NASA scientists say evidence of life beyond Earth will be found within 20 years.

What is the best evidence of life elsewhere in the universe, according to Forbes magazine? The question first appeared on the knowledge-sharing site Quora, where NASA coach and flight controller Robert A. Robert Frost replied.
follows Frost's reply: "I don't know if there is any evidence of life on other planets."
, however, I think there is starting to be more and more evidence that life-supporting environments once existed beyond Earth, and perhaps they still exist today.
this whole topic is very challenging because we have to first define a term for which our perspective was once very narrow.
life is? If life is something that breeds, then a mule is life? If life is something that can grow, then crystal is a kind of life? If we agree on what makes a thing "life", does that mean that all objects with these characteristics will be considered similar to each other? In fact, for a long time, our full understanding of life was based only on our observations of life formed on Earth.
observations, we have come to the conclusion that life depends on carbon and water.
we infer that if we can find water and complex carbon-based molecules, then life may exist.
this understanding may be short-sighted, and some lives may not require water or carbon.
knowledge tells us why life is more likely to be based on carbon than on other elements.
carbon atoms are light in mass and have the most abundant types of compounds, with four price electrons and a stable structure of 8 electrons at the outerst layer.
This means that carbon atoms can form four pairs of co-price bonds, while nitrogen (on the right side of carbon in the periodic table of elements) can form three pairs of co-price bonds, and oxygen (on the right side of nitrogen in the periodic table of elements) can form two pairs of co-price bonds.
carbon atoms can also form double bonds, thus forming stable (but not stable to the molecular can not be changed), complex, branched molecules.
means that carbon is a lighter and compound-rich element that can form very complex and elastic molecules.
life is complex, and the survival of life requires some elasticity.
water is also almost seen as a prerequisite for the existence of life.
is a general-purpose solvent that dissolves many substances and plays a very important role in transporting substances in and out of living cells.
, when we look for life, we look first and foremost for complex carbon molecules, water, and temperatures that allow water to exist in liquid form.
just three months ago, NASA announced that it had observed flowing water on Mars.
researchers study images sent back by the Mars Reconnaissance Orbiter and discover grooves formed by the flow of salty liquid water on Mars.
four months ago, other researchers published an article on the formation of late chloride salts in the geological history of Mars, deposited in the region they studied, a lake on Mars that existed 3.6 billion years ago.
3.6 billion years ago during the Archean period, when it was thought that the earth's primary nuclear life was evolving.
Four months ago, another group of researchers published a paper that concluded that early in life (about 4 billion years ago), Mars had water that could cover the entire surface and reach at least 137 meters deep, based on studies of atmospheric water and thorium atoms (the isotopes of hydrogen, also known as heavy hydrogen).
if Mars had had liquid water for hundreds of millions of years, life would certainly have appeared on Mars, even if it was only a short period of geological history.
NASA probes, such as Cassini and Dawn, not only send us stunning images of the solar system's objects, but they also provide data on how common water is in the solar system.
It is believed that Jupiter's moons Ganymede, Callisto and Saturn's moons Mimas, Enceladus and Titan are all believed to exist in the subsurfed saltwater ocean.
neptar's moon, Triton, may also have an underground ocean.
just a few months ago, NASA's New Horizons probe sent back images showing frozen water on Pluto.
September, icarus published a paper on the possible role of comet influences in the evolution of life through impact experiments.
comet not only provides a lot of water for Earth-like planets, but the paper suggests that comet influences play a role in chemical evolution by providing linear peptides.
search for exoplanets also found evidence that Earth is not the only planet with life.
so far, more than 30 potentially life-friendly exoplanets have been found in other "solar systems."
people are becoming more optimistic in their search for life beyond Earth.
Recently, Ellen Stofan, NASA's chief scientist, said, "I believe we will find strong signs of life beyond Earth in the next 10 years, and I believe we will find clear evidence in the next 20 to 30 years."
know where to look, and we know how to look.
most of the time, we have the technology we need, and we're deploying it.
" Source: NetEase Technology