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Empirical evidence for the spherical shape of Earth - The Stars
The fault in our stars Pseudoastronomy |
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Adding epicycles |
Epicyclists |
Flat-Earthers have made several incorrect observations to claim the Earth is flat. This article refutes claims made by flat-Earthers about the stars.
"But star trail photography proves that the Earth doesn't move!"[edit]

Although the theory isn't necessarily geocentrist (as one can technically still adopt a heliocentric worldview while holding to a belief in a flat Earth), flat-earthers almost always fall into that camp.
One particular claim is that long-duration star trail photographs do not show any movement of the stars other than that caused by the Earth's rotation, the flat-earther's reasoning being that, if the Earth is moving so fast around the Sun, the stars should appear smudged. This claim is symptomatic of all flat-earthers' false assumptions about the distance between us and celestial objects, or their inability or lack of willingness to perform basic math. This is most likely because Spherical trigonometry and astro-trigonometry are exact sciences, which only work in a spherical environment.[1]
For example, let's consider a star trail photograph of the nearest star is taken for 12 hours on a 10,000-pixel-wide camera. The Earth would travel about 1,287,000 km during that time. The nearest naked-eye visible star is Alpha Centauri, which is 4.34 light-years (41 trillion kilometers) away. The star would appear to move 0.018 pixels.[note 1]
The stars in flat Earth model run into all sorts of problems:
- Only a subset of stars is visible, anywhere: There are 2 points to capture star trails and see a star that appears to not move in the sky. These are the famous Polaris in the north and Sigma Octantis in the south. All the stars in the sky rotate around these 2 points which are completely opposite of each other. These are called the Northern and Southern circumpolar stars. Both star trails are made of different constellations. It makes no sense that the northern night sky reveals another 180 degrees worth of stars "due to perspective" as one moves towards southern latitudes.
- Northern stars' trails would appear elliptical: Due to the perspective, star trail photography on northern hemisphere would have circular paths only below north pole. The further from the north pole one moves, the more elliptical the star trails would become. Still, flerfs have zero issue claiming the stars just rotate on different axis depending on latitude, and provide no explanation how that's possible. Or some, like Eric Dubay lie with images that have been stretched to make them appear elliptical. For comparison, here are originals: top left, middle left, bottom left, top right, middle right, and bottom right (video, see 00:11).
- Flat Earth south is in all directions: A person looking at Sigma Octantis from South America would have to be looking in the opposite direction of a person looking at the same star in Australia.
- Southern star trails don't work: The flat-earthers claim the reason Sigma Octantis shows up in all directions, is it takes turns in where it appears. As night time moves around the pizza land, the stars follow it. In other words, in the flat Earth model, Sigma Octantis orbits the north pole. This completely debunks the flat Earth model, as the southern sky star trails show Sigma Octantis remains relatively still.
- Star trails switch direction on southern hemisphere: While star trails in the northern hemisphere show that stars revolve around Polaris counterclockwise, in the southern hemisphere they revolve around Sigma Octantis clockwise. Also, if the camera is looking at the celestial equator, the stars move in parallel straight lines. All of this can be easily explained by the rotation on a round Earth, but it is impossible in a flat Earth "dome". (Even Answers in Genesis admits this much![2])
- Equatorial mounts are needed: Contrary to what flerfs like Dubay quoting William Carpenter have claimed, astronomers have to compensate for the curvature of the Earth in the form of equatorial mounts,
and have done so since the late 1700s. Equatorial mounts are used for polar alignment
in which the axis of rotation of the telescope is aligned with the axis of rotation of the Earth, and rotated in the opposite direction to eliminate apparent movement. On a flat Earth, the polar axis would always be directly perpendicular to the plane of the planet - but a round Earth requires it to be tilted at an angle equal to the latitude of the observer. See Dave McKeegan's video for more in depth explanation why equatorial mounts make zero sense on a flat Earth.



- Stellar parallax exists: Over longer time periods astronomers can observe the apparent movement of nearby stars caused by Earth's orbit around the Sun, though it is quite small. Still, stellar parallax would not exist at all if Earth was the flat immovable place flerfs claim it is. In astronomy, the parsec
is defined as the distance where a star will appear to move back and forth by one arc-second over the course of a year, meaning they measure the precise differences in angles needed to aim a telescope directly at certain star while Earth is on either side of the Sun during its full orbit (for example aiming on the summer solstice and winter solstice and calculating the parallax based on those minute differences). While light-years are what the public generally thinks in when thinking of astronomical differences are far, far more widely used in popular science publications, parsecs are the preferred unit of distance by astronomers due the ease of making calculations with them, acting as a sort of a metric light-year (coincidentally, the ratio between the length of a foot and meter (1:3.28) is almost the same as between the light-year and parsec (1:3.26)).
"But Polaris can be seen from the Tropic of Capricorn!"[edit]
Cries Eric Dubay, parroting Rowbotham's Zetetic Astronomy. To Quote Astronomy magazine's article on the topic:
“”Although Polaris is also known as the North Star, it doesn’t lie precisely above Earth’s North Pole. If it did, Polaris would have a declination of exactly 90°. Instead, our navigational beacon currently has a declination of 89.34°. The difference, 0.66°, would be Polaris’ peak altitude if viewed from the equator, and the latitude south of the equator from which the star would scrape the horizon — if Earth had no atmosphere. But our blanket of air refracts starlight, causing an object near the horizon to appear higher than it really is. Under typical atmospheric conditions, this adds 0.57° to an object’s altitude, so Polaris would barely show up from 1.23° south latitude.
|
—Astronomy Magazine[3] |
So Dubay is just blatantly lying. The burden of proof is on him, and he's free to travel to southern hemisphere to make history by being the first one ever to document Polaris from the Tropic of Capricorn.
"But all stars gradually decline when moving away from the North pole!"[edit]
Says Eric Dubay. Let's see what really happens, first on a hemispherical dome (perfect sphere cut in half), and then a flattened one. In all cases, the observation will be done from the edge of the firmament.
Hemispherical dome
Let's assume the pizza land's radius, i.e. distance from north pole to firmament is 20,000 km. If Polaris is attached to the firmament, it will be visible at
The distance at which Polaris would appear to be at 10° above the horizon, is
The distance at which Polaris would appear to be at 1 arc-minute above the horizon, is
Flattened firmament
But perhaps God doesn't have to care about structural integrity, and the peak of the firmament with Polaris glued to it, is right above the Sun, at 3,000 miles, or 4,828 km. Now, Polaris will be seen at angle. It will not disappear.
The distance at which Polaris would appear to be at 10° above the horizon, is , which is outside the firmament.
The distance at which Polaris would appear to be at 1 arc-minute above the horizon, is which is 43 times further away than the Moon in the globe model.
If you think this problem can be made to go away, by saying the firmament is much larger, then that only raises polaris, and it should appear higher on all latitudes.
"But Sigma Octantis can not be seen with publicly available telescopes!"[edit]
Claims Eric Dubay. Sigma Octantis has apparent magnitude of 5.47. The Limiting magnitude
of stars in dark suburban areas is about 5. Thus, Sigma Octantis is barely visible with naked eye. As explained here, the star can be photographed with roughly 30 second exposure time. Also, telescopes not only zoom in, they also gather more light than the human eye, making objects brighter. Thus, Sigma Octantis that's already barely visible with our tiny pupils, absolutely can be seen with a store bought telescope.
See also[edit]
Empirical evidence for the spherical shape of Earth based on the observations of
Notes[edit]
- ↑ Round earthers are just trying to pull the wool over the eyes of thinking people with math!
References[edit]
- ↑ P.E. Robinson (23 March 2003). "Introductory Astronomy: Parallax, the Parsec, and Distances". YouTube.
- ↑ Flat Earth-Star Trails by Danny R. Faulkner (October 12, 2016) Answers in Genesis (archived from June 9, 2021).
- ↑ Astronomy Staff (Dec. 14, 2018). "Is Polaris visible from the Southern Hemisphere?". Via astronomy.com