Daily Telescope: Lucy finds not one but two diamonds in the sky
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Hopefully NASA got some good off-axis shots of the pair as Lucy approached and departed to determine the spacing. It's hard to tell from the image above if they're right on top of each other or well spread.
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Oh man, NASA needs to start doing live YouTube reveals when first data comes in.
It's like Space Maury Povich or something.
"NASA: Your careful examination said Dinkinesh was a small asteroid. The Lucy results are in and I have them right here in my hand. In the case of Dinkinesh... there are TWO ASTEROIDS!!!!!!!!"
Crowd goes wild with insane reveal disbelief.
"Come join us for next weeks episode when we finally reveal... what's inside the Bennu Mystery Box!!"
It's like Space Maury Povich or something.
"NASA: Your careful examination said Dinkinesh was a small asteroid. The Lucy results are in and I have them right here in my hand. In the case of Dinkinesh... there are TWO ASTEROIDS!!!!!!!!"
Crowd goes wild with insane reveal disbelief.
"Come join us for next weeks episode when we finally reveal... what's inside the Bennu Mystery Box!!"
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Is it me or does it look tidally locked?
(I'm not sure why the gif from NASA had a transparent frame around it)
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ColdWetDog
Ars Legatus Legionis
What's with the bulge around the midpoint of both of these rocks and Bennu? Seems to be a common thread amongst the few small asteroids we've recently seen.
Last year's thanksgiving dinner? That's my excuse anyway.
(image of Bennu showing similar morphology)
Last year's thanksgiving dinner? That's my excuse anyway.
(image of Bennu showing similar morphology)
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I would assume it's tidally locked. I hope they got enough data to estimate the orbital period. That would let them calculate the mass of the larger part.
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I doubt you're seeing any of the orbit. Lucy was whizzing past. So its view changed as it went, but the two bodies were essentially in the same orientation as when they started. Without doing some back-of-the-envelope math, I would expect the period to be many hours.
I mean, they could be tidally locked. But I don't think we have any evidence one way or another.
Edit: As per the NASA page for this, the images in the moving GIF span a 70-second interval. So yeah, the rocks were essentially stationary over that time span.
Edit 2: The closest approach is given as 430 km with a relative velocity of 4.5 km/s which leads to a maximum slew rate of just over half a degree per second.
Edit 3: I did the math below. Ballpark orbital period is 30+ hours.
Edit 4: Dtiffster pointed out that variations in brightness from both Lucy's approach and ground-based measurements suggest the orbital period is 52.7 hours.
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Given the name of the instrument (L-LORRI), is it fair to assume that this is a descendant of the LORRI that New Horizons used? If so, very neat to see and I'm assuming the basic architecture could be used for a large number of future probes.
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The NASA page doesn't mention anything about L'RALPH- did they have enough time to get some spectra from this encounter or was it just too fast?
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I recall reading about some modeling suggesting that an equatorial bulge might be the outcome of asteroid collisions. Take a rubble pile, smash it apart, and whatever debris remains gravitationally bound will coalesce into a disc. Eventually some of it settles onto the equator of the large main body, and since gravity is so weak it piles up high enough to make a wide belt around the asteroid.
https://news.arizona.edu/story/asteroids-bennu-and-ryugu-may-have-formed-directly-collision-spacehttps://www.nature.com/articles/s41467-020-16433-z
At some sufficiently large size, there would be enough gravity to pull things into a much more regular sphere shape. That's more formally called hydrostatic equilibrium, and is one of the defining features of the "dwarf planets" like Ceres.
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Mainline it into my veins, NASA! Space junkies everywhere rely on you for our fixes. It's astonishing stuff like this that keeps your funding flowing.
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L-LORRI is a descendent of the LORRI that New Horizons used. The first L is for Lucy.
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I assume the photo is grayscale (because color requires filters that reduce image quality), but if we looked at it with our own eyes would it look so gray?
I expect yes, since billions of years of UV exposure would break any of the double or triple-bonds that might give surface chemicals some color.
Still, do they have any multi-spectral info to confirm its general grayness?
Edit: the answer is yes, it does have a color camera. I couldn't find any images from it yet, though.
I expect yes, since billions of years of UV exposure would break any of the double or triple-bonds that might give surface chemicals some color.
Still, do they have any multi-spectral info to confirm its general grayness?
Edit: the answer is yes, it does have a color camera. I couldn't find any images from it yet, though.
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Puts into perspective the blurry mess if I try to photograph out of moving car window with a 70mm phone cam
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I am a surgeon, not a physicist so apologies if this question is ridiculous but is it abnormal for something as small as a half mile wide asteroid to have enough mass / gravity to retain a satellite? Does this allow any assumptions to be made of what the asteroid is composed of? As in, if it’s that size and has a satellite the material has to have a certain density or higher?
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It's a weeee babeh asteroid! Awesome to see that Lucy is working so well, and it's even better to get such an interesting target already.
As for my promise to work on astrophotography, I managed to collect some data last night! Might not have a fancy cam, and I'm in bortle 8, but I got some nice images of Jupiter with my phone and an eyepiece. Gonna spend today making it look tidy.
As for my promise to work on astrophotography, I managed to collect some data last night! Might not have a fancy cam, and I'm in bortle 8, but I got some nice images of Jupiter with my phone and an eyepiece. Gonna spend today making it look tidy.
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Like others here, I’m also amazed a body 800m wide has enough gravity to have a satellite 200m wide. From the gif it looks like about 800m gap between them, hence 1.3km centre to centre.
If we model them as spherical rocky masses it should be quite simple to find the orbit times, the distances etc. My lunch hour ended 10 mins ago so I don’t have time to go through the calculations right now.
If we model them as spherical rocky masses it should be quite simple to find the orbit times, the distances etc. My lunch hour ended 10 mins ago so I don’t have time to go through the calculations right now.
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I agree with the many, many posters that NASA and the space industry in general need to make lots more noise and climb into the 2020s as far as media and social reach.
They could easy hire a PR, even a small events/cinematography group and made a short but exiting event out of this. They can work with the various social and tv media outlets to promote such things.
As for viewership, I' sure they'll get more than they're getting now - I'm a space lover and only got to see these images here first on ARS (and I knew of this mission and visit NASA site often).
If there were a public and announce media event with even slight hype, I would've watched and I promise so would have many others that normally wouldn't really seek out space news.
I'm sorry I rant and I suppose I'm preaching to the choir here, but NASA and the US gov need to do 100x more to garner public interest in space (and STEM generally).
IMO the public is thirsty for news and a focus into other things we do as a society, especially positive things.
They could easy hire a PR, even a small events/cinematography group and made a short but exiting event out of this. They can work with the various social and tv media outlets to promote such things.
As for viewership, I' sure they'll get more than they're getting now - I'm a space lover and only got to see these images here first on ARS (and I knew of this mission and visit NASA site often).
If there were a public and announce media event with even slight hype, I would've watched and I promise so would have many others that normally wouldn't really seek out space news.
I'm sorry I rant and I suppose I'm preaching to the choir here, but NASA and the US gov need to do 100x more to garner public interest in space (and STEM generally).
IMO the public is thirsty for news and a focus into other things we do as a society, especially positive things.
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I think the answer here is...we don't know. This is the smallest we've directly imaged, so our data set is small. That question could lead to a future mission to try to find out, though I imagine that it would be tricky to plan enough encounters to answer it.
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Ballpark, the satellite is 3-5% of the mass of the primary. That's more than the moon, but not by a ton. And the only requirement that two objects remain bound is that their mutual attraction is more than perturbations from things like Jupiter. One did not necessarily capture the other. They may have been created at the same time either through a fracture of a larger parent and they've been traveling together ever since, or they both coalesced from the same ruble patch.
And fine: spheres of 200m and 800m with a specific gravity of 3. That's 12e9 kg and 7.7e11 kg. At 1.3 km (assuming a circular orbit) you get a period of 34 hours. Or, as I guessed before, many hours.
If we're not seeing a good angle perpendicular to the two bodies, the distance could be longer. That would make the period longer.
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I am also not a physicist, but it isn't only gravitational force at work, but also material sciences and chance.
I doubt it statically just sat there and simply gravitational pulled the smaller body closer - the smaller body could've simply drifted into it by ballistic coincidence, it could've been pushed towards it by having collided with another body, it could even formed by remnants of the larger body after having been stuck.
Also, the large percentage of ice in these bodies means that if they slowly drift into one another, that bump is enough to temporary melt some of the ice which will instant freeze again and have a chance of locking the bodies together like crazy glue. That if these 2 bodies are indeed in contact, as others have pointed out, the pictures alone do not clearly show that (however, to my eye, it looks like they are.)
All speculation of course, but space is a combination of a million random events every hour - I always tend away some single-cause/single-explanation when talking space phenomenon.
Edit: horrible spelling
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I actually came back into this article to say the same thing (except the surgeon part). It's weird* to me that an Earthican foothill can trap a satellite in orbit.
* Weird like unintuitive, not like I don't trust physics and this is all Big Asteroid's doing
Edit: I appreciate the explanations before and since, but @Wickwick lays it out in a way that makes sense to me. It's less of a "why?" than a "why not?"
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I think the more likely scenario is the one mentioned above - that the two objects originated from a single larger object.
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In space, well away from anything, what action is there to pull two bodies apart? Using my ballpark numbers above, the gravitational force between these two is 40
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Or a collision like formed the moon happened to the larger body. Some of the ruble escaped. Some coalesced back on the parent, and some formed the new satellite.
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From what I read last night about this, they actually saw variations in the apparent brightness from Lucy's instruments leading up to the flyby. The suspected this meant that it was a binary, but were waiting for the flyby to confirm. Earlier telescope observations had seen variations in spectra (which they blamed on variation in surface composition as it rotated) and estimated the rate of rotation as 52.7 hours. The periodicity of the brightness variations Lucy observed were supposedly inline with this time scale.
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The reason you think that is all the propaganda by Big Planet that doesn’t want you to believe the little ones are worthy of respect all on their own.
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That would be for spheres of diameter ratios of 4. But since the number given were for the largest dimension, I was being conservative. But it's in the ballpark of the moon's ratio to earth's mass either way.
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For a hack estimate, I'll take my 34+ hour approximation as pretty close to the correct answer of 52.7 hours.
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