In a minute physics video about the shapes of stars, it mentions that stars in the night sky appear star-shaped due to imperfections in our eyes known as suture lines which cause diffraction.

Then why does the Sun looks round? In a source it is written its because the Sun is too close to Earth. But why does the Sun's closeness to Earth matter?

  • 2
    Please give a link to the Minute Physics video. – Farcher Sep 20 at 12:52
  • I am asking why that does not happen to the sun? It seems perfectly round to use. Why diffraction does not occur in case of the sun? – Sujal Koirala Sep 20 at 14:48
  • here is the video – Sujal Koirala Sep 20 at 14:51

Distant stars are small, Sol is big

Because distant stars are small in our field of vision... they are point-sources of light. Point-sources of light are easily affected by sutures and other imperfections in the eye.

Sol however is not a point-source of light in our field of vision. Sol is huge when comparing its apparent size to its distant siblings. And objects that are large in our field of vision are not affected in the same way by imperfections in the eye.

  • 1
    Regarding the edits that were made: I have reverted to a smaller headline. I will use a headline however, because headlines are a great help to readers to quickly get the gist of an answer. Also our nearest star does not have a name, nothing that requires us to call it by one or another. As the link I put in shows, Sol is a somewhat poetic name, and I quite like it, so I will use it because 1) it is clear enough that people will understand what I mean and that I am referring to "our" star and 2) it is more beautiful and poetic than "the sun". – MichaelK Sep 20 at 15:20
  • I did not realize your answer was of a poetic nature. – Stéphane Rollandin Sep 20 at 15:40
  • Also, if the gist of your answer if that stars are small while the sun is big, it's just plain wrong. – Stéphane Rollandin Sep 20 at 15:44
  • 1
    Lousy reference. The English name of the star about which our planet orbits is the Sun, with an upper case S. While there are very large number of suns and moons in the universe, there is only one Sun, and only one Moon. – David Hammen Sep 20 at 15:56
  • 1
    "Sol" and "Luna" seem like good names to me. They're clearly recognizable and mitigate the ambiguity that can come from "Sun" and "Moon". I see no advantage in insistence that "Sun" and "Moon" continue to be used. – Nat Sep 20 at 17:30

The stars are very distant objects. As the the distance between our eyes and object increases the objects appear smaller. And the stars are at infinite distance so they appear pointlike sources of the light. If they were of the size of smaller celestial bodies like moon, earth or neptune they would not be visible to our naked eyes, but they are of the size of sun or way more bigger than that.

Your Answer


By clicking "Post Your Answer", you acknowledge that you have read our updated terms of service, privacy policy and cookie policy, and that your continued use of the website is subject to these policies.

Not the answer you're looking for? Browse other questions tagged or ask your own question.