Why do we think that aliens must live on a planet with water?

Maybe it is Earth-beings who need water. What if other forms of life depend on something other than water?

Liquid has some properties that are very favorable for life. It flows and fills up available spaces, carrying potential nutrients along with it. Yet it is substantial enough to support matter while allowing it to move from one location to another. Solids cannot do that, and gas is not so good in the matter support department. So liquid is a good thing. What is the most common liquid in the universe? Probably water. It is possible that alien life could exist on the surface of a place like Titan, where lakes and rivers of methane flow freely. Perhaps we will find it there eventually (so far, we have not seen any obvious indications that there is life on Titan). But I am willing to wager that if we find a place that has significant amounts of liquid water in a temperate climate, we will also find life. It’s really more a statement of the likelihood of finding life in such a place than an absolute criterion.

While it is true that life could be based on something other than the carbon/oxygen/water basis we have for life here on Earth, it is the only form of life we have any knowledge of, so perhaps it is a bit easier to use those criteria we know and understand, at least in part. The researchers don’t attribute the possibility of life solely to water and oxygen, but as I said above, it is the life system we best understand (or the only one we understand). While there are variations that might be possible, that is conjecture. There have been numbers of science fiction stories with other life bases, but we KNOW our own. Watching Alien movies and reading sci-fi is good entertainment, and may be a basis for some conjecture, but that’s about it. I agree that if hydrogen and oxygen are present in an environment, there could be water. Again, though, water vapor, or ice don’t directly support life as we understand it — our life forms need liquid water. Knowing hydrogen and oxygen are present could mean water, but phase state is important too. Since the landers have taken Mars’ temperature, we have a lot less hope there, and Venus is way too hot, as far as we can surmise.

Well, the only life we have found is on this planet and every single living thing needs water to survive, including virus whether or not you consider them &quot:living&quot: or not. Until we first find life on other planets we must assume that all life needs water and is made up of Carbon and needs sunlight. You must always follow what is given. Is all life going to be made up of water and carbon? Probably not, but until we prove otherwise that is what we should believe. Have you heard of the rivers and lakes of liquid methane on the moon Titan’s surface? Now that’s cool. Maybe there’s some bacteria or something of the sort thriving in the freezing temperatures, consuming the liquid methane.

The most common element in the Universe is Hydrogen.
The very basic elements are helium, carbon and oxygen, and exist also in very large quantities.
H and O make water.
To create life, we need complex molecules, and the first element that allows many different forms of molecules is Carbon (followed later by Silicon). All life on this planet is carbon-based.
For these molecules to form, they need a liquid environment in which they can &quot:move around&quot:. The easiest &quot:liquid&quot: and the most common is &quot:water&quot:.
The normal process of evolution (and the most probable to happen) is then carbon-based life form created in water.
A silicon life-form is also possible, but since heavier and rarer than carbon, a &quot:denser&quot: liquid would be needed, leading to a more complex liquid, reducing the chances of the appearence of this life form.
It is then more logical, in our search for alien life, to look FIRST for a planet with liquid water.

As others have said, the search right now is for life as we know it. I suppose any form of life would need some sort of a solvent to carry nutrients to different parts of the organism. That fluid would probably be sort of inactive so it wouldn’t react with what it was supposed to transport. On Earth, water fills the bill.

I wonder how we would recognize life as we don’t know it, perhaps life based on gold instead of carbon.

All life as we know it requires water. Therefore looking at planets with water on is a starting point for our search, and gives us a better chance of recognising something as life when we see it. Other forms of life will be looked for later.

Consider the Earth as a pin head bobbing up and down in the Indian Ocean – We assume everything must need the same requirements as us… It’s quite ridiculous to assume that all life is dependent on our parameters?

One hundred years ago, the majority of residential homes did not have electricity, telephones or television to access the media (Something we now take for granted – with probably zillions of channels to choose from!!)

Man will kill himself long before we develop the means to communicate with other races, mankind is just a passing race, as soon as we developed atom bombs – we dropped them on our own species.. (Lets flex a bit a muscle!!)

How soon until the first nuke is deployed?? The first one will trigger a massive worldwide response..hence, the end of mankind.

The next rulers of the planet will be digging our bones up thousands of years after wards, we will go down in history as the most brain dead creatures to have ever walked the Earth since the dinosaurs…

Aliens DO live on planets without water. They are on the back side of the moon. Here is proof:


What you should ask is whether aliens are INDIGENOUS to a planet without water. NASA has found evidence on some of our solar system’s moons that liquids such as ammonia, methane, and formamide could also be the building blocks for life. For instance, during the Cassini mission, they found that it is actually raining methane on one of Saturns’ moons called Titan. Here is what the surface of Titan looks like:


It is always possible that that is the case. However, if we wish to search for life, we need a starting point, and so far, the starting point is one that depends on water.

So far, every organism discovered on Earth needs water, for inherent survival, or else for transport (in the case of viruses).

I agree 100% !!!!!!!!!!!!!
why does other planets and universes have to follow our lead ?
that’s not very open minded, but than again, science is not very open minded to alien life to begin with, we can assume here on earth that we deal not only with the weired but other dimensional phenomena here on earth, so who to say what we dont see on other planets suggest that its lifeless, as long as the possibilities of other demensions exist, then there could be life on mars and elsewhere.

Leave a Reply

Your email address will not be published. Required fields are marked *