APOD: The Antikythera Mechanism (2021 Mar 21)

[APOD Robot]

The Antikythera Mechanism

Explanation: No one knew that 2,000 years ago, the technology existed to build such a device. The Antikythera mechanism, pictured, is now widely regarded as the first computer. Found at the bottom of the sea aboard a decaying Greek ship, its complexity prompted decades of study, and even today some of its functions likely remain unknown. X-ray images of the device, however, have confirmed that a main function of its numerous clock-like wheels and gears is to create a portable, hand-cranked, Earth-centered, orrery of the sky, predicting future star and planet locations as well as lunar and solar eclipses. The corroded core of the Antikythera mechanism's largest gear is featured, spanning about 13 centimeters, while the entire mechanism was 33 centimeters high, making it similar in size to a large book. Recently, modern computer modeling of missing components is allowing for the creation of a more complete replica of this surprising ancient machine.

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[profweather]

Not the first computer; only the oldest found. To have something this precisely constructed and complicated tells us there are other devices, lost to time, which preceded this one, possibly by centuries.

[RocketRon]

Amazing machine !
And haven't they found remnants of things that can only have been galvanic batteries (elsewhere).
Who knows, maybe it was battery powered (joke).

The question is - what would the display of this mechanism have looked like ?
A jeweller of all people has one such suggestion...
https://www.heathercoleman.co.uk/upload ... 1_orig.jpg

You only have to see medieval clocks to realise that quite complicated mechanisms have been around
in one form or another for quite a long time ...

[Astronymus]

Amazing machine !
And haven't they found remnants of things that can only have been galvanic batteries (elsewhere).
Who knows, maybe it was battery powered (joke).

The question is - what would the display of this mechanism have looked like ?
A jeweller of all people has one such suggestion...
https://www.heathercoleman.co.uk/upload ... 1_orig.jpg

You only have to see medieval clocks to realise that quite complicated mechanisms have been around
in one form or another for quite a long time ...

Those batteries were probably used for gold plating, not for energy.
Same with ancient steam devices. Just amusing toys.
As long as slaves were cheap enough people had no use using such devices for power or locomotion.

[Just Curious]

In clicking through the links you included with your explanation, I found reference to astronomer Johann Titius' 1766 discovery of a mathematical progression to estimate the orbital radii of the planets in AU's (see below) & noticed that there is reasonably close agreement to the actual mean radii (in a table included in that reference), except that there is no planet corresponding to (4+24)/10. Do you know of any explanation for this?
Mercury (4+0)/10 = 0.4 vs 0.39 AU
Venus (4+3)/10 = 0.7 vs 0.72
Earth (4+2x3)/10 = 1.0 vs 1.0
Mars (4+4x3)/10 =1.6 vs 1.52
? (4+8x3)/10 = 2.8
Jupiter (4+16x3)/10 = 5.2 vs 5.2
Saturn (4+32x3)/10 = 10 vs 9.54
Uranus (4+64x3)/10 = 19.6 vs 19.2

[neufer]

Plot of the eight planets, Pluto, & Ceres versus Bode's predictions

---

• The real problem is Neptune.

I I found reference to astronomer Johann Titius' 1766 discovery of a mathematical progression to estimate the orbital radii of the planets in AU's (see below) & noticed that there is reasonably close agreement to the actual mean radii (in a table included in that reference), except that there is no planet corresponding to (4+24)/10. Do you know of any explanation for this?
Mercury (4+0)/10 = 0.4 vs 0.39 AU
Venus (4+3)/10 = 0.7 vs 0.72
Earth (4+2x3)/10 = 1.0 vs 1.0
Mars (4+4x3)/10 =1.6 vs 1.52
? (4+8x3)/10 = 2.8
Jupiter (4+16x3)/10 = 5.2 vs 5.2
Saturn (4+32x3)/10 = 10 vs 9.54
Uranus (4+64x3)/10 = 19.6 vs 19.2

[Ann]

In clicking through the links you included with your explanation, I found reference to astronomer Johann Titius' 1766 discovery of a mathematical progression to estimate the orbital radii of the planets in AU's (see below) & noticed that there is reasonably close agreement to the actual mean radii (in a table included in that reference), except that there is no planet corresponding to (4+24)/10. Do you know of any explanation for this?
Mercury (4+0)/10 = 0.4 vs 0.39 AU
Venus (4+3)/10 = 0.7 vs 0.72
Earth (4+2x3)/10 = 1.0 vs 1.0
Mars (4+4x3)/10 =1.6 vs 1.52
? (4+8x3)/10 = 2.8
Jupiter (4+16x3)/10 = 5.2 vs 5.2
Saturn (4+32x3)/10 = 10 vs 9.54
Uranus (4+64x3)/10 = 19.6 vs 19.2

Well, you shouldn't really ask me...

However...

Based on the Titus-Bode law that you describe in your post, there should indeed have been a planet between Mars and Jupiter. The asteroid belt has been used to explain why there is no major planet in the proposed location. The hypothetical planet, called Phaeton, was believed to have "exploded" and created the rocky fragments of the asteroid belt. But according to Wikipedia, this hypothesis has now been discarded.

Instead another hypothesis has been put forth, the Grand Tack hypothesis. According to this proposal, Jupiter migrated closer and closer to the Sun in its youth, until it was stopped in its migration when it entered into orbital resonance with Saturn.

According to this hypothesis, Jupiter swept the part of the Solar system that is now the asteroid belt mostly clear of material. That is why the asteroid belt is so sparsely populated, and that is also why Mars is so small. There was not a lot of planetary material for Mars to sweep up after Jupiter had moved back and forth over this part of the Solar system like a giant snowblower.

So what about the Titus-Bode law, then?

Well, what about it? I don't know.

Ann

[orin stepanek]

it's amazing whatt man has built 2000 years ago!


APOD Quote

, and even today some of its functions likely remain unknown.

even kitty was amazed!

[De58te]

re: Just Curious wrote,
I'd have to read up with Bode's law, but I can see by the numbers that there is a pattern. For the inner rocky planets the distance increases between each planet by 1.5 times. The distance between the gaseous planets doubles. There is a jump between Mars and Jupiter where a planet should be at (4+8x3)/10 which would have puzzled Titius since Ceres wasn't discovered yet. There wouldn't be a planet at (4+24)/10 because if you look at the Bode formula, the numbers divided by 10 have been doubling since Earth to Mars. The next planet after Jupiter would have been at (4+32x3)/10 which is Saturn. Of course Neptune ignores the doubling space by returning to the 1.5 space again. (It is 1.5 times farther away from Uranus.) But then Titius wouldn't have known that since Neptune hadn't been discovered in his lifetime. Uranus wasn't discovered either in 1766 when Bode's law was proposed but that might have led to Uranus' discovery some 15 years later. Titius lived to see that.

[Chris Peterson]

In clicking through the links you included with your explanation, I found reference to astronomer Johann Titius' 1766 discovery of a mathematical progression to estimate the orbital radii of the planets in AU's (see below) & noticed that there is reasonably close agreement to the actual mean radii (in a table included in that reference), except that there is no planet corresponding to (4+24)/10. Do you know of any explanation for this?
Mercury (4+0)/10 = 0.4 vs 0.39 AU
Venus (4+3)/10 = 0.7 vs 0.72
Earth (4+2x3)/10 = 1.0 vs 1.0
Mars (4+4x3)/10 =1.6 vs 1.52
? (4+8x3)/10 = 2.8
Jupiter (4+16x3)/10 = 5.2 vs 5.2
Saturn (4+32x3)/10 = 10 vs 9.54
Uranus (4+64x3)/10 = 19.6 vs 19.2

There is a plausible explanation. The nature of planetary system formation from a collapsing stellar disc, combined with the re-arrangment of planets in their orbits early in such a system's formation can easily lead to some type of power-law distance relationship (but the actual exponent could be anything, meaning that the factor of 1.5 seen in our system is mere coincidence). But there is no natural law forcing this, and any number of events or perturbations could break the relationship. Which is evident in simulations, as well as actual observations of other planetary systems.

In other words, what we are probably seeing is a combination of coincidence and tendencies that can be reinforced by orbital resonances.

[E Fish]

Learning about the Antikythera mechanism is what initially pushed me into studying the history of science. It's amazing, in part because it represents a height of engineering that was lost a century or two later. The general impression many people get is that science is always progressing, but there are many moments in history where we can see knowledge being lost, technology being lost and in some cases, lost so thoroughly that even the memory of ever having it is gone.

Another example of lost (and recently rediscovered) knowledge is the Archimedes Palimpsest which was found hidden on the parchment used for a prayer book. It contains two works by Archimedes that were completely lost. http://www.archimedespalimpsest.org/

[Chris Peterson]

Learning about the Antikythera mechanism is what initially pushed me into studying the history of science. It's amazing, in part because it represents a height of engineering that was lost a century or two later. The general impression many people get is that science is always progressing, but there are many moments in history where we can see knowledge being lost, technology being lost and in some cases, lost so thoroughly that even the memory of ever having it is gone.

Another example of lost (and recently rediscovered) knowledge is the Archimedes Palimpsest which was found hidden on the parchment used for a prayer book. It contains two works by Archimedes that were completely lost. http://www.archimedespalimpsest.org/

I think we need to distinguish between lost records, lost engineering, and lost science. The first happens trivially, as with the Archimedes Palimpsest, where very little actual knowledge was lost, just the words of a person. The second is less common, but happens as we see with the Antikythera mechanism. The last is rare. I can think of few examples where actual scientific knowledge (that is, knowledge about how nature operates) was gained and then truly lost, with a need that it be rediscovered.

[neufer]

In other words, what we are probably seeing is a combination of coincidence and tendencies that can be reinforced by orbital resonances.

<<Kepler-90 is a G-type main sequence star. It is notable for possessing a planetary system that has the same number of observed planets as the Solar System.

• The Kepler-90 planetary system:

Code: Select all

Companion 	Semimajor axis(AU)  Orbital period (days)
-----------------------------------------------------------------------------
b 		0.074 ± 0.016 		7.008151
c 		0.089 ± 0.012 		8.719375
i 		0.107 ± 0.03 		14.44912
d 		0.32 ± 0.05 		59.73667
e 		0.42 ± 0.06 		91.93913
f 		0.48 ± 0.09 		124.9144
g 		0.71 ± 0.08 		210.60697
h 		1.01 ± 0.11 		331.60059

Kepler-90's eight known planets all have periods that are close to being in integer ratio relationships with other planets' periods; that is, they are close to being in orbital resonance. The period ratios b:c, c:i and i:d are close to 4:5, 3:5 and 1:4, respectively and d, e, f, g and h are close to a 2:3:4:7:11 period ratio. f, g and h are also close to a 3:5:8 period ratio. Relevant to systems like this and that of Kepler-36, calculations suggest that the presence of an outer gas giant planet (as exemplified by g and h in this system) facilitates the formation of closely packed resonances among inner super-Earths. The semimajor axis of any additional nontransiting outer gas giant must be larger than 30 AU to keep from perturbing the observed planetary system out of the transiting plane.>>

<<TRAPPIST-1 is an ultra-cool red dwarf star. Seven temperate terrestrial planets have been detected orbiting it, more than any other planetary system except Kepler-90. A study released in May 2017 suggests that the stability of the system is not particularly surprising if one considers how the planets migrated to their present orbits through a protoplanetary disk.

The orbital motions of the TRAPPIST-1 planets form a complex chain with three-body Laplace-type resonances linking every member. The relative orbital periods (proceeding outward) approximate whole integer ratios of 24/24, 24/15, 24/9, 24/6, 24/4, 24/3, and 24/2, respectively, or nearest-neighbor period ratios of about 8/5, 5/3, 3/2, 3/2, 4/3, and 3/2. This represents the longest known chain of near-resonant exoplanets, and is thought to have resulted from interactions between the planets as they migrated inward within the residual protoplanetary disk after forming at greater initial distances.>>

[ta152h0]

I can imagine some modern day toy manufacturer making one of these in plastic and calling it Antikythera game where you predict where the mouse is going to fall into the trap! pass the ice cold one

[Chris Peterson]

I can imagine some modern day toy manufacturer making one of these in plastic and calling it Antikythera game where you predict where the mouse is going to fall into the trap! pass the ice cold one

You can already download the files to 3D print your own model. I'm not sure any of these models include the latest details, but if not, they certainly will very soon.

[neufer]

Click to play embedded YouTube video.

I can imagine some modern day toy manufacturer making one of these in plastic and calling it Antikythera game where you predict where the mouse is going to fall into the trap! pass the ice cold one

You can already download the files to 3D print your own model. I'm not sure any of these models include the latest details, but if not, they certainly will very soon.

[Knight of Clear Skies]

If anyone is interested in a book on the Antikythera Mechanism I can recommend 'Decoding the Heavens' by Jo Marchant.

[sillyworm 2]

Are we ABSOLUTELY sure it is not a corroded pedal car steering wheel?

[E Fish]

Learning about the Antikythera mechanism is what initially pushed me into studying the history of science. It's amazing, in part because it represents a height of engineering that was lost a century or two later. The general impression many people get is that science is always progressing, but there are many moments in history where we can see knowledge being lost, technology being lost and in some cases, lost so thoroughly that even the memory of ever having it is gone.

Another example of lost (and recently rediscovered) knowledge is the Archimedes Palimpsest which was found hidden on the parchment used for a prayer book. It contains two works by Archimedes that were completely lost. http://www.archimedespalimpsest.org/

I think we need to distinguish between lost records, lost engineering, and lost science. The first happens trivially, as with the Archimedes Palimpsest, where very little actual knowledge was lost, just the words of a person. The second is less common, but happens as we see with the Antikythera mechanism. The last is rare. I can think of few examples where actual scientific knowledge (that is, knowledge about how nature operates) was gained and then truly lost, with a need that it be rediscovered.

I can agree with that. I, too, can think of few examples. In fact, the only other that immediately comes to mind is Sung Su's water clock.

[RocketRon]

I think we need to distinguish between lost records, lost engineering, and lost science. The first happens trivially, as with the Archimedes Palimpsest, where very little actual knowledge was lost, just the words of a person. The second is less common, but happens as we see with the Antikythera mechanism. The last is rare. I can think of few examples where actual scientific knowledge (that is, knowledge about how nature operates) was gained and then truly lost, with a need that it be rediscovered.

Thats a rather rose tinted glasses view of history ?

I think we need to consider 'the dark ages' in Europe, when the Roman Empire withdrew back and then collapsed.
In Britain and indeed most of Europe, science, engineering, medicine, art and indeed civilisation was most definitely lost or on the back foot.

It was only during the Renaissance of the circa ~15th century that all this knowledge was regained, mainly from Arabic and Indian sources.
Even our numbering and alphabet/symbol set come from these sources.

That was 1000 years of being in the doldrums ???
For Europe anyway ...
Vikings excluded ? - their seafaring and star navigation skills in particular.

[Chris Peterson]

I think we need to distinguish between lost records, lost engineering, and lost science. The first happens trivially, as with the Archimedes Palimpsest, where very little actual knowledge was lost, just the words of a person. The second is less common, but happens as we see with the Antikythera mechanism. The last is rare. I can think of few examples where actual scientific knowledge (that is, knowledge about how nature operates) was gained and then truly lost, with a need that it be rediscovered.

Thats a rather rose tinted glasses view of history ?

I think we need to consider 'the dark ages' in Europe, when the Roman Empire withdrew back and then collapsed.
In Britain and indeed most of Europe, science, engineering, medicine, art and indeed civilisation was most definitely lost or on the back foot.

It was only during the Renaissance of the circa ~15th century that all this knowledge was regained, mainly from Arabic and Indian sources.
Even our numbering and alphabet/symbol set come from these sources.

That was 1000 years of being in the doldrums ???
For Europe anyway ...
Vikings excluded ? - their seafaring and star navigation skills in particular.

No, no tinted glasses. Modern understanding is that the "dark ages" were far less dark than they have been portrayed in the past. Little knowledge was lost, and much was gained, albeit as a somewhat reduced pace compared with various eras of discovery.

[RocketRon]

But if the knowledge largely had to be re-imported/sourced from Arabic and Indian sources,
then that would suggest that the knowledge had been lost in Europe ??

There is also the matter that the massive library in Alexandria had burned and declined
over the centuries - wasn't it said that half the past knowledge of the world had gone ?
History may be a little sketchy on this too, we don't even know what we don't know ...
https://en.wikipedia.org/wiki/Library_of_Alexandria

[Chris Peterson]

But if the knowledge largely had to be re-imported/sourced from Arabic and Indian sources,
then that would suggest that the knowledge had been lost in Europe ??

There is also the matter that the massive library in Alexandria had burned and declined
over the centuries - wasn't it said that half the past knowledge of the world had gone ?
History may be a little sketchy on this too, we don't even know what we don't know ...
https://en.wikipedia.org/wiki/Library_of_Alexandria

What actual scientific knowledge or knowledge about the natural world was lost? Had to be "re-imported"? I can't think of much.

Records were lost. Scientific knowledge? Not really.

[neufer]

But if the knowledge largely had to be re-imported/sourced from Arabic and Indian sources,
then that would suggest that the knowledge had been lost in Europe ??

There is also the matter that the massive library in Alexandria had burned and declined
over the centuries - wasn't it said that half the past knowledge of the world had gone ?
History may be a little sketchy on this too, we don't even know what we don't know ...
https://en.wikipedia.org/wiki/Library_of_Alexandria

What actual scientific knowledge or knowledge about the natural world was lost? Had to be "re-imported"? I can't think of much. Records were lost. Scientific knowledge? Not really.

Scientific American
Volume 258, Number 4, April 1, 1988

Ancient Rope-and-Pulley Computer is
Unearthed in the Jungle of Apraphul.

[RocketRon]

You are jumping the gun, April Fools is tomorrow ...