The Sun emits sunrays to every direction. But as the Sun is very far, the sun rays that reach us are practically parallel. To an observer on Earth, the rays of light coming from the Sun form a maximum angle of about 0.53°. They are practically parallel, but not perfectly parallel.
Flat-Earthers often question the fact we say sun rays are parallel, but in any diagram of an eclipse, they are drawn at an angle. They merely confuse practicality with perfection. Sunrays are practically parallel, but they are not perfectly parallel.
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The amount of obstruction of a distant object that is caused by Earth’s curvature depends on:
- The distance of the object.
- The height of the observer.
- The height of the object.
- The magnitude of atmospheric refraction.
Flat-Earthers like to use the visibility of a distant object to prove Earth’s curvature does not exist. Very often, they failed to account for observer’s height and atmospheric refraction, or make other mistakes, like unit conversions errors, distance calculation errors, etc. Once all are considered for, and mistakes are fixed, everything will be consistent with spherical Earth.
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During an equinox (March 20 and September 22-23), the Sun is directly above the equator. If we are on the equator, an upright stick will not have a shadow in the middle of the day.
On any other location, the angle between the stick and the direction of sunlight will be the same as the observer’s latitude.
This fact can only occur if the Earth is a sphere, and only if the Sun is very far relative to the size of the Earth.
Continue reading “The Angle of a Shadow During Equinox”
The Schiehallion experiment was an experiment to determine the mean density of the Earth. It involved measuring the tiny deflection of a pendulum due to gravitational attraction from the mountain of Schiehallion, Scotland. The measured deflection was 11.6″ or 0.003°.
Flat-Earthers claim that it is impossible to demonstrate gravity and that it is evidence gravity does not exist. They are wrong. The Schiehallion experiment was one of the first practical experiments of gravity done on Earth.
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In the 11th century, Al-Biruni successfully determined the radius of the Earth by measuring the dip of the horizon from the top of a hill.
In the 21st century, we can easily repeat the same experiment with practically no effort. All we need are a smartphone and an opportunity to observe the horizon from a high altitude, like during a flight.
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The distance to the Sun was first determined with a good accuracy from worldwide observations of the transit of Venus. A transit of Venus is a phenomenon where Venus passes in front of the Sun. By measuring the time Venus spends crossing in front of the Sun from two or more locations on the surface of the Earth, it is possible to calculate the distance to the Sun.
Flat-Earthers insist that it is impossible to determine the distance to the Sun in the globe model because sun rays are practically parallel. They are wrong. Using simple geometry, the distance to the Sun can be determined from the observations of the transit of Venus.
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The apparent size of the Sun is practically constant throughout the day. This can only happen if the Sun is practically at the same distance all day.
In the flat-Earth model, the Sun is close to the surface at the distance of about 5000 km (3500 miles). The Sun is supposed to be moving in a circle, and it completes the circling motion once in a day. This fact should cause the Sun’s apparent size to change during the day. But it does not happen. The Sun’s constant apparent size is evidence that the flat-Earth model is wrong, and that the Sun is very far away.
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Seismic waves are waves of energy that travel through the Earth’s layers and are a result of earthquakes, volcanic eruptions, massive landslides and large human-made explosions. Some types of seismic waves travel through the interior of the Earth and are detected by seismic stations on the other side of the Earth. By analyzing the types of waves that are received by seismic stations, we can determine the interior of the Earth.
Flat-Earthers are often seen saying that it is impossible to determine the interior of the Earth as nobody has gone there. They are wrong. Using seismology, we can determine the interior of the Earth without going there physically.
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Sunlight can be broken into its constituent colors using a prism. The colors are the optical spectrum of the Sun. They are the same colors on rainbows. On careful observation, the spectrum is not perfectly continuous, but it has dark lines scattered over the entire spectrum. It turned out that from the lines, we can tell the composition of the Sun without physically getting there.
Some flat-Earthers think that it is impossible for us to determine the composition of the Sun, as it is impossible for anyone to visit the Sun without getting roasted in the process. They are wrong. The composition of the Sun can be determined from the spectral lines, or more specifically for the Sun: the Fraunhofer lines.
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Anyone who is in the northern hemisphere can observe the star Polaris, located very close to the north celestial pole. As a result, when observed casually, Polaris appears practically stationary in the same position.
Flat-Earthers claim that the fact Polaris appears stationary as ‘evidence’ that the Earth is stationary: if the Earth is in motion, then Polaris should appear in motion too. They are wrong. Polaris appears stationary because it is very far and its motion can’t be visually observed in the scale of a human life.
Continue reading “The Distance to Polaris”