The one inescapable fact about the Moon
is that it orbits the Earth. It is up there beaming down on us, but
according to everything that science knows, it shouldn't be.
A little later Eudoxus of Cnidus,
who was an astronomer and mathematician, calculated the Saros cycle
of eclipses and thereby could predict when they would appear.
The eclipse in question was total in Syene but only partial in Alexandria which was some 729 kilometers away.
Enlisting the help of like- minded
friends, Hipparchus was able to use the known distance from Syene to
Alexandria, together with the angular difference of the total and
partial eclipse to establish the Moon's true size and distance from
With the arrival of Christianity the
world entered a dark age where scripture rather than science was the
only permitted guide to human existence.
The consciousness of cultural rebirth was itself a characteristic of the Renaissance. Italian scholars and critics of this period proclaimed that their age had progressed beyond the barbarism of the past and had found its inspiration, and its closest parallel, in the civilizations of ancient Greece and Rome.
By the end of the sixteenth
century, a genius from the town of Pisa called Galileo Galilei
became one of the most important scientists of the Renaissance
carrying out experiments into pendulums, falling weights, the
behavior of light and many other subjects that captured his
Galileo wrote in April 1610:
From these reports, and by applying his skills as a mathematician and a craftsman, Galileo began to make a series of telescopes with an optical performance much better than that of the Dutch instrument.
His first telescope was made from available lenses and gave a magnification of about four times, but to improve on this Galileo taught himself to grind and polish his own lenses and by August 1609 he had an instrument with a magnification of around eight or nine.
He quickly realized the commercial and
military value of his super-telescope that he called a perspicillum,
particularly for seafaring purposes. As the winter of 1609 brought
colder, clearer nights Galileo turned his telescope towards the
night sky and began to make a series of truly remarkable
Amongst many other findings Galileo
claimed to have proved that the Milky Way was made up of tiny stars,
to have seen foursm all moons orbiting Jupiter and to have seen
mountains on the Moon.
They simply had to be so because God had created them - and none of the Almighty's creations could be flawed.
Eventually Galileo was put under
perpetual house arrest by the Papacy for his blasphemous claim that
the Sun was at the centre of the solar system. It is therefore quite
possible that he knew m ore about the Moon than he was willing to
admit in public.
Perhaps the most popular of these, at
least for a while, was the suggestion that the Moon was a perfect
mirror. If this was the case there were no markings on the Moon but
rather reflections of surface features on the Earth. It didn't seem
to occur to anyone that as the Moon orbited the Earth the markings
should change, since the land beneath it would not remain constant.
The images, it was suggested, were present in sunlight and were merely being reflected from 'the vapors'. But the most popular theory, probably because it didn't impinge on Christian doctrine, was that there were variations in the density of the Moon and that these created the optical illusions we see as markings on the Moon's surface.
This unlikely explanation was safe,
though it probably did little to convince early scientists, and
certainly would not have impressed Galileo.
It is quite easy to establish one's
position on the planet in a north- south line (latitude) but it was
impossible to know where you were in terms of east-west (longitude).
In the northern hemisphere, for example, latitude can be quickly
gauged by measuring the angular distance between the horizon and the
Pole Star. This angle also defines one's position north of the
It wasn't difficult to work out the difference between local time, say at midday, and the time at the home port. It was then simply a matter of adding or subtracting to discover one's true position on the Earth's surface. This was fine but it took many decades before a suitably accurate clock could be created.
In the meantime, astronomers sought for
other methods to determine longitude, not least of all because there
was a fabulous prize on offer for anyone who could crack the
problem. And the place where m any of them turned to establish
longitude was the Moon.
The reason this could work was that the
Moon, being very close to the Earth and orbiting quickly, moved
across the heavens by around thirteen degrees of arc per day. Using
the Moon it was a fairly simple matter to establish 'local time' and
then to do the necessary computations to discover one's position.
George Darwin, the son of Charles Darwin, the controversial Englishman who first proposed the theory of natural selection, was a known and respected astronomer who studied the Moon extensively and came up with what became known as the 'fission theory' in 1878. George Darwin may have been the first astronomer to ascertain that the Moon was moving away from the Earth.
Working backwards from his knowledge of
the rate the Moon was receding from the Earth, Darwin proposed a
time that the Earth and the Moon could have been part of the same
common mass. He suggested that this molten, viscous sphere had been
rotating extremely rapidly in about five and a half hours.
At the time this seemed very reasonable and was the favored theory by the beginning of the twentieth century.
In fact the fission theory did not com e
under serious attack until the 1920s when a British astronomer
called Harold Jeffries was able to show that the viscosity of the
Earth in its semi-molten state would have dampened the motions
required to generate the right sort of vibration necessary to
fulfill Darwin's fission.
There are several reasons why this
theory can't be the answer. Not least is the problem of the angular
momentum of the Earth-Moon system that could never have been as it
is, if the Moon had formed in this way. There are also difficulties
regarding the melting of the magma ocean of the infant Moon.
There are also insurmountable problem s
in trying to build a model that would allow a body as big as the
Moon to take up orbit around the Earth. Such a huge object could not
simply drift neatly into an Earth orbit at low speed like carefully
docking a super-tanker - it would almost certainly smash into the
Earth at a massive speed or possibly skim off and hurtle onward.
As acclaimed science writer William K. Hartmann, senior scientist at the Planetary Science Institute, Tucson, Arizona said in 1986 in his book Origin of the Moon:
Out of this miasma came a new theory
and, in fact, the only one that is presently widely accepted despite
some fundamental problems. It is known as the 'Big Whack theory'.
Hartmann and Davis hypothesized that the
two planets had collided in a very specific way that allowed jets of
matter to be ejected from the mantles of both bodies. This matter
was thrown into orbit, where it eventually came together to form the
It was obvious that the Moon could not contain m any of the heavy elements that are found inside the Earth and the Big Whack theory purported to explain why this was the case.
The Earth and the rogue visitor had come
together in a very specific way. Although they would eventually form
one planet it was reasoned that they must have impacted, drawn apart
and then come together again. Computer modeling showed that under
these very special circumstances it would have been possible for the
material thrown off to have been mantle material, from close to the
surface of the two bodies.
In 1983 an international conference was held at Kona, Hawaii, to try and solve the problems regarding the origins of the Moon.
It was at this meeting that the Big
Whack theory, also known as the Giant Impact Hypothesis of the
Collision Ejection theory, began to gain ground. Hartmann's own
suggestions, together with those of other scientists at the
conference, formed the nucleus of the 1986 book, Origin of the Moon,
which was edited by Hartmann himself.
Canup wrote her PhD dissertation on the
Moon's origin and specifically the Big Whack theory. Her early work
led to the conclusion that the suggested impact would have actually
led to a swarm of moonlets, rather than the Moon, but by 1997
further computer modeling resulted in a model of the impact that
would lead to the Moon's presence.
Canup agrees and the only way that she could deal with this anomaly is to propose a second major impact - which was designated 'Big Whack II'.
This suggests that the second planetary
collision happened perhaps only a few thousand years after the first
one but, quite incredibly, this incoming object came from the
opposite direction and so cancelled out the huge spin imparted to
the Earth by the first cataclysmic event. This balanced double act
sounds unlikely in the extreme. Two cosmic collisions that just
happen to precisely return the planet to its natural rhythm ? To us,
this explanation smacks of desperation!
It has been observed that the oxygen isotope signatures of Moon rocks are identical with those of rocks from the Earth - and that fact has some serious implications:
This would mean that the Mars-sized body
that hit the Earth must have occupied a similar orbit to that of the
Earth and yet had already managed to survive for many millions of
years before it hit the Earth.
The present obliquity of the Earth (its twenty-three degree tilt against the plane of its orbit around the Sun) is usually deemed to be the result of the giant impact, but any body of the size of Mars that was in an orbit similar to that of the Earth could not have had sufficient momentum to knock the Earth's angle of rotation back so severely.
Either the rogue planet was Mars-sized,
and came from way out in the solar system and was therefore
travelling extremely fast, or else it had to be at least three times
the size of Mars, which doesn't tie in with the computer models as
Lissauer is said to have joked to his students about a remark made by another scientist, Irwin Shapiro from the Harvard- Smithsonian Center for Astrophysics:
Lissauer's article pointed out some of the problem s with the Big Whack theory. He made it clear that in his opinion the latest research demonstrated that much of the material blown out by the impact (the ejecta) would have fallen back to the Earth.
Lissauer made it clear that as a result,
he too is of the opinion that the rogue planet must have been
substantially larger than that originally proposed but noted that it
is difficult to see how the excess angular momentum resulting from
such a large impact could have been lost.
After a detailed examination they concluded:
These words used in the conclusion to this biochemical analysis indicate just how hopelessly contrived the whole Big Whack theory is.
They go on to say:
In other words scientists hang onto the
Big Whack theory, even though it has more holes than a rusty
colander, simply because no other logical explanation has been
found. It is just the least impossible explanation for a celestial
body that has no right to be there.
The Moon could, by pure chance, end up
being exactly 1/400th the size of the Sun and occupying an orbit
that allows it to stand 1/400th the distance between the Earth and
the Sun - but the odds are, quite literally, astronomically against
The Apollo 17
Insignia, the last manned
It has been observed that the oldest of the rocks collected from the Moon are significantly more ancient that any rock ever found on Earth.
The most venerable rocks to be found on the Earth date back 3.5 billion years, whilst some samples from the Moon are around 4.5 billion years old - which is very close to the estimated age of our solar system.
When radioactive dating
techniques are applied to meteorites they are uniformly found to be
4.6 billion years old.
We were stunned by what we discovered. The Moon is bigger than it should be, apparently older than it should be and much lighter in mass than it should be. It occupies an unlikely orbit and is so extraordinary that all existing explanations for its presence are fraught with difficulties and none of them could be considered remotely watertight.
We came to realize that many reputable
experts across the world have significant misgivings about current
theories concerning the Moon's origins that, as we have shown in
this chapter, they were quite willing to voice publicly.
The Moon remains, to borrow the words of Winston Churchill,