EPSILON BOÖTIS REVISITED.
by Duncan Lunan (Analog, 1998; revised August 2013).
In January 1974 Analog published my article 'Space Probe from Epsilon Boötis?'1, which caused such a stir that I'm still asked about it every time I appear in the magazine. It was based on the mystery of long-delayed radio 'echoes' (LDEs), first reported in the 1920s.
Actually, the 'echoes' were much too powerful to be simple reflections of signals from Earth. Experimenters studying round-the-world propagation of radio waves found their outgoing pulses were being returned to them with a delay of three seconds, as if they were being amplified and returned by something at the distance of the Moon - but definitely not the Moon itself. In later experiments the delay times began to vary upwards from three seconds, in increasingly complicated sequences, but with no variation in intensity - still indicating a single source amplifying and returning the pulses.
Prof. Ron Bracewell of Stanford suggested in 1960 that the 'echoes' might have been rebroadcast by an unmanned probe from another civilisation, trying to attract our attention, and in 1972 I worked out a 'translation' of the 1920's echo patterns. The variations of delay times appeared random; but Prof. Bracewell himself had suggested the first signal from such a probe might be a star map, and the stars are spaced at random in the sky. I tried plotting the delay times against the order in which the echoes were received (fig. 1(A)), and at only the second attempt I found what looked like a star map - in which it appeared that the probe had come from the double star Epsilon Boötis, in the constellation Boötes, the Herdsman (fig. 1(B)). Arcturus, the brightest star in the constellation, seemed to be out of place in the map; but on checking, was shown at its place about 13,000 years ago.
Other parts of the supposed message seemed to give the scale of their planetary system, orbiting Epsilon Boötis A, and seemed at first to make sense. Epsilon Boötis A is an orange giant star, and the translation indicated that the probe makers had evolved on its second planet, emigrating later to the sixth when their sun began to expand. But there was a problem: the companion star (Epsilon B) was bright blue, apparently a short-lived sun of spectral type A2. It emerged that the distance given for the star in most reference books was too low, and at the true distance of 203 light-years, Epsilon B really was an A2 star and the orange giant Epsilon A had been an AO, like Sirius - too massive and with too high a radiation output to sustain habitable planets, too short-lived for life to have evolved there. At the same time, more accurate 1920s records were located, and most of the 'star map' translations were ruled out - not the 'Epsilon Boötis' one, but it too had to be treated as suspect. I withdrew the entire translation,2 but now it seems I may have gone too far.
Dropping it didn't rule out the space probe suggested by Prof. Bracewell (though he himself has abandoned the idea).3 James Strong suggested that the probe could be located in either the 'Lagrange 4' or 'L5' point, also called 'Trojan' or 'Equilateral' points, equidistant from the Earth and Moon.4 The dates and times of the 1920s LDEs showed that the L5 point was at least one source of the effect.5 Anthony Lawton of the British Interplanetary Society suggested that in ideal conditions the Trojan points could form temporary, stable ionospheres of their own which would generate LDE's;6 it was reported that I accepted that, but scientists I consulted replied that such clouds would be disrupted by currents in the Earth's magnetosphere, or at other times of the month by the Solar Wind, the constant outflow of charged particles from the Sun. In any case, as the Lagrange points have no gravitational fields of their own, a cloud of charged particles would be scattered by their mutual electrostatic repulsion - unless there was a powerful magnetic or electrostatic field to hold them in place. If this was produced by a spacecraft, I suggested, Lawton might have hit upon the method by which the Bracewell probe generated LDE's - by accident!
Many books and articles said that Lawton conducted an active radio search for LDEs, but in reality he stopped after getting an initial 'reply', on the grounds that further transmissions "would constitute a biassed experiment". Optical searches of the Lagrange points failed to find anything as large as the Skylab space station, or, in a later search, as large as the Pioneer 10 space probe.7 Meanwhile, however, Epsilon Boötis just would not lie down.
There are several real or suggested Zodiacal star maps, laid out on the ground, which centre on Boötes. That's just because the constellation lies near the pole of the Ecliptic, perpendicular to the Earth's orbital plane around the sun, so any Zodiacal map will be centred near it. But also, we are in Boötes as viewed from Tau Ceti, one of the nearest stars like our Sun, and at relativistic speeds, Epsilon Boötis would be a prime navigational reference on the journey here.8 And there was an even stranger development.
After my book "Man and the Stars" came out,9 I was contacted by Alan Evans, who was then a Captain in British Military Intelligence. He liked the analysis I'd made of Erich von Daniken's claims, where I concluded that Earth had not been visited more than four times, at most. Alan suggested we jointly attempt something still more systematic: if the Earth had ever been visited, our aim would be to find proof. He stressed that his was purely a personal interest, which had to remain confidential, but as he's since left the Army that no longer applies.
We tightened up my approach into four categories of possible evidence. Category A would be our objective, an artefact of unquestionably extraterrestrial origin. Category B would be optical or electromagnetic anomalies pinpointing such an object (like the Tycho monolith in 2001); Category D would be the 'von Daniken material' of legends, drawings etc. which were no use except in suggesting areas to search for other types of evidence. But Alan pressed me to include a new category, C, which would be anomalous astronomical alignments in man-made structures - anomalous because they revealed knowledge which the builders should not have had. For example, on high-resolution photographs of Stonehenge, he had identified markings which seemed to indicate galactic alignments.
I wasn't impressed at first. I had studied megalithic astronomy under a leading expert, Prof. Archie Roy, and seen nothing unusual; there was no correlation even with Category D; and when I did the calculations, the markings Alan had found didn't seem to be galactic. At the time when he put this to me, circa 1975, it was supposed that Stonehenge I was built in 1800 BC, near the end of the Stone Age in Britain (not many people realise that Stonehenge was one of the last megaliths), with Stonehenge III, the inner circle, still later in the Bronze Age. Soon afterwards, however, Archie Roy himself published an article from which we learned that the radiocarbon dating scale had been revised, pushing Stonehenge I back from 1800 BC to 2700 BC. Further revision made it c.2840 BC, and that radically changed the whole position.
Archaeoastronomy at Stonehenge.
Fig. 2A shows the celestial sphere as viewed by an observer in the northern hemisphere. The altitude of the pole above the northern horizon is equal to the observer's latitude, and the heavenly bodies circle around it, parallel to the equator, with the daily rotation of the Earth. The altitude of a body above the horizon, and its azimuth measured along the horizon from the north point, change constantly as the Earth turns. Apart from the circumpolar stars, which are too near the pole to rise and set, everything else rises in the east and sets in the west at a position which is determined by the declination of the object, measured from the equator (Fig. 2B). Where the declination equals the observer's latitude, the star passes overhead once a day.
Horizon positional astronomy was all the Stonehenge builders could do (Fig. 3). Stonehenge I incorporated the ditch, bank, Avenue, Heelstone and Station Stones; what most people think of as 'Stonehenge' are the great sarsen archways of the inner circle, Stonehenge III, erected in the early Bronze Age. It's universally agreed that the Stonehenge Avenue and the later structure both mark the midsummer sunrise. But few archaeologists agree with Gerald S. Hawkins that the 'Station Stones' of Stonehenge I mark the extreme positions of the Moon's 18.6 year cycle;10 and still fewer with Prof. Alexander Thom, that the megalith builders had a sophisticated programme of lunar observatories, spread over the British Isles.11 Personally, I'm convinced; I've even built a modern megalith, under the auspices of Glasgow Parks Dept., to compare its performance with the prehistoric sites, and demonstrated that high precision could have been achieved by naked-eye observations.12
When it comes to star alignments, the position is more complex. Because the Earth's equatorial plane doesn't coincide with the Ecliptic, nor with the orbit of the Moon, the combined pulls of the Sun and Moon on Earth's equatorial bulge cause the Earth's axis to 'wobble' around the Ecliptic Pole with a period of 26,000 years (Fig. 4). 13,000 years ago the north pole star was Vega in Lyra, and 5,000 years ago it was Thuban in Draco, at the time of Stonehenge I. The pull makes the equator move around the Ecliptic, constantly changing the position of the Vernal and Autumnal Equinoxes (Precession of the Equinoxes). As a result a star's declination is constantly changing - likewise its Right Ascension, which is measured from the Vernal Equinox along the equator, in the same direction as the Sun's motion on the Ecliptic shown by the arrows in Fig. 2(B).
Astronomers can partly get round the problem of coordinate change by giving star positions in Ecliptic Latitude, which remains constant, and Ecliptic Longitude, which changes smoothly with time. But for coordinates which are fixed over human time-spans, even the spans of civilisations, we have to use Galactic Latitude and Longitude, whose zero point is the Galactic Centre and whose pole lies on the perpendicular to the plane of the Milky Way (Fig. 5).
On the high-resolution photographs of Stonehenge Alan Evans pointed out a curious horseshoe-shaped marking on the northwest, cutting the bank and overlying Station Stone 93 (Fig. 3). It's not on official plans and may not be significant: the photos were taken in 1966, eight years after one of the fallen trilithon archways was re-erected, and the 'horseshoe' coincides at least in part with the tracks of the heavy machinery used then. We have located a smaller version of it in a prewar aerial photo, but it's still historically suspect. Still earlier photos, taken by balloon, show a similar but different pattern.10 But the relationship the horseshoe pointed out to us was real enough.
As Fig. 3 shows, the orientation of the horseshoe is to the rising point of the Galactic Centre, and of the Galactic Equator's intersection with the Ecliptic, c.2840 BC. Even more extraordinarily, it turns out that the declination of the North Galactic Pole was then equal to the latitude of Stonehenge. Consequently, when the Galactic Centre was on the horizon, the Galactic Pole was in the zenith and the Galactic Equator coincided with the horizon (Fig. 6).
It would be remarkable if that was a coincidence, but if it's not coincidence, it's an extraordinary finding. The Galactic Centre is 27,000 light-years from us and hidden behind dense clouds of absorbing dust in the inner regions of the Milky Way, so its location cannot be pinpointed visually, only with a radiotelescope. Until you know exactly where the Centre is, you can't determine the true plane of the Galactic Equator and the true positions of the Galactic Poles. At the Moscow General Assembly of the International Astronomical Union in 1958, new values for the positions of the poles and the Centre were officially adopted, based on the distribution of neutral hydrogen in the inner Milky Way and study of the radio source Sagittarius A. Previous optical studies had suggested the Centre was in Scorpius, so it was a big change. Maps using the old galactic coordinates were still on sale as late as 1963, with addenda giving corrections to the new system.13 Yet apparently the builders of Stonehenge knew exactly where the Galactic Centre was, or took their cue from something or somebody or who did.
In this context, why are galactic coordinates so important? Imagine a spacecraft travelling between the stars. Its attitude sensing platform might be oriented to its home world - its own Right Ascension and declination - or its home planetary system, its own Ecliptic coordinates. But neither will be relevant when it enters our Solar System: the only coordinate system common to its system and ours is the galactic one. In any manoeuvres or landings it made here, you would expect it to navigate in galactic coordinates; and if it chose a landing site on the declination of the galactic pole, then once a day the azimuth and altitude of any star, measured from the rising point of the Galactic Centre, would correspond to its galactic coordinates, like B's in Fig.6. If the spacecraft's attitude-sensing platform was fixed, built into its structure, it would still be correctly lined up with the sky once a day.
So if the horseshoe marking is modern, its 'prehistoric' alignment might be a curious coincidence. What looks more likely, on Fig. 3, is that there was something in the centre of Stonehenge I, which was gone by the building of Stonehenge II and III. In fact, after Stonehenge I was built, around 2700 BC the site was abandoned for over 200 years while the same neolithic people built the much larger complex of Avebury and Silbury Hill, due north of Stonehenge itself.14
What would annoy archaeologists, who don't even admit most 'conventional' archaeoastronomy, is the suggestion that the Stonehenge orientation is galactic at all. I looked for an optical marker, something which would have let the builders create Stonehenge without knowing about galactic coordinates or even without a spacecraft necessarily being there. And I found one, but it didn't exactly make the alignments less controversial. The star which had the same declination as the North Galactic Pole in 2840 BC, equal to the latitude of Stonehenge, was Epsilon Boötis itself.
It was so hard to believe, when I'd abandoned the Epsilon Boötis 'translation' of the radio patterns, that I arranged to see for myself, twice in the planetarium of the Jewel & Esk College in Musselburgh, then all over again at the much larger one in Armagh. It feels extraordinary to see such findings, worked out with long pages of calculations, simulated on the planetarium 'sky' overhead. With the date set for 2840 BC, at the Stonehenge latitude, the Milky Way really does line up with the horizon once a day and Epsilon Boötis really does go through the zenith as well, earlier each day.
The Ecliptic and the Pyramids.
But Alan Evans has a strong intuitive grasp of spatial relationships, and he had found another which he wanted me to verify. Projected north, the alignment of Station Stones 94-91, and 93-92, meets the Arctic Circle at a tangent (Fig. 7). As the Earth turns, when the Ecliptic Pole comes overhead at that tangential point, those stones mark the Ecliptic Meridian passing through Stonehenge. And when that line is projected south, it meets the equator due south of the Egyptian 'Memphite Necropolis', containing the great pyramids of Giza. Putting it another way, the Ecliptic meridian through Stonehenge meets the prime meridian of Giza at the equator. And Alan realised this created another extraordinary relationship: at midsummer sunrise at Stonehenge, the one alignment there which even the sceptics recognise, the Vernal Equinox was on the prime meridian at Giza.
That one can't be verified optically in a planetarium with the same certainty, because the tilt of the Earth's axis to the equator is not constant, varying between 22 and 24 degrees.15 In 2840 BC it was near maximum, and has since declined by over half a degree. None of the planetaria we've used could allow for that, but the relationship is extremely close, even today. I had my calculations confirmed by Paul Benson, then curator of Airdrie Observatory; and more recently Alan had it all done from scratch by Peter Tyler, (of the Positional Services Dept. of GECO-PRAKLA, Oslo, a leading international seismic survey company), who confirmed that around 2700 BC the alignment was close. In his calculations the margin of error was less than one-fifth of a degree; my own put it even closer.
The oldest features of all at Stonehenge lie over the brow of the hill, northwest from the circle. The 'Car Park Post Holes' held huge vertical tree trunks or totem poles, and radiocarbon dating has them as old as 8000 BC.16 Even that was a mystery: it was believed that the first mesolithic settlers reached Britain long after the Ice Age, around 6000 BC,17 but now we know that people returned to Britain as soon as the glaciers retreated. It's possible that the weathering on the Bluestones of Stonehenge II, which were brought from the Prescelly Mountains in Wales, makes them older and perhaps once erected elsewhere; that could have been any time after they were first exposed to the atmosphere around 12,000 BC.18 The ice sheets never covered Stonehenge and Prescelly, even at their greatest extent in 20,000 BC.15
As Alan Evans pointed out, the Ecliptic Meridian passes through the line of Post Holes,19 on the line of stones 92-93 (fig. 3). If there really was a spacecraft, and its attitude sensing platform was relating our ecliptic and celestial co-ordinates to the galactic ones, then if galactic alignments determined the latitude of the touchdown site on Salisbury Plain, then the ecliptic ones show an intention to go to Egypt afterwards, which determined the longitude and brought it down at the future site of Stonehenge I - which raises the interesting speculation, were the Posts still standing at that time, as if to mark the landing place? Below, we'll see some reason to think that might have been their intended purpose, at least.
The next question is, are any of the Stonehenge galactic alignments repeated at the Old Kingdom Egyptian pyramids? The Step Pyramid at Saqqara, whose longitude is one-tenth of a degree east of Giza's, was the first stone building in the world, created around 2650 BC by the architect Imhotep for the pharaoh Djoser (Fig. 9). Imhotep changed the design several times during construction, and some archaeologists suggest that he filled in the steps with rubble and faced them with limestone, to give the illusion of a true pyramid.27 (The next two, intended to be true pyramids, were partial failures before the Great Pyramid's builders got it right.)
And if the Step Pyramid was originally faced in that way, then as nearly as we can measure it, a perpendicular line up the north face met the prime meridian at the declination of the southern intercept between the galactic equator and the ecliptic, marked I2 in Fig. 3 - one of the same alignments we'd found at Stonehenge. But, extraordinary as all this was, we were still a long way from our goal; we knew what we wanted to do next, but it was beyond our financial means. So we withheld publication, until April 1996, when a whole new situation developed.
The Pyramids and the Sphinx.
Archaeoastronomers are in some ways remarkably conservative. Their own ideas about science in ancient society are rejected by many astronomers and most archaeologists; in consequence, they refuse to entertain any more controversial notions, such as a previously unknown civilisation on Earth, or extraterrestrial visitors. I suggested to the 1996 Edinburgh International Science Festival that we organise a seminar on 'Heresies in Archaeoastronomy', examining the ideas that were too controversial even for archaeoastronomers to consider. Prof. Archie Roy gallantly agreed to introduce it, and not surprisingly it drew a capacity audience. Naturally, Alan Evans was there to present his paper on the Ecliptic meridian.20
Another participant was Robert Bauval, whose book "The Orion Mystery"21 suggested that the three giant pyramids of Giza not only incorporated star alignments in their so-called 'air-shafts' (Fig. 8), but represented the stars of Orion's Belt mapped on to the landscape. When Alan Evans checked their findings, he found that the same shaft which marked the meridian transit of Alnitak, the left-hand star of Orion’s Belt, also marked the transit of the Galactic Centre. So of the two galactic alignments marked at Stonehenge, one was incorporated into the Step Pyramid and the other into the Great one.
Robert had now collaborated with Graham Hancock on a new book, "Keeper of Genesis", based on the possibly great age of the Sphinx. The apparent evidence of water erosion suggests that the Sphinx and its flanking temples were built as long ago as 10,500 BC, when Egypt last had a wet climate towards the end of the Ice Age.22 The Vernal Equinox was then in the constellation Leo, and Robert and Graham suggest that the Sphinx was built to face its counterpart in the sky. Furthermore, the orientation of the Belt stars to the Milky Way corresponds to the Pyramids' in relation to the Nile - not when they themselves were built, but when the Sphinx was carved out 8000 years before.
In 10,500 BC, as far as we know, the Nile delta was inhabited only by hunter-gatherers, wholly lacking the technology to carve out the Sphinx and build the temples in 200-ton blocks. In a previous book Graham Hancock tried to get round this by suggesting a world-spanning civilisation, unknown to us, which lasted over 8000 years and was based on the coast of Antarctica.23 It used to be thought that the Antarctic coast was ice-free during the Ice Age in the northern hemisphere; however, that idea had been attacked by the early 1980's15 and more recent Antarctic surveys continue to stack up evidence against it. And it's very hard to believe that such a world-spanning, long-lasting civilisation would leave so little evidence behind.
Graham couldn't attend the Edinburgh seminar, but he and Robert were both in Glasgow three weeks later and I was able to arrange a continuation, in which we went to the planetarium at the College of Nautical Studies. First I showed them what Alan Evans and I had discovered, and when they saw the galactic alignment at Stonehenge I, Robert Bauval made an extraordinary remark, which I'll come back to in a moment.
Then, holding the date c.2700 BC, we shifted to the latitude of Giza, and verified Robert's calculations for "The Orion Mystery". It had never occurred to him to do so in this way, and he was as moved as I had been at seeing the layout of the ancient skies for himself - especially since everything he had calculated was confirmed. So too were the "Keeper" calculations for 10,500 BC, Leo, Orion and the Sphinx, when we moved the setting back to that date. When the Sun rose below Leo at the Vernal Equinox in 10,500 BC, Orion was on the meridian, and the orientation of the Belt stars to the Milky Way matched that of the Giza pyramids to the Nile 8,000 years later. Whatever its significance, that claim is true: we saw it with our own eyes, re-enacted.
But when I showed the galactic orientation of Stonehenge I, and explained what it might mean in terms of an ET landing, Robert's show-stopping remark was, "It's the same at Giza in 10,500 BC, we just didn't know what it meant." Now the time had come to verify that. Once again, if it was true at all, it would be true once a day, every day, at that latitude and date. So, just by letting the stars wheel on, we verified it at once. At Giza, in 10,500 BC, due to the effect of precession, the same galactic relationship existed as at Stonehenge c.2840. Once a day, the sky took up the same Fig. 6 configuration, with the galactic pole in the zenith and the plane of the Milky Way coinciding with the horizon. We saw it for ourselves: like a galactic 'compass rose' at each location, but separated by eight millennia in time.
But in that case, what was happening then at Stonehenge?
We kept the date at 10,500 BC, and the custodian took the planetarium 'back up' to the latitude of Stonehenge. Having no idea what to look for, once again we just let the stars wheel freely around, through a normal day. And Epsilon Boötis went through the zenith! It was doing that daily in 10,500 BC, when the galactic alignments were in force at Giza, and the effect of precession on it, over the next 8000 years, was to bring it back to the Stonehenge zenith, as an optical marker for the same galactic alignments at Stonehenge itself when Stonehenge I was created. Unless it's all coincidence, it can only mean that the events of 2840-2500 BC represented a return to both sites. And the first, 10,500 BC date goes along with the 'approximately 13,000 years ago' given by Arcturus's position in that first map of my 1973 'translation', fig. 1(A). If that map meant anything, it would have to be as a time marker, not a navigational reference as I thought.
It still isn't Category A evidence, the artefact of indisputably extraterrestrial origin, nor the Category B anomaly that leads us to it. In this context, Category C might stand for 'circumstantial'. But I can't believe that all those circumstances are coincidental; these multiple high-tech astronomical alignments are, in my opinion, the best evidence for Past Contact ever put forward. The synergistic combination of our research with Bauval and Hancock's has convinced me that we're on the track of something big.
It left two questions to answer:
1. What about the Green Children?
In the September 1996 Analog I suggested Past Contact in 12th century England. Is there a connection? There's one I pointed out in that article. The latter half of the 12th century AD featured the most violent solar activity since the Bronze Age, indicated by aurorae, carbon-14 ratios, tree-rings etc.24 And that previous peak was a triple one, between 2700 and 1800 BC, covering the building of Avebury, the Pyramids, Stonehenge II and Stonehenge III. It may be coincidence; but it's interesting that it was the case in both historical periods which I'd consider candidates for Contact events.
Even more remarkably, however, Alan Evans discovered that during the crucial years of the 12th century, between the Second Crusade and the fall of Jerusalem to Saladin, Jerusalem too had the same galactic alignment as Stonehenge I and Giza in 10,500 BC. At that point, the three enquiries – in the three very different areas of ancient positional astronomy, mediaeval history and the 1920s radio echoes – are actually three aspects of the same enquiry. It’s still circumstantial, all of it, but it looks as if it may add up to something very significant.
2. So what about the Space Probe?
Optical searches of the Lagrange points in the late 1970s found nothing. But in April 1995 Dr. Duncan Steel drew attention to the discovery, at Kitt Peak in Arizona, of a most unusual asteroid designated 1991 VG. In December 1991 it passed Earth at a distance of only 485,000 miles. Its diameter was estimated at 9-19 metres, assuming that it was made of one of the more common asteroidal rocks. However, observations at closest approach suggested "strong, rapid brightness variations which can be interpreted as transient specular reflections from the surfaces of a rotating spacecraft".25
During the space age 1991 VG would have passed only twice before, in February-March 1975 and in mid-1958 - possibly 1959, if the 1975 approach altered the orbit. Nothing that big was launched in 1958-59, nor in 1975; the European Helios 1 was launched in December 1974, but its carrier's upper stage did not escape from the Earth into orbit round the Sun. Perhaps, instead, 1991 VG was orbiting Earth then, until it was 'discovered' and moved away before anything more serious happened.
But when it comes backin 2017, let's hope that a major attempt is made to look at it. The solar-sailing 'Comet-chaser' Gordon Ross and I suggested here would be ideal,26 but it can be done by conventional means: NEAR, the Near Earth Asteroid Rendezvous, is to orbit the asteroid Eros shortly, and Europe's Rosetta probe is to do the same with a short-period comet after 2000; NASA's Deep Space 4 will reach Comet Tempel in 2006, and a Japanese probe will reach asteroid Nereus the same year. 1991 VG should be next on the list.
1. Duncan Lunan, 'Space Probe from Epsilon Boötis?', Analog XCII, 5, 66-84, January 1974.
2. - , 'Long-Delayed Echoes and the Extraterrestrial Hypothesis', Journal of the Society of Electronic and Radio Technicians, 10, 8, 180-182, September 1976.
3. Ronald N. Bracewell, 'Manifestations of Advanced Civilisations', in John Billingham, ed., "Life in the Universe", MIT Press, 1981.
4. James Strong, "Flight to the Stars", Temple Press, 1965.
5. George Sassoon, 'A Correlation of Long-Delay Radio Echoes and the Moon's Orbit', Spaceflight, 16, 7, 258-265, July 1974.
6. Anthony T. Lawton, Sydney J. Newton, 'Long Delayed Echoes: the Search for a Solution', Spaceflight 16, 5, 181-187, May 1974.
7. Robert A. Freitas, Jr., Francisco Valdes, 'A Search for Natural or Artificial Objects Located at the Earth-Moon Libration Points', Icarus 42, 442-447 (1980); 'A Search for Objects near the Earth-Moon Lagrangian Points', Icarus 53, 453-457 (1983).
8. James R. Wertz, 'Interstellar Navigation', Spaceflight, 14, 206-216, June 1972.
9. Duncan Lunan, "Man and the Stars", Souvenir Press 1974; US editions "Interstellar Contact", Henry Regnery Co., 1975, "The Mysterious Signals from Outer Space", Bantam, 1977.
10. Gerald S. Hawkins, "Stonehenge Decoded", Souvenir Press, 1966.
11. A.Thom, "Megalithic Sites in Britain", Oxford University Press, 1967; "Megalithic Lunar Observatories", OUP, 1971; (with A.S. Thom), "Megalithic Remains in Britain and Brittany", OUP, 1978.
12. Duncan Lunan, 'Solar Events at Sighthill', Griffith Observer, 50, 6, 2-11, 20, June 1986.
13. J. Gall Inglis, Arthur P. Norton, "Star Atlas", 14th edition, Gall & Inglis, 1959.
14. Dates for the various construction phases at Stonehenge remain in some dispute; Aubrey Burl, "Prehistoric Avebury", Yale University Press, 1979, puts the earliest construction around 2800 BC, as do the Thoms (ref.19), with no further work until c.2150 BC. Some recent reports compress the building into one continuous process; yet there seems to be clear evidence for an interruption, during which the Stonehenge I ditch silted up, although its discoverer put the event strangely far back, dating it at 3100 BC, well before the starting dates given elsewhere. (Christopher Chippendale, 'Life around Stonehenge', New Scientist, 101, 1404, 12-17, 5 April 1984).
15. Fred Hoyle, "Ice", Hutchinson, 1981.
16. Sean O'Neill, 'Totem Poles Give Pointer to Siting of Stonehenge', The Daily Telegraph, 28 June 1996.
17. Robert Dawson Scott, 'Silent Power from a Time of the Ancients', The Daily Telegraph, 10th January 1997.
18. Nigel Hawkes, 'Stonehenge Dating Dispels Icesheet Theory', The Times, 5 December 1994.
19. A. Thom, A.S. Thom and A. Thom, 'Stonehenge', Journal for the History of Astronomy, 5, 13, 71-90 (June 1974).
20. A.C. Evans, 'The Three Dimensional Grid', paper presented at 'Heresies in Archaeoastronomy', Edinburgh International Science Festival, 16th April 1995.
21. Robert Bauval & Adrian Gilbert, "The Orion Mystery", Heinemann, 1994.
22. Robert Bauval & Graham Hancock, "Keeper of Genesis", Heinemann, 1996.
23. Graham Hancock, "Fingerprints of the Gods", Heinemann, 1995.
24. John A. Eddy, 'The Case of the Missing Sunspots', Scientific American, 236, 5, 80-88 & 92, May 1977; 'The Maunder Minimum', Science, 192, 4245, 1189-1202 (18th June, 1976.)
25. Duncan Steel, 'SETA and 1991 VG', The Observatory, April 1995; 'Of Asteroids and Aliens', The Skeptic, 15, 1, 9-10 (1995).
26. Duncan Lunan, 'Keep Watching the Skies!', Analog, CXIV, 12, 70-84, October 1994.
27. I.E.S. Edwards, "The Pyramids of Egypt", Penguin, 1947.