Newton’s cannonball was a thought experiment Isaac Newton used to explain the principle of orbital motion. It was the first explanation of an orbit and still the easiest to understand.
Newton visualizes a cannon on top of a very tall mountain where the air resistance is no longer a factor. As more charge is used with each cannon shot, the speed of the cannonball will be greater, and the cannonball will hit the ground farther and farther. Finally, at a certain speed, it will not hit the ground at all. It will fall toward the spherical Earth just as fast as the Earth curves away from it. In the absence of drag from the atmosphere, it will continue forever in orbit around the Earth.
Continue reading “Newton’s Cannonball”
Many space missions use animations to visualize the state of the missions because it is impossible to record a video of the event. Spacecrafts continuously send telemetry data to Earth informing the status of their mission, and from the data, an animation can be constructed to illustrate the spacecraft’s current situation.
Flat-Earthers accuse that the animations are “proof” that the missions are faked. In reality, the animations are faithful depictions of the missions and are made to visualize the real state of the mission. Animations are used because it is not viable to send another spacecraft only to record a video of the mission. Furthermore, in the cases where the video is available, it is still too difficult for these flat-Earthers to accept reality.
In addition to satellite navigation, mobile phones can also use crowdsourced cell sites and WiFi access points location data. Phones help each other by creating a centralized database of the locations of cell sites and WiFi access points. If satellite navigation is unavailable, then the phones can utilize this database to determine their positions.
Some documentations explain how a phone or device without GPS can determine its location. Flat-Earthers incorrectly use these documentations to “prove” GPS does not use satellites. In reality, there are various methods of determining location, not just GPS. These documentations explain location service using cell & WiFi crowdsourcing, which is different from GPS.
Continue reading “Location Crowdsourcing”
The International Space Station (ISS) was not constructed overnight. It is built gradually, and new components are still arriving after more than 20 years since it was first launched.
The ISS is one of humankind’s greatest achievements, but there is no video showing its construction from start to finish. Flat-Earthers use the fact to “disprove” the existence of the ISS. In reality, the ISS was constructed gradually in years. There is no such video the same way there is none for New York City, for example. It does not mean New York City does not exist. On the other hand, we can find plenty of videos showing the assembly of its specific modules on the Internet. Continue reading “ISS Construction Video”
The Moon orbits the Earth —not the Sun— because the Moon lies well within Earth’s Hill sphere. Hill sphere is the region around Earth where Earth —instead of the Sun— dominates the attraction of satellites.
Flat-Earthers noticed the Sun exerts a stronger pull to the Moon than Earth does to the Moon. They incorrectly concluded that according to science, the Moon should orbit the Sun, then proceeded to use it to discredit science. In reality, they did not account for the centrifugal acceleration resulting from the motion around the Sun, which is one of the factors that determines Earth’s Hill sphere.
Continue reading “Hill Sphere”
In the context of spaceflight, a satellite is an object that has been placed into orbit. A few of these satellites are balloon satellites. These are satellites that are inflated with gas after they have been put into orbit. Other human-made objects are also called satellites, only placed at a much lower altitude and with a very different operating method. These are, in fact, regular high-altitude balloons but providing services traditionally provided by orbiting satellites.
Flat-Earthers deny satellites’ existence, and after they discovered the existence of balloon satellites, they started to use the fact as “proof” that orbiting satellites do not exist. It is a fallacy of proof by example. By the same “logic”, we can use the existence of trucks to “prove” buses do not exist.
Continue reading “Balloon Satellites”
Angular resolution is the minimum separation between distinguishable features in an image. Objects smaller than the angular resolution are indiscernible in the picture. The theoretical maximum angular resolution is determined by the diameter of the aperture of the optical instrument.
Flat-Earthers like to demand images of the lunar landers taken with a telescope as proof that the Apollo Moon landings did occur. In reality, no optical telescope on Earth is large enough to resolve the landers.
Continue reading “Angular Resolution”
Rocket launches have a curved trajectory because their objective is not only to reach space but also to enter Earth orbit. To achieve it, a spacecraft needs to gain a sufficient horizontal speed, parallel to Earth’s surface.
Flat-Earthers claim the curved appearance of a rocket launch trajectory “proves” rockets never reach space. In reality, it is caused by the motion of the rocket parallel to Earth’s surface, perspective effect, and the curvature of the Earth.
Continue reading “Curved Appearance of a Rocket Trajectory”
Fiber-optic communication is a method of transmitting data by sending pulses of light through an optical fiber. These days, the majority of data communication involves a fiber-optic connection. However, other methods of transmitting data exist, including satellites.
Flat-Earthers use the prominence of fiber-optic communication as “proof” of the nonexistence of satellites. Such reasoning is a fallacy of hasty generalization. By the same “logic,” we can “prove” trains do not exist just by showing the existence of cars.
Continue reading “Fiber-Optic vs Satellite Communication”
If a satellite is placed in an orbit 35786 km above the equator, it will be in motion at the same speed as the Earth’s rotation. As a result, the satellite will appear practically motionless from an observer on Earth’s surface. Many communication satellites are in this orbit so that a satellite receiver does not need to track the satellite continuously.
Flat-Earthers often take the fact that satellites are in motion, and most satellite dishes have a fixed direction as ‘proof’ the receivers cannot be pointing to satellites. In reality, it is possible to place a satellite in a geostationary orbit to make it appear in a fixed position in the sky relative to an observer on Earth.
Continue reading “Geostationary Satellites”
Cellular phones communicate with cell base stations, and cannot work without cell base stations nearby. On the other hand, satellite phones communicate with satellites and will work in remote locations as long as there is a line of sight to the satellites.
Cellular phones do not function in a remote location, and flat-Earthers use the fact as “proof” that satellites do not exist. In reality, nobody claimed that cellular phones communicate with satellites. The phones that communicate with satellites are called satellite phones, and they still function in a remote location.
Continue reading “Satellite Phones and Cellular Phones”
Geostationary satellites orbit the Earth with the same rate as Earth’s rotation, 35786 km (22236 miles) above the equator. They are too far and too dim for the naked eye. However, we can observe them using a mounted telescope and a camera.
We can observe many of them by:
- using an equatorial mount,
- aiming the telescope at a star that lies in the orbit’s path, and
- use a camera with a long exposure setting.
Continue reading “Observing Geostationary Satellites”
Google Maps live traffic works by crowdsourcing. It determines the current traffic by aggregating information sent by many phones carried by many different traveling users.
In February 2020, artist Simon Weckert successfully gamed the system and faked a traffic jam in Google Maps. He did that by pulling a cart full of active phones and walking in the middle of roads. Google Maps system thought there were many slow-moving cars on the road and regarded that as a traffic jam. As a result, during Simon’s operation, an empty road appeared as dark red in Google Maps, as if a traffic jam was ongoing.
Flat-Earthers claimed that it proves that satellites do not exist; possibly because they did not know how the system works. It might be that they previously thought the traffic data was obtained directly from satellite imagery. In reality, satellite navigation systems, like the GPS, is very much involved in the system.
Continue reading “Google Maps Live Traffic and Simon Weckert’s Virtual Traffic Jam”
Radio propagation is the behavior of radio waves as they travel from one point to another. As a form of electromagnetic radiation, radio waves are affected by reflection, refraction, diffraction, absorption, polarization, and scattering.
Flat-Earthers assume all radio waves are identical. They invented various “explanations” with the erroneous assumption. In reality, radio waves with different frequencies have different properties and different ways of propagation.
Continue reading “Radio Propagation”
Various pictures showing satellites and space debris around the Earth are visualizations. They are not real photos taken from cameras. These visualizations were created by drawing the objects with sizes far larger than their actual dimensions. If they were drawn to scale, then they all will be too small and cannot be seen in the visualizations.
Flat-Earthers fail to realize that these are visualizations. They think the pictures are presented as real photos. Because we never see satellites like that, they concluded that it was a deception. In reality, these pictures are simply visualization, not actual photos.
Continue reading “Visualization of Satellites and Space Debris”
The International Space Station (ISS) is only about 400 km above the Earth’s surface, only 6% farther from the center of the Earth than the Earth’s surface. Therefore, only a very small part of Earth’s surface is visible from the ISS at any time.
Flat-Earthers like to examine photos of the Earth from the ISS and compare them to those taken from a much farther location. They would take any difference as an inconsistency. In reality, the ISS can only observe a very small part of the Earth, unlike spacecraft much farther away.
Continue reading “View of the Earth from the ISS”
A satellite navigation or satnav system is a system that uses satellites to provide autonomous geo-spatial positioning. Several satellites continuously transmit signals containing their positions and the time when the signal was sent. Receiver units listen to the signals and use the information to calculate their positions.
Flat-Earthers assume that if GPS satellites are used to determine positions, then they should be able to pinpoint the position of a receiver. They are wrong. GPS satellites only transmit signals but never receive signals from the receivers. It is impossible for the satellites to determine the position of a receiver.
Continue reading “How GPS and Other Satellite Navigation System Work”
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”
Troposcatter is a signal propagation method using the scattering phenomenon in the upper troposphere. As the signal pass through the upper troposphere, some of the energy is scattered back toward Earth, allowing the receiver station at the correct location to pick up the signal.
White Alice is a decommissioned troposcatter network in North America. Some flat-Earthers invented the “explanation” that the various satellite-based services we enjoy today are using White Alice. They are wrong. White Alice and other troposcatter networks cannot possibly replace all the services provided by satellites.
Continue reading “White Alice and the Troposcatter Propagation”
NASA has published several pictures of the Earth that are composites. It means the pictures were the result of combining many images into a single picture. In most cases, the source pictures were taken from low-orbiting satellites to obtain higher resolution pictures of the Earth.
Flat-Earthers discovered the photos are composites and claimed to have exposed “yet another evidence” of wrongdoing. They would publish this “findings” everywhere to turn us emotional. They are wrong. Nobody is covering the fact the pictures are composites, and there is no intention to deceive. Information that the photos are composites can be readily found in NASA’s website, far before the claimed “discovery” by flat-Earthers.
Continue reading “Composite Photos of the Earth”