# Can NASA be trusted to tell us the true color of Mars? **URL:** \ **Category:** Great Debates\ **Created:** [January 3, 2003, 4:32pm UTC](https://boards.straightdope.com/t/can-nasa-be-trusted-to-tell-us-the-true-color-of-mars/146438 "2003-01-03T16:32:07Z")\ **Posts on this page:** 20\ **Page:** 3
**Author:** ![Tuckerfan](https://avatars.discourse-cdn.com/v4/letter/t/eada6e/32.png) [@Tuckerfan](https://boards.straightdope.com/u/Tuckerfan)\ **Post date:** [January 5, 2003, 9:52pm UTC](https://boards.straightdope.com/t/can-nasa-be-trusted-to-tell-us-the-true-color-of-mars/146438/41 "2003-01-05T21:52:20Z")
> [@](#): > > \*Originally posted by GOM \* > \*\*hmmm > > I missed that. What probes are you talking about? \*\* Back in the early 1990’s (exact dates escape me) Hoagland stated that he had a deal with someone to launch probes to the Moon to do close up flybys of the various monuments which Hoagland swears are there (including a mile high tower on the far side), they were supposed to be done before either the 1992 or 1996 elections and we’d all be able to watch the proceedings live on pay-per-view. Didn’t happen and Hoagland ain’t said a word about it since then. Draw your own conclusions. Of course, I work for Old Navy, so my comments are suspect on the matter. (After all, we’re part of the “grand conspiracy” to hide the aliens! :rolleyes: ) ---
**Author:** ![Podkayne](https://avatars.discourse-cdn.com/v4/letter/p/edb3f5/32.png) [@Podkayne](https://boards.straightdope.com/u/Podkayne)\ **Post date:** [January 5, 2003, 10:46pm UTC](https://boards.straightdope.com/t/can-nasa-be-trusted-to-tell-us-the-true-color-of-mars/146438/42 "2003-01-05T22:46:50Z")
When astronomers compare Mars to an Arizona desert, they are referring to the sand, scattered with rocks. I’m almost certain that Sagan has numerous papers on Mars spectroscopy, demonstrating that the Red Planet is . . . GREEN! YES GREEN! It’s all a plot!!! Er, um, yeah, uh, actually, I mean, red. If you want, I can look them up for you and reproduce the abstracts here. Interestingly, there has never been a lander on Mars that had _good_ color and spectroscopic calibration. There have always been unanticipated problems–no lab spectrum, no calibration targets on the craft, unresolved questions about dust in the air, and, in the case of Pathfinder, dust accumulation on the calibration targets. (Once again, if NASA was faking it all, why would they make it _so damn hard_?) The images you linked to, **GOM** , were not intended to represent the “true” color of Mars. The Mars Observer image is obviously grey scale, for crying out loud. If any idiot with a 10 inch telescope in his back yard can measure the color of Mars, what could NASA possibly gain by attempting to mislead the public on this topic? ---
**Author:** ![Liberal](https://avatars.discourse-cdn.com/v4/letter/l/848f3c/32.png) [@Liberal](https://boards.straightdope.com/u/Liberal)\ **Post date:** [January 5, 2003, 10:50pm UTC](https://boards.straightdope.com/t/can-nasa-be-trusted-to-tell-us-the-true-color-of-mars/146438/43 "2003-01-05T22:50:09Z")
> [@](#): > > \*Originally posted by Duck Duck Goose \* > \*\*No, no, you done good, sweetie, show’s over, thanks to you. 🆒 \*\* I agree. Podkayne presented a compelling argument aimed directly at the OPs assertions that should have convinced any reasonable person. This debate is over. ---
**Author:** ![Ben](https://avatars.discourse-cdn.com/v4/letter/b/df788c/32.png) [@Ben](https://boards.straightdope.com/u/Ben)\ **Post date:** [January 6, 2003, 1:49am UTC](https://boards.straightdope.com/t/can-nasa-be-trusted-to-tell-us-the-true-color-of-mars/146438/44 "2003-01-06T01:49:42Z")
> [@](#): > > \*Originally posted by GOM \* > \*\*Maybe another thread would be better for the “aliens”. \*\* [sure thing.](http://boards.straightdope.com/sdmb/showthread.php?threadid=154617) ---
**Author:** ![asrivkin](https://avatars.discourse-cdn.com/v4/letter/a/9d8465/32.png) [@asrivkin](https://boards.straightdope.com/u/asrivkin)\ **Post date:** [January 6, 2003, 2:09am UTC](https://boards.straightdope.com/t/can-nasa-be-trusted-to-tell-us-the-true-color-of-mars/146438/45 "2003-01-06T02:09:30Z")
Right. I am, actually, a planetary astronomer. Not that that means I’m infallible on this. 🙂 A major problem with getting true color from _any_ spacecraft is that the filters used are primarily chosen for scientific reasons, and getting “realistic to the eyes” color from them is a bit kludgey. IIRC, the Viking landers only had two filters in the visible, one sorta at the UV end of blue, the other orange, more-or-less. To get color out of that, you have to make weighted averages out of an IR filter and an orange filter (say) to get red, and so on. And even then, since your “red”, “green” and “blue” are dependent on those mathematical mixtures of other images, you’re as likely as not going to be off. While Viking has those problems most obviously, I can’t think of a single planetary mission with real “true color” capability. This is in addition to aforementioned issues like filtering sunlight through a dust-filled martian atmosphere instead of a relatively-clear terrestrial one, and which case you count as “true color”. There is a straightforward way for those concerned to find out the “true color” of Mars: invest in a telescope, get a CCD with a filter wheel and filters designed for true color images, and point it at Mars. I suspect your results will match the various NASA results within statistical variation… ---
**Author:** ![Podkayne](https://avatars.discourse-cdn.com/v4/letter/p/edb3f5/32.png) [@Podkayne](https://boards.straightdope.com/u/Podkayne)\ **Post date:** [January 6, 2003, 3:00am UTC](https://boards.straightdope.com/t/can-nasa-be-trusted-to-tell-us-the-true-color-of-mars/146438/46 "2003-01-06T03:00:10Z")
Hi, **asrivkin**! I don’t think we’ve met IRL, but I’ve been sleeping with one of your papers under my pillow while writing my thesis. 🙂 ---
**Author:** ![GOM](https://avatars.discourse-cdn.com/v4/letter/g/5f9b8f/32.png) [@GOM](https://boards.straightdope.com/u/GOM)\ **Post date:** [January 6, 2003, 3:27am UTC](https://boards.straightdope.com/t/can-nasa-be-trusted-to-tell-us-the-true-color-of-mars/146438/47 "2003-01-06T03:27:45Z")
> [@](#): > > \*Originally posted by asrivkin \* > \*\*Right. I am, actually, a planetary astronomer. Not that that means I’m infallible on this. 🙂 > > \*\* Cool! Pleasure to “meet” you. ---
**Author:** ![asrivkin](https://avatars.discourse-cdn.com/v4/letter/a/9d8465/32.png) [@asrivkin](https://boards.straightdope.com/u/asrivkin)\ **Post date:** [January 6, 2003, 3:37pm UTC](https://boards.straightdope.com/t/can-nasa-be-trusted-to-tell-us-the-true-color-of-mars/146438/48 "2003-01-06T15:37:36Z")
> [@](#): > > \*Originally posted by Podkayne \* > \*\*Hi, **asrivkin**! I don’t think we’ve met IRL, but I’ve been sleeping with one of your papers under my pillow while writing my thesis. 🙂 \*\* Oh-oh. Which one? I wrote them all when I was drunk, you know. 😉 ---
**Author:** ![GOM](https://avatars.discourse-cdn.com/v4/letter/g/5f9b8f/32.png) [@GOM](https://boards.straightdope.com/u/GOM)\ **Post date:** [January 6, 2003, 7:02pm UTC](https://boards.straightdope.com/t/can-nasa-be-trusted-to-tell-us-the-true-color-of-mars/146438/49 "2003-01-06T19:02:24Z")
> [@](#): > > \*Originally posted by Podkayne \* > \*\*The Mars Observer image is obviously grey scale, for crying out loud. \*\* Yep. I was hoping at least **one** person would take a look at the link. Thanks. ---
**Author:** ![GOM](https://avatars.discourse-cdn.com/v4/letter/g/5f9b8f/32.png) [@GOM](https://boards.straightdope.com/u/GOM)\ **Post date:** [January 6, 2003, 7:06pm UTC](https://boards.straightdope.com/t/can-nasa-be-trusted-to-tell-us-the-true-color-of-mars/146438/50 "2003-01-06T19:06:25Z")
> [@](#): > > \*Originally posted by Podkayne \* > \*\*1. I think images should be clearly labeled as “false color,” or “‘true color’” in quotes or “approximately true color,” but that’s just me. > > 1. It’s kind of amusing for me to hear these people who insinuate that the space program is a sham, because, geez, I work with HST images all the time, and just down the hall are the guys analyzing images from Mars Climate Orbiter and up one floor from the guys designing the next mission to God knows where . . . > > 2. I mean, space exploration is as banal and routine as last week’s grocery list to me, \* \*\* 1. I like your suggestion. 2. Do you work for NASA? Or a NASA contractor? 3. I’m sorry to hear that. 33 years ago space was **exciting**! ---
**Author:** ![Podkayne](https://avatars.discourse-cdn.com/v4/letter/p/edb3f5/32.png) [@Podkayne](https://boards.straightdope.com/u/Podkayne)\ **Post date:** [January 6, 2003, 7:09pm UTC](https://boards.straightdope.com/t/can-nasa-be-trusted-to-tell-us-the-true-color-of-mars/146438/51 "2003-01-06T19:09:41Z")
> [@](#): > > \*Originally posted by asrivkin \* > \*\*Oh-oh. Which one? I wrote them all when I was drunk, you know. 😉 \*\* You’re second author, so I imagine that Amanda kept you in line. 🙂 It’s the Saturn pole precession one. I’ve also been reading some of your F ring stuff. ---
**Author:** ![GOM](https://avatars.discourse-cdn.com/v4/letter/g/5f9b8f/32.png) [@GOM](https://boards.straightdope.com/u/GOM)\ **Post date:** [January 6, 2003, 7:13pm UTC](https://boards.straightdope.com/t/can-nasa-be-trusted-to-tell-us-the-true-color-of-mars/146438/52 "2003-01-06T19:13:48Z")
> [@](#): > > \*Originally posted by Attrayant \* > \*\* > Were Sagan’s comments no more detailed than that? And why is he necessarily speaking about just the color? Tint those pictures green, blue or fuschia and it still looks a lot like a desert. \*\* Yes. Apparently they were somewhat more detailed, as the story was told. He commented on the salmon color of the ground and on the blue sky. I’m not exactly sure about the significance of the salmon color. I’ve seen lots of soil in Arizone that is reddish, but I don’t know exactly where salmon fits in the color chart. It sounds towards the pink side, to me. And I agree that it would still look like a desert with any color. It’s possible that the salmon color is what you get when the sky is shown as blue. I think the key point might be that NASA does not want to show any blue sky. I need to look into it further. ---
**Author:** ![Duck\_Duck\_Goose](https://avatars.discourse-cdn.com/v4/letter/d/50afbb/32.png) [@Duck\_Duck\_Goose](https://boards.straightdope.com/u/Duck_Duck_Goose)\ **Post date:** [January 6, 2003, 7:35pm UTC](https://boards.straightdope.com/t/can-nasa-be-trusted-to-tell-us-the-true-color-of-mars/146438/53 "2003-01-06T19:35:47Z")
I don’t think GOM has noticed Ben’s thread for him, as it’s down at the bottom of the forum. [GOM’s alien conspiracy theory](http://boards.straightdope.com/sdmb/showthread.php?threadid=154617) ---
**Author:** ![dalovindj](https://avatars.discourse-cdn.com/v4/letter/d/65b543/32.png) [@dalovindj](https://boards.straightdope.com/u/dalovindj)\ **Post date:** [January 6, 2003, 8:05pm UTC](https://boards.straightdope.com/t/can-nasa-be-trusted-to-tell-us-the-true-color-of-mars/146438/54 "2003-01-06T20:05:04Z")
> [@](#): > > If there is no way to settle who is right and who is wrong, then the reasonable thing to do is to postone making a conclusion. I agree. So many people can’t see this simple truth. Especially when it comes to religion. DaLovin’ Dj ---
**Author:** ![Ben](https://avatars.discourse-cdn.com/v4/letter/b/df788c/32.png) [@Ben](https://boards.straightdope.com/u/Ben)\ **Post date:** [January 6, 2003, 8:20pm UTC](https://boards.straightdope.com/t/can-nasa-be-trusted-to-tell-us-the-true-color-of-mars/146438/55 "2003-01-06T20:20:43Z")
FWIW, I seem to remember an essay by Sagan (perhaps in \_The Cosmic Connection) talking about the first Viking photos from the surface of Mars. The color technicians saw the red sky, and said, “That doesn’t look right!” and adjusted it to be blue. (IIRC, this made the sand and rock look salmon, rather than its true rust-red/brown color.) When some planetary scientists saw the pictures, they spotted the error and from that point on the color was carefully adjusted using the color reference on Viking, and without regard for anyone’s expectations about what the sky “should” look like. (You can actually see the color reference in some of the pictures reproduced in _Cosmos,_ btw.) A similar story is told about the green women from Star Trek. The first test shots of women in the green makeup kept coming out flesh-colored when developed. Roddenberry kept demanding greener and greener makeup, until he realized that the photo lab was adjusting the skin color to look normal on the assumption that the green color was a problem with the film. ---
**Author:** ![Podkayne](https://avatars.discourse-cdn.com/v4/letter/p/edb3f5/32.png) [@Podkayne](https://boards.straightdope.com/u/Podkayne)\ **Post date:** [January 6, 2003, 9:27pm UTC](https://boards.straightdope.com/t/can-nasa-be-trusted-to-tell-us-the-true-color-of-mars/146438/56 "2003-01-06T21:27:08Z")
> [@](#): > > _Originally posted by GOM \* > \*\* I think the key point might be that NASA does not want to show any blue sky._\* “NASA” isn’t a monolithic entity. “NASA” doesn’t process images and “NASA” doesn’t say what color Mars is or what color the sky should be portrayed as. _Scientists_ who work for NASA figure this stuff out. They aren’t at the mercy of some all-powerful NASA censor who tells them what they should say. They do their best to accurately interpret their data (data from instruments that _they_ helped to design and build). They put out press releases (some of them through the NASA press offices, admittedly, but some of them through their university press offices.) They publish papers in the scientific literature without getting a yea or nay from “NASA”. Which brings up another point: there _is_ in fact a scientific literature, which, for some reason, the Face-on-Mars/ET loonies tend to ignore even more completely than the Creationists do. There is a vast amount of information out there, constantly under review by other scientists. If the data really say that the sky on Mars is blue and Mars is really some other color than its widely-accepted orangey-reddish-rusty color, then any papers that claim it’s not should have flaws in them that are apparent to other trained scientists. Which is most likely to be true? 1. _All_ scientists are somehow controlled by the evil NASA censors who are trying to keep the truth from the American People, so that for thirty years _every_ scientist remotely connected to the Mars program has lied about the color of Mars. Not a single scientist has dared to offer the dissenting view. Mars, as observed by the naked eye, has been considered to be red since ancient times (go outside and _look_, for crimeny’s sake; it’s in the southeast around dawn, near Venus and the aptly-named red star, Antares, the “rival of Mars”). Telescopic observations since the time of _Galileo Galilei_ have unanimously shown it to be red. The minerals on the surface of Mars have been analyzed by the landers and have been found to contain highly oxidized iron compounds that are red. Have all these facts been manufactured or manipulated, because Mars is, in fact, not red? Note please that this means that I, and **asrivkin,** and all our colleagues are _lying_, participating in a massive conspiracy to supress the truth, the exact opposite of what a good scientist is supposed to do. If this is your favorite explanation, please let me know so I can cease wasting my time trying to convince you of anything, given that, if you believe this explanation, you believe I am a liar. 2. Only _some_ of the scientists are controlled by evil NASA censors. The rest of the scientists are just too stupid to notice that thirty years of heavily scrutinized self-consistent spacecraft data, not to mention centuries of ground-based data, have been massively cooked to make it _seem_ like Mars is red, when it’s actually the exact same color of some unspecified patch of Arizona desert. Please note that if this is your favorite explanation, that makes **asrivkin** , me, and the rest either _incompetents_ or liars. Once again, please let me know if that’s your belief, so I can stop wasting my time. 3. Mars may, in fact, possibly be actually RED. The Viking mishap was a screw-up caused by inexperience and rectified as soon as it was understood. The sky observed by Viking and Pathfinder was pink. It may or may not be pink all the time at all locations–we don’t really understand it yet. Again, if this was some kind of an airtight conspiracy, it seems weird that there are so many loose ends. The better explanation might be that exploring Mars is _hard_ and we haven’t figured it all out yet. ---
**Author:** ![Cervaise](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cervaise/32/16693_2.png) [@Cervaise](https://boards.straightdope.com/u/Cervaise)\ **Post date:** [January 6, 2003, 10:59pm UTC](https://boards.straightdope.com/t/can-nasa-be-trusted-to-tell-us-the-true-color-of-mars/146438/57 "2003-01-06T22:59:13Z")
1. All of this is disinformation that is somehow making it through the tinfoil. La la la la la la la, I can’t hear you, la la la la… ---
**Author:** ![GOM](https://avatars.discourse-cdn.com/v4/letter/g/5f9b8f/32.png) [@GOM](https://boards.straightdope.com/u/GOM)\ **Post date:** [January 7, 2003, 5:07pm UTC](https://boards.straightdope.com/t/can-nasa-be-trusted-to-tell-us-the-true-color-of-mars/146438/58 "2003-01-07T17:07:54Z")
Two more cents worth on Mars. There’s an intriguing thread about the color of the soil at the Pathfinder landing site over here: [http://www.marsnews.com/phpBB/phpBB2/viewtopic.php?t=96](http://www.marsnews.com/phpBB/phpBB2/viewtopic.php?t=96) I see I need to respond to a few of you, but right now Straighdope is loading painfully slow for me, even using a cable modem. I’ll check back later to see if I can get through with having to wait fifteen minutes to post. In the meantime some of you might find it interesting about the two pix of Sojourner (shown in the linked thread) that were allegedly taken five days apart. The color is different, but the rover appears to be in exactly the same position. One of those things that, if you’re curious, kinda makes ya go: hmmmmm. Later. ---
**Author:** ![tracer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tracer/32/20578_2.png) [@tracer](https://boards.straightdope.com/u/tracer)\ **Post date:** [January 7, 2003, 6:51pm UTC](https://boards.straightdope.com/t/can-nasa-be-trusted-to-tell-us-the-true-color-of-mars/146438/59 "2003-01-07T18:51:46Z")
> [@](#): > > \*Originally posted by GOM \* > **In the meantime some of you might find it interesting about the two pix of Sojourner (shown in the linked thread) that were allegedly taken five days apart. The color is different, but the rover appears to be in exactly the same position. One of those things that, if you’re curious, kinda makes ya go: hmmmmm.** Yeah – and did you notice how the two pitures of the Sojourner at the bottom of the thread were **black-and-white**? Clearly, these pictures prove that Mars is gray, not red! Why has NASA been covering this up? ---
**Author:** ![BMalion](https://avatars.discourse-cdn.com/v4/letter/b/e274bd/32.png) [@BMalion](https://boards.straightdope.com/u/BMalion)\ **Post date:** [January 7, 2003, 7:31pm UTC](https://boards.straightdope.com/t/can-nasa-be-trusted-to-tell-us-the-true-color-of-mars/146438/60 "2003-01-07T19:31:29Z")
> [@](#): > > \*Originally posted by GOM \* > \*\* kinda makes ya go: hmmmmm. \*\* Kinda makes me go - _yaaaawwwwnnnnnnn_ [Previous page](https://boards.straightdope.com/t/can-nasa-be-trusted-to-tell-us-the-true-color-of-mars/146438.md?page=2) [Next page](https://boards.straightdope.com/t/can-nasa-be-trusted-to-tell-us-the-true-color-of-mars/146438.md?page=4)