Why Do Stars Twinkle? Supernovas & Photons

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In summary, the twinkling of stars is caused by a combination of spherical aberration and atmospheric conditions, such as pockets of hot and cold air. The atmosphere acts as a lens, causing the light from stars to scatter and appear to twinkle. This effect is not seen in planets, which have a visible disk due to their proximity. Telescopes can also contribute to the appearance of twinkling, with obstructions like spider vanes causing diffraction spikes. Some observatories use flexible mirrors to correct for atmospheric aberrations.
  • #1
alchemist
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why do stars twinkle??

has it got anything to do with the photons emitted from the burning stars? i mean that is it because of the uneven frequency of photons reaching your retina that would cause u so register the lights in an irregular fashion, causing the star to 'twinkle'
what about supernovas, would we be able to see something different from the normal shining lights from the stars if there's a supernova going on??
 
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  • #2
Part of the twinkling is caused by sperical aberration. Spherical aberation is separation of light into it's separate colors by passing through a lens which directs the different colors to a focal line instead of a focal point, with each color focusing at a different point along the line. The atmosphere acts as the lens.
 
  • #3
Also, stars are actively creating light, unlike planets which merely reflect light. One of the ways of knowing if you are looking at a planet or a star is that planets don't twinkle (although they are still effected some by spherical aberration).
 
  • #4
I always wondered about that! By the time light reaches your eye, what does it matter whether it was directly created by a star or happened to bounce off a planet on its way?

What really happens is this: stars are so far away that at the greatest possible magnification, a star still looks like a "point" of light. The visible (to the naked eye) planets are close enough (compared to stars!) that even with only slight magnification, you see a "disk"- and, in fact, your naked eye sees a disk even though it may not be noticeable.

A "ripple" in the sky (sudden temperature or pressure change that changes the refraction index slightly) completely disrupts the single point you see for a star but does not, in general, completely disrupt the small disk of a planet. That disruption is what we see as "twinkling" of stars.
 
  • #5
Telescope

the reason it appears to have lines around it when you look through a telescope is that the lens in the telescope have to be attached by something that blocks some of the light causing the picture to appear in the end to be sparkiling. I believe they are called spider veins. Also you can tell when you are looking at a star versus say a galaxy because a star will have that effect but a galaxy won't.
 
  • #6
In short, the atmosphere is a mess. It is full of pockets of hot and cold air, and since cold air is more dense, light travels "slower" in it, producing all sorts of unpredictable refraction effects. This usually outweighs whatever interstellar obstacles it comes across.

Retina cells are triggered by a minimum of 6 photons, IIRC...
 
  • #7


Originally posted by Tom McCurdy
the reason it appears to have lines around it when you look through a telescope is that the lens in the telescope have to be attached by something that blocks some of the light causing the picture to appear in the end to be sparkiling. I believe they are called spider veins. Also you can tell when you are looking at a star versus say a galaxy because a star will have that effect but a galaxy won't.

Yes. Spider vanes hold the secondary mirrors in some reflecting telescopes (in some types it is attached to optical glass or a lens). The thickness and configuration of these vanes (some are curved some are straight) distorts the image breaking the airy disk (the out of focus view of a star) into segments related to the number and arrangement of the arms. For the most part they have only a minimal effect if the mirrors are good quality and thin spider arms are employed. Personally I use just one (or two one right behind the other) when I build reflecting scopes. I barely notice the distortion.

The inability of a lens to focus all the colors to a single point has a greater effect in refractor scopes often causing coma (a colored glowing haze) to appear to surround bright objects, especially when you try and magnify them too much.
 
  • #8
"Twinkling" is also known to astronomers as "seeing." Some observatories employ telescopes with flexible mirrors that correct for this aberration by responding to feedback from a laser beam parallel to the line of sight. The beam is distorted by seeing, and its affected signal is immediately compensated for by the mirror, reducing the telescope's resolution some ten fold. One must be careful not to blind pilots of passing planes with this substantial laser!
 
  • #9
Obstructions like spider vanes do not cause twinkling. They cause diffraction spikes. The atmosphere causes twinkling.

- Warren
 

FAQ: Why Do Stars Twinkle? Supernovas & Photons

Why do stars twinkle?

The twinkling of stars is caused by the movement of air in the Earth's atmosphere. As light from a star enters the atmosphere, it passes through different layers of air with varying temperatures and densities. This causes the light to bend in different directions, making the star appear to twinkle to the human eye.

What causes a supernova?

A supernova is an explosion that occurs at the end of a star's life cycle. It is caused by the collapse of the star's core, which creates an intense burst of energy that can outshine an entire galaxy. This collapse can be triggered by the star running out of nuclear fuel or by a collision with another star.

How do photons play a role in star twinking?

Photons are the particles that make up light. As these photons travel through the Earth's atmosphere, they are affected by the movement of air, which causes them to scatter and bend in different directions. This scattering is what causes the twinkling effect that we see when looking at stars.

Can different stars twinkle differently?

Yes, different stars can appear to twinkle differently due to their varying distances from Earth, as well as the composition and temperature of their atmospheres. Stars that are closer to Earth will appear to twinkle more because their light has to pass through more layers of atmosphere. Additionally, stars with cooler atmospheres tend to twinkle more than those with hotter atmospheres.

Is the twinkling of stars harmful to our eyes?

No, the twinkling of stars is not harmful to our eyes. In fact, it is a natural phenomenon caused by light passing through the Earth's atmosphere. However, the twinkling effect can make it difficult to observe stars with telescopes, which is why astronomers often use techniques such as adaptive optics to correct for the distortion caused by atmospheric turbulence.

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