Talk:Martian meteorite

message: Is there any source for this paragraph?
"It should be pointed out, however, that the isotope ratios do not actually match Mars ratios especially well, to the extent that Mars ratios are known..."
And this:
"Although common wisdom is that the SNC meteorites are from Mars, the Mars origin theory does have some problems. The isotope ratios are not an especially good match. A widely published graph showing a near-perfect match is alleged to be constructed from examples selected to "prove" the hypothesis and to be a poor representation of the real data. For example, the Ar40/Ar36 ratio for one meteorite (1650) is almost exactly half-way between Earth (300) and Mars (3000). Carbon dioxide, the predominant gas in the current Mars atmosphere, is unaccountably rare in the trapped gases in the SNC meteorites. The SNC meteorites do not show shock artifacts that would be expected in small objects ejected with enough velocity to escape Mars. The majority of SNC meteorites are quite young by geologic standards and seem to imply that volcanic activity was present on Mars only a few hundred million years ago. Cosmic ray traces in the meteorites indicate relatively short stays (3 to 3.5 million years) in space. It is asserted that there are no large young craters on Mars that are candidates as sources for the SNC meteorites."
Searches of the web found nothing close, except a couple of references to recent volcanic activity.  The paragraph also includes weasel terms "is alleged to be" and "it is asserted that" with no sources as to who is alleging or asserting.  Ken Arromdee 20:20, 13 September 2005 (UTC)
replies: text: In the absence of references, I've deleted this material. Ken Arromdee 21:53, 25 January 2006 (UTC)
thread_title: Untitled Comment 2 

message: In the article ALH84001 is described as a shergottite, but I don't know of anyone in the planetary science community who would classify it that way.  McSween and Treiman [1998] says, "this meteorite does not fit into any of the previously established SNC categories."  It should probably be its own category.--Will.i.am 21:52, 19 September 2006 (UTC)
thread_title:  ALH84001 

message: It is not clear to me how this is determined. Could they possibly be from another planet, moon, or other body? Also, has any meteorite from Venus, Mercury, or the moons of Jupiter ever been found? --Eraticus 04:20, 21 April 2007 (UTC)
thread_title:  Determination that Meteorite is from Mars 

message: Although there are a few prominent NASA websites that call these objects Mars meteorites, e.g., http://www2.jpl.nasa.gov/snc/ and http://curator.jsc.nasa.gov/antmet/mmc/, the overwhelming usage among scientists is martian meteorites.  In the NASA ADS bibliographic website, there are 26 publications listed that use the former term in the title and 636 publications that use the latter.  In light of this, there is little doubt about the preferred term, so this page should be renamed.  Unless there are reasonable objections that I can't think of, I will rename it. JeffG (talk) 01:21, 7 April 2010 (UTC)
thread_title:  Page needs renaming 

message: There is now about 110 specimens according to this article: Meteorite From Mars is Water-Rich. Danrok (talk) 21:06, 3 January 2013 (UTC)
replies: text: The reference given for the 99 number is now showing 114.  Perhaps we should update this number (and date), and expect to have to do this again in a few years. Watchwolf49z (talk) 00:37, 9 January 2013 (UTC)
replies: text: Done - Would someone please review the edit, I made a few changes to the prose that should be looked at. That dataBase gives the 61,000 number as well. This is really one of the best articles I come across in a while, especially concerning HIGHLY controversial subject material.  Well done !!! Watchwolf49z (talk) 15:01, 12 January 2013 (UTC)
thread_title:  Number of specimens 

message: This section states the following, "Then in 1983, various trapped gases were reported in impact-formed glass of the EET79001 shergottite, gases which closely resembled those in the martian atmosphere as analyzed by Viking.[6] These trapped gases provided direct evidence for a martian origin."
The last sentence that the trapped gasses provide direct evidence is not true since it cannot be proven merely from the resemblence to the current Martian atmosphere that they (the trapped gasses) actually came from it; especially from an object with an undetermined time of origin.  (The article goes on to give speculations about when shergottites were actually formed.)  It seems to me that you cannot obtain facts from speculations, no matter how reasonable they might be.  This is not to say the meteorites could not have come from Mars, or even that it is unlikely that they have.  But, based on what is written in this article, there is still no direct evidence.
Skinnerd (talk) 15:59, 8 January 2013 (UTC)
replies: text: That statement threw a red flag for me too.  However, after finishing the article I found it made sense.  These trapped gases are direct evidence, but not direct proof.  I don't think the article is stating this as fact above what is well referenced and notable. Science should certainly be investigating alternative speculations, just that it's not our job as encyclopedia editors. Watchwolf49z (talk) 00:08, 9 January 2013 (UTC)

text: The key is the referenced paper. Does the 1983 Science article by Bogard and Johnson support the statement given in the article. We can only go by what the references provide, and not add our own speculations. Read the sources - if the sources support the article content, then all is good. If you disagree with the sources - then go argue with them elsewhere, or find other reliable sources which disagree. Vsmith (talk) 22:30, 9 January 2013 (UTC)

text: Further, does the reference support the "direct evidence.." bit that follows? That could possibly be problematic, but we need to go to the reference to see. Vsmith (talk) 22:37, 9 January 2013 (UTC)

text: OK - I don't have acces to the 83 Science article, but "direct evidence of a martian origin came with the discovery of trapped atmospheric gases in one meteorite." quote from Combining meteorites and missions to explore Mars, by Timothy J. McCoy, et. al., PNAS, vol. 108 no. 48 . So the article text is valid - just might need to add the PNAS source as a reference for the line. Vsmith (talk) 23:18, 9 January 2013 (UTC)
thread_title: Comment on the History Section

message: I came here looking for this information and didn't find anything, so added a table based on a 2006 book about meteorite exposure ages which has a section on Martian meteorites. It's obviously just a starting point and needs to be updated with the most recent research.
Since they all originate apparently from only a few distinct impact events, I feel that it shouldn't be too much overload to the article to have a complete table of all the exposure ages determined so far. Robert Walker (talk) 09:41, 14 July 2013 (UTC)
thread_title: New section on cosmic radiation exposure ages

message: Can it be a volcanic object project with a velocy superior to the escape velocity.
If no. What else?  — Preceding unsigned comment added by 87.231.74.157 (talk) 12:59, 17 October 2013 (UTC)
replies: text: Yes. I would like to know the escape velocity to go from Mars to Earth. --Error (talk) 00:58, 30 July 2018 (UTC)
thread_title:  how a martian meteorite can have escaped the martian gravity field? 

message: News article says it is 4.4 billion years old: http://edition.cnn.com/2013/11/20/tech/innovation/mars-meteorite/  — Preceding unsigned comment added by 141.135.9.205 (talk) 12:03, 22 November 2013 (UTC)
thread_title:  Black Beauty, the oldest known Martian meteorite is older than 2.1 billion years