Zooming In On Distant Boats Does Not Disprove Earth’s Curvature

If a distant boat is not visible, then it is because of at least one of these reasons:

  • Our eyes have limited angular resolution and are unable to resolve the ship at that distance.
  • The atmospheric condition is limiting our visibility.
  • The curvature of the Earth obscures the ship.

Flat-Earthers like to demonstrate that a previously invisible ship at a distance can be made visible by zooming in. They would use it to disprove Earth’s curvature. They are wrong. There are reasons other than Earth’s curvature that can obscure a distant boat.

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Crow’s Nest on Ships

A crow’s nest is a structure in the upper part of the ship, especially old-fashioned ones. It is used as a lookout point and positioned high above to increase visibility over the curvature of the Earth.

On the deck of a ship 4 m (13 ft) above the surface of the ocean, an observer can spot a 20 m (66 ft) high ship from at most ±25 km (16 mi). On the other hand, from a 35 m (115 ft) high crow’s nest, an observer will be able to spot the same ship from ±40 km (25 mi) away.

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Sextant: Determining Latitude from The Positions of the Stars

Long before GPS, navigators used a device called ‘sextant’ to determine the angle of a celestial body. From that data, the latitude of their current location can be determined.

This can only happen if the Earth is spherical.

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Why Tides Do not Occur on Lakes or Other Bodies of Water

All the seas and oceans around the world are connected. Water can freely flow between them. That’s the reason tide can occur on them.

On the other hand, lakes are isolated from one to another. Water cannot freely flow between them. That is the reason tide in meaningful amount cannot occur on lakes or any other bodies of water.

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