Re: Curiously 8,000 years is less than 10,000 years
About the only thing that is clear is that nine is the wrong number if we intend to find that the Sumerians had special knowledge of the solar system. No way to justify nine. If we include the moon we ought to include at least Titan, Ganymede, Callisto, and Io. In fact there are 100s of moons in the solar system. But then the Sumerians did not use the number nine. So djufo is wrong, but more detail is needed to evaluate Sumerian knowledge. I'm sure there is plenty o 'Chariot of the Gods' style BS to be found on the subject.
The solar system bodies that could have been seen without a telescope by ancient astronomers were the Sun, the Moon, and the planets Mercury, Venus, Mars, Jupiter, Saturn, and Uranus. Neptune is magnitude 7.8, and beyond the range of even the sharpest human eyesight. Pluto is smaller than the Moon, and should never have been classified as a planet; it is 14th magnitude at best, and needs a fair-sized telescope to see at all. I have never seen Pluto, not even with a 14" telescope, so the Sumerians could not possibly have known about it.
There is good evidence that at least one of the satellites of Jupiter (probably Ganymede, or two satellites close together) has been seen with the naked eye. All four Galilean satellites are brighter than 6th magnitude, and in principle they could be seen without a telescope, but the brightness of Jupiter itself puts them out.
Titan (Saturn's largest satellite) is magnitude 8.4, and cannot be seen without a telescope. The asteroid Vesta is sometimes visible with the naked eye; however, I have never heard of Ceres being seen without binoculars or a telescope.
Adding this up, we reach a possible total of ten bodies, the seven planets from Mercury to Uranus, the Moon, Ganymede, and Vesta. Of course, we must not forget comets, which can be spectacular although temporary visitors to the night sky.