Martian moon Phobos in detail

[alexblackwell]

Martian moon Phobos in detail<br />ESA News Release<br />November 11, 2004

 

[spacechump]

Wow that's cool. Phobos reminds me very much of Phoebe...heck even their spelling is similar.

 

[silylene old]

I thought the streaks were supposed to be stress fractures from a large sub-critical cratering event.<br /><br />I agree Borman, they don't really look much like that. <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center"><em><font color="#0000ff">- - - - - - - - - - - - - - - - - - - - - -</font></em> </div><div class="Discussion_UserSignature" align="center"><font color="#0000ff"><em>I really, really, really miss the "first unread post" function.</em></font> </div> </div>

 

[yurkin]

Its seems a little too structured. All the lines seem to evenly spaced. A wonder if an impact happened before Phobos showed up. And then the impact was big enough to generate a ring system around Mars. A fairly developed ring system with the rings evenly spaced. Then Phobos showed up ran right across the ring system. The change in velocity caused Phobos caused by Phobos’ impact on the rings caused Phobos to enter orbit. It also gave it that nice pattern. Phobos could have been a quasi moon that had only gotten that close to mars every 50 thousand years or so.

 

[grooble]

Its a really nice picture, best yet.

 

[earthseed]

The streaks clearly extend into the craters. It is hard to imagine any external event that could produce such a pattern. It looks to me like a huge hunk of sedimentary rock that was blasted off from somewhere. I would like to see a picture of its other side.<br /><br />But where would you get the 20 km of sedimentary rock required to create such an object?

 

[silylene old]

Well that picture is my new wallpaper, replacing Phoebe.<br /><br />The coloring on this photo was rather realistic. Where was Andy? <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center"><em><font color="#0000ff">- - - - - - - - - - - - - - - - - - - - - -</font></em> </div><div class="Discussion_UserSignature" align="center"><font color="#0000ff"><em>I really, really, really miss the "first unread post" function.</em></font> </div> </div>

 

[jmilsom]

Amazing photo - interesting article.<br /><br />I find it interesting that Phobos was 5km ahead of its projected position, and that this may mean that its "death spiral" is accelerating.<br /><br />What are the best predictions for a Phobos impact or breakup? Thousands, millions of years? What sort of damage would it do if it hit the surface? <div class="Discussion_UserSignature"> </div>

 

[thinice]

http://www.esa.int/SPECIALS/Mars_Express/SEM21TVJD1E_1.html<br /><br />Wow.

 

[omegamogo]

Great picture, thanks!<br />

 

[grooble]

mmm, Potatoe! <br /><br />Wow i just became a ROCK, ah the irony!

 

[the_ten]

^^ haha!

 

[ilbasso]

and in 3D -<br />http://www.esa.int/SPECIALS/Mars_Express/SEM21TVJD1E_1.html#subhead2

 

[alexblackwell]

The Groovy Moon of Mars: Phobos As Seen By Mars Express<br />by Emily Lakdawalla<br />The Planetary Society<br />November 12, 2004

 

[alexblackwell]

<i>I find it interesting that Phobos was 5km ahead of its projected position, and that this may mean that its "death spiral" is accelerating.</i><br /><br />Either that or ESA miscalculated the ephemeris for Phobos and/or Mars Express. I'm not sure what the rate of change for Phobos' well-known secular acceleration is (<i>i.e</i>., whether 5 km is within the bounds of error) but I don't believe the Mars Global Surveyor MOC team experienced any surprises in "finding Phobos where it should be" during their imaging attempts nor do I believe that Mars Pathfinder or the twin MERs reported any deviations in Phobos' position when imaging the moon from the Martian surface.

 

[decepticon]

Lets just say PHOBOS hit mars today, What kind of impact would this rock have on Mars?<br /><br />Could it cause Mars to Warm up or go into a greater deep frezze than it already is in?

 

[alexblackwell]

<i>What remains to be checked out is whether the elements of the moon's orbit allow the double intersection within physically viable mechanics.</i><br /><br />This quickly begins to delve into <i>the</i> main question regarding Phobos and Deimos -- namely their origins. The two main models are (1) the two moons are captured asteroids or (2) they co-accreted with Mars. Not surprisingly, there is evidence to support both. However, while both models have attractive components, they also have some rather glaring holes.<br /><br />For a more rigorous treatment of the subject, I would refer the reader to Joe Burns's chapter in the classic reference work <i>Mars</i> [H.H. Kieffer <i>et al</i>., Eds. (Univ. of Arizona Press, Tucson, AZ, 1992)], which, while slightly dated being published in 1992, is still <i>de rigueur</i> reading on anything related to Mars.<br /><br />At first glance, the "captured asteroids" model seems to be the more attractive of the two. The two moons, for all intents and purposes, do "look" like asteroids. And the close proximity of the asteroidal main belt offers a convenient source. That said, however, even first order observations supporting this view are somewhat puzzling. For example, the spectra of the leading hemisphere of Phobos (<i>i.e</i>., the Stickney-dominated region) best fit the curves for T-class asteroids. On the other hand, Phobos' trailing hemisphere (and, incidentally, Deimos' leading hemisphere) match spectra from D-class asteroids.<br /> <br />Even assuming these spectral observations are truly indicative of captured asteroids, as Burns points out there are problems the capture mechanism. With aerocapture, presumably by the primordial Martian nebula or proto-Mars atmosphere, the problem is not so much with its <i>mechanics</i>, which, though problematical, can be made to work, but rather with its <i>timing</i>. Moreover, capture scenarios should, ideally, show a goo

 

[bonzelite]

<font color="yellow"><br />The long streaks seem externally generated. They don’t seem to be crater streaks unless the moon picked up relative speed to debris from a prior impact. They seem too deep to attribute to atmosphere stripped from Mars during a solar storm. </font><br /><br />right. and so far ignored, too, are perfectly linear displays of multi-pitting/cratering --structures that are in perfect lines composed of uniformly tiny craters, like a dotted line to sign your name on --some portions of the lines are acutally lines of tiny craters. <br /><br />closer examination resolves ever thinner and finer lines between the larger and more visually obvious ones --the surface resembles an etched appearance, as on a phonograph record or on pitted and grooved metal. <br /><br />except for the larger craters that resemble traditional impact basin structures with rims/ramparts, the linear pitting and grooving, at least to me, seems completely created from an external piece of hanidwork diassociated with impact events --the tiny craters all in a row and the fine linear features seem to be the same structure-- created by the same force.

 

[telfrow]

<font color="yellow">except for the larger craters that resemble traditional impact basin structures with rims/ramparts, the linear pitting and grooving, at least to me, seems completely created from an external piece of hanidwork diassociated with impact events --the tiny craters all in a row and the fine linear features seem to be the same structure-- created by the same force.</font><br /><br />Why not just come out and say it, bonzelite? <img src="/images/icons/rolleyes.gif" /> <br /> <div class="Discussion_UserSignature"> <strong><font color="#3366ff">Made weak by time and fate, but strong in will to strive, to seek, to find and not to yeild.</font> - <font color="#3366ff"><em>Tennyson</em></font></strong> </div>

 

[bonzelite]

because i don't have any idea how the structures were created. <br /><br />from visual scrutiny, the linear striations and many --if not all-- dotted line structures appear to be components of the same structure and process. the fine lines and the dotted lines of craters were made by the <b>same</b> process. <br /><br />i'm not committing to that process --just like a politician <img src="/images/icons/blush.gif" /><br />i need to retain some semblance of layman credibility here <img src="/images/icons/crazy.gif" /><br /><br />i like your humor, by the way. i laughed when i read your post. in a good way. really, i don't know how they were made. <br />

 

[telfrow]

Just a little good natured teasing, bonz. <img src="/images/icons/wink.gif" /> <div class="Discussion_UserSignature"> <strong><font color="#3366ff">Made weak by time and fate, but strong in will to strive, to seek, to find and not to yeild.</font> - <font color="#3366ff"><em>Tennyson</em></font></strong> </div>

 

[bonzelite]

it's all good <img src="/images/icons/smile.gif" />

 

[mlorrey]

Well, I don't mind suggesting it, because I can be objective and don't know one way or the other: last week, in my exasperation at some of the nutty "alien civ. on Mars" threads, I though that if an alien civilization ever arose on Mars way long ago, and achieved space travel, one of the things they'd do is mine regolith on Phobos... the grooves look to me like someone drove a snowplow truck all over the moon digging up dirt to feed to a mining vessel... Of course that is entirely anthromorphizing and I will say that as of yet there are no indications of any actual structures on Phobos, but they, if they existed, could have been blasted at some time in the past by an impact that could have knocked Phobos out of a areosynchronous orbit and into its decaying orbit.<br /><br />At this point, I will say for sure that the groove sure are interesting, and I hope to someday get a chance to investigate them in person. Until I find an alien device or evidence of tool use of some kind there, I don't know one way or the other and all this is just speculation...

 

[bonzelite]

yes, i know what you mean. i will reiterate that the structure is <b>one</b> thing --the lateral grooves and the dotted lines of craters are the <b>same</b> structure. so they were created by the same event and the same force. for me, this tableaux of lines in no way elicits --in any fashion-- impact origin. it would nearly be like saying, to make an extreme and absurdist analogue, that a cashmere sweater shows evidence of an impact event in creating it's structure. it makes no sense. no impact created those groves and the lines of tiny craters. i see no point to hold on to the idea of impact in this case. in other cases, sure. for this, no. time to put on another hat <img src="/images/icons/wink.gif" /> <br /><br />and again i have no idea what could have made it. it doesn't really resemble any other marking structure in the solar system that i am aware of. indeed, crater chains are on our moon, but i don't think in conjunction with a geometrically perfectly refined swath of parrallel lines of varying widths that are one and the same structure with the cratering lines. if there is a lunar equivalent, lead me to the data. i'd like to compare and contrast these structures, then. <br /><br />phobos is more mysterious than crop circles or UFOs.

 

[mikeemmert]

It looks like tidal stretching, but it is oriented in the wrong direction. The photo's caption states that this is the hemisphere facing Mars and so the striations would look like bullseyes in the tidal stretching model. Reorientation of the object doesn't work either because Phobos has been spiraling in and is probably now closer to Mars than it has ever been and so new striations would appear that resemble bullseyes.<br /><br />I'm stumped.