24

This optical phenomenon is called a 22° halo which is a subset of other halos. This arises from sunlight refracting through hexagonal ice crystals, which can be found in high level cirrus clouds. Light that would otherwise not make it to your eye enters an ice crystal and then exits at an angle of approximately 22 degrees. This produces the arc of light ...


17

This is an interesting phenomenon that I haven't seen before. To start off with a discussion of coronas in general, they are fundamentally caused by diffraction, a form of optical scattering where the path of light from the sun is "bent" as it passes by the edge of a small particle. A simple illustration is case D in this example figure showing ...


10

I am asking why the light of a clear day is not symmetrically changing centered at noon. Trying to attribute this to a single cause misses the point. There are multiple causes. Other than lighting itself (i.e., the Sun angle), most aspects of the atmosphere are not symmetric about noon. The low on a clear day typically occurs right around sunrise (not ...


8

I believe the effects you are talking about are due to scattering by dust and water vapor in the atmosphere. During the night winds are lower and wet areas don't dry out as fast as during the day. Both of these mean that at the start of the day there is less dust and water in the atmosphere at a given location. As the day progresses winds pick up (caused ...


7

There's nothing inexplicable about that photo. It's got a few uncommon features, but nothing unknown. In the image below, I've drastically distorted the brightness curve to make things more obvious: Primary arc. This is the classic "internal reflection" rainbow that you learn about in school. Secondary arc. This one forms when light is reflected twice ...


7

It a supernumerary bow, which results when the droplets that create the rainbow are very small and of nearly uniform size. The droplets need to be small enough so as to make diffraction a significant effect.


7

This optical illusion is due to refraction of visible light due to density gradients near the surface and the fact that the index of refraction in a medium is dependent on the density of the medium. In an atmospheric density gradient light will bend toward the direction of increasing density. When it is cool at the ground and warms up with height this ...


6

The reason why fog bows lack colour, compared to rainbows, is due to the size of the drops of water. Fog is composed of very small drops of water - less than 0.05 mm diameter. Because of this the wavelength of light is critical, with diffraction smearing out colours that the larger drops of water in a rainbow would make.


6

There's no hole. Are you referring to the sky inside the halo looking darker than the sky outside? If so, the same phenomenon, known as Alexander's band, happens with rainbows. The reason is that light can only deviate through a certain range of angles when it passes through the ice crystals that cause the halo. In particular, light can spread outwards from ...


6

Note: All of the links in this answer point to various parts of Les Cowley's excellent Atmospheric Optics site. Les combines photographs, simulated images, and descriptions of the underlying physics to beautifully portray and explain a number of different optical effects in our atmosphere. Note: The imagery on that site is copyrighted. Please do not edit ...


6

What you are seeing are a primary rainbow (rainbow #2 in the linked image), its secondary rainbow (#4), a reflection rainbow (#1), and its secondary (#3). Note well: The linked article called these reflected rainbows, but that is incorrect. A reflected rainbow is yet another atmospheric optical phenomenon that occurs when one sees what appears to be the ...


5

As described here, condensation of cloud particles (i.e., contrail formation) will occur if the mixing between hot and moist exhaust from an aircraft engine and ambient environmental air results in the mixed air exceeding the ice saturation vapor pressure as its temperature changes. A conceptual diagram of this mixing process is shown here, for exhaust (...


4

I take your question as the question about first scattering event, ignoring all the subsequent ones (because they bounce light rays between the top and bottom halves of atmosphere). Also, I'm assuming daylight conditions, like 45° solar elevation. Let's look at a simulation I did using my CalcMySky software. Here's how the first scattering order luminance ...


4

What is happening here? Photoshop! The number of visible satellites plummets towards the middle of the night when more satellites fall into the shadow of the Earth, represented by the dark area on the left of the image. (emphasis added)


3

While the horizontal alignment of ice crystals has been observed in several previous studies listed in the Marshak et al. paper, it is not clear how much ice crystals wobble around the perfectly horizontal position. Determining the range of tilt angles would be very interesting indeed! The reason why ice plates can float with a horizontal alignment is ...


2

This is very unusual and I've never seen it before, though I have seen other rainbow effects such as double and triple rainbows. What they all have in common is a mist of water droplets lit up by the sun. If you have ever seen a dew drop (and who hasn't) you will have noticed that when the sunlight struck it a pretty coloured light came from it. When you ...


2

Why are these patterns of scattered sunlight aligned to the local horizontal and vertical directions? The answer can be found in The New York Times article Light Pillars, a Million-Mirror Optical Illusion on Winter Nights and in The Washington Post's Rare light pillars cast colorful columns into Wisconsin’s night sky says: However, that’s just half the ...


2

this looks like mother of pearl clouds https://en.wikipedia.org/wiki/Polar_stratospheric_cloud they are made of ice crystals very high in the atmosphere the only clouds higher in the atmosphere are noctilucent clouds.if you google mother of pearl clouds there is a lot of pictures and information. as a result of global warming the stratosphere is getting ...


1

This is an excerpt from a paper written on the subject... Why is sunset more reddish than sunrise? By Neerad Tanvi, Bikaner I never considered the settlement of dust at night, but that makes total sense. ... The scattering is also related to the size and quantity of the scattering particles. During the night time the atmosphere is cool and the aerial ...


1

I completely understand what your asking. I too have observed the "difference" in the light of the day. Morning light and afternoon light have a completely different look to them. I have no real way to prove this, but I believe this effect is due to the rotation of the Earth in relation to the Sun's position to the observer. What I mean is this. ...


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