19 October, Comet Siding Springs closest to Mars

• by JeanTate

  This NASA webpage seems to have it all, concerning the 19th of October 'close encounter of the comet kind'. Should be kinda fun to see images of a comet, close to Mars, taken by 'observers' on (or near) Mars! 😃

  (I used Search to see if there were other threads on this already. and it had one hit, from quite some time ago. However, when I clicked on the link, nothing happened 😦)

  Posted October 16, 2014 1:46 PM

• by mschwamb scientist, translator

  It's the closest that an Oort cloud comet has come to that close to a terrestrial planet that humanity knew about. All the Mars missions both orbiter and ground-based will be trying to do observations. There was also plenty of lead time which made mobilizing these resources possible. The HiRISE camera that takes the images we use on Planet Four will be trying to image the comet nucleus. It should get a few pixels resolution. For comet ISON where they first attempted, it was actually HiRISE that put the best limit on the size of the nucleus (even compared to Earth-orbiting Hubble Space Telescope).

  There's a nice write up about all the activities scheduled for the encounter on the Planetary Society blog.

  Cheers,

  ~Meg

  Posted October 19, 2014 3:52 AM

• by mschwamb scientist, translator

  An update on HiRISE and MRO - http://www.jpl.nasa.gov/news/news.php?feature=4344

  Posted October 20, 2014 12:48 AM

• by Kitharode moderator in response to JeanTate's comment.

  Hi Jean. I've only just seen this post even though it says you posted 4 days ago! I replied to Pete's post yesterday, but didn't see yours until now (?) Apologies for the delay 😉

  Thanks for the link.

  Posted October 20, 2014 3:54 PM

• by JeanTate in response to Kitharode's comment.

  No worries! 😃

  I replied to Pete's post yesterday

  Do you mean this one?

  One of the most infuriating things about Talk is that there can be two active threads, even in the same subsection, on the same topic, and even MODERATORs don't realize it! 😦 To be clear, I don't mean these two, or you, or even P4 Talk, but in general. For sure, such things happen in all internet fora, but they seem to be more the rule in Talk than the exception ...

  Back to comets and Mars; it seems it (Comet Sidings Spring) is considerably smaller than the models predicted (the nucleus that is). I wonder to what extent that's due to its unique nature (pristine Oort Cloud object, rather than Kuiper Belt frequent flier)?

  Posted October 21, 2014 9:28 AM

• by Kitharode moderator in response to JeanTate's comment.

  Yep. I replied to Pete's 'Duck and Hide' when I saw it, the mystery is why your post didn't appear here until yesterday even though it was posted 4 days earlier.

  Re two active threads on same subject: I consider myself well and truly told off and I've written a 'must do better' note to myself for the future. 😦

  Interesting question about the comet nucleus. Meg might know something about collision rates and such in Oort/Kuiper areas. The other option is that the astronomers got the model wrong. 😉

  Posted October 21, 2014 3:45 PM

• by p.titchin in response to JeanTate's comment.

  Thanks for the input Jean, I was puzzled, as I had been following the approach of this comet, and could not understand why the P4 site was silent on it. I assumed there were 2 concerns, [1] get some images,[2], get the satellites out of the way of the debris cloud. I eventually put in my short 'heads up' post to see if I had got it all wrong. I got little response, and then, after the pass , a new thread. I hope there are some images, and through other sites, I am assured the orbital assets did indeed 'duck'! and they have performed superbly! Thanks Kith for your expanded post on my thread comment .Musicians feel the music of the spheres! :-)~ Pete

  Posted October 21, 2014 7:18 PM

• by mschwamb scientist, translator in response to p.titchin's comment.

  We have HiRISE team members on Planet Four, but we're a separate entity from them, but we're collaborators with them. So we don't know much details to post (well PI Candy Hansen probably knows but she was likely very busy with the preparations for the event. She's deputy PI of the HiRISE camera).

  HiRISE got some great images of the comet. It did resolve the nucleus as predicted. These observations will likely be the best limits on the size of the nucleus. If you remember back to comet ISON, HiRISE actually had the best limits on the size of that comet's nucleus (putting it in the size regime where it would be expected to break apart as it did), beating out Hubble Space Telescope.

  Here's the press release from the HiRISE team with the images.

  I'm hoping to write a blog post about this sometime this week. I just got to Oxford for a collaboration visit with some of the Zooniverse folks so we'll see. It might turn into a plane ride task on the way back to Taipei in two weeks.
  Cheers,

  Cheers,

  ~Meg

  Posted October 22, 2014 9:54 AM

• by JeanTate in response to Kitharode's comment.

  Yeah, this is one of the mysteries of Talk (or at least v2 Talk). As I tried to say, I don't think this is your failing, Kitharode, or any MODERATOR's*. And it's not just a problem in P4; I know it occurs in at least several other Zooniverse projects' v2 Talks too.

  @Pete: as I noted in my post, I had tried using Search to find other threads, and got a hit; however, when I clicked on the link, it was blank! This too is an all-too-common problem in v2 Talks (not just in P4). I've given feedback on this - more than once - but it's as if what I wrote went into a black hole; even Darren/DMZ hasn't commented on it. 😮

  But, like you, I was somewhat puzzled that no one had commented on Comet Siding Spring ...

  Back to Mars, and the comet: I'm pretty sure the answer is "no, far too little dust to be seen" (or something like that), but anyway: will the comet deposit enough dust, when it finally settles on polar icy surfaces, to be detected by HiRISE (not in images we get to classify, necessarily)?

  *just in case: I am not SHOUTING! I write MODERATOR (and SCIENTIST, etc) in CAPS because those are your (generic) titles, in v2 Talk; why you need CAPS titles I have no idea, but I consider it somewhat disrespectful (though not rude, exactly) to use titles other than as they're written (calling "the Queen", say, "the queen", or writing "nato chairman", say)

  Posted October 22, 2014 1:12 PM

• by mschwamb scientist, translator in response to JeanTate's comment.

  I was actually going to post about Siding Spring, but you beat me to it Jean 😃. So I commented on your post. It's great to see other people bringing up Mars' events that have a connection to Planet Four.

  In terms of the caps for roles on Talk, it's just a stylistic thing. I personally like the small text and caps because it's noticeable but not in a glaring way. I certainly believe the Zooniverse means no disrespect by it.

  The dust coming off the comet is in small particulates, I'm not sure any would survive entry from the atmosphere to make it to the surface of the south pole let around anywhere else on the Planet. Maybe some would still be in the very upper upper atmosphere (planetary atmospheres are not be expertise), MAVEN (NASA's new orbiter around Mars ) should be able to help answer that question.

  Cheers,

  ~Meg

  Posted October 22, 2014 2:06 PM

• by JeanTate in response to mschwamb's comment.

  Thanks Meg.

  I'm not sure any would survive entry from the atmosphere to make it to the surface of the south pole

  Hmm ... I'm somewhat puzzled by that ... don't tons and tons of fine particulate matter daily survive entry into the Earth's atmosphere (micrometeorites)? And don't Greenland, Antartica, etc ice cores contain considerable quantities of dust derived - ultimtately - from asteroids and comets? The difference, on Mars, would be that there's essentially no weathering, and unless the pole is hit by a dust storm, extra-Martian (?) dust should show up nicely on fresh 'snow' ... of course, Siding Spring may well - very likely - have left so little dust it'd be nigh on impossible to detect, even by an on-site lander.

  Posted October 22, 2014 2:40 PM

• by p.titchin in response to mschwamb's comment.

  Nice to see my short post produced results. Thanks Jean. 😃 - Pete

  Posted October 22, 2014 7:26 PM

• by Kitharode moderator in response to JeanTate's comment.

  As you probably already know, the micrometeorites you mention don't come down to Earth like a 'regular' meteorite, ie whizz-flash-splat. The meteoritic dust is caught in the atmosphere and settles gently onto the surface over time. So I reckon you're right about the fine particulates surviving to enter the Earth's atmosphere, but I've a feeling that Meg is referring to the 'bulky' stuff in the comet's tail which would most likely not survive.

  Whatever - Meg can speak for herself. 😉

  Here's a silly question to play with: Meteoroid = space dust floating about. Meteor = space dust burning in atmosphere. Meteorite = space dust that survives to hit surface. So should we be talking about meteoroidal dust, or does meteoritic dust still apply? 😉

  Posted October 22, 2014 10:14 PM

• by wassock moderator

  Speaking from a position of not having researched this, I had assumed that dust which gets caught by the atmosphere is basically colloidal and or on a near glancing tragectory anything bigger or coming steeper gets heated by atmospher and burns, becoming smaller bits/ dust and gaseous products of heating.

  Either way the problem is that the pole is already pretty dusty and so even if you took a kilometer sized object, turned it to dust and spread it evenly, its unlikely that you'd notice. But as discussed here some while ago a far chunk of the surface material must be extra Mars - ses me

  Posted October 23, 2014 12:30 AM

• by Kitharode moderator

  Wassock's extra-martian dust discussion is here: http://talk.planetfour.org/#/boards/BPF0000006/discussions/DPF0000cas

  Posted October 23, 2014 2:39 PM

• by mschwamb scientist, translator

  I thought this would be of interest,

  Cheers,
  ~Meg

  Posted October 24, 2014 12:15 AM

• by wassock moderator

  Looks like a fairly regular cycle of dust levels, with the one excursion. Looks like levels are higer when the South is un iced?

  Posted October 25, 2014 12:51 AM

• by wassock moderator

  Further to the "dust from space thing" take a look at this http://vimeo.com/110535098 checkout the 'smoke ring'

  Posted November 3, 2014 10:07 AM

• by Kitharode moderator in response to wassock's comment.

  No comment - But only because Vimeo never works on my laptop. 😦

  Posted November 3, 2014 1:11 PM

• by angi60 in response to wassock's comment.

  Wow, that's amazing! 😃

  Posted November 6, 2014 12:48 AM

• by wassock moderator in response to Kitharode's comment.

  Kith it's a vid someone took of the milky way. Something like 120 30 sec exposures animated.

  You see a brief meteor trail which then explodes and throws a 'smoke ring' of debris

  Posted November 6, 2014 1:27 PM

• by mschwamb scientist, translator

  I saw this article and thought of this conversation.

  Cheers,

  ~Meg

  Posted December 7, 2014 5:20 AM