newhorizons

Moon diameter
« on: August 03, 2019, 03:56:09 PM »
FW Wiki quotes in several places that the Moon has a diameter of just 32 miles.  How do you figure that out given that just one of the craters on the Moon has a diameter of nearly 60 miles?  Several independent sources quote a figure of nearly 60 miles as listed below.

https://en.wikipedia.org/wiki/Copernicus_(lunar_crater)

http://www.daviddarling.info/encyclopedia/C/Copernicus_crater.html

https://www.quora.com/Is-Copernicus-the-largest-crater-on-Moon

https://www.skyandtelescope.com/observing/how-to-see-lunar-craters-with-the-naked-eye102820152810/



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Offline Tom Bishop

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Re: Moon diameter
« Reply #1 on: August 03, 2019, 04:21:58 PM »
Some of those numbers are "classic" holdovers from the pre-internet society. I agree that it shouldn't be stated without reference to how it was determined.

The Cosmos page was recently changed from it's previous state by another author. I prefer the original list of links which just gives out information which is known. If we are going to give out a description with figures it should ideally be disclaimed how it was determined and on what axioms.

Lady Blount had an interesting way of determining the size of the Sun which did not involve angular diameter and an assumption of distance. She references experiments in which the angle of the photons from the sun was perfectly vertical over a distance span of 32 miles on earth simultaneously. However, that information seems to be a 404 when I went to look for it recently.

In any event, the way the information is presented in the Wiki should be adjusted to either not describing it, describing it in a more general nature, or showing how if the earth is flat these must be the conslusions about the celestial bodies based on angles or angular diameter.
« Last Edit: August 03, 2019, 04:32:00 PM by Tom Bishop »

newhorizons

Re: Moon diameter
« Reply #2 on: August 03, 2019, 05:30:57 PM »
Appreciate your reply Tom with regards to the Moon. FE Wiki is a primary source of information and reference for the FES so I would have thought that it would be in the best interests of the Society to ensure that the information it carries is as accurate as possible. Anyone visiting for the first time for example and reading claims about the Sun and Moon only being 32 miles across or 3000 miles away are going to quickly head for the exit door and not bother returning.

Concerning what you say about this Lady Blount, I cannot find any specific dates concerning her life time but late 19th/early 20th century would seem to cover it. I would be interested to know more about these experiments with solar photons you make reference to.  Considering the modern concept of photons was only just being developed by the early 20th century.  To establish that photons from the Sun were only perfectly vertical over a distance of 32 miles is pretty good going. How exactly did she come to that conclusion?   

As for the 404 error... well that means of course that the webpage has been removed and there are a number of reasons for that which come to mind.
« Last Edit: August 03, 2019, 05:34:55 PM by newhorizons »

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Offline Tom Bishop

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Re: Moon diameter
« Reply #3 on: August 04, 2019, 07:15:20 AM »
I'll take another look for her experiments. It was in one of her "Earth's Observatory" articles.

Until the society (or societies) can come to an agreement on the dimensions and distance of the Sun and Moon under the current FE model, which is different to what Voliva and Blount held, I recommend that the descriptions on the Cosmos page be changed to something like the following:

"The Sun is a sphere which revolves above the Earth on a path known as the ecliptic. Its path moves North-South over the year between the Tropic of Capricorn to the Tropic of Cancer. Its daily cycle is one revolution per 24 hours."

"The Moon is a sphere which revolves above the surface of the Earth in a manner similar to the Sun. It moves at a slightly slower rate of revolution, at about 347.81° per 24 hours, rising and setting 50 minutes later each day. The Moon has a monthly phase cycle, ranging from Full Moon to New Moon."

"The planets are spheres which move above the face of the Earth and across the sky with apparent relationship to the Sun. Known to antequity as 'wandering stars', the planets were once thought to be key to the nature of the Solar System and the Earth's place in it."

"The stars are luminous elements which move in a layer above the Sun and Moon at a rate of about one rotation every 23.93 hours. The stars range in observable sizes approaching one tenth the diameter of the moon, come in various colors--green, purple, blue, orange--as well as various types, such as rapidly flashing pulars."

The planets and stars pages can be written to match the descriptions. Information on Ptolmy and Copernicus's epicycles and views for the planets page with an FE interpretation--the system of the planets is not necessarily the system of the earth. Galleries of the types of stars will help to show that the stars aren't really generic suns like our Sun as commonly thought.
« Last Edit: August 05, 2019, 05:44:59 AM by Tom Bishop »

newhorizons

Re: Moon diameter
« Reply #4 on: August 04, 2019, 12:26:56 PM »
Quote
The stars are luminous elements which move in a layer above the Sun and Moon at a rate of about one rotation every 23.93 hours. The stars range in observable sizes approaching one tenth the diameter of the moon, come in various colors--green, purple, blue, orange--as well as various types, such as rapidly flashing pulars."

I would agree that the stars range in size, and I would take the description of 'one tenth of the diameter of the Moon (~350km) to mean the highly compact neutron stars.  Mind you even that is being a bit generous as neutron stars can collapse down to just 20km or so diameter. At the other extreme red super giants like Betelgeuse for example have a radius comparable to that of the orbit or Mars. Since stars like the sun (a dwarf star) are all many times larger than the Earth, we can measure their luminosity and the temperature from the light we receive from them. A simple equation then allows us to determine their radius.

We can also tell using a variety of tested methods that the stars also vary tremendously in distance. The brightest star in the night sky by apparent magntitude is Sirius which we see as magntitude -1.42. This is bright only because of its proximity to us of just over 8 light years. By contrast a 1st magntiude star in Cygnus is around 3500 light years away. That translates into an absolute magnitude of -8. So if it was located at a standard distance of 10pc away we would see it easily in broad daylight. The current (IAU quoted) mean distance to the Sun from Earth is 149,597,870,700 metres. That is not a number you come to by approximation. It has been measured. It is a simple matter from there to measure the true diameter of the Sun by using its apparent size on the sky.

The colours of the stars you mention are in part due to the refractive properties of the atmosphere.  This is evident by the coloured twinkle of the stars being far more apparent in stars visible at low altitude and especially when the air is unsteady.

« Last Edit: August 04, 2019, 12:52:54 PM by newhorizons »

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Offline Tom Bishop

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Re: Moon diameter
« Reply #5 on: August 04, 2019, 02:32:09 PM »
On the size of some stars being one tenth the size of the Moon, I guess it can be reworded better that it is in reference to the visible apparent diameter of some stars being one tenth the visible disk of the Moon.

See this story which describes that some of the visible stars are truly huge:

http://m.nautil.us/issue/60/searches/the-popular-creation-story-of-astronomy-is-wrong

" Astronomers dating all the way back to Ptolemy during the second century had determined that the more prominent of those star dots measure somewhere in the range of one-tenth to one-twentieth the diameter that the round moon appears to be. In On the New Star, Kepler said bright stars measure one-tenth the moon’s diameter, Sirius a bit more. "

Under a model with distant stars it would need to be of tremendous proportions, and was one of the early controversies in astronomy. The geocentric model's closer stars seemed more reasonable. Some Copernicans claimed the mystery of God and later ones postulated an optical illusion.

Also see this interesting Scientific American article about the history of Heliocentrism vs. Geocentrism starting on p.75:

https://web.archive.org/web/20160530221846/http://www.hep.fsu.edu/~wahl/artic/SA/mag/2014/201401.pdf

"Copernicus’s revolutionary theory that Earth travels around the sun upended more than a millennium’s worth of scientific and religious wisdom. Most scientists refused to accept this theory for many decades—even after Galileo made his epochal observations with his telescope. Their objections were not only theological. Observational evidence supported a competing cosmology—the “geoheliocentrism” of Tycho Brahe. Copernicus famously said that Earth revolves around the sun. But opposition to this revolutionary idea didn’t come just from the religious authorities. Evidence favored a different cosmology."

Heliocentrism won in the end, of course, but arguably on basis of illusions and other philosophy. Some of the stars are still considered to be large, despite that, although not as large as what angular diameter would suggest, and it is taught today to be entirely reasonable. The articles are worth a read.
« Last Edit: August 04, 2019, 03:52:35 PM by Tom Bishop »

newhorizons

Re: Moon diameter
« Reply #6 on: August 04, 2019, 03:54:34 PM »
Quote
On the size of some stars being one tenth the size of the Moon, I guess it can be reworded better that it is in reference to the visible apparent diameter of some stars being one tenth the visible disk of the Moon.

I don't know which stars that sort of statement might refer to Tom, but with the exception of the Sun, we cannot see the physical disks of any other stars without resorting to specialist techniques possible only at the worlds largest observatories. For example I believe the VLT can be used to detect the physical disk of Betelgeuse with all of the main 8.2m telescopes working in unison as an interferometer.

The Sun itself of course has a visible disk equal in size to that of the Moon.  So which stars have a size one tenth that of the Moon? I have been studying astronomy for a looonnngg time and I have never come across that suggestion.  Modern astronomers both amateur and professional would laugh at such a claim.

The universe has been tranparent to light (all types of EMR in fact) since about 300,000 years after the Big Bang. That is the moment when the Universe cooled down enough to allow neutral atoms to form. Before that the elementary particles that formed during the primordial nucleosynthsis period created a kind of fog which interacted with photons making their mean free path about centimeter or less.  After neutral atoms formed at the epoch of Recombination the Universe became transparent to light and so photons could traverse the Universe unhindered.

So now light can travel for unlimited distances across the Universe. Quasars can be seen across billions of light years across space and I have personally imaged galaxies using my home observatory equipment which are almost a billion light years away.  The size of stars is irrelevant. It is the amount of energy (light) they are emitting that decides how far across space they can be seen from. You may be aware of the so-called 'holes' in the milky way which are actually clouds of cold, dark hydrogen (part of the ISM). The molecular hydrogen making these clouds have larger diameters than the wavelength of optical light and so the light from stars behind these clouds is absorbed. The astronomer E.E Barnard catalogued many of them which is why the Horsehead Nebula for example is listed as Barnard 33.

I agree some stars are considered to be large. Extremely large. We can determine that from studies of the light they are emitting.  As I stated before we can easily measure luminosities and temperature using both spectral analysis and by comparing their brightness at two distinct wavelengths (colour index). So we don't need to see their physical disk size to know they are big.

I don't understand why flat Earth theorist don't seem to acknowledge the progress of astronomy made since about the middle of the 19th century. I agree that more progress has been made in astrophysics and cosmology during the last century to 150 years than ever before. There have been some ideas and hypotheses that have led us to dead ends but others have brought us new and exciting knowledge. That is the same with everything in life. It seems to be only the former that FE people seem to acknowledge. Less than 25 years ago we had not discovered any planets beyond our own solar system. Now thanks to the Kepler spaceprobe we know they are common place. It is surely only a matter of time before we discover another 'Earth'; a planet supporting life (but not necessarily humanoid of course).  I'm not so excited about that prospect though I have to say. I will continue to love studying the Universe whether there is life elsewhere in it or not.
« Last Edit: August 04, 2019, 07:05:37 PM by newhorizons »