When you ask someone to draw a star, they’ll probably draw something like this
or this or this
Even ignoring the rainbows, this doesn’t seem very scientific
因为我们知道 星星实际上是巨大 火热的等离子“圆球”
since we know stars are actually big hot ROUND balls of plasma
and far enough away that they’re basically just dots.
So why do we draw stars that have points?
The answer is surprisingly simple: we see stars as pointy
Look carefully next time you’re outside on a dark night
or just look at this dot
如果你用全屏观看这个视频 闭上一只眼 放松另一只眼 效果最好
it works best if you make the video fullscreen, close one eye, and relax the other
as if you’re looking at something far away
You should see a pointy, star-like shape!
In fact, it’s not just humans that see pointy stars.
some telescopes see them that way, too!
This is all because light is a wave.
When light from a distant source passes through an opening or around an object
its waves are bounced or bent slightly and interfere with each other
so the passing light picks up an imprint of that opening or object
A straight line, whether it’s a slit letting light through or a rod blocking the light
leaves its imprint by spreading the light out into a perpendicular series of dashes
like what you see when you squint
A cross creates two crossed sets of dashes
circles cause concentric rings
squares spawn a kind of dashed four-pointed star
hexagons dashed six-pointed stars
and the famous double slit experiment gives a series of dashed dashes
My favorite diffraction pattern, though, is probably that of the Penrose tiling
it’s simply gorgeous… not that you see Penrose-tiling-shaped openings very often.
But… the point of all of these imprints is
that they’re the result of a point of light being spread out when viewed through a particular opening or past a particular object.
For example, the Hubble space telescope has four struts that support its small secondary mirror
and their imprint causes the 4-pointed stars in hubble photos
And I bet you can guess the shape of the aperture on the lens that took this picture.
Similarly, the lenses of our eyes have subtle structural imperfections called suture lines
where the fibers that make up the lens meet
These imperfections leave a very particular imprint on light as it passes by
as researchers have confirmed by shining lasers in people’s eyes.
So, even though stars themselves are just tiny round dots
by the time the light reaches our retina, it’s been smeared out into a starlike shape.
Every single eye on earth will see a slightly different starlike smear
depending on the exact nature of its suture lines
your left and right eyes will differ!
What’s weird, though, is that any particular eye sees the same star shape for every star
so while it is actually scientifically acceptable to draw stars like this
if you draw more than one in a single picture, you better make sure they’re all the same shape!
On top of that, since diffraction spreads longer wavelength red light out more than bluer light
这些星形的角事实上是小彩虹 红色在外 蓝色居中
the arms of these star-shapes are actually mini-rainbows with red on the outside and blue in the middle!
再次重申 你可以在哈勃照片 或者更仔细地看一个点光源时看到这一点
which, again, you can see in hubble photographs or if you look even more carefully at a single point of light.
听起来很疯狂 从科学角度说 给星星涂上彩虹色是非常准确的
So as crazy as it sounds, coloring in stars with rainbows is super scientifically accurate
as long as the colors go the right way