Talk:Mars/Archive 9

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Opposition and minimum distance time.

The statement that the times of opposition and closest approach differ by up to 8.5 days does not mean the gap between successive oppostions varies by 8.5 days. That varies by much more. Example: in 2037, Mars reached a minimum of 73.838 Gm on Novemeber 11.3332, and eight days later, on Nov 19.382,5 reached opposition with a distance of 74.74066 Gm. The statement says the gap can be as much as eight and a half days. Saros136 (talk) 03:52, 1 October 2010 (UTC)

Thank you Saros for pointing out my error. I misunderstood the article and thought my clear brief statement was equivalent to what the article was trying to state. I have since sought relevant information and correctly stated the relationship of successive oppositions with a reference in the article. If that can be improved upon I welcome it. --Fartherred (talk) 18:01, 2 October 2010 (UTC)
You're welcome. I doubt I could improve your edit. Saros136 (talk) 02:58, 3 October 2010 (UTC)

Opposition page

The opposition primer is referring to close approaches, not oppositions, in the bottom table. The wording is misleading, granted. Higher up they discuss the fact that close approaches do not occur at the same instant as an opposition, and in one table make it clear they refer to the approaches in the vicinity of the oppositions. Good, but some later numbers are referred to as the distance at oppositions. Inspection of the table shows that it is indeed the time of close approach. The Mars opposition of 2003 did not happen on the 27th. The other reference, that I deleted, only covers decades, not nearly enough the a sentence mentioning an approach distance that has not been reached for tens of thousands of years. I'm substituting the number for greatest close approaches, form Solex. Saros136 (talk) 22:01, 2 October 2010 (UTC)

Oh, by the way, my source for the far close approach distances was Solex. Saros136 (talk) 22:42, 2 October 2010 (UTC)
I've got more ideas on the subject and sentence. Stay tuned. Saros136 (talk) 22:02, 2 October 2010 (UTC)

Picture of Mars Caption

The caption under the picture of Mars says it's from the Hubble, but the pic info says it's a "Global mosaic of 102 Viking 1 Orbiter images" —Preceding unsigned comment added by (talk) 09:33, 12 October 2010 (UTC)

You are correct. Thanks for the catch.—RJH (talk) 15:08, 12 October 2010 (UTC)

Unverified statement

The following statement was tagged as unverified in the article, so I'm moving it here for cleanup.

In the eight century, the Persian astronomer, Yaqūb ibn Tāriq, attempted to estimate the distance between the Earth and Mars in his Az-Zīj al-Mahlul min as-Sindhind li-Darajat Daraja.

The source listed for this statement was:

Sachau, Eduard (2001). Alberuni's India: an account of the religion, philosophy, literature, geography, chronology, astronomy, customs, laws and astrology of India about A.D. 1030. Routledge. p. 68. ISBN 0415244986. 

It looks like a valid source, but it does not confirm the statement. I haven't found any other source that will confirm the statement either, so at this point it is looking like possible misinformation. What the source does say is that the author of the Vishnu-Purâna lists distances between the planets, but there is nothing about them being measured using astronomical instruments. Yaqūb ibn Tāriq was noted mainly for his translation of Indian astronomy texts.

If somebody can provide a reliable source, then we can move the statement back into the article. Thanks.—RJH (talk) 18:06, 9 November 2010 (UTC)


the first paragraph tells us this is a star with a lower metallicity then the sun, whence it is not supposed to easily form rocky planets, but also says it has a ten times more massive debris disk then the sun. i think that is kinda paradoxal, since my understanding is more debris actually promotes the formation of planets, so either the indicator of metallicity for rock is flawed (it surely seems so), and i think since secondary factors but the primary star play significant roles in the formation of debris disks it is the most logical,(the inference of planets for metallicity then being "spurious") or it remains completely unexplained that there is a relation between a lot of debris but still not a planet (wich seems illogical), i don't mind paradoxes much personally, they keep me thinking, but i wonder what it contributes to our understanding of star systems. (talk) 08:45, 7 February 2010 (UTC)

A debris disk isn't necessarily the same thing as a protoplanetary disk. A debris disk consisting of fine dust can decay over time, so the fact that Tau Ceti has a denser debris disk may only mean that its disk is much younger than the Sun's. Plus a debris disk doesn't contain much mass, so it may only require the collision of a couple of large asteroids, for example. I.e. it is random and subject to variation. Finally, the subject of a star being more likely to have planets when it has a higher metallicity is also a statistical quantity rather than an iron-clad rule. Thus there will be exceptions.—RJH (talk) 16:34, 7 February 2010 (UTC)

Proxima Centauri/Tau CETI

Someone showed me this, which might me of interest to the article. Don't know anything about anything though, and it's probably a hoax. —Preceding unsigned comment added by (talk) 09:48, 9 June 2010 (UTC)

Yes a hoax from a blog, and so unusable here. Extraordinary claims require extraordinary evidence.—RJH (talk) 20:57, 9 June 2010 (UTC)

Work needed

Hello everyone! This article currently appears near the top of the cleanup listing for featured articles, with six cleanup tags. Cleanup work needs to be completed on this article, or a featured article review may be in order. Please contact me on my talk page if you have any questions. Thank you! Dana boomer (talk) 17:51, 8 November 2010 (UTC)

Tags I have noticed:

  • Unlike Earth, Mars is now geologically and tectonically inactive
  • reactions between iron and the excess oxygen may be the reason Mars has much more[vague] iron in its crust and mantle than does the Earth
  • attempted to estimate the distance between the Earth and Mars in his (Az-Zīj al-Mahlul min as-Sindhind li-Darajat Daraja)

-- Kheider (talk) 18:51, 8 November 2010 (UTC)

I thought I had this article cleaned up at one point after adding a bunch of cites and making revisions, but still it remained on the cleanup list. Seems like articles remain there in perpetuity once they are listed. Am I the only one helping take care of this page?—RJH (talk) 18:57, 8 November 2010 (UTC)
I think you are the primary. I keep a closer eye on the "Orbit and rotation" and "Close approach" sections, but I have not followed the rover missions in the last ~12 months. I think due to the on going Rover missions/orbiters this page gets hit regularly with cn tags. Mars has 205 references, more than any planet. Even the Earth has only 176 references. -- Kheider (talk) 19:13, 8 November 2010 (UTC)
The cleanup listings have been switched to a new bot, so they will be updated more. Check out the link I gave above to the featured articles cleanup listing - the same bot also does the project listings. Dana boomer (talk) 17:15, 9 November 2010 (UTC)
I think that all of the issues have been dealt with, although the table hasn't updated itself yet. Thanks.—RJH (talk) 20:13, 11 November 2010 (UTC)
Update the section on life on mars. Article claims that amounts of methane and formaldehyde could have come from volcanic/geologic process's. Mars is volcanically and geologically dead. HerrSticks (talk) 02:21, 13 November 2010 (UTC)
Mars is not geologically dead or even areologically (if that would be the right word for the analogous study of Ares) dead. It never developed plate tectonics, but had other tectonic activity. It has no presently active volcanoes, but there is still heat flow from a hot core that might have molten regions. The article is correct in suggesting that volcanic, geologic or biologic processes causing the methane would be consistent with our present state of knowledge. It is a pity I cannot give a reference for that. --Fartherred (talk) 04:40, 13 November 2010 (UTC)
Yes. Neukum et al (2004) states that, "calderas on five major volcanoes on Mars have undergone ... phases of activity as young as two million years, suggesting that the volcanoes are potentially still active today".—RJH (talk) 20:03, 16 November 2010 (UTC)

I have a few comments to add to the first two bulleted tag items above. To say "Unlike Earth, Mars is now geologically and tectonically inactive" is imprecise and probably incorrect. First, what does "geologically" inactive mean? Mars has a lot of active geological processes today (e.g. mass wasting, wind erosion and deposition, etc.). Second, if the phrase is meant to mean no internal (volcanic, tectonic) processes are active, this would have to be based on seismology and heat flow data. Only one seismometer has operated on Mars (Viking 2), which did record a low-magnitude quake. Golombek et al. (1992) suggests that Mars remains seismically active at the present time. Mars is probably still volcanically active too, although at a very low rate. We currently have no heat-flow data, so it's unknown exactly how warm Mars' interior currently is or isn't.

As for the second item, my understanding is that the anlayses of Martian meteorites and models of Mars' bulk density suggest that its mantle is enriched in iron as iron oxide (FeO). Some theories hold that Mars accreted from two populations of plantesimals: One was rich in metallic iron, and the other rich in water. The two were able to chemically interact early in Mars' history (before all the iron sank to the core) to form FeO and hydrogen, with the hydrogen readily escaping into space. See Boyce, J. (2009) The Smithsonian Book of Mars, for a discussion of the topic for general readers, and Barlow, N. (2008). Mars: An Introduction to Its Interior, Surface and Atmosphere, for more details. Hope this adds to the discussion. Schaffman (talk) 23:14, 11 December 2010 (UTC)

Martian temperatures

The article says: "Martian surface temperatures vary from lows of about -87 °C during the polar winters to highs of up to -5 °C in summers."

But another source ( :: Focus Sections :: The Planet Mars) says: "While the average temperature on Mars is about 218 K (-55 °C, -67 F), Martian surface temperatures range widely from as little as 140 K (-133 °C, -207 F) at the winter pole to almost 300 K (27 °C, 80 F) on the dayside during summer" (I suppose this is in the equatorial areas).

Another interesting fact is this: "The meteorology mast on the lander has observed a rapid drop-off in temperatures just a few feet above the surface, and one detailed 24-hour measurement set revealed temperature flucuations of 30-40 degrees Fahrenheit in a matter of minutes." MARS PATHFINDER WINDS DOWN AFTER PHENOMENAL MISSION. But this was written in 1997, so new relevant information could have collected since then. Hipporoo (talk) 04:55, 5 December 2010 (UTC)

Mmm, I guess it depends on who you trust to give you the temperature information: the people who send spacecraft to Mars or some generic web site. It would be nice to use primary sources for that information though.—RJH (talk) 23:32, 6 December 2010 (UTC)

We've known for a long time that the temperature at the winter poles can drop to 140K, the condensation temperature of CO2 on Mars [Leighton, R.B.; Murray, B.C. (1966). Behavior of Carbon Dioxide and Other Volatiles on Mars. Science, 153(3732), 136–144.] This is about -133° C. The way the article is worded now: "...lows of about -87 °C during the polar winters.." is wrong and needs to be fixed.Schaffman (talk) 22:08, 11 December 2010 (UTC) 22:06, 11 December 2010 (UTC)

That "about -87 °C" (while still apparently wrong) looks like one of those over accurate approximations we get from sloppy conversions. I'll bet someone took the quite rough figure of "about -125 °F" and converted it to Celsius. The 7 on the end implies a precision that was never in the original figure. Gee I wish America would properly metricate, then all this confusion would go away. HiLo48 (talk) 22:32, 11 December 2010 (UTC)

Yep, we'd have had a successful Mars Climate Orbiter mission, too. Schaffman (talk) 00:00, 12 December 2010 (UTC)

is there life on mars

is there life on mars —Preceding unsigned comment added by (talk) 23:15, 6 December 2010 (UTC)

It's a definite maybe.—RJH (talk) 23:29, 6 December 2010 (UTC)
You are going to want to think along the lines of extremophiles. -- Kheider (talk) 23:39, 6 December 2010 (UTC)

Nobody knows. Schaffman (talk) 22:25, 11 December 2010 (UTC)

Phobos Lifespan

Hello everyone! The article states in relation to Phobos "In about 50 million years it will either crash into Mars’ surface or break up into a ring structure around the planet." This information was taken from By Bill Arnett; last updated: 2004 Nov 20. However on May 10th 2008 Dr. Bijay Kumar Sharma submitted an article about this subject. In the article he recalculates the descent of Phobos and found that Phobos has much less time left and will crash into Mars in 10.4 Million Years. He also states that Phobos will reach the Roche Limit in 7.6 Million Years, at that point Phobos will break apart into a Saturn-like ring. Information about Dr. Sharma's article can be found at: Here is a direct link to the article itself in PDF format: WNSwins (talk) 02:41, 13 December 2010 (UTC)

Dates of Martian time periods are off

The age of the Hesperian/Amazonian boundary given in the article (1.8 bya) is a lot younger than what is most commonly cited. Although the absolute age is very uncertain and could vary by a factor of 2, I've seen it usually given as somewhere between 3.2 and 2.0 bya. (See Hartmann and Neukum, 2001 and Hartmann, 2005.) A readily accessible discussion of this is in Hartmann, W.K. (2003) Traveller's Guide to Mars; Workman: New York, pp. 33-34. Schaffman (talk) 20:10, 18 December 2010 (UTC)

Surface pressure of atmosphere

Is the atmospheric pressure indicated representative of the mass of the atmosphere independent of gravitation, or is it as per definition of pascals, a measure of actual pressure exerted in the Martian gravity field? Lucy Skywalker (talk) 21:47, 2 January 2011 (UTC)

acidic or alkaline surface

In the first paragraph under the 'Life' section it is stated that the Martian surface is acidic. However in the third paragraph in the same section it is stated that the soil has a very alkaline pH. These appear to be contradictory statements. Can someone who knows the correct conditions of the surface/soil. please resolve this apparent conflict? --Ddraig2 (talk) 01:01, 4 January 2011 (UTC)

I presume the two statements in question are:
Soil: "...the Martian soil has a basic acidity of 8.3..."
Life: "...that the soil has a very alkaline pH and it contains magnesium, sodium, potassium and chloride."
Both of these statements are in full agreement. However, using the word 'acidity' could be confusing to some (and obviously is). Does changing that word to 'pH' clear things up? --Xession (talk) 20:16, 4 January 2011 (UTC)

Actually I was referring to the last sentence in the 1st paragraph: "....Martian surface would have been too salty and acidic to support terrestrial life". A pH of 8.3 is not acidic under anyone's definition. I would also comment that the statement 'basic acidity' is an oxymoron. I am a chemist and the use of the term 'acidity' as a synonym for 'pH' while popularly used is scientifically unsupportable. Something can be acidic, or basic, or neutral (Ddraig2).

Edit request from Nightdave, 18 January 2011

{{edit semi-protected}} NASA Mars resources:

Nightdave (talk) 20:47, 18 January 2011 (UTC)

Exactly what is your request? HiLo48 (talk) 21:47, 18 January 2011 (UTC)
I'll be happy to make the edit for you when you say what you want edited specifically. Inka888 23:17, 18 January 2011 (UTC)


Is there any area of this article that could be shunted off to a sub-article to trim its massive length? Serendipodous 09:31, 26 January 2011 (UTC)

The article is already sectioned off into numerous articles leaving just abroad overview of everything that is Mars in this article. Generally the length of an article is not an issue so long as the information is complete and doesn't repeat information continuously throughout. In the case of Mars there's an incredible amount of information and it warrants a long, thorough page. --Xession (talk) 14:26, 26 January 2011 (UTC)
There's a few steps that I think could be taken. To me, some of the Exploration section seems a little too detailed and could be better summarized. (For example, I think it only needs to say when a probe arrived at Mars; not when it was launched.) The "Future Missions" section could be moved to its own article and summarized in a couple of sentences. There are also a few paragraphs scattered throughout the article that seem to cover tactical details at an excessive level and could be better summarized. (Example: "Two photographs, taken six years apart...".) I also wonder whether we really need to know what spacecraft discovered specific tactical details on Mars? Thanks.—RJH (talk) 16:27, 26 January 2011 (UTC)
Yes, each probe has its own article for such dry details. Look for anything that has its own article and trim away... Abductive (reasoning) 23:46, 28 January 2011 (UTC)

Pressure at the bottom of Valles Marineris?

If I am reading the section correctly, the pressure of Mars' atmosphere changes more slowly with altitude than it does on Earth. So does anyone know what the pressure would be at the bottom of the deep sections of Valles Marineris, 7 km down. Maury Markowitz (talk) 22:27, 28 January 2011 (UTC)

Hellas Planitia is actually the lowest point on Mars at a little more than 7-kilometers deep. The article states that the pressure at the deepest point of the basin should be around 1,155 Pa (.17 psi) while the mean surface pressure of Mars is 636 Pa (0.09 psi). Valles Marineris should have a comparable pressure at the lowest depths. --Xession (talk) 22:45, 28 January 2011 (UTC)

Original units were clearer?

According to IUPAC recommendations (see IUPAC Green Book and also page 1387-1388 of, the units ppm, ppb and ppt should not be used. That's why I have replaced them. Also, I think that chemists as well as astronomers understand the meaning of the prefixes mu for 1E-6 and n for 1E-9. Please let's discuss this here and not start an edit war! RolfSander (talk) 22:52, 4 March 2011 (UTC)

Wikipedia has it's own standards. For scientific articles, this means using "the units employed in the current scientific literature on that topic". There are a large... okay, huge number of scientific journal articles about Mars that employ ppm.—RJH (talk) 23:32, 4 March 2011 (UTC)
I can see your point now, thanks for the link. I work in atmospheric chemistry. Publications in this field currently have a mix of the old "ppb" and the new "nmol/mol". Although "ppb" still occurs more often, there is a trend to the new notation. Thus, I think both would be consistent with the WP-MOS recommendation which says: "In scientific articles, use the units employed in the current scientific literature on that topic. This will usually be SI, but not always". However, I see another problem with the old units. The WP-MOS says: "Only in the rarest of instances should ambiguous units be used". I can see at least 3 ambiguities with the old units:
  • 1) "ppb" may either refer to mass fraction or mole fraction, which are quite different.
  • 2) The "b" in "ppb" stands for billion, which can either be 1E9 or 1E12, see Long and short scales.
  • 3) "ppt" is even worse: if may either refer to parts per trillion (1E-12) or to parts per thousand (1E-3).

RolfSander (talk) 00:53, 5 March 2011 (UTC)

I've asked for input from the members of the WikiProject Astronomical Object. If the consensus turns out to be to convert the units and if #1 is a problem, then I'm not sure a straight conversion of units would work. We would need to find appropriate sources with units in "nmol/mol".—RJH (talk) 18:19, 5 March 2011 (UTC)
My immediate reaction is to use ppm. If ppb is considered too ambiguous, fractions less than 1ppm can be expressed as eg. 4×10-2 ppm. I know that's weird, and contrary to the 'official' units, but astronomy is full of such things (e.g. wavelengths in angstroms, distances in parsecs etc). Besides, IUPAC is not the relevant body to make such recommendations; the IAU is. Notice that the NASA-produced File:Martian Methane Map.jpg uses parts per billion. Of course any such ppm usage should state whether it is by mass or by number. Modest Genius talk 18:35, 5 March 2011 (UTC)
If IAU is the relevant body for you, do you know if they have any recommendations regarding this question?RolfSander (talk) 18:57, 5 March 2011 (UTC)
On concentrations, I'm not aware of any. Their web page on units discusses SI units etc, but is of no use here because 1) that deals only with dimensional units, but concentration is dimensionless, 2) the page clearly states that some very common astronomical units (angstrom, micron etc) should not be used, which is clearly neither enforced nor supported by the community, and 3) the 'official' recommendations should serve to inform us, but not bind us - the WP policy states 'use the units employed in the current scientific literature', which is not necessarily what the standards bodies proclaim is the 'correct' unit. Modest Genius talk 01:41, 6 March 2011 (UTC)
You are right, using the recommended SI units is clearly neither enforced nor supported by the community. I have a hard time understanding why this is so. This is not nitpicking as some people may think. Refusing to use SI units can even destroy a spacecraft. Here on the Mars page readers probably know what I refer to. If not, take a look at the Mars Climate Orbiter. RolfSander (talk) 16:31, 6 March 2011 (UTC)
Yes I do. In the case of Wikipedia, much of the style guide was built through a process of consensus. In some instances there were presumably objections to blanket enforcement of the SI standard; specifically when certain fields have preferred non-SI unit conventions and particularly when the non-SU units are more convenient to use. (For example, using cgs for describing planetary density or Janskys in radio astronomy.) I think it is just going to take time to change over.—RJH (talk) 23:36, 6 March 2011 (UTC)
I'm well aware of MCO, and could get into a very detailed discussion about why certain units have or have not been adopted by practising scientists, and the costs and benefits those entail. But this is not a forum, and this tangential direction of discussion is not helping us reach a consensus as to which units of atmospheric concentration are best to use on wikipedia. Modest Genius talk 23:54, 6 March 2011 (UTC)
Ok, let me try to summarize the current status then: RolfSander prefers using SI units, Modest Genius and RJH don't. No consensus here. However, I hope we all agree with the WP-MOS which says: "Only in the rarest of instances should ambiguous units be used". Here is my suggestion for a consensus: We keep ppm and ppb but add the information to all occurences if this is a mass fraction (kg/kg) or a mole fraction (mol/mol). AFAICS, on the Mars page all numbers are mole fractions. RolfSander (talk) 20:43, 7 March 2011 (UTC)
Certainly, that seems sensible to me. Of course ppm / ppb should never be used without stating whether they're by mass or by number. Either a footnote or a simple 'mass fraction' in the prose would be fine. Modest Genius talk 21:13, 7 March 2011 (UTC)
Good, looks like we've found a consensus. I'd like to wait for a comment from RJH though. BTW: "...should never be used without stating whether they're by mass or by number..." They NEVER should but they ALWAYS are! RolfSander (talk) 22:11, 7 March 2011 (UTC)

──────────────────────────────────────────────────────────────────────────────────────────────────── I don't believe that this information is necessarily readily available. For example, the NASA Mars Fact Sheet provides abundances in ppm without specifying the type. I suspect the convention is to use whatever form is most readily measured spectroscopically, which I would presume is by number.—RJH (talk) 16:10, 8 March 2011 (UTC)

Interesting! Even you (although very familiar with the topic) have to admit that you don't know for sure what ppm means here. I cannot understand why you are opposed to using non-ambigous units at least in the cases where we do know what is meant. Anyway, I checked the CH4 value in the original paper by Formisano et al. They use the expression "ppbv". Assuming an ideal gas, this is equal to mole fraction. Thus I assume that the other numbers are also mole fractions. RolfSander (talk) 19:53, 8 March 2011 (UTC)
Right, ppm in the sense of "by volume" appears to be the common usage in the astronomical literature for planetary atmospheres. We're following what is available in the literature, which is easier to cite and is a Wikipedia standard.—RJH (talk) 21:10, 8 March 2011 (UTC)

Water-worn structures on Mars

The section about water-worn structures on Mars under Hydrology is muddled (as was the source material under Water on Mars, to be fair). The description of the outflow channels is OK, but IMO spends too long on reasoning against the water origin without also presenting the evidence for water origin. More pressingly though, as in the daughter article, there's a critical confusion here between the dendritic, Noachian, valley networks and the huge, single thread, Hesperian outflow channels. These are fundamentally different things, well recognised as such in the literature, and it is in fact the valley networks that present the more compelling evidence for a warm, wet early Mars (which is surely where this section should be headed). This is totally unclear as the article stands.

If no-one has any comments, I'll make a discreet rewrite of this section for clarity at some point in the near future. And given the FA status of the article, I promise not to muck it up. And also not to noticeably increase the length!

DanHobley (talk) 03:16, 31 March 2011 (UTC)

I'd say, WP:SOFIXIT applies here. As long as WP:NPOV is maintained, I don't think anybody is going to complain too much about an improvement to the article. Thank you. Regards, RJH (talk) 14:44, 31 March 2011 (UTC)

Epoch vs. Period in geologic history section

I know this will sound pedantic to some, but Noachian, Hesperian, and Amazonian are periods, not epochs. The epochs are subdivisions of the periods (e.g. early Noachian, middle Noachian, late Noachian, etc.). I think the article should comply with standard stratigraphic nomenclature. I can change this if no one objects. Schaffman (talk) 14:01, 18 April 2011 (UTC)

Unfortunately the scholarly literature is pretty inconsistent about this. There are more uses of "Nochain epoch" than there are of "Nochian period", for example. I think we should probably discuss it first.—RJH (talk) 16:32, 18 April 2011 (UTC)
You're right; the literature is inconsistent. I'm curious though where you got the "more uses of Noachian epoch than period..." from. I did a Google Scholar search and got the opposite result. There were nearly twice as many instances of Noachian period over Noachian epoch (193 vs. 100). The inconsistancy in the literature doesn't surprise me too much. Not all Mars researchers are familiar with stratigraphic principles, and journal editors don't always do their job well. Still, I'm curious to hear from others on the topic. You got me thinking that maybe the period/epoch convention is strictly a North American thing. If so, I stand corrected. Schaffman (talk) 19:57, 18 April 2011 (UTC)
You're correct, there are more instances of "Noachian Period"; I think I was doing some odd search combinations, which gave me the opposite result. I added a request for comment on the Astronomical Objects WikiProject.—RJH (talk) 20:10, 18 April 2011 (UTC)
I agree, it probably ought to be period. Though it's only just occurred to me that it would be far more sensible if it were eon, based on comparison to the lengths of divisions on Earth! But there you go, it's not. DanHobley (talk) 00:33, 19 April 2011 (UTC)
I think the reason the time length of periods on Mars is so large compared to Earth is due to inadequate resolution, absence of a fossil record to examine, and the less dynamic nature of Mars’ geologic history. The time periods are based on the stratigraphic relationships of rock units that can be mapped from space (or historically for the Moon, through telescopes). For better or worse, these mappable units are grouped into time-stratigraphic systems (for Mars: Noachian, Hesperian, Amazonian). The geologic time equivalent of system (at least in North America) is the period. On Earth, the time-stratigraphic equivalent of eon is eonothem, a term rarely used, and one certainly not in use when planetary geologic mapping began in the 1960s and 70s. Schaffman (talk) 13:48, 19 April 2011 (UTC)
It turns out the Geology of Mars article has been using 'Period' for some time. It would make sense to be consistent between the two and use 'Period' in this article as well. Thanks. Regards, RJH (talk) 20:19, 19 April 2011 (UTC)
As there was no further discussion, I implemented the agreed upon change of 'epoch' to 'period'. Thank you.—RJH (talk) 21:13, 25 April 2011 (UTC)

Degrees C and F, relative

In the Climate section it says that temperatures in the south varies by 30C (86F) more than they do in the north. This is wrong as it is a relative temperature not an absolute one 30C corresponds only to 54F. —Preceding unsigned comment added by (talk) 05:38, 27 April 2011 (UTC)

Good catch! Thanks. Regards, RJH (talk) 21:36, 27 April 2011 (UTC)

Planetary embryo (?)

"Hf-W-Th evidence for rapid growth of Mars and its status as a planetary embryo" by Dauphas and Pourmand: Mars allegedly is a "oligarch", a protoplanet, while Earth is some kind of later collision product. Rursus dixit. (mbork3!) 10:43, 31 May 2011 (UTC)

That's interesting, but it appears to be a preliminary result at this time. Regards, RJH (talk) 15:04, 3 June 2011 (UTC)

Edit request from, 2 June 2011

Please change

{{Vertical images list|align=right|image1=Karte Mars Schiaparelli MKL1888.png|image2=Lowell Mars channels.jpg|image3=Mars HST Mollweide map 1999.png|width=200px|caption1=Map of Mars by Giovanni Schiaparelli|caption2=Mars sketched as observed by Lowell sometime before 1914. (South top)|caption3=Map of Mars from [[Hubble Space Telescope]] as seen near the 1999 opposition. (North top)}}


{{multiple image|direction=vertical|width=200|image1=Karte Mars Schiaparelli MKL1888.png|image2=Lowell Mars channels.jpg|image3=Mars HST Mollweide map 1999.png|caption1=Map of Mars by Giovanni Schiaparelli|caption2=Mars sketched as observed by Lowell sometime before 1914. (South top)|caption3=Map of Mars from [[Hubble Space Telescope]] as seen near the 1999 opposition. (North top)}}

This rest of the article is using {{multiple image}} and this will make the caption font and image margins uniform throughout the article. Thank you. (talk) 22:32, 2 June 2011 (UTC)

Yes check.svg Done. Thanks! Samwb123T-C-E 02:20, 3 June 2011 (UTC)

Trimming images

I did some trimming of the images in this article because it was getting steadily bloated with new additions, which significantly impacts the article download time. There is already a Mars gallery on the commons. Regards, RJH (talk) 19:09, 6 June 2011 (UTC)

areoid vs "sea level"

A recent edit summary:

  • (added reference and mention to the ""areoid"" of Mars -- which is another term for its mean surface gravity, a measure analogous to zero sea level on Earth.)

On Earth, sea level may be the median altitude but it is not the mean altitude, and local gravity is not constant on the geoid (though potential energy ought to be). Nor is "sea level" on Mars defined as a mean of anything.

The geoid is defined as a surface perpendicular to local gravity, which on the oceans coincides with mean sea level. An areoid can be defined similarly, but I'm less sure that atmospheric pressure (which defines 'sea level' on Mars) would be constant on such a surface, and I'm confident that local gravity would not be. —Tamfang (talk) 04:26, 28 June 2011 (UTC)

Yes, I agree. Though the reference to sea level is probably the clearest way to describe what this is is a single sentence - and I think more detail would be inappropriate here. I've made some minor adjustments... feel free to change again. DanHobley (talk) 13:34, 1 July 2011 (UTC)

surface gravity

Equatorial surface gravity is given as 3.711 m/s² = 0.376 g; but 3.711/9.81 = 0.378. —Tamfang (talk) 03:50, 26 March 2011 (UTC)

Yes and I don't think we need three digits anyway. Most sources list it as 0.38.—RJH (talk) 17:17, 26 March 2011 (UTC)

What are the extremes (polar and equatorial)? —Tamfang (talk) 19:16, 26 March 2011 (UTC)

On Earth at least, the surface gravity at the equator is about 1/291 (=0.34%) less than at the Pole.[1] From the centripetal force article, F = mrω2. The ω is about the same for Earth and Mars, so the Force would be reduced by the ratio of the two planets radii (0.53). Assuming I got that right, then the percentage is slightly higher than on the Earth (0.53/0.38 = ×1.4).—RJH (talk)
Rotation isn't the only thing contributing to the difference. —Tamfang (talk) 23:37, 5 April 2011 (UTC)
Besides radius, what else are you suggesting?—RJH (talk) 15:02, 6 April 2011 (UTC)
What does 0.53/0.38 get you? —Tamfang (talk) 23:58, 6 April 2011 (UTC)
The radius is 0.53 Earth, while the gravity is 0.38 Earth. Thus the ratio of the centripetal force to the gravitational force is 1.4 times that of the Earth. 1.4 × 0.34% = 0.48%. So, for this back of the envelope calculation, the gravity at the equator is roughly 0.48% less than the gravity at the pole. That doesn't match your result below though, which shows a reduction of 1.63%. Shrug.—RJH (talk) 15:59, 7 April 2011 (UTC)

Using the given numbers for mass, equatorial and polar radius, and equatorial rotation speed, and applying the spherical approximation, I get polar gravity 3.7582 and equatorial gravity 3.6970 m/s²; but GM/R² is accurate only when the mass is spherically symmetric, and besides I don't know how much the Tharsis bulge affects the gravity. So I wish I knew where to look for better estimates of the gravity at the poles and at the top of Pavonis Mons. —Tamfang (talk) 23:58, 6 April 2011 (UTC)

I'm pretty sure these values are out there in the literature, but it's proving tricky to track down. I can tell you though that the gravitational anomaly at long wavelengths across the Tharsis bulge is about 0.5 Gal (i.e., 0.005ms^-2), and the anomaly associated with the specific volcanoes around that area is between 1 and 3 Gal (i.e., 0.01-0.03ms^-2, c. 1% of total gravity!) - see papers by Smith et al. (1999; Science) and McKenzie et al. (2002; EPSL). I suspect this huge bulge in the gravity field in one hemisphere is why you don't see the actual figures for g at the pole and "equator" quoted very often. Nevertheless, I'll try to find a paper that actually gives absolute values (probably in the Viking literature from the late 70s early 80s). And yes, I think you're right that there's more to the calculation than radius & rotational speed - the way to do it properly appears to require solving for the spherical harmonics, not just going for the spherical approximation. DanHobley (talk) 13:27, 7 April 2011 (UTC)

Infact,Mars can be lived on!It might have some water.It might or might not have oxegin.But that is ok.Because we can take care of that.The best way of getting oxegin is planting plants on it. — Preceding unsigned comment added by 137harnsberrya (talkcontribs) 00:28, 6 August 2011 (UTC)

Dan, the surface gravity at the pole is given as 3.758 m/s2 and 3.711 m/s2 at the equator in H.H. Kieffer et al. (1992) Mars; University of AZ Press, p. 29. This is based on the difference between equatorial and polar radius (GM/R2). Not sure how these numbers have changed with more recent geophysical data, but that's what's out there in the older literature. Schaffman (talk) 13:22, 18 April 2011 (UTC)
OK, I think I get this now. The spheroid (AKA, "geoid", "areoid"), which is the 1st harmonic spherical approximation - the one that lets the planet bulge out at the equator, but nothing else - gives values of 3.758 and 3.711 m/s2 at the pole and equator respectively. This is calculated purely in abstract, based on known bulk planetary density and geometry. However, more recent satellite observations of the actual magnetic field have shown that the volcanoes (and associated ?basaltic intrusions) really do affect local gravity at least a bit, with the amount of perturbation to the areoid you see depending on the scale you're looking at - as you would expect. The maps of the gravitational anomalies in the Smith and McKenzie papers are both describing deviations away from this (hypothetical) areoid. Hence, the answer to Tamfang's question is - it depends on the scale you look at. Tharsis gives a broad wavelength bulge of about 0.5 Gal, but with local anomalies corresponding to each volcano of between 1 and 3 Gal (= 0.01-0.03 m/s2, c. 1% of the total gravity, c. 25%-75% of the difference in average gravity between the pole and equator!). DanHobley (talk) 15:54, 29 April 2011 (UTC)
Of course, the assumption that gravity figures are constant over time, is not entirely correct. Cheers, Greenodd (talk) 23:37, 11 August 2011 (UTC)

Differences in the sources

Параметр English Wikipedia Allen's astrophysical
quantities, 2000:294-297 [1]
NASA [1] [2] NASA [2] [3] NASA [3] [4]
Semimajor axis of orbit 227,939,100 km
1.523 679 AU
227.93664×106 km
1.52366231 AU
227.92×106 km 227,943,824 km
1.523662 A.U.
Orbital period 1.8808 Julian years,
686.971 days
1.88071105 Julian years (Sideral) 686.980 days 1.8808476 Earth years,
686.98 Earth days
1.8808476 y
Synodic period 779.96 days 779.9361 days 779.94 days - -
Eccentricity 0.093315 0.09341233 0.0935 0.0933941 -
Inclination to ecliptic 1.850° to ecliptic 1.85061 (deg.) 1.850 (deg.) 1.85 degrees -
Longitude of ascending node 49.562° 49.57854 (deg.) - - -
Equatorial radius 3,396.2 ± 0.1 km 3397 km 3396.2 km - 3396.19 ±.1
Volume 0.151 Earths,
1.6318×1011 km³
0.149 Earths 0.151 Earths,
16.318×1010 km³
0.151 Earths,
1.63116×1011 km³
Mass 6.4185×1023 kg 0.64191×1027 g 0.64185×1024 kg 6.4169×1023 kg 0.641693±.000064 ×1024 kg
Density 3.9335 ± 0.0004 g/cm³ 3.94 g/cm³ 3933 kg/m³ 3.934 g/cm³ 3.9340±.0008 g/cm³
Equatorial surface gravity 3.711 m/s² 371 cm/s² 3.71 m/s² 3.71 m/s² 3.71 m/s²
Escape velocity 5.027 km/s 5.02 km/s 5.03 km/s 5.030×10³ m/s 5.03 km/s
Sideral rotation period 1.025 957 day 1.025 956 75 day / 1.025 956 754 3 days 24.6229 hrs 1.026 Earth days
24.623 hours
1.02595676 d
Axial tilt (Inclination equator to orbit, Obliquity to orbit) 25.19° 25.19 (deg.) 25.19 25.2 -
North pole right ascension 317.681 43° 317.681° 317.681 - 0.106T - -
North pole declination 52.886 50° 52.886° 52.887 - 0.061T - -
  1. ^
  2. ^ Williams, David R. Mars Fact Sheet. National Space Science Data Center. copy
  3. ^ Mars: Facts & Figures. NASA. copy
  4. ^ Planets and Pluto: Physical Characteristics копия
Well, the good news is that the values all seems to agree with each other in the first few digits. Allen is referencing the Explanatory Supplement to the Astronomical Almanac from 1992, which may be a little dated. Regards, RJH (talk) 17:39, 11 August 2011 (UTC)
It is bad practice to show in the article's card bad data from unknown source. Марсианский хро (talk) 12:28, 17 August 2011 (UTC)

Comparing orbital characteristics with referenced source

File:HORIZONS Mars data 2007 08 08.png - screenshot NASA's site on date 2007 08 08 for compare with card. Марсианский хро (talk) 17:02, 16 August 2011 (UTC)

Parameter English Wikipedia Source ( on 2007-Aug-08) Conclusion
Aphelion 249,209,300 km not in source [citation needed]
-"- 1.665 861 AU not in source [citation needed]
Perihelion 206,669,000 km not in source [citation needed]
-"- 1.381 497 AU not in source [citation needed]
Semi-major axis 227,939,100 km 3397+-4 [citation needed]
-"- 1.523 679 AU "1.523676824505276E+00" [citation needed]
Eccentricity 0.093 315 "9.331952575248627E-02" [citation needed]
Orbital period 686.971 days 686.98 d [citation needed]
-"- 1.8808 Julian years 1.88081578 y [citation needed]
-"- 668.5991 sols not in source [citation needed]
Synodic period 779.96 days not in source [citation needed]
-"- 2.135 Julian years not in source [citation needed]
Average orbital speed 24.077 km/s 24.1309 km/s [citation needed]
Mean anomaly 19.3564° "3.377586933117296E+01" [citation needed]
Inclination 1.850° to ecliptic "1.849069591375086E+00" [citation needed]
-"- 5.65° to Sun's equator not in source [citation needed]
-"- 1.67° to invariable plane[2] not in source (some digits lost) [citation needed]
Longitude of ascending node 49.562° "4.953665683803469E+01" [citation needed]
Argument of perihelion 286.537° "2.865833028032102E+02" [citation needed]
Satellites 2 not in source [citation needed]

Марсианский хро (talk) 12:24, 17 August 2011 (UTC)

Web citation does not work automatically

For the citation "Scientists Discover Concealed Glaciers on Mars at Mid-Latitudes" I can go to WayBackMachine and manually plug in and choose the 20th of May 2011 to get the Jackson School of Geosciences article, but just clicking on the link does not work. Is my software out of date or is the link broken? Fartherred (talk) 16:05, 4 December 2011 (UTC)

It seems to work for me, but takes a couple of seconds to load the proper page. Regards, RJH (talk) 18:04, 4 December 2011 (UTC)

Suggested minor change in headline: Timeline -> Timeline of Mars Missions

When reading the content, it is unclear weather 'Timeline' refers to the Timeline of Mars missions or the history of the planet. — Preceding unsigned comment added by (talk) 08:44, 8 December 2011 (UTC)

I agree with the suggested change but also would like to point out that there would be a repeat of the table Timeline of Mars exploration at the Exploration of Mars article. I think that this kind of table should appear only once in that article. Tom Paine (talk) 12:52, 10 January 2012 (UTC)
I'm slightly opposed to the proposed title. Is there any way it could be done without including the word "Mars"? --W. D. Graham (previously GW) 17:43, 10 January 2012 (UTC)
What about 'Timeline of Exploration Missions' or simply 'Timeline of Exploration Missions'? Anyway I still think this table should only appear in the Exploration of Mars article.Tom Paine (talk) 18:28, 11 January 2012 (UTC)
or "Timeline of Human Exploration" OlympusMoons (talk) 17:17, 20 January 2012 (UTC)

Well, the name of the article shouldn't be used in the section headings, so "Mars" can be removed. "Human" is assumed here, as Wikipedia is written by humans, for humans. That would reduced the list to "Timeline of missions" (or "Missions timeline"), "Timeline of exploration" (or "Exploration timeline"), or "Timeline of Exploration Missions". Regards, RJH (talk) 17:48, 20 January 2012 (UTC)

I like "Exploration timeline", but no strong opinion. DanHobley (talk) 03:11, 21 January 2012 (UTC)


WE Johns in one of his "Biggles" stories wrote in fair depth about a trip to Mars, using the disc shaped space ship "Space master".AT Kunene (talk) 10:07, 14 February 2012 (UTC)

That might be suitable material for the Mars in fiction article. Fartherred (talk) 02:41, 15 February 2012 (UTC)

Suggested minor change in headline: Timeline -> Timeline of Mars Missions

When reading the content, it is unclear weather 'Timeline' refers to the Timeline of Mars missions or the history of the planet. — Preceding unsigned comment added by (talk) 08:44, 8 December 2011 (UTC)

I agree with the suggested change but also would like to point out that there would be a repeat of the table Timeline of Mars exploration at the Exploration of Mars article. I think that this kind of table should appear only once in that article. Tom Paine (talk) 12:52, 10 January 2012 (UTC)
I'm slightly opposed to the proposed title. Is there any way it could be done without including the word "Mars"? --W. D. Graham (previously GW) 17:43, 10 January 2012 (UTC)
What about 'Timeline of Exploration Missions' or simply 'Timeline of Exploration Missions'? Anyway I still think this table should only appear in the Exploration of Mars article.Tom Paine (talk) 18:28, 11 January 2012 (UTC)
or "Timeline of Human Exploration" OlympusMoons (talk) 17:17, 20 January 2012 (UTC)

Well, the name of the article shouldn't be used in the section headings, so "Mars" can be removed. "Human" is assumed here, as Wikipedia is written by humans, for humans. That would reduced the list to "Timeline of missions" (or "Missions timeline"), "Timeline of exploration" (or "Exploration timeline"), or "Timeline of Exploration Missions". Regards, RJH (talk) 17:48, 20 January 2012 (UTC)

I like "Exploration timeline", but no strong opinion. DanHobley (talk) 03:11, 21 January 2012 (UTC)


WE Johns in one of his "Biggles" stories wrote in fair depth about a trip to Mars, using the disc shaped space ship "Space master".AT Kunene (talk) 10:07, 14 February 2012 (UTC)

That might be suitable material for the Mars in fiction article. Fartherred (talk) 02:41, 15 February 2012 (UTC)

map of mars

There didn't seem to be a map of Mars with features being names in the article - and I stumbled accross this image which looked like it might be useful to the article. EdwardLane (talk) 11:37, 20 February 2012 (UTC)

Niesten Mars globe segments.jpg
I added the image to History of Mars observation#Geographical period, since it is of historical interest. Thank you. Note that there are several modern maps available in the Geography of Mars article. Regards, RJH (talk) 17:06, 20 February 2012 (UTC)


This article states: "The first objects to successfully land on the surface were two Soviet probes: Mars 2[citation needed] on November 27 and Mars 3 on December 2, 1971, but both ceased communicating within seconds of landing." How were these successes? Sounds like they unsuccessfully landed as they failed within seconds. — Preceding unsigned comment added by (talk) 14:12, 23 February 2012 (UTC)

Wiki's own article on the Mars 2 probe states: "On November 27, 1971 due to on-board computer malfunction the lander entered the martian atmosphere incorrectly which resulted in crash-landing and loss of probe." Sounds like someone is being creative in their interpretation of the world "success." Mars 3 apparently did a little better - it got to the surface but failed within 15 seconds. Once again has to be pretty optimistic to call this a successful landing - it doesn't even meet the 30 second rule for dropped food items - see — Preceding unsigned comment added by (talk) 14:22, 23 February 2012 (UTC)
Suppose you brought your car to a stop at a red light, then the engine died. Was your stop unsuccessful? But I suppose we could just get rid of "successfully" and leave it to the judgment of the reader. Regards, RJH (talk) 15:31, 23 February 2012 (UTC)


Why is the synodic period given in Julian years, shouldn't this be in Gregorian years?AT Kunene (talk) 12:57, 4 March 2012 (UTC)

Probably because Julian year (astronomy) is a time interval used in astronomy. Regards, RJH (talk)

Minor typo

Under the section "Exploration missions", second paragraph, first sentence. "In the past" needs a comma after it. I know this is a bit trivial, but I had to spend a few moments figuring out what it meant and I figured I'd at least post this :)

"In the past dozens of spacecraft, including orbiters, landers, and rovers, have been sent to Mars..." to "In the past, dozens of spacecraft, including orbiters, landers, and rovers, have been sent to Mars..."

Yes check.svg Done--L1A1 FAL (talk) 13:22, 18 March 2012 (UTC)

Mars - Orbit and Rotation, Perihelion and Aphelion

In the Orbit and Rotation section, paragraph two, Mars is described as having had its last perihelion and aphelion both occurring in March of 2010.

Reference 117 cites a source that lists: Apr 21, 2009: Mars in Perihelion (1.38134 AU, 206.6 million km) Mar 31, 2010: Mars in Aphelion (1.66594 AU, 249.2 million km). — Preceding unsigned comment added by (talk) 17:58, 27 January 2012 (UTC)

Fixed by Kheider, thanks. Materialscientist (talk) 07:12, 29 January 2012 (UTC)

Does Mars have chaotically unstable rotation? this is from the "Earth" article, under the Moon section: "Some theorists think that without this stabilization against the torques applied by the Sun and planets to the Earth's equatorial bulge, the rotational axis might be chaotically unstable, exhibiting chaotic changes over millions of years, as appears to be the case for Mars.[149]" If true, it seems like it should be added here. H870rce (talk) 12:23, 26 March 2012 (UTC)

Re-analysis of 1976 Viking data, hints of life?

Life on Mars Found by NASA's Viking Mission?, National Geographic, Ker Than, April 13, 2012.

' . . On Earth this clock is set to a 24-hour cycle, but on Mars it would be about 24.7 hours—the length of a Martian day.

'In his previous work, Miller noticed that the LR experiment's radiation measurements varied with the time of day on Mars.

'"If you look closely, you could see that the [radioactive-gas measurement] was going up during the day and coming down at night. ... The oscillations had a period of 24.66 hours just about on the nose," Miller said. . '

We don't want to overstate this nor understate it. My goal is to summarize it in just straightforward fashion. FriendlyRiverOtter (talk) 19:19, 28 April 2012 (UTC)

Mars image badly cropped

Mars Valles Marineris.jpeg
Mars Valles Marineris EDIT.jpg
Mars Valles Marineris-Edit-MichaLR.jpg

The image directly at the beginning of the article is cropped *exactly* at the circumference of the planet... this doesn't look great and is unlike images in all other articles about planets.

Could someone add a little bit of black around it? — Preceding unsigned comment added by (talk) 00:59, 29 April 2012 (UTC)

Adding black rim is easy. I am actually worried by the triangular black cuts at the right bottom (which need explanation in the figure file) and pixelation at the rim, and would not pass it as a featured picture. This all can be "fixed" digitally, but this isn't an artwork. Any suggestions? Maybe an alternative image? Materialscientist (talk) 02:57, 29 April 2012 (UTC)
As it happens, we are not the first to ask these questions. Please comment, or I'll replace Mars Valles Marineris.jpeg with Mars Valles Marineris EDIT.jpg in a few days :-) Materialscientist (talk) 03:07, 29 April 2012 (UTC)
There's a version from Hubble on the Geology of Mars page, but the image isn't as good.DanHobley (talk) 03:20, 29 April 2012 (UTC)
I like the EDIT version, but isn't this cheating? I'm assuming the bites taken out at the bottom left are primary problems in the Viking data collection; smoothing them out feels a bit scientifically dirty... DanHobley (talk) 03:23, 29 April 2012 (UTC)
(Cheating) - not more than leaving the bites unexplained. Off course, notes should be added into all these files, at least on obvious artifacts (I'm sure there is a dozen of less obvious ones in there). Materialscientist (talk) 03:35, 29 April 2012 (UTC)

Climate and Life on red planet

You should mention in the article and Milutin Milanković. Sources Frozen Earth: The Once And Future Story of Ice Ages by Douglas Macdougall p.123 and [2]. Thanks.--Свифт (talk) 23:14, 11 May 2012 (UTC)

Hematite ≠ rust

So, seeing some edits that got reverted earlier today, I don't think we should be describing hematite as "rust". I'm pretty sure rust is implicitly the product of oxidation of metallic iron, and it certainly is not only hematite - there's a bunch of other iron oxides in there too. In contrast, most of the martian hematite is either going to be primary, or at most the oxidation of existing oxides like magnetite. No metallic iron involved.

Just wanted to make sure no-one had any objections to this before I change it. I know it's appealing to be able to describe the surface of Mars as rusty, and I'll try to preserve something like that, but the way it's written it factually wrong. DanHobley (talk) 02:30, 15 May 2012 (UTC)

Lead Image

I don't understand why a computer generated image based on radar data from Viking is used to show the planet in the lead image.
Why not use a true color image from Hubble Space Telescope?
The Hubble image has many more benefits:
  • informs the public to what Mars actually looks like while viewed from a distance
  • it shows the actual color of the areas of Mars: deserts, higher grounds, dust storm affected areas etc
  • it shows the polar caps
  • it shows the clouds in the atmosphere

— Preceding unsigned comment added by Scooter20 (talkcontribs)

Yes, both images look good. Since I don't think there is an actual policy that says the image in the lead must be true color, I think it's more a matter of consensus. To me the presence of significant cloud cover in the right-hand image is a little misleading because this is a fairly rare event. But otherwise I don't really care either way. The image at left looks more like how most people would see it through a telescope. Regards, RJH (talk) 17:20, 15 June 2012 (UTC)
Well I would not say that the Viking 1 radar image looks more like Mars seen through a telescope. I mean amateur telescopes cannot show enough detail of Mars to see more that a reddish point or disk. However if you would have a much more powerful telescope you would see the polar caps and possibly other features which makes it look more like the Hubble image.
I think that using the radar image is wrong because it misleads the public into thinking that Mars is a barren wasteland with no atmosphere or polar caps which is not the case.
In the same fashion, one could mislead people and show radar lead images of Venus and Titan, which are of course not appropriate since in reality you can't see any land features through their thick atmosphere.
I don't understand why we should brainwash people instead of educating them? Since when did Wikipedia become a propaganda tool?
Regards, Scooter20 (talk) 11:35, 17 June 2012 (UTC)
Guys, I think as a group here we're getting quite stressed out about a very minor issue. The Hubble image has the advantages that it presents a holistic, "as seen from Earth" (i.e., red) view of the planet at a single moment, and shows all the non-solid rock features you'd expect; CO2 caps, clouds, dust storms, etc etc. The Viking image has the advantage that it shows greater detail of the surface topography, including Valles Marineris, and presents a fundamentally higher resolution, i.e., it doesn't look fuzzy and is thus a "better quality image". Note that there is nothing deceitful or propaganda-like (Scooter20: please WP:FAITH; your comments actually irritated me quite a bit) about the Viking data. A quick look at visual imagery Google Mars will confirm that in the case of Mars, using daytime IR gives the same results as for visual imagery (IIRC, this will have been built out of the IR data because for Viking it was the only comprehensive data set for the whole planet). The coloration of Mars is its own kettle of fish (see, e.g., for a good discussion of the issues), but it looks to me like this image has been colorized to reflect the surface color as seen on the surface (i.e., rover-type view). As this is a technical surface image, the white CO2 caps have been deliberately excluded - i.e., it's summer at both poles in the Viking image. The residual, dusty water ice caps are much duller than both clouds and the seasonal CO2 caps (this is Austral winter from Hubble, by the looks of things). Clouds have also been removed in Viking (because it's radar), and I think a lot of the whiteness at the ?north pole from Hubble is actually clouds.
So, both images are fair representations of Mars. The choice is between showing a lower detail image that does include atmospheric and cryospheric features, versus a much higher detail image of the topography (and some of the most iconic topography on Mars, note), that doesn't. I'm undecided, but neither image is in any way inappropriate, as Scooter seems to be suggesting. Both should certainly be present in the article in some form, near the top ideally. DanHobley (talk) 15:33, 17 June 2012 (UTC)
UPDATE: I hadn't realized the hubble image proposed at the top of this discussion is actually less good than the 2005 one already present halfway down this article in the "Climate" section. 2005 was the Mars closest approach to Earth, and this image is much sharper (see right). You can also just about see Valles Marineris on the left side, and a dust storm as a bonus. If we're thinking about using a Hubble image, it maybe should be this one, not the one illustrated above. Note also that the poles are less prominent, and this is actually probably a more typical view. DanHobley (talk) 15:46, 17 June 2012 (UTC)
I think we should be consistent and use a true color image as lead and then the radar image can be shown in the topography section or whatever section is closer to that.
This is the case for other terrestrial bodies with atmospheres that are at least thick enough to be visible (eg: Earth, Venus, Titan, as opposed to Mercury, Moon etc).
Do you agree with replacing the Viking 1 radar topographic image as lead image with one of the Hubble images (maybe the second one, although I like the first one better because it shows more features)?
Regards Scooter20 (talk) 19:12, 17 June 2012 (UTC)

──────────────────────────────────────────────────────────────────────────────────────────────────── So many fine shots to choose from. This 1999 shot shows the polar cap, clouds, and Syrtis Major Planum. Shrug, I guess I don't care. It's the article text that matters. Regards, RJH (talk) 20:23, 17 June 2012 (UTC)

1999 image is nice, and on commons here File:Mars and Syrtis Major - GPN-2000-000923.jpg (Althought colored a bit more redish) Tom Ruen (talk) 20:54, 17 June 2012 (UTC)
Ok, I'm glad we can understand each other. I replaced the lead image with the Hubble image from 1999 and added the Viking 1 image (former lead image) to the Geology of Mars section.
Sorry about what I said about propaganda and brainwashing! I tend to get carried away sometimes.
Regards! Scooter20 (talk) 21:32, 17 June 2012 (UTC)
For "true color", I replaced the image from the 2005 release one, [3]. Tom Ruen (talk) 23:00, 17 June 2012 (UTC)
I like what you've done guys. That new image looks pretty nice! DanHobley (talk) 23:50, 17 June 2012 (UTC)

Equatorial Radius incorrect

The figure for the equatorial radius is 3.396.2 km or 0.533 Earths. This is incorrect. The figure of 0.533 Earths applies to the Equatorial Diameter, not the radius otherwise its diameter would be larger than that of Earth. — Preceding unsigned comment added by Zooto68 (talkcontribs) 17:19, 14 July 2012 (UTC)

Maybe I'm misunderstanding, but the radius is half the diameter. The diameter of the earth is 12,756 km. Half of this, the radius, is 6378 km. Dividing Mars' radius by Earth's radius gives 0.532, which is pretty much the figure given.
If you were to divide Mar's diameter by Earth's diameter, you'd get the same ratio. Naapple (Talk) 02:07, 3 August 2012 (UTC)

Settlement by 2060

Pete Worden predicts settlement on Mars by 2060

Mention in article — Preceding unsigned comment added by (talk) 14:17, 30 July 2012 (UTC)

Future missions

In this section the text «In 2016, the Russian and ESA plan to send rover...» should be changed to «In 2016, the Russian Space Agency and ESA plan to send rover...». (talk) 12:40, 3 August 2012 (UTC)

Thank you, fixed! Naapple (Talk) 22:14, 3 August 2012 (UTC)

Suggestion - transmission times and max distance

In light of the recent Curiosity landing, I came to this article looking for a discussion of Mars-Earth transmission times and couldn't find anything, so maybe someone more clueful than I can add it in. Also I couldn't find anything about the max distance between Mars and Earth (although I may have missed it). Thanks Manning (talk) 06:54, 6 August 2012 (UTC)

Funny that, we were attempting to do exactly the same thing, can the page be updated to include this information. We were attempting to calculate the response time of "curioisty" based on 2x tx delay plus any reaction time.Thanks. — Preceding unsigned comment added by (talk) 09:09, 6 August 2012 (UTC)

Edit request on 9 August 2012

One of the photographs, commons:File:Mars face.png is an altered photograph. The photo has been run through a pair of filters that have reduced finer detail to the point where it has been lost entirely. In fact, Jet Propulsion Labs has documented this alteration at

In the interest of scientific objectivity, I believe an unaltered photo would be more appropriate, and more in line with your own journalistic integrity. (talk) 19:09, 9 August 2012 (UTC)

The edits described in the JPL link you provide do not indicate that any valuable data has been lost or altered. They merely removed some of the noise and enhanced the contrast. If you look at the raw image, the details are the same, still no face, it is just low contrast and noisy. --Daniel 19:23, 9 August 2012 (UTC)
Not done: I do see some differences between the full-size versions, but it's unimportant because the article will only contain an undetailed thumbnail anyway. Since anyone who follows a link or two can easily see the unretouched image, I don't see a problem. Rivertorch (talk) 08:46, 12 August 2012 (UTC)

Cite errors in the article (at the end)

Cite error: <ref> tag with name "Metnet" defined in <references> is not used in prior text; see the help page. Cite error: <ref> tag with name "metnet_mission" defined in <references> is not used in prior text; see the help page. Cite error: <ref> tag with name "bbc_rincon061110" defined in <references> is not used in prior text; see the help page. Cite error: <ref> tag with name "nasa_maven" defined in <references> is not used in prior text; see the help page. Cite error: <ref> tag with name "usra4" defined in <references> is not used in prior text; see the help page. Cite error: <ref> tag with name "usra3" defined in <references> is not used in prior text; see the help page. Cite error: <ref> tag with name "nasa6" defined in <references> is not used in prior text; see the help page. Cite error: <ref> tag with name "nasa5" defined in <references> is not used in prior text; see the help page. Cite error: <ref> tag with name "missionpg" defined in <references> is not used in prior text; see the help page. Cite error: <ref> tag with name "day" defined in <references> is not used in prior text; see the help page. Cite error: <ref> tag with name "autogenerated1" defined in <references> is not used in prior text; see the help page. Cite error: <ref> tag with name "archive" defined in <references> is not used in prior text; see the help page. Cite error: <ref> tag with name "airspacemag" defined in <references> is not used in prior text; see the help page. — Preceding unsigned comment added by Kenorb (talkcontribs) 12:42, 10 August 2012 (UTC)

RE climate

Please update highest temperature on Mars. While the conservative figures quoted are from Nasa, there are other Nasa sites especialy rover site which quotes much higher numbers. Would somebody please further research and update. A quote from nasa rover source at :


During their exploration of Mars, the rovers have recorded temperatures ranging from midday highs of about 35 degrees C. (95 degrees F.) in spring and summer to nighttime lows of about minus 110 degrees C. (minus 166 degrees F.) in winter. Spirit has experienced greater temperature swings because its location is farther from the martian equator, where sunlight is seasonally either more direct or less direct than at Opportunity's location. — Preceding unsigned comment added by (talk) 20:56, 25 June 2012 (UTC)

Yes check.svg Done --Roentgenium111 (talk) 16:41, 10 August 2012 (UTC)

Summer temperatures in the Southern hemisphere are either 30 degrees Celsius warmer and 54 degrees Fahrenheit warmer than the equivalent summer temperatures in the north or they're 86 degrees Fahrenheit warmer and 48 degrees Celsius warmer than the equivalent summer temperatures in the north. Obviously, 30 degrees Celsius warmer can't equal 86 degrees Fahrenheit warmer as is wrongly claimed in the article. I can't access the MIT reference to check up myself which is correct, the Fahrenheit or Celsius value. — Preceding unsigned comment added by (talk) 22:35, 13 August 2012 (UTC)

I have fixed the value to conform with the reference. - Fartherred (talk) 00:25, 14 August 2012 (UTC)

The son of possessive case of Mars returns again, II

JorisvS changed Mars' to Mars's. This sort of thing was discussed in Talk:Mars/Archive 8#The possessive case of Mars both forms are used and the English language itself does not define the rules for possessive case spelling absolutely in this situation. Let us not get into establishing grammar for the language. I prefer WolfmanSF's spelling but would be satisfied to leave it as it is spelt. - Fartherred (talk) 19:30, 18 September 2012 (UTC)

Water on Mars!

"There is water on Mars." Double sharp (talk) 04:05, 30 September 2012 (UTC)

Croatian writer Giancarlo Kravar: Water on Mars! Discovered by NASA rover Curiosity. After a seven-week mission to Mars, Curiosity sent photos that reliably prove that on the planet used to bring water. Scientists estimate that the Curiosity even discovered a network of ancient riverbeds. Croatian daily Večernji list published a photo showing that the Martian surface once the river flowed. (talk) 03:12, 30 September 2012 (UTC)

Isn't this 15th or 20th time water (or past water) has been discovered on Mars? --Volcanopele (talk) 03:22, 30 September 2012 (UTC)
The Water on Mars article gives a large number of past findings of past water on Mars. Finding present water on Mars would be much more interesting. Double sharp (talk) 04:05, 30 September 2012 (UTC)

solar system of mars

what is the company name of mars? — Preceding unsigned comment added by (talk) 22:15, 12 October 2012 (UTC)

Mars, Incorporated of course. --RacerX11 Talk to meStalk me 22:25, 12 October 2012 (UTC)

Edit request on 18 October 2012

Mars was created by penguins in the early 1940s because of all the Eskimo raptors that hunted them. Too many penguin were dying because of the Eskimo raptors that the realized there has to be someplace new and safer. The penguins did what they could to fight off the Eskimo raptors while they thought of how to solve their problems. Many penguins were dying but the remaining survivors built a rocket made out of ice footballs. Barren2134 (talk) 05:35, 18 October 2012 (UTC)

X mark.svg Not done: Do you have any reliable sources to support this claim? Please note that many terrestrial observations have detected Mars before the early 1940s. Double sharp (talk) 05:47, 18 October 2012 (UTC)

Please Convert

All the atmospheric pressure data in the atmosphere section is given in kPA. Since this is an encyclopedia, we need English measurements so that it is meaningful and comprehensible to the layman. Someone needs to convert these pressures into PSI, ditto for the thicknesses of the ice sheets (need to be converted to feet/yards.) and add the standard customary figures to the metric ones. (talk) 04:38, 29 October 2012 (UTC)

The article as written meets the WP standard form for scientific articles. See WP:UNIT. DanHobley (talk) 13:24, 29 October 2012 (UTC)


This sentence has been around for a long time: "The summer temperatures in the south can reach up to 30 °C (54.0 °F) warmer than the equivalent summer temperatures in the north". I have tried to edit it but my edits are rejected. To be clear, 30 Celsius is 86 F. Not 54. The 54 is a typo. — Preceding unsigned comment added by Marleymanbob (talkcontribs) 16:48, 02 November 2012 (UTC)

Thirty degrees warmer isn't the same as just 30 degrees. The sentence isn't expressing a temperature but rather a temperature differential. Think about it this way: the difference between 0 degrees centrigrade and 30 degrees centigrade is 30 degrees. Convert those figures to Fahrenheit and you get 32 and 86—a difference of 54 degrees. Rivertorch (talk) 17:18, 2 November 2012 (UTC)
Converting a temperature difference on Mars to °F is inherently confusing and pointless. Why don't we just put it in K? Dicklyon (talk) 17:59, 2 November 2012 (UTC)
That occurred to me, too, but I suspect that most readers would need to go to kelvin for it to be meaningful to them. I suppose we might express the difference as 30 K and then put both 30° C and 54.0° F in parentheses. Rivertorch (talk) 18:52, 2 November 2012 (UTC)
Guys, bear in mind WP:UNITS. General policy says we should generally only be using standard scientific units. I'd say that's K. Fahrenheit definitely not needed in this context. DanHobley (talk) 19:48, 2 November 2012 (UTC)
Hmm . . . yes. It should have occurred to me that the MOS says something relevant about this. I was thinking in terms of providing content that readers like me with nonscientific backgrounds might be able to decipher without consulting a second article. There are other subject areas where my attitude would be Let 'em go to the other article and learn something new, and I suppose there's no reason to be inconsistent now that the shoe is on the other foot. By all means, let it be kelvins and kelvins alone. Rivertorch (talk) 23:04, 2 November 2012 (UTC)

Request for edit - temperature values are have incorrect conversions

The summer temperatures in the south can reach up to 30 °C (54.0 °F) warmer than the equivalent summer temperatures in the north.[134]

30°C is 86°F and 54°F is 12.2°C. I would guess that the 12.2°C/54°F is the correct value, but I cannot access the article referenced in the foot note Smoidel (talk) 16:32, 4 November 2012 (UTC) S Moidel 11-4-12

No, that's incorrect. Please read the preceding section. I believe the question has been resolved. Rivertorch (talk) 17:01, 4 November 2012 (UTC)
Yes Rivertorch, the statement is expessing a difference in temperature, which as also pointed out above is indeed confusing. So the coversion is correct, but on a side note, what about the statement itself? Can anyone confirm that there is that big of difference between the two hemispheres?--RacerX11 Talk to meStalk me 17:11, 4 November 2012 (UTC)
Confirm it how? Do we need another source? Rivertorch (talk) 17:22, 4 November 2012 (UTC)
Maybe I used the wrong wording. I may be just repeatedly overlooking it but where in Goodman source does it state the difference between the northern and southern summer highs? --RacerX11 Talk to meStalk me 17:49, 4 November 2012 (UTC)

Nevermind, just found it. sorry. --RacerX11 Talk to meStalk me 17:54, 4 November 2012 (UTC)

A subpage really should be linked for that ref. Sorry, I saw that the other day and had forgotten. It needs to be checked whether the other instance(s) that use the same refname are supported by the same or different pages. If they all refer to that page, then the citation url can simply be fixed. Otherwise, it would mean different refnames (i.e., different citations). If I have a spare moment I'll check it, but not today. Rivertorch (talk) 19:00, 4 November 2012 (UTC)


This fails to mention the hydrogen in the Martian interior. The December 1, 2012 issue of Earth and Planetary Science Letters will publish the finding of scientists Conel Alexander and Jianhua Wang, who studied Martian metorites. It is important that the Wiki page on the internal structure of Mars reflect that Earth and Mars formed from similar sources and that they have chondritic meteorites as their sources of water. — Preceding unsigned comment added by (talkcontribs) 4 December 2012

Not done for now: This is not an absolute "no" response to your request, but you need to provide the following:
  • The exact text you want placed into the article
  • If possible, an internet location where the proposed source can be found
If the subject of this edit is controversial, there also needs to be a consensus among multiple editors that the proposed edit is acceptable. —KuyaBriBriTalk 23:20, 4 December 2012 (UTC)

"Martian" vs. "martian"

The term "Martian" is (correctly) capitalized in most locations in the article, but the incorrect version "martian" appears. Please fix, thank you.

Fixed, thanks. Materialscientist (talk) 03:18, 16 December 2012 (UTC)

im the bestt n plutoo future — Preceding unsigned comment added by (talk) 17:18, 19 December 2012 (UTC)

Dead link

The ref with this url has a dead lnk: -- FutureTrillionaire (talk) 05:35, 8 January 2013 (UTC)

I can't find it. What ref is it currently (or what text does it follow)? Rivertorch (talk) 08:10, 8 January 2013 (UTC)
I found it, "Orbiter's Long Life Helps Scientists Track Changes on Mars", currently ref 22. This should be the updated link, but I find it rather vague to state that the southern ice cap "have been receding" based on a source which claims that CO2 deposites near the south pole was receding for a period of three years (which is now appr ten years ago). Njaelkies Lea (d) 11:11, 8 January 2013 (UTC)
Don't have refs to hand, but the gist of this is that a lot of the southern polar terrains have features (e.g., scarps, scallops, swiss cheese terrains) which are consistent with sustained loss of ices (can't recall whether CO2 or water - think water) from the southern polar region. They've documented changes using satellite repeat imagery too. It's thought this reflects gradual movement of ice from the south to the north poles, as I recall. On a year to year timescale, and looking at the actual CO2 cover, this is a bit more dubious though... as trying to argue for secular change on Earth from three photos of year-on-year snowlines would be. Refs to support the arguments from geomorphology can be found in the last few years of the NASA LPSC conference. I'll also see if I can find something more robust in Carr's Surface of Mars, I'm sure it's there. DanHobley (talk) 14:26, 8 January 2013 (UTC)
OK, on review, this sentence was actively misleading where it was. I hadn't realized it was up in the intro! I've just removed the whole sentence, along with the reference. I'll add a sentence or two somewhere lower down clarifying long term secular variations in ice cap cover, with decent reference. DanHobley (talk) 15:20, 8 January 2013 (UTC)
Sounds good! Njaelkies Lea (d) 15:36, 8 January 2013 (UTC)

What? No mention of evolution's co-discoverer Alfred Wallace's 1907 book-length debunking of Lowell's "canals"?

Nope. NO mention. I guess you could visit the Grand Canyon and rewrite his book about wasting time in the shower.

Though shovels are good better for dredging. — Preceding unsigned comment added by Garinwm (talkcontribs) 00:26, 1 August 2013 (UTC)

The title: Is Mars Habitable? Good details in our article on Wallace. -- (talk) 08:04, 12 March 2013 (UTC)

Olympus Mons

The main article, under the volcanoes section, says that Olympus Mons is the second highest volcano in the solar system, but the accompanying photograph has a caption saying it is the highest. Can we get a definitive clarification? Dezaxa (talk) 22:57, 15 April 2013 (UTC)

It's definitely the highest volcano. The only doubt can arise over whether it's the highest mountain. DanHobley (talk) 00:42, 1 August 2013 (UTC)

Mars Real moon names

If I'm not mistaken, Mars' moons have to do with Heaven's Family tree. Athena should be one of them. His son's names are Phobos and Deimos. Anyone knows the Mars moon Myth? Mars moon is a special kind of moon. It glows dim at night. — Preceding unsigned comment added by Garinwm (talkcontribs) 00:28, 1 August 2013 (UTC)

I'm confused what you mean. The moons are definitely Phobos and Deimos. DanHobley (talk) 00:45, 1 August 2013 (UTC)

Why use an ugly CGI image of Mars for the header?

All the other planets use true images be they composites of fly-bys or full images from the Hubble Space Telescope etc. Why should Mars be any different?

A true image is most definitely preferable to a computer generated image. That it is higher resolution is irrelevant is it is not a true image anyway. The current CGI image does not look good as part of the header and should be in the gallery sectionBaronVonchesto (talk) 04:46, 4 September 2013 (UTC)

That's not CGI - it's a mosaic of real imagery. A composite of a fly-by, as you put it. DanHobley (talk) 14:37, 4 September 2013 (UTC)


Swedish links to Universe, that's the wrong article. Can somebody remove it? — Preceding unsigned comment added by (talk) 04:02, 9 October 2013 (UTC)

Yes check.svg Done. — Reatlas (talk) 08:27, 9 October 2013 (UTC)

Semi-protected edit request on 10 January 2014

Iamjppunzalan (talk) 12:29, 10 January 2014 (UTC)

Note: No request was made. --ElHef (Meep?) 16:02, 10 January 2014 (UTC)

Distance from earth is missing

The distance between the earth and mars is not anywhere in the article. I think this information is very important for it to be omitted whatsoever. — Preceding unsigned comment added by Aleksandrvladimirov (talkcontribs) 22:38, 11 January 2014 (UTC)

Semi-protected edit request on 17 February 2014 (talk) 13:41, 17 February 2014 (UTC)

Voyager mosaic

This image should be free, and is amazing. Tell me if you want it uploaded so that it can be added to the article. [4], source here states NASA image:[5] CFCF (talk · contribs · email) 10:47, 20 February 2014 (UTC)

Thank you, but this image has already been uploaded here. The particular image does not exist in this article because there are a great variety of Mars images to choose from, but it can be found in the Valles Marineris article. Cadiomals (talk) 02:04, 21 February 2014 (UTC)

Header change?

Is there any possible way we can get this beautiful shot taken by Rosetta as the image in the infobox? Since it's not a NASA image, I'm not exactly sure of it's copyright, although it would make a fine replacement of the fugly mosaic, that really looks unrealistic perspective-wise, that currently takes the role. RazorEye ⡭ ₪ ·o' ⍦ ࿂ 09:05, 31 March 2014 (UTC)

Protected status preventing corrections

The article wrongly states that Marvin the Martian made his first appearance on television. He was in a short film shown in theaters before and between movies. Why is this article protected, anyway? — Preceding unsigned comment added by (talk) 03:38, 8 April 2014 (UTC)

Give some documentation and an editor will assist you; or better still, become an editor yourself. — Charles Edwin Shipp (talk)