Are Aliens Living Among Us? 350
pickens writes "In recent years scientists have begun to view the existence of life outside of our solar system as ever-more likely. If life does emerge readily under terrestrial conditions, then perhaps it formed many times on our home planet. To pursue this tantalizing possibility, scientists have begun searching deserts, lakes and caverns for evidence of earth-bound 'alien' life-forms, organisms that would differ fundamentally from all known living creatures because they arose independently. Microbes have already been found inhabiting extreme environments ranging from scalding volcanic vents to the dry valleys of Antarctica. Other so-called extremophiles can survive in salt-saturated lakes, highly acidic mine tailings contaminated with metals, and the waste pools of nuclear reactors. Although 'alien' microbes might look like ordinary bacteria, their biochemistry could involve exotic amino acids or different elemental building blocks so researchers are devising tests to identify exotic microbes. If shadow life is confined to the microbial realm, it is entirely possible that scientists have overlooked it."
ALFs? (Score:5, Insightful)
I think we have enough problems with ourselves, to worry about aliens living among us. As a matter of fact, what sort of superiour intelligence, which could get here, would use earth as anything other than their own Botany Bay Colony?
Spiders (Score:4, Insightful)
Have to be compelling (Score:3, Insightful)
Possible, but unlikely (Score:5, Insightful)
Living things are, in general, very competitive, and very effective competitors. Otherwise, they wouldn't still be here. So the odds that a new abiogenesis event, if one occurred, would produce a lifeform that would actually be viable in the face of a billion years of evolution by the competition are, I think, remote.
Also, while living things may thrive under extreme conditions (for example, in a bath of deadly oxygen gas) this does not mean that abiogenesis can occur under such conditions.
Finally, while it is true that many lab techniques are specific to detecting conventional terrestrial life, others are not. So, unless this non-conventional life is *restricted* to some remote environment - which conventional life certainly is not, so this again seems unlikely - we would be expected to have seen it.
There are some exotic coincidences which might allow for this to be true - maybe this exotic life looks just like a bacterium under the microscope, but for whatever reason cannot be cultured at all. Maybe it can't live on sugar - maybe it requires some other exotic organic nutrient which is found out in the wild but no-one has thought to add to culture medium. All possible, but also all unlikely.
Nonetheless, problems of detection of this kind remain a serious and useful direction for inquiry, in preparation for serious efforts to locate alien life on other worlds, where we will need a wide array of avenues for detection to allow for a completely-unknown level of chemical diversity.
Re:Possibility of life..... (Score:3, Insightful)
At the same time, the universe is really, really big. The odds are very good that the right combination of environment and events occurred many, many times. The odds just happen to be very bad that it happened a second time anywhere near our arm of our galaxy.
Re:Possibility of life..... (Score:4, Insightful)
I think the probability of detecting intelligent life is rather low using SETI (though worth a shot). However, the possibility that life in some form exists out there is, I think, very high.
Re:Possibility of life..... (Score:2, Insightful)
I think you have to consider the existence of alien life as opposed to intelligent alien life as two entirely different questions. If you add up all the kinds of life on Earth and compare that number with anything remotely capable of thought, the ratio is pretty outrageous. For the sake of scientific accuracy, let's call it a gazillion to one.
Life might be common. Sentient life, not so much. Sentient life that communicates in a way we recognize and can detect across interstellar distances during the eye-blink of time we've actually been looking...let's not get too discouraged yet.
If you've worked with "several groups" investigating the question, I'm surprised you wouldn't automatically make such a distinction.
Re:Real aliens aren't from hollywood! (Score:3, Insightful)
I'm with you that we are product of our environment. But you are ignoring the implications a tiny terrestrial change would have on ALL terrestrial life.
For instance, assume the earth contained
Heck, even within our earth's periods we've seen incredibly different paths of evolution occur. What happened to the dinosaurs? Well they were here, new conditions arose, and suddenly new phenotypes are preferred. They evolved but are no longer dominant due to shifting and somewhat unpredictable conditions.
Basically I'd agree with you if Earth 2 existed and had a COMPLETE MIRROR IMAGE of our planet's history. Then we could be assured that all the variables are in sync. But what kind of odds would you give that?
Aliens could be of almost any imaginable form & traits because they could arise in almost any imaginable conditions.
Re:Possibility of life..... (Score:3, Insightful)
Life is a set that is likely to be considerably larger than the set of advanced civilizations.
this has already been shown! (Score:3, Insightful)
Re:Spiders (Score:5, Insightful)
PS: Yea, its biology might be different so harder to digest edible but when you eat a poisonous plant it's still dead.
Re:Have to be compelling (Score:5, Insightful)
Finding it means that life arose here twice (at least) and would a be revolutionary discovery. If life is common in the universe and likely to arise on any Earth-like planet then why would it not arise twice on any Earth-like planet? Or three times or 100? Science is about asking questions and this is a good question, good because it is both interesting and (maybe) possible to answer by direct observation.