Tag: penumbra

The Impossible Eclipse

A selenelion is a rare lunar eclipse where the Sun and the Moon are both visible at the same time. An even rarer form of selenelion occurs if it is a partial lunar eclipse, and the upper part of the Moon is eclipsed. Some call this an “impossible eclipse.”

Flat-Earthers claim that such an eclipse should not be possible to occur because the Earth’s shadow is in the wrong position. In reality, it is possible to happen because the observer is looking slightly downward due to the dip of the horizon and atmospheric refraction.

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Umbra, Penumbra, and Antumbra in an Eclipse Diagram

Light generally travels in a straight line. We can use this property of light to determine the umbra, penumbra, and antumbra part of a shadow by drawing lines from the edges of the light source toward and past that of the occluding object.

Flat-Earthers regard the lines in an eclipse diagram as a violation of the fact that a light source emits light in every direction. In reality, the lines are there only to determine the boundaries of the shadow’s regions in an eclipse diagram.

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Sunlight Creates Umbral Shadow Smaller than the Object Casting the Shadow

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The sun is a huge light source. It is larger than anything on Earth. As a result, the umbral part of a shadow formed by sunlight will always be smaller than the object casting the shadow.

Flat-Earthers assert that a shadow cannot be smaller than the object casting the shadow. They would use that to “disprove” the scientific explanation about the occurrence of a solar eclipse. In reality, it is not difficult to demonstrate that the umbral part of a shadow can be smaller than the object casting the shadow, especially if the light source is the sun.

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Total Lunar Eclipse, Drawn to Scale

Any diagram showing two or more celestial bodies is almost never drawn in the correct scale. The reason is that in most cases, any two celestial bodies are spaced too far away relative to their sizes. It is just not possible to draw them in the correct scale and still effectively describes what we want to explain. We don’t have much choice other than drawing them not to scale.

The perpetrators of flat-Earth disseminate the allegations that the diagrams were drawn not to scale because of evil intentions, and not because of legitimate technical reasons. Some people don’t understand this and fell victim to flat-Earth indoctrination.

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Total Solar Eclipse, Drawn to Scale

Any diagram showing two or more celestial bodies is almost never drawn in the correct scale. The reason is that in most cases, any two celestial bodies are spaced too far away relative to their sizes. It is just not possible to draw them in the correct scale and still effectively describes what we want to explain. We don’t have much choice other than drawing them not to scale.

The perpetrators of flat-Earth disseminate the allegations that the diagrams were drawn not to scale because of evil intentions, and not because of legitimate technical reasons. Some people don’t understand this and fell victim to flat-Earth indoctrination.

Continue reading “Total Solar Eclipse, Drawn to Scale”