when the world panicked over COVID I wrote that the panic was unnecessary, that the virus was apparently simply a variation of the flu, that masks were not simply pointless but if worn incorrectly were a health threat, that the lockdowns were a disaster and did nothing to stop the spread of COVID. Only in the past year have some of our so-called experts in the health field have begun to recognize these facts.
Your help allows me to do this kind of intelligent analysis. I take no advertising or sponsors, so my reporting isn't influenced by donations by established space or drug companies. Instead, I rely entirely on donations and subscriptions from my readers, which gives me the freedom to write what I think, unencumbered by outside influences.
Please consider supporting my work here at Behind the Black.
You can support me either by giving a one-time contribution or a regular subscription. There are five ways of doing so:
1. Zelle: This is the only internet method that charges no fees. All you have to do is use the Zelle link at your internet bank and give my name and email address (zimmerman at nasw dot org). What you donate is what I get.
2. Patreon: Go to my website there and pick one of five monthly subscription amounts, or by making a one-time donation.
3. A Paypal Donation:
5. Donate by check, payable to Robert Zimmerman and mailed to
Behind The Black
c/o Robert Zimmerman
P.O.Box 1262
Cortaro, AZ 85652
You can also support me by buying one of my books, as noted in the boxes interspersed throughout the webpage or shown in the menu above. And if you buy the books through the ebookit links, I get a larger cut and I get it sooner.
Cue J.B.S. Haldane.
Truly amazing what exists “out there”! Let’s just hope it all STAYS “out there”!!
I really enjoy the variation of articles here – THANKS!!