Why is water considered essential for life on other planets?

There may be a good scientific reason for this, but why is it impossible for life to develop on another planet based on anything other than carbon?

For example, surely it would be possible to have a Tungsten based life form? Or, from an undiscovered element?

Why do scientists say they can only be life on Mars if water once existed?

✅ Answers

? Best Answer

The major reason is because ALL life on earth (and therefore all life we know of) is absolutely dependent on water.

While it is obviously theoretically possible for life to be non-water based, such life would have characteristics we cannot even begin to guess at, so we might not even recognise it if we were looking at it. So it is simplest to assume all life is water-based, and to base our searches off that.

Another reason is because it is also a fairly safe assumption that all life is also carbon-based. Carbon chemistry is what provides the amazing complexity of organic compounds: it forms long-chain molecules, it can be charged (+ or -), it can be hydrophobic or hydrophilic, etc. All this complexity is an absolute requirement for the huge number of different molecules and chemical interactions that comprise “life”.
No other element can do this (silicon comes close, but it is still much, much simpler), and it is only in the presence of water as a solvent that all these complexities actually come to be.

So, if we assume that all life is carbon based, it must also be water-based.

(and life baed on an undiscovered element is even less likely, all the heaviest elements are radioactive and not very chemically reactive – and the same is true of every single new element humans make, like unnilpentium, unununium, etc.)
– Chosen by Asker

Only certain elements are capable of forming chains and form long molecules necessary for life rather than chemical reactions. these are in groups 14 or 15 of the periodic table Silicon, Carbon, Nitrogen, Phosphorous, these need elements form group 1 and 16 of the periodic table to combine with (hydrogen, Oxygen, Sulphur).

Metal based lifeforms are not reasonably possible as although they can form compounds and crystals they cannot be the basic of long chain molecule although CAN be used within a long chain molecule as a nucleus (eg Iron in Haemoglobin)

The assumption is that from experience life needs to be CARBON based and in order for carbon based life to work it needs, Oxygen, Carbon Dioxide and Liquid water to metabolise, in a oxidising environment.

if the Life was based on nitrogen then it would exist at lower temperatures and need ammonia and hydrogen as its a reducing environment

however if its based on silicon it would be a high temperature environment and would need oxygen or hydrogen (either oxidising or reducing environment) and would most resemble a biologic microprocessor type

It has been speculated that other life forms may not be carbon based but silicon and other members of this group because they have 4 electrons that are capable of binding and therefore the amount of compounds that can be formed with these as a base is much greater. This is the main logic behind carbon based life. Water, every living thing on this planet is tied to water someway. Some life forms can live without oxygen but everything needs water in some way, shape or form.

Till date we consider water as the universal solvent. Various properties like neutral pH, coolant properties, abundance, temperature friendliness etc make it unique in our planet.

Next to earth mars has been considered as the planet susceptible to human life.

So any other fluid can prove to be abrasive in nature and can prove to hinder the osmotic pressure regulations . Thus preventing the carrying out of a coordinated body metabolism.

I think organic chemistry can answer your problem. You see, living organisms is composed of cell which has the basic C, H, and O elements. Undoubtedly, water is a good source of hydrogen and oxygen and it is a stable compound. So without the presence of water, it will be impossible to believe that life will exist on Mars.

u raised a good point but being a science student u must be
well acqainted with properties of water.
1)it is the greatest solvent,a universal solvent.
2)it has high sp. heat capacity.it prevents large variation in temp.
3)it acts as ele. donor.
variety of chem. reaction occur in solution.
and numerous other properties.

now can u tell me an element which has all these properties
together,is easily available and can be produced so easily?

now u say about tungesten part or any other element which is
not yet discovered.
so now let me ask when these elements are so so rare component of earth how can u expect them to form integral
part of every living being on earth and exist in such varied forms(u know ur body is composed of carbon chains with high mol. wt).also carbon is self regulatory,there is a carbon cycle which regulates the carbon on earth.
if any other element is there in that place say tungesten,how will it get regulated?

now for that third part,i would say that it is the position of mars from sun which is behind such statements of scientists

huh!got that

I don’t get it either, we base what we are looking for on our knowledge, but as far as know, there could be a species out there who drink suplhuric acid, and eat mud. There could even be other elements out there which do not occur on earth, which coulld do the same job or be better than water. It seems slightly arrogant that we seem to have decided what is and isn’t possible, when really we have no clue.

It’s a very good question. Sadly we are only in a position to comment based on the knowledge WE have, but you’re absolutely correct.

We may not know every element out there and there could be a life form that needs, I dunno, cheese to survive

As nothing can live without it on this planet we have no means of tell otherwise about other planets

how could you make a cup of tea without water? no tea, no civilization