Planet position error in GREEN MARS (spoiler)
goatl...@gmail.com
Second Martian Revolution in 12 October 2127, when Mars heliocentric
longitude (Ls) is supposedly 101 degrees. The timing on that day is
triggered by two facts: Earth's west Antartic ice sheet breaks off and
begins to melt in the Pacific Ocean and Mars and Earth will supposedly
be on opposite sides of the sun then.
The melting Antartic ice is valid speculation about the future of
natural history. But the error in the orbital placements of Mars and
Earth are not.
The REAL truth is that, on 12 October 2127...
Earth's heliocentric longitude is: 19.63 degrees
Mars' heliocentric longitude is: 333.13 degrees (NOT 101 DEGREES).
The next time Earth and Mars will be on opposite sides of the sun is
16 July 2128.
The previous time it will have happened is 25 June 2126.
Argh!
Oh well. Heinlein goofed up, too, with the trajectory of the
spaceship "Rolling Stone" on the trip from Mars to "The Hallelujah
Node" and he invented a "Venus departure date" from Mars that didn't
really exist. (He was bang-on right with his celestial mechanics with
the Earth-to-Mars transit, though.)
David Sims
goatl...@gmail.com
wrote:
> Near the end of the GREEN MARS, Nadia and Sax agree to begin the
> Second Martian Revolution in 12 October 2127, when Mars heliocentric
> longitude (Ls) is supposedly 101 degrees. The timing on that day is
> triggered by two facts: Earth's west Antartic ice sheet breaks off and
> begins to melt in the Pacific Ocean and Mars and Earth will supposedly
> be on opposite sides of the sun then.
>
> The melting Antartic ice is valid speculation about the future of
> natural history. But the error in the orbital placements of Mars and
> Earth are not.
>
> The REAL truth is that, on 12 October 2127...
> Earth's heliocentric longitude is: 19.63 degrees
> Mars' heliocentric longitude is: 333.13 degrees (NOT 101 DEGREES).
> The next time Earth and Mars will be on opposite sides of the sun is
> 16 July 2128.
> The previous time it will have happened is 25 June 2126.
>
Come to think of it, Earth's heliocentric longitude is about 19 or 20
degrees on EVERY 12th of October, meaning that if Mars really had been
at 101 degrees heliocentric longitude, it would NOT be about to go
behind the sun, as seen from Earth. Instead, this would have happened
about six months previously and would not happen again for another 20
months.
goatl...@gmail.com
wrote:
>
> - Show quoted text -
Ah, nevermind that previous comment. I was using heliocentric
ecliptic longitude with the zero in the direction of Earth's Vernal
Equinox. Mars' Vernal Equinox is 85 degrees ahead (counterclockwise)
from Earth's. That means that when Mars' position in Martian ecliptic
coordinates is Ls=110 on a 12 October by Earth's calendar, Mars and
Earth would be on approximately opposite sides of the sun. However,
Mars ISN'T at Ls 110 on 12 October 2127. Nope! Uh uh.
goatl...@gmail.com
>
> - Show quoted text -
On 12 October 2127, as seen from Earth, the Sun will be in the
constellation Virgo, while Mars will be moving from Saggitarius to
Capricornus. Lots of room there for the evil UNTA on Mars to yelp for
help from Earth.