by Andy Lloyd
So, by a process of elimination we are left with just two candidates among the recognized worlds orbiting our sun: Mars, and the Earth. This is the classic argument supported by the notion of the ‘habitation zone’. But there may be nooks and crannies on other planetary bodies that could hold liquid water. As implausible as this may first seem, we must consider the moons of the outer planets.
The vast majority of these distant moons orbiting the gas giants are barren rocks. However, we now know that several of them have features suggestive of frozen oceans. This has provided an extension of the solar system’s ‘habitation zone’ to the realm of the gas giants Jupiter and Saturn. Life could readily await discovery on one or more of their numerous moons.
The chances for future discoveries of life have increased because biologists have been able to show that life is able to withstand extreme conditions with unexpected ease in parts of the Earth once deemed "uninhabitable".3 The discovery of veritable ‘oases’ of water scattered widely through the solar system has increased the potentialities further: where there is liquid water, there is the potential for life.
The 4 major ‘Galilean’ moons of Jupiter are ‘warmed’ by the gravitational influence of the gas giant itself, and, among them, Europa almost certainly boasts a liquid water ocean below its icy crust.4 The tidal effect produced by the parent planet internally warms Europa and shows that our traditional assumptions about what is thought to constitute the habitable zone around a given star have been ‘oversimplified’.5 Distance from the sun is not the only factor at play, even if it remains the most important.
Moons of Life?
The Galilean moons of Jupiter offer good conditions for the emergence for life because the vast bodies of water under their surfaces are warmed by gravitational and tidal effects induced by their massive parent. Io is the closest moon to Jupiter, and the effect is extreme enough to make this moon highly active volcanically. Europa is the best candidate for life, and a deep ocean seems to lie below its frozen surface which may contain twice as much water as all the oceans of Earth combined!
Europa looks like a scratched and colourful billiard ball from space, and NASA plans to explore the geography of this moon by radar and probes.4 The two further Galilean moons, Callisto and Ganymede, may also be hiding secret oceans below their frozen surfaces. Yet these worlds are five times further away from the sun as the Earth.
Is it possible to move even further away from the sun and apply the same principles to moons of the more distant, and colder, planets?
The main moon of the beautiful ringed planet Saturn is Titan, a smoggy, cold world covered in hydrocarbons. We now know that Titan has oceans of liquid hydrocarbons on its surface, mostly consisting of methane. It also has landmasses and coastlines, familiar features to us on Earth. Liquid methane goes through a similar dynamic process there as water does here; evaporation, precipitation, run-off and drainage occurring below Titan’s surface.6 Scientists speculate that there may be water buried beneath the surface of Titan, warmed by Saturn’s tidal forces. It’s perfectly possible that water might ‘geyser’ up into the organic molecule-rich oceans, and allow the building blocks of life to emerge.7
One day, when the sun begins to wind down and expands to a red giant, Titan will become the most valuable real estate in the solar system. For a short time Titan will become the new Earth, warmed by a massive red sun that has already driven off all of the waters of the Earth.8 We have 4 billion years to wait before that happens, though.
But at the present time, Titan seems too inhospitable a climate for complex life, despite the presence of liquid water. The dark atmospheric smog and great distance from the sun will stop photosynthetic reactions taking place, preventing a meaningful ecosystem from developing on the surface of Titan. But there may be the presence of ‘extremeophiles’: Life that can evolve and exist at the limits of environmental conditions. After all, the building blocks for the formation of life exist on Titan, and a dynamic environment may have already created the spark that is needed for life to begin.
The major moon of the very distant planet Neptune is called Triton. It has no atmosphere to speak of, and lies at the edge of the planetary zone around our sun. Its surface is laden with dark organic materials and nitrogen ices, some of which appear to have occurred as snowfall near the equator. It is simply too frigid at this distance for Triton to hold onto an atmosphere, despite tidal warming by Neptune.
Any atmosphere it might once have, had precipitated out onto the surface as ice.9 At this distance there is simply too little heat to create the conditions for life, even with the tidal warming effects by Neptune. Liquid water is not available out here, and even the most optimistic commentator must doubt whether the extended habitation zone goes as far as Neptune, some 30 times the distance of Earth from the sun (known as 30 Astronomical Units).
Comets
This seems to mark the boundary for the potential for life in the solar system. Beyond Neptune and Jupiter lie two collections of comets. The first is a belt very similar to the asteroid belt between Mars and Jupiter, which surrounds the planetary zone. It is known as the ‘Edgeworth-Kuiper Belt’, and the discoveries that are taking place about its nature will form the basis for some of this book.
The second collection of comets is a far more distant one which surrounds the solar system. This ‘Oort Cloud’ is a deep spherical layer of comets which are finely distributed, some of which occasionally fall back towards the sun as long-period comets. There appears to be a substantial gap between the Edgeworth-Kuiper Belt and the inner Oort Cloud, where few comets trespass. Again, an explanation for this can be found in this book.
It has been argued that comets carry with them the seeds of life, and this may well be so. Such ideas form the basis for Panspermia, a theory that involves the universal spread of life via such intra-and interstellar travelers. But even if comets hold onto bacterial spores, they do not provide conditions for that life to actually get started. Instead, ‘life’ rests here in a state of suspended animation.
Our knowledge about what celestial bodies might lurk beyond the orbits of Neptune and Pluto is still in its infancy. As the distances from the sun become ever greater, our ability to detect dark bodies ‘out there’ diminishes rapidly. The Harvard astrophysicist Matthew Holman recently noted that a Mars-sized planetary body could easily have escaped detection even if it was located as close as 200AU away.10 Given that one Astronomical Unit (A.U.) is the distance between the sun and the Earth, then this is a considerable distance indeed. An undiscovered planet could be orbiting the sun beyond this point and we could still be none the wiser, despite the advances in detection methods.
This is because the brightness of an object depends on its distance from the sun to the fourth power.11 The luminosity of an object rapidly falls away with distance. This is why the immense planets Uranus and Neptune cannot be seen in the night sky with the naked eye. As the distances increase further, into the Edgeworth-Kuiper Belt and beyond, the potential for a substantial undiscovered planet increases with it.
The reason why this is an important question is that there is a possibility that our extended habitation zone could find itself out among the comets. If something is out there and is significantly massive, then it may generate its own heat. A planet that size would have to be more massive than Jupiter.
Common sense would lead us to believe that scientists should surely have discovered such a world by now. But that is not necessarily the case. Remember, luminosity drops off sharply with distance, and finding anything ‘dark’ among the comets is a real challenge for astronomers, even with the largest telescopes.
Such a massive planet has been proposed before by various scientists, and their ideas considered seriously by the scientific community. It is not the realm of the fantastic at all.
The Perturber
There is indirect evidence that a body greater in mass than Jupiter is orbiting the sun. It has been termed the ‘Perturber’, because of its alleged e
ffects upon comets within the distant Oort Cloud. It may be sufficiently large to fall into the category of ‘failed stars’ known as brown dwarfs.12, 13, 14 These bodies are too small to have become stars, and may have been splintered off-shoots of stellar matter ejected from primordial star systems. They burn brightly when young, and are termed ‘light-emitting planets’ in the early stages of their lives.15
Over time they become dark planetary ‘embers’; warm bodies that emit little or no light. The astronomers who have speculated about the existence of a small brown dwarf circling the sun consider it to be similar to Jupiter, although several times more massive. This is not the stuff of science fiction, but of very real scientific speculation.
Little is known about these bodies as so few have been directly detected elsewhere. Their warmth and ability to emit light remains a controversial subject, but as their mass becomes greater they become more star-like, and less planet-like. In the midst of this murky area of knowledge lies what I have termed a ‘Dark Star’, a hybrid planet/star whose warmth can incubate life whilst simultaneously remaining difficult to detect.16
Since astronomers first started detecting and studying brown dwarfs directly, their stellar properties have proved surprising given their relatively small size.17 To give some indication of how our knowledge has progressed, it is interesting to note that it was once thought that life could exist actually on a brown dwarf.18 This idea has been discredited, but it has been acknowledged that life might be possible on a moon orbiting one.19 The brown dwarf’s moon would be warmed by gravitational tidal effects as well as the warmth emitted directly by the failed star itself.
The implication of this is dramatic. If the ‘Perturber’ were to be detected directly it could open a new chapter in the search for life in the solar system. Even at the distances from the sun involved, a small brown dwarf among the comets could provide a habitable environment on its own moons. This is not dissimilar to the picture provided by the moon Europa orbiting Jupiter. But a brown dwarf’s moon has the added advantage of basking in the ember-glow of this failed star.
This is a crucial point to take on board. When we looked at the case of Europa we considered how life might exist in a liquid ocean under its surface. This ocean was warmed by Jupiter, and not just the sun. Yet, Jupiter is just a regular planet.
Out in the comet clouds the sun’s warmth is practically negligible. In order for life to exist on a moon orbiting a Dark Star, the brown dwarf itself would not only have to be more massive than Jupiter, but it would need to emit its own heat as well to warm its inner moons. Yet, it couldn’t be too big or its electro-magnetic radiation would be readily detectable from Earth.
It would have to be warm, but fairly dark. Yet, it may still glow enough to light its own moons, rather like the glow of the embers of an old fire can dimly light a room in winter. Because, as we know, luminosity drops off with distance. Beyond its system of moons, the Dark Star would become all but invisible in the night sky.
This concept is a central plank of my Dark Star Theory. It raises the possibility of extending the habitable zone into the comet clouds, and adds a sense of urgency to the otherwise rather academic pursuit of discovering planets beyond Pluto. The hunt for Planet X becomes the hunt for life.
Detecting Planet X
Although such a planet has so far evaded direct detection in our solar system, similar entities have been found orbiting neighboring stars. How can this be, given how much further away those stars are? Surely, if we can find these bodies around distant stars, we should be able to see one very clearly around the sun? Strangely, perhaps, it is the other way around; the planets located around other stars are easier to spot. This is because they are detected in a different way.
The means of detecting dark planetary bodies around other stars involve indirect techniques. These include the measurement of the star’s ‘wobble’ in space, as its position is influenced by the massive body interacting with it. This wobble may be very slight, but it is enough for the modern astronomical techniques to detect. Calculations based on these observations can then give information about the size and orbit of the planetary body orbiting the star in question. Sometimes the light of the star will be seen to dim slightly, and this is attributed to the planet moving between the star and us, effectively blocking out a minuscule amount of the star’s light.
These can be conclusive observations, enabling astronomers to confidently claim the existence of giant worlds around neighboring stars in the Milky Way. But the same techniques cannot apply to our own sun. If the sun is wobbling in space because of its companion, then the effect is negligible because of the Dark Star’s immense distance from it.
This contrasts with discoveries of extrasolar planets whose orbits are all similar to the inner planets of our solar system. We know that the sun is moving in a slightly odd direction compared with its neighbours. It is heading towards the Solar Apex, near the star Vega in the sky, and this may turn out to be coincident with the position of the Dark Star. But, this does not provide evidence in itself for the existence of this possible ‘binary companion’. So, to find such a body around our own sun we must rely upon different techniques, even though it is much closer to us than the stars studied by planet-hunters.
Often, the orbits of the extrasolar planets, or ‘exoplanets’ are eccentric. Yet, they can remain an intrinsic part of stable planetary systems.20 This was a surprising discovery, but is in keeping with long-standing speculations about the nature of our own Planet X. These speculations stem from some rather remarkable theories generated in the second half of the 20th Century.
Certain researchers, including Immanuel Velikovsky and Zecharia Sitchin, proposed that we could learn a lot about ancient astronomy from ancient myth. Their theses worked on the principle that before writing was developed, scientific knowledge was already being handed down from generation to generation -- but that it took the form of myth. If one then worked backwards from the myth, and understood the ‘gods’ to be equivalent to cosmic bodies, like the sun, Moon and planets, then the myth would indicate ancient models for creation of the solar system.
Careful scrutiny of certain ancient myths shows a fairly precise understanding of the solar system among ancient peoples, possibly reflecting advanced observations thousands of years ago. But the myths also contained additional elements that did not equate with our current knowledge of the solar system. An important planet was missing from the myth, one that stood as a central pillar in the creation myths. I believe that this body is a Dark Star, which means that the sun has a binary companion, albeit a rather diminutive ‘kid brother’.
The possibility that such a body has a highly eccentric orbit would readily explain how it is currently very difficult to detect, yet has been observed in the sky during history and prehistory, becoming an established part of humanity’s mythological inheritance.
A planet the size of a small brown dwarf might approach the outer planets, or move through the distant Edgeworth-Kuiper Belt, without causing orbital mayhem. In times gone past, it may even have moved among the planets nearer the sun, perhaps through the Asteroid Belt; a zone which may once have been the home of another, long-destroyed world. This may seem incredible, but it has been shown that a small brown dwarf could actually move directly through the solar system without disrupting the other planets.
Computer simulations have shown that a planet as massive as 10 Jupiters would have no discernible effect upon the other planets if it moved among them.21 This surprises many who would naturally imagine that the passage of a large planet through the solar system would have a catastrophic effect on the other planets, including Earth. However, this is not necessarily the case.
Even though this is a possibility, I now doubt that the Dark Star moves through the planetary solar system during our current era. Instead, it treads quietly through the more distant Edgeworth-Kuiper Belt during the closest approach of its orbit. It seems to be leaving the cosmic equivalent of dirty footprints in the sno
w out there. It may bring with it other planets, though, that do move closer to us and become observable. This is another theme we shall be exploring in this book, one that will allow us to integrate science with myth in a rather elegant way.
The creation myths that we have spoken of here indicate that this Dark Star did move among the planets in the distant past, and that the effect of its transit among these familiar worlds was, in some cases, catastrophic. Again, there is anomalous evidence in the solar system to support such a contentious argument. It seems that its catastrophic incursion a billion or so years ago was confined to that brief, but traumatic period, and that it has migrated out to more tranquil waters since.
The strong-headed god who stormed the solar system soon after its creation has wizened up and now keeps its distance. Yet, the glory days of its youth are evidenced every time we look at the Moon in the night sky. Armed to the teeth, our fiery young god brought with it a devastating array of weaponry.
Mythology and the Dark Star
Let us imagine for a moment that a brown dwarf moved through the solar system billions of years ago. We can consider this seriously because of the evidence in the solar system that multiple catastrophic events occurred about 3.9 billion years ago, about 500 million years after the birth of the solar system. The Earth and Moon were literally pounded by massive bodies, whether asteroids or comets.
The Moon still shows the scars of this event long ago, which is known as the ‘late, great bombardment’. This is because the surface of the Moon is extremely ancient. Other similar bodies in the solar system also show this traumatic pattern of cratering.