[adrian_b]

In that Wikipedia article, "prehistorically" is improperly used.

"Prehistoric" means before the appearance of written records, which means before the 3rd millenium BC (when there are many Egyptian and Sumerian/Akkadian written records).

There is no evidence that the planets (i.e. excluding the Sun, Earth and Moon) were known prehistorically.

The evidence is actually that 4 planets, Mercury, Mars, Jupiter and Saturn, have been discovered, as correctly written in the Wikipedia article, only in the 2nd millennium BC, in Babylonia. That is a historical time not prehistorical.

The only planet known in prehistory was Venus, because it is much brighter than any star, so its movement on the sky is obvious, but it was known as 2 distinct stars, the Morning Star and the Evening Star.

Only very late it became understood that there is actually a unique celestial body that appears in 2 forms.

This discovery was made in Sumer, probably in the 3rd millenium BC, or maybe as early as the 4th millenium BC. (This Sumerian discovery is reflected in the legend of Inanna, who descends in the underworld, then she returns to the heavens, like the Evening Star disappears and then returns as the Morning Star).

This knowledge has propagated to other places only very slowly.

For example Homer mentions some stars and constellations and also both the Morning Star and the Evening Star, but there is not the slightest hint that he or the other Greeks of the 8th century BC might have known that those 2 "stars" are in fact the same body.

[sdenton4]

Yeah, the use of 'prehistory' seems not great in this context; there's a fundamental problem of how we would know which bodies were known prior to the existence of a writing system.

But there are a number of things that make these very discoverable: They are visible with the naked eye, all lie in the ecliptic plane, and behave a bit strangely if you watch them over time. Mars is a bit red, and absolutely stands out... And of course Venus can't be ignored. Once you've noticed Venus and Mars, finding the others is a matter of looking a bit harder.

Using stars for navigation or for measuring the passage of time involves observing them consistently, which leads one to notice 'odd' things. So I wouldn't at all be surprised if the planets were known in, say, prehistoric Polynesian cultures... The appearance of mathematical astronomy in Babylonia tells us that the movement of celestial bodies is approximately the first scientific knowledge a civilization will bother to write down.

https://en.wikipedia.org/wiki/Babylonian_astronomy#Old_Babyl...

[thaumasiotes]

> The appearance of mathematical astronomy in Babylonia tells us that the movement of celestial bodies is approximately the first scientific knowledge a civilization will bother to write down.

In fact, we know (from ruins) that the Chinese were practicing astronomy at a time well before our first written records of them.

It is a certainty that the planets were known to all prehistoric cultures; I don't know what adrian_b is thinking.

[adrian_b]

There exists no evidence whatsoever that any prehistoric culture was aware about the existence of planets.

Of course they would have noticed Jupiter and Mars when they are brighter than the stars, as extra stars in known constellations, but there is no evidence that anyone realized that the extra bright star seen once in a certain constellation is the same with the extra bright star seen next year in another constellation.

Because it was not yet understood that the planet sightings are the same bodies that just move on the sky, they were thought as stars that appear or disappear randomly.

Like I have said, not even Venus, the brightest body on the sky after the Sun and Moon, was recognized as a single star, but it was believed to be 2 different stars until 6000 years ago in Sumer and until as late as 2600 years ago in Europe.

Noticing a bright star on the sky is not the same with knowing its nature.

The next 4 planets after Venus have been discovered in Babylonia because they began to make written continuous records with the positions of the stars during many years.

Only then, after comparing the written records accumulated after many years, it was realized that the planets are not stars that appear and disappear randomly, but they move in continuous trajectories on the sky, with definite speeds and if you know their position at some time you can predict their future position at another time, because they never stray from their path.

So only after the Babylonian discoveries it became understood that the stars are divided in fixed stars, wandering stars a.k.a. planets, which have predictable trajectories, and the comets, which are the only stars that appear and disappear randomly.

[thaumasiotes]

With all due respect, you have no idea what you're talking about, and you're asking us to believe things that cannot possibly be true.

Some cultures remained prehistoric much later than others. Here's some evidence from one of them:

> what information we do have tells us that [Australian] Aboriginal people were close observers of planets and their motions, noting the relative brightness of the planets, their motions along the ecliptic, retrograde motion, the relationship between Venus and its proximity to the Sun, Venus’ connection to the Sun through zodiacal light, and the synodic cycle of Venus, particularly as it transitions from the Evening Star to the Morning Star.

> Indigenous cultures around the world, particularly the many hundreds that exist in Australia, maintain complex astronomical knowledge systems that link the positions and motions of celestial objects and to navigation, calendars, subsistence, and social applications

> The Sun, Moon, and visible planets (Mercury, Venus, Mars, Jupiter, and Saturn) were known to Aboriginal and Torres Strait Islander people. These cultures paid careful attention to the motions of solar system bodies through careful observation, which was recorded and passed to successive generations through oral tradition and material culture. Aboriginal and Islander people distinguished planets from the background stars, noted their changing positions in the sky, their changing positions relative to each other, their proximity to each other along the zodiac of the ecliptic, and their dynamic relationship to the Sun and Moon.

( https://arxiv.org/ftp/arxiv/papers/1806/1806.02462.pdf )

All cultures observe the sky closely, and all of them identify the planets, which are one of the most interesting -- and obvious -- phenomena in the sky.

Show me the Sumerian astronomical records that describe Jupiter as being two different objects.

[adrian_b]

There are no Sumerian astronomical records.

The written astronomical records that are known appeared a few hundred years after the Sumerians no longer existed, in the 2nd millenium BC.

The Sumerian language is sometimes used by the Akkadian scribes in all kinds of documents, including in astronomical records, but it was already a dead language.

Thanks for the linked paper, it is interesting.

It shows that there are cases when the identity of the planets may be discovered using only detailed oral traditions.

However, that is a quite unlikely event and it happened very seldom in other cultures.

Even if the stories of the Australian aborigines have been interpreted correctly, there is no way of knowing if they had already recognized some planets 10 thousand years ago or only 500 years ago, for the first time.

In order to recognize even the more obvious planets, i.e. Mars and Jupiter, based on oral stories, there must be a habit to recall things that happened long ago, during the last few years, while always mentioning that when that happened, the reddish bright star Mars was in a certain constellation or Jupiter was in some another constellation.

When telling such old stories, you can notice that now a similar star, which might be the same, is in another position.

This is possible, but even in prehistoric cultures it was seldom thought interesting to mention which was the exact star pattern on the sky when something happened.

The normal story pattern was to be more vague about such things of low interest and say just that some event took place e.g when a certain constellation became visible soon after sunset, instead of also describing how many stars were visible in the constellation and which were their individual characteristics.

Such special interest in precise star description might have characterized the Australian aborigines and maybe also the Polynesians and other people who depended on astronomical navigation, but it was unusual at most other people.

In any case the identification of the brighter planets based on oral memories is much more likely to happen in a dry climate, where you might notice the planet every night and recognize it even if it has moved slightly and after seeing it during many months you may realize that it actually is no longer in the same place.

In climates with more frequent clouded skies, it is less likely to recognize when you see again a planet that it is the same as that seen some time ago, because by the time when its position has changed enough its brightness might have also changed, so there is no apparent reason to believe that a new star of different position and brightness is the same as the one previously seen, unless you have seen all the intermediate steps of position and brightness.

This might explain why some planets might have been discovered by Australians based on only oral memories, while no such cases have been seen in Europe or Asia.

[sdenton4]

Venus changes its astrological sign (ie, moves 1/12th of its way through the sky) roughly monthly, and Mars changes about every two months; noticing these changes doesn't require a complex multi-generational oral tradition. Jupiter and Saturn are slower, but still complete a full cycle within a person's lifetime.

https://www.elsaelsa.com/astrology/how-long-do-planets-stay-...

Which is to say, these are noticeable differences for individuals, especially any who are using the fully-evolved intelligence of a human brain staring regularly at the sky instead of a smart-phone.

[thaumasiotes]

I don't know how you got into this state, but suffice it to say that most of your comment is quite flagrantly false. It is clearly not worth trying to talk to you.