Aliens - Do they exist?

[ur-bane]

I have nudged, just a very very subtle hint here and there....

[Prebe]

Gimme a break! lemme just read the posts guys!

[Avatar]

Told you this would happen, scientist-type.

--A

[ur-bane]

Yeah, and the scientist type's observation skills are less than satisfactory, for the scientist type missed that all those prodding posts were before he knew about our request for him to join the discussion.

[Prebe]

EDIT: Giggle! NOT coherent. I pasted stuff for my Cail discussion in there. Sorry!

"Rather, the susceptibility of cattle to these toxins seems simply to be an unfortunate coincidence of a toxin working across a large evolutionary distance," Chyba writes.

True. BUT, there is a major difference between general toxicity and specific pathogenicity. Specific pathogenicity springs from a co-evolution (or rather an evolutionary arms-race) between species. This is the scary kind. Such a threat is more than unlikely to come from alien lifeforms.

The non specific pathogenicity or toxicity in some cases is more likely, but still less likely, than an organism from a remote and inaccessible place on earth posing a similar threat.

If carbon based, and even DNA based life is the order of the day (which I consider likely) the threat would be bigger, but still unlikely.

Am I being coherent?

[ur-bane]

(EDIT)
Doh! I saw your edit!

So, even if a threat wasn't immediate, if an alien microbe managed to survive on earth, it could adapt and become a threat, no?

[Prebe]

I conceive this highly unlikely, as survival of a microbe would require a suitable habitat to begin with. Pathogenic organisms are as a general rule of thumb not able to survive for long without their host. Mechanisms for specific pathogenicity and actual infection are nearly always far more intricate than mechanisms of toxicity.

And then there is of course the primary and secondary immune system in animals, that the alien microbes could never have anticipated. While antibodys evolve (that's what they do) in the space of days, a new microbe would need ideal conditions and a long time to evolve into anything even remotely threatening.

Edit: I knew I wouldn't be fast enough for you guys

[ur-bane]

But that's not true in all cases.
Take the canine parvovirus, for example.
It can live indefinitely without a host to sustain it. It lies dormant until an unknowing host cmoes along, then it attacks the host.

[Prebe]

Many viruses have that ability. But it is called canine parvovirus because it attacs canines. Furthermore, to evolve, an organism must by definition be able to multiply. No habitat (host), no multiplication and thus no evolution.

[ur-bane]

Given the rate of multiplication of virus and bacteria, couldn't that happen in a short period of time? So even if a virus lay dormant for a while, once a host was infected, wouldn't that virus multiply exponentially within that host?

And although the alien virus may not be carbon based, isn't it possible that something in our bodies could be fuel for that virus, allowing reproduction, and therefore adaptation?

[Prebe]

Given the rate of multiplication of virus and bacteria, couldn't that happen in a short period of time? So even if a virus lay dormant for a while, once a host was infected, wouldn't that virus multiply exponentially within that host?

Shame on you for using my own words against me

However, the mechanisms by which a virus infects and multiplies is extremely intricate, and needs a very well deffined cellular envelope and host metabolism (DNA-replication for example). So I still think it unlikely that an alien virus (assuming such a thing existed) would ever be able to infect an animal.

But the evolution could be fast, that much is true. But it would probably still require a large number of infected individuals.

[Cail]

Come on, we've all seen The Thing. Any alien contact we have will end badly for us.

[Prebe]

Especially if they are the type that make our severed heads sprout legs

[Avatar]

Thanks Prebe. Makes sense to me. Theoretically possible, but highly improbable.

--A

[Zahir]

Well, this is JMHO, but...

The universe is really really huge. And from what we can tell, planets should be really common (a quasar in our vicinity has one!). Yet we don't seem to see anyone else.

So, while complex life is an open question, it seems technological civilizations must at the very most be extremely rare right now. Maybe we are among the very first to arise. Perhaps the nearest like-minded group are so different from us there's really no reason or way for us to interact? All our neighbors might be extinct or reclusive or extremely weird or have transcended to some other form of existence. That is if they even exist and have gotten past the stone age yet.

[ur-bane]

Robots are going to be doing all the exporing anyway,imho.
I see an intergalactic internet at best.
Still, I'd enjoy that.

Imagine Watch members from mars reading the Chrons

Sorry---I just caught this today!
Imagine that, indeed.
We'd have The Martian Chronicles of Thomas Covenant the Unbeliever!

[Cheval]

We'd have The Martian Chronicles of Thomas Covenant the Unbeliever!

The Plains of Ra would take on a whole new meaning too, I guess.
(taken, in part, from "The Unbeliever's Guide To The Galaxy")

[Vraith]

Just had to resurrect a dead thread about life for this.
Possibilities for alien life have been jumping a lot lately...
The number of planets out there...higher than many expected.
[[I think I recall a thing suggesting there might be twice as many stars as we thought, too...which increases things even more]]
The number in "Goldilocks" zone for Earth-ish flavors...much higher than
expected.
We've got a number of indications now that the creation/growth of complex organics is common/natural. It's not only NOT a violation of entropy, it appears to be a RESULT of entropy.
We've known for a long time that life is made of very common elements.
And that those drift around in cold clouds and space.
And NOW:

Astronomers have known for some time that cold, dark interstellar clouds are very efficient factories for complex organic molecules
[[snip]]
Until now, it has remained unclear, however, if these same complex organic molecules commonly form and survive in the energetic environment of a newly forming solar system, where shocks and radiation can easily break chemical bonds.
[[snip]]
astronomers can see from the latest observations that these molecules not only survive, but flourish.
Importantly, the molecules ALMA detected are much more abundant than would be found in interstellar clouds.
[[snip]]
protoplanetary discs are very efficient at forming complex organic molecules and that they are able to form them on relatively short timescales [3].

So, this makes me more sure than ever that there is alien life.
It doesn't much alter my opinion that there was and will be other intelligent life---nor the fairly low, but non-zero odds that we will ever talk to them. [my wish level for such talk is still sky high, though].

www.sciencedaily.com/releases/2015/04/150408131422.htm

[Hashi Lebwohl]

There was one NASA person just last week saying we would find evidence of non-terrestrial life by 2020. I hope we do find such evidence relatively quickly so that our collective reality shift can start to take place.

[peter]

I wonder if [given the very real problems we have had in nailing down how life actually did begin here on earth] if it not might still turn out that in fact we are the aliens that we constantly seek and talk of. Wouldn't there be something cool about a re-meeting up with the distant ancestors that [in such a scenario] seeded the cooling earth with life. Perhaps they already knew that the 'omega point' of intelligent self-awareness would naturally occur of it's own volition if you just stuck some DNA in the oven and left it to bake for 5 billion years! Surely these would be the only extra-terrestrials we could trust enough to embark on a dialogue with and hope [still perhaps a little over optimistically] that we wern't going to finish up strapped to the alien vivisectionist gurney .