Water as a life source.... WHY ?

Question

Now I fully understand that we need water to sustain life on earth... Life as WE KNOW IT ......but can somebody please tell me why in the search for life in outerspace .. we seem to tend to rule out planets that do not have water or a history of ever having water as being able to sustain life ?

Is it NOT possible for there to be a life-form that has evolved elsewhere in an absence of water.. therefore not requiring water at all ?

WE need water .. but other life-forms elsewhere ( if the exist ) may not ?

(to the science boffins who may be able to help me understand please use basic terms I do not have a scientific mind per se.. just an interest)

Answer 1

I believe so too.. there must be something existing somewhere that doesn't need water to survive. I mean the universe is vast. I believe that other planets from other galaxy sustains life.. What if there are life forms that uses chlorine as a life source? haha. just kidding.

great question :)

Answer 2

We are just looking for something familiar to us. We already know about our own type of planet that it just comes naturally. We wouldn't know what to look for in a silicon life form.There have been various theorys over the years as to what environments might support some kind of life, but until we actually get out there and explore we will never really kmow for sure.

Answer 3

Water is polar (it has a side to it, one side is slightly positive and one side is slighly negative), so it makes for a wonderful solvent (because it is polar, it can surround molecules of charged particles to break them up, so they can dissolve).  Since it's a good solvent, it allows for easy diffusion of molecules so it can get where it needs to be.

The molecules that make it up are relatively light weight, it has a low number on the periodic table of elements, so it's easy to believe that it will form spontaneously without breaking up (degrading) easily

On earth, most of evolution occurred in the water, we had to develop mechanisms to survive outside of water, such as skin, keratin coating,) to prevent drying out.  This goes back to water being a good solvent and medium for chemical reactions to occur.

water has a high heat capacity, which means it takes a lot of energy to evaporate it.  Thus, it stabilizes the environment (think of why coastal areas tend to not have large fluctuations in temperature), which is conducive to life (it's hard to survive if the temperature goes from zero to 180 degrees in minutes).  The reason for the high heat capacity is polarity (more sciency stuff I don't feel like explaining).

many of the characteristics of water can be applied to other chemicals, such as methanol and ethanol, but these are not as compact as water (molecularly speaking), so they are not as powerful and aren't as strong as with water.

Answer 4

I think it has more to do with the fact that hydrogen is the easiest element to bond to and oxygen bond's quite readily to hydrogen which thus provides an ideal form of energy when it is broken down (photosynthesised) etc.

I understand that Silicon and sulphides may also be possible candidates.

The splitting of oxygen from the hydrogen bond releases energy in an effective  and easily metabolised form.

Answer 5

Just like the famous letter 'Yes Virginia, there is a Santa Claus' I believe that just because you cannot see something does not mean it does not exist. There are animals that survive without actually drinking water on earth by being able to take in moisture in through their skin. There are a breed of frog that goes into hibernation when the lakes dry up for years and when able to get water wake up.

I believe that surely in this unending universe we are not the only planet with life on it no matter what form. There is probably another person on another planet asking this same question. I can not give you a scientific answer but common sense tells me other wise.

An interesting question, which prompts me now to look up the animals/insects etc that I remember reading about at school, thanks for the idea.

Answer 6

I'm sure I saw on the news that "they" have found some water on Mars. It might all be baloney, though. Someone somewhere may have a vested interest in some funding or persuasion of public opinion yadda yadda. Surely everything we see on the news these days is for someone else's reason. I'm not convinced to buy a house on Mars, anyway. haha. "They" would have a better chance of selling me an afterlife lifeform condo on a planet which would have no requirement for water.That might be harder to sell to everyone else though....