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”
Because of a perspective effect, an observer in space can see more of Earth’s surface if they are farther from Earth.
Flat-Earthers noticed the different visible Earth’s surface in different Earth images and used it to “prove” they are fake. In reality, it is just a perspective effect caused by the fact that the Earth was seen from a different observer distance.
Continue reading “Perspective of Earth Due to Different Observer Distance”
The Saros is a period of 18 years, 11 days, and 8 hours between related eclipses. The eclipses with the same Saros cycle are classified into a Saros series which is numbered for identification.
Flat-Earthers claim the usage of the Babylonian term Saros “proves” that eclipses are predicted using ancient Babylonian technology. In reality, the Saros is now used to classify related eclipses. For example, the solar eclipse on August 21, 2017 is the 22nd member out of 77 in the Solar Saros 145.
The term Saros was first used in association with eclipse by Edmond Halley in 1691. The Babylonians never used the term Saros to describe eclipses. And the numbering system of the Saros series was created by G. van den Bergh in 1955.
Continue reading “The Saros Cycle and Saros Series”
Saros is a period of 6585⅓ days separating the occurrence of two eclipses. One Saros after an eclipse, a similar eclipse will occur. The eclipses that belong to the same cycle are grouped in a Saros Series.
Flat-Earthers claim that we can only predict eclipses using the Saros Cycle. In reality, it is impossible to determine many characteristics of an eclipse from its Saros Cycle alone.
Continue reading “Saros Cycle and Prediction of Eclipses”
Using the current computing power, predicting eclipses is usually done iteratively. We determine the position of the Sun and the Moon at a time and calculate their elongation to determine if an eclipse happens. This same procedure is then repeated many times, each for a different time.
Flat-Earthers insist that nobody can predict eclipses from the position of the Sun and the Moon. They incorrectly believe NASA used the ancient Saros cycle to predict eclipses by calculating the interval between eclipses. A tiny Python script can easily debunk it.
Continue reading “Predicting Eclipses Does Not Require the Saros Cycle or NASA’s Involvement”
The Lunar Reconnaissance Orbiter (LRO) is a spacecraft orbiting the Moon. It is equipped with a high-resolution camera that has captured photographs of Apollo landing sites.
We often observe flat-Earthers demanding NASA to prove the Apollo missions with recent photos of the landing sites, and NASA has provided just that. However, this too will not be enough for them to accept that the Apollo missions did occur.
Continue reading “Images of the Apollo Moon Landing Sites Taken By LRO”
NASA lost the telemetry tapes containing the recording of the raw video data transmitted by the Apollo 11 mission. However, all the data was also safely recorded elsewhere.
Flat-Earthers make a big deal out of this incident to discredit the Apollo mission. In reality:
- The only lost data was the raw video before the conversion to NTSC for TV broadcasting.
- Only the raw data was lost, but there are other recordings of the same footage.
- Apollo missions other than Apollo 11 were not affected.
- There is no lost video that has never been seen.
- NASA discovered high-quality recordings of the same video.
Continue reading “The Missing Apollo 11 Telemetry Tapes”
The Apollo Lunar Module needed to be as light as possible. It would also operate only in a vacuum and did not have to be sturdy or aerodynamic. To reduce weight, its hull was covered with various insulation blankets instead of rigid heat shields.
Flat-Earthers often ridicule the shape of the lunar module of being flimsy. In reality, there is no requirement to look pretty. The flimsy-looking things are just the insulation blankets. The actual hull underneath them provides structural support.
Continue reading “Apollo Lunar Module Insulation Blankets”
Flat-Earthers compared the apparent size of the ISS and an airplane that appeared in photographs and then incorrectly concluded that the ISS could not be 410 km above us. Their mistake was equating altitude with distance and failing to account for both the ISS’ and the airplane’s downrange distance.
If an airplane is at an altitude of 12 km, it does not mean its distance from an observer is also 12 km. Its altitude and distance are equal only if the airplane is directly above the observer. If the plane is not directly above, then its distance is greater than its altitude.
Continue reading “ISS Size Compared to an Airplane in a Photograph”
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.
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”
Earthrise is a photograph of Earth taken from lunar orbit during the Apollo 8 mission, seven months before the first Moon landing by the Apollo 11 mission. President Nixon hung a copy of Earthrise on the wall next to his desk in the Oval Office.
The picture of Earthrise was prominently visible during news coverage of President Nixon’s call with Apollo 11 astronauts on the lunar surface. Flat-Earthers find it strange Nixon already had the photo hung on the wall when the mission was still ongoing. These people are unaware that there are already several Apollo missions before Apollo 11, and Apollo 11 was only the first to land on the Moon.
Continue reading “Earthrise in President Nixon’s Oval Office”
At the longest zoom, the Nikon P1000 has a field of view of 0.2°, which is equivalent to 1342 km at the Moon’s distance.
Flat-Earthers zoomed their Nikon P1000 at the Moon and claimed that they could not find flags and landers from the Apollo missions. In reality, the smallest objects on the lunar surface they can observe using their cameras are large city-sized objects.
Continue reading “Zooming at the Moon”
Radio waves travel at the speed of light; it takes 1¼ seconds to cover Earth-Moon distance. It is the reason in the Apollo missions after Houston says something, the response from the astronauts on the Moon will arrive only after 2½ seconds.
Some presentations of the Apollo missions are edited to cut out the gaps created by the delay, and flat-Earthers use them to dismiss the Apollo missions as fake. However, in the actual audio recordings and the transcripts, the delays are there.
Continue reading “Communication Delays in Apollo Missions”
The Blue Marble is an image of Earth taken by the crew of the Apollo 17 spacecraft on its way to the Moon. It was taken from a distance of 29000 km from Earth’s surface.
Flat-Earthers dismiss it by incorrectly asserting that the image covers a too-small area of Earth’s surface, due to their failure to account for the maps’ distortion.
Continue reading “Blue Marble and the Visible Area of Earth’s Surface”
Richard Garriott is a video-game developer and entrepreneur who is also an avid magician. In October 2008, he flew to the ISS onboard a Soyuz rocket as a private astronaut. During his time on the ISS, he performed several magic tricks.
One of his magic tricks involves a hammer that floats and a card that seems to fall as if it is pulled down by gravity. Flat-Earthers were unaware it was a mere magic trick and wrongly assume it demonstrates things are falling in the ISS, despite other objects in the scene that float.
Continue reading “Richard Garriott’s “Pocket of Gravity” Magic Trick”
After the Apollo moon landings, we continue launching missions to the moon, but with uncrewed spacecraft. The Apollo program was not entirely a scientific mission. It also served as a political mission due to the Cold War. We can research a lot of things about the moon without risking human lives by sending them to the moon.
Flat-Earthers claim that there have not been any missions to the moon after the Apollo missions, and they conclude that the Apollo missions were fabricated. In reality, we continue sending spacecraft to the moon to this day.
Continue reading “Missions to the Moon, Post-Apollo”
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”
Flat-Earthers often challenge us to provide a video of a rocket launch that was taken from the rocket itself, without interruption from launch to reaching space, as if it would convince them to accept that it is real and the Earth is a sphere.
The launch video of the 2001 Mars Odyssey mission easily fulfills their demand. But whether they can manage to accept the reality that Earth is a sphere is entirely another matter.
Continue reading “2001 Mars Odyssey Launch Video”
In making mathematical models, physicists often remove real-world details that have little influence over the final results for simplifications. In flight-dynamics, it is often perfectly adequate to assume Earth is flat & non-rotating, even if the final aircraft will be flying over spherical & rotating Earth.
Flat-Earthers claimed to have exposed ‘a secret document’ from NASA, saying that Earth is flat & non-rotating. In reality, the document is simply a derivation of a flight dynamics problem, assuming flat and non-rotating Earth, which is a common assumption made to simplify flight models. It does not imply the Earth is flat and non-rotating.
Continue reading “Flight Dynamics: the Assumption of Flat & Non-Rotating Earth for Simplification”