Thursday, July 13, 2017

Murphy Responds. And So Do I

More than a year after I published a blog post about his "open letter" to astrophysicist Neil DeGrasse Tyson, Dave Murphy finally got around to discovering it, and made a series of comments. You can see them in full and in context after the blog post, but I decided that, rather than bury my response in the comments section, a new post was warranted, with excerpts from his comments. Starting with:
I am Dave Murphy and I made the video in question, how cowardly of you to make this post without making me aware of it, it's not as if I have made it difficult for anyone to contact me. I certainly hints at the weakness of your position if you resort to sneering at me behind my back. 
So, since Allegedly Dave decided to start right out by calling me a coward for not making him aware of my post (which I never do for anyone) although it has been read nearly 10,000 times as of this writing...well, the gloves are off.

The simple fact is that I am sick to death of these wannabe-rebels who think that they have some arcane knowledge that they are revealing to the rest of humanity to save them from the elite scientists, those people who, in real life, make the world better, safer, and more convenient for all of us as part of their daily work.

So before I begin my refutation of your responses, Mr. Murphy, I'd like to ask you: what have you truly done to make the world a better place today? Pushing urine therapy and the silly notion of a flat Earth do not qualify.

Murphy regales with his qualifications, which consist mostly of software engineering experiences and claimed self-study in the sciences. I won't bore you with that part. But let's skip forward to what he has to say about science:
[Y]ou will note that I said that "All science exists as a theory, that stands until a better theory comes along that more closely follows observation" and as such all views and challenges should be considered for if they are dismissed out of hand, then the scientific method is not being observed. The precedence for my assertion here is Gravity itself, the Newtonian view of gravity stood as established LAW for 200 years until Einstein challenged and overturned it.
 Here Murphy makes the assertion made by all purveyors of nonsense: that all ideas should be considered, else what is being practiced is dogma, not science. Poppycock. Einstein did not, as modern flat-Earthers do, say that gravity doesn't exist, that density and buoyancy can explain everything that gravity is used for. No, Einstein said that Newtonian gravity was pretty close, but that he had a theory that accounted for the discrepancies between observation and theory that had cropped up during those 200 years.

It is also absurd for Murphy to use the history of gravitational theory as his example of the progress of science, since he must, to sustain his flat-Earth notion, discount gravity entirely, a position that puts him squarely at odds with hundreds of years of careful observation by people dedicated to trying to figure out how the world works, and not fit it to a preconceived notion.

He goes on:
Contrary to your statement that flat earthers do not ask real questions about the world, and make predictions that can be tested, we actually do this all the time. For example, we ask:
"How is it that we do not see any evidence of curvature when we stand on the beach and look at the wide expanse of the sea and yet we supposedly see boats go over the horizon as they sail away?" 
So we make the prediction that when we see a boat disappear over the horizon, we should be able to bring it back into view if the earth were flat.
And indeed when we test this and look through binoculars the boat comes back into view, and then when it appears to go over the curve through binoculars we can fire up our trusty Nikon Coolpix P900 camera, zoom in on it and bring it back once again. 
He even invokes the magic Nikon P900, the camera of flat-Earthers everywhere. I don't know whether to congratulate Nikon on the increased sales (I like Nikon; I own a D3300 DSLR, as I mentioned in my last post), or to feel sorry for them for being associated with this nonsense.

Have you ever noticed that in all the videos that flat-Earthers take of "bringing back" boats from the horizon that the boat is not moving away from the observer, but across the field of view? So not going over the horizon at all. Also, the camera always zooms right to the boat, without having to search the horizon for it. That means that the operator of the camera could see the boat before using the zoom. So very definitely not over the horizon.

More patient observers have repeated this experiment, holding the shot longer on ships that actually are moving away from them, and found that the ships do indeed disappear bottom first. Leaving flat-Earthers to invent more bullshit explanations of how that happens when they had just finished claiming that it doesn't happen.

So Murphy then gets around to trying to rebut my answers to his disingenuous questions. I'll only give reminders of the questions; his video "letter" is linked in the original post.

So the first question is, essentially, if the Earth bulges in the middle, why is there land at the equator? His contention is that water is easier to move, so it should be higher than the land at all times. I answered that the process is a gradual one, affecting all parts of the system. He didn't get it:
Mr. Tyson has stated repeatedly that the amount of oblateness away from perfectly spherical is higher than Everest, and yet you seem to be saying that earth's supposed one revolution a day can affect dense rock over 4 billion years but does nothing to water...[e]ven Mr Tyson used the analogy of pizza dough, if it was wet pizza dough that was being spun are you saying that the water would stay on the pizza as it alone bulges?
That's Doctor Tyson to you, asshole. Your disrespect is not evidence of anything but your personality flaws. As to his pizza dough analogy, it was an analogy.  It was meant to illustrate a point, not be a perfect metaphor for the Earth.

Now, let me ask you: how is water not like rock, soil, and the other components of the surface of the Earth? Oh, yeah it's a fluid! That means that, having been pushed out by the slow centrifugal force, it is not going to stay there. But the land masses can't just quickly fall back into the center. Newton figured this out over 300 years ago, by the way.

His next question is: Can we see the curve or not? I answered, but he ignored me to parrot yet another flat-Earth trope about the curve in one direction being steeper than the other, according to the standard model. Here's how he puts it:
[W]e also have cameras that approximate our field of view and do not suffer from the limitations of rods and cones, and when you draw a line on the horizon of the pictures they take they are always perfectly flat. So you are trying to say that the earth curves quite sharply in one direction and not another, because if you lose the height of a boat in 3 miles, if it goes another mile then you would lose the height of the boat squared, another mile and that resulting height is squared again and so on.
Before I go into the comparison between a side-to-side view of the horizon and something going over it, let me address his claim about cameras. Cameras don't actually approximate our field of view. There is a certain length of lens that is considered "normal," which we perceive as approximating our field of view, but in fact, human vision is far more complex, and while it is limited in some ways, parts of our vision system are remarkably acute.

 Now let's talk about seeing the curve, using his example of "losing the boat in 3 miles." I assume he's using three miles because on the globe, that's the approximate distance to the horizon for someone six feet tall standing right at the water's edge. In reality, the horizon is a little close because your eyes are not right at the top of your head. But let's go with three miles.

His first error is saying that you lose the boat at three miles. That's when the boat's waterline matches the visual horizon. It's only as it goes further out that you begin to lose sight of it.

Then things get weird. He says that when you lose the boat, you lose the boat's height squared in the next mile. And that just makes no sense whatsoever. Here's what would actually happen. At mile three, the waterline of the boat sits on the horizon. At mile four it sits eight inches below the horizon (or, more accurately, below the line of sight between your eyes and the horizon). At mile five, it sits 32 inches below the horizon, then 72 at mile six. If the boat is 15 feet above the water line, it will be visible until it is 7.75 miles away. So no, we don't lose the boat at three miles.

Now, let's try to estimate the degree to which you should be able to see the curve of the horizon. Let's go with a camera for two reasons: first, Murphy did, and second, anyone claiming to see the curve can always be called a liar; a photograph is at least better evidence, even if it, too, can (and often is) dismissed as fake or distorted.

So could you see the curve, undistorted, standing on the short of the ocean with a camera? Let's use one of those "normal" lenses, with a field of view of 45 degrees. On my camera, that would be my 28mm lens. So, with the camera six feet above the water, how much horizon would you actually see? A little trig shows that it would be only about 2.23 miles. Let's say three to give Dave the benefit of the doubt (I'm trying to help you, Dave, but it's not easy).

The bulge in the middle of a three-miles-wide view on a 25,000-mile-circumference planet is (wait for it)...18 inches. At three miles distance, that's an angular size of 0.005 degrees. About 19.5 arcseconds. That's smaller than a single pixel in the field of view. And that's assuming that you are looking at the circle face-on which, of course, you very definitely are not.

The problem, Dave, is that you spout crap about what we should and should not see, but you never really run the numbers. Are you sure about your CV? Because at this level of mathematical ineptness, in the days when I hired software engineers, I never would have hired you.

So, still without any satisfactory rebuttal from Dave, we move on to question three, "Why haven't we seen curved water." My answer was simple: we have. Here's Dave's response:
No we have never observed curved water, you are mistaking the action of perspective and ocean waves as some kind of hump of water, if your eyeline is 5 feet from the ground and 6 miles out to sea there are 6 foot waves, even though those waves have been forshortened to a hard horizon by perspective and so are invisible to you, they are still higher than your eyeline and so will obscure the bottom of the buildings 12 miles away... simple perspective. Regarding Lake Baikal one need not use ladders, targets and scopes, but just look at the perfectly flat reflection that the lake makes of the sky, any curvature whatsoever would produce a distorted image but one always sees a perfect reflection.
This just keeps getting better. First, we are to believe that any object higher than our sight line (which are foreshortened to a hard horizon, however that's supposed to work) will obscure objects beyond it, even if they are higher than the object in front of us. I doubt that Dave would be willing to experiment with that, but a YouTuber called Shnaz Shin schooled another YouTuber named Anthony Riley on that very point. I'll leave it to Dave to go find it.

Then, hilariously, Dave mentions Lake Baikal, where I would be very much astonished to hear of six-foot waves, especially with Dave speaking of perfect reflections in the water. What is more astonishing still is that Dave, ostensibly schooled in science, would choose the sight of the "perfectly flat reflection" over simple measurements. That's just incomprehensibly irresponsible. But then, this is a man who promotes a flat Earth.

So that brings us to question four, where Dave repeats the old saw about the pressurized atmosphere of Earth meeting the "perfect" vacuum of space, which he supposes should not be possible. I accused him of conflating the idea of vacuum, the lack of, well, anything, with the idea of a vacuum cleaner. He took umbrage, but his answer hardly satisfies:
Try not to put words in my mouth sir, vacuum does not pull but a region of high pressure will always move to a region of low or zero pressure, and I note that you did not address my thought experiment, if you evacuate a container to a fraction of the perfect vacuum of space, turn it upside down and puncture the bottom, why doesn't the much stronger gravity at the surface prevent the air from rushing into the much less perfect vacuum?
Note that Dave's thought experiment is just the opposite of the situation with the Earth as a whole. In his experiment, the vessel for the partial vacuum is surrounded by air under pressure (created by gravity); the pressurized air is pushing in from all directions against the vessel and the hole created by puncturing the vessel gives it a chance to equalize the local pressure. Gravity is not going to prevent the air from rushing into the lower-pressure area; it's going to facilitate it.
Regarding the rising column of air, how can a column of air heated by the sun meet less dense air above it? Does the sun only heat air molecules at the surface? or would the air at the top of the atmosphere be the first to be heated and rise and disturb the boundary condition?
Here Dave is making the assumption that whatever is closest to the sun will heat up first. There are so many factors that determine how heat energy gets distributed throughout our dynamic atmosphere (which is as dynamic as it is mostly because the Earth is turning, a sphere, and tilted with respect to our plane of orbit) that cherry-picking any one example is just dishonest. And lazy.

Now we come to one of the flat-Earther's favorite topics: crepuscular rays. Dave thinks that these rays, which only appear in the morning or evening (which is what the word "crepuscular" refers to) point to a close sun. I'll ignore the awful geometry of that assumption for the moment to concentrate on Dave's biggest mistake: he says in the video that the "official" explanation for the diverging rays is that the are refracted by the Earth's atmosphere. Which is wrong. And yet he never corrects himself in this rebuttal:
Crepuscular rays were debunked by the images that I showed on the video...[p]erspective works when viewing objects along ones field of view, like a line of telegraph poles receding away from you, but not across your view, the skyscrapers of the [M]anhattan skyline aren't affected by perspective when you view them from across the river in New Jersey.
Well, that's not actually true about the buildings in Manhattan; the fact that they appear so close together when you see them from far away is entirely due to perspective. So is the fact that crepuscular rays appear to diverge, and Dave has done nothing to rebut that other than claim it isn't true. But if his explanation is true, that the rays are actually diverging from a close sun, then just what is the distance to the sun?

Dave's next question assumes that he is right about the last one: how does a convex lens make light diverge. He is assuming that anyone said that any of these effects are caused by refraction through the "lens" of the Earth's atmosphere, which no one did. But with this question is a picture of an airplane, with its shadow cast on a cloud below. He claims that the shadow is bigger than the plane, but it's not; it's just closer than the plane. But now he comes up with this:
[T]he airplane's shadow is not only magnified but it is also warped as a result of the diverging light rays (or do you think they mount the jet engines pointing outward at a 15 degree angle?)
Do you think that a cloud is flat like a piece of paper? Of course the shadow is distorted! Are you this thick, or are you just being incredibly dishonest?

Dave's next question is about artificial horizons. Flat-Earthers seem to think that these are merely gyroscopes, but they are not. I answered this question in the original post, and here is his response:
Actually most commercial jets have the good old mechanical Artificial horizon as a backup in case their electronics go down... I mentioned that gyros have the property of rigidity in space, but I didn't mention the other perculiar property, precession, that is when a force is applied to the gyroscope to correct its orientation the result of the force appears 90 degrees away from it, thus making it impossible to correct some imaginary "mechanical gravity compensator".
Impossible to "correct some imaginary 'mechanical gravity compensator'"? I don't know about you, but I am less inclined to believe someone like Dave on this matter, and more inclined to believe the people who actually design the avionics that keep airline flight the safest mode of transportation there is.

Dave's next question involves the Coriolis Effect. First he starts with:
Gosh you are so knowledgeable about so many things, why is that?
 It's because I know how to do research with reliable sources, unlike you.
Please show me the calculation for determining the effect of coriolis on bullets or artillery shells from a particular latitude and longditude, shooting toward a particular latitude and longditude.And while you are at it, please show me a pilot who will state that they make constant course corrections because of the coriolis effect or have ever had to take it into account for any reason... I'll wait...
 The calculation you're looking for is here. And why would I show you a pilot that does that when I already said in my previous response that there are many other forces at play, and that the pilot just works at staying on course without regard to which force he or she is compensating for.

Coming into the home stretch. The next question comes down to "on ISS footage, why don't things closer to the ISS move fast, as they do on this footage I'm showing of a landing airplane." My answer was that they do, but that the effect is minimized since the ISS is not close to the ground. This is his rebuttal:
The ISS is supposedly 250 miles from the surface, however the field of view spans thousands of miles, if the photographs taken from the ISS are anything to go by, more than enough to observe a parallax effect that is nowhere in evidence on that blue and white thing pretending to be the earth.
A look at the footage he supplied shows that an easily-identifiable cloud feature moved eight pixels from one frame to the next when at the top of the globe, and 57 pixels from one frame to the next near the bottom. Case closed, Dave, you're just wrong.

Dave's next question is "How can microgravity be selective?" He claims that ISS footage shows a water drop, and a ketchup bottle sitting on the table unaffected by gravity. My answer: it was not a drop of water, and the ketchup bottle had Velcro on the bottom. His response:
From my days producing animations, I know how difficult it is to realistically simulate something dropping to the floor. It was undoubtedly a drip which accelerated toward the ground as it would do on earth.
I looked more closely at the footage. I think what I see is a transmission artifact, to be honest. There is no source for the little blip of white, nor does it seem to land on anything. And it's hard to believe that Dave can derive its acceleration (which, wait, if he accepts gravitational acceleration, then he has to accept at least the effect of gravity, which means that a flat Earth is impossible) from the few frames during which the aberration is visible.
The ketchup bottle had nothing on its bottom, there was only a light reflection that moved as the bottle tumbled in the air, and when struck, it did not move as if it were velcro'd to the table.
No, there was a patch of Velcro, which moved out of the line of sight as the bottle tumbled in the air. I invite any thinking person to look at the footage to see what happened when the bottle got bumped. It wobbled, with the base still in place. It didn't scoot, it didn't tip. It wobbled, it was anchored, and this whole line of inquiry is preposterous.

The next question (next to the last, I promise!) asks why there are craters on the moon, specifically, why are there craters on the side that faces the Earth? In other words, wouldn't the Earth get in the way? His diagram was, of course, way out of scale, making it look like the Earth was an impenetrable barrier to the incoming meteors. He admits that, but still continues with the same assertions:
It's true what you say about the scale, it was for illustrative purposes only, however, the earth has apparently 6 times the gravity, so any large body aiming to hit the one side of the moon that we see will always have its path affected by the earth's gravity... so why don't we see any elliptical craters?In order to produce the circular craters that we see, the incoming body must strike the moon perpendicular to its tangent, which would be impossible in the presence of a large gravitating body like the Earth.
He's asserting that circular craters could only be created by incoming bodies perpendicular to the surface, for which he has no proof. But more than that, he destroys his own question when he mentions the Earth's gravity affecting the incoming meteors. Because that gravitational tug could quite easily pull a body toward the moon that would not otherwise have hit it. Oops.

The last question is a lovely finale to a really mind-numbing ride: why are there no permanent hills, valleys, and mountains in the ocean? He didn't like my answer, thinking that I missed his point. But his efforts to correct me are kind of hilarious:
Why did you avoid the point of my question? Of course water finds its own LEVEL, but it nonetheless deforms under a constant force, swirl water around and it will dip in the middle as long as the force is applied, place a stack of powerful neodynium magnets underwater close to the surface and the water will deform as long as the force is applied. The Mariana Trench is 7 miles deep, that is 7 miles closer to the centre of the earth thus the force of gravity should be much stronger at that point, a CONSTANT force that should deform the water significantly and if that is the case then water around your globe should be deformed into peaks and troughs proportionably according to the seabed's distance from the centre of the earth.
But of course, the water is not a uniformly deep layer of water. The Mariana Trench is seven miles deep, but it also has seven miles of water sitting on top of it, denser at the bottom than near the top. If the water above the trench were lower than the surrounding water, then the other water (being a fluid and not, say, a sheet of plastic) would flow in to fill the gap.

As far as gravity being much stronger at sea level minus seven miles than at sea level, I suggest that might be another situation in which running the numbers might be helpful. Hint: F=G(m1*m2/r^2) is your friend.

Dave Murphy closes with this:
It is apparent from your elementary attempt to answer these simple questions with erroneous suppositions and desperate contrivances that perhaps it does take an astrophysicist to answer them, and not some anonymous bod on the internet who thinks he is one.
He really thinks this cuts deep, and that is perhaps the most astounding aspect of this whole flat-Earth affair. These people really think they are smarter than the rest of us. They really think they have something here the rest of us don't have. They really think, in short, that they have what it takes to change the world. Instead of what they really have, which is just a lot of nonsense to peddle.

Monday, July 10, 2017

Shooting the Moon

Last night I went out and took a picture of the full moon. I do not have a telescope with a camera adaptor, nor do I have an extremely long lens. But with nothing but the 55-200mm zoom that came with my Nixon D3300 DSLR, I was able to come up with a pretty good estimate for the angular size of the moon.

The shot is not very sharp, because although the sensor is 24 megapixels, I used autofocus (I was pressed for time) and shot handheld. Here is the original (scaled for the blog):

Obviously, not very close, but good enough to get a pretty good reading on the pixel width, which turned out to be 435 pixels. Here's the image cropped:

Now, according to this calculator, using the lens at 200mm, the angle of view is six degrees, forty-three minutes, thirty seconds, and each pixel represents 4.043 seconds. So 435 pixels times 4.043 seconds is about 1759 seconds, or about 29 and a half minutes of arc.

According to another online calculator at, the moon's angular size was 29 minutes, 49 seconds, so my estimate from this simple picture was only about 1/180th of a degree off.

What is the purpose of this exercise? Foremost, it is to show that these measurements given by astronomers are not "received wisdom" that we just accept without challenge. Everyone has access to at least some way to verify that they are true. And this is true of most measurements involving Earth, the moon, and the sun.

A secondary purpose is to get anyone tempted by the flat-Earth idea to do a little mathematical thinking. It can be shown mathematically that an object with an angular size of about 29.75 minutes is about 115 times its width away from the observer. You can even test this experimentally by taking a picture of, say, a basketball from 30 yards away.

Now, if a bunch of people all over the world do the exercise to measure the angular size of the moon at the same time, and they all get similar results, this presents a big problem for the flat-Earth notion. Because if I take the above picture at 9:30 in New England, and someone else takes a picture in, say, England at 2:30 in the morning, and we both get the same result, then the moon must be very far away.

Otherwise, one of us would be seeing a much smaller moon. It's just the mathematics of the situation. Again, this is something that can be modeled to scale to verify the theory.

If the moon is very far away, then it must be quite large, certainly more than the 32 miles or whatever that flat-Earthers claim. And if it's big and far away from a flat plane, then how can it possibly be ten degrees above horizontal, as it was when I photographed it last night?

Flat-Earthers will be tempted to invoke some kind of refraction, similar to Rob Skiba's version of atmospheric lensing. But before you go down that road, you should spend a little more time with lenses. Because if a lens magnifies something, it doesn't do it selectively. A lens isn't going to make the moon look bigger as it gets further away without also making seem higher off the ground at the same time.

The next temptation might be to say: "Well, the moon isn't a real object; it's a self-illuminating projection of some sort." I can tell you several reasons why that can't be true, but there's no need. Because even a self-illuminating projection can't defy the simple truth of angular size.

In short, there is no way that any model of a flat Earth can match what we see in reality. It just doesn't add up (or divide or multiply, for that matter).

If you are going to go around people to "trust their senses," then you should be prepared to follow through with some kind of proposition that actually matches what our senses tell us.

Or better yet, trust your senses. They will tell you that the Earth is, indeed, a globe.