# The 'Jelly Donut' rock on Mars **URL:** \ **Category:** Miscellaneous and Personal Stuff I Must Share\ **Created:** [January 20, 2014, 9:20pm UTC](https://boards.straightdope.com/t/the-jelly-donut-rock-on-mars/679311 "2014-01-20T21:20:19Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [January 20, 2014, 9:20pm UTC](https://boards.straightdope.com/t/the-jelly-donut-rock-on-mars/679311/1 "2014-01-20T21:20:19Z")
Just stumbled across this quite interesting story today - a rock just ‘appeared’ next to the Opportunity rover on mars. [Story link](http://www.businessinsider.com.au/mystery-mars-rock-appears-near-opportunity-rover-2014-1) (the best one I could find for image quality) My first thought was: doesn’t it look like there is quite a close correlation between the shape of that mark on the ground (in the first image) and the shape of the rock that eventually appears on top of it? And I couldn’t help thinking of [Limpet scars](http://www.marine-reserve.co.uk/wp-content/uploads/2012/02/Limpet-1.jpg) But really, despite the sudden appearance and the strange composition of this thing, I’m not seriously suggesting it’s a living thing. But WTF is going on here? ---
**Author:** ![Balance](https://avatars.discourse-cdn.com/v4/letter/b/ccd318/32.png) [@Balance](https://boards.straightdope.com/u/Balance)\ **Post date:** [January 20, 2014, 9:32pm UTC](https://boards.straightdope.com/t/the-jelly-donut-rock-on-mars/679311/2 "2014-01-20T21:32:34Z")
The current best guess appears to be that the rock was kicked up by a dragging wheel on the rover. One of the wheels is partially locked up–it will rotate, but not pivot, so when the rover changes direction, it drags that wheel sideways across the ground. ---
**Author:** ![JohnT](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnt/32/15048_2.png) [@JohnT](https://boards.straightdope.com/u/JohnT)\ **Post date:** [January 20, 2014, 10:02pm UTC](https://boards.straightdope.com/t/the-jelly-donut-rock-on-mars/679311/3 "2014-01-20T22:02:50Z")
The more amazing thing is that the robot is 9 years, 9 months past its expected shelf life. ---
**Author:** ![dracoi](https://avatars.discourse-cdn.com/v4/letter/d/90db22/32.png) [@dracoi](https://boards.straightdope.com/u/dracoi)\ **Post date:** [January 20, 2014, 10:09pm UTC](https://boards.straightdope.com/t/the-jelly-donut-rock-on-mars/679311/4 "2014-01-20T22:09:18Z")
> [@JohnT](#): > > The more amazing thing is that the robot is 9 years, 9 months past its expected shelf life. Further proof that the government can’t do anything right. 🙂 ---
**Author:** ![ftg](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ftg/32/2801_2.png) [@ftg](https://boards.straightdope.com/u/ftg)\ **Post date:** [January 20, 2014, 10:58pm UTC](https://boards.straightdope.com/t/the-jelly-donut-rock-on-mars/679311/5 "2014-01-20T22:58:11Z")
Already a [thread](http://boards.straightdope.com/sdmb/showthread.php?t=713475). ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [January 20, 2014, 11:51pm UTC](https://boards.straightdope.com/t/the-jelly-donut-rock-on-mars/679311/6 "2014-01-20T23:51:58Z")
I did search before posting, but I searched for _donut_. D’oh. ---
**Author:** ![Joey\_P](https://avatars.discourse-cdn.com/v4/letter/j/919ad9/32.png) [@Joey\_P](https://boards.straightdope.com/u/Joey_P)\ **Post date:** [January 21, 2014, 12:55am UTC](https://boards.straightdope.com/t/the-jelly-donut-rock-on-mars/679311/7 "2014-01-21T00:55:25Z")
I’m surprised that in all this time, they’d even notice an out of place rock. ---
**Author:** ![Moonlitherial](https://avatars.discourse-cdn.com/v4/letter/m/4bbf92/32.png) [@Moonlitherial](https://boards.straightdope.com/u/Moonlitherial)\ **Post date:** [January 21, 2014, 1:07am UTC](https://boards.straightdope.com/t/the-jelly-donut-rock-on-mars/679311/8 "2014-01-21T01:07:39Z")
You underestimate how freaking thrilled the scientists are still almost 10 years after the project was supposed to end they’re still getting new footage. They always knew it was going to last longer, you over engineer to ensure you make the timeline you promised but this is beyond what they hoped for. It’s a sad set of circumstances, projects that worked for years are still delivering but there is very little on the horizon due to budget cuts. Keep going Opportunity, you can do it! ---
**Author:** ![Joey\_P](https://avatars.discourse-cdn.com/v4/letter/j/919ad9/32.png) [@Joey\_P](https://boards.straightdope.com/u/Joey_P)\ **Post date:** [January 21, 2014, 1:16am UTC](https://boards.straightdope.com/t/the-jelly-donut-rock-on-mars/679311/9 "2014-01-21T01:16:00Z")
Obligatory [XKCD](http://xkcd.com/695/) ---
**Author:** ![Sunspace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sunspace/32/1250_2.png) [@Sunspace](https://boards.straightdope.com/u/Sunspace)\ **Post date:** [January 21, 2014, 1:21am UTC](https://boards.straightdope.com/t/the-jelly-donut-rock-on-mars/679311/10 "2014-01-21T01:21:49Z")
> [@Joey\_P](#): > > Obligatory [XKCD](http://xkcd.com/695/) That is the saddest XKCD. ---
**Author:** ![Tabby\_Cat](https://avatars.discourse-cdn.com/v4/letter/t/6a8cbe/32.png) [@Tabby\_Cat](https://boards.straightdope.com/u/Tabby_Cat)\ **Post date:** [January 21, 2014, 2:08am UTC](https://boards.straightdope.com/t/the-jelly-donut-rock-on-mars/679311/11 "2014-01-21T02:08:20Z")
[What the Mars Rover is actually thinking.](http://www.unmannedspaceflight.com/index.php?act=attach&type=post&id=20543) ---
**Author:** ![Sunspace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sunspace/32/1250_2.png) [@Sunspace](https://boards.straightdope.com/u/Sunspace)\ **Post date:** [January 21, 2014, 2:25am UTC](https://boards.straightdope.com/t/the-jelly-donut-rock-on-mars/679311/12 "2014-01-21T02:25:18Z")
> [@Tabby\_Cat](#): > > [What the Mars Rover is actually thinking.](http://www.unmannedspaceflight.com/index.php?act=attach&type=post&id=20543) What a relief. ---
**Author:** ![buddha\_david](https://avatars.discourse-cdn.com/v4/letter/b/ee7513/32.png) [@buddha\_david](https://boards.straightdope.com/u/buddha_david)\ **Post date:** [January 21, 2014, 7:26am UTC](https://boards.straightdope.com/t/the-jelly-donut-rock-on-mars/679311/13 "2014-01-21T07:26:34Z")
Don’t show that one photo to Homer Simpson! ---
**Author:** ![purplehorseshoe](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/purplehorseshoe/32/2996_2.png) [@purplehorseshoe](https://boards.straightdope.com/u/purplehorseshoe)\ **Post date:** [January 22, 2014, 4:36pm UTC](https://boards.straightdope.com/t/the-jelly-donut-rock-on-mars/679311/14 "2014-01-22T16:36:53Z")
> [@Balance](#): > > The current best guess appears to be that the rock was kicked up by a dragging wheel on the rover. One of the wheels is partially locked up–it will rotate, but not pivot, so when the rover changes direction, it drags that wheel sideways across the ground. They made the rover out of a supermarket shopping cart? ---
**Author:** ![EddyTeddyFreddy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eddyteddyfreddy/32/18796_2.png) [@EddyTeddyFreddy](https://boards.straightdope.com/u/EddyTeddyFreddy)\ **Post date:** [January 22, 2014, 5:09pm UTC](https://boards.straightdope.com/t/the-jelly-donut-rock-on-mars/679311/15 "2014-01-22T17:09:09Z")
> [@purplehorseshoe](#): > > They made the rover out of a supermarket shopping cart? 😃 Thanks, I needed a belly laugh today. ---
**Author:** ![terentii](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/terentii/32/212_2.png) [@terentii](https://boards.straightdope.com/u/terentii)\ **Post date:** [January 22, 2014, 5:14pm UTC](https://boards.straightdope.com/t/the-jelly-donut-rock-on-mars/679311/16 "2014-01-22T17:14:11Z")
> [@Balance](#): > > The current best guess appears to be that the rock was kicked up by a dragging wheel on the rover. One of the wheels is partially locked up–it will rotate, but not pivot, so when the rover changes direction, it drags that wheel sideways across the ground. Look closely at the first photo. I think the rock is there, but it’s almost impossible to see because of the angle and lighting. ---
**Author:** ![rjk](https://avatars.discourse-cdn.com/v4/letter/r/ed655f/32.png) [@rjk](https://boards.straightdope.com/u/rjk)\ **Post date:** [January 23, 2014, 6:54am UTC](https://boards.straightdope.com/t/the-jelly-donut-rock-on-mars/679311/17 "2014-01-23T06:54:55Z")
> [@Tabby\_Cat](#): > > [What the Mars Rover is actually thinking.](http://www.unmannedspaceflight.com/index.php?act=attach&type=post&id=20543) So do you have a link to the actual post (or even the thread) that pic is part of? I’d like to see if there’s any background or commentary to go with it. ---
**Author:** ![Tabby\_Cat](https://avatars.discourse-cdn.com/v4/letter/t/6a8cbe/32.png) [@Tabby\_Cat](https://boards.straightdope.com/u/Tabby_Cat)\ **Post date:** [January 23, 2014, 7:51am UTC](https://boards.straightdope.com/t/the-jelly-donut-rock-on-mars/679311/18 "2014-01-23T07:51:39Z")
I got it from this thread, who attributes it to one of the Mars rover drivers, but I didn’t look further back than that. [http://www.unmannedspaceflight.com/index.php?showtopic=6291&st=915&start=915](http://www.unmannedspaceflight.com/index.php?showtopic=6291&st=915&start=915) ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [January 23, 2014, 8:11am UTC](https://boards.straightdope.com/t/the-jelly-donut-rock-on-mars/679311/19 "2014-01-23T08:11:39Z")
> [@terentii](#): > > Look closely at the first photo. I think the rock is there, but it’s almost impossible to see because of the angle and lighting. That’s what struck me. In the first photo, there’s already something there that looks the exact shape and size of the rock, but it \*looks \*flat. Could it just be that the thing was always there - previously coated in dust and has been blown clean by wind, or that it has changed colour due to some surface chemical process such as a thin bloom of salt crystals? ---
**Author:** ![Bumbershoot](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bumbershoot/32/3428_2.png) [@Bumbershoot](https://boards.straightdope.com/u/Bumbershoot)\ **Post date:** [January 23, 2014, 12:22pm UTC](https://boards.straightdope.com/t/the-jelly-donut-rock-on-mars/679311/20 "2014-01-23T12:22:25Z")
> [@terentii](#): > > Look closely at the first photo. I think the rock is there, but it’s almost impossible to see because of the angle and lighting. I don’t know; look at the B&W photo in [this article](http://news.discovery.com/space/mystery-rock-appears-in-front-of-mars-rover-140117.htm) (from [the other “donut rock” thread](http://boards.straightdope.com/sdmb/showthread.php?t=713475)). It sure looks like there is something in the second photo that isn’t in the first one. [Next page](https://boards.straightdope.com/t/the-jelly-donut-rock-on-mars/679311.md?page=2)