Why do scientist think that if there's water in a another planet there will be other lifeforms?

Question

I mean,there are not from Earth,so why must the live if there's water around.Why can't it be another substance

Answer 1

Well as we know it there can not be life without water. I am not saying it is not possible that other life forms in some far far galaxy have not come to life without the need for water, but using our planet as a guide since this one we know for sure has life, water is an important factor for the life here to exist so we assume that for all others

Answer 2

It could be another substance, Sulphates or some strange variant of silicates or some strange cocktail of ammoniates or hydrocarbons or something, might make for an even better medium/solution in which life can form.

However, we don't know any of those other methods, we know only about the stuff on Earth really well , and until we bring samples back from Titan or some Martian thermal mudpool or the presumed oceans of Europa, we don't know.

The thinking goes like this.

Barring a monolith, Earth developed life under the conditions of having a relatively moderated climate (no hard radiation or strong extrasolar gamma ray bursts), there was alot of water, with some moderate amount geothermal heating with salts and other biochemcials add some time and you get primitive life-forms actually pretty quickly.

So it's possible we will get out into the solar system and find life on every moon or planet we search.

The next better question is whether it's exactly the same, if the life has a genetic composition nearly identical to ours, then its more likely that either originated on Earth and was spread by impacts to other worlds, OR that life came from space elsewhere by virtue of hitching a ride on a comet or something.

If the lifeforms we find on the other moons or planets is found
and it is signficantly different in composition from life on Earth then that means that life can develop in a variety of environments, and that the universe is widely populated with life, because you don't need some "Goldilocks" planet like Earth, but could get life on Europa or Titan.

It also bumps up the possibility of intelligent life, because it would mean that given 1/2 a chance life will arise on a world and that means every "Goldilocks" planet , would have an increased chance of having life as well.

Answer 3

>Why do scientist think that if there's water in a another planet there will be other lifeforms?

Well, considering that life on Earth developed very soon after the conditions were right for life, it seems that places that can support life have a high chance of developing it, so if some other object has liquid water on it then presumably life could exist there, in which case there's a fairly good chance that it DOES exist there.

>I mean,there are not from Earth,so why must the live if there's water around.Why can't it be another substance

Water is a very good solvent, which is why terrestrial life forms use it in their body chemistries. There ARE other good solvents that could concievably support life as well; the most likely example is ammonia (NH3), which exists as a liquid under colder temperatures than water and could possibly support life in cold environments (such as on the surface of Saturn's moon Titan). However it seems that water is still better than ammonia, and additionally it is liquid at higher temperatures which would support faster chemical processes, so there is little doubt that water is the most likely solvent for alien biochemistries.

Answer 4

Water is one of the most abundant compounds around. It is liquid, solid and vapor in a convenient temperature and pressure range for organic reactions to take place. It is a very good media for moving nutrients around, it holds temperature well, protects against radiation and is not overly reactive. So, it is reasonable to think that when liquid water is present, the conditions for life are favorable.

There seems to be some good science coming through that says life could potentially form in other media. So you're right - it doesn't necessarily have to be water-based. Water is just the apparent best choice to work with, and we have proof it works.

It's easier to go looking for something you know than for something entirely different. Probably someday we will find life based differently than we currently understand. Probably after we have found several examples of more "ordinary" life.

Answer 5

Life depends on chemicals forming complex interactive and replicable molecules. Biochemists have worked toward finding something other than carbon based chains with that behavior. Silicon is a possibility, but not as promising as carbon. Either way, it requires water as a neutral solution in which interactions can occur.

Answer 6

because water is the main element that every living thing needs to stay alive! If there's no water on a planet that planet wouldn't be able to support life, because everything would dehydrate. Scientist don't think if there's water there WILL be life, they just believe that it might be able to SUPPORT life.

Answer 7

Could be...

However, these folks know what made life forms begin here on Earth, so they reason, that must be what would make life forms begin somewhere else. It could be entirely the wrong idea, but it is the one they are going with for now.

Answer 8

Water IS the basic source of life !

Every living creature, plant or animal or bug is made of a significant percentage of water.

There is no life without water. It is God's gift to us.

Answer 9

because on earth life is thought to have developed in the waters that were on the earth millions of years ago

Answer 10

eh