Starting Friday April 5, many news media published articles about the detection of chlorophyll by spectroscopy applied to image data from the Pathfinder lander. Here are several of these announces, and my comments at the end of the page.
Friday, 5 April, 2002, 13:01 GMT 14:01 UK
By Dr David Whitehouse
BBC News Online science editor
Scientists have found "intriguing" new evidence that may indicate there is life on Mars.
An analysis of data obtained by the Pathfinder mission to the Red Planet in 1997 suggests there could be chlorophyll - the molecule used by plants and other organisms on Earth to extract energy from sunlight - in the soil close to the landing site.
Researchers stress their work is in a very preliminary state and they are far from making definite claims.
Even so, the work is attracting much attention in the scientific community and will come under intense scrutiny when it is presented to an astrobiology conference in the US next week.
This energy is used to drive photosynthesis, a process that converts carbon dioxide and water into the simple sugar glucose. Photosynthesis is the starting point for nearly all life on Earth. It is the great abundance of chlorophyll in leaves and other tissues that makes plants appear green.
Dr Carol Stoker, from the American space agency's (Nasa) Ames Research Center, confirmed the findings to BBC News Online but cautioned that they were "not ready for the big time".
Mars Pathfinder mission touched down in the Ares Vallis region of Mars in July 1997. It took many images of the surrounding area and released a small rover to sample rocks.
A detailed analysis of the images of the landing site now reveals two areas close to Pathfinder that have the spectral signature of chlorophyll.
According to experts it might be highly significant - or could be just a patch of coloured soil.
Dr Stoker's team scrutinised the so-called Superpan, which is a high-resolution, highly processed series of superimposed images produced by Pathfinder's camera.
It is a multispectral panorama of the landing site recorded in 15 regions of the spectrum, and contains a wealth of information about rock types, colours and textures.
Knowing the spectral signature of chlorophyll, the researchers wrote a computer program that systematically scanned the Superpan for any pixels of interest.
Specifically, the program looked for the spectral signature associated with red light absorption by chlorophyll.
Previous searches for evidence of chlorophyll in Pathfinder's pictures were carried out shortly after it landed.
Some tentative indications were seen but they were later dismissed as "possible image misregistration".
In Dr Stoker's study six regions of the Superpan matched positive for the chlorophyll signature.
For each of the regions, a full spectrum was plotted out and their exact position in the Superpan was then carefully examined.
All of the detections occurred close to the camera. This is to be expected say the researchers, as these are the areas where the camera has the highest sensitivity and resolution.
Close examination revealed that four of the cases occurred on the Pathfinder spacecraft itself. But two regions showed a chlorophyll signature in the soil around Pathfinder.
Given the controversial nature of their findings and the early stage of the research, the scientists want to hold back any claims about what they may have found until they have done more work and prepared a detailed paper for submission in a scientific journal.
Story originally published by Guardian, London / England, by Jamie Wilson, on April 6, 2002.
April 7, 2002
Posted April 5.02
American scientists have found "intriguing" evidence that may point to the existence of life on Mars.
The Nasa team analysed data obtained by the Pathfinder mission to the red planet which suggests there could be chlorophyll - the molecule used by plants on Earth to extract energy from sunlight - in the soil close to the landing site.
Carol Stoker, of the Ames research centre at Nasa, confirmed the findings to David Whitehouse, science editor at BBC News Online, but cautioned that the team was "not ready for the big time".
Despite the scientists' apparent reluctance to discuss the results, they have already begun to attract attention in the scientific community. The findings - which experts said might be highly significant or just a patch of coloured soil - are due to be made public next week at an astrobiology conference in the US.
The Pathfinder mission, which touched down in the Aes Vallis region of Mars in July 1997, took thousands of pictures of the landing area and released a small vehicle to collect rocks samples.
The Nasa team has looked at the so-called Superpan, a high-resolution, highly processed series of superimposed images produced by Pathfinder's camera, which was able to examine a range of spectral wavelengths.
The researchers wrote a computer program that looked for the spectral signature associated with red light absorption by chlorophyll.
Six regions of the Superpan matched positive for the chlorophyll signature. For each of the regions, a full spectrum was plotted out and the exact position in the Superpan was carefully examined.
All the detections occurred close to the camera - as would be expected because these were the areas where the camera had the highest sensitivity and resolution.
Close examination revealed that four of the cases occurred on the Pathfinder spacecraft itself, but two regions showed a chlorophyll signature in the soil around Pathfinder.
Previous searches for evidence of chlorophyll in Pathfinder's pictures were carried out shortly after it landed. The lead scientist of the Pathfinder imaging team, Peter Smith, who designed the Mars Pathfinder imaging camera, conducted a rudimentary search for chlorophyll on Mars with Justin Maki, a software designer.
Dr Smith and Dr Maki reported that some spots had a higher than normal infrared brightness under the rock Scoobee-do and a few other areas surrounding the Mars Pathfinder landing site, but later dismissed this finding as a "possible image misregistration".
Yesterday Colin Pillinger, the lead scientist on the British Beagle 2 mission to Mars that is due to be launched next year, said he did not know in detail how the research had been carried but would be surprised if the Nasa scientists had found chlorophyll. "It is a very unstable molecule, and I would be very surprised if it was surviving on the surface of Mars."
Mr Pillinger said his team would use a much lower level test in its efforts to find evidence of life on the red planet.
"We are going for the simplest test for finding life, that is, to find minerals deposited from water, which is carbonate, and then see if you can find associated with that mineral any organic matter that is part of a living organism," he said.
Let us hope that Colin Pillinger keeps up to date with all the recent findings, as he indicates that he knows no detail of the chlorophyll story (it is the third time that chlorophyll findings on Mars are published, after all). As chief scientist for the future Beagle lander to Mars, he decides what experiments will be carried out.
April 7, 2002
Two researchers of NASA Ames Research Center, Carole Stoker and Pascal Ashwanden, claim to have highlighted the presence of chlorophyll at the surface of the planet Mars from photographs taken by the Mars Pathfinder probe in 1997. They used a new computer algorithm to detect, by spectographic examination, the presence of biomarkers in the vicinity of the probe.
The image known under the name of "Superpan" is a 360° panorama obtained by the Pathfinder Mars camera from the Martian surface. It was acquired in 15 wavelengths of the spectral range 440 – 1100 mn and has an excellent definition.
The research team carried out an automated research on this document, to highlight the spectral signature associated with chlorophyl. The various parts of the image were initially calibrated in order to completely eliminate any parasitic chromatic variation. A meticulous examination, pixel by pixel, was then performed by a computer following three wavelengths (530 Nm, 670 Nm, 980 Nm), studying the continuity of the spectrum at 530 towards 670 Nm and 980 towards 670 Nm. The irregularities in the progression then appear as absorption lines in the luminous spectrum, from which it is relatively easy to extract the signature of a known substance, such as chlorophyll.
This absorption line was detected in six distinct places from Superpan. All appear where the resolution of the image is the highest. Four even occur on the spaceship and appear to be in connection with its own structure, while the others two are on the Martian soil, in small limited areas in the immediate vicinity of Mars Pathfinder.
However, a spokesman of NASA makes a point of moderating the information and claims that if the results are interesting, still nothing was scientifically proven.
Carole Stoker and Pascal Ashwanden will officially present the results of their research during the second conference of astrobiology, which will proceed from April 7 to April 11 at NASA's Ames Research Center, Moffett Field, California.
Jean Etienne
The green plains of Mars? Somebody is dreaming too much in here. Also, if the traces are on the lander, then they do not just "appear" to be in connection with the lander, they simply are. Nevertheless, one appreciates the date and location indicated for the forthcoming presentation of Carole Stoker and Pascal Ashwanden's work.
By Robert Roy Britt, Senior Science Writer
posted: 04:30 pm ET, 05 April 2002
A story published by the BBC today reported that NASA researchers "have found 'intriguing' new evidence that may indicate there is life on Mars," but a NASA spokesperson told SPACE.com that the claim is overstated.
The article, posted on the BBC's Web site, said researcher Carol Stoker, from NASA's Ames Research Center, worked with a team that used photos from the 1997 Mars Pathfinder mission to determine that there could be chlorophyll on Mars. The molecule is used by plants to produce energy from sunlight and would be considered a monumental find on the Red Planet.
A NASA spokesperson said, however, that Stoker's study involved a test of a new computer algorithm designed to search images for signs of biomarkers like chlorophyll. The ongoing tests have generated some interesting results, the spokesperson said, but nothing firm.
"Stoker has said they did not find evidence of chlorophyll or any evidence of life on Mars," the spokesperson said. "There's really nothing to report. I think they [the BBC] read more into the abstract than is really there."
An abstract of the study has already been made available on the Web. Scientists typically make such summaries of scientific papers available for other scientists to peruse. Journalists and the public can often access the documents. Yet when research yields groundbreaking discoveries, abstracts are often not made available in this fashion until a grand announcement has been made.
NASA in particular is known for keeping important discoveries quiet and announcing the findings to the entire public at once.
The BBC story said Stoker was scheduled to present her findings next week at an astrobiology meeting.
The NASA spokesperson said Stoker was not taking calls from reporters.
The abstract, reviewed by SPACE.com, discusses the study in technical terms and makes no extraordinary claims. After an automated search of images, in which signs of chlorophyll were sought, six images were studied further. Of those, four cases appeared to involve the spacecraft itself, according to the abstract.
"Two intriguing cases occur in small areas on the ground near the spacecraft," the researchers stated.
The ever skeptic space.com adds the voice of reason in the mediatic fuss. Nevertheless, many while smile at the idea of a transparent NASA. Also, it would have been appreciated that we get to learn the name of the alleged NASA spokesperson. (Speaking of lack of transparency...)
There is strictly no official NASA press release whatsoever related to the above topic as of May 7, 2002.
NASA Press releases are on: http://www.nasa.gov/releases/2002/index.html or in your email mailbox if you subscribed.
There are many, many evidence that there is life on Mars (See my Mars pages). However, the above announcements seem rather premature.
Strong comments would also be premature at this time. There is no need to rush; let's simply wait a few days and look at the turn of events. After all, the computer program used for the research was under test; any scientifically oriented mind would assume that the results cannot be considered necessarily correct at this time.
Strangely, when a Russian scientist working among the Hubble space telescope team announced that he detected chlorophyll and carotene like substances on the surface of Mars using spectrophotography data from Hubble, nobody reported it except www.marsdaily.com. There was no comment at all from NASA either. Nobody cared, yet the methodology was probably better.
