Monday, 22 April 2019

Is the world flat? Is the world round?


About two months ago I revived my Quora account.  This was, in retrospect, a mistake.  The question and answer process is quite hopeless, even when compared to Reddit, and since that time I have got a dailyish email digest of questions and answers.

The first day’s missive wasn’t too bad.  There was a nice mix of physics (what if a grain of sand at ~c hit the Earth? – not much really) and theo-scepticism (ie don’t two passages in the bible contradict each other – perish the thought that the bible might be errant!).  The second was good with some stuff about electrons, quarks and ethics.

The next day there was a trick maths question (written to imply addition, but actually leaving other operations open) and then they kept coming.  The most recent versions are of the ilk “A couple go to the movies, they have two children together, he has three children and she has four, of which two have two children each while his children only have one each.  How many people went to the movies?” – the answer (noting that I have not checked) is two.  The couple went to the movies, not the couple and all their progeny.  The answer for the latter, unasked question is 14.

Similarly, with the farmer who takes X eggs from a population of Y eggs.  He’ll have (in his immediate possession) X eggs.  If he owns all the chickens that laid the eggs and the law says ownership of a chicken means ownership of all eggs laid by that chicken, then he owns (and thus has) Y.  It’s not a maths question, it’s a vagueness of the word “has” question.

Anyways … less than two weeks in there was this question “Is The Flat Earth Society serious?”  Then I started getting more evolution denial questions (How did the Platypus come to be if evolution does not explain it?)  And the flat earth questions became more common and, frankly, more troll-like.  I have to admit that I have looked at a couple, but in the past week or so the headlining topics have been:

Have you ever met a flat-Earther who finally converted to globe Earth? What made him/her change his/her mind?

Can you show an example of some perpendicular object viewed from far away that is seemly tilted due to the curvature of the earth?

Why can't the ISS take a picture of Earth and prove to the Flat Earth Society that Earth is not really flat?

Can someone show me solid proof of the earth being a round planet and not flat, other than NASA and their photos?

Perhaps I am to blame for clicking on a couple of these topics, but I am getting pretty sick of them.  There’s the constant battle between the monkey brained part of me that does want to know what an actress that I don’t know who starred in a show that I didn’t watch looks like today and the rational brained part that knows that 1) even if I did want to see what that actress looks like, I’ll be forced to look at photos I have even less interest in before getting my endorphin reward of seeing what I was seeking, and 2) letting myself be click-baited today allows the machine hone its click-baiting skills to get me again in the future.

So, I am going to purge myself of future interest in the stupid questions by stating here and now that the Earth is flat.
In fact, it’s very, very flat with a deviation of less than 0.2% from a perfect oblate spheroid and about 0.33% from a perfect sphere.

If the Earth were entirely covered in water, and ignoring the moon, the surface would still be an oblate spheroid because that’s the shape it would assume such that the forces zero out – the combination of gravity and centripetal force due to rotation – which is another way of saying that the surface of the Earth is flat (in terms of spacetime).

What they should be saying, if they aren’t just trolls, is that the Earth is a disk – which it clearly isn’t.

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Part of the “controversy” is that a YouGov survey concluded that a ridiculously high proportion of “millennials” believe that the Earth is flat.  However, the survey was as bad as a Dolly quiz.  “Dolly” was a teenage girl’s magazine which used to have hilariously bad quizzes, so “Dolly quiz” is my go-to smackdown on any poorly worded survey – the YouGov survey is worse than usual.  These, I kid you not, were the survey question and options:

Q: Do you believe that the world is round or flat?
Option 1: I have always believed the world is round
Option 2: I always thought the world is round, but more recently I am skeptical/have doubts   
Option 3: I always thought the world is flat, but more recently I am skeptical/have doubts   
Option 4: I have always believed the world is flat
Option 5: Other/Not sure

So what does “flat” mean (they mean planar, don’t they)?  What does “world” mean (should they not have used the term “Earth”)?  Can’t the Earth be both flat and round (isn’t a standard dinner plate both flat(ish) and round(ish))?  What does “always” mean (I have no clear recollection of what I believed when I was 4 years old, but I am reasonably confident that, when I was two, I had no belief about the shape of the planet, so doesn’t that mean that I have not always believed the Earth is spherical)? Why skip between “believed” and “thought” (are not thinking and believing distinct)?

I’d have to go with Option 5.  Not only that, I think (believe?) that anyone who answered anything other than Option 5 is either lying or misunderstood the question (as asked).
Of course, you could interpret the question and give an answer based on your interpretation rathe than the question as asked, but people will interpret the question differently.  The Earth isn’t round, it’s an oblate spheroid (oh ok, it’s round if you cut it through the equator, but nowhere else – although the cuts do go from almost perfectly round to mostly round as the cuts get closer to going through both poles).  And it’s very flat.  So strictly speaking it’s more correct to say that the Earth is flat.  Sphericalish, but nevertheless flat.

And then there are the people who’d look at the stupid question and give a stupid answer.  I’d say that, hopefully, the company controlled for that, excluding obviously stupid responses (the question should have been one among many questions – and it clearly was since they were able to split the data up by age, gender, religious affiliation, political affiliation, region, etc), but then this is the same company that posed this stupid question.

What’s really odd is that the analysis implies that the more religious you are the more likely you are to believe the Earth (or world, whatever that means) is flat.  But the more Republican you are, the more likely to are to believe that the Earth is round.  I’m not an expert on American politics, but I would have put the Republicans are more religious than Democrats, so there’s something odd going on there.  Perhaps it’s just that trolls are more likely to do their trolling for the Republicans?

This all just reinforces an opinion that I developed years ago – don’t rely too heavily, if at all, on opinion polls and their like.

Thursday, 11 April 2019

The BGV Theorem Does Not Mean What You Think Means


I’ve addressed the use and misuse of the Borde-Guth-Vilenkin (BGV) Theorem a number of times in the past (The Misquoting WLC, The Eternally Inflated (Multiverse and WLC) and Multiholes in WLC’s Physics Arguments).

The apologetic argument goes a bit like this:  Atheists are terrified by the idea the universe must have begun, because if the universe has not been in existence forever, something must have created it.  The BGV Theorem says that inflation must have had a beginning, so the universe has a beginning, therefore the universe has a creator.  Therefore god.  (Much leaping around fisting the air and yelling “OOH-ya” and “who da man”.)

To be brutally frank, Vilenkin (one of the authors of the theorem) seriously did not help when he wrote:

It is said that an argument is what convinces reasonable men and a proof is what it takes to convince even an unreasonable man. With the proof now in place, cosmologists can no longer hide behind the possibility of a past-eternal universe. There is no escape: they have to face the problem of a cosmic beginning.

Admittedly, he did write a couple of paragraphs later:

Theologians have often welcomed any evidence for the beginning of the universe, regarding it as evidence for the existence of God… So what do we make of a proof that the beginning is unavoidable? Is it a proof of the existence of God? This view would be far too simplistic. Anyone who attempts to understand the origin of the universe should be prepared to address its logical paradoxes. In this regard, the theorem that I proved with my colleagues does not give much of an advantage to the theologian over the scientist. As evidenced by Jinasena’s remarks earlier in this chapter, religion is not immune to the paradoxes of Creation.

But the damage had already been done, there was a paragraph begging to be cherry picked by apologists and they went to town.  (A search on “There is no escape: they have to face the problem of a cosmic beginning” brings up page after page of apologetic nonsense.

As an aside to very interesting video on a universe from ‘nothing’, Vilenkin makes a very clear comment to the effect that the BGV Theorem does not mean what people like WLC want it to mean.  In this part of the video, he very specifically says that the BGV Theorem does not conclude that the universe must have a beginning, it concludes only that expansion must have a beginning.

WLC will need to find a new argument for an absolute cosmic beginning.  Well, he should, but given his track record, it’s likely that he will just ignore inconvenient statements by the people whose arguments he misrepresents.