In your book in chapter 23 you discuss star sizes and distances.
Discussing the angular diameters of astronomical bodies, you write about the Airy disk effect and how modern astronomers consider the apparent angular diameters of stars entirely spurious. You rightly point out that astronomers consider the apparent angular diameters of the Sun, the Moon, and the planets as corresponding to their true physical diameters; but the stars, through the optical diffraction phenomenon known as “Airy’s disk,” appear vastly larger than their true size.
Historian of sciences Christopher Graney in this video here (between 31:30 and 34:30) expounds on the two different size aspects between on one side our close celestial spheres and on the other the distant stars but does not explain the reasoning.
How can the angular diameter of the Sun, a star shining light to us through the atmosphere, be true, while the the angular diameter of the stars be an illusion? How do astronomers explain the apparent inconsistency?
The “answer” to your question is in that video you posted featuring Prof. Christopher Graney, the public relations officer (and astronomy historian / adjunct scholar) of the Vatican Observatory Foundation.
It would appear that Prof. Graney has taken a special interest in this peculiar subject matter (star distances), perhaps inspired by Chapter 23 of my TYCHOS book. In fact, he cited my book at the Vatican Observatory’s website on February 4, 2023 - only a month or so prior to that March 10 presentation you linked to.
Here’s the forum post I made back then:
I would suggest you to read Graney’s full article titled "You Can’t See Atoms, so Why Can You See Stars?" since it represents the best answer to your question that I can think of. Once you have done so, please do share with us any thoughts and comments you might have with regards to Graney’s explanations.
Yes, dear Tof. Here’s an extract from Chapter 23 of my TYCHOS book:
As we apply our 42633 reduction factor (1LY = 1.4834AU), we see that the Earth-Sirius distance - in the TYCHOS model - would be about 12.9AU (8.7 X 1.4834 ≈ 12.9). Officially, the “true” angular diameter of Sirius is reported to be a mere 0.005936″; again, this is an incredibly small value, for it would mean that the “actual” size of the disk of light that we call Sirius - the most prominent star in our skies - would be as many as 323450 X smaller than the Sun (1920 / 0.005936 = 323450)! Now, Sirius is estimated to be 1.7 times larger than the Sun; so let’s try and divide that 323450 figure by our 42633 reduction factor - and then multiply it by 1.7; by doing so, we should obtain the true Sun-Sirius distance (assuming that the TYCHOS 42633 reduction factor is correct - and that the intrinsic luminosities of the Sun and Sirius are identical, for why wouldn’t they?):
323450 / 42633 = 7.5868 X 1.7 = 12.8975 (or just about 12.9!)
In other words, Sirius may well be located at only 12.9 AU - yet still be 1.7 X larger (as of current estimates) than the Sun. In any event, the notion that atmospheric diffraction would only alter (and hugely inflate) the apparent sizes of the stars - yet leave our planets’ apparent sizes unaffected - has to be the most bizarre axiom of heliocentrism. Chapter 23: Are the stars much closer than believed? – Nextra
As you may agree, the notion that Sirius is “only” 12.9 x more distant than the Sun is far easier to accept than the officially-proposed notion that Sirius (by far the brightest and visually largest star in our skies) would actually have a “true” angular diameter 323450 times smaller than the Sun!
I read Graney’s article a few months ago when reading the “distance to stars” thread; upon re-reading, I can’t really get past the basic question of “what is a star?” and “what is light?” Since the sun is reckoned to be a star, it is absurd to think we can only “see the sun’s light,” but not the “sun” itself. I understand that expensive telescopes can “see” the surface of the sun - have they ever been able to photograph the surfaces of other stars?
Professor Graney has published a lot of fascinating work and he is a pleasure to read and listen. I think the debate in the middle seventeenth century between Copernicans and anti-Copernicans, based around the physics of optics, came down precisely to this: are stars disks or dimensionless points of lights?
According to Graney, telescopic observations, in the 17th century, proved the Copernican model was physically impossible.
Professor Graney has been delving and spending countless hours into translating works of 17th century Anti-Copernicans written in obscure scientific latin; he is bringing to light the forgotten, scientific objections to heliocentrism and the dense, rich debates that defined this great cosmological debate of the time.
I have read over the years a great many papers by Christopher Graney with great interest. I remember thinking, initially, that he was an advocate of Tycho Brahe’s Tychonic model - only to discover later on that he worked for the Vatican Observatory which, of course, fully embraces heliocentrism.
I am not sure what to think of the strontium atom image he refers to in his article allegedly reflecting a large circle of visible blue-violet light; it seems to be an ad hoc justification of the Copernican distance to the stars argument: an infinitely small, dimensionless dot can create a disk of light millions of times larger. I have no idea about the purported accuracy of the atom image experiment and if it can function as a valid analogy for the apparent angular diameters of stars.
I noticed the same thing Simon. However, and correct me if I am wrong, I believe that at least one quote you have in your book from him was prior to his going to the Vatican. He was at a very small college I think.
He reads like he’s anti-Copernican initially because he’s coming at it from a Biblical point of view irrespective of what the Vatican embraces and then all of a sudden he’s on their payroll. go figure…
Back to Greg’s point on the Airy question, I started a topic a while back that nobody has commented on yet pertaining to your mention of adaptive optics (AO). After reading up on what that is, is struck me that the Airy hypothesis could be dispensed with permanently. What’s your take?
If I understand your point correctly, you are saying that the modern techniques known as Adaptive Optics (which can nowadays separate apparent single stars into two neatly visible bodies) actually disprove the (in)famous Airy disk theory. To be honest, I’ve never really thought of that - but you may have a most excellent point! For if the Airy disk theory were true (i.e that stars appear to be thousands of times larger in telescopes due to ‘atmospheric diffraction’), how then could a new technique such as Adaptive Optics resolve an apparent single star (covering an area of the telescope’s lens believed to be several thousands of times larger than the star’s ‘true’ angular diameter) into two distinct / separate bodies - only marginally smaller than the area covered by the (spurious) “single” star observed without Adaptive Optics?
I am simply pointing out what science has discovered and employed to solve issues that had plagued existing telescopes for centuries.
It is used in astronomical telescopesand laser communication systems to remove the effects of atmospheric distortion, in microscopy, optical fabricationand in retinal imaging systems to reduce optical aberrations.
I don’t see how people will be able to continue to use the Airy excuse to negate the Tychos model when optics have advanced to this degree holding on to an argument essentially based on three-hundred year old technology. (concave mirrors)
For, is it not now possible, with AO separating an object that appears as one into two, to measure them both independently, by which the very process itself gives true arcsecond sizes to both objects. The Airy coverstory, now contradicts itself, for atmospheric distortion effects are no longer an issue.
I though Graney’s answer was very funny. First off Sirius is generating light supposedly light years away. You cannot resolve an atom with the human eye, but you can resolve the diameter of Sirius. His example is completely spurious.
To quote him
“You can see the light from a bright object, even if you cannot see the object itself.”
Yes but you cannot resolve the atom with the naked eye right? I ordered one of his books recently. It should be interesting.