The Change of Constellations

Featured Video Play Icon

We can’t observe stars moving relative to each other, and the shape of constellations looks the same every night. The reason is not that stars are stationary, but their motions are very slow and cannot be observed over the timescale of human life.

Flat Earthers claim that the fact constellations don’t appear to change as proof the Earth is stationary. They are wrong. Stars have proper motion, but they can only be observed using precise instruments over a long time. Constellations do change, but the change is slow and cannot be perceived over the timescale of human life.

Continue reading “The Change of Constellations”

Total Lunar Eclipse, Drawn to Scale

Any diagram showing two or more celestial bodies is almost never drawn in the correct scale. The reason is that in most cases, any two celestial bodies are spaced too far away relative to their sizes. It is just not possible to draw them in the correct scale and still effectively describes what we want to explain. We don’t have much choice other than drawing them not to scale.

The perpetrators of flat-Earth disseminate the allegations that the diagrams were drawn not to scale because of evil intentions, and not because of legitimate technical reasons. Some people don’t understand this and fell victim to flat-Earth indoctrination.

Continue reading “Total Lunar Eclipse, Drawn to Scale”

Orbital Inclination: The Reason an Eclipse Does Not Occur Every Month

The orbit of the Earth and that of the Moon are not perfectly aligned in the same plane. The orbital plane of the Moon is inclined 5.145° from the Earth’s orbital plane. This is the reason an eclipse does not happen every month.

Sometimes we see flat-Earthers claim that an eclipse should happen every month. But it does not, and they take that as ‘evidence’ of the failure of modern science to explain the occurrence of an eclipse. Their mistake is that they don’t account for the orbital inclination.

Continue reading “Orbital Inclination: The Reason an Eclipse Does Not Occur Every Month”

Total Solar Eclipse, Drawn to Scale

Any diagram showing two or more celestial bodies is almost never drawn in the correct scale. The reason is that in most cases, any two celestial bodies are spaced too far away relative to their sizes. It is just not possible to draw them in the correct scale and still effectively describes what we want to explain. We don’t have much choice other than drawing them not to scale.

The perpetrators of flat-Earth disseminate the allegations that the diagrams were drawn not to scale because of evil intentions, and not because of legitimate technical reasons. Some people don’t understand this and fell victim to flat-Earth indoctrination.

Continue reading “Total Solar Eclipse, Drawn to Scale”

The Galileo Affair was Never About the Shape of the Earth

Flat-Earthers often bring Galileo into the discussion. They treat him as a ‘villain’ who supported the spherical Earth but unable to prove it as he failed to demonstrate the occurrence of stellar parallax.

They are wrong. The Galileo affair was in fact not about the shape of the Earth at all. It was about geocentrism vs. heliocentrism. Everyone involved already knew that the Earth is spherical.

Continue reading “The Galileo Affair was Never About the Shape of the Earth”

Galilean Moons: The First Objects Observed to Orbit Another Object

Jupiter possesses four large moons: Io, Europa, Ganymede, and Callisto. These are called the Galilean Moons. They are easy to observe and the first objects found to orbit a planet other than the Earth.

Flat-Earthers are often seen demanding proof that an object can orbit another object. All they have to do is to use a telescope to observe Jupiter and its Galilean moons.

Continue reading “Galilean Moons: The First Objects Observed to Orbit Another Object”

The Distance to Polaris

Anyone who is in the northern hemisphere can observe the star Polaris, located very close to the north celestial pole. As a result, when observed casually, Polaris appears practically stationary in the same position.

Flat-Earthers claim that the fact Polaris appears stationary as ‘evidence’ that the Earth is stationary: if the Earth is in motion, then Polaris should appear in motion too. They are wrong. Polaris appears stationary because it is very far and its motion can’t be visually observed in the scale of a human life.

Continue reading “The Distance to Polaris”

Annual Stellar Motion: Evidence of Earth’s Orbit Around the Sun

In each day, we can observe stars drift about 1° in their movement around the celestial pole. In a month, they will appear to have moved about 30° when observed at the same time in the night. And in a year, stars are back to their original positions precisely a year before. This annual stellar motion is the basis for the calendar system we are using.

Some flat-Earthers think we see the same star constellations every night. From this assumption, they would conclude the Earth is stationary. But their claim is demonstrably wrong. Continue reading “Annual Stellar Motion: Evidence of Earth’s Orbit Around the Sun”

Stellar Parallax

Stellar parallax is the apparent shift of the position of any nearby star against the background of distant stars. It is caused by Earth’s orbital motion around the Sun. It is so small and hard to observe. Successful measurement of stellar parallax was done only after 19th century.

Flat-Earthers like to think stellar parallax doesn’t exist, and that it is ‘evidence’ the Earth is stationary. They are wrong.

Continue reading “Stellar Parallax”