We can observe satellites with the naked eye, and they will appear like fast-moving stars across the sky. The required conditions: the satellite is large enough and/or close enough, the sky is dark enough, and the satellite is lit by the sun. As a result, the best time to observe satellites is a few hours before sunrise and a few hours after sunset.
Flat-Earthers claim it is impossible to see satellites and use the fact as “proof” the satellites do not exist. In reality, we can observe the satellites even with the naked eye. Apps and websites like heavens-above.com provide us with information on satellite watching opportunities.
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If many satellites provide navigation and surface imagery, why is it challenging to locate the missing MH370 flight?
Satellite navigation, including GPS, is passive. Satellites emit signals, which are processed by receivers —including those on board the MH370— to determine their own locations. The satellites never receive anything from MH370 and cannot determine its location.
Airliners do broadcast their positions using ADS-B. However, at the time of MH370, only ground-based ADS-B stations existed. There were no satellite-based ADS-B receivers yet, and no coverage in the middle of oceans.
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A cellular network consists of several cells. Each of the cells is serviced by a base station operating with a specific frequency. Adjacent cells are each assigned a different frequency. A non-adjacent cell will be able to use the same frequency without interfering.
Flat-Earthers like to tell us that a single satellite can cover an entire country, yet phone operators choose to install base stations everywhere instead. Then they use the fact to “prove” that satellites do not exist. In reality, a cellular network has several advantages compared to one single base station, like a satellite.
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A Sun outage is a disruption of geostationary satellite signal caused by interference of the sun when it falls directly behind a satellite with which a receiver is communicating. Sun outages occur around the March equinox and September equinox.
Flat-Earthers fail to understand how the schedule of a Sun outage depends on the satellite and the receiver’s location. And they use it to discredit the fact. In reality, it is not difficult to visualize how a Sun outage occurs, and it will be consistent with the expectation.
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The DSCOVR satellite orbits around the Lagrangian point L1 between the Sun and Earth. We can say the DSCOVR satellite lies between the Sun and Earth, but it is not exactly between them.
Flat-Earthers discovered images taken by the DSCOVR satellite showing the Moon in front of Earth and a solar eclipse shadow on Earth’s surface. Then they concluded it should be impossible if DSCOVR is really between the Sun and Earth. In reality, the DSCOVR satellite is not exactly between the Sun and Earth. It orbits a point between the Sun and Earth.
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A frame of reference consists of an abstract coordinate system and physical reference points that uniquely fix the coordinate system and standardize measurements. Speed or velocity is relative to a specific 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 like to 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 land if the Earth is rotating. In reality, both the speeds are measured relative to a different frame of reference, and therefore, cannot be compared directly.
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DSCOVR is a spacecraft positioned in the Lagrangian point L1 between the Sun and Earth. It carries the EPIC camera that continuously takes images of Earth in 10 wavelengths from 317nm to 780 nm in rotation.
The Moon can appear in EPIC images, and flat-Earthers incorrectly use the color fringing around the Moon to dismiss the images as fake. In reality, the full-color images are composite of three single-color images taken in consecutive exposures in a one-minute span. As a result, the Moon had shifted in the time span and not perfectly aligned in the different exposures, causing the color-fringing after the images are composited together.
Continue reading “Lunar Transit Images from DSCOVR-EPIC”
Rocket engines produce thrust by releasing mass rearward at a very high speed according to Newton’s third law, not unlike how discharging a fire extinguisher pushes us backward.
Flat-Earthers claim that rocket engines cannot possibly work in space because space if vacuum and there is no air to push against. In reality, it is possible to produce thrust in a vacuum by releasing mass —that we call “propellants”— rearward at a very high speed.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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”