Airplane and Earth’s Rotation

An airplane exists on Earth. It has the same motion as the surface of the Earth, including the Earth’s rotating motion. The motion of the airplane itself is measured relative to the surface of the Earth.

Flat-Earthers think that due to Earth’s rotation, an airplane should not be able to fly east or land. They are wrong. The speed of an airplane is relative to the surface. It retains the motion of the Earth and does not need to chase Earth’s rotation.

Continue reading “Airplane and Earth’s Rotation”

Air Distance vs Surface Distance

The cruising altitude of a jet airliner is about 33000-42000 ft or 10000-12800 m. It is very tiny compared to the radius of the Earth of 6378 km. Therefore, the distance measured at the cruising altitude does not differ much compared to the surface distance.

Some flat-Earthers claim that if Earth is a sphere, the distance traveled by a jet airliner would have been multiple times the surface distance. They are wrong. The air distance at 33000 ft is only 0.16% farther compared to the surface distance.

Bottled Water: A Simple Device for Observing the Dip of the Horizon

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”

Frame of Reference

A frame of reference consists of an abstract coordinate system and the set of physical reference points that uniquely fix the coordinate system and standardize measurements. Speed or velocity is relative to a frame of reference. It is possible that two speeds/velocities are measured relative to a different frame of reference and thus cannot be directly compared.

Flat-Earthers would often compare two different speed measurements like an airplane moving at 900 km/h (560 mph) and Earth’s surface near the equator at 1674 km/h (1040 mph). They would conclude the airplane should not be able to catch up with Earth’s surface and would not be able to land if the Earth is rotating. They are wrong. The speeds are measured relative to the different frame of reference, and therefore, cannot be compared directly.

Continue reading “Frame of Reference”