生命能否以氣態形式存在？

腦洞大開的想法，我們見到的生命其形體大都包含固態的物質，有沒有可能其他星球上的生命以氣態或者液態形式存在，而且具有智慧

科幻小說中對於氣態生命早已有各種各樣豐富的想像了，不過如果要說科學家的看法，可以參考美國國家科學研究委員會編寫的一本書《The Limits of Organic Life in Planetary Systems》，其中有一節就提到了氣態生命：

6.3.1

Life in the Gas Phase
In the gas phase, chemistry is limited to
molecules that are sufficiently volatile under the ambient conditions to
deliver an adequate amount of material to the gas phase at moderate
temperatures. Raising the temperature does not necessarily solve the
problem. Although more molecules enter their gas phases as the
temperature is increased, organic molecules generally cease to be stable
at temperatures in excess of 500 K.
It is conceivable that in the vacuum of
interstellar space, life exists through molecules at high dilution
reacting in the gas phase. Grains have been suggested as a way of
collecting organic species, perhaps with an outer layer that protects
the inner layer from irradiation. The possible disadvantage of this, of
course, is the difficulty in holding together the components of the
interstellar life form. One advantage of such a life form would be that
it need not be encumbered by the lifetime of a planetary system. Indeed,
one can imagine that life in the gas phase might be associated with a
galaxy and its energy flux for nearly the age of the universe.