The directions of up and down are determined from the direction of the Earth’s gravitational acceleration. Up is in the opposite direction, and down is in the same direction as the Earth’s gravitational acceleration.
Flat-Earthers are often seen making fun of this fact. They show us ‘upside down’ pictures taken in the southern hemisphere. They are wrong. To anyone in the southern hemisphere, down is in the same direction as the Earth ‘s gravitational acceleration, the same as anyone in the northern hemisphere.
Continue reading “The Directions of Up and Down”
If Earth’s gravity pulls everything towards the Earth, then how can satellites stay up there and are not falling towards the Earth?
The answer is that satellites orbit the Earth. They have the correct velocity with respect to Earth’s position and gravitational pull.
Continue reading “How Satellites Can Orbit and Stay Up There”
A satellite can be placed in an orbit 35786 km above Earth’s surface, and the satellite will be in motion at the same speed as the rotation of the Earth. As a result, the satellite will appear practically motionless when observed from the surface. Many communication satellites are placed in this orbit, and a satellite dish receiving signals from the satellite doesn’t have to track the satellite.
Flat-Earthers often take the fact that satellites are in motion and most satellite dishes have a fixed direction as ‘proof’ there’s something suspicious about satellites. They are wrong.
Continue reading “Geostationary Satellites”
The Mississippi River never flows uphill, or in other words, ascend to a location farther from sea level anywhere in the Mississippi River basin.
Flat-Earthers often claim that if the Earth is spherical, then the Mississippi River will have to flow uphill to overcome the curvature of the Earth. They are wrong.
Continue reading “The Earth is Spherical and The Mississippi River Never Flows Uphill Anywhere”
Unlike other planets that were found by empirical observation, Neptune was found by mathematical prediction involving Newton’s law of universal gravitation.
Continue reading “Neptune and Newton’s Law of Universal Gravitation”
Some flat-Earthers mentioned the fact that graviton —the mediating particle of gravitation— is ‘not yet observed’. They took this fact as ‘proof’ that gravity does not exist.
Often they would triumphantly show us screenshots of the table of fundamental particles they took from Wikipedia and other sources. In the ‘gravitation’ column, they would point out its mediating particle has not been observed yet. And they would conclude that scientists are aware gravity does not exist, and we all are lied to.
Obviously, they are wrong on all accounts.
Continue reading “The Hypothesized Graviton and Flat-Earthers’ Zeal to Disprove Gravity”
Things fall down because of gravity. The mass of the Earth causes everything to fall down at 9.8 m/s² near the surface of the Earth. This constant is called ‘gravitational acceleration’ and usually denoted by ‘g’.
Most flat-Earthers deny the existence of gravity. According to them, things fall down because of density or buoyancy, not gravity. They are wrong.
Continue reading “Free Fall”
Flat-Earthers mention the curvature of water a lot. According to them, the curve of the water can never be observed, and thus, the Earth is flat.
The problem with such an argument is that they usually conclude that from a very small amount of water. Water in a glass or a bucket will practically look flat. Not because there is no curvature due to Earth’s gravity, but because the water is in such small amount so that the curvature is minuscule and impossible to observe, let alone with the naked eye.
Continue reading “The Curvature of the Water Surface”
The Amazon never flows uphill, or in other words, ascend to a location farther from sea level anywhere in the Amazon basin.
Flat-Earthers often claim that if the Earth is spherical, then the Amazon will have to flow uphill to overcome the curvature of the Earth. They are wrong.
Continue reading “The Earth is Spherical and The Amazon Never Flows Uphill Anywhere”
Water seeks the lowest potential: the position as close as possible to the Earth’s center of gravity. As a result, the surface of the water will have equipotential surface and form an approximately spherical surface that has the same center as the Earth. Every location along the surface has the same gravity potential.
Continue reading “Equipotential: a Property of the Surface of Water”