When soldiers go on operations at night, they use night vision devices, which allow them to see even when the environment is very dark. There are several techniques for night vision, one of them is called "starlight amplification" and it allows you to see even when the light is extremely weak. In this technology, the image appears in green color.
By: Dr. Netzah Parbiash, a young Galileo
When soldiers go on operations at night, they use night vision devices, which allow them to see even when the environment is very dark. There are several techniques for night vision, one of them is called "starlight amplification" and it allows you to see even when the light is extremely weak. In this technology, the image appears in green color.
Why is the night dark?
First of all, it is important that we understand why the night is dark. This may sound like a simple question, but it is not obvious. In fact, if you think about it, considering all the billions of stars in the universe that spread light in a fixed way - it is likely that the night will also be fully illuminated. The difference between the expectation that the stars will light up the sky and the darkness we know from the night sky is known as "Olver's paradox". The accepted explanation for the paradox is based on the fact that the universe has been expanding ever since the big bang, and that the age of the universe is finite (that is, it has existed for a long time, but not an infinite time). Does this mean that the night is completely dark?
During the day we mainly see the light from the sun, which is the closest star to us, but not only from it. Some of the light also comes from distant stars (yes, even during the day! Stars shine not only at night) and sometimes also from the moon, which returns to us a small part of the sun's light that hits it. When the sun sets, it illuminates the other side of the Earth, and then we begin to notice the stars, which are distant moons that produce their own light (as opposed to the planets and moons that reflect the sunlight hitting them). When the moon is full the night sky is relatively bright, and then it is also harder to see the stars.
Thanks to Einstein
Our eye is sensitive to visible light, which is the range of wavelengths between 400 and 700 nanometers in the spectrum of electromagnetic radiation. During the day, or through artificial lighting, it is possible to see different objects because the light hitting them is reflected with a high enough intensity. At night, when the amount of light is very low, the light reflected from the objects is often not enough to enable vision without an aid.
A night vision device based on starlight amplification technology, built from an optical system reminiscent of binoculars. An electronic amplification tube system that translates weak light on one side of the device into an electric current that is amplified in the tube and converted back to light on the other side. To understand the physical process on which it is based, let's go back to 1905, when Albert Einstein published the explanation for the photoelectric effect. Understanding the photoelectric effect was of immense importance in the development of modern physics, and especially the term "photon" which helps in understanding the essence of light particles. Einstein received the Nobel Prize in Physics in 1921 for explaining the phenomenon.
The photoelectric effect is a physical phenomenon in which electrons are ejected from the surface of a metal, when it is struck by suitable electromagnetic radiation and absorbed by it. In other words, a particle of light (photon) hits the metal, and if the appropriate conditions are met, the photon will be absorbed by one of the atoms of the metal and an electron will be ejected from it. When the phenomenon occurs inside a tube with an anode (negative electrode) and a cathode (positive electrode) - the emitted electrons create an electric current. By supplying an external electrical voltage, the electrons can be accelerated, thereby adding energy to them and increasing the current.
- The writer is a scientific vice president at Caruso Science Park
The article was published in the September 2014 issue of Young Galileo
Want to read more? To receive a young Galileo magazine as a gift
29 תגובות
God
just a question. Do you know what Pinoza thinks about you? Read!: Maybe you'll get a little smarter.
God
There is no point in continuing the conversation between us.
My thesis is on evolution. I don't think I'm smart either, but at least I'm not rude who doesn't understand what I'm talking about.
Nissim, you are a stubborn person and probably not that smart!
If you don't understand the basis of genetic inheritance, really what's the point?
I still can't believe that you couldn't understand the connection between the inheritance of color vision and the inheritance of the ginger gene?!
And if a theory presented in Wikipedia does not convince you, how can I convince you?!
God
The redheads are indeed "extinct". But that has nothing to do with what I said. I was talking about seeing shades.
In any case, you do not rule out the other explanations, and without that there is no point in this conversation. You have a possible explanation (in your opinion) - but that's all.
the snake
God
Why do not you answer me? In addition to what Job did that you harassed him, didn't you resist the temptation? On your forehead will be engraved the letter of Cain. As inclusive as you are.
I have no idea what you are talking about, does it have to do with your folktales and all your strange customs?!
Because if so, I'm still thinking and trying to understand what the hell you're doing!
1) Again, there are animals that have evolved under conditions similar to humans that even see black and white. The fact that there are examples that strengthen your claim does not prevent one counter example from invalidating...
2) There are green mambos and there are black mambos. In general - the chimpanzees are black... Why didn't they develop a simple defense mechanism like the color green?
Maybe there were some and they weren't and at some point the species with the ability to see shades survived because this ability gave a greater advantage (like identifying cows worthy of food) and not just to camouflage itself!
3) You wrote "You asked me why the snake did not develop vision like ours and the answer was that it developed the ability to camouflage and that was probably enough for it". According to what you say - guessing that he will diagnose more shades will not be an advantage. This is simply not true.
(According to what you say - guessing that he will diagnose more shades would not be an advantage)
You are just putting things on my keyboard by personal conclusions!
Because I wrote in the passage:
Now imagine that a mutation is created (the ability to see shades of green if it's not clear to you or any other ability) that gives the green snake a survival advantage in addition to its ability to assimilate among green shades, the same mutation is passed on to the offspring and thus a new ability is created in addition to its green shade (evolution)
4) You assume that the offspring of a couple, one of whom sees colors well and the other less well - then their color vision will be "average". I don't know of any way that could be true.
(You'll be surprised the redheads are extinct)
God
Why do not you answer me? In addition to what Job did that you harassed him, didn't you resist the temptation? On your forehead will be engraved the letter of Cain. As inclusive as you are.
God
1) Again, there are animals that have evolved under conditions similar to humans that even see black and white. The fact that there are examples that strengthen your claim does not prevent one counter example from invalidating...
2) There are green mambos and there are black mambos. In general - the chimpanzees are black... Why didn't they develop a simple defense mechanism like the color green?
3) You wrote "You asked me why the snake did not develop vision like ours and the answer was that it developed the ability to camouflage and that was probably enough for it". According to what you say - guessing that he will diagnose more shades will not be an advantage. This is simply not true.
4) You wrote, "This ability gave a survival advantage, something that is not expressed these days, and therefore this ability will disappear when humans assimilate with humans who have a limited ability to absorb green shades, and there are some."
You assume that the offspring of a couple, one of whom sees colors well and the other less well - then their color vision will be "average". I don't know of any way that could be true.
But listen - as long as you haven't ruled out the other possible explanations, what you say has no meaning.
http://en.wikipedia.org/wiki/Evolution_of_color_vision#Primates
We would expect creatures in a similar situation to develop the same feature - this is not the case
1) The claim is incorrect, there are animals that have much better vision than humans and the shades of color they can perceive
Exceeds ours
2) Evolution is a complex subject and sometimes chooses to develop different abilities between species of animals that live in the same area
You asked me why the snake didn't develop vision like ours and the answer was because it developed the ability to camouflage and that was probably enough for it
Now imagine that a mutation is created that gives the green snake a survival advantage in addition to its ability to assimilate between shades of green.
3) Regarding why the person still sees the color green:
This ability gave a survival advantage, something that is not expressed these days, and therefore this ability will disappear when humans assimilate with humans who have a limited ability to absorb green shades, and there are some.
God
You have a possible explanation (let's say) for a certain feature. To test the explanation, you must first rule out any other possible explanation. You haven't done it yet. It is also necessary to examine what the explanation predicts. For example, we would expect creatures in a similar situation to develop the same feature - this is not the case.
You wrote that one should ask why we still see many shades of green. There are 2 possible answers to this. The first is that there is no survival advantage in reducing the number of shades we recognize. The second is that the mechanism is built in such a way that it cannot change - there may not be a genetic possibility to reduce the number of shades, without doing serious damage.
But - start by rejecting the explanations I gave and Shmulik's explanation.
Nissim, by the way, you mentioned it (perhaps to distinguish between poisonous and edible plants) and it is true to the same extent of diagnosing predators!
And the full answer in my opinion is:
1) Diagnosis of predators
2) Diagnosis of poisonous plants
Miracles
God
True, there is a mamba, a green snake that lives in Africa. But... the mamba doesn't see colors. If your explanation was correct, it would also apply to Mamba.
Ask yourself why man still sees the colors of green even though he does not live among trees today.
Each animal developed its abilities/senses according to its origins, there are "tools" that a living creature can develop according to its living area, but to change their basis requires a longer evolutionary time, it is possible that this species of snake developed its abilities in a period not far from our time today in a completely different area and to change The base of his abilities needs a longer evolutionary time! I also believe that man's ability to see shades of green will change over time because man no longer needs this feature.
God
True, there is a mamba, a green snake that lives in Africa. But... the mamba doesn't see colors. If your explanation was correct, it would also apply to Mamba.
I think you have to take into account that these are peri-historical periods and the type of species that lived during this period are completely different from what exists today!
And regarding green carnivorous species, there are several types of highly venomous snakes that live on trees and are green in color.
Undoubtedly death to the monkey when struck!
God
Why did you expel Adam from Eden and why did you bring the flood? The mark of Cain will be engraved on your forehead!!!
Miracles
God
You meant to add "I think that" before your comment right? The fact that something is logical and can be an explanation for a phenomenon does not prove that the explanation is correct.
Miracles, I mean when God says God knows! 🙂
Now on a serious note, you are right I took note.
God
How many green carnivores do you know?
Ask more and more questions. Here comes what "God" wrote. His explanation is wrong of course, because in order to identify a predator among green trees, it would be better if there was no discrimination in the shades of green!! Think - back then, anything not green was much more noticeable.
Everyone knows that predators have developed camouflage mechanisms to avoid standing out, now let's guess what shade a predator should develop on its skin/fur to be less noticeable among green trees?! You have to take into account that these are peri-historical periods and the type of species that lived in this period are completely different from what exists today!
Shmulik / God
The graph in your second link (Shmulik) also shows a peak in blue, even though it says green. But, let's assume the peak is green:
1) Is this the peak at ground level?
2) What was the effect of the atmosphere while our vision was developing?
3) Who cares about the color of sunlight anyway? Isn't the color of the objects in the landscape more interesting?
4) Is there necessarily a connection between the amount of energy and the ability to distinguish shades?
5) Again, do other animals also distinguish between more shades of green?
There are more and more questions. Here comes what "God" wrote. His explanation is wrong of course, because in order to identify a predator among green trees, it would be better if there was no discrimination in the shades of green!! Think - back then, anything not green was much more noticeable.
By chance - it turns out that colorblind people see camouflaged objects better than others 🙂 Read here - http://rspb.royalsocietypublishing.org/content/248/1323/291
There are many things that are "just like that" and do not give an advantage to the organism. Most people have 3 types of color receptors (some have 2, some have 4). Presumably, one of them will have a wider field, right?
God
You meant to add "I think that" before your comment right? The fact that something is logical and can be an explanation for a phenomenon does not prove that the explanation is correct.
The reason why the human eye sees the shades of green color better is because man as we know
Evolved from the monkey, in ancient times the area of the jungles was huge compared to today and we all know what the common color is
In the jungles, in order for the monkey to be able to identify predators among the many shades of green in the jungles, the monkey's eye developed
To absorb green shades in a better way compared to the other shades. And that is why man sees shades of green better!
Miracles,
From several links I checked recently (except for the wiki) the claim is that the Peak emission is green or green-yellow
http://solar-center.stanford.edu/FAQ/Qsuncolor.html
http://solar-center.stanford.edu/SID/activities/GreenSun.html
Regarding the article, here is a nice clip from YouTube: Why is it dark at night?
https://www.youtube.com/watch?v=gxJ4M7tyLRE
Shmulik
I know that we see more varied shades of green of another color, and that is indeed why NVGs are presented in green. But - the peak of the sun's emission is precisely in blue - (the peak at 456 nm, when green is around 555 nm).
Therefore, I think the reason for our diagnosis is different. One possible reason is the need to distinguish between different foliage, perhaps to distinguish between poisonous and edible plants.
Another possible reason is that it is an artifact of the canon of evidence, that is, a chemical reason in general.
A third option is philosophical in general - we have 3 color receptors so it makes sense that one of them would be the most sensitive...
Miracles, I have no idea, but the claim is that you can invest less energy in the green color than in the red color and the eye will absorb the green better, up to a certain threshold (I don't remember what the threshold is). Such experiments were conducted
Shmulik
If this explanation is correct, we would expect all diurnal animals to distinguish between more shades of green. is it true?
The eye perceives green better than other colors because this is the frequency at which the sun emits the most radiation
http://he.wikipedia.org/wiki/%D7%A7%D7%A8%D7%99%D7%A0%D7%AA_%D7%94%D7%A9%D7%9E%D7%A9
Hanan
But why green?
Because the human eye perceives the shades of green color better compared to the other shades!
But why green?