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Fraser
2006-Apr-22, 11:19 PM
SUMMARY: ESA's Mars Express spacecraft has completed an extensive map of minerals across the surface of Mars, pointing at the places future rovers might want to search for life. This new analysis shows that lakes and oceans might have been present on Mars, but they disappeared more than 4 billion years ago. That wouldn't have given life much time to get a serious foothold before the whole planet became a desert. So these pockets of hydrated minerals would be the best places to try and find evidence of past life.

View full article (http://www.universetoday.com/am/publish/mars_omega_life.html)
What do you think about this story? post your comments below.

trinitree88
2006-Apr-22, 11:34 PM
Although the geologic record may indicate long periods of cold dry Mars, the transient water events may bring larger impacts on possible life evolution than presently seen. The marine sediments on Earth that contain iron-60 do so from intrusions into the inner solar system by supernovae ejecta. When that happened, it rained, and rained , and rained. A supernovae may generate several solar masses of water, and the only way for an ejecta cloud to intrude all the way to Earth (thought impossible a decade ago)...is pass the orbit of Mars on the way in. Pete.:think:

astro-orange
2006-Apr-23, 12:41 PM
But, Pete, can you imagine the water vapor from a supernova could ever get to Earth dense enough to produce rainfall?! What if instead the cosmic radiation from the supernova event gave our clouds the seeding to then produce torrential falls? (Provided supernovas produced increased rainfall, which I didn´t know.) But it would still be true: our rain would contain parts from a supernova!

Now they have a new classification of the geological (or areological) history of Nergal! And what becomes of "Noachian, Hesperian, Amazonian"? Probably it is derived differently, from meteor cratering instead of minerals.

Edited to change menerals to minerals :-) !

GBendt
2006-Apr-24, 03:18 PM
Hi,

the more we learn about Mars, the more we become aware of the differences which exist between the conditions of the martian environment and the conditions of the environment of the earth. This is fascinating.

We have some ideas of the conditions under which life on earth developped. There is also the idea that life might have set foot on Mars billions of years ago, just as life set foot on our own planet.
On the other hand, we have very little precise knowledge of the early life forms on earth: 99,99 percent of all the species that ever lived on our planet are extinct. There is still a lot of investigation and research to be done.

Currently, it is most likely that we know less than one millionth of the species of archea, bacteria etc. that are existing on our planet. If this is so, we cannot positively tell whether there are conditions at which none of these species may thrieve. Whereever we did nor expect to find life forms on earth, we found some.

E.g., I read we discovered an archea which lives in hot boiling water. This archea stops to multiply when the temperature of the water in which it is living falls below 108°C. Its favorite temperature is 118°C. Who would have imagined to find anything living like that?
We should be prepared to find bacteria which live in boiling acid, which is rich in poisons like lead, barium, copper, or cadmium. It may be that any environment may house its special set of species, which specialized to live in that environment, as long as there is liquid water in this environment, and some source of energy. Mars does offer such environments.

Many people have the opinion that supernovae are the source of almost any molecule which exists in the universe. This, however, this is not the case. The atoms of all elements that are heavier than helium are created by nuclear fusion processes in stars and by supernovae. Molecules, however, usually form in the matter of dense solar winds which are generated by Red Giant stars, which shed up to 1e25 kg of matter into space, per star and year. from this matter, the huge molecule clouds finally form in which new stars and their planetary systems are born within a long process.

A billion degrees Kelvin, as can be found in supernovae, is too hot for molecules, and when the supernova cloud has expanded and thus cooled down, this cloud spans tens of lightyears and has become too thin to foster chemical reactions effectively.

Regards,

Günther

trinitree88
2006-Apr-24, 03:55 PM
But, Pete, can you imagine the water vapor from a supernova could ever get to Earth dense enough to produce rainfall?! What if instead the cosmic radiation from the supernova event gave our clouds the seeding to then produce torrential falls? (Provided supernovas produced increased rainfall, which I didn´t know.) But it would still be true: our rain would contain parts from a supernova!

Now they have a new classification of the geological (or areological) history of Nergal! And what becomes of "Noachian, Hesperian, Amazonian"? Probably it is derived differently, from meteor cratering instead of minerals.

Edited to change menerals to minerals :-) !

Astro...my point was that three solar masses of water is roughly three million times the mass of the Earth in water. Since the ocean, as is makes up a small percentage of Earth's mass....a prolonged rain on Mars would have pronounced effect on Martian geochemistry, and set the stage for evolutionary chemistry with water being present. It need not be miles deep to do so.

Gunther. As a chemist, I'm quite aware of the chemistry of cooling ejecta, with refractory compound forming first...olivine, pyroxene, silica, but an exploration of the relative abundances of elements produced there by Woosley et al yields dozens of nuclides. Once the rains begin, and atmospheric chemistry kicks in, lots of molecules are possible in a wet Mars scenario, independent of molecular synthesis in red giants. Harold Urey showed that many moons ago. Pete.

GBendt
2006-May-03, 07:02 PM
Hi

Water is a very common matter in space. You do not need a supernova to create it. Every Red Giant casts up to 10E25 kg of matter per year into space by its usual stellar wind. This matter contains a lot of oxygen, and a lot of hydrogen, which may finally react in creating water molecules.

A supernova may well cast several solar masses into space at a time (at a speed of 40000 km/s, at at a temperature of a billion kelvin), but as the cloud of extremely hot matter expands rapidly into space, it is distributed in it. When the cloud of debris has grown to a diameter of some lightyears, the concentration of matter in that cloud has fallen considerably. A sphere with a radius of one lightyear contains some 4E39 cubic kilometers. If you have 6 solar masses within that sphere, this results in an average density of 3 nanograms per cubic kilometer: This is an excellent vacuum.

If a Red Giant blows 1E25 kg of matter into space within a year (at a temperature of 3000 kelvin and at a speed of 40 km/s), the average density resulting from this at a distance of 1,5 billion kilometers will be some 100 micrograms per cubic kilometer. This is a much denser concentration than that of the supernova cloud, and that Red Giant will go on producing a stellar wind which casts 1E25 kg per year for thousands of years. The supernova, however, explodes only once. The sky is dotted with Red Giants, but supernovae are a scarce view, for which generations of astromers have been yearning in vain since the last one, observed by Johannes Kepler in 1680.

Cosmic radiation can ionize particles in the atmospere of a planet, and these charged particles may support the building of droplets which may finally fall as rain. The water in that droplets is in the atmosphere, and not from a supernova.

A mass of several million Earth masses is not much in the terms of the universe. The Orion nebula is said to contain 2000 solar masses, and the Tarantula nebula near the Small Magellan Cloud is said to contain 150000 solar masses.
Research based on data from the ISO satellite in 1998 revealed that the Orion Nebula produces enough water in one day to 60 times fill the oceans on our planet.

Regards,:)

Günther