Post-perihelion changes, close flybys, and preparing for end of mission!
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Discussion: 14 comments
Hi Emily
(Second attempt- comment box swallowed it) Claire Vallat said Rosetta was going to do very close orbits. Even if you don’t perform Marco’s escape and return scenario, could you still do my suggested Apis flyby?
https://scute1133site.wordpress.com/2016/09/01/part-59-the-dare-devil-apis-flyby-escape-and-2020-reacqusiton/
We think Apis is the most primordial section of crust on the comet. That’s according to stretch theory, which isn’t mainstream. If it is eventually accepted that 67P stretched, we’d have the close-up Apis data under our belts- we can’t go back for it! I’m sure it would prove every bit as useful in the future as the crash trajectory data.
The Apis flyby is at 0.25 m/sec whereas the crash trajectory is at 0.5 m/sec. The Apis ground track would take a full 27 minutes to cross, allowing for large amounts of data to be taken and transmitted later. The crash at Ma’at will be sending smaller amounts of data in real time.
The flyby scenario in the link above exploits a crash avoidance technique that only Apis, stuck out on the long axis tip, can offer. That’s how Rosetta can scrape so low and still avoid crashing if a negative altitude anomaly occurs. If the negative anomaly is so low that she does crash then we won’t be any worse off than for the controlled crash scenario anyway, provided the Apis flyby is done just before the controlled crash.
It’s interesting that Capaccione reiterated that there were compounds mixed in the nucleus that require a very high temperature to form. Expected though, as this was also a finding of stardust.
Far from identifying where the nucleus was formed as in the Rosetta stone analysis deciphering ancient egyptian language, a multitude of contradictory findings have to believed together to explain everything.
It’s stuff formed in single digit Kelvin mixed with elements born in fire accreted together where somehow magically O2 got trapped in clathrates, then two km sized cometismals formed that way had a magic kiss in the night rendezvous and lived happily ever after until being bundled into the Jupiter zone, recently, but not so recently that the whole surface was processed but none of the interior. It’s not science. It’s a fairy tale intellectuals tell their children at night to make it sound like we know something when we don’t have a clue yet.
Yes we have more data – But it is a bad sign for “deciphering the history of comet nuclei” with such radically contradictory conclusions from the different aspects. Hot formation? cold formation? Collisionally relaxed? Formed through multiple collisions?
It would be better to say as Jean-Pierre Bibring reiterated after describing the pristine nature of comets forming
“But we are not too sure about this”
Rosetta: Oh no! The end is in sight!
Please don’t euthenase me. I’m old, but with a good sleep,, I can come back!
https://marcoparigi.blogspot.com.au/2016/06/rosetta-lament.html
Carsten Guttler mentions a really interesting boulder movement., however, something is not right with the maths. He mentions a moving boulder which sounded like the Anuket boulder movement, but then his size/mass values didn’t add up. He said ten tonnes (meaning I’m quite sure he means tonne to be the “international accepted SI unit of mass” ie the mass equivalent of 10,000 kg). His 100g chocolate bar translates to 10,000kg as well. So that seems correct. But he said a 50-metre boulder. One would assume 50 m is for the diameter so for a 25m radius boulder the mass is 4/3pir^3 x 530kg/m^3= 34,693 tons (mass equivalent ~34 million kg) I know these are all based on rough estimates, but his mass/size translations are orders of magnitude out.
I am thinking he had in mind 50 X 1m boulders which would be close, at about 13 tonnes.
I had roughly estimated for the Anuket movement, maybe 1000 tonnes mass for the 15m diameter moving object (10 kg weight on 67P’s gravity) moving about 60m down the neck relative to nearby features. My suggested mechanism of movement is something akin to a landslide triggered by subsurface movement perhaps associated with a “duck quake” due to a nearby outburst. However, my underlying hypothesis is the lobes are further apart after perihelion and both the surface and subsurface are moving horizontally to allow for it – a little bit similar to the way mid ocean ridges allow for continental drift.
This is the post which proves beyond reasonable doubt the Anuket movement.
https://marcoparigi.blogspot.com.au/2016/08/andrew-coopers-confirmation-of-boulder.html
@Marco,
“This is the post which proves beyond reasonable doubt the Anuket movement.”
Not to me it doesn’t.
Hi ianw16
Just like with Gerald and the ‘sliding pancake gifs’ your comment doesn’t have any potency if you don’t engage with the argument we’re presenting. The blog post which Marco linked and you’ve just dismissed is the one which you critiqued in a comment with a link to several annotated photos. I then replied to that comment by critiquing your critique. That was two weeks ago and you didn’t reply.
I don’t make a habit of badgering commenters who don’t or can’t reply but most of them retire graciously to fight another day on another theme. But if you come back to level the same criticism at the same blog post I have to draw your attention to the riposte I made, to which you haven’t replied.
https://blogs.esa.int/rosetta/2016/07/28/how-comets-are-born/#comment-603284
Your comment to which this is a reply is here, a few comments above it:
https://blogs.esa.int/rosetta/2016/07/28/how-comets-are-born/#comment-603145
Hi Ianw16,
Of course I respect your considered judgement. There is not much accounting for unreasonable doubt.
What do you think Carsten Guttler was referring to with his mathematically improbable Boulder movement?
@Marco,
It was an interview. He probably didn’t have a script. He was not using his first language. One of the parameters he used was probably misremembered, or he made a slip. Wait for the paper. That is what is called a ‘primary reference’. Interviews and press releases are not. It is a favourite trick of EU to reference such things as ‘evidence’ for their nonsense. Don’t go down the same path.
Hi Ianw16,
You are probably right. It was probably an optical illusiion like the Anuket Boulder 😉
Maths is a universal language, and I think it rather important, and one of the things that is rather lacking in all EU arguments, weakening them.
Either way it is not a good look for any scientist. Much better not to mention numbers at all if they are orders of magnitude out, or in this case, poorly checked.
Wow. If I heard correctly, one of the speakers said that the Imhotep plain has fallen by ~ 3m! Given that that is where we saw some interesting changes earlier in the mission, it would be interesting to know what’s going on there.
I’m guessing that the ice must be close to the surface there, as was seen in the southern hemisphere by MIRO. I saw a conference poster about MIRO having surveyed an 800m swath of Imhotep back in October 2014, but never saw a paper on it, from memory.
https://adsabs.harvard.edu/abs/2016EGUGA..1818371V
I also saw a poster from the cancelled COSPAR meeting, about a large area in Khepry losing ~ 12m of material laterally:
https://adsabs.harvard.edu/abs/2016cosp…41E1109L
Usual proviso with adsabs links; you’ll have to highlight the whole link and copy/ paste it into a browser.
Hi Ianw16
It was in Groussin et al. (2015) and they said 5 metres plus/minus 2 metres. It was 40% of the Imhotep smooth terrain at the time of observation just prior to perihelion and appears to have spread a little further since. So it’s in the low millions of cubic metres. They said very little accompanying dust in the form of jets, implying no commensurately major outgassing. The rate of ‘erosion’ implied sublimation that was two or more orders of magnitude more than models predicted (that’s from memory, fairly sure though). It points to subsidence rather than erosion in my opinion.
This is what I think your 50-metre cliff erosion on Tempel 1 was doing. It’s a similar smooth terrain and I think it may have subsided back by 50 metres rather than eroded. It’s much harder to tell because the photos are so much more grainy.
Groussin et al. identified five areas that grew and merged. I found the focus (instigation point) for area B, put it in a page on my blog and linked it on the “Changing Comet- Call for Contributions” Rosetta blog post. I also found a sixth area of subsidence in one of the so called accumulation basins next door to the main smooth terrain which hosts the other five areas. That’s been blogged and linked in the same manner.
I know exactly how and why all six areas started subsiding. You could piece it together and write a paper on it if you read the relevant parts of the stretch blog. What’s more, I’d pieced it together before the Groussin et al. paper came out, not as a knee-jerk reaction to make stretch theory fit their findings.
As Marco said in a recent comment to you, we’re finding it hard to get endorsement and there was no interest here in the comments when Marco put out feelers for endorsement. So we’re left in a situation where we’ve been trying to persuade the mainstream of the validity of our ideas for two years, been told officially by Dr. Massironi, representing OSIRIS, that we’re wrong, told to write a paper by you, Gerald and Dr. Massironi, refused endorsement to write it, and are simply waiting now for the inevitable flurry of stretch papers over the next few years that take all the credit and give us none. Somehow I don’t think that sends an encouraging message to future citizen scientists who spend their free time, unpaid, helping to get the science right.
Between us, Marco and I have written nearly eighty blog posts on eighty different aspects of stretch theory. At least fifty have the makings of a scientific paper. They cover all 29km squared of the nucleus except for a small area of the south pole. They do so down to the 10-100 metre scale. Any future stretch paper cannot help but simply repeat what we’ve said already and perhaps tinker a little about the edges.
Hi Ianw16,
The Imhotep plain falling has been the subject of a Rosetta Blog post and linked papers. There was no new information in that mention. However, the boulder movement has neither papers nor Rosetta blog posts. Just a glaring mathematical error, our own discussion on whether boulders can/have moved, and plenty of candidate boulder movements….
IanW: Phil Stooke has good comparison pictures of Imhotep (Oct 2014 vs Aug 2016):
http://www.unmannedspaceflight.com/index.php?act=attach&type=post&id=40036
Thanks Kamal, those are the sort of changes I like; the ones that you can see 🙂