Nasa is to reveal Mars water secrets...

[sumner7]

@blobrana

I like your new avatar a lot.

[KennyR]

Speelgoedmannetje wrote:
Well, in the deepest parts of the sea here on earth, weren't there lifeforms based on sulphur (and so), other than well where we're based on?


so these probably work different.

Why HAS it to be green?

Nope, it's a matter of chemistry. At the temperature ranges where water could be used as a solvent for life (0-100C of course), green chlorophyll happens to be the most efficient chemical for photosynthesis. There are other kinds - brown, red...but these are a lot less efficient and are used by plants that don't have any other choice, like deep seaweeds. It's hard to imagine single-celled bacteria with brown or red chlorophyll being able to survive in the limited sunlight and low temperature Mars provides.

[Speelgoedmannetje]

green chlorophyll happens to be the most efficient chemical for photosynthesis

How do you know that? Source? :-)

[KennyR]

green chlorophyll happens to be the most efficient chemical for photosynthesis

How do you know that? Source?

Look outside.

Evolution is a hard taskmaster. It always goes for the most efficient processes. Less efficient ones just die and disappear, except in places the more efficient ones don't work.

[Speelgoedmannetje]

IF evolution 'found' a better way.

Nature is far far far from perfect y'know. And evolution is still going on.

And why should it be green on Mars? Maybe there's happening the same, but less/more efficient.

[redrumloa]

Well, in the deepest parts of the sea here on earth, weren't there lifeforms based on sulphur (and so), other than well where we're based on?

\

Agreed. I am certainly no Mars expert, nor any other expert;-) But I think it is foolish for scientist to make blanket statements like "Life is only possible under X-condition". Finding life thriving in the deepest parts of the earth's oceans shook alot of things up:-)

[KennyR]

Speelgoedmannetje wrote:
F evolution 'found' a better way.

Nature is far far far from perfect y'know. And evolution is still going on.

It had about two billion years to perfect photosynthesis before animals started to appear. It's had plenty of time. There is nothing more efficient than blue-green chlorophyll, because if there was, it would be here.

And why should it be green on Mars? Maybe there's happening the same, but less/more efficient.

Then where is the oxygen by-product?

[Seehund]

KennyR wrote:

Blobrana wrote:
i`ve got a feeling that mars is crawling with underground lifeforms...er, like the earth...

Well, they obviously don't use sunlight, or Mars would be green. So they would have to live off warmth and sulphides produced by volcanism. Trouble is, unlike Earth, Mars cooled out a long time ago. No more volcanism. So where would they get their energy from?

Organisms don't necessarily have to live off any warmth. Ambient temperatures that don't stop the essential cellular processes from taking place (and possibly creating their own metabolic warmth if need be) should be sufficient.

Photosynthesising lifeforms wouldn't have to be green. If Martian plants/algae/whatever use a chlorophyll-like isozym for photosynthesis it would probably be adapted to Martian light, together with the plants' pigmentation like deep-sea algae, cyanobacteria et c. How long has the Martian sky had the same colour that we see today? An evolutionary significant amount of time? And single bacteria-sized organisms here and there don't really have any discernible colour.

We're still talking about hypothetical lifeforms in a largely unknown environment on another planet, and yet we're applying rather specific Earth biology on our speculations... And how should we define "life" on Mars to begin with? Is a self replicating nucleic acid life?

[Seehund]

KennyR wrote:

Speelgoedmannetje wrote:

And why should it be green on Mars? Maybe there's happening the same, but less/more efficient.

Then where is the oxygen by-product?

It's there, but only 0.6% of what we have on Earth. Then again Mars doesn't exactly appear to crawl with life like Earth.

But now we make the IMO rash assumption that the Martian photosynthesis, if it exists at all, works like it does on Earth.

[alx]

You can see and hear what's happening here

[sumner7]

alx wrote:
You can see and hear what's happening here

Interesting.  :-o

[blobrana]

Hum,
(and for those withut Realplayer...),
so basically NASA  has reported compelling evidence that the tiny crater that the Mars rover Opportunity has been scooting around for the last month was once soaked in water.


"Liquid water once flowed through these rocks. It changed their texture, and it changed their chemistry,.
The finding greatly enhances prospects that Mars was a much more hospitable planet early in its history, possibly even amenable to the rise of life at one time.
There were several key lines of evidence to support the conclusion, including the presence in the rocks of sulphate's and small spherules that were probably precipitated out of water.

The rocks' physical appearance,
http://marsrovers.jpl.nasa.gov/gallery/all/1/m/034/1M131201699EFF0500P2933M2M1-BR.JPG
such as niches where crystals once grew, also helped to prove the case. It seems to have formed in water or, after formation, have been highly altered by long exposures to water. Jarosite may point to the rock's wet history having been in an acidic lake or an acidic hot springs environment.




Pictures from the rover's panoramic camera and microscopic imager reveal the target
http://marsrovers.jpl.nasa.gov/gallery/press/opportunity/20040302a/16-jg-02-mi1-B035R1_th200.jpg rock, dubbed "El Capitan," is thoroughly pocked with indentations about a centimetre (0.4 inch) long and one-fourth or less that wide, with apparently random orientations. This distinctive texture is familiar to geologists as the sites where crystals of salt minerals form within rocks that sit in briny water. When the crystals later disappear, either by erosion or by dissolving in less-salty water, the voids left behind are called ...VUGS!..., and in this case they conform to the geometry of possible former evaporate minerals.
http://marsrovers.jpl.nasa.gov/gallery/all/1/m/033/1M131117272EFF0454P2953M2M1-BR.JPGhttp://marsrovers.jpl.nasa.gov/gallery/press/opportunity/20040302a/07-ss-07-moess1-B038R1_br.jpg


Hum, i thought so...

[sumner7]

There must definitely be some life form on mars if liquid water has been found.  :angel:

[cecilia]

let's not get nutty!
 :juggler:
it seems there hasn't been water on mars for a looooooog time.

unless something can hybernate for millions of years and if you drop some water on it suddenly wakes up, we ain't seein' no martains.

 :banana:

[Speelgoedmannetje]

Seehund wrote:
But now we make the IMO rash assumption that the Martian photosynthesis, if it exists at all, works like it does on Earth.

Thanks in advance :-), Seehund, to express my thoughts

[blobrana]

Yea, there hasn`t been liquid surface water on-mars for a loooong time...
But just below the surface and maybe to a depth of 20 miles there could be ... and life may continued to survive there...

There have been recent studies of the life forms on earth. And it seems as if there is more bio mass living inside the earth than in the surface seas or jungles...

"The  Spirit rover has also found more evidence that water once existed on Mars, following close behind Opportunity that sits in a region that was soaked by water in the distant past.
 Spirit made its find by studying Humphrey, a 23-inch (60-centimenter) tall rock at Gusev Crater. The rover found that despite the rock's volcanic beginnings, water apparently seeped through it at one time, allowing minerals to crystallize inside.
Extensive studies of Humphrey with the multiple science tools on its robotic arm, which included drilling into Humphrey with the rock abrasion tool (RAT) then taking images of the area with the microscopic imager, Spirit detected fractures in the rock filled with minerals that were most likely formed in the presence of a tiny amount of water."

[Ancestral archaebacteria were probably heterotrophic, anaerobic, sulphur-dependent hyperthermoacidophiles] :-)