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Are Aliens Living Among Us?
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."
We ARE the Aliens!
There is no "I disagree" mod for a reason. Flamebait, Troll, and Overrated are not substitutes.
Here we have candidate #1: the home-grown favorite, familiar with the local chemistry, which has to propagate a maximum of 13,000 miles to cover every last spot on the globe, a jaunt that is relatively well protected from cosmic rays.
And here is candidate #2: the extraterestrial, which has to make a journey of at least 10^13 miles ( and probably one or two orders of magnitude more to give it a reasonable chance of existing ) through interstellar space, subject to cosmic rays. It has to travel fast enough to get here before the sun goes nova, yet enter the atmoshere at a slow enough speed to avoid burning up. And if it gets here, it has to adjust to a foreign chemistry, and it has to avoid being eaten by all the decendants of #1.
Those are phenomonal odds in favor of #1.
Sure, Hollywood loves to portray aliens as weird, mostly very ugly and very different, meanwhile, I think that actually real aliens are more likely to be quite similar to terrestrial life. After all, we evolved into these forms as a matter of effectiveness and survival. We reflect our conditions more than I think we understand. Therefore, given that physics is physics no matter where in the universe you are, I think people will look like people, horses like horses, fish like fish and so on ...
...
of course, more highly evolved beings likely have more style too
Words to men, as air to birds.
"In recent years scientists have begun to view the existence of life outside of our solar system as ever-more likely"
Oh yeah, I'm sure we all agree with that statement!
After 50 years of listening and looking we have, let's see, ONE suspicious signal that never repeated. Well if you consider that good reason for belief I'm not so sure why so many of you have trouble believing in God.... Having worked with several groups that are committed (and some should be) to the search of ET I'm less convinced than ever. Twenty years ago I was certain, now, not so much....
It's a compelling idea, but what metric would be used to determine if a form of life arose independently? Wouldn't this suffer from the same problem as proving "Intelligent Design" - there is no metric for determining whether something is too complex to have arisen naturally, or too different to by related to known lifeforms. From TFA itself, life as we know it has been found everywhere on the globe, in radically different conditions than ours, which to me suggests that the related lifeforms on earth not only come in a huge variety of forms, but also will probably dominate any system they are in, including the hardest-to-reach ones that we can think of.
It raises an interesting question, however: if life can start, then it can have started more than once. In terms of probability, does this also mean that is has probably started more than once? And if life can start and stop, then does this also mean that life has probably started and stopped?
FTFA:
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.
And:
On the other hand, an organism that employed the same suite of nucleotides and amino acids as known life-forms but merely used a different genetic code for specifying amino acids would not provide strong evidence for an independent origin, because the differences could probably be explained by evolutionary drift.
I think that people (Hello, ID'ers!) sometimes underestimate or misunderstand the power of allelic drift. Our world has incredibly diverse and interesting life forms. What may seem bizarre and "alien" on the surface is often simply the effect of random chance.
it's also amazing how different forms of life can be reinvented
whales reinvented what fish do. bats reinvented what birds do
you can go down into deeper and deeper levels of reinvention of life processes too. for example, horseshoe crabs don't have iron-based red blood, they have copper-based blue blood. go deeper than that: there are bacteria that have completely reinvented photosynthesis from scratch according to an alternative methodology
of course the basest differences this article talks about is exotic, alternative forms of energy in superhot environments, superacid environments, weird chemical/ metal concentrations, etc. by necessity then, these animals have very exotic and bizarre biochemistry, but tehy are still in our family tree, because of the way they store their genes
so the deepest alternatives to life as we know it is to find some bugger somewhere who stores its genes in ways other than dna/ rna
find that bugger on earth, win the nobel prize
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
Bacterial infection of lunar landing sites is a serious concern. Here, read this.
Here's an excerpt:
I always thought the most significant thing that we ever found on the whole goddamn Moon was that little bacteria who came back and lived and nobody ever said shit about it. -- Pete Conrad On April 20, 1967, the unmanned lunar lander Surveyor 3 landed near Oceanus Procellarum on the surface of the moon. One of the things aboard was a television camera. Two-and-a-half years later, on November 20, 1969, Apollo 12 astronauts Pete Conrad and Alan L. Bean recovered the camera. When NASA scientists examined it back on Earth they were surprised to find specimens of Streptococcus mitis that were still alive. Because of the precautions the astronauts had taken, NASA could be sure that the germs were inside the camera when it was retrieved, so they must have been there before the Surveyor 3 was launched. These bacteria had survived for 31 months in the vacuum of the moon's atmosphere. Perhaps NASA shouldn't have been surprised, because there are other bacteria that thrive under near-vacuum pressure on the earth today. Anyway, we now know that the vacuum of space is not a fatal problem for bacteria.Weaselmancer
rediculous.
this does not mean that abiogenesis can occur under such conditions.
exactly. It seems that life is very difficult to get started, even though once it does start it's very tenacious and can survive anywhere. In The Blind Watchmaker Dawkins suggests that running water and clay crystals may be some of the things that are required. In other words, you have organic chemicals laying about (actually, falling from the sky due to comet bombardment) and then being eroded by water. As they travel downstream they are constrained and shaped by crystals. 99.9% of the time, you get nothing. But perhaps once every million years, this results in a molecule that can copy itself being deposited into the shallow sea at the mouth of the stream.
But here's the catch: once that happens, the newly created life starts working its way back upstream, devouring all the raw materials and thus ensuring the process cannot be repeated.
So you make one good point: genesis can only occur under specific circumstances that no longer exist. And I would just add to that this additional point: once it does occur, life eats all the stuff that could be used to make more life.
well at least one, and she(it?) released the following material
1993 Debut
1995 Post
1996 Telegram
1997 Homogenic
2000 Selmasongs
2001 Vespertine
2004 Medúlla
2005 Drawing Restraint 9
2007 Volta
This is almost a text book example of the scientific method isn't it? Some one has a theory "Life is very likely to arise on any Earth-like planet." You can test this and prove it right or wrong by observation. All you need are a large number of earth-like planets you lok at each one and see if there is life. OK darn we can't test this theory. So we have a usles untestable theory. Oe so we thought for for year it was untestable.
What they are saying here, is that if life is likely then maybe here on Earth it started, was wiped out, started again, wiped out again and then we are the product of the 3rd or 100th try. Each of the others being wiped out by some natural disaster like a comet impact or whatever. So here finally is a way to test the theory that life is "likely" if we can show that it happen not once but many times on Earth then it was not a one in a trillion chance but a certainty.
To prove this they only need to find one microbe that is not decedent from the same common ancestor is we are. The microbe does not even have to be living. A fossil would be as good if it could be shown not to share an common ancestor with us.
The odd thing is that there could be 100's of these right in plain sight and we'd never know it and even if we did find it how can we be sure.
Sounds like your country has the same problem America does.
The problem isn't with "uninvited". Everyone is uninvited in the eyes of someone.
Our issue is with "illegal". There is a difference.
Sorry you feel that way, but I have to ask, what country you're referring to and by your affiliation with that country, what gives you the right to speak for the rest of the world?
As bad as America is, it seems everyone is still trying to live here. Can the same be said for your country?