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”
In the context of spaceflight, a satellite is an object that has been intentionally placed into orbit. A few of these satellites are balloon satellites. They are satellites that are inflated with gas after they have been put into orbit. There are also other human-made objects which are also called satellites, only placed in a much lower altitude, and with a very different operating method. These are actually regular high altitude balloon, but providing services traditionally provided by orbiting satellites.
Flat-Earthers deny the existence of satellites, 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 the fallacy of hasty generalization. Using the same “logic” they are using, we can use the existence of trucks to “prove” buses don’t exist.
Continue reading “Balloon Satellites”
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”
The surface of the Earth close to the equator is moving at the speed of about 1670 km/h due to Earth’s rotation. To take a sharp picture of the Earth with the resolution of 10000×10000 from a stationary position in space, it would require the shutter speed faster than 2.7 seconds. It is not difficult at all to take a sharp picture of the entire Earth without perceivable motion blur.
Flat-Earthers claim that it should be impossible to take a sharp picture of the Earth from space due to the speed of Earth’s rotation. To them, the fact that a photographer cannot take a sharp photo of a speeding race car from the sidelines (they actually can) tells us it should be impossible to take a sharp picture of the Earth moving at 10× the speed.
They are wrong. Motion blur is caused by the angular speed of the object relative to the camera, not from its absolute speed. The vast distance required to take a photo of the Earth results in a very low angular speed, making it not difficult at all to take sharp images of the Earth.
Continue reading “The Lack of Motion Blur in Earth Photos”
A satellite in a high enough orbit can remain operational for a very long time because in space there is practically no air resistance. This is a situation that never occurs in our everyday life. A car requires a constant consumption of fuel to keep running, but a satellite can remain in motion without consuming any fuel because there’s practically no force stopping it.
Flat-Earthers claim that satellites cannot stay up there for such a very long time because ‘we never refuel any satellites.’ They are wrong. In space, there is practically no drag, and satellites only need to consume fuel to adjust their speed periodically.
Continue reading “Orbital Station-Keeping”
Flat-Earthers reject the existence of satellites. They are wrong. To prove the existence satellites, we can attempt to take pictures of the ISS when an ISS transit happens, or the ISS passes in front of the Sun or the Moon.
Continue reading “Observing the ISS from ISS Transits”
Most combustion engines work with oxygen from Earth’s atmosphere as its oxidizing agent in the combustion process. But in the case of rockets, there’s no oxygen in space. It would have to bring the oxidizer in addition to its fuel or use monopropellant which doesn’t require an oxidizer.
Flat-Earthers claim rockets should not be able to work in space because there’s no oxygen in space. They are wrong. The lack of oxygen in space is merely an engineering problem which is not impossible to solve. Rockets are engineered to carry its oxidizer or utilize monopropellant which does not require an oxidizer.
Continue reading “Rockets and the Lack of Oxygen in Space”
Drag is a force acting opposite to the relative motion of an object moving with respect to a surrounding fluid. The higher the density of the fluid, the higher the magnitude of the drag.
Flat-Earthers claim that it is impossible for satellites to have such high speed. Usually, they would compare the speed of satellites to something like the SR-71 Blackbird, which holds the record as the fastest aircraft. They are wrong. At the altitude where satellites reside, the air density is several magnitudes smaller compared to near the surface, and thus, the drag experienced by satellites is also several magnitude smaller.
Continue reading “Drag”