| From: spud | 30/11/99
20:30:18 |
| Subject: Sounds from mars | post id:
12179 |
| In the article above it said the
polar lander would be searching for water. As water is needed to sustain
life. Is this exactly true? does every living creature need water to
survive on Earth? And isn't the assumption of water for life based on earth observations. is it possible other planetary biological lifeforms may not need water to survive, could they maybe live on nitrogen gas or vapour if that is what the lifeforms have evolved to survive on!? | |
| From: Paul | 30/11/99
22:19:28 |
| Subject: re: Sounds from mars | post id:
12236 |
| This is the classic "we haven't
seem it so it doesn't exist" frame of mind. Luckily the early space
pioneers thought of this and sent details of our carbon based lifeform on
the early rockets. We just have to hope that if there are lifeforms
reading it, they have a frame of reference that allows them to understand
carbon. cheers, Paul | |
| From: michael c | 30/11/99
22:38:39 |
| Subject: re: Sounds from mars | post id:
12244 |
| Hi spud, this is a great question, the processes of cellular life are complex. The energetics that drive these processes require long chain organic molecules, a fluid medium and the temperature range for electrochemical events to occur. For Mars to sustain life, it would need liquid water, liquid ammonia would likely not cut the third of the above (which are part of about 20 or 100 biophysical life postulates in my book) as the electron transfer to bio-quinonoids would be insufficient allow strong electron flow to develop oxidative (or other) metabolism, nor reductive metabolism (CH4 , H2S , etc reduction) . It would be difficult for a silicon based system as we have not observed on earth the long chain silicon based organic systems. However, saying this last point, could it be that to obtain long chain SiHnSm)j systems, do we need to be anaerobic, totally? Required liquid ammonia, lots of complexed Si and S, available H for redox interactions, complex C/Si/S/N systems to develop. Maybe we need a weird Chemist to look at such. Paul | |
| From: michael c | 1/12/99
11:06:21 |
| Subject: re: Sounds from mars | post id:
12354 |
| I think part of the reasoning
behind looking for water to find signs of life is based on the theory that
there has been a two way transfer of rocks between Mars and Earth, and
that some little critters may have gone along for the ride. If this had
happened, and they managed to survive on Mars, then they would most likely
be found near water. Michael C J | |
| From: Greg Mc | 3/12/99
2:14:47 |
| Subject: re: Sounds from mars | post id:
13028 |
| In simple terms, water is a very
important chemical for the existence of life as we know it. One of the
main reasons for this is that water is a very powerful solvent......
something that other chemicals can dissolve in. Like sugar dissolves in a
cup of tea. It is also very good for suspensions... like silt that turns a
river brown. In fact more chemicals can dissolve in water than just about
any other solvent known, and the interesting thing is that how well water
can dissolve other chemicals depends on its temperature. The best temperature is around our body temperature and this is fairly close to the body temperature of other animals. Even lizards and other "cold blooded"(poikiothermic) animals attempt to maintain their body temperature close to this range. Why is it useful for life to have lots of chemicals disolved in a solvent? Well, life is all about chemical reactions. Chemical reactions to release energy, or to build solid materials for the physical structure of organisms. By being dissolved in water, these chemicals can flow or be pumped around inside an organism to somewhere where they can react and produce an effect useful to that organism. Often, the water that is helping chemicals move around will take part in the reaction and be used up to form a new chemical, Sometimes it will be produced in a reaction. An element which takes part in almost all reactions involving living things is carbon. The branch of chemistry which largely centres on carbon is known as "organic chemistry" although this also includes the chemistry of plastics. The materials living creatures are made from are in many ways similar to the plastics we use in everyday life. Space scientists think that other forms of life may exist somewhere else based on other solvents such as ammonia or on elements such as Silicon rather than Carbon. We can not know for sure but we are sure about water and Carbon and so we search for life based on materials we are familiar with. Materials that have resulted in life here on Earth | |