Motivations August 31, 2010Posted by Simon in Uncategorized.
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It’s interesting to think about the motivations of the institutions involved in the ALH84001 controversy. To oversimplify, it’s NASA against the universities.
The NASA scientists seem to have the absolute backing of their organisation to continue their research – refining the evidence for fossilised bacteria in the meteorite and refuting the attacks of those who disagree.
Why is NASA so committed to the research, when nobody else seems to be supporting them? Off the top of my head, I can think of 3 possibilities:
- NASA is more objective than its critics, and will continue with the research until there is absolute proof one way or another about what’s in the meteorite.
- Continued speculation about life on Mars is good for NASA’s budget.
- The highest levels of NASA promoted this research from day 1, and don’t want to admit they got it wrong.
I don’t know if I’m going to be able to conclude which (if any) of these is the right answer, but I’m trying to understand people’s motivations when I’m analysing the controversy.
The current view August 30, 2010Posted by Simon in Uncategorized.
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What’s the current “accepted wisdom” on the Martian meteorite theory? I did a survey of some of the popular and scientific press to see what they’ve said recently, as opposed to when the controversy flared up in 1996. Here’s some samples:
In Australia’s Cosmos magazine, physicist and author Paul Davies said last year that
Bill Clinton faced the world’s media on the White House lawn and announced that NASA had evidence for life on Mars in the form of putative micro-fossils in a Martian meteorite found in Antarctica. Though few scientists today believe the marks really are fossilised microbes, the episode raised awareness of the possibility that fossil organisms could make the journey from Mars to Earth.
Somewhat surprisingly, the New York Times hasn’t mentioned the issue much recently; back in 2004, discussing some research that cast more doubt on the biological origins of the signals in ALH84001, they were critical, but not dismissive of NASA’a claim:
NASA scientists said in 1996 that there was nothing ordinary at all about the rock, ALH84001. It came from Mars, and, they said, showed signs that life once existed there. That contention was in part based on what the scientists said were tiny magnetite crystals found in the rock that were similar in size and shape to those produced by bacteria on Earth. The scientists suggested that the crystals were formed by bacteria that lived on Mars billions of years ago.
But since then, other research has undermined the original findings.
Now, a team from the California Institute of Technology, the Massachusetts Institute of Technology and a Japanese research institution has looked at the rock and cast more doubt.
So, they say, it will be difficult to prove definitively that the crystals are a sign of life.
In 2006, New Scientist ran an article called Top 10: Controversial pieces of evidence for extraterrestrial life, and ALH84001 was number 3:
NASA scientists controversially announced in 1996 that they had found what appeared to be fossilised microbes in a potato-shaped lump of Martian rock.
But since then much of the evidence has been challenged. Other experts have suggested that the particles of magnetite were not so similar to those found in bacteria after all, and that contaminants from Earth are the source of the organic molecules. A 2003 study also showed how crystals that resemble nanobacteria could be grown in the laboratory by chemical processes.
Again, it’s what they’re not saying (that the initial idea was wrong) that’s notable.
Looking through these and other writings, it’s clear that scientists are much more willing to dismiss the NASA claim for evidence of Martian bacteria than the press, who seem cautious about making definitive statements on the issue. Is this because the press is presenting a more objective, balanced view of things? Or is it because they can sell more magazines or newspapers by keeping the debate alive? Something for me to look into….
A sample size of 1 August 25, 2010Posted by Simon in Uncategorized.
Today’s class at UQ got me to thinking about how probabilities play a role in the ALH84001 meteorite controversy. One thing that stuck in my mind was that there’s only *one* meteorite that people are arguing about.
What if there were two (or more) Martian meteorites that showed signs that could be biological in origin? It seems to me that might swing the argument in favour of those who say there had been life on Mars – it wouldn’t clinch the argument, but I think it makes it stronger.
But what if we find more and more Martian meteorites and none of them show anything like the signs in ALH84001? Then it becomes much harder to argue the case for life on Mars.
So it’s worth reviewing what we already know about Martian meteorites other than ALH84001. Here’s a quick primer:
The Meteoritical Society has a database of all known meteorites discovered on the earth; there are nearly 40,000 confirmed findings, with 92 of them being classified as coming from Mars*. When you account for meteorites that were found close together and appear to have come from the same rock, the number of unique finds drops to 34. Northwest Africa (Morocco, Algeria, Libya) and Antarctica seem to be the hot places for finding the meteorites.
Even though there are 34 Martian meteorites, ALH84001 seems to be unique. One initial analysis of ALH84001 described it as “a new, and unusual SNC (Martian) meteorite”. It’s extreme age – estimated at 4.1 billion years – means that it would have formed when Mars had liquid water, which makes the biological arguments more interesting.
What struck me about the database of Martian meteorites was the year in which they were discovered – almost all of them were found in the last 10 years. This suggests that there will many more discoveries to come, and if more are found that are similar to ALH84001, then the probabilities at play in the Martian life controversy could shift one way or the other.
*How do we know that a meteorite came from Mars, and not somewhere else in the solar system? Chemical analysis of the rock and the gases trapped inside reveals almost identical results to studies of the rocks and atmosphere of Mars. On this point, at least, there doesn’t seem to be much controversy.
How to insult a scientist August 19, 2010Posted by Simon in Uncategorized.
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One thing that’s become clear as I read through articles related to the ALH84001 meteorite controversy is how personal and bitter some of the arguments were. Here’s a sample of some of my favourite quotes:
Jeffrey Bada, Scripps Institution of Oceanography – “This looks like stuff from Earth. It’s extremely dangerous to make these bold claims.”
Ralph Harvey, Case Western Reserve University – “To be brutally honest, nothing that’s been presented to me so far is compelling in any way, and everything that’s been presented can be explained in another way.”
John Bradley, MVA (a microanalysis company) – referring to the NASA group that made the initial claim –”I think it’s fair to say that there isn’t a meteoriticist on the face of the earth who believes them. In my mind, it’s finished. They are absolutely dead wrong on this one.”
Everett Gibson, NASA – referring to meteorite scientists who he says are trained to investigate high-temperature geological processes, not the low-temperature processes associated with life – “Suddenly they have a rock that has low-temperature processes in it, and it’s something different for them, and they may not have the tools or skills to work in this. ”
Malcolm Walter, Macquarie University – referring to some Australian research that supported the NASA claim – “I’ve had a quick look at their published article and it is nearly all about their observations in the modern environment rather than a comparison with Mars. When it comes to comparing with the Mars meteorite I don’t believe a word of it. They did some pretty nice work on modern bacteria and then got carried away with their own enthusiasm. These people are very skilled in the field of studying modern bacteria but are novices when it comes to thinking about life on another planet.”
Who said science was boring? In some later posts I’ll explore some ideas about why people got so worked up on both sides of the debate.
What was the original claim for life on Mars? August 15, 2010Posted by Simon in Uncategorized.
I thought it would be interesting to go back to the original 1996 paper that kicked off the whole controversy and see what it said. Here are some extracts:
“It is possible that all of the described features in ALH84001 can be explained by inorganic processes, but these explanations appear to require restricted conditions – for example, sulphate-reducing conditions in Antarctic ice sheets, which are not known to occur.”
“In examining the Martian meteorite ALH84001 we have found that the following evidence is compatible with the existence of past life on Mars:”
and the paper then proceeds to list 5 pieces of evidence that hint at possible life.
“None of these observations is in itself conclusive for the existence of past life. Although there are alternative explanations for each of these phenomena taken individually, when they are considered collectively, particularly in view of their spatial association, we conclude that they are evidence for primitive life on early Mars.”
All in all, it’s not what you would call a strong argument, and one that’s fairly easy to attack. Maybe this is the source of at least some of the controversy – people assume that the authors are saying “We found life on Mars” but what they really said was “We found some individual pieces of evidence that, when put together, are evidence for life on Mars”.
In my last post, I referred to David McKay speaking to a Stanford class in 2009 about ALH84001 – I’ve found it on YouTube here. At the 48:00 mark, he reiterates that any individual piece of evidence might be discredited, but the conclusion follows from the whole collection of evidence. You’ve got to give him credit for sticking to his story through 14 years of attacks on his argument!
The Mars media circus August 13, 2010Posted by Simon in Uncategorized.
There are some fascinating media aspects to this controversy. Most of what follows comes from Vincent Kiernan’s incredibly thorough article in the journal Public Understanding of Science, The Mars Meteorite: A case study in controls on dissemination of science news (the abstract is free, access via your university library for the full article).
Back in mid-July 1996, the journal Science had accepted David McKay’s paper with the hypothesis that ALH84001 had evidence of fossilised life from Mars. Rumours about a big Mars announcement from NASA had been circulating even prior to this, but it took the scientific press awhile to put all the pieces together. It wasn’t until the 5 August issue of Space News, a small industry trade paper, that a journalist went public with a (still speculative) story about the meteorite finding.
The rumours continued to grow and eventually NASA and Science were under pressure to confirm the stories prior to the paper’s publication in the 16 August issue of the journal.
Even the White House got involved – President Clinton was briefed on the story, which eventually led to a scandal. Dick Morris, one of President Clinton’s advisors, happened to brag to a call girl that he was one of only 7 people in the world that knew about life on another planet. After the meteorite story became public, she got in contact with a tabloid magazine, which published a story that led to Morris’ resignation.
Eventually Science and NASA released the paper early with no embargo, and NASA held its famous press conference on 7 August. Last night I watched David McKay give a presentation to class at Stanford (search for Astobiology and Space Exploration in iTunesU if you’re interested) and he described the press conference, and the fallout from it, like this:
…we announced our findings, in Washington, and indeed that was a terrible circus, with hundreds of cameras and lots of questions, and the head of NASA and a few sceptics, and I’m not sure we ever recovered from that. It was a big news event and it was clearly something that got into the media in a big way, and that was not really our intent, but that’s what happened. The point of this is that the press blew it up much more that what we had actually said in the paper; if you read the paper it was fairly conservative and the press is not used to grey – they like black and white areas, so that’s what happened.
Contempt for the scientific revolutionary? August 8, 2010Posted by Simon in Uncategorized.
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I’ve been reading through everything I can find about the Mars meteorite controversy (to keep things simple, from now on I’ll just refer to the meteorite as ALH84001, which is the meteorite’s ‘official’ name*). I’ll go into more detail later, but the brief version is that in 1996, David McKay from NASA announced that ALH84001 contained a number of signs that indicated bacterial life was once present in the rock. It didn’t take long for other scientists to start attacking the claims, and the dispute got very heated.
Obviously I’m not the first person to look into this story, and one source that looks interesting is Kathy Sawyer’s 2006 book “The Rock from Mars: A Detective Story on Two Planets”. American Scientist magazine reviewed the book here, and one thing that immediately caught my eye was this passage from the review, discussing the way the scientific community treated McKay and his research group:
What they had to endure is described, with surprising frankness, by one of their detractors, who is quoted in the chapter titled “At Daggers Drawn” as saying that the McKay group “felt that they were being mistreated when in fact they were being treated with the same contempt [as] . . . anybody that would try and shake up the current paradigm.” Apparently contempt is viewed as a perfectly normal and appropriate response to anyone who thinks outside the box.
I was surprised to see a scientist in the middle of a controversy so aware of his place in Kuhn’s theory!
*ALH for Allan Hills, the area of Antarctica where it was found; 84 for 1984 – the year it was discovered; and 001 because it was the first one discovered that year.
Here we go! August 4, 2010Posted by Simon in Uncategorized.
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Welcome to my new blog! I’m going to be looking at the controversy about whether there is evidence for life on Mars or not. The full story begins with late 18th and early 19th century astronomers who thought they saw canals on the planet, and includes some inconclusive experiments performed by the Viking landers in the mid 1970s, but I’m going to focus on more contemporary events.
Remember back to 1996, when NASA announced there were signs of bacterial life in a Martian meteorite? Here’s the original press release:
Since then NASA’s claim has been widely discredited, but some scientists still insist that the evidence is real. It’s an interesting dispute that has played out in the media as well as the academic journals. And the story keeps going, with this news coming out last week:
Hopefully that will generate some debate that I can look into as well.
Thanks for reading, and please leave me some comments or questions.