The Feasibility Of Natural Exoskeletal Hands In Scifi...

[Spacescifi]

Often in science fiction scifi humanoids are either given pointy ears or odd colored skin as their sign to show their alien-ness.

Personally, I favor more practical effects.

Scenario: Like is common, their skin is some odd color, but beyond that their body appears human... only their hands are different.

Instead of soft hands of flesh with endoskeletal bone, they are exoskeletal hands with whatever muscle/tendons working beneath it without bone.

In addition to this, the hands have a small valve hole in the middle of each palm that can open or close.

When open one hand can can squirt an orange liquid 70 feet (if sprayed along an arc path) while the other shoots a blue liquid.

If the liquids come into contact they cause chemical combustion on contact.

Humanoids have a limited reserve of these liquids but generate more daily, especially while sleeping.

Reason: It's a designer humanoid race, designed specifically  to have the ability to start fires without any tools required, which is also useful for self defense obviously besides combat.

 

Main Question: How feasible is this according to physics? I think there is nothing in physics that says such a concept is impossible to exist.

Also how practical would it be? I know exoskeletons are lethargic when molting and cannot be used as actively since they are softer, but according to youtube videos crabs only take about 30 minute to shed their exoskeleton and two days to fully harden up.

With the OP humanoid race, it's only the hands, so the process should go faster I think.

In practice I suppose work staff would be larger to substitute folks on their hand molt days off.

 

Thoughts?

 

Not sure about dexterity, but per scifi desire, I want dexterity to be on par with normal humans.

They also have tiny hairs on the exoskeleton that allow a sense of touch.

Edited April 3 by Spacescifi

[Nuke]

human hands are actually quite devolved from our ape roots. though still enough to make us able toolsmiths.

for exoskeletons, take your typical crab claw, square it up a bit, elongate, and multiply by 5.

also a big fan of cephalopod aliens. tenticles are actually quite dexterous but aquadic environment might limit technological progress.

and bombardier beetles are a thing.

figure when designing a non-humanoid alien is to look at all the tricks life has managed here. imagine the evolutionary pressure that gets them there. then figure out what kind of evolutionary pressures are in the setting. once you throw genetic engineering into the mix all bets are off. but you are probibly going to start with an existing species as a substrate and then adapt changes to it, often from other species of compatible genetic makeup (pretty much from its own biosphere). cross sphere intermixing might be a hallmark of more advanced genetic engineering. being able to create a species from scratch would require god tier genetic engineering.

Edited April 3 by Nuke

[kerbiloid]

Spoiler

Spoiler

Spoiler

Only brain and family souvenirs in a protected shell, connected to the metabolic system of the robobody.

P.S.
Interesting fact.
When you are beating something with fist, you actually accelerate the pack of bones with power of muscles, and use your bones as a projectile.

 

[Shpaget]

How often do you find yourself in need of lighting a fire in everyday life, where such ability would be desirable?

[Terwin]

Anywhere you transition from flesh to bone/chitin is a possible vector of infection.  Much like our gums need regular maintenance to avoid infections that lead to tooth loss, even though they are in an environment that is hostile to most microbes.

Why make the hands out of chitin?

Also, a small tube on the back of the arm should be less prone to clogging/obstruction(sort of like a urethra and just as prone to infection if not kept clean). 70' seems unlikely, even 20' seemed pretty optimistic and you still need to hit the same spot with both squirts, so anything more than 5-10' is probably useless unless a majority of an individuals caloric intake is dedicated to producing the liquids along with a large internal reservoir to build up enough to have a decent chance to hit farther away. 

(How far away can you spit and hit a quarter laying on the ground, consistently enough to be useful when you only get 1 try per day?  Now try the same trick with your urethra, but you only get 0.5-1ml per day and you need to hit the same quarter-sized patch with both arms.  A palm-vent would be even worse as even finger-placenent would affect the stream direction.)

 

Also, humans are expert throwers, so don't pretend your theoretical species is just really better at rage, as humans are already fairly optimized at that.

 

Tldr; a bi-reactant biological ranged weapon, even if feasible to make, would be terrible to use and probably not have a greater useful range than an extendable club/baton or a baseball bat.

 

[kerbiloid]

2 hours ago, Shpaget said:

How often do you find yourself in need of lighting a fire in everyday life, where such ability would be desirable?

Smoking.

[Shpaget]

19 minutes ago, kerbiloid said:

Smoking.

Given the ability, you would opt to squirt high speed jets of hypergolics at your face rather than carry a lighter in your pocket?

[darthgently]

2 minutes ago, Shpaget said:

Given the ability, you would opt to squirt high speed jets of hypergolics at your face rather than carry a lighter in your pocket?

Ever try to flick a lighter with lobster claws?  

[kerbiloid]

6 minutes ago, Shpaget said:

Given the ability, you would opt to squirt high speed jets of hypergolics at your face rather than carry a lighter in your pocket?

He suggested. You asked. I explained.
I'm just a consultant.

Btw, hypergolics don't smoke, due to low carbon amount.
Sometimes they vent excessive oxidizer on launch.

[Nuke]

what is it exactly that bombardier beetles excrete? what would its isp be? beetle powered rockets anyone? makes more sense than fungus drive.

[kerbiloid]

Hydroquinone and hydrogen peroxide.

But the temperature is just about the boiling point of water, so it could work only in zero-g.

P.S.
Interesting fact: the hydroquinone process is used by humans to produce the hydrogen peroxide.

So, probably they could herd the bombardiers on Mars as a source of the latter.

[TheSaint]

I find a better point of divergence from human-centric thinking.

I am a alien arthopod intelligence. I am hetrosexual, but I may not conform to the norms of what humans define of heterosexuality.  My familial unit is not father-mother-siblings. When I emerge from my egg, my parents are nowhere to be seen. Instead, my familial unit is the other creatures who emerge from the same clutch of eggs at the same time that I do. The same eggs who were stuck to the same physical object as I was. My stick. (Not stick in the physical sense. Ten-thousand years ago it may have been a stick on a tree or a bush. Now it may be a cluster of birthing appliances in a laboratory. It doesn't matter. It's a "stick".) I can't breed with my siblings in my stick. That's wrong. But I can breed with creatures who are like me from other sticks. I can breed with creatures who are like me from other sticks. But I cannot breed with my siblings. However, I can trust my siblings. To death. When my siblings trust others, from other sticks, and breed with them, I trust them. Sort of. But not like I trust my siblings. They I trust. To death. And in this crazy matrix of trusting and not trusting we somehow create a civilization. That makes it to the stars. And contacts humanity. Who is completely different from us. What in the actual?

Biology leads to psychology. Learn it. Live it. Write it.

[kerbiloid]

We the cell. We are the pack of united organelles.
Hundreds megayears ago we were separated. We were different archaea. Then we had entered into the largest of us to parasite on it, to eat it from inside. But we got lazy, we got primitive, we got rudimentary. The host has co-opted us.
Now we are the one. Together with the host. We are not just a cell, we are the Eukaryote, which means "good-cored". We born together, live together, and split to reproduce like a family.
We form huge colonies together with others of our kind. The colonies got sapient. They have their own mind. We don't know, why. Their mind is far beyond ours. This is quantum physics at the low-level reality of the Universe.
Now our sapient colonies are procrastinating on the forums and writing various things. Like this one.

Edited April 4 by kerbiloid

[darthgently]

4 hours ago, kerbiloid said:

We the cell. We are the pack of united organelles.
Hundreds megayears ago we were separated. We were different archaea. Then we had entered into the largest of us to parasite on it, to eat it from inside. But we got lazy, we got primitive, we got rudimentary. The host has co-opted us.
Now we are the one. Together with the host. We are not just a cell, we are the Eukaryote, which means "good-cored". We born together, live together, and split to repdroduce like a family.
We form huge colonies together with others of our kind. The colonies got sapient. They have their out mind. We don't know, why. Their mind is far beyond ours. This is quantum physics at the low-level reality of the Universe.
Now our colonies are procrastinating on the forums and writing various things. Like this one.

On a related note, iirc, the number of coevolved bacteria and viruses in the human body outnumber the official human cells (which themselves house mitochondria that are somewhat independent entities in themselves).  Amazing stuff