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[Chicago Astronomer - Astro Joe]

Did Viking provide evidence of life on Mars in 1976?...

In a Newscientist.com's article, it states that the Viking Landers found strong evidence of life processes on the surface...

The entire article here:

Viking's Methane

JULY 20, 1976. Gilbert Levin is on the edge of his seat. Millions of kilometres away on Mars, the Viking landers have scooped up some soil and mixed it with carbon-14-labelled nutrients. The mission's scientists have all agreed that if Levin's instruments on board the landers detect emissions of carbon-14-containing methane from the soil, then there must be life on Mars.

Viking reports a positive result. Something is ingesting the nutrients, metabolising them, and then belching out gas laced with carbon-14.

So why no party?
Because another instrument, designed to identify organic molecules considered essential signs of life, found nothing. Almost all the mission scientists erred on the side of caution and declared Viking's discovery a false positive. But was it?

The arguments continue to rage, but results from NASA's latest rovers show that the surface of Mars was almost certainly wet in the past and therefore hospitable to life. And there is plenty more evidence where that came from, Levin says. "Every mission to Mars has produced evidence supporting my conclusion. None has contradicted it."

Levin stands by his claim, and he is no longer alone. Joe Miller, a cell biologist at the University of Southern California in Los Angeles, has re-analysed the data and he thinks that the emissions show evidence of a circadian cycle. That is highly suggestive of life.

Levin is petitioning ESA and NASA to fly a modified version of his mission to look for "chiral" molecules. These come in left or right-handed versions: they are mirror images of each other. While biological processes tend to produce molecules that favour one chirality over the other, non-living processes create left and right-handed versions in equal numbers. If a future mission to Mars were to find that Martian "metabolism" also prefers one chiral form of a molecule to the other, that would be the best indication yet of life on Mars.

Link to New Scientist here: www.newscientist.com/channel/space/mg18524911.600

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It is part of "13 things that don't make sense" piece. There are excellent topics there for continued discussion here, such as what is pulling the Pioneers and Kuiper Cliff void.

Hmmm....

[Maddad]

Chicago said:

Joe Miller, a cell biologist at the University of Southern California in Los Angeles, has re-analysed the data and he thinks that the emissions show evidence of a circadian cycle. That is highly suggestive of life.

This circadian cycle, the cyclic increase and decrease in biological activity during a day, is forty minutes longer than circadian cycles on Earth. The Martian day is also forty minutes longer than an Earth day. I remember the tremendous excitement this created thirty years ago nearly. It seemed like slam-dunk evidence for life.

Eventually though some scientist objected that we couldn't be sure some non-organic process wasn't releasing this gas. Since chemical process generally progresses faster at warmer temperatures, the sun shining on the Viking lander would have produced such a rhythmic variation. The upshot was that the evidence was just inconclusive.

Levin fusses that nothing has ever contradicted his theory. The problem is though that to be sure that we've found life, we have to find evidence that could not have been produced any other way. While we are gathering mountains of evidence that most likely was produced by life, we still do not have that one last piece.

Short of seeing a Martian bug in a microscope, that level of certainty is going to be hard to come by. Even then we will have to rule out various scenarios of contamination by Earthly microbes that subsequently evolved to take advantage of the Martian environment. We can do that with statistical models, but we still will not know for sure the first time we see microbes on a slide.

[Chicago Astronomer - Astro Joe]

I think it's cool that Miller thinks that he sees circadian cycles in the Viking's sample analysis, but how could he determine this remotely, and with such an abbreviated time span of the sample examination?

I think that there are dormant life forms on Mars, in hibernation and spring back to activity once conditions are right. Similar to Earthbound organisms frozen in the deepest arctic, and re-animate after hundreds if not thousands of years in dormancy.

I too remember in 1976, following the mission and reading the results months later, (no internet),...and even as a 15 year old kid...could plainly understand the reaction of the soil samples in the rich medium soup that was offered.

And I agree that until we get an organism in a petri dish, the naysayers shall be obstinate and highly doubtful.

[Centaur]

Joe --

You sure are full of hopes and wishes on this issue. I admire your enthusiasm. Nevertheless, my hope is that you don't invest in the stock market using similar reasoning.

-- Curt

[Chicago Astronomer - Astro Joe]

Nope..my IBM and Microsoft stock are sound. No need for speculation or margin calls there. Spilt baby, split!

But apparently I'm not the only one who sees beyond the norm, and that's ok. Plenty of mechanically robot forums in the comfort zone, and discussing the possibility brings out-side-the-box thought...on either side or opinion. Even the theories of Velikovski are game..although a bit out.

Never a follower or one of the crowd...I'll just sit back and smile when the announcement is made...and a I told you so will never be uttered. But in retrospect, it will be sooo evident.

[Maddad]

Chicago said:

I think it's cool that Miller thinks that he sees circadian cycles in the Viking's sample analysis, but how could he determine this remotely, and with such an abbreviated time span of the sample examination?

The Viking Lander scooped up some Martian soil and added a nutrient broth to it. Then it looked to see if gasses were given off, and radioed the results back to Earth. It measured gas emission for several weeks as I remember. All this in the 1970's!

[Chicago Astronomer - Astro Joe]

I think that is totally remarkable that it accomplished this, and as well as the earlier probes like Surveyor and Lunik on the moon, the Russian Veneras on Venus and the great Pioneer's and Voyagers. All circa of the 1960's & 1970's. Sending back info in real time.

Voyager 2 is still sending back info, but pretty soon thru NASA cutbacks, no one will be listening.

Pretty sad...