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Ash Small

Sun Mar 25 2012, 11:20PM

Registered Member #3414 Joined: Sun Nov 14 2010, 05:05PM
Location: UK
Posts: 4245

Proud Mary wrote ...

Do bats process their return echoes into something we could understand as a 3-D picture? Are the bats 'seeing' with sound?

The simple answer is 'yes'.

Conundrum

Fri Mar 30 2012, 06:44AM

Registered Member #96 Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4061

Bats are older than humans evolutionally speaking, by several tens of MY IIRC.

Its possible that somewhere in nature there exist lifeforms capable of generating and using RF and THz radiation, just as there are luminescent bacteria.

-A

Forty

Fri Mar 30 2012, 04:21PM

Registered Member #3888 Joined: Sun May 15 2011, 09:50PM
Location: Erie, PA
Posts: 649

Mantis Shrimp have some pretty crazy eyes. Trinocular vision in each eye and can perceive polarized light, including UV. One species can even detect 6 different kinds of polarized light.

I'm pretty sure not all bats are completely blind, so they probably convert some of the sound information into visual. I'd like to see more UAVs using bat "vision"

Heavy metal DNA sounds pretty hardcore. I imagine there'd be problems with the heavy DNA molecules separating out unless the rest of the cell was dense (I'm picturing all the DNA pooling at the bottom of the cells due to gravity)

I haven't tried observing IR light in total darkness, but I can usually sense it a bit in the form of eye strain.

The ordering of this post is completely backwards isn't it.

Bored Chemist

Tue Apr 03 2012, 01:17PM

Registered Member #193 Joined: Fri Feb 17 2006, 07:04AM
Location: sheffield
Posts: 1022

Proud Mary wrote ...

Veterans of the British Atomic Tests of the 1950s reported that they could see the image of the bones in their hands when pressing their clenched fists to their eyes miles from the site of thermonuclear explosions - presumably due to gamma rays.

X-rays too can be perceived by the human eye under certain conditions. See:

Lipetz LE The X-Ray and Radium Phosphenes Brit. J. Opthalm. (1955) 39, 557

Which you can download free here:

I wouldn't presume it's down to gamma rays.
At best they might give a shadow-picture but the bones of the hand are bigger than the retina.
without a lens they simply couldn't form an image and the eye's lens doesn't focus gamma rays.

Proud Mary

Tue Apr 03 2012, 01:31PM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

Bored Chemist wrote ...

Perhaps you are right. The rerence to 'pink x-rays' in this account suggests that the effect could be due to light intensity - or some other effect - alone:

"We saw a bright, brilliant light," he recalled. "It was as if someone had switched a firebar on in your head. It grew brighter and you could see the bones in your hands, like pink X-rays, in front of your closed eyes." ' Source:

I wouldn't expect pink to be perceived in the perception of x-ray and beta-particle phosphenes.

Vision Res. 1990;30(8):1139-43.
The radiation phosphene.
Steidley KD.

Abstract

A low flux of X-rays below the Cerenkov energy threshold generates a phosphene by direct action on the retina without a fluorescence in the ocular media. X-rays above the Cerenkov threshold can generate only a faint luminescence in the lens and cornea. From experimental work on humans in 1905 with unencapsulated radium, it is known that approximately 80% of the intensity of the radium phosphene is from the beta-ray component and approximately 20% from the gamma-ray. From calculations of the photon yield due to Cerenkov radiation in the eye from radium, one finds intensities of approximately 90% and approximately 10% for beta and gamma-rays, respectively, if only Cerenkov radiation is considered. Thus, one may conclude that the dominant mechanism of the radium phosphene is Cerenkov radiation, primarily from electrons and not fluorescence as previously speculated. The term "radium phosphene" is a misnomer and should be subsumed along with the X-ray phosphene and particle induced visual sensations under the name "radiation phosphene".

Conundrum

Tue Apr 03 2012, 06:26PM

Registered Member #96 Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4061

Wonder if lifeforms with electrochemical storage (ie using copper salts) exist, charging up their internal "batteries" using sunlight?

-A

Steve Conner

Tue Apr 03 2012, 06:45PM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

The pink x-ray effect could well have been caused by the sheer intensity of visible light from the bomb blast.

All life forms run off electrochemical energy. The chemistry is just a little different to man-made batteries, it works by adding and removing protons from a chemical called ATP. But the difference isn't really that major, protons are protons. So, plants already do what Conundrum said.

Electric fish use specially adapted muscle cells to generate hundreds of volts from this reaction, stunning their prey. Maybe one day biotech will give us solar panels that you can grow at home, from electric plants or algae.

Proud Mary

Tue Apr 03 2012, 07:49PM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

Aside from extra-rational religious belief, is there any good reason why the bio-diversity we find here on Earth will not also be found on the planets of other stars?

Perhaps any self-regenerating autonomous system that can be assembled from the materials of the universe will come into existence somewhere in space-time, so Andre's idea of variant modes of photosynthesis occuring in animals - rather than only in plants - doesn't seem far fetched to me.

Steve Conner

Tue Apr 03 2012, 08:30PM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

He said lifeforms, surely that includes plants anyway?

We all live off photosynthesis. The way evolution worked out, it made more sense for animals to delegate it to plants by eating them. I wonder how much greenery an elephant munches its way through, and if it could grow the equivalent amount on its own body surface. Probably not, at least on Earth. It might work out more favourably on a planet with lower gravity or a brighter sun.

Nicko

Sun Apr 08 2012, 05:36AM

Registered Member #1334 Joined: Tue Feb 19 2008, 04:37PM
Location: Nr. London, UK
Posts: 615

Proud Mary wrote ...

Do bats process their return echoes into something we could understand as a 3-D picture? Are the bats 'seeing' with sound?

Bats' echolocation (for those that use echolocation) is very subtle - the pulses of acoustic energy they emit are typically not a single frequency or constant power & repetition - the pattern varies by species and indeed, subspecies and further, what the bat is up to - e.g. I have two species of Pipistrelles living around my house - the "common", whose calls centre around 45kHz and the quaintly named "soprano" at 55kHz.

The calls are typically frequency sweeps of varying energy & range and change as the bat homes in on its target. A few years ago I built a real-time dsp-based bioacoustic spectrum analyser to study our local bats -

- the end game was to be able to automatically identify the species and subspecies by acoustic analysis only - this is of particular use in the field, e.g. in caves or deep jungle, where the normal method of identifying species is invasive, vis. using mist netting to capture specimens - difficult if the sample is above the tree crown.

Note that as their targets are fairly static, fruit bats don't use echolocation to find fruit (!!) - they tend to have a good sense of smell and good eyesight.

Back to your question - no-one knows how bats use the data they gather. There is intense speculation regarding how the returned information is processed, but no definitive answer.

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