Slashdot Mirror
NASA Asks: Will We Know Life When We See It? (nasa.gov)
In the last decade, we have discovered thousands of planets outside our solar system and have learned that rocky, temperate worlds are numerous in our galaxy. The next step will involve asking even bigger questions. Could some of these planets host life? And if so, asks NASA, will we be able to recognize life elsewhere if we see it? From a blog post on NASA's website: A group of leading researchers in astronomy, biology and geology has come together under NASA's Nexus for Exoplanet System Science, or NExSS, to take stock of our knowledge in the search for life on distant planets and to lay the groundwork for moving the related sciences forward.
"We're moving from theorizing about life elsewhere in our galaxy to a robust science that will eventually give us the answer we seek to that profound question: Are we alone?" said Martin Still, an exoplanet scientist at NASA Headquarters, Washington. In a set of five review papers published last week in the scientific journal Astrobiology, NExSS scientists took an inventory of the most promising signs of life, called biosignatures. The paper authors include four scientists from NASA's Jet Propulsion Laboratory in Pasadena, California. They considered how to interpret the presence of biosignatures, should we detect them on distant worlds. A primary concern is ensuring the science is strong enough to distinguish a living world from a barren planet masquerading as one.
"We're moving from theorizing about life elsewhere in our galaxy to a robust science that will eventually give us the answer we seek to that profound question: Are we alone?" said Martin Still, an exoplanet scientist at NASA Headquarters, Washington. In a set of five review papers published last week in the scientific journal Astrobiology, NExSS scientists took an inventory of the most promising signs of life, called biosignatures. The paper authors include four scientists from NASA's Jet Propulsion Laboratory in Pasadena, California. They considered how to interpret the presence of biosignatures, should we detect them on distant worlds. A primary concern is ensuring the science is strong enough to distinguish a living world from a barren planet masquerading as one.
The line between life and not-life is already indistinct here on Earth. Viruses? Not-life...quite. Kinda life?
And forget trying to figure out what counts as intelligent life. Trees communicate with an underground fungus network and through signals in the air, can probably feel pain, count and learn, but we're not quite at the point of calling them 'intelligent'. Birds turn out to be incredibly intelligent, but people are still reluctant to admit the level of intellect the birds have, and how deep it may actually go.
What hope do we have of classifying an indistinct gas-being that gets by just fine when we're not around, but immediately decoheres the moment a human passes through them waving their hand in front of their face? Or some sort of super-cooled snow creature with liquid nitrogen in its veins that reacts too slowly for us to even comprehend?
it is possible that life is everywhere, all around us in forms we don't recognize...
There are so many things that could make life unlike ours invisible. Imagine for a second a life form that's brain runs 1 billion times slower or faster than ours. Silly example to make my point: Mount Everest could be a slug, but it moves so slow that we would never know it as anything but a lifeless rock.
Mike @ The Geek Pub. Let's Make Stuff!
My father (who only went to school for seven years, and started working at 14, and isn't precisely highly educated) asked me the other day wether water is a pre-requisite for life. I answered as most do; yes, probably. Without some kind of solvent, reactions and material exchange is slow.
That got me thinking of scales... what if "slow" isn't a problem. What if we encounter beings with metabolism rates which are 100 000 slower or faster than ours? Would we be able to recognize it as life? Which other dimensions could scale so that we wouldn't recognize it? DeGrasse talks about intelligence - would we recognize life that is 100 000 times smarter or dumber than us? Could there be life at extreme temperatures? I don't mean 1000 deg C, I'm talking about life inside stars. There is for sure a thermal and entropy flow - could there be fusion plasma solutions to Maxwell that could make basic building blocks for something life-like? If so, could we ever observe it?
At any rate, it may be material for a star trek episode...
I seem to recall a talk about sulphur-eating archaea in a hydrothermal vent environment in which no evolution has taken place for millions of years, because they've apparently reached an optimal solution (local maximum anyway) in utilizing the resources in the simple and small environment.
Evolution only works (and takes place) if you can still do better. Otherwise, you get the "surprising continuation" aspect of life without the (further) evolution aspect.
Where are we going and why are we in a handbasket?
Just like all physics: we theorise, we predict, we observe.
Predict: by current theory, spectral lines of elements on earth should be "this".
Observe: yep, that seems to be true on earth.
Predict: the universe is pretty boring, same rules everywhere, so spectral lines will be the same everywhere, plus (consistent) red/blue shift because stuff is moving (and we can predict that too, with current theory).
Observe: look at distant objects and what do you see... crikey jingo, it matches the prediction.
Sure you could no doubt dream up an alternative reason why the predictions work that involves exotic "physics" in distant galaxies, but that seems like an unjustified complexification to me.