h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Entry: To See - A16670685
Author: burnkrn - U2546897

i wrote this entry because i felt it was something that didn't really have much of a forum on the h2g2. and i feel very enthusiastic about it as a subject. please, if anyone has anything to add or correct, let me know, I'd love to get your feedback! UC?

What does UC mean?
It's quite interesting although it will need quite some work before it is ready for the guide. Your attempts at being funny failed, in my opinion, take this for example:

>> or for that matter that they are still there.
<< How often do you think it happens that you've lost your eyes and don't know? Or that you've lost them in the first place?

Hi burnkm,

I feel that this is going to be a useful and interesting addition to the Guide - but there's a bit to do yet.

I noticed a couple of typos/spelling errors, at least e.g. phisical > physical
mvement > movement

So run it through a spell checker.


'Sight is our main access to the world as we know it. A quarter of our entire brain is devoted to the function of vision'.

> Worth pointing out that more info enters human brain through the eye than through any other sense organ (Encyclopaedia Britannica). Containing some 170 million rods and cones, 70% of the human body's sensors are found in the eyes.

'Without this [ability to focus] we would merely see a vast mishmash of colours...

> Worth pointing out that humans can distinguish over 10,000 different colours.


'...from Macular Degeneration, the most common form of blindness in the western world. -see here for more information.

> macular degeneration (i.e. lower case initial letters - there are a couple of e.g.'s of this).

> Other common forms of blindness include glaucoma (inhcrease in eyeball pressure); cataract (lens becomes opaque) - common in diabetics; infectious diseases (100,000 children per annum go blind as a result of measles. PS Are parents who refuse the measles jab for their children aware of this? For an African or Asian child who has not been immunised, measles can be deadly. The child can go incurably blind in just a few days. There are also infections due to inadequate cleaning of contact lenses, due to Acanthamoeba keratitis).


'This is both neccesary and vital for clear sight to work in three dimensions and for the brain to recognise and process information'.

> You could use the phrase 'stereoscopic vision' here. Vital for judging distance e.g. for our ape fore bears when swinging in the branches of trees, and for hunting, and so occurs chiefly in predators.

'Bees and many other insects can detect ultraviolet light which is useful to hone in on flowers'.

> home in...

Cats' eyes catch 50% more light than ours and are eight times more sensitive than ours at night.

and 'Owls use the reflective 'shininess' in their eyes to optimise on capture of what little light remains during darkness. Owls have a sensitivity to low light intensities 50 to 100 times greater than that of unaided human night vision'.

> Worth pointing out that, of the estimated 900,000 0r so animal species on the planet (i.e. nearly 1M), half of these are nocturnal, and have extremely sensitive eyes. Many use infra-red surveillance.

(n.b. The bat is PERFECTLY adapted to life after dark, using ultrasound!

The human eye is so sensitive that it can detect a lighted candle at a distance of 1 mile (1.6 km)

Thank you for taking the time to read through my article.

>>or for that matter that they are still there.
I feel this statement is still a legitimate possibility, because people do regularly lose their eyes in places in the world that we are lucky not to live in. eg. when waking up from an unconcious state.

I was going for accuracy, not humour. trust me, If I was trying to be funny, I think you would have probably split your sides. but for the sake of accuracy, I included this in order to state the obvious.

Thank you for taking the time to read through my article.

>>or for that matter that they are still there.
I feel this statement is still a legitimate possibility, because people do regularly lose their eyes in places in the world that we are lucky not to live in. eg. when waking up from an unconcious state.

I was going for accuracy, not humour. trust me, If I was trying to be funny, I think you would have probably split your sides. but for the sake of accuracy, I included this in order to state the obvious. UC?

thanks for the suggestions. i think you will be pleased by my new and improved updated version. By all means though, I welcome anyone who has some positive criticism not to hold back, but to let me know of any possible ideas to add to it, or suggestions to improve the content in any way... because i know you can see better than i can, as i am blinded to my own flaws....

I'll go through the amended version as soon as I find the time.
>>I feel this statement is still a legitimate possibility, because people do regularly lose their eyes in places in the world that we are lucky not to live in. eg. when waking up from an unconcious state<<

Well, I had no idea, maybe you could add a footnote o explain this?

I've no idea whatever what the following statement means. Please could you explain:

'The maximum sensitivity of a typical light-adapted eye is at around 555nm which is in the green region. If in doubt, look for the light switch'.




'The cells receive and retransmit the information just like passing on a bucket, until it gets to the brain via the optic nerve'.

May be helpful to use the phrase 'chain gang' here. (I initially mis-read it as 'pissing on a bucket'!)

'The most massive system in the human brain, the visual cortex, will then process the visual image at higher-levels'.

> This is another piece of information which reinforces that 'sight' is our (human's) most important sense. Maybe it could be incoroprated where the rest of that info is?



As humans we have what we call stereoscopic vision.
> Humans, in common with many other animals, particularly mammals... (Would this be true do you think? Are there any non-mammals that have steroscopic vision? Do any mammals not have stereo-vision, for e.g. whales? I'm not sure on these points at the time of writing).


Other Forms Of Sight

I think it might be useful/informative to use the phrase 'electromagnetic spectrum' here. e.g. Humans perceive wavelengths in a very narrow part of the electromagnetic spectrum, known as the visible region. Many species can perceive wavelengths well outside this range, for example:

Bees and many other insects can detect ultraviolet light which is useful to home in on flowers.

At the other end of the spectrum, some snakes are sensitive to infra-red which they use to detect the presence of warm-blooded animals.
The eyes of a goldfish are so sensitive, they can see the infra-red beams that control our TVs and videos.

ALTHOUGH cats appear to see in colour, they only between at the SHORT to MEDIUM WAVELENGTH region of the spectrum (medium to high frequency). Thus they see blues and greens, but no reds, oranges or browns. These colours would appear to them as shades of grey or purple. Cats' eyes catch 50% more light than ours and are eight times more sensitive than ours at night. N.B. The human eye is so sensitive that it can detect a lighted candle at a distance of 1 mile (1.6 km).

Owls use the reflective 'shininess' in their eyes to optimize on capture of what little light remains during darkness.

> Wonder if you should mention 'light amplification' here, which humans have emulated ion night vision equipment such as binoculars?

'Of the estimated 900,000 0r so animal species on the planet, half of these are nocturnal, and have extremely sensitive eyes. Many use infra-red surveillance'.

> Move this para higher up, e.g. immediately before the info on cats?

'[Birds have the greatest range of Dioptres of all animals. A Dioptre is a measurement of focal range, or distance that an animal can focus on. A human has around 14 Dioptres, while a diving bird has 50. That is why a hawk can spot a mouse from 1.5km high.'

> This doesn't really fit into the section on 'Othewr Forms of Sight'. It really belongs where you are talking about 'Stereoscopic Vision'


'Bats are not blind as the myth suggests. Many species in fact see very Much in a similar way that bats use echoes, dolphins also use sonar'.

In fact, bats and dolphins' 'see' in exactly the same way - by sonar/echolocation. (bn.b. put 'see' into inverted commas as I have done )


Hope this is helpful.

A

i thank you mr. la gib for your series of suggestions. i will not be able to work with all of them, but some of them are quite legitimate and i will fix them as soon as i get the chance. but not right now. please come back after the weekend and maybe i'll get some time to answer your questions, etc.
....Pissing on a bucket..... LOL........

well... I have done all the updates to the entry that i could think to do.
could anyone please tell me what they think?
I hope it is what you might call finished. i really do welcome any sort of comments or suggestions. hell, even downright critisism wouldn't hurt. Ok, well it would hurt, but if it makes the article stronger then by all means...

If you can also tell me, what do you think? Is anything stopping this article from getting edited? and if so, what could be done to fix it?

I think the first Header needs not to be used. You can still use the information and a definition but a header isn't needed right at the beginning. Also there may be quotes that you come across on the web that could be used as long as they are referenced properly etc.

Any more thoughts anyone?

Just that I read recently that birds can see into the ultraviolet.
http://www.bio.bris.ac.uk/research/vision/4d.htm

Interesting.

Your Guide Entry has just been picked from Peer Review by one of our Scouts, and is now heading off into the Editorial Process, which ends with publication in the Edited Guide. We've therefore moved this Review Conversation out of Peer Review and to the entry itself.

If you'd like to know what happens now, check out the page on 'What Happens after your Entry has been Recommended?' at EditedGuide-Process. We hope this explains everything.

Thanks for contributing to the Edited Guide!

Nice first entry! Congratulations.

thank you. I'm glad it is liked or appreciated in some way. this is an acheivement for me, and i know it certainly encourages me to continue to contribute to the site and to keep thinking of many more innovative ideas.

Congratulations, burnkrn
I really enjoyed your entry! I look forward to seeng more of your stuff