Mercury was a grave matter of concern for astronomers in the last century, with its seemingly erratic behavior. Since the precession of its perihelion was in conflict with Newtonian predictions (thus threatening the long-established and vigorously-defended heliocentric model), Einstein pulled out of his hat some fancy equations that, basically, told us that we cannot trust our eyes.
As it turns out, Mercury’s behavior is not so erratic at all. Yes, its orbital plane is slightly inclined (as viewed from Earth) in relation to the Sun’s orbital plane, which causes its elevation vis-à-vis the Sun to oscillate quite a bit, yet it simply revolves around the Sun in lunar fashion. It rotates around its axis 2X faster than Venus and 3X slower than our Moon — and orbits the Sun once in 116.88 days (on average) — which is precisely 4X the time needed for our Moon to orbit once around Earth (29.22 days).
Now, these would all be rather odd “coincidences” under the Copernican model under which the orbital paths of Mercury and Earth’s Moon are entirely separate and independent of each other. Conversely, Mercury and our Moon’s many uncanny common traits would appear to make far more sense within the TYCHOS model, wherein Mercury revolves around the Sun, which in turn revolves around the Moon and Earth. We will see further on (in chapter 29) that our Moon and Mercury are, indeed, very much “intimately related”.
Is Mercury tidally or magnetically locked to the Sun in some way, just as our Moon is tidally locked to Earth? Until around the year 1965, every astronomer in the world would have told you that, yes, Mercury is “tidally locked” with the Sun (meaning that it always shows the same face to the Sun). That was the year that official NASA and Russian Space Agency sources announced with great fanfare that, according to their modern radar data, Mercury was not, after all, tidally locked with the Sun. This caused an uproar in the astronomy community and the question is still debated to this day. As I will now demonstrate, however, Mercury is most likely tidally locked with the Sun (and so is its “big sister” Venus, which I’ve expounded further on) much like our Moon is tidally locked with Earth.
Mercury’s Short and Long ESI (Empiric Sidereal Interval)
Every 7 years, an Earthly observer will see Mercury realign six times with any given star at ca. 358-day intervals. However, the 7th time, it will “run late” by about 50 days and only line up again with the star in 408 days.
Why does this take place?
You guessed it. Just like Mars, Mercury also has two Empiric Sidereal Intervals: a “Short ESI” and a “Long ESI”.
In 14 years, Mercury completes 12 Short ESIs (of ca. 358 days) and two Long ESI (about 50 days longer). Below is a charted sample of a 14-year Mercury cycle (from July 6, 1998 to July 5, 2012) which I compiled with the NEAVE online Planetarium.
I chose – for a reason that should become clear – to start counting Mercury’s yearly revolutions at a given moment in time (just as it entered a Long ESI) as it transited in front of a given star which I used as reference. My celestial reference point was the star “Asellus Australis” in the Cancer constellation.
I found that Mercury lined up with my reference star on the following dates:
|LONG:||July 6, 1998 Start||→||Aug 19, 1999||=||409|
|SHORT:||Aug 19, 1999||→||Aug 11, 2000||=||358|
|SHORT:||Aug 11, 2000||→||Aug 3, 2001||=||357|
|SHORT:||Aug 3, 2001||→||July 25, 2002||=||356|
|SHORT:||July 25, 2002||→||July 17, 2003||=||357|
|SHORT:||July 17, 2003||→||July 9, 2004||=||358|
|SHORT:||July 9, 2004||→||July 4, 2005||=||360|
|LONG:||July 4, 2005||→||Aug 16, 2006||=||408|
|SHORT:||Aug 16, 2006||→||Aug 8, 2007||=||357|
|SHORT:||Aug 8, 2007||→||July 30, 2008||=||357|
|SHORT:||July 30, 2008||→||July 22, 2009||=||357|
|SHORT:||July 22, 2009||→||July 14, 2010||=||357|
|SHORT:||July 14, 2010||→||July 7, 2011||=||358|
|SHORT:||July 7, 2011||→||July 5, 2012 End||=||364|
TOTAL : 5113 days
Average sidereal period of Mercury:
5113 / 14 ≈ 365.22
As you can see, we have a pattern which repeats every 7 years – yielding a mean figure of Mercury’s sidereal period amounting to 365.22 days. In other words, if you know when and where to start computing Mercury’s celestial motions, you will find that Mercury is very much locked with the Sun’s yearly orbit around Earth. This is because Mercury is a moon of the Sun.
It is truly perplexing that, as far as I know, no one has noticed to this day the fact that Mercury’s sidereal periods can be averaged out (in spite of their irregularity) to nigh precisely 1 solar year. To be sure, this would constitute a most astounding “coincidental happenstance” under the Copernican model (wherein Earth and Mercury supposedly revolve at different speeds around the Sun).
You may now be asking yourself, “Why does the TYCHOS model contend that Mercury’s mean synodic period amounts to 116.88 days rather than 115.88 days as most astronomy tables show?”
Here is a series of 14 intervals I have personally verified for Mercury’s synodic periods, over a 1636-day time span.
Note: a synodic period is the time interval between two successive conjunctions of any given celestial body with the Sun.
14 successive Mercury Synodic Periods
Source: NEAVE Planetarium
|Oct 24, 2003||→||March 3, 2004||=||131 days|
|March 3, 2004||→||June 18, 2004||=||107 days|
|June 18, 2004||→||Oct 5, 2004||=||109 days|
|Oct 5, 2004||→||Feb 14, 2005||=||132 days|
|Feb 14, 2005||→||June 3, 2005||=||109 days|
|June 3, 2005||→||Sept 17, 2005||=||106 days|
|Sept 17, 2005||→||Jan 26, 2006||=||131 days|
|Jan 26, 2006||→||May 19, 2006||=||113 days|
|May 19, 2006||→||Aug 31, 2006||=||104 days|
|Aug 31, 2006||→||Jan 7, 2007||=||129 days|
|Jan 7, 2007||→||May 3, 2007||=||116 days|
|May 3, 2007||→||Aug 15, 2007||=||104 days|
|Aug 15, 2007||→||Dec 18, 2007||=||125 days|
|Dec 18, 2007||→||April 16, 2008||=||120 days|
1636 / 14 ≈ 116.857 days
Hence, my 116.88-day value for Mercury’s true mean synodic period appears to be virtually on the mark.