Disclaimers:

1) I am NOT an expert on this topic.

2) I will not quote the text of the articles-for copyright reasons, I will only summarize the data and conclusions.

3) As such, you have no way of knowing if I am mis-stating the works in question, unless you read the articles yourself. Take what I say with a grain of salt. I will try to keep my opinions in italics.



First, I will look at a brief summary of the most recent work, by Gary Huss, that appears on page 751 of the April 6 issue of Nature- this is Not the paper by Dr. Ireland but an analysis of their work... Dr. Ireland's paper is on page 776 in the same issue.

First, what none of the popular press articles- that I have seen- bothered to mention, is that the data in this field is NOT in agreement.

Dr Ireland reports that he found a depletion of 16O (relative to the heavier isotopes 17O and 18O ) in Iron particles collected from lunar regolith returned from the moon.

What the popular media (that I have seen) has not explained is that another study, Hashizume, K. & Chaussidon, M.- Nature 434,619–622 (2005) came to the opposite conclusion. Their studies indicated that the 16O was actually enriched. Both studies analyzed iron particles because particles of other minerals would likely contain oxygen incorporated into them during the formation of the solar system. Since the goal of the studies was to study solely the contribution of the solar wind, iron particles were chosen. I am not sure why it can be assumed that primordial iron can be assumed free of primordial oxygen- but since this fact seems to be well accepted I will accept it, but it does puzzle me...I assume there is empirical data to support this, such as sampling from deep within a nickel Iron meteorite.

Lunar regolith is considered an excellent way to study the composition of the solar wind since the moon has no atmosphere and has no shielding magnetic field. However, this first article claims that the Hashizume, K. & Chaussidon, M. work used particles that were last exposed to the solar wind between 1-2 billion years ago, While Dr. Ireland's sample was apparently exposed more recently. I wondered about this, 'what if the moon did have a magnetic field 1-2 billion years ago?' (Maybe Nick can answer this)... that would possibly lead to a difference in the ratios if the older sample was from a time when there was a lunar magnetic field, and Dr Ireland's sample was from a time without a magnetic field. However, upon thinking about it, it seems to me that, if this were the case, the 'older' sample would be the one depleted in 16O, since a magnetic field would deflect lighter isotopes more than heavier ones- this is the opposite of what the data shows...

The review article states that the work of Hashizume, K. & Chaussidon, M. used particles with a rather thick oxide layer, I presume due to oxidation on Earth? but their data was from deep within the particles. The oxide layer on Dr. Ireland's work was apparently thinner. Apparently, since they had to look deeper into their sample the work of Hashizume, K. & Chaussidon, M. was selecting for higher energy particles than that of Dr Ireland.why this should make a difference to the ratios I dont know...

This article by Gary Huss comes to the conclusion that the work of both groups was rigorous, and their contradiction is a mystery - perhaps one that the Genesis mission's results can help answer- if the data wasnt compromised by its crash.

What is clear is that it is WAY too early to be rewriting the theory of solar system formation based on these conflicting results

It was a good article that I am not doing justice to, and I am not covering all the points it mentioned... I will maybe say more when I have time.