Alien Intelligence

Umbran · Jun 30, 2015

tomBitonti said:
So ... here's a question ... to try to tie this back a bit: Is there a way for a species to cross interstellar space without evolving intelligence?

I suppose space borne spores thrown up by meteorite impacts is a possibility (maybe a very slight one). But anything else?

Hm. Usually, we assume that life must evolve on a planetary body, because that's the only place where we have matter dense enough, and enough warmth. The basic problem is getting it out of the gravity of the planet after that. Even if you could imagine a system evolving to launch something into space, the energy required to leave a planet is very large. The energy required to leave a solar system is even larger. What you ask is difficult.

But then I am reminded of Gregory Benford's book, "Heart of the Comet", in which researchers land on a comet, and find life. Not *intelligent* life, but something more like fungus. The heat of their station throws the growth patterns of this deep-space-cold adapted life into far overdrive, and wackiness ensues.

If you can get life out into the Oort cloud of the star, then maybe some random gravitational interactions with a passing star might break a thing loose and wandering.

Dannyalcatraz · Jun 30, 2015

Something like a tardigrade might be able to hop planets under extremely long odds, too.

Umbran · Jun 30, 2015

Dannyalcatraz said:
Something like a tardigrade might be able to hop planets under extremely long odds, too.

Yeah, but hopping planets is not hopping stars.

Dannyalcatraz · Jun 30, 2015

Clearly not, but if there is a terrestrial critter that shows how it could be done, it would be the tardigrade. Tough little bastards.

Cleon · Jun 30, 2015

Umbran said:
Many folks seem to think the maximum size is limited by strength/weight of materials of the exoskeleton. My understanding is that oxygen transfer is the more limiting factor - arthropods don't have lungs, and there are limits to how much oxygen they can get into their systems.

That's not quite true. While none have lungs that work like vertebrates do, many chelicerates have "book lungs" and some crabs have "branchiostegal lungs". They tend not to be as good as vertebrate lungs though, being generally less efficient and more prone to water-loss.

Furthermore, if the arthropod gets its oxygen from water rather than air that hardly matters, since it'll use gills to breathe - and arthropods can grow to impressive sizes in water. I believe the current record is about 10 feet long for an extinct Eurypterid.

However, I don't see why the above matters that much. The aforementioned "30-foot alien insect" would only resemble an insect. There's no reason its circulatory and skeletal anatomy would include the limitations that prevent terrestrial arthropods reaching dinosaur size.

MechaPilot · Jun 30, 2015

Mustrum_Ridcully said:
Yeah yeah, the old spiel about how we are not really all that smart and aliens would avoid us.

You have me wrong. I'm not saying intelligent aliens would avoid us because we're not smart. It's just, as a species, we are currently horrible people despite the fact that we are smart enough to know better. We have the intelligence to be better people, we just don't have the motivation. Maybe that will change, or maybe some other life form will find the radioactive ruin of our civilization.

tomBitonti · Jun 30, 2015

Cleon said:
However, I don't see why the above matters that much. The aforementioned "30-foot alien insect" would only resemble an insect. There's no reason its circulatory and skeletal anatomy would include the limitations that prevent terrestrial arthropods reaching dinosaur size.

But, that sidesteps the point: A creature which has the common physical structure of an insect can't survive as a land dwelling terrestrial organism if enlarged to be 30' tall. Basic physics and limits on material properties prevent it.

The question is whether there are materials with the necessary physical properties to endure a journey to a nearby star, including deceleration, and remain functional.

One could ask a similar question as a sociology question: Could a generation ship actually keep a functioning and healthy society, for thousands of years?

I don't think we have an answer to either question.

Thx!

TomB

Umbran · Jun 30, 2015

Bullgrit said:
Isn't that one theory on how life started (came to) on Earth?

I wanted to go back to this for a moment...

To answer the question: Yes, and it is possible that life got here that way, but....

...that theory doesn't answer any hard questions, and adds several. You still need life starting from scratch *somewhere*. I don't see how starting somewhere else and travelling across interstellar distances is somehow more likely than just starting here.

As usual, passing the buck doesn't generally solve anything

Dannyalcatraz · Jul 1, 2015

tomBitonti said:
But, that sidesteps the point: A creature which has the common physical structure of an insect can't survive as a land dwelling terrestrial organism if enlarged to be 30' tall. Basic physics and limits on material properties prevent it.

What I think his point was: just because it looks like a bug, doesn't mean it is made like a bug. It could have an exoskeleton made of something much lighter and stronger than chitin, for instance. Its musculature could be stronger per pound. Instead of oxygen, it may "breathe" something more plentiful in our atmosphere.

Umbran · Jul 1, 2015

Dannyalcatraz said:
What I think his point was: just because it looks like a bug, doesn't mean it is made like a bug.

In the thing I was responding to, it wasn't a 30' tall thing that *looks* like a bug. It was a 30' tall insect. As in, made like a bug, built on the terrestrial insect plan: Chitin for exoskeleton, no endoskeleton, insectoid breathing apparatus, and so on. Tom and I were agreeing that such wasn't possible, and quibbling over what counted as "theoretically" impossible vs "practically" impossible.

Can we imagine a thing that looks an awful lot like an insect,t hat is 30' tall? Sure. But that wasn't the point of the discussion at that time.

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