[Maryjasmine]

http://www.abc.net.au/radionational/...clic3f/4111996

The link above is to a recent Ockham's Razor talk on Radio National. I was immediately suspicious because the speaker has spoken previously on the same show, in which he promoted ideas of alignments of outer planets in the Solar System causing earthquakes. Anyway, he seemed to be on theme again in this latest talk, suggesting that alignments of Saturn, Jupiter and the Earth are responsible for regular global cataclysms. (Personally I'm quite unhappy that topics like this get approved for Ockham's Razor - are they that short of speakers?)

Anyway, I have two questions out of the talk.

1. How frequently would alignments of Saturn, Jupiter and the Earth take place? Or, to put it more generally, given the orbital periods of three objects, how do you calculate the frequency with which they're aligned? For some reason I just can't visualise how the maths works. (The speaker suggests an interval of 1000 years and I can't tell whether that's suspiciously large, suspiciously small or suspiciously accurate.)

2. The speaker talks about an eclipse being recorded as occuring over Babylon in 136BC when our information suggests it should have been seen over Spain at that time. Does anyone know anything about this anomaly?

[Buyingtime]

1. How frequently would alignments of Saturn, Jupiter and the Earth take place?

Saturn and Earth, a bit less than once a year. Jupiter and Earth, a bit less often than that. Saturn and Jupiter, a bit less often than once a Jupiter year. All three, well technically it never happens but you mean within certain parameters. Within certain parameters it happens almost every time Jupiter and Saturn line up, so every 15 to 20 years or so.

Someone else will have a better answer.

[blackjackiisre]

As mwf suggests, for a three body 'alignment' you need to specify how tight you want the alignment to be (and also whether they all need to be on the same side of the Sun or just in a 'straight line' but on opposite sides of the Sun). For suffficiently tight alignments the frequency will be essentially never and for suffficiently loose alignments they will be very frequent.

There was no solar eclipse over either Spain or Mesopotamia in 136BCE: http://eclipse.gsfc.nasa.gov/SEatlas...atlas-0139.gif

[Alliopeti]

There was no solar eclipse over either Spain or Mesopotamia in 136BCE: http://eclipse.gsfc.nasa.gov/SEatlas...atlas-0139.gif

Well Wikipedia List of Solar Eclipses in the 2nd Century BC has one at 15th April 136BCE which looks pretty close. And the map you linked to has one at -0135 April 15 which is close enough if NASA includes a year 0.

I thought the conventional explanation for the discrepancies in the actual versus predicted locations of ancient eclipses was changing periods of orbit and rotation.

I listened to the talk and in my barely considered opinion it is nonsense.

Reminds me of John Gribben's meretricious book "The Jupiter Effect". I believed it to be rubbish at the time and it was rubbish. I have refused to read anything by him because I decided not to trust anything he wrote after that.

[voksveta]

// There was no solar eclipse over either Spain or Mesopotamia in 136BCE

Pftf, if 'u want to 'no' more about celestial bodies lining up, try NASA's JSEX.

http://eclipse.gsfc.nasa.gov/JSEX/JSEX-index.html