The choice of OSIRIS-Rex as the next NASA space program has come as a surprise, and disappointment to some. Although comets at first glance may
not appear as sexy as the big planets, they have increasingly over recent years raised the expectation that they may hold the answers, not only to the
origins of our planet and solar system, but also to our place within it. This mission, could, quite possibly, give a definitive answer to the
question of whether life on Earth was facilitated by extraterrestrial visitors.
We have been aware of these celestial visitors since, at least, antiquity, the Chaldeans called them ‘dust clouds’ ascribing them with the power
to prophesise disasters, while the Chinese began recording their visits in their annals from 613 BC.  According to NASA guidelines, in order for
an object to be classified as a Comet, it must be comprised of at least 85% ice, however there are exceptions, and many objects previously
classified as asteroids are being reconsidered as ‘dead’, or extinct comets.
When observed through a reflector, a comet can be seen to be made up of three separate parts. The Core is a frozen conglomeration of gases, rocks,
metals and other matter, usually extending to a few kilometres across, while the Coma is made up of nebulous matter and can have a radius of anywhere
between 50 and 100,000 kilometres, sometimes more. The third component is the Tail, which is caused by the transmutation of core-ice as it interacts
with the Sun. Comet tails have been known to stretch for over a million kilometres .
Comets are usually classified as either Short or Long Period. Short period comets are believed to originate in the Kuiper belt and have orbits
ranging from a few years to hundreds of thousands of years. Long period comets however are believed to originate in the Oort Cloud and are sent
plunging towards the Sun through ‘gravitational perturbations’ caused by the outer planets of the Solar System or passing stars . These comets
may pass through the Solar system only once before being cast out into interstellar space, but many make return visits. It is usually the debris from
the coma or tail that comes into contact with our atmosphere, falling to Earth in the form of meteorites. Those examples that have been recovered can
be as small as a fist, sometimes smaller, or weigh several tonnes. The latter though is much rarer.
In 1980 a team from the University of Berkeley led by physicist Luis Alvarez, began finding a fine layers of Iridium dust, a very rare metal under
usual circumstance, at sites across Northern Europe. These samples were dated to the end of the cretaceous period, and Alvarez’s team proposed that
the mass extinction that ended the cretaceous period may have been caused by an asteroid, several miles in diameter impacting Earth which generated
the energy equivalent of some billion Hiroshima’s, creating a dust cloud so dense, that it plunged the entire biosphere into a ‘perpetual
The Berkeley team initially speculated that this darkness must have persisted for several years to cause the widespread devastation of life that the
cretaceous extinction represents, it was soon realised that only months had been needed to set in motion a process of ‘Biotic Crisis’, that would
lead to the selective
extinction that destroyed the megasaurs but permitted smaller life-forms, like the small mammals to which we owe our
existence to survive.
Samples of layers taken from sites around the world began to uncover a consistent pattern of microscopic debris that came to be referred to as the K-T
Boundary, confirmed a globally affective event had occurred around 65 million years ago. Alvarez found Iridium at 100 of the sites studied. Glass
spherules, formed by extremely high temperatures, were found at 70 sites, and shocked quartz, another indicator of extreme heat and pressure, was
found at 30. All that was needed now, was an impact site.
The Chicxulub crater, and an array of smaller craters, were identified as dating from the right period. It was now, almost certain in the minds of
geologists that Earth had been hit with a shower of asteroids around the end of the Cretaceous period and that this had at least contributed to the
mass extinction. The shockwaves of these impacts, it was considered, could have led to the creation of the Decca Traps, which would have further
driven the planet into Biotic Crisis.
Hot on the heels of the University of Berkeley, David Raup and Jack Sepkoski, of the University of Chicago, announced in 1984, that Earth had
experienced in excess of twenty extinction events in the Phanerzoic. All of them, concluded Raup and Sepkoski, including the ‘Big Five’, had
occurred at ‘regular’ 26 million year intervals. The only source for such regularity, they proposed, was if those extinctions had been
stimulated by regular bombardments from space. According to Leakey and Lewin, in The Sixth Extinction, it is probable that 60% of
extinctions have been caused by an asteroid or comet.  If this regularity of major impacts is to be taken as a conclusive pattern, we are between
10 and 13 million years from the next such ‘attack’.
According to Professor Peter Ward, chair of the international panel on cretaceous-tertiary extinction, and editor of, ‘Global Catastrophes in Earth
History’, had this impact not taken place when and where it did, that mammals, and more particularly humans, may never have evolved.
Craters of varying sizes and ages had attracted scientific investigation prior to 1984, but Alvarez’s conclusions intensified interest. A number of
craters, previously misidentified as long-dead volcanic caldera and were reappraised. Others, were so vast, that they could only be seen from above,
or were concealed by the movements and debris of time and only revealed using satellite imaging technology. In 1610 when Galileo Galilei first
recorded his observations of the Moon through a telescope in The Sidereal Messenger, he noted that her surface was covered with ‘spots’, he
disregarded the ‘great’ or ‘ancient’ spots as he called them, and instead focused his attention on the lesser spots, which though smaller,
appeared “so thickly scattered that they sprinkle the whole surface of the Moon, but especially the brighter portion of it.”  Despite the
constraints of seeking evidence of regular impacts on a planet of which two-thirds is covered in water, geologists began to realise, that the face of
the Earth, was, potentially as pock-marked as that of her sister, the Moon.
The Suavjarvi crater, at approximately 2.4 billion years old, is, currently, the oldest known impact site. Though not the biggest, at a mere 16
kilometres across, it is dwarfed by the second oldest, about 2 billion years old, the Vredefort crater in South Africa, which is a massive 250 to 300
kilometres across, with the impact object itself estimated to have been somewhere in the region of 10 kilometres wide. Here too, it has been
suggested that the shockwave was so powerful, it may have contributed to the creation of the Bushveld Igneous Complex and the Witwatersran Basin..
The Sudbury Crater was created some 1.849 billion years ago, leaving a crater 62 by 30 kilometres, and 15 kilometres at its deepest. The impact
caused debris to be carried as far as 800 kilometres, over an area of 1,600,000 square kilometres. The soil is particularly rich in minerals and is
considered the best agricultural land in North Ontario.  Also in Canada, this time Quebec, is the Manicougan Crater, a relative baby at only 228
million years old, but boasting a crater 100 kilometres in diameter.
Despite the seeming predictability of the major impact once every 26 million years, it has become increasingly clear, that the planet has been hit by
some, lesser and more locally catastrophic impacts more recently which may have contributed to our current Biotic Crisis. According to Leakey and
Lewin; “It was a great philosophical breakthrough for geologists to accept catastrophe as a normal part of Earth history.” 
Modern science, founded on principles gestated in the Renaissance and Enlightenment and implement in the Age of Reason, had come to believe that
science could find order, and eventually overcome
nature. Accepting the idea that extinction on Earth could be caused by a sudden catastrophe,
from an external
source was a difficult pill for some to swallow, as David Raup explains “...we’re taught that this sort of deus ex
explanation for natural events should be avoided because it constitutes a return to the mysticism of the early days of science.” 
The Barringon Crater in Arizona, was created by a meteorite that hit Earth with an estimated energy of 10 mega-tonnes. The meteorite that has been
recovered is composed mostly of nickel and iron, measured 50 metres across and created a crater 1,200 meters in diameter and 170 metres deep. It came
to Earth 50,000 years ago. 
The Rio Cuarto Crater in Argentina first identified in 1990 by amateur astronomer Captain Lianza of the Argentinian Air force, raised new questions
about impacts. Comprising of 10 craters, it is theorised that the object entered the Earth’s atmosphere at an angle of 15 degrees, creating an
impact site that resembles the spread wings of a butterfly. The meteorite, most likely, a Carbonaceous Chondritic, on impact created a ‘mountain of
fire’ 10 kilometres wide and 50 kilometres long, fragmentation of the object on impact, is the likeliest cause of the secondary craters. 
Carbonaceous Chondrites are believed to be rare, representing only 4.6% of all meteorite falls and are categorised into seven groups based upon
composition, but most contain an array of organic chemicals, which it is suspected, that unlike most comet material, has not undergone super heating
(exposure to temperatures greater than 200 degrees Celsius).  Given the presence of such volatile elements, the energy of entry into our
atmosphere, is highly combustive. Would this sort of impact, combined with a correlation with volcanic activity, and the hurricane force winds often
associated with such impacts, be sufficient to plunge the planet into Biotic Crisis?
The Younger Dryas occurred between 12.9 and 11.5 thousand years ago, when the higher latitudes of Northern hemisphere saw a rapid return to glacial
conditions for a period of about 1000 years. Temperatures in some areas are believed to have fallen by as much a 15 degrees Celsius. 
Controversially, in 2008, a team of archaeologists reported that a charcoal rich layer had been found at 50 Clovis-age sites across the North American
continent. Microscopic examination of soil siftings from this layer, reported in the January 2009 issue of Science
, showed the presence of
materials, such as nano-diamonds, metallic spherules, and
Iridium, found to be consistent with an impact event, and that this could
been the cause of the extinction of the mega fauna. “These diamonds provide strong evidence for Earth’s collision with a rare swarm of
Carbonaceous Chondrites or comets at the outset of the Younger Dryas cool interval, producing multiple airbursts and possible surface impacts, with
severe repercussions for plants, animals and humans in North America.” 
In 2010 the theory that the Younger Dryas was caused by an impact event was dismissed when those results could not be replicated independently,
although there has been no other explanation for the charcoal layer. Is it possible that while not suffering the direct impact of a meteorite, that
the area was ignited by a fireball as it passed over to impact in the sea?
Carbonaceous Chondrites though potentially very destructive do not often leave obvious physical traces, as they usually break down prior to impact,
and what debris that does fall to Earth is susceptible to weathering. Several examples have been recovered from Antarctica, and five others have been
observed falling and subsequently recovered. Three of these five (Ivuna, Orguiel, Alais, Tonk and Revelstone), it was announced in March 2011 contain
evidence of microfossils, although these results are as yet, to be independently verified. 
“The recognition that mass extinctions play so vital a role in shaping Earth history was important enough in the development of evolutionary
theory. The notion that these events may be the result of extraterrestrial impact is truly compelling. We are forced to leave behind a Darwinian
world that is shaped by forces we can understand and identify with in our daily existence, and accept one that is the hapless victim of a fickle
universe. Gone is an image of the flow of life as smooth and predictable, with humans it’s inevitable culmination; its replacement is a world that
is erratic and unpredictable, and in which our place is achieved through a large slice of luck. Catastrophism is back with us, and it is real.”
In Australia, the Henbury craters have been dated to 5000 years ago, it is suspected to have broken up in the atmosphere, creating around 13 or 14
craters of varying size and several tonnes of iron and nickel fragments have been excavated from the site. Older sites, long known about, and part of
local mythology and the verbal tradition, can perhaps now be reassessed and placed into a wider body of our understanding.
The Kamil Crater in Western Egypt, 45 metres wide and 10 metres deep, was created by an impact 3,500 years ago. The Mahuika Crater at Snares Island
off southern New Zealand, was with the aid of ice cores found to date from around 1443 AD, and Chinese records report a hail of “falling stones”
in the Shanxi Province that, reputedly, caused 10,000 deaths in 1490.  Looking at historical records seems to have provided the route to a number
of similar discoveries where fact may be starting to eclipse fiction.
The Kaali Crater on the Estonian Island of Saaremaa is thought to date to around 660 BCE and been caused by a meteor with a mass between 20 and 80
metric tones with an impact velocity of 10 to 20 kilometres per second. When it was about 10 kilometres above the Earth it broke up, producing 9
craters, the smallest of which is only 12 metres in diameter and the largest, at the bottom of which is Kaali Lake, is 110 metres in diameter and 22
metres deep, the craters are all within 1 kilometre of each other. The energy from the impact would have been equivalent to Hiroshima. Trees within
a six kilometre radius were razed. 
In Estonian mythology, the lake is considered sacred and was, sometime around the Iron Age, enclosed by a stone wall. The Fins tell a tale of Louhi,
an evil wizard who steals the sun and fire causing total darkness. Ukko, the god of the sky, orders that a new sun be made by the Virgin of the Sky.
Somehow, the spark, from which the new sun was to be made, falls to the Earth behind the Neva River. The heroes of the tale rush to the fire and
light their torches, thus returning light to their people. It has been proposed that Saaremaa may be the Thule of legend, the Finnish word for fire
The Lonar crater in India was also first presumed to be a volcanic caldera and is also considered sacred by local people. The salt lake that it
houses has a mineral content much richer and quite unique from the other ‘natural’ salt lake found in India, and tests conducted in the first half
of the 19th century concluded, “it is practically certain that the Lonar salts are derived from an unknown source in the bed of the lake.” 
Another potentially interesting feature of this site, and the lake it contains, is the presence of Nitrogen fixing organisms in the water that can
only live in conditions of pH-11. Due to a number of difficulties with the site, dating has been inconclusive and estimates vary from a few thousand
years to a few hundred, a situation mirrored at the Wabar Craters in Arabia. 
First noted by the west in 1932, when Harry St John Philby stumbled across them while looking for the site of the legendary Ubar, or Iram of the
Pillars which had been ‘smote’ by God when King Shaddad ignored the warnings of the prophet Hud. According to Islamic tradition, God drove the
city into the sands, ‘never to be seen again ’. Philby soon realised that Wabar was not Ubar, and guessed that the five craters he observed
were long dead volcanic caldera, due to the presence of ‘volcanic’ glass at the site. In 1937 Philby, by then in the employ of SOCAL, was joined
by a team from ARAMCO to study the site but failed to uncover anything. They returned in 1966, with a bulldozer.
The largest fragment recovered weighed 2.2 tonnes and it is estimated that that fragment alone would have had an impact energy similar to Hiroshima.
Dating the site has proved problematic, it was at first thought to be thousands of years old, but eyewitness accounts of a fireball seen from Riyadh
in either 1863 or 1891, and the rapidity with which the sands have since consumed two of the craters that Philby have appeared to confuse the
On a side note, a more likely site for Ubar has since been identified via satellite imaging technology. Adjacent to the Ash Shishar well, a point
where camel roads have passed since the third millennium BC, archaeologists have uncovered a trading town beneath the fort that currently occupies the
site. Sometime between 300 and 500 AD the town had, literally, been consumed by the sands. Like many oasis in the desert, this one, had in antiquity
been served by a natural limestone cistern below ground which had gradually dried out as the town prospered. The roof of the cavern, no longer able
to support the weight of the settlement above, collapsed, swallowing the town with it. Hazarding a guess, Hud was most likely telling King Shaddad to
stop wasting water.
The Tunguska event, is perhaps the most comprehensively documented impact event in recent history. At around 7.14 on the morning of 30 June 1908,
Russian settlers and nomadic Tungus natives observed from the hills northwest of Lake Baikal, a column of blue light, accompanied by a sound like
cannon fire. The meteorite is believed to have exploded mid air soon after entering the Earth’s atmosphere, creating an airburst with an energy
equivalent to 1000 Hiroshima’s. The witnesses provide a vivid account.
Chu Chan of the Shanyagir Tribe,
“There was a noise beyond the hut, we could hear trees falling down..then the thunder struck…The Earth began to move and rock, wind hit our hut
and knocked it over…trees were falling, the branches were on fire, it became mighty bright…as if there was a second son.” 
Russian settler, S Semenov,
“…I suddenly saw, that directly to the north…the sky split in two and fire appeared high and wide over the forest. The split in the sky grew
larger, and the entire northern side was covered with fire. At that moment I became so hot I couldn’t bear it, as if my shirt was on fire…but
then the sky shut closed, and a strong thump sounded, and I was thrown a few metres. I lost my senses for a moment…After that such a noise came, as
if rocks were falling or cannons were firing, the Earth shook.” 
80 million trees over an area of 2,150 square kilometres were felled by the blast, and it is estimated that the shockwave would have registered 5.0 on
a Richter scale. In the days following the airburst, witnesses reported glowing skies across Northern Europe and Asia. Atmospheric pressure
fluctuation were detected at the time as far away as Great Britain, and two observatories in the USA noted a decrease in ‘atmospheric
transparency’ in the following months, caused by suspended dust from the explosion. More recently, soil samples have yielded microscopic silicate
and magnetite spherules, and Iridium, across the blast zone, as well as traces of Nitrogen, suggesting that it fell as acid rain.
It was an airburst such as that experienced in Tunguska, though on a larger scale, that was proposed as the cause of the breakdown of the Clovis
culture. There have been twelve airbursts reported since Tunguska, though not of the same scale, the most recent of which exploded over the Nubian
Desert in Sudan in 2008.
Of the 4,185 known comets in our solar system only a small proportion are ever visible to the naked eye here on Earth. 1,500 of those that are, are
Kreutz Sun grazers , comets who’s orbit bring them close to the sun. Those comets that can be seen from Earth tend to be more visible because
of the tail, which is like a fragile, temporary atmosphere, created by the interaction of the comet with solar winds and radiation, but under usual
conditions, comets are quite hard to find. This is due primarily to their composition and light reflectivity. Halley’s Comet, was found by the
Giotto Space probe, to reflect only ‘4% of the light that falls on it’.  While Deep Space 1, discovered that Comet Borrelly reflects no more
than 3%.  This combined with their small size, makes them very hard to detect when out of the Sun’s more direct influence, which not only
increases the emissions of volatile gases, but illuminates the particles within the coma, making it appear much larger and brighter. The tail itself
however, points away from the sun, so it can be surmised that a comet in direct trajectory away from the sun, and towards Earth, may not have a
visible tail. Though, in modernity, we have numerous observers, from numerous angles, to ensure that such an eventuality would not go entirely
In 1994 Comet Shoemaker Levy 9 provided our first direct observation of a comet impact. The impact would eventually be nicknamed the ‘String of
Pearls’ after observers watched as the fragments, some 2 kilometres in diameter, slammed into Jupiter’s surface in a neat row. The BBC reported
that, “calculations showed that its unusual fragmented form was due to a previous closer approach to Jupiter in July 1992. At that time, the
orbit…passed within Jupiter’s Roche limit and Jupiter’s tidal forces had acted to pull the comet apart.” Seismic waves swept the planet at
450 kilometres per second. Waves from the largest impact were watched for over two hours by observers on Earth.
Jupiter may hold additional insight into the reasons for impacts, and their role in planetary development. Amy Barr and Robin Canup, planetary
scientists at the Southwest Research Institute in Boulder, Colorado have proposed that Ganymede has been hit more often than her sister Callisto, and
that this is the reason for Ganymede’s more advanced level of “maturity”. They believe that the reason for this is “gravitational pull”
which directs impacts away from Callisto, and towards Ganymede. 
In May 2001 Comet Linear broke up as it passed by the Sun. Water vapours released by Linear were sampled and found to be of the same isotopic
composition as water here on Earth.  News that must have been hardly surprising to some sky watchers.
‘Small Comets’ that had first been noted in the mid-1980s when UV Satellite images of the Earth’s atmosphere began to regularly show ‘dark
spots’ in the ‘Day Glow’ (the UV light produced when the Sun-light interacts with atmospheric oxygen). These ‘Small Comets’ seemed to
vaporise shortly after entering the upper atmosphere creating vast clouds, 100 kilometres across, of water vapour. These clouds absorb the UV light,
hence the dark spots, creating a temporary topical
barriers to UV light. These clouds can be observed to occur as often as 10 times every
minute, and deposit around 20 to 40 tonnes of water vapour each in the upper atmosphere contributing, it is estimated, one inch to water levels on
Earth every 20,000 years. 
In February 2004 the European Space Mission launched Rosetta whose probe should intercept Comet 67P/Churyumov-Gerasimenko sometime in 2014, and by
means of what is described as a “harpoon-device”, catch a ride. In the days that followed the failure of their last mission, they were keen
to emphasise the importance of this mission not only for it’s scientific, but also in obtaining reliable data that could be used to explore the
potential of “mining” comets for resources.
Not wishing to be left behind in what had the potential to be a new source of resources, on 12 January 2005, NASA launched the Deep Impact mission.
After travelling at 28.6 kilometres a second over a distance 429 million kilometres, Deep Impact separated into two sections, a fly-by probe and an
“impactor”, 174 days later as it approached it’s target, the comet Tempel1.
When the 370 kg impactor, travelling at a relative speed of 37,000 kilometres per hour, hit the comet Tempel1, it sent out a vast plume of fine dust
and ice, that contained, the equivalent of 250 million litres of water. Dr Don Yeomans, NASA Space Agency Mission Scientist, said ’We hit just
exactly where we wanted to…The impact was bigger than most of us expected. We’ve got all the data we could possibly ask for.’
Comets had previously been considered to be giant ‘dirty snowballs’, but the data from the Deep Impact mission suggest a much looser composition
of rocks, ice and dust that is described as “soufflé-like” with pockets, or weakness in the nucleus. On the surface of the comet, large
craters and three bodies of water-ice were recorded by the probe. Confirming, not only that the major constituent of comets was water, but also that
that water, at times, existed in a liquid or near liquid state.
In October 2007 amateur astrologers alerted experts to an “explosion” on comet Holmes. The comet is said to have brightened by a factor of a
million and it is estimated that the collision, probably with a meteorite, caused a loss of about 1% of the Holmes’ total mass.  It has been
theorised, and is somewhat supported by Southwest Research Institute, that in the early development of the Earth, impact events released energy that
not only activated the creation of the planets core , but also released elements that enabled the bonding of oxygen and hydrogen molecules to create
water, it is now understood that they carry water in the form ice, and that half
of the water in our oceans could have arrived here in this
way. Could other
extraterrestrial life have hitched a ride, or even evolved en route to Earth?
Professor Wickramsinghe who with Sir Fred Hoyle coined the term ‘cometary panspermia’ is working with researchers at the Cardiff Centre for
Astrobiology to study the possibility that comets could, at times, provide the conditions necessary to support ‘life’. “The watery environment
of early comets, together with the vast quantities of organics already discovered in comets, would have provided ideal conditions for primitive
bacteria to grow and multiply…These calculations, which are more exhaustive that any done before, leave little doubt that a large fraction of the
100 billion comets in our solar system did indeed have liquid interiors in the past.”
The Cardiff researchers believe that radioactivity helps to warm the frozen material of comets to create ‘sub-surface’ oceans that may preserve a
‘liquid condition’ for millions of years.
According to Bill Cutlip, who oversaw the OSIRIS-Rex proposal, “You can’t under-estimate the value of a pristine sample.” The majority of
our understanding of meteorites, asteroids, comets and other small solar system objects, comes from the destruction that they have caused when they
impact and the craters that those impact leave. Any object passing through into Earth’s atmosphere will, at the very least, be toasted and their
components essentially assimilated, either atmospherically, by fusion, or by weathering.
The Origins Spectral Interpretation Resource Identification Security Regolith Explorer
’s name covers all bases and clearly indicates the high
expectation of the many disciplines of science involved. The mission is expected to be launched in 2016 at the 1999RQ36 asteroid, with the first
samples expected to arrive back on Earth sometime around 2023. Universe Today
reported that samples were…“expected to enable scientists to
learn more about the time before the birth of our solar system, initial stages in planet formation and the source of organic compounds which led to
the formation of life.” 
It is clear though that these missions are not entirely for the purposes and furtherance of science, and it is, in the current economic climate,
unlikely that either mission would have received the go-ahead simply on biological grounds, or even, due to the implied threat of a major impact.
What has no doubt been a deciding factor are the wealth of raw materials that comets represent. One such resource that they will most likely find is
Iridium, which has almost become a signature of impact sites.
Iridium is the fourth rarest element of the Earth’s crust, and the rarest of the transition metals. Like gold and platinum, it is mostly
concentrated in areas of volcanic activity or igneous deposits and impact sites. The dense, highly corrosion metal though is forty times less
abundant than gold. About 3 tonnes of Iridium are produced annually, extracted primarily from the Bushveld Igneous System, Sudbury Crater and the
Choco Department in Columbia. A number of sources, like those in Choco, are not able to be exploited due to internal conflicts, allowing the primary
producers to control supply and therefore dictate pricing. In 2007 Iridium was valued at $440 per Troy ounce, in 2010, the price had risen to $750.
Iridium has been used in the manufacture of the radioisotope thermoelectric generators in six of NASA’s unmanned spacecraft, including Voyager. And
no doubt, Lockheed-Martin, who will be building the machinery for the OSIRIS-Rex mission, are well aware of its importance in the production of
components for long-life aircraft engines. The ability of the metal to resist most corrosives, including salt-water, while retaining its integrity at
temperatures in excess of 2000 degrees Celsius, has resulted in its widespread use within computing, scientific, electronic, automotive and electrical
equipment. Iridium can also serve as a catalyst in other manufacturing and testing processes. It’s properties and uses are, in short, diverse and
as we move further into the technological age, demand for this metal can only increase.
What OSIRIS and Rosetta are likely to discover, from a biochemical point of view is less certain. Even if NASA has found microfossils in samples of
recovered fallen meteorites, this does not tell us whether comets can sustain and carry life. They may have been dead before they began their journey
towards Earth, or died along the way, without those fresh, untoasted samples, we can only theorise. However, in recent months, there have been a
couple of significant studies that may shed a little light on what kinds of life could live on a comet.
According to a paper published in the journal Nature
on the 12th May this year, “Scientists say that they have…discovered an entirely new
branch on the tree of life.” This new branch of life was discovered by studying environmental DNA, in all
the water and near water
samples that they examined, they kept finding this ‘novel’ DNA, related to fungi, but also, clearly different. These life-forms, dubbed,
, have since been observed in a laboratory environment and seem to possess at least three stages in their life-cycle. “One is
where they attach to a host, which is photosynthetic algae. Another stage…they form swimming tails…And…the cyst phase, where they go to
sleep,” explains Thomas Richards of the Natural History museum in London. 
Then, on the 25th May another discovery in the microscopic complexity of water-borne life was reported, and this time involving bacteria that could
not only survive freezing temperatures, but also, produce them. “A Study of hailstones has found large numbers of bacteria at their cores…(which)
lends credence to the ‘bio-precipitation’ idea, which suggests that bacteria are actively involved in the stimulating precipitation. The bacteria
have protein coatings that cause water to freeze at relatively warm temperatures.” 
It was suggested by the researchers at a meeting of the American Society for Microbiology that these bacteria may have evolved to use the water cycle
to facilitate their own dispersal. “One bacterium…Pseudomonas syringae
, which expresses protein on it’s surface that encourages an
orderly arrangement of water molecules…(these) act as a ‘nucleation’ site, stimulating the formation of ice at temperatures far higher than
those normally required.”
The ice that the P.syringae
stimulate have been found to damage the walls of plants cells permitting the bacteria to gain entry to the cells
and feed from them. In 2008, Brent Christian of Louisiana State University reported finding the bacteria in samples taken globally from snowfields.
Alexander Michaud, of Montana State University found hailstones which possessed a multi-layer structure, the outer layers showing few traces of the
bacteria, but appearing in the cores in ‘high concentrations’.
The bacteria, which form into ‘bio films’ on leaf canopies, that are then lifted by updraft to the clouds, where they will eventually stimulate
precipitation, may provide some clues for the scientists at NASA of what to look for in the samples that they receive back in 2023, not only in terms
what kinds of life may be capable of living in such conditions, but also in the way in which the asteroid may have originally been created. The
nature of this bacteria and it’s relationship to precipitation has been known since the sixties.
It is these types of life forms, able to survive in the most extreme conditions that Richard B Hoover, an Astrobiologist with the NASA Marshall Space
Flight centre, has been studying for most of his career. His findings of fossils in Carbonaceous Chondrite meteorites, while still somewhat in
dispute, do indicate a life form that died whilst in a water-like substance.  And, even more recently, the European Space Agency has reported
that a proto-star, when viewed using infra-red imagining technology at the Herschel Space Observatory, can be seen to be shooting out gases from
it’s north and south poles, that once they move far enough away from the developing star, cool and become water, suggesting that such stellar
embryos may be ‘seeding’ the universe with water. 
It could almost seem as though, the Universe has decided that now is the time to reveal its most deeply held secrets, all at once. Perhaps, this, is
the real disclosure that we have all been waiting for. It is clear that alien visitors, in the form of meteorites, have been coming to our planet
since it’s very conception, but the picture that is beginning to develop, is that these visitors have not only created changes to the life on this
planet, as the result of extinctions and related climate change, but have also brought to Earth the nutrients and, equally importantly, water
necessary to sustain life. Recent finds in microbiological life too seem to support the principles of the microcosm to macrocosm, in ways previously
Leakey and Lewin propose that in times of ‘Biotic Crisis,’ such as those created by major impact events in our distant and ancient past, it has
been demonstrated that background evolution, or what is usually blanketed as ‘Darwinian Evolution,’ goes out the window, and survival, after all
that competition, comes down to luck. That, and, clade size
. In the end, what a species survival comes down, during such cataclysms, is
having enough representatives of your species in those few pockets that affords the best possibility of survival. The only answer to species
survival, therefore, is to ensure that your species covers the entire globe. An ‘instinct’ or adaptation, which both the cryptomycota
, seem to have developed with great efficiency.
As have we. But, it is a success that is utterly un
-human, and based upon the acceptance that the individual, no matter how powerful, how
clever, how beautiful or rich, or pious, is nothing, because, none of that can, ultimately, save you. Pretty much what Jesus was saying all along.
And Mohammed. And every other faith to have sprung forth from Abraham, who may, very well have been the first to realise it.
In the near future we can expect to be able to observe at least two significant, but very different, comets. Comet 45P/Honda-Mrkos-Pajduskova, a
Short Period comet, who’s orbit will pass close enough to Earth to be observed sometime in August and again in February next year. At just 1.6
kilometres across this relatively small object, and frequent visitor, is under the watchful eye of the Goldstone Deep Space Network.  C 2010X1,
or comet Elenin, as it has become more popularly known as, is a Long Period comet, and most probably originates from the outer Oort cloud. At roughly
4 kilometres across, it should produce a significant tail when it comes under the influence of the Sun. It’s orbit is less clearly understood,
but it is theorised that it last passed by around 11,600 years ago, coincidently enough, around the time of the onset of the Younger Dryas period. It
is possible that our planet will pass through the tail of Elenin, and that this may result in meteor falls, though hopefully none that are large
enough to cause major damage. However, in the unlikely event that a more significant impact should occur, rest assured that it is not the end of the
world, just a change, and that normal service will most likely resume after a few months of cold and darkness.
There is very little we can reasonable do to prevent such a disaster, however, should a comet start heading straight for the planet we can all take a
lesson from our small mammalian ancestors, and dig. But most importantly, don’t forget, that it will only be the end of the world as we know
. The god Osiris, in who’s name NASA has christianed this new mission, may be more readily associated with death and the afterlife, but he
also represented the cycles of nature, where death is celebrated because of the new life that is brings forth. The Earth, if not us, has survived
much, much worse, and subsequently prospered.
Keep calm and carry on, and this too shall pass.
One way or another.
edit on 18-6-2011 by KilgoreTrout because: (no reason given)