As a Nasa scientist claims he's found extra-terrestrial life on meteorites... Is this proof we're all aliens?
Last updated at 9:29 AM on 11th March 2011
In the beginning, of course, the explanation was God. Then, in the age of science, Charles Darwin came along and speculated that it all began in a ‘warm little pond’. Since then, scientists have placed our origins at the bottom of some prehistoric ocean, deep in a volcanic vent or buried in a pit of clay.
The origin of life on Earth — known as ‘biogenesis’ — remains one of the great unsolved mysteries of science. Although Darwin gave us an excellent account of how the first primitive microbes evolved into the wonderful diversity of plants and animals that comprise the living world today, about how the whole tricky business got started in the first place we remain completely in the dark.
But some scientists maintain that the early Earth was so hostile to life that it must have begun elsewhere.
Far fetched? the latest discovery of apparently alien bacteria fossilised in a meteorite raises the fascinating possibility that we live in a 'Star Trek galaxy of essentially humanoid extra-terrestrials
And if we believe the origin of life may predate the origin of the Earth — and, indeed, may stretch right back to the Universe’s earliest days — then we face the very profound conclusion not only that life is everywhere in the Universe, but also that it is all related.
Just this week an American scientist claimed he had found fossils of what look like primitive bacteria in samples from meteorites — rocks which have fallen to Earth.
Dr Richard Hoover, of Nasa, who
has published his results in the Journal of Cosmology, says he has found
matter in several meteorites that resemble a form of primitive earthly
algae called cyanobacteria.
Specifically, some of the
extra-terrestrial ‘fossils’ look very much like a living earthly bug
called Titanospirillum velox, which is found in muds in the Ebro Delta
This, if true, would be extraordinary; the three
meteorite samples Dr Hoover has studied predate any fossils found on
Earth — indeed they are even older than the crust of our planet, dating
from the time when the planets of our solar system were still coming
together from a cloud of dust and rocks.
If he really has found bacterial fossils more than 4.5 billion years old, we will be forced to conclude that life on Earth really did start elsewhere — and furthermore that life is probably everywhere in the Universe.
Is this what an alien looks like? Nasa scientist Dr Richard Hoover claims this fossilised bacteria from a meteorite is similar to bacteria found on earth
As Dr Hoover’s critics have pointed out, ‘extraordinary claims demand extraordinary evidence’. Many sceptics claim these fossils could be simply earthly contamination.
scientists have claimed to have found alien fossils in meteorites
before — most notably in a 4lb lump of rock blasted off the surface of
Mars millions of years ago, which ended up in Antarctica.
meteorite, named ALH84001, generated headline news in 1996 when Nasa
announced it contained ‘biomorphic’ structures, tubule-like objects that
Since then, debate has raged as to whether
this Martian meteorite really does contain ancient life — or merely
It seems to stretch credulity to claim that life began in space, but proponents of ‘exogenesis’, as the theory is known, point to several facts that support their hypothesis. First, we have no idea how life could have arisen on Earth.
'Extraordinary claims': NASA Astrobiologist Dr. Richard B. Hoover has met scepticism from critics
Moreover, we know our planet was, in its early days, an extraordinarily hostile place, with a seething atmosphere composed of nitrogen, steam and hydrogen and various toxic gases.
Furthermore, the first known fossils on our world date from just a few hundred million years after the newly-formed Earth cooled down sufficiently for any life to be possible. In other words, just as soon as life was feasible, it began.
For many scientists, this suspicious coincidence is evidence it must have arrived from elsewhere.
The idea that life pervades the cosmos is very old — the ancient Greeks coined the term ‘Panspermia’ to describe the idea that the seeds of life are everywhere.
The modern hypothesis states that life, or something like it, arose early on in the evolution of the Universe — long before the Earth formed and perhaps 12 billion years ago — when the Universe’s first generation of stars seeded the cosmos with the complex chemicals that are the building blocks of life.
The theory supposes that primitive life — virus-like organisms or bacteria — is distributed around the cosmos by way of meteorites and comets, dust particles between stars, and lumps of rock blasted off the surface of planets.
When these spores arrive on a suitable planet, they take root and begin the process of evolving into more complex lifeforms.
Until recently a big argument against this idea was the belief that life forms could not possibly survive the rigours of deep space.
It is now known, however, that some bacteria, viruses and even primitive animals such as the tiny insect-like eight-legged tardigrade — an earthly creature which scientists have taken into space — can easily survive, perhaps for millions of years, in the radiation-bathed vacuum of space.
Growing evidence: many scientists support the idea of an extra-terrestrial origin for earthly life.
Furthermore, we now know that thanks to cosmic impacts, bits of rock and dust are routinely blasted off the surface of planets such as Earth and Mars, make their way across the void and land elsewhere. Here, we have one plausible mechanism whereby life may be ‘seeded’ throughout the Universe.
Finally, observation of deep-space gas and dust clouds shows that the Universe is rich with the building blocks of life, complex chemicals such as amino acids and other organic compounds.
So does this prove that life began elsewhere?
The most fervent proponents of the Panspermia hypothesis were Sir Fred Hoyle, a British astrophysicist who died ten years ago, and his colleague Chandra Wickramasinghe.
Both maintained not only did life arise elsewhere, but that it continues to arrive in meteoric dust and that these alien life forms may be responsible for epidemic outbreaks, such as the influenza pandemics we have seen for centuries.
The most remarkable consequence of the Panspermia theory being true would be that alien life, if it exists, could be more like life on Earth than scientific wisdom suggests.
Most ‘astrobiologists’ assume that any aliens, be they microbes or intelligent ETs, would be completely different to earthly life, with a different biochemistry and genetic code. But some scientists, such as the Cambridge palaeontologist Professor Simon Conway Morris, have suggested any aliens might be far more like us than we think.
Real life E.T? Most ‘astrobiologists’ assume that any aliens, be they microbes or intelligent ETs, would be completely different to earthly life, with a different biochemistry and genetic code
The fascinating possibility that we live in a ‘Star Trek’ galaxy full of essentially humanoid extra-terrestrials might not be so far off the mark after all.
Certainly, many scientists support the idea of an extra-terrestrial origin for earthly life. Professor Paul Davies, a British cosmologist at Arizona State University, has suggested life on Earth may have its origins on Mars.
He reasons that four billion years ago Mars was a far more hospitable place for life to evolve than Earth.
Being smaller, Mars cooled more quickly and was hit less often by the massive meteor strikes that made the infant solar system such a hazardous environment for life of any kind.
He says we could all be the descendants of ancient Martian microbes blasted off the Red Planet’s surface by later meteorite bombardments.
Professor Davies certainly does not discount the latest claims: ‘I know Richard Hoover well. He’s been assembling evidence of this nature over many years, and it is very familiar to people working in the field.
‘Dr Hoover is a very careful scientist and I believe he has done these experiments to the highest standards. Nevertheless, his claim is iconoclastic, so needs to be treated with obvious caution.’
The origin of life on Earth is a very deep mystery and many scientists are convinced we need to look outside our own planet for an explanation.
One obvious objection to any form of exogenesis is that we have simply transferred the problem elsewhere — we have still not answered the question of how, when or where life began.
If we really have found conclusive proof of alien microbes in a shard of space rock five billion years old, then we would be forced to conclude that ‘life’ may be as ubiquitous as hydrogen and helium, and that at night we are peering into a cosmos that is, quite literally, hopping with life and life, moreover, as we know it.