Sunset on a flat earth

Earlier, I wrote a post on why people know that the earth is round. Evidence such as star movement, the obscuring of distant objects by the earth’s curvature, and aircraft flight times shows that the earth is not flat:

In this post, I want to temporarily put on the “hat” of a flat-earther. They claim that the sun is a “spotlight” which travels across a circular flat earth like this:

That is at least a well-defined model, crazy though it might be, and therefore can be tested. Here is a computer render of the spring sun at sunset on that assumption (as seen from, say, San Francisco, at the moment that the sun disappears from view):

Three obvious problems with the flat-earth model are visible in this picture:

  • The sun is much too small: only 40% of its noontime diameter (because it is 2.5 times as far away as at noon)
  • The sun appears oval, rather than circular, because the “spotlight” is being seen obliquely (click to zoom if you can’t see the shape)
  • The sun is much too high in the sky (24° above the horizon)

In reality, of course, the sun at sunset is a circular disk that gradually slips under the horizon. Oops. No, the earth is not flat.


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Australians know that the world is round

Following up on my earth-measuring post, people have known for more than 2,000 years that the earth is round. In 350 BC, Aristotle wrote “The evidence of the senses further corroborates this [that the earth is spherical]. How else would eclipses of the moon show segments shaped as we see them? As it is, the shapes which the moon itself each month shows are of every kind straight, gibbous, and concave-but in eclipses the outline is always curved: and, since it is the interposition of the earth that makes the eclipse, the form of this line will be caused by the form of the earth’s surface, which is therefore spherical. Again, our observations of the stars make it evident, not only that the earth is circular, but also that it is a circle of no great size. For quite a small change of position to south or north causes a manifest alteration of the horizon. There is much change, I mean, in the stars which are overhead, and the stars seen are different, as one moves northward or southward. Indeed there are some stars seen in Egypt and in the neighbourhood of Cyprus which are not seen in the northerly regions; and stars, which in the north are never beyond the range of observation, in those regions rise and set. All of which goes to show not only that the earth is circular in shape, but also that it is a sphere of no great size: for otherwise the effect of so slight a change of place would not be quickly apparent.” (On the Heavens, II, 14).

Around the year 700, Bede wrote “We call the earth a globe, not as if the shape of a sphere were expressed in the diversity of plains and mountains, but because, if all things (terrestrial) are included in the outline, the earth’s circumference will represent the figure of a perfect globe. Hence it is that the stars of the northern hemisphere appear to us, but never those of the southern; while on the other hand, the people who live on the southern part of the earth cannot see our stars, because the globe obstructs their view.” (De Natura Rerum). Australians verify his statement about stars every night.

I have commented previously on how the medieval poet Dante described time zones on a round earth:

In more recent times, we have pictures from space:

Aristotle and Bede mention the stars. Not only do the visible stars vary with latitude, but in the Northern Hemisphere they rotate around Polaris, while in the Southern Hemisphere they rotate around the South Celestial Pole, as in this photograph taken in Chile:

Sailors at sea have long known that the earth is round. From a vantage point 20 metres above sea level, one can see a complete ship 17 km away. Beyond that, the distant ship goes “hull down,” and only the upper parts of it are visible (from 34 km away, the lower 20 metres of a distant ship will be hidden). Closer to sea level, the distance is much less. This photo, taken in Spain by “Santifc,” shows the phenomenon (and similar observations can be made at some Australian beaches):

And, of course, the aircraft flight times to and from Australia can only be explained by the fact that the earth is round:


Silly Season in the Sky (again)

It’s apparently time for lunatic end-of-the-world prophecies again. The latest relates to a “great red dragon” in the sky (a reference to Revelation 12):

Turns out that this is a double image of Saturn, taken way back in 1983 by the Infrared Astronomical Satellite (IRAS). Saturn was then at RA 13h45m18.2s, DEC -08d13m07s.

It’s a false-colour image (i.e. not red at all), being taken at 100 microns, in the infrared region of the spectrum. But with enough spin, apparently it can be made to sound scary.

In the final version of the infrared sky survey, this artefact was blacked out, since it doesn’t reflect any actual stellar infrared sources (just a planet that moves around). Of course, that removal got the conspiracy-theory nutters going.


When the towers fell


The World Trade Center towers (photo: Carol M. Highsmith)

I continue to see bizarre and ill-informed conspiracy theories on the Internet about the 2001 collapse of the World Trade Center towers (above). This is in spite of the detailed investigations of, and voluminous reports on, the event.


Steel softens at temperatures well below the melting point of 1400°C

In fact, it has long been known that structural steel buildings like the World Trade Center can collapse due to fire. In 1967, the structural steel roof of McCormick Place in Chicago collapsed because of softening due to a fire. This collapse began only about 30–45 minutes after the fire was reported.


The World Trade Center under construction (photo: Eric Shaw White)

In the case of the World Trade Center, this fundamental problem with structural steel was combined with building-specific design flaws. Still, in my view, concrete construction is simply safer. Concrete resists fire far better than steel, and locating fire escapes inside a thick concrete core assists evacuation, should that be needed. The 9/11 conspiracy theories are just silly, though.


A concrete tower under construction in Australia (photo: Erin Silversmith,)


Conspiracy theories in the USA

In 2013, Public Policy Polling (PPP) surveyed 1,247 registered American voters on a range of conspiracy theories. This blog post looks at six of them:

Conspiracy theory Believe Disbelieve Not sure
Roswell 21% 47% 32%
Vaccines/autism 20% 46% 34%
TV mind control 15% 70% 15%
Moon landing fake 7% 84% 9%
Chemtrails 5% 87% 8%
Lizard people 4% 88% 7%

The Roswell theory is that a UFO crashed at Roswell, New Mexico in 1947, and the US government covered it up. In fact, we now know that what they covered up was a classified military balloon project.

Many people, sadly, believe in a Vaccines/autism link, thanks to some fraudulent research. Several large-scale studies prove conclusively that there is no such link (for example, a Danish study of 537,303 children).

Many people believe in TV mind control, i.e. that the government and/or media secretly adds mind-controlling signals to TV broadcasts. Some wear tin foil hats (above) to protect themselves from this imaginary danger.

Many also believe, implausibly, that the 1969 NASA Moon landing was fake. This idea has been thoroughly debunked, and it was never very believable. For one thing, it assumes that hundreds of thousands of people around the world (including many Australians) would have kept the conspiracy a secret.

Also popular is the Chemtrails theory, that contrails seen in the sky are actually chemicals being sprayed by the government for sinister reasons. In fact, there is no evidence to support the idea, it’s ridiculous to believe that conspirators would spray themselves, the physics of contrails is well understood, and contrails have been around since World War II (as the 1943 photo above by Sgt. Stanley M. Smith, USAF proves).

Finally, the Lizard people theory is that the world is secretly run by shape-shifting lizards in human form. I cannot even imagine why someone would believe that.

The chart below shows the breakdown of the PPP results by sex, political party, race, and age (click to zoom):

This chart only shows the percentages who are sure of their belief in these conspiracy theories. The substantial “Not sure” numbers (in the table at the top of this post) are not included. The chart below shows how much more likely different groups are to believe a theory than average. The most gullible groups seem to be people under 30 and “other races” (i.e. not Hispanic, White, or African-American). African-Americans seem quite sceptical of many of the six conspiracy theories listed here (although other conspiracy theories are accepted – see the complete survey results). Republicans are slightly more likely than Democrats (14% vs 11%) to believe the six conspiracy theories listed here.

Overall, the results suggest that many people in the USA lack the ability to accurately evaluate the truth or falsity of a statement. This does not reflect well on the educational system there. That said, I’m not sure that things are actually better here in Australia.