Native vision type under extreme conditions?

[Hide]

I have been wondering, what kind of vision should a creature have under extreme conditions such as: Dark-cold places like Jupiter and very-illuminated-hot places like Venus.

I was thinking infra-vision could work in cold-dark places, but then I realized that (for example) polar bears are insulated and hence you might fail to stop them.

So, maybe creatures native to very cold places are going to be as prepared (insulated) for that matter as well (rendering infra-vision useless).

When it comes to hot places, normal vision might have issues too. How could you see without getting dazzled?

Thanks!

[AlexanderHowl]

Jupiter gets pretty hot real quickly. Paradoxically, the upper atmosphere can reach 1000K, and the coldest is at a 'height' of 100 km. At around -60 km, you get Earthlike temperatures and things get progressively warmer the further you get down. For example, the liquid metallic hydrogen oceans are thought to be around 10,000 K, which is probably too high for anything we could recognize as life.

Electromagnetic vision is unlikely in either Jupiter or Venus, though it is marginally more useful on Venus. Jupiter life would likely depend on magnetic and electrical senses and, in the depths of the atmosphere, sonar would be likely. If there is life near the liquid metallic hydrogen oceans (which would be radically different than anything we know), they would likely also use sonar for navigation.

[Anthony]

It is worth remembering that creatures from extreme environments are unlikely to interact with creatures from 'normal' environments without at least one of them being in an environment suit that will probably be providing sensors, so classifying their senses in human-relative terms isn't too important. That said:

Anywhere in the solar system that sunlight reaches is viable for normal vision, full sunlight at the orbit of Neptune is still adequate for human performance. For areas under the cloud tops, it will rapidly turn dark anywhere that has clouds, and you wind up with similar options to deep sea fish on Earth: mostly light emission or non-visual senses. Infravision is unlikely to be common because it's hard to make infrared work well without refrigerated sensors, and refrigeration is generally hard to evolve and not going to be healthy for biological sensors. Sonar is easy enough everywhere, electromagnetic field senses or even active radar are possible though not common on Earth.

[whswhs]

Originally Posted by Anthony

Infravision is unlikely to be common because it's hard to make infrared work well without refrigerated sensors, and refrigeration is generally hard to evolve and not going to be healthy for biological sensors. Sonar is easy enough everywhere, electromagnetic field senses or even active radar are possible though not common on Earth.

Is there an Earth lifeform that uses radar? I haven't heard of one.

[Anthony]

Originally Posted by whswhs

Is there an Earth lifeform that uses radar? I haven't heard of one.

Not that I can think of, electric eels do have an active electromagnetic sense but it seems to work differently. Passive field sensors are present on a number of fish, though.

[khorboth]

It's worth noting that on Earth, we see in a really very narrow band of the EM spectrum. Even crazy critters like mantis shrimp don't see a wide band. The best idea is that as we started seeing, things evolved to be seen in particular ways in that range so as to breed, intermingle, cooperate, camouflage etc. So, our eyes, pigments, and strategies all co-evolved in one tiny bit of the spectrum. One which works great for the bands which get in through our atmosphere and are reflected by stuff down here. And humans in particular can discern variations in that spectrum quite well.

So... on another planet, what distance sense came along first and/or became dominant? Probably another band of the EM spectrum. Probably not much wider or more narrow than our own, but some. Probably pretty close to the same because longer wavelengths require bigger eyes to gather and smaller ones tend to go through solid objects. But... near UV and IR are not unreasonable. or something that encompasses our range and both ends.

Sonar is not an unreasonable choice for dense atmospheres either. It's popular in our oceans and has a few takers in the skies. If EM interference is common, maybe that's a good idea.

Electroreception is a possibility. Sharks and a few others sense the current generated by living nerves. It's not a good stand-alone sense as you don't notice rocks, but it's nice for hunting.

In a dense atmosphere, some kind of air-current-based tremmorsense seems far-fetched but like a fun thing to play with.

[whswhs]

Originally Posted by Anthony

Not that I can think of, electric eels do have an active electromagnetic sense but it seems to work differently. Passive field sensors are present on a number of fish, though.

It's at best a near-field effect, not a far-field one like actual radar. I wrote both types of sense up for Enhanced Senses after reading a couple of books about electric fish. I think I did the passive one as Detect and the active one as a variant on Vibration Sense.

[whswhs]

Originally Posted by khorboth

It's worth noting that on Earth, we see in a really very narrow band of the EM spectrum. Even crazy critters like mantis shrimp don't see a wide band. The best idea is that as we started seeing, things evolved to be seen in particular ways in that range so as to breed, intermingle, cooperate, camouflage etc. So, our eyes, pigments, and strategies all co-evolved in one tiny bit of the spectrum. One which works great for the bands which get in through our atmosphere and are reflected by stuff down here. And humans in particular can discern variations in that spectrum quite well.

Part of the problem with using other spectral ranges is that only a narrow band of frequencies are energetic enough to cause changes in the internal chemical state of receptor molecules without disrupting them. Thermal infrared causes vibrational motion but doesn't promote electrons to higher orbitals. You can go down into NIR or up into UV, but not much beyond that. There's also the issue that visual resolution depends on wavelength; if your retinal cells are closer together than half a wavelength you won't gain any actual acuity. So the similar triangles of height/width of target object:distance to target object::retinal cell separation: eyeball diameter constrain your visual precision. If you use thermal IR, you're going to have really poor resolution.

[Anthony]

Originally Posted by whswhs

Part of the problem with using other spectral ranges is that only a narrow band of frequencies are energetic enough to cause changes in the internal chemical state of receptor molecules without disrupting them.

It's not that narrow, and you don't necessarily need single-photon detection anyway. The biggest determiner of the wavelength of terrestrial vision is probably the absorption spectrum of water (liquid is very bad outside of the visual range, gas is better but still not good).

[whswhs]

Originally Posted by Anthony

It's not that narrow, and you don't necessarily need single-photon detection anyway. The biggest determiner of the wavelength of terrestrial vision is probably the absorption spectrum of water (liquid is very bad outside of the visual range, gas is better but still not good).

It's not so much a question of single-photon detection; as I understand it, the human eye shows a neural response to single photons, but it takes several photons hitting the same neuron close together to initiate a neural impulse, possibly as a way of limiting the effect of visual noise. But if you have wavelengths that can't produce a significant chemical potential, your detector isn't going to look like an eye; it's going to look, for one example, like a rattlesnake's pits.

But absorption spectrum certainly is a further concern; for example, it's why some animals (bees and some birds, I believe) can see near UV, but no animals have receptors for vacuum UV.