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Why Is Water Important For Life To Exist In The Universe

Melvin is an avid reader and a retired chemist after working for a major pharmaceutical company for 32 years.


Earth is the only planet that we know of that currently has life on it in the observable universe. The other planets in our solar system have not shown any indication of life on them based on our understanding of it. Even the hundreds of earth like planets discovered in other star systems have not shown any telltale signatures of life on them. That is, water must be present in order for life to exist here and probably everywhere else in the universe with one critical criterion, it must exist as a liquid or no activity of life will engender in a dry or even frozen environment.

Water plays a critical role in life since in just about every biochemical reaction that takes place in a living organism depends on it to produce all the necessary ingredients to sustain it. There is no other substance or molecule in the universe capable of interacting with as many of the elements in the periodic table as water to produce hundreds or even thousands of chemicals for life to exist. This is why water is essential and so imoirtantfor life as we know it to exist.

Microscopic organisms in a drop of seawater. This image was magnified 25X

Microscopic organisms in a drop of seawater. This image was magnified 25X

LifeStraw Water Bottle With LifeStraw Filter

The Characteristics of Water that Makes It Possible For Life to Exist Here

It Exist Simultaneously in Three Physical States

Let us look at water from a chemical perspective. Water is a relatively simple substance composed of two hydrogen atoms and one oxygen atom, thus the shorthand chemical name H2O. On earth water, which covers about 71% of the Earth’s surface, exists simultaneously in all three forms as a liquid, a solid (ice) and a gas (water vapors). It is this characteristic of water under the physical conditions on Earth that make the existence of life possible here. If water cannot exist in these three states at the same time on a planet life cannot exist. That means the planet is not in a habitable zone for life. It is the only substance that exists naturally in all three states. Water has been found on many of the planets in our solar system but not in all three states simultaneously.

For example, water vapors have been found on Mercury, Venus, Mars, Jupiter and Saturn but not as a liquid on any of these planets. Also none of these planets are in the so-called “Goldilocks Zone” to be habitable for life. Ice has been found on Mars; the moons of Jupiter and Saturn and even on our own Moon, but again these are all inhabitable places for life. Water has even been detected in interstellar space and on some of the recently discovered exoplanets but the water there probably does not exist in the three states simultaneously to support life. In some cases the atmospheric pressure on some of these planets are so great that water only exist as ice no matter how warm it is on the planet.

It Has A High Specific Heat Capacity

I know some of you are probably wondering how we are able to detect water so far away from Earth. It is simple. Water is a strong absorber of ultraviolet, microwave and infrared (heat) light due to the vibration of the hydrogen-oxygen bonds. This is why food get hot in a microwave oven because the water molecules are absorbing the microwave which causes an increase in the vibration of the atoms, thus producing heat. This physical property of water is another characteristic that makes life possible here. When water is heated it does a very good job of holding that heat because it has the second highest specific heat capacity (the ability to hold heat) of all the substances known. This property gives water the ability to moderate the earth’s climate to make it possible for life here.

Almost Everything Dissolves In It

The property of water that really set it off from the rest of the substances on Earth that makes life possible is its ability to dissolve just about anything such as salts, acids, bases, sugars, and gases. It also dissolves proteins and DNA the main components of organisms on earth. In light of this a new bacteria capable of utilizing arsenic was discovered in a lake in California. Arsenic ions are soluble in water to make this possible, This is also the reason why arsenic is toxic to organisms because it is soluble in water as Arsenate, a compound similar in chemical structure of a very important water soluble compound, phosphate.

Strong Surface Tension

Finally, water has a strong surface tension, the ability to stick to surfaces and be elastic at the same time. This property makes it possible for plants to draw water with dissolved nutrients through its roots and makes it possible for blood to circulate through our body.

Evidence of flowing water was recently found on the surface of Mars which raise the possibility that  life may be there or it was there.

Evidence of flowing water was recently found on the surface of Mars which raise the possibility that life may be there or it was there.

Life Probably Started Here and Out There In An Aqueous Environment

If there is life on other planets out there it probably started the same way life started on Earth, in an aqueous environment. Molecules have to be close enough to each other for any interaction to take place. Life forms on other planets probably went through some form of evolution from something simple to something more complex just as it happened here due to chemical interactions of molecules present in the water.

All 118 elements we have discovered in the periodic table also exist everywhere in the universe and they would follow the same physical and chemical laws since all the elements originated from the stars throughout the universe.

The processes of life on earth are controlled by a relative few core elements in the periodic table, namely; Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus and Sulfur (The Big Six or CHNOPS) with trace amounts of other elements. These elements make up the main components of an organism; the nucleic acids in DNA, proteins, and lipids (fatty substances).

Most likely organisms in other parts of the universe are probably made up of the same main elements as the organisms here on Earth with a few minor exceptions. For example, the recent discovery of bacteria in Mono Lake in California contains Arsenic instead of Phosphorus as one of their core elements. This data is currently being disputed among some of the scientists that this is not possible. Obviously based on these facts, scientists are not expecting to found another organism on some distant planet using plutonium in their system as one of the core elements to live because it only reacts with a relatively few elements. The resultant compounds do not seems to be of any use biologically.

Now all this bring us to the inescapable conclusion that water must be present in order for chemical reactions to take place for an organism to develop and move forward to a more complex life form. We know all biological processes in organisms on Earth take place in an aqueous environment and the reason that happen because water plays a crucial role in most of these biochemical reactions for processes such as reproduction, cell division, and metabolism to take place.

There is no other substance besides water that these reactions can occur in since many biological chemicals are soluble in water. So most likely biological processes in other parts of the universe must also occur in an aqueous environment and the processes out there on other planets must involve the same basic six elements used here. For example, there are not too many gaseous molecules we can breathe in such as oxygen to add to an equation to extract energy in our system and breathe out the by-product as the harmless gas carbon dioxide.

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Carbon and oxygen have a unique ability to combine with many elements, especially hydrogen, in different combinations to cause a lot of these biological reactions in the organism. Another example, photosynthesis will not be possible if the chlorophylls in plants could not combine Carbon, Hydrogen, and oxygen with a photon of light from the Sun to produce energy and food for plants. There is no other combination of elements in the periodic table that can replicate this very important chemical reaction in plants.

You only need five elements to make the DNA structure of life

Only five of 118 elements in the periodic table are  needed to make a DNA structure in an animal or plant

Only five of 118 elements in the periodic table are needed to make a DNA structure in an animal or plant

Bacteria in lake water.

Bacteria in lake water.


Water is obviously the main ingredient for life to exist here and probably anywhere in the universe, but it must exist in all three forms on a planet in a habitable zone in order for it to work. Microbes would probably be the most prevalent life form in other parts of the universe just as it is here.

If the planet is too hot there will be no water in the liquid state for any chemical reactions to take place to support life. The molecules will never come to together to create life and eventually evolve into a more complex organism. Also the organism may not survive the extreme heat since water broils at certain temperature depending on the atmospheric pressure.

On the other hand, if the planet is too cold the water would exist as ice. No chemical reactions will occur or chemical reactions would extremely slow, since the necessary elements will never come together to support life. If you look at this another way, we and other organisms on this planet survives because water has a wide temperature range as a liquid, that is, from 0°C (32°F) to 100°C (212°F). If for some reason the Earth was moved out of the habitable zone to temperatures outside this range we will not survive very long simply because water does not exist in the liquid state outside of this range.

© 2011 Melvin Porter


Melvin Porter (author) from New Jersey, USA on February 08, 2016:

Credence, thanks for well written comment on my hub. I agree with. The universe is vast and because of this the probability for life to exist in other chemical combinations are just as immense as well. But, on the flip side, this may be the only life can exist in the universe with carbon and water as the main component for it to exist. Keep in mind, in the elements we have discovered so far in the universe are same elements no matter where you are located in the universe. All the elements have their origin in the stars out there.

Credence2 from Florida (Space Coast) on February 07, 2016:

How have you been, Melvin?

Water is a necessary component for life as WE KNOW It. I have read speculative literature that life based on other foundations other than carbon based is possible. It has been a while, but you can Google. Instead of the Carbon, Oxygen, with water as a solvent, what about Silicon in the place of carbon? Generally making a form of life that thrives in temperature much higher than those found on the earth. Perhaps at temperatures above the boiling point of water at sea level. Of course, the mediums for respiration and solvent if relevant would be quite different. Or we could go the other way, I have read that perhaps Ammonia could be a solvent much like liquid water for a life form, fundamentally different from our own, and one that could thrive in extreme low temperatures not possible on Earth, Titan would be an interesting celestial body for study.

This article has piqued my interest and I will check on some of the speculation further. I don't have all the answers, but if the universe is as diverse and possibilities endless as I imagine them to be, I would not embrace a single template or limiting parameter as to what would make life possible.False-color Cassini radar mosaic of Titan's north polar region, blue areas are lakes of liquid hydrocarbons

"The existence of lakes of liquid hydrocarbons on Titan opens up the possibility for solvents and energy sources that are alternatives to those in our biosphere and that might support novel life forms altogether different from those on Earth."—NASA Astrobiology Roadmap 2008[1]

Melvin Porter (author) from New Jersey, USA on September 28, 2014:

Thanks Watergeek. This article is about life as we presently understand it, but it highly likely that water and other chemicals in the universe must play some role in supporting life in one form or another throughout the universe and many compounds are readily soluble in water to make life possible here. Besides, everything in the universe are made of some combination of the 118 known elements we have discovered so far to exist physically in this universe we know. Bear in mind that all these elements originated in all the stars scattered throughout the entire galaxy and eventually engendered life on this planets and probably on many other planets scattered throughout the universe.

Susette Horspool from Pasadena CA on September 27, 2014:

I agree with Qwark. We don't know what else is out there. We do know about our Universe and the dimension in which we live. It's the one we've studied. But what if there are other dimensions of living with "bodies" that are primarily energy and don't require water? We Westerners define "life" as having a physical body, but what if that's not the only form life comes in?

This article could be differently titled: Why Water Is Essential For Physical Life As We Know It, for example. And still, it's very well written Mel.

Melvin Porter (author) from New Jersey, USA on September 10, 2014:

Watergeek, thanks for your comment on my hub.

Susette Horspool from Pasadena CA on September 08, 2014:

Good article. It's amazing how differently people can write about the same subject. Many of the facts you bring out here I hadn't thought of, although they're valid and interesting points.

Achilefu o Ere on April 26, 2012:

The approch is welcoming

Lance on April 02, 2012:

The truth about universal laws is that we are only as well informed about their truths as we are about their verifiable nature as they've been revealed to us through empirical testing that always nets the same result. Universal laws of physics and nature are based in eternal truths that are discovered in time, typically when their principle or properties become necessary for the further expansion of our knowledge and understanding of the workings of our physical universe. The architecture and outworking of our known universe are in accord with the truths the govern the elemental properties and working principles of all that we are and the environment we exist in.

Melvin Porter (author) from New Jersey, USA on December 22, 2011:

Bagsofwater, thanks for your comment. The problem with all these newly discovered planets are that some do not possess habitable conditions for life as we know it. One is too hot and other is simply too big and is a gaseous planet like Jupiter. In other words they are not quite like Earth in a lot of other ways.

bagsofwater from USA on December 21, 2011:

great hub! you made a complex subject easy to understand and proved it visually, thus i'm very curious what you think of the recent findings Kepler 20e, 20f and 22b, I wrote a couple hubs on those myself.

Melvin Porter (author) from New Jersey, USA on December 13, 2011:

Mattforte, these evidence may change the assumption that the universe is not the same all over, but the same elements may still exist everywhere in the universe since all elements have their origin in the stars and from the same sub-atomic particles that were there during the early moment after the Big Bang explosion. This evidence could indicate that we are probably the only life form in the universe. That we may truly be here purely by chance.

As far as the discovery of arsenic in bacteria goes the data from that discovery have been verified to be inconclusive. The latest results on this discovery show no evidence of arsenic in the chromosomes of these bacteria.

Steven Pearson from Bonney Lake, WA on December 13, 2011:

Nothing we know is universal truth. We believe that water is necessary, because we have not observed anything else. However, we also recently discovered a species that thrives off of arsenic - previously thought impossible.

The truth is, everything about everything is only theory. Even saying the laws of physics are the same throughout our universe is not necessarily true. We believe that to be, but there are theories otherwise...

Melvin Porter (author) from New Jersey, USA on May 22, 2011:

Ione77star, thanks for your comment. You are right I forgotthe requirement that an atmosphere is require to support life. Obviously, without it the water will simply boil off since there is no pressure to keep it in the liquid state. Again thanks for stopping by to read my hub.

Rod Martin Jr from Cebu, Philippines on May 22, 2011:

Melpor, outstanding! You cover all the bases on this one. Very nice.

I think a planet could grow and support life, though, with only two states of water. Is ice really necessary? I think in some times of the past, Earth may have had no ice at all. I can envision a "Goldilocks zone" planet having no ice, but plenty of water -- say 2-4 times the mass of Earth so that mountains are shorter and adiabatic lapse rate does not result in snow-covered peaks. Hmmm-m-m, but I suppose you'd still have ice crystals in some of the stratospheric clouds, though none on the planet's surface.

Also, "these are all inhabitable places for life" (paragraph 3) might better be stated as "uninhabitable."

Along with your requirement of water, we also need to have a planetary atmosphere. On a world without air, water either boils away or sublimates.

Finding through spectroscopic analysis of exoplanets the presence of water vapor on a Goldilocks zone planet would be "holy grail" for space enthusiasts. I hope I live to see that discovery. I've only been waiting 56 years for it.

Melvin Porter (author) from New Jersey, USA on March 05, 2011:

Mike's Corner, thanks for reading my hub. Water is an important ingredient for life here because many chemical reactions that support life involves water at one point or another in the chemical equation. I would think this same thinking applies to other habitable worlds in the universe also since the same elements exist everywhere in the universe.

Mike's Corner from Maryland on March 05, 2011:

Fascinating hub, Melpor, great work!

Shahid Bukhari on February 22, 2011:


Science, to me, is the other name of Quanta, and Exactitudes, as the means of Defining, what to the Seculars is a purely Physical Reality.

Two things, however, Divest all Scientific and Philosophical Cognitions of the Existential's Reality, these are 1. The Irrational's allowance in Theory [Philosophy], and the Irreconcilability of the Present, with its Real Origins ...

Because, Science, and Philosophy ... both, are subject to a malady, called the "Missing Links' phenomenon ... take any Theory, or Experimen viz. the LHC at Cern; or be it the 2008 Nobel Prize wuinning Theory about b-Mesons, or the other winning the 2010 Prize for a study of the Gene .... one, representing the Genesis of Matter, and the other dilating upon the Evolution of one of the Human Genome's Constituent.

Al' Quran [Koran] lays down the Laws, which govern The Existential Truth of Reality ... I follow The Word, In Belief, and have written quite extensively here in these Pages, while dilating upon The Law, in replying to the Unanswered Questions of Sciences and Philosophy.

Melvin Porter (author) from New Jersey, USA on February 22, 2011:

Shahid, thanks for you comment and for stopping by. Science knows a lot about life now. Researchers now know how life probably was started some 3.5 billion years ago. They were able to reproduce the primeval conditions in the lab and produce the first building blocks of life in a flask. They still do not know how these molecules gain the ability to self-replicate. Keep in mind for life to exist here and anywhere else in the universe, water most likely must be present for the chemical reactions to make life possible, otherwise life will be impossible. The same 118 elements in the chemical periodic table are in other parts of the universe with the same properties as here since all elements originated from the stars.

Shahid Bukhari from My Awareness in Being. on February 22, 2011:

Science knows a little, about the life forms of Earth ... while Science Fiction, with the help of Computer Graphics, is still Speculating, whether there is life out there ...

And if there is Extra Terrestrial life, what Form does it have, and whether, it is Superior to the Humans in Intelligence ... etc..

Al Quran states in Chapter 42, Titled "Believers should be Patient" ... Verse 29, I quote :

"And of His Signs, is the Creation of Heavens [Universe] and the Earth; He hath Spread Forth in them of Living Animals. And He Is All Powerful, to Gather them Together, when He will. "


So I, in the capacity of a Muslim, Know, without any doubt whatsoever, that there are "animal like life Forms" out there, described, in the verse quoted at # 2 below.

Regarding Creation of Life, Al Quran States ... and I quote ...

1. "Do not those, who don't Believe, see, that Heavens and Earth were Conjoined, then we split them Asunder ... And We Made from Water, Everything Living. Will they not then Believe ? "

Re: Al Quran; Chapter 21, Titled The Prophets. Verse 30.

2." Allah hath Created every Living Animal [encompassing the Extra Terrestrial Life Forms] of Water [H2O] So of them, is that Crawls, upon its belly, and those which walk upon two feet, and then which walks upon four ...Allah Creates, what He Pleases, Surely Allah is Possessor of Power over everything "

Re: Al Quran, Chapter 24, Titled, Establishment of Kingdom of Islam.

Melvin Porter (author) from New Jersey, USA on February 07, 2011:

Dahoglund, thanks for your comments. It does seem like it took a lot circumstances for life to exist here, water being the main integredient for it to happen. This is why scientist are looking for planets where water exist as a liquid. A lot of the chemical reactions had to occur for life to exist here and most of these reactions would not had occurred if it wasn't for water.

qwark on February 07, 2011:

Hi Mel:

I understand all of that and the reasoning it would lead one to.

WE "think" we have it covered.

All I'm saying is that the "possibility" exists that that's not so.

That there still may be mysteries to unfold.

WE know that "dark matter and energy exist" subjectively but not objectively.

There exist "things" like "quarks" in the "quantum world that exist subjectively but not objectively.

You see what I mean?

There are still so many problems to be solved in the field of physics.

There are still so many enigmas still existing in "our" universe that it would be arrogant of us to think we have it down "pat."

You are "right" in all you have presented.

I posit that there is, still, much more to be "known"

and that life may exist that we couldn't dream of.

I'm a "dreamer," I know.



Don A. Hoglund from Wisconsin Rapids on February 07, 2011:

It does seem like it takes a unique collection of circumstances such as water to have created life as we know it on Earth.

Melvin Porter (author) from New Jersey, USA on February 07, 2011:

Qwark, all the stars and other planets in in the universe or at least in this universe are composed of the elements in the periodic tablet. Rationally, speaking there is no reason why there would be entirely different elements out there and the remainder of the elements out there are short lived ones based on the periodicity of the periodic table. The periodic table is probably just about complete as far as the elements are concern. I really doubt there are that many more to be discovered. Also the physical laws would be the same everywhere in the universe, for example, the speed of light is the same no matter where you are in the universe. This is why if there is life anywhere else in the universe there is very high probability water is involved for it to happen. Most chemical reactions especially for life need water to work even if the other life form is using different elements. This is also why astronomers are looking for planets just the right distant from their stars to support life because if it is there is most likely water there in the liquid form.

Melvin Porter (author) from New Jersey, USA on February 07, 2011:

TahoeDoc, thanks for your comment and compliment. You are one those smart people reading my hubs.

TahoeDoc from Lake Tahoe, California on February 06, 2011:

Melpor, I just really enjoy your hubs. If I was as smart as you, I could have been a chemist or other 'real' scientist. But, alas, I could only manage medical school (very safe, predictable regimented) :) Thank you for the fun and intelligent hubs! And also to the smart people who comment on his hubs.

qwark on February 06, 2011:


It would be logical and reasonable to say "yep yer right!"...but I can't.

Universal laws may be as we think we "know" them to be,

but the possibility exists that we have only begun to understand our universe.

Energies, forces, elements "might" exist out there that we can't imagine yet.

We have a grasp on the "basics," for sure, but the TOE has yet to be completely understood. Then? what next?

Knowledge and understanding is beyond googolplex!

Other universes? You bet!

Thanks for the thought.


Melvin Porter (author) from New Jersey, USA on February 06, 2011:

Qwark, thanks for your comment. But remember the laws of physics is the same everywhere in the universe. Gravity is different on the another planet but it only effect the shape or form of the organism. This life form will still require the same elements as the organisms here on earth have used. The compounds and molecules will be the same and the only way they will be different is if you start talking about another universe where the laws will be different. Then life may never exist became the laws are different in that universe.

qwark on February 06, 2011:

Yep Mel:

It seems that the laws of physics and chemistry are pretty stable in OUR universe.

But ya never know.

All of what you explain is "logical," based upon what we "know."

The possibility exists that there could be life, out there, that defies logic and imagination.

Very informative "hub" Well written and backed up.

Thanks! :-)


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