By Richard Gray for MailOnline

Support grows for the panspermia theory that claims life on Earth may have arrived here from outer space

Panspermia is a theory that life was carried to Earth by comets or meteors
The idea has remained on the fringe of mainstream science for decades
Recent findings has seen it gathering more support among astrobiologists
They say there is a good chance life first evolved on Mars instead of Earth

The birth of life on Earth is one of the greatest puzzles to have faced scientists, but some are starting to question whether it was even born here at all.

Astrobiologists are collecting growing evidence that suggests life may have begun elsewhere in the galaxy and was carried here by meteorites or comets around 3.8 to 4 billion years ago – a theory known as panspermia.

For example organic molecules and water have been found on comets racing through our solar system, suggesting the materials needed to kickstart life on Earth came from space.

However, there are some who go further and say life itself formed elsewhere and was carried here where it found the conditions were perfect to evolve.

Salt flat indicates some of the last vestiges of surface water on Mars, CU-Boulder study finds – Mars turned cold and dry long ago, but researchers at the University of Colorado Boulder have discovered evidence of an ancient lake that likely represents some of the last potentially habitable surface water ever to exist on the Red Planet. The study, published Thursday in the journal Geology, examined an 18-square-mile chloride salt deposit (roughly the size of the city of Boulder) in the planet?s Meridiani region near the Mars Opportunity rover?s landing site. As seen on Earth in locations such as Utah?s Bonneville Salt Flats, large-scale salt deposits are considered to be evidence of evaporated bodies of water. Digital terrain mapping and mineralogical analysis of the features surrounding the deposit indicate that this one-time lakebed is no older than 3.6 billion years old, well after the time period when Mars is thought to have been warm enough to sustain large amounts of surface Is this where life finally died out on Mars? Salt flats…

Panspermia is not a new thoery – it was first proposed in 1871 – but it has more recently gathered fresh support as astronomers have discovered just how full the universe is with organic compounds.

THE PANSPERMIA HYPOTHESIS

Panspermia is a theory that suggests life spreads across the known physical universe, hitchhiking on comets or meteorites.

For example, life such as extremophiles, capable of surviving the inhospitable conditions of space, could become trapped in debris that is ejected into space after collisions between asteroids and planets that harbour life.

These life-forms may travel dormant for an extended amount of time before colliding randomly with other planets.

The idea of directed panspermia, however, suggests lifeforms are deliberately sent out through the universe by intelligent civilizations

Professor Francis Crick, one of the biologists who discovered the structure of DNA, examined the possibility of this in a paper in 1973.

However, Professor Crick and his colleagues concluded that the scientific evidence was ‘inadequate at the present time to say anything about the probability’.

Although no evidence to prove this has yet been found, the idea of panspermia, which remains on the fringe of mainstream science, is not considered as far-fetched as it once was, according toNew Scientist.

Peter Ward, a biologist at the University of Washington in Seattle, told the magazine: ‘I think the case for Mars as the origin of Earth life is pretty good.’

He added that should proof be found that life on Earth is extraterrestrial in origin, it would have some pretty major impacts on current scientific and religious thinking.

He said: ‘It’s a big blow. For some religious fundamentalists, it is an axiom that there is but one life and it is here on Earth.’

Many scientists have pointed at the apparent suddenness of life appearing on Earth around 3.8 billion years ago at the same time conditions to support life became perfect.

Some scientists go further and say the entire Milky Way may be teeming with life.

Professor Chandra Wickramasinghe, an astrobiologist at the University of Buckingham and long time supporter of panspermia, believes Earth is constantly exchanging organic and even living material with planets around neighbouring star systems.

He was recently involved in the publication of several papers that found what he believes to be fossilised remains of organisms in meteorites and tiny algae-like organisms living high up in the Earth’s atmosphere that have been carried here by passing comets.

Speaking to New Scientist, Professor Wickramasinghe said: ‘this was conjecture in the past, purely theoretical, but now we have evidence for it. It’s changing slowly, but surely.’

COULD WE SOON SPOT PLANT LIFE ON OTHER PLANETS?

Forget little green men, the first alien life we spot could be green plants.

The light coming from distant solar systems could reveal the existence of plants growing on other planets, according to astronomers.

Scientists have found that the pigments in the leaves of plants and other photosynthetic organisms reflect coloured light in peculiar ways, producing a distinctive fingerprint.

This means it may be possible to filter out other light coming from distant stars to reveal only light that has been reflected by living plants on a planet’s surface.

The findings could provide a new way of finding alien life beyond our solar system that does not rely upon detecting radio signals from other intelligent life forms.

Instead, astrobiologists may be able to pinpoint planets orbiting other stars where photosynthetic organisms exist by looking for coloured visible light that has been polarised in specific ways.

This could also help to identify planets which may be habitable by humans – photosynthesis produces oxygen as a key by product.

In a paper published earlier this year in the Journal of Astrobiology, which Professor Wickramasinghe edits, he and his colleagues outlined how they think life may have arrived here on Earth.

They wrote: ‘Recent studies have led to detections of some 900 exoplanets in a nearby small sample volume of our galaxy.

‘Extrapolations from this study give an estimate of 140 billion habitable planetary systems in our galaxy alone, most of these being associated with faint red dwarf stars.

‘On such a basis the mean distance between life-friendly planetary systems is only a few light years.

‘This relatively short interplanetary distance is easily bridged by escaping dust, debris, meteorites and comets.

‘Material expelled at speeds greater than the escape speed from a planetary system like our own solar system will, in general, have hyperbolic orbits with respect to a nearby star, so the probability of direct capture will in general be very low.

‘However, sub-micron dust including bacteria and viruses released by transiting cometary bolides, even if they are in hyperbolic orbits, will be easily be stopped by friction (gas drag) in the interplanetary disc of the recipient planetary system, and thus serve to infect habitable planets.’

Put more simply, organisms and molecules on comets travelling past planets could be deposited on that planet.

Most recently, they found a strange tiny titanium metal orb about the same width of a human hair surrounded by an organic goo in their samples.

They have also studied meteorite material that contains structures which have been interpreted by some as fossilised microorganisms.

However, the idea is also gathering some supporters from the more mainstream side of science.

Only a few decades ago scientists considered the idea of alien life unlikely, but now Nasa scientists believe it is only a matter of time before evidence of life is discovered elsewhere in our solar system.

The US space agency is focusing on searching for signs of life on Mars while the European Space Agency is looking to the moon.

It is planning a robotic mission to drill beneath the surface of the Moon to look for meteorites that may provide clues to how life started on Earth and if it was carried here from elsewhere.

Scientists at Nasa have also conducted experiments using simulated meterorites fired into space and allowed to reenter the atmosphere.

These have shown DNA and some bacterial spores can survive the extreme heat and pressures of entering the Earth’s atmosphere.

This has lent support for some of the fundamental ideas underpinning panspermia.

Several leading scientists including Professor Stephen Hawking and the Astronomer Royal Martin Rees last month backed a new $100 million bid to hunt for alien life.

IMAGES:
Life on Earth began around 3.8 billion years ago but it may not have originated on our planet. There is growing support for a fringe theory of panspermia that suggests life first started elsewhere in space and was carried here by comets and meteorites, as illustrated above, that bombarded our planet during its early history
The Rosetta mission to comet 67P/Churyumov-Gerasimenko (pictured) has found organic molecules on its surface and even led to claims that it may even be home to microbial life. Some astrobiologists believe comets like this may carry biological material freely around the galaxy and seeded life on Earth
Professor Wickramasignhe and his colleague Dr Milton Wainwright point to the remains of apparent microorganisms collected 16 miles (26km) up in the stratosphere by a high altitude balloon during the Perseid meteor shower in 2013.
Professor Wickramasignhe and his colleague Dr Milton Wainwright have found several mysterious particles, like the ‘ghost particle’ above, in samples taken from high up in the Earth’s atmosphere they controversially claim provides evidence that passing meteors shower the Earth with dust laden with biological material
This sphere is another of the materials collected by Dr Wainwright and his colleagues (above), which they claim could be the remains of a colony of microorganisms
Astrobiologists have used high altitude balloons to take samples in the stratosphere during the Perseid meteor shows in 2013, like the one shown above. They say there is growing evidence from these samples that life originally arrived on Earth from other planets and that it continues to do so

For more on this story go to: http://www.dailymail.co.uk/sciencetech/article-3193585/Are-ALIENS-Growing-support-panspermia-theory-life-Earth-carried-outer-space.html#ixzz3jkWeBxpP
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