On many flights, they would give away leveling devices to all passengers for free, so that everyone would be able to observe the dip of the horizon and proves Earth is a sphere. And as a nice side effect, to quench our thirsts, too!
Such devices are called ‘bottled water’. Using these simple ‘instruments’ on a flight, we can demonstrate that Earth is a sphere.
Continue reading “Bottled Water: A Simple Device for Observing the Dip of the Horizon”
Earth’s curvature is hard to observe from the surface. Even from the altitude of a commercial passenger flight, about 30000-40000 ft, Earth’s curvature is still too small to notice. However, under careful observation, it is not impossible to confirm the curve from the cruising altitude of a jet airliner.
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In the 11th century, Al-Biruni successfully determined the radius of the Earth. He accomplished that by measuring the dip of the horizon from the top of a hill. From the measurements, he was able to calculate the radius of the Earth.
In the 21st century, we can easily repeat the same experiment with practically no effort. We just need a smartphone and an opportunity to observe the horizon from a high altitude, like during a flight.
Continue reading “Al-Biruni’s Method to Determine the Radius of the Earth”
There are two kinds of the horizon:
- Astronomical horizon: the horizon at the eye level.
- True horizon: the line that visually divides the Earth and the sky.
Because the Earth is a sphere, the true horizon always lies below the astronomical horizon, or the eye-level. The angle between them is the dip of the horizon. The higher the observer, the larger the dip of the horizon.
Flat-Earthers claim there’s no dip of the horizon. They are wrong. It is not hard to observe the drop of the horizon and prove the curvature of the Earth.
Continue reading “The Dip of the Horizon”
As the Earth is spherical, the horizon is below the eye-level (or the astronomical horizon). The angle between the eye-level and the horizon is the dip of the horizon. The angle becomes larger as we go higher.
Flat-Earthers often claim that “the horizon always rises to eye-level”, and thus ‘proving’ the flat Earth claim. Despite their insistence to use a water level to ‘prove’ water is flat, the same device can be used to demonstrate the dip of the horizon, proving the water surface has curvature, and consistent with the spherical Earth model.
Continue reading “Water Level Demonstrates The Dip of the Horizon and Proves Earth’s Curvature”