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### Topics - robinofloxley

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##### Flat Earth Theory / Latitude and longitude - please enlighten me
« on: June 01, 2020, 10:03:35 AM »
I've read a number of posts where latitude and longitude are dismissed by FErs because they are based on a globe earth.

I'd like to unpick this and ask what the actual objections are.

Fundamentally (if you live in the northern hemisphere), your latitude is easily determined. It's simply the altitude of Polaris from your location. It's not an absolute value in miles, km or light years, because to determine that you'd need to know how far away Polaris is and in times past, that wasn't possible to determine. What we do instead is measure the angle from the horizon to the star, because that's easily done and doesn't require you to know any distances.

Longitude is based on time. When was the sun due south at your location compared to when it was due south in Greenwich UK? If that's +1 hour and the sun moves at 15 degrees per hour, then your longitude is 15W.

Both of these are determined easily from the positions and movements of celestial bodies and can be measured with simple instruments (if you consider an accurate timepiece to be a simple instrument).

Neither of these values rely on any preconceived assumption about the shape of the earth.

There is an issue of course if you want to calculate the distance between two points given by latitude/longitude, because that involves spherical geometry and includes an assumption about the shape of the earth.

So is that it? Are latitude/longitude OK by themselves, but the distances are not? What are the actual objections?

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##### Flat Earth Theory / Aristotle's most famous proof for the rotundity of the Earth
« on: May 09, 2020, 08:04:04 AM »
A couple of weeks ago I saw this post from Tom:

Aristotle's most famous proof for the rotundity of the Earth is the Lunar Eclipse. He said that only a round Earth could cause a round shadow. Since the shadow is round, the earth must also be round. However, he was incorrect, and apparently did not experiment much with that idea. Due to the shape of the Moon, a flat sided shadow can also cause a round shadow to appear:

The image is taken from https://wiki.tfes.org/Lunar_Eclipse_due_to_Electromagnetic_Acceleration

I was surprised that such an apparently simple experiment could so utterly demolish Aristotle's argument, so decided to have a go at repeating it myself. I couldn't find a very suitable spot at home, so decided to model it instead. Here's what I came up with:

However, in modelling this, I discovered something quite interesting. If you take a close look at all the shadows (not just the moving shadow), you'll notice that whilst the observer is more or less directly in front of the alcove, the light source (a torch) is coming from somewhere off to the left and above. That's the only explanation for these shadows. And since "the Earth" (a rectangular folder in this experiment) is blocking the light source, then it too must be off to the left and above. I worked out that looking back from the moon, the angular separation between the Earth and the observer needs to be approximately 22 degrees.

In RE terms, that means the observer is located in space approximately 90 thousand miles from the Earth.

So not very realistic then.

I then moved my observation point to where the folder is to simulate an Earth bound observer. This is what I see now.

So not such a devastating demolition of Aristotle at all, just a very misleading image in the Wiki.

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##### Flat Earth Community / Has the flat earth movement flatlined?
« on: May 22, 2019, 11:54:55 AM »
Like many, I came across the flat earth movement a while back and the idea that anyone would believe in such an idea seemed ridiculous. However I was intrigued, came on here and watched various videos. I quickly realised that I had been guilty of sloppy thinking in some areas - for example, I had just assumed that I could see the curve from a commercial airliner at 35k feet. No, you can't, realise that now. I learned a lot of really interesting stuff as a by-product of what I read and watched. I know a lot more about maps and map projections then I ever did. I now know that the zero longitude line is actually 100 metres away from the marking strip at Greenwich I stood astride for my pointless selfie a couple of years back - and I know why. I watched the 2017 eclipse (unforgettable, magical experience), watched the shadow move from West to East - and I now know why that happened too. All thanks to questions raised here and elsewhere.

There have been many great questions and great answers too, but to me it's all going a bit stale now. Same old re-hashed questions over and over again, haven't seen a new or interesting one in ages. On the YouTube side, there are some thoroughly excellent FE debunkers out there who (to my satisfaction) have utterly debunked pretty much every FE argument. Trouble is they now seem to have run out of new and interesting stuff to debunk and it's all a bit flat there too. Now it seems FE is debunking itself, examples are Bob Knodel and the farcical ring laser gyroscope experiment and Jeranism's "interesting" experiment. And now we have Eric Dubay attacking pretty much everybody else.

So has the whole thing simply run out of steam now?

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##### Flat Earth Investigations / Antipodal journeys
« on: November 01, 2018, 03:14:31 PM »
One of the problems with flat earth discussions is that there is no consensus behind any particular flat map, however the one thing I assume everyone does agree on is that whatever it looks like, it will be flat.

On any flat surface, there can only be one shortest route between any two points - a straight line - and therefore only ever one sensible direction of travel if you want to get to your destination via the shortest route.

On a sphere, the shortest route between two points is a great circle arc and in general there is only one great circle passing through both points and hence one shortest route. The exception occurs when the two points are antipodal (directly opposite each other). In this case many great circle routes are possible so there is no longer a single shortest route, there are many.

So for example, on a globe earth, the UK and New Zealand are almost antipodal, therefore you can head off in any direction you like from the UK, follow a great circle route for about 12500 miles and you will be more or less in New Zealand. On a globe travelling in opposite directions yet ending up in the same place makes perfect sense, on a flat earth it doesn't.

In reality, from the UK, I can fly west via Los Angeles to New Zealand or I can fly east via Tokyo and there are plenty of other routes to choose from such as via Hong Kong, Dubai, Manilla etc. These routes all have similar flight durations and cost similar amounts of money.

Anyone care to try and explain?

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