2023-05-17 10:07:41
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Wednesday May 17, 2023 and today I bring you one of science,
an example of the many that we can give from when science
is impregnated within culture, art and over time
We don’t even know why it happens.
But before that I want to make a claim.
A claim that would normally make…
Well normally.
What should I do in padrazos, but since we record every month and something like that,
great fathers because so many things come together that this is not going to fit.
So my demand from here is to stop teaching the little ones
and to the small songs that have things wrong scientifically.
It is something as simple as a song that says that when the sun goes down the moon rises,
Well, it’s a lie.
That’s not true, that happens once out of 28. Every 28 days it happens once, which is when the moon is full.
If not full moon, that does not happen. So, from here my claim to confuse the little ones about things
to astronomy and science. No, the sun also does not rise in the east and set in the west. But hey, we leave that for another day.
And well, what I was saying that reaches the general culture is also something like that, and it is that the…
Why are stars drawn with five points or six points? Why are the stars drawn like this?
The sun is a star and the sun has no point, the sun is a ball of fire and to draw you would have to draw a circle.
So what about the stars? Why are they drawn like this?
The reason is simple, but the explanation is not so simple.
The reason is simple because when we look at the sky at night and see a star, not the sun,
when we see a star, that star seems to be seen with little dots, with those points to the sides, and the simple explanation ends there.
The less simple and physical explanation also has nothing to do with the atmosphere or anything, it’s just
because when we see the image, when it prevails, a better said, the retina,
the image has gone through an optical system such as the eye.
And when going through an optical system, it goes through an opening.
Any optical system has an aperture, it cannot have an infinite aperture and this problem would be solved.
And at the moment in which one of light or a group of light aces, an image,
passes through an opening, such as the iris or the mouth of a telescope,
a phenomenon called diffraction occurs.
And it is the diffraction that produces those beams that have caused the stars to be seen over time,
in a childish way, they are drawn with points.
The most photographers in the place, if you are one of them, you will know that when you take a photo
and you close the diaphragm a lot, the aperture of your camera,
if you take a photo to a light, that light comes out with those spikes.
That is to depend on the shape of the iris, on the shape of the opening.
The more leaves that iris has, when it closes, the more circular it appears and the more it will
look like how the eye sees a star, which is still something quite circular,
although in the end it is a muscle that is achieving it.
Perhaps the easiest and most visual way to express it is with what is called the Huygens principle,
and it is that when you have a wave, when that wave advances in space, we are going to suppose
that in this case that the wave is light, this light is acting like a wave in this case,
when the opening of the optical instrument arrives, in this case of the eye, each point of the wave says
that principle generates new waves. At the moment when the light reaches our pupil, when it arrives
to the iris, imagine what happens at the edge. What happens at the edge is that the light at that point
generate another wave and there will be light beams that go out of that opening. Let’s say I eat, well,
is that in my head it is very easy, it diffracts and that’s it, but instead of the light going straight,
at those edges it will open up. How could I spend these three hours explaining the same thing in different ways?
ways and without a drawing it is very difficult to understand? If you look at your phone now you will be
seeing an image in which more or less I think it will be quite clear to you. This is what
in optics it is called the PSF. If you have the image of a point, well, if you have a point, like
It can be a star that is very far in infinity, it is a point. Mantenbalmente is punctual.
If we pass that object through an optical system, the image that the dot gives us
is the PSF. The closer a point is, the better the optical system, the further away it is
from that point, which is the original image, well, that system is worse. Then there are a lot of
convolution mathematical algorithms that allow, although the eye is not a camera,
They allow making an approximation of each eye with that PSF, what the resulting image would be like.
If a point, instead of being a point, has the shape of a star, then how is the resulting image.
Many things come out of here that many people will know, especially the photography part,
Very interesting is the defraction limit. If you have an optical system, if the aperture
were infinite, because you would have a resolution that is not limited by anything, but if you have a
opening, such as that of the eye, or any optical instrument that we are capable of conceiving
in our imagination and in reality as well, because it has a physical size there will always be a
maximum resolution that we can reach, because two points, if they are very close,
as through the optical system they are not going to be a point but are going to become a pattern of
diffraction because there comes a time when you are not able to see these two points as two and you see them
as one and what usually happens in photography is that if you know if you know your optics you will know that
If you open the diaphragm a lot and let in a lot of light, you will have the problem that the lenses
the edge because they tend to have more aberrations so if you open the image a lot it will be worse than if
and if you close a lot, you’re going to get to that diffraction limit and the resolution of
new will be less. So somewhere in the middle is usually the scam point where
the optical system is better. The same thing happens with the eye, at night we don’t see as well
that when there is a lot of light, but when there is a lot, a lot, a lot of light and the iris diaphragm
It is very small, because we do not have the best optical quality in the world either, although that
the brain then does its processing.
we are going to see with each eye a different pattern of diffraction with each eye but hey
It is not far from what others see and in the end, it was concluded that
the stars as a child we can say to simplify a lot because they are drawn with peaks
some peaks that have their explanation in physics and optics this concept of the psf is
It is very powerful and there are many things that start from it, such as calibrating an optical system
or modify the shape of the eye when you are going to have surgery so that it looks good, because everything
that will try to optimize that the image of a point is punctual. Something very simple, but
physically impossible.
And to finish and that you see examples of this, I stop seeing this one. I encourage you to look for one
Hubble or James Webb image of space telescopes. could be searched for
others, but I only leave you homework on these telescopes and you will see how you have that diffraction pattern
in the stars. How these stars have some peaks and if you are curious you can also search
why those beaks have that shape and not another. And nothing else, happy Wednesday and see you tomorrow.
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#stars #drawn #points #Science #Fiction