what conditions are necessary for life on earth?
338534
The same that are needed for suvival in the wild. In order.\n\nUnrestricted breathable air.\nShelter. Temerature protection.\nWater. Drinkable as in no germs and low salt.\nFood. And the ground with which it either grows or feeds the animals we eat.\nGravity.\nThe sun.
941059
There are theories surrounding the possibility of silicon based life.\nHowever, silicon is fairly limited in the number of compounds it can form that could be considered "necessary for life".\n\nCarbon can form with practically anything to form anything.  That is why carbon is considered to be an essential base for all forms of life.
332737
This is interesting question. My opinion is: why not!! Maybe some forms of life that we don't know. There is some life forms even 11 km under the sea, under extremely high pressure. Some kinds of bacteria live without air too. Fish don't use the same air like us, but they are alive. There is so many different forms of life even on planet Earth, so why not on other planets? After all, if we did not see something, don't mean this don't exist!
228093
OMG...this is a very sad question. The reason why gloval warming NEEDS to affect the earth is because without it, we would all DIE. Think about it, what would we do if there was no heat at ANYTIME. We would all die because we would all freeze to death. Besides in order to keep anything alive we need Gloval Warming. The food we eat need it, the water need it, the plants, animals everything and everyone needs it.
817070
Earth suport life - fer beter speling!
449205
Earth is the only place in the universe where life is absolutely known to exist, and some scientists believe that biospheres might be rare. The planet's lifeforms are sometimes said to form a "biosphere". This biosphere is generally believed to have begun evolving about 3.5 billion (3.5×109) years ago.\n\nThe biosphere is divided into a number of biomes, inhabited by broadly similar flora and fauna. On land, biomes are separated primarily by latitude. Terrestrial biomes lying within the Arctic and Antarctic Circles are relatively barren of plant and animal life, while most of the more populous biomes lie near the Equator.\n\nThe Earth consists of several atmospheric, hydrologic, and many geologic layers. Its components are the atmosphere, the hydrosphere, the crust, the mantle, and its core. The biosphere is a tiny layer in this composition and is usually not considered part of the physical layers of the Earth.
267890
The chemistry of a perfect life would be one where all the metabolic processes are well regulated and where the chemical pathways of energy production are not futile, but rather very efficient. This is hard to find. The human body was made to resist changes despite the outside environment and being perfect at a certain time would probably mean there is not external factor that affects calls for homeostasis, which is pretty unlikely.
1044962
It has recently been suggested that life on earth began much earlier than once thought. The earth is around 4.5 billion years old. But life is thought to have started just 500 million years into its existence - not long after it was first able to really support life.
918461
So far, science knows that in every life there is oxygen and protein or amino acid but other constituents are not known yet. Hindus believe that there is a life energy which is a property of Nature that is more vital than the material property as detected by the modern Science.
449284
I think that if carbon was not available when life was being formed, then life would be dependent on something else.  \n\nIf you notice, everything that is essential for our survival, is stuff that was plentiful when life was first forming.  If oxygen wasn't there, then we would not be dependent on it today.  Same with sunlight and water.
53089
To live we need water, and oxygen for oxygen we need trees for trees we need soil there you go!
5565
First you have to define life.   Unfortunately by the standards we use today light and gas cannot be considered lifeforms because they cannot reproduce and carry out other life functions.
1132699
Well.. \nI'm more scientific than religious in this matter. \nThe reason Earth has life is because of the certain climate, temperature, etc. which is perfect for life. \nHowever, there are always news stories about "possible life on mars" and as such. And I believe that for life to form, there needs to be a certain set conditions which allow life to be formed and which support and maintain it. \n\nTherefore,  most definitely there could have been life in other planets, maybe some organisms or something else which is suited to that planet's climate, temp. and etc. It could be that we either can not detect that life on the other planets or the planet is undergoing some sort of climatic change which does not support life due to variant pressures. \n\nDid god stop at Earth-- well, that is a question which is a matter of belief- if we consider god as a positive force which stimulates life- then no, god wouldn't have stopped only on Earth. \n\nSome research even claims that there are other solar systems with other stars (like our Sun) in which a planet is very like Earth- almost same which supports life. \n\nSo, whether life is or not- is a personal decision. I think there is- but as you say, there is no real solid evidence supporting or contradicting existence of life in other planets
966179
In order to survive, animals need air, water, food, and shelter (protection from predators and the environment); plants need air, water, nutrients, and light. \n\nEvery organism has its own way of making sure its basic needs are met.
956514
Hi. I read your other answer. See below. The atmosphere is almost 93,000 000 miles away, so don't worry. Earth is more that just wonderful. It is exceedingly rare in my opinion. Together with the Moon, her oceans, her temperature, her atmospheric environment - all these make for an unusual combination of life supporting qualities. We should cherish this home we have.\n----------------------\n"This is wonderfull idea! Just imagine if could expand the size of our tiny little planet.\n\nOn the downside though, it is believed that the dimensions of earth is perfect for the exixtence of life on it. if we made her any bigger, our atmosphere would be too close to the sun, and earth would fry like a tomato.\n\nJust my opinion."
1170146
There are traditionally only 4 elements - Fire, Water, Earth and Air / Wind. These were believed by the ancient greeks to be the fundemental basis of life. \n\nScientifically, there are not only several elements needed for life to exist but also certain conditions of environment also - the best elemental mix would struggle to form life in the near vacuum of space.\n\nAll known life is carbon based. The other elements needed (depending on environment) would include hydrogen, oxygen, and nitrogen.\n\nIf you are talking about throretical extra terrestrial life, this could be silicon based and have an entirely different chemistry to anything we would recognise.
143137
I think so!\nIf life exists on the top of the large mountain where there is only snow and no oxygen in the air, then life should exist on other planets!\n\nDo you know that, life exists in deep sea where there is no sunlight! If life sunlight to live, how do you explain?\n\nLife also exist in caves very down in earth where no light is present. They are bacteria! They absorbe heat from boiling water, thats how they obtain their energy!\n\nThat may be quite enough to explain how life may exist in extreme conditions and thus beyond planet earth