ramonmercado
CyberPunk
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- Aug 19, 2003
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- 58,263
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- Eblana
Life From Space? (Panspermia; Lithopanspermia)
- Thread starter rynner2
- Start date
- Joined
- Aug 7, 2001
- Messages
- 54,631
Life can survive in space...
Beer microbes live 553 days outside ISS
By Jonathan Amos, Science correspondent, BBC News
A small English fishing village has produced an out-of-this-world discovery.
Bacteria taken from cliffs at Beer on the South Coast have shown themselves to be hardy space travellers.
The bugs were put on the exterior of the space station to see how they would cope in the hostile conditions that exist above the Earth's atmosphere.
And when scientists inspected the microbes a year and a half later, they found many were still alive.
These survivors are now thriving in a laboratory at the Open University (OU) in Milton Keynes.
The experiment is part of a quest to find microbes that could be useful to future astronauts who venture beyond low-Earth orbit to explore the rest of the Solar System.
OU researcher Dr Karen Olsson-Francis told BBC News: "It has been proposed that bacteria could be used in life-support systems to recycle everything.
"There is also the concept that if we were to develop bases on the Moon or Mars, we could use bacteria for 'bio-mining' - using them to extract important minerals from rocks."
This type of research also plays into the popular theory that micro-organisms can somehow be transported between the planets in rocks - in meteorites - to seed life where it does not yet exist.
The Beer microbes were placed on the European Space Agency's (Esa) Technology Exposure Facility, a collection of experimental boxes at the end of the International Space Station's (ISS) Columbus Laboratory.
The bacteria were sent up still sitting on, and in, small chunks of cliff rock.
They would have been exposed to extreme ultraviolet light, cosmic rays, and dramatic shifts in temperature.
All the water in the limestone would also have boiled away into the vacuum of space.
Quite how they managed to come through their 553-day ordeal is now being investigated.
Bacterial spores have been known to endure several years in orbit but this is the longest any cells of cyanobacteria, or photosynthesising microbes, have been seen to survive in space.
The bugs have been classified simply as OU-20. However, they resemble closely a group of cyanobacteria known as Gloeocapsa.
They have a thick cell wall and this could be part of the reason they survived so long in space.
"Gloeocapsa forms a colony of multiple cells that probably protects cells in the centre to exposure from UV radiation and provides some desiccation resistance as well," explained Professor Charles Cockell, who works with Dr Olsson-Francis in the OU's Planetary and Space Sciences Research Institute.
"The ones we have are related to Antarctic species but they're also generally quite well-known in hot deserts. So, as well as the colony-forming habit, I suspect they've got quite good DNA-repair processes, too."
When the OU team despatched the Beer rock to the station, all it knew was that the cliff material contained communities of different bacteria. The scientists had no idea which, if any, would make it back to the ground alive.
Exposure on the platform therefore worked like a screen, identifying bugs likely to have special properties.
"We could send up the spores of known 'extremophiles' and we can be pretty sure they will survive because we know already they're really resistant," Dr Olsson-Francis told BBC News.
"Whereas in this case, we just used a community to select for these organisms. These are just everyday organisms that live on the coast in Beer in Devon and they can survive in space."
The Beer rock was launched to the ISS in 2008. More cliff material was also put on a much shorter space exposure experiment lasting 10 days the previous year. Called Biopan-6, it was lofted by the Russians.
OU-20 came through that challenge, too.
Biopan-6 was the experiment famously survived by a group of "water bears". These tiny invertebrates hold the record for the longest-lived animals in open space.
http://www.bbc.co.uk/news/science-environment-11039206
Beer microbes live 553 days outside ISS
By Jonathan Amos, Science correspondent, BBC News
A small English fishing village has produced an out-of-this-world discovery.
Bacteria taken from cliffs at Beer on the South Coast have shown themselves to be hardy space travellers.
The bugs were put on the exterior of the space station to see how they would cope in the hostile conditions that exist above the Earth's atmosphere.
And when scientists inspected the microbes a year and a half later, they found many were still alive.
These survivors are now thriving in a laboratory at the Open University (OU) in Milton Keynes.
The experiment is part of a quest to find microbes that could be useful to future astronauts who venture beyond low-Earth orbit to explore the rest of the Solar System.
OU researcher Dr Karen Olsson-Francis told BBC News: "It has been proposed that bacteria could be used in life-support systems to recycle everything.
"There is also the concept that if we were to develop bases on the Moon or Mars, we could use bacteria for 'bio-mining' - using them to extract important minerals from rocks."
This type of research also plays into the popular theory that micro-organisms can somehow be transported between the planets in rocks - in meteorites - to seed life where it does not yet exist.
The Beer microbes were placed on the European Space Agency's (Esa) Technology Exposure Facility, a collection of experimental boxes at the end of the International Space Station's (ISS) Columbus Laboratory.
The bacteria were sent up still sitting on, and in, small chunks of cliff rock.
They would have been exposed to extreme ultraviolet light, cosmic rays, and dramatic shifts in temperature.
All the water in the limestone would also have boiled away into the vacuum of space.
Quite how they managed to come through their 553-day ordeal is now being investigated.
Bacterial spores have been known to endure several years in orbit but this is the longest any cells of cyanobacteria, or photosynthesising microbes, have been seen to survive in space.
The bugs have been classified simply as OU-20. However, they resemble closely a group of cyanobacteria known as Gloeocapsa.
They have a thick cell wall and this could be part of the reason they survived so long in space.
"Gloeocapsa forms a colony of multiple cells that probably protects cells in the centre to exposure from UV radiation and provides some desiccation resistance as well," explained Professor Charles Cockell, who works with Dr Olsson-Francis in the OU's Planetary and Space Sciences Research Institute.
"The ones we have are related to Antarctic species but they're also generally quite well-known in hot deserts. So, as well as the colony-forming habit, I suspect they've got quite good DNA-repair processes, too."
When the OU team despatched the Beer rock to the station, all it knew was that the cliff material contained communities of different bacteria. The scientists had no idea which, if any, would make it back to the ground alive.
Exposure on the platform therefore worked like a screen, identifying bugs likely to have special properties.
"We could send up the spores of known 'extremophiles' and we can be pretty sure they will survive because we know already they're really resistant," Dr Olsson-Francis told BBC News.
"Whereas in this case, we just used a community to select for these organisms. These are just everyday organisms that live on the coast in Beer in Devon and they can survive in space."
The Beer rock was launched to the ISS in 2008. More cliff material was also put on a much shorter space exposure experiment lasting 10 days the previous year. Called Biopan-6, it was lofted by the Russians.
OU-20 came through that challenge, too.
Biopan-6 was the experiment famously survived by a group of "water bears". These tiny invertebrates hold the record for the longest-lived animals in open space.
http://www.bbc.co.uk/news/science-environment-11039206
- Joined
- Aug 7, 2001
- Messages
- 54,631
Mission to search for alien life in outer atmosphere
Life from outer space could be surviving on the outer fringes of the Earth's atmosphere, according to scientists who are to launch a mission to search for bacteria that could be living there.
By Richard Gray, Science Correspondent
Published: 9:00PM BST 02 Oct 2010
In science fiction films the search for aliens involves travelling across the galaxy to planets millions of miles away.
But scientists believe they could be close to discovering alien life forms much closer to home – on the outer fringes of Earth's atmosphere.
British scientists, working with the European Space Agency, will this week launch a balloon carrying instruments to search the stratosphere for bacteria and other microorganisms.
They believe there could be species capable of surviving in the high levels of radiation, extreme cold and near vacuum found on the edge of space.
The organisms could be entirely new to science and may even have been brought here from outer space by hitching a ride on asteroids or comets.
If they succeed, it would be the first time alien life had been captured and would lend substantial weight to theories that all life on Earth was brought here from elsewhere in the galaxy.
They also hope they may find new types of bacteria that have been thrown up into the atmosphere by erupting volcanoes.
Clara Juanes-Vallejo, who is leading the research team at Cranfield University, said: "There are theories that life on Earth came from space, so we need to know that life can survive the conditions of space for this to be true.
"The environment in the stratosphere is very extreme. It can get down to -90 degrees C and is a near vacuum. There is also a lot of harmful radiation as there is not the same level of protection as we get from the atmosphere.
"If we know that life can survive in such an extreme environment, then it could also survive in places like Mars or on asteroids.
"If we find microorganisms up there, there are a number of ways it could have arrived. It could have come from space itself, or it could be from our own volcanoes that have projected material up there."
The £60,000 balloon-borne mission, which has been developed along with electronics firm Alpha Micro, will be sent more than 21 miles into the air above the arctic circle where it will suck the thin air through a series of filters.
These will collect any microorganisms out of the atmosphere before being sealed and returned back to Earth to be analysed.
At that altitude, air pressure is a hundredth of that found on the ground and there are high levels of harmful ultraviolet light, which can kill most forms of life.
But scientists have already found bacteria on Earth which thrives in similar conditions and some species of bacteria can form spores which allows them to survive inhospitable conditions for long periods of time.
Nine years ago scientist from India attempted to discover if life could exist in the stratosphere but their findings were quickly cast into doubt by claims they had failed to ensure the collecting equipment was sterile.
The new mission, called CASS-E has been assembled in a sterile environment normally reserved for missions being sent to other planets such as Mars.
It also has been fitted with special seals to prevent any bacteria from Earth that is being carried on the surface of the instrument getting inside the sterile collection area.
Life is thought to have first emerged on Earth around 3.8 billion years ago but how it started has been a topic of much debate.
Some astrobiologists believe that the seeds for life on Earth actually began elsewhere in the galaxy and microbes were carried here on an icy asteroid or comet that collided with our planet.
Recent research has also suggested that life on Earth could even predate a heavy asteroid bombardment around 3.9 billion years ago by surviving in underground habitats where it was protected from the impacts.
Asteroids still continue to hit the Earth – last year there was an explosion over Indonesia – but are far less regular and most tend to burn up in the atmosphere.
Scientists claim that some could leave life behind in the outer atmosphere before they burn up.
http://www.telegraph.co.uk/science/spac ... phere.html
Life from outer space could be surviving on the outer fringes of the Earth's atmosphere, according to scientists who are to launch a mission to search for bacteria that could be living there.
By Richard Gray, Science Correspondent
Published: 9:00PM BST 02 Oct 2010
In science fiction films the search for aliens involves travelling across the galaxy to planets millions of miles away.
But scientists believe they could be close to discovering alien life forms much closer to home – on the outer fringes of Earth's atmosphere.
British scientists, working with the European Space Agency, will this week launch a balloon carrying instruments to search the stratosphere for bacteria and other microorganisms.
They believe there could be species capable of surviving in the high levels of radiation, extreme cold and near vacuum found on the edge of space.
The organisms could be entirely new to science and may even have been brought here from outer space by hitching a ride on asteroids or comets.
If they succeed, it would be the first time alien life had been captured and would lend substantial weight to theories that all life on Earth was brought here from elsewhere in the galaxy.
They also hope they may find new types of bacteria that have been thrown up into the atmosphere by erupting volcanoes.
Clara Juanes-Vallejo, who is leading the research team at Cranfield University, said: "There are theories that life on Earth came from space, so we need to know that life can survive the conditions of space for this to be true.
"The environment in the stratosphere is very extreme. It can get down to -90 degrees C and is a near vacuum. There is also a lot of harmful radiation as there is not the same level of protection as we get from the atmosphere.
"If we know that life can survive in such an extreme environment, then it could also survive in places like Mars or on asteroids.
"If we find microorganisms up there, there are a number of ways it could have arrived. It could have come from space itself, or it could be from our own volcanoes that have projected material up there."
The £60,000 balloon-borne mission, which has been developed along with electronics firm Alpha Micro, will be sent more than 21 miles into the air above the arctic circle where it will suck the thin air through a series of filters.
These will collect any microorganisms out of the atmosphere before being sealed and returned back to Earth to be analysed.
At that altitude, air pressure is a hundredth of that found on the ground and there are high levels of harmful ultraviolet light, which can kill most forms of life.
But scientists have already found bacteria on Earth which thrives in similar conditions and some species of bacteria can form spores which allows them to survive inhospitable conditions for long periods of time.
Nine years ago scientist from India attempted to discover if life could exist in the stratosphere but their findings were quickly cast into doubt by claims they had failed to ensure the collecting equipment was sterile.
The new mission, called CASS-E has been assembled in a sterile environment normally reserved for missions being sent to other planets such as Mars.
It also has been fitted with special seals to prevent any bacteria from Earth that is being carried on the surface of the instrument getting inside the sterile collection area.
Life is thought to have first emerged on Earth around 3.8 billion years ago but how it started has been a topic of much debate.
Some astrobiologists believe that the seeds for life on Earth actually began elsewhere in the galaxy and microbes were carried here on an icy asteroid or comet that collided with our planet.
Recent research has also suggested that life on Earth could even predate a heavy asteroid bombardment around 3.9 billion years ago by surviving in underground habitats where it was protected from the impacts.
Asteroids still continue to hit the Earth – last year there was an explosion over Indonesia – but are far less regular and most tend to burn up in the atmosphere.
Scientists claim that some could leave life behind in the outer atmosphere before they burn up.
http://www.telegraph.co.uk/science/spac ... phere.html
eburacum
Papo-furado
- Joined
- Aug 26, 2005
- Messages
- 5,816
Ah! That's why they are repeating the experiment, is it? The Indians found microbes in the outer atmosphere, but they were all Earth species. Despite this some scientists tried to say that they were microbes from outer space.
They are searching a region of the universe no more than 60 kilometres away from the most complex, and only, biosphere we know of in the Universe. Why do they think that microbes found there would come from outer space, where the nearest solid surface is at least 380,000 km away? Especially when the species found so far have all been Earth species.
- Joined
- Aug 7, 2001
- Messages
- 54,631
Almost half of all Britons believe in aliens
Nearly half of Britons believe in aliens, research has found.
[video ]
7:30AM GMT 30 Nov 2010
A poll of 2,000 adults concluded that 44 per cent were convinced of the existence of extra-terrestrial life.
Men were more likely to believe with 46 per cent answering the survey saying humans are not alone.
The survey was commissioned by the Royal Society, the country's most prestigious scientific body.
Meanwhile a third of those questioned said we should try and make contact with other life forms co-existing in the universe.
However, there was little agreement when it came to decided what form alien life would take.
Prof Simon Conway Morris, an evolution expert from Cambridge University, said people should "throw away all our preconceptions" about what alien life could be like.
Meanwhile only 28 per cent of people answering the YouGov poll would rule out the existence of alien life altogether.
http://www.telegraph.co.uk/news/newstop ... liens.html
Nearly half of Britons believe in aliens, research has found.
[video ]
7:30AM GMT 30 Nov 2010
A poll of 2,000 adults concluded that 44 per cent were convinced of the existence of extra-terrestrial life.
Men were more likely to believe with 46 per cent answering the survey saying humans are not alone.
The survey was commissioned by the Royal Society, the country's most prestigious scientific body.
Meanwhile a third of those questioned said we should try and make contact with other life forms co-existing in the universe.
However, there was little agreement when it came to decided what form alien life would take.
Prof Simon Conway Morris, an evolution expert from Cambridge University, said people should "throw away all our preconceptions" about what alien life could be like.
Meanwhile only 28 per cent of people answering the YouGov poll would rule out the existence of alien life altogether.
http://www.telegraph.co.uk/news/newstop ... liens.html
DougalLongfoot
Abominable Snowman
- Joined
- Jul 26, 2005
- Messages
- 626
No idea what time that would be GMT
- Joined
- Aug 7, 2001
- Messages
- 54,631
'Life as we don't know it' discovery could prove existence of aliens
NASA has sent the internet into a frenzy after it announced an "astrobiology finding" that could suggest alien life exists – even on earth.
By Richard Alleyne, Science Correspondent 6:00PM GMT 01 Dec 2010 105
The discovery could prove the theory of "shadow" creatures which exist in tandem with our own and in hostile environments previously thought uninhabitable.
The "life as we don't know it" could even survive on hostile planets and develop into intelligent creatures such as humans if and when conditions improve.
In a press conference scheduled for tomorrow evening, researchers will unveil the discovery of a microbe that can live in an environment previously thought too poisonous for any life-form to survive.
The bacteria has been found at the bottom of Mono Lake in California's Yosemite National Park which is rich in arsenic – usually poisonous to life.
Somehow the creature uses the arsenic as a way of surviving and this ability raises the prospect that similar life could exist on other planets, which do not have our benevolent atmosphere.
Dr Lewis Dartnell, an astrobiologist at the Centre for Planetary Sciences in London, said: "If these organisms use arsenic in their metabolism, it demonstrates that there are other forms of life to those we knew of.
"They're aliens, but aliens that share the same home as us."
The space agency will announce the full extent of the findings at a press conference titled “astrobiology finding which will impact the search for evidence of extraterrestrial life”.
They believe the creature proves the existence of a second form of life that exists in tandem and before and after intelligent life blooms on planets across the universe.
It follows a growing belief that alien life far from being rare is actually abundant in the universe just in a form that is not recognisable as life.
At the heart of his theory is that life on earth may have come and gone many times during the planet's existence.
These creatures are the remnants of the previous inhabitants.
Scientists have also estimated that life of some kind exists on hundred billion trillion Earth-like planets in space.
However it is usually just bacteria and intelligent life such as us is fleeting and only exists for a fraction of the time.
A study last month said that the universe is teeming with planets capable of supporting alien life.
After studying stars similar to the Sun, astronomers found that almost one in four could have small, rocky planets just like the earth.
Many of these worlds may occupy the "Goldilocks" zone – the region where conditions are neither too hot, nor too cold, for liquid water and possibly life.
Planets outside our own solar system are too far away and too small to see directly with telescopes.
Instead, astronomers study distant stars for tell-tale 'wobbles' – caused when stars are pulled by a planet's gravity.
In the last decade, nearly 500 planets have been discovered outside the solar system this way.
In September astronomers announced the discovery of the most Earth-like planet ever found – a rocky world three times the size of our own world, orbiting a star 20 light years away.
The planet appears to have an atmosphere, a gravity like our own and could have flowing water on its surface.
The discovery came three years after astronomers found a similar, slightly less habitable planet around the same small red star called Gliese 581 in the constellation of Libra.
The planet, named Gliese g, is 118,000,000,000,000 miles away – so far away that light from its start takes 20 years to reach the earth.
The latest news induced feverish debate as to whether scientists were about to announce that they had discovered life on other worlds.
"Did they find ET?", asked one headline in the U S., while another wrote, "Has Nasa found little green men?"
Speculation mounted around the world about the mystery information and buoyed people who already believe in aliens.
One said on U.S. news website MSNBC, "It's still hard for me to understand why people can't accept that aliens exist ... ET is real".
"Fact is, life is everywhere," another wrote. 'I don't need some BS announcement to know it because I have common sense.'
A newspaper in South Korea proclaimed "Nasa to hold news conference on alien life".
The event will be streamed live on the internet tomorrow evening.
There are also conspiracy theorists who believe the government is involved in a cover-up of some kind.
"It is embarrassing how our country makes it all a secret and hides and controls what we know," one American ranted, insisting aliens do exist and the U.S. knows it.
"The government lies to us all the time."
Others were more light-hearted in their predictions.
"Looks like good old Elvis finally ran out of hiding places!," joked a person on a science blog.
For NASA TV streaming video and downlink information, visit: http://www.nasa.gov/ntv at 6pm.
http://www.telegraph.co.uk/science/spac ... liens.html
NASA has sent the internet into a frenzy after it announced an "astrobiology finding" that could suggest alien life exists – even on earth.
By Richard Alleyne, Science Correspondent 6:00PM GMT 01 Dec 2010 105
The discovery could prove the theory of "shadow" creatures which exist in tandem with our own and in hostile environments previously thought uninhabitable.
The "life as we don't know it" could even survive on hostile planets and develop into intelligent creatures such as humans if and when conditions improve.
In a press conference scheduled for tomorrow evening, researchers will unveil the discovery of a microbe that can live in an environment previously thought too poisonous for any life-form to survive.
The bacteria has been found at the bottom of Mono Lake in California's Yosemite National Park which is rich in arsenic – usually poisonous to life.
Somehow the creature uses the arsenic as a way of surviving and this ability raises the prospect that similar life could exist on other planets, which do not have our benevolent atmosphere.
Dr Lewis Dartnell, an astrobiologist at the Centre for Planetary Sciences in London, said: "If these organisms use arsenic in their metabolism, it demonstrates that there are other forms of life to those we knew of.
"They're aliens, but aliens that share the same home as us."
The space agency will announce the full extent of the findings at a press conference titled “astrobiology finding which will impact the search for evidence of extraterrestrial life”.
They believe the creature proves the existence of a second form of life that exists in tandem and before and after intelligent life blooms on planets across the universe.
It follows a growing belief that alien life far from being rare is actually abundant in the universe just in a form that is not recognisable as life.
At the heart of his theory is that life on earth may have come and gone many times during the planet's existence.
These creatures are the remnants of the previous inhabitants.
Scientists have also estimated that life of some kind exists on hundred billion trillion Earth-like planets in space.
However it is usually just bacteria and intelligent life such as us is fleeting and only exists for a fraction of the time.
A study last month said that the universe is teeming with planets capable of supporting alien life.
After studying stars similar to the Sun, astronomers found that almost one in four could have small, rocky planets just like the earth.
Many of these worlds may occupy the "Goldilocks" zone – the region where conditions are neither too hot, nor too cold, for liquid water and possibly life.
Planets outside our own solar system are too far away and too small to see directly with telescopes.
Instead, astronomers study distant stars for tell-tale 'wobbles' – caused when stars are pulled by a planet's gravity.
In the last decade, nearly 500 planets have been discovered outside the solar system this way.
In September astronomers announced the discovery of the most Earth-like planet ever found – a rocky world three times the size of our own world, orbiting a star 20 light years away.
The planet appears to have an atmosphere, a gravity like our own and could have flowing water on its surface.
The discovery came three years after astronomers found a similar, slightly less habitable planet around the same small red star called Gliese 581 in the constellation of Libra.
The planet, named Gliese g, is 118,000,000,000,000 miles away – so far away that light from its start takes 20 years to reach the earth.
The latest news induced feverish debate as to whether scientists were about to announce that they had discovered life on other worlds.
"Did they find ET?", asked one headline in the U S., while another wrote, "Has Nasa found little green men?"
Speculation mounted around the world about the mystery information and buoyed people who already believe in aliens.
One said on U.S. news website MSNBC, "It's still hard for me to understand why people can't accept that aliens exist ... ET is real".
"Fact is, life is everywhere," another wrote. 'I don't need some BS announcement to know it because I have common sense.'
A newspaper in South Korea proclaimed "Nasa to hold news conference on alien life".
The event will be streamed live on the internet tomorrow evening.
There are also conspiracy theorists who believe the government is involved in a cover-up of some kind.
"It is embarrassing how our country makes it all a secret and hides and controls what we know," one American ranted, insisting aliens do exist and the U.S. knows it.
"The government lies to us all the time."
Others were more light-hearted in their predictions.
"Looks like good old Elvis finally ran out of hiding places!," joked a person on a science blog.
For NASA TV streaming video and downlink information, visit: http://www.nasa.gov/ntv at 6pm.
http://www.telegraph.co.uk/science/spac ... liens.html
Mythopoeika
I am a meat popsicle
- Joined
- Sep 18, 2001
- Messages
- 51,690
- Location
- Inside a starship, watching puny humans from afar
rynner2 said:
Well, NASA does sit on information like this and the Mars Meteorite for a long time before they make an announcement. I guess they just have to be sure.
I remember being told by a workmate about the Mars Meteorite in 1990. This woman's brother worked at NASA, and he told her about this meteorite. My colleague said 'don't forget - you heard it from me first'.
6 years later, in 1996, NASA made an announcement that they may have found life inside the meteorite.
So...it took NASA 6 years to work up to making a public announcement.
- Joined
- Aug 7, 2001
- Messages
- 54,631
Arsenic-loving bacteria may help in hunt for alien life
By Jason Palmer, Science and technology reporter, BBC News
The first organism able to substitute one of the six chemical elements crucial to life has been found.
The bacterium, found in a California lake, uses the usually poisonous element arsenic in place of phosphorus.
The find, described in Science, gives weight to the long-standing idea that life on other planets may have a radically different chemical makeup.
It also has implications for the way life arose on Earth - and how many times it may have done so.
The "extremophile" bacteria were found in a briny lake in eastern California in the US.
While bacteria have been found in inhospitable environments and can consume what other life finds poisonous, this bacterial strain has actually taken arsenic on board in its cellular machinery.
Until now, the idea has been that life on Earth must be composed of at least the six elements carbon, hydrogen, oxygen, nitrogen, sulphur and phosphorus - no example had ever been found that violates this golden rule of biochemistry.
The bacteria were found as part of a hunt for life forms radically different from those we know.
"At the moment we have no idea if life is just a freak, bizarre accident which is confined to Earth or whether it is a natural part of a fundamentally biofriendly universe in which life pops up wherever there are Earth-like conditions," explained Paul Davies, the Arizona State University and Nasa Astrobiology Institute researcher who co-authored the research.
"Although it is fashionable to support the latter view, we have zero evidence in favour of it," he told BBC News.
"If that is the case then life should've started many times on Earth - so perhaps there's a 'shadow biosphere' all around us and we've overlooked it because it doesn't look terribly remarkable."
Proof of that idea could come in the form of organisms on Earth that break the "golden rules" of biochemistry - in effect, finding life that evolved separately from our own lineage.
Study lead author Felisa Wolfe-Simon and her colleagues Professor Davies and Ariel Anbar of Arizona State University initially suggested in a paper an alternative scheme to life as we know it.
Their idea was that there might be life in which the normally poisonous element arsenic (in particular as chemical groups known as arsenates) could work in place of phosphorus and phosphates.
Putting it to the test, the three authors teamed up with a number of collaborators and began to study the bacteria that live in Mono Lake in California, home to arsenic-rich waters.
The researchers began to grow the bacteria in a laboratory on a diet of increasing levels of arsenic, finding to their surprise that the microbes eventually fully took up the element, even incorporating it into the phosphate groups that cling to the bacteria's DNA.
Notably, the research found that the bacteria thrived best in a phosphorus environment.
That probably means that the bacteria, while a striking first for science, are not a sign of a "second genesis" of life on Earth, adapted specifically to work best with arsenic in place of phosphorus.
However, Professor Davies said, the fact that an organism that breaks such a perceived cardinal rule of life makes it is a promising step forward.
"This is just a weird branch on the known tree of life," said Professor Davies. "We're interested ultimately in finding a different tree of life... that will be the thing that will have massive implications in the search for life in the Universe.
"The take-home message is: who knows what else is there? We've only scratched the surface of the microbial realm."
John Elliott, a Leeds Metropolitan University researcher who is a veteran of the UK's search for extraterestrial life, called the find a "major discovery".
"It starts to show life can survive outside the traditional truths and universals that we thought you have to use... this is knocking one brick out of that wall," he said.
"The general consensus is that this really could still be an evolutionary adapatation rather than a second genesis. But it's early days, within about the first year of this project; it's certainly one to think on and keep looking for that second genesis, because you've almost immediately found an example of something that's new."
Simon Conway Morris of the University of Cambridge agreed that, whatever its implications for extraterrestrial life, the find was significant for what we understand about life on Earth.
"The bacteria is effectively painted by the investigators into an 'arsenic corner', so what it certainly shows is the astonishing and perhaps under-appreciated versatility of life," he told BBC News.
"It opens some really exciting prospects as to both un-appreciated metabolic versatility... and prompting the questions as to the possible element inventory of remote Earth-like planets".
http://www.bbc.co.uk/news/science-environment-11886943
By Jason Palmer, Science and technology reporter, BBC News
The first organism able to substitute one of the six chemical elements crucial to life has been found.
The bacterium, found in a California lake, uses the usually poisonous element arsenic in place of phosphorus.
The find, described in Science, gives weight to the long-standing idea that life on other planets may have a radically different chemical makeup.
It also has implications for the way life arose on Earth - and how many times it may have done so.
The "extremophile" bacteria were found in a briny lake in eastern California in the US.
While bacteria have been found in inhospitable environments and can consume what other life finds poisonous, this bacterial strain has actually taken arsenic on board in its cellular machinery.
Until now, the idea has been that life on Earth must be composed of at least the six elements carbon, hydrogen, oxygen, nitrogen, sulphur and phosphorus - no example had ever been found that violates this golden rule of biochemistry.
The bacteria were found as part of a hunt for life forms radically different from those we know.
"At the moment we have no idea if life is just a freak, bizarre accident which is confined to Earth or whether it is a natural part of a fundamentally biofriendly universe in which life pops up wherever there are Earth-like conditions," explained Paul Davies, the Arizona State University and Nasa Astrobiology Institute researcher who co-authored the research.
"Although it is fashionable to support the latter view, we have zero evidence in favour of it," he told BBC News.
"If that is the case then life should've started many times on Earth - so perhaps there's a 'shadow biosphere' all around us and we've overlooked it because it doesn't look terribly remarkable."
Proof of that idea could come in the form of organisms on Earth that break the "golden rules" of biochemistry - in effect, finding life that evolved separately from our own lineage.
Study lead author Felisa Wolfe-Simon and her colleagues Professor Davies and Ariel Anbar of Arizona State University initially suggested in a paper an alternative scheme to life as we know it.
Their idea was that there might be life in which the normally poisonous element arsenic (in particular as chemical groups known as arsenates) could work in place of phosphorus and phosphates.
Putting it to the test, the three authors teamed up with a number of collaborators and began to study the bacteria that live in Mono Lake in California, home to arsenic-rich waters.
The researchers began to grow the bacteria in a laboratory on a diet of increasing levels of arsenic, finding to their surprise that the microbes eventually fully took up the element, even incorporating it into the phosphate groups that cling to the bacteria's DNA.
Notably, the research found that the bacteria thrived best in a phosphorus environment.
That probably means that the bacteria, while a striking first for science, are not a sign of a "second genesis" of life on Earth, adapted specifically to work best with arsenic in place of phosphorus.
However, Professor Davies said, the fact that an organism that breaks such a perceived cardinal rule of life makes it is a promising step forward.
"This is just a weird branch on the known tree of life," said Professor Davies. "We're interested ultimately in finding a different tree of life... that will be the thing that will have massive implications in the search for life in the Universe.
"The take-home message is: who knows what else is there? We've only scratched the surface of the microbial realm."
John Elliott, a Leeds Metropolitan University researcher who is a veteran of the UK's search for extraterestrial life, called the find a "major discovery".
"It starts to show life can survive outside the traditional truths and universals that we thought you have to use... this is knocking one brick out of that wall," he said.
"The general consensus is that this really could still be an evolutionary adapatation rather than a second genesis. But it's early days, within about the first year of this project; it's certainly one to think on and keep looking for that second genesis, because you've almost immediately found an example of something that's new."
Simon Conway Morris of the University of Cambridge agreed that, whatever its implications for extraterrestrial life, the find was significant for what we understand about life on Earth.
"The bacteria is effectively painted by the investigators into an 'arsenic corner', so what it certainly shows is the astonishing and perhaps under-appreciated versatility of life," he told BBC News.
"It opens some really exciting prospects as to both un-appreciated metabolic versatility... and prompting the questions as to the possible element inventory of remote Earth-like planets".
http://www.bbc.co.uk/news/science-environment-11886943
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It's life, but not as the scientists of Nasa know it
By Steve Connor, Science Editor
Wednesday, 5 January 2011
It was one of Nasa's most intriguing messages: an invitation to a briefing where it would "discuss an astrobiology finding that will impact the search for extraterrestrial life". The event held on 2 December at Nasa's headquarters in Washington led to headlines around the world, including The Independent's "Science grapples with the concept that alien life may be among us".
However, a growing body of dissent in the scientific blogosphere has cast serious doubts on the findings and called into question the ponderous nature of the classic peer-review system on which science is based.
The findings emerged after researchers funded by Nasa discovered a unique form of life in the shape of a bacterium that could apparently use an arsenic-based compound as a vital building block of its DNA – the first organism on Earth capable of living off arsenic.
The bacterium, known as GFAJ-1, was discovered in Mono Lake in California, which has naturally high levels of arsenic. When the scientists fed the bacteria in the lab on a diet rich in arsenate, which is chemically similar to phosphate, they found that it could incorporate the compound into the structural "backbone" of its DNA.
The lead scientist, Felisa Wolfe-Simon of the Nasa Astrobiology Institute and the US Geological Survey, said that the discovery of an organism on Earth that does something so radically different to all other known forms of life opens the door to what is possible for life elsewhere in the Universe.
In other words, the concept of what is required for life to exist was suddenly changed. Some scientists even suggested that perhaps GFAJ-1 is evidence that alien lifeforms carried to Earth on meteorites may be living among us undetected because until now we have not been looking for them in the right places.
The study, published in the peer-reviewed journal Science, appeared to tick all the requisite boxes in terms of scientific validity. But within days of the findings being published, other experts in the field of astrobiology and microbiology began to punch holes in the work, publishing their doubts in their blogs. The first serious critique came from Rosie Redfield, a microbiologist a the University of British Columbia in Canada, who said that if a PhD student had come to her with these results they would have been sent straight back to the lab bench.
Dr Redfield was one of many who began to think that Nasa had made the same mistake it made in 1996, when it prematurely announced that it had discovered signs of fossilised life in a Martian meteorite called ALH8400, which had fallen to Earth in 1984.
"Nasa's shameful analysis of the alleged bacteria in the Mars meteorite made me very suspicious of their microbiology, an attitude that's only strengthened by my reading of this paper. Basically, it doesn't present any convincing evidence that arsenic has been incorporated into DNA (or any other biological molecule)," Dr Redfield said.
Other scientific bloggers waded in, suggesting that Nasa and Science had not done enough cross-checking. One suggestion was that the findings were the result of a contamination, with arsenic compounds sticking to the bacterium's DNA rather like mud to a shoe.
Alex Bradley, a microbiologist at Harvard University, even suggested that the Nasa-funded scientists had unwittingly demonstrated a flaw in their own research because in their study they had dipped the bacterial DNA into water and because all arsenic compounds fall apart quickly in water this would have resulted in a lot of fragmented genes, which was not the case.
Nature, a rival publication to Science, waded into the debate claiming that the same Nasa scientists who had previously been happy to promote their findings had now retreated "behind the walls of peer review".
"You may have seen claims scientists at Nasa have discovered a bacterium that can replace the phosphorus in its DNA with arsenic. You may have heard that this could help the hunt for aliens. You may even have heard that 'arsenic bacterium' is itself an alien," sniffed Nature. "What you have not seen or heard is a detailed response from Nasa and the scientists involved to online criticism of their work. In the face of worldwide attention on their paper, which Nasa and the team deliberately courted, the researchers have stuck their head in the digital sand."
It was after this scathing editorial in Nature, which said that it strongly encouraged online discussions of peer-reviewed work, that Dr Wolfe-Simon finally posted a response to some of her critics. But now this response has since been criticised by her opponents.
http://www.independent.co.uk/news/scien ... 76116.html
By Steve Connor, Science Editor
Wednesday, 5 January 2011
It was one of Nasa's most intriguing messages: an invitation to a briefing where it would "discuss an astrobiology finding that will impact the search for extraterrestrial life". The event held on 2 December at Nasa's headquarters in Washington led to headlines around the world, including The Independent's "Science grapples with the concept that alien life may be among us".
However, a growing body of dissent in the scientific blogosphere has cast serious doubts on the findings and called into question the ponderous nature of the classic peer-review system on which science is based.
The findings emerged after researchers funded by Nasa discovered a unique form of life in the shape of a bacterium that could apparently use an arsenic-based compound as a vital building block of its DNA – the first organism on Earth capable of living off arsenic.
The bacterium, known as GFAJ-1, was discovered in Mono Lake in California, which has naturally high levels of arsenic. When the scientists fed the bacteria in the lab on a diet rich in arsenate, which is chemically similar to phosphate, they found that it could incorporate the compound into the structural "backbone" of its DNA.
The lead scientist, Felisa Wolfe-Simon of the Nasa Astrobiology Institute and the US Geological Survey, said that the discovery of an organism on Earth that does something so radically different to all other known forms of life opens the door to what is possible for life elsewhere in the Universe.
In other words, the concept of what is required for life to exist was suddenly changed. Some scientists even suggested that perhaps GFAJ-1 is evidence that alien lifeforms carried to Earth on meteorites may be living among us undetected because until now we have not been looking for them in the right places.
The study, published in the peer-reviewed journal Science, appeared to tick all the requisite boxes in terms of scientific validity. But within days of the findings being published, other experts in the field of astrobiology and microbiology began to punch holes in the work, publishing their doubts in their blogs. The first serious critique came from Rosie Redfield, a microbiologist a the University of British Columbia in Canada, who said that if a PhD student had come to her with these results they would have been sent straight back to the lab bench.
Dr Redfield was one of many who began to think that Nasa had made the same mistake it made in 1996, when it prematurely announced that it had discovered signs of fossilised life in a Martian meteorite called ALH8400, which had fallen to Earth in 1984.
"Nasa's shameful analysis of the alleged bacteria in the Mars meteorite made me very suspicious of their microbiology, an attitude that's only strengthened by my reading of this paper. Basically, it doesn't present any convincing evidence that arsenic has been incorporated into DNA (or any other biological molecule)," Dr Redfield said.
Other scientific bloggers waded in, suggesting that Nasa and Science had not done enough cross-checking. One suggestion was that the findings were the result of a contamination, with arsenic compounds sticking to the bacterium's DNA rather like mud to a shoe.
Alex Bradley, a microbiologist at Harvard University, even suggested that the Nasa-funded scientists had unwittingly demonstrated a flaw in their own research because in their study they had dipped the bacterial DNA into water and because all arsenic compounds fall apart quickly in water this would have resulted in a lot of fragmented genes, which was not the case.
Nature, a rival publication to Science, waded into the debate claiming that the same Nasa scientists who had previously been happy to promote their findings had now retreated "behind the walls of peer review".
"You may have seen claims scientists at Nasa have discovered a bacterium that can replace the phosphorus in its DNA with arsenic. You may have heard that this could help the hunt for aliens. You may even have heard that 'arsenic bacterium' is itself an alien," sniffed Nature. "What you have not seen or heard is a detailed response from Nasa and the scientists involved to online criticism of their work. In the face of worldwide attention on their paper, which Nasa and the team deliberately courted, the researchers have stuck their head in the digital sand."
It was after this scathing editorial in Nature, which said that it strongly encouraged online discussions of peer-reviewed work, that Dr Wolfe-Simon finally posted a response to some of her critics. But now this response has since been criticised by her opponents.
http://www.independent.co.uk/news/scien ... 76116.html
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'Life chemicals' may have formed around far-flung star
By Jason Palmer, Science and technology reporter, BBC News
There is now even more evidence that life on Earth may have been seeded by material from asteroids or comets.
Prior research has shown how amino acids - the building blocks of life - could form elsewhere in the cosmos.
These molecules can form in two versions, but life on Earth exclusively uses just one of them.
Now an Astrophysical Journal Letters paper shows how conditions around a far-flung star could favour the formation of one type over another.
Amino acids are corkscrew-shaped molecules that can form twisted to the left or right, and chemistry does not inherently favour one corkscrew direction over another. But without exception, life on Earth makes use of the left-handed version.
A famous experiment in 1952 showed how a spark across a soup of simple chemicals representing the primordial Earth could form amino acids - but like many that followed, it formed equal numbers of left- and right-handed types.
The idea that amino acids might have been delivered to the early Earth by meteorites - themselves formed from asteroids or comets - provided another route, and studies of meteorites have even shown excesses of left-handed amino acids.
Last week, Nasa astrobiologist Daniel Glavin and his colleagues followed up on that finding, saying their research showed that a wide variety of meteor types might play host to excesses of this sort.
What remained was to determine the mechanism by which the left-handed version could be preferentially produced in the cosmos, to be picked up and ultimately delivered to Earth.
Now, Uwe Meierhenrich of University of Nice Sophia Antipolis and colleagues have found one way that this "symmetry breaking" may happen.
They started with chunks of icy material that included several simple molecules: water, methanol, and ammonia - ingredients from which amino acids can be made.
They then exposed the ices to ultraviolet light of a very particular type.
Light has a polarisation, which is to say that light rays oscillate along a given direction - say, up and down, or left and right. While we can't see this effect directly, it is apparent in polarising sunglasses, which block reflected light that tends to be polarised along the left-and-right direction.
The light used by the researchers, by contrast, was what is known as circularly polarised. Rather than along a single direction, the polarisation traces out a corkscrew shape.
Light in the regions around a forming star is known to become circularly polarised like this as it passes through vast clouds of dust grains that are aligned by magnetic fields.
The experiments showed that the circularly polarised light led to the formation of both left- and right-handed amino acids - but there were slightly over a percent more of the left-handed version.
That is the level of excess that Dr Glavin and his colleagues have found in meteorites found on Earth - and the mechanism is a compelling fact in the case for an extraterrestrial origin for Earth's first amino acids.
"This excess is pretty cool," Dr Glavin told BBC News.
"You've got to break the symmetry somehow, this is critical. But how do you break it? That's one of the most important questions: did life just randomly choose one type over another? It's starting to look like Nature helped a bit."
However, Dr Glavin noted that these molecules can swap their forms, and that an unequal mixture of the two types will settle out to an equal mixture in time, a process called racemisation.
"These are exactly the kinds of experiments we need to be doing but we do need to keep the big picture in mind," he said.
That is, he said, to further shore up the idea that life on Earth started with a delivery of extraterrestrial ingredients, it still remains to pin down the mechanism by which the unequal mixtures can be preserved for the long journey from far-flung stars.
http://www.bbc.co.uk/news/science-environment-12240549
By Jason Palmer, Science and technology reporter, BBC News
There is now even more evidence that life on Earth may have been seeded by material from asteroids or comets.
Prior research has shown how amino acids - the building blocks of life - could form elsewhere in the cosmos.
These molecules can form in two versions, but life on Earth exclusively uses just one of them.
Now an Astrophysical Journal Letters paper shows how conditions around a far-flung star could favour the formation of one type over another.
Amino acids are corkscrew-shaped molecules that can form twisted to the left or right, and chemistry does not inherently favour one corkscrew direction over another. But without exception, life on Earth makes use of the left-handed version.
A famous experiment in 1952 showed how a spark across a soup of simple chemicals representing the primordial Earth could form amino acids - but like many that followed, it formed equal numbers of left- and right-handed types.
The idea that amino acids might have been delivered to the early Earth by meteorites - themselves formed from asteroids or comets - provided another route, and studies of meteorites have even shown excesses of left-handed amino acids.
Last week, Nasa astrobiologist Daniel Glavin and his colleagues followed up on that finding, saying their research showed that a wide variety of meteor types might play host to excesses of this sort.
What remained was to determine the mechanism by which the left-handed version could be preferentially produced in the cosmos, to be picked up and ultimately delivered to Earth.
Now, Uwe Meierhenrich of University of Nice Sophia Antipolis and colleagues have found one way that this "symmetry breaking" may happen.
They started with chunks of icy material that included several simple molecules: water, methanol, and ammonia - ingredients from which amino acids can be made.
They then exposed the ices to ultraviolet light of a very particular type.
Light has a polarisation, which is to say that light rays oscillate along a given direction - say, up and down, or left and right. While we can't see this effect directly, it is apparent in polarising sunglasses, which block reflected light that tends to be polarised along the left-and-right direction.
The light used by the researchers, by contrast, was what is known as circularly polarised. Rather than along a single direction, the polarisation traces out a corkscrew shape.
Light in the regions around a forming star is known to become circularly polarised like this as it passes through vast clouds of dust grains that are aligned by magnetic fields.
The experiments showed that the circularly polarised light led to the formation of both left- and right-handed amino acids - but there were slightly over a percent more of the left-handed version.
That is the level of excess that Dr Glavin and his colleagues have found in meteorites found on Earth - and the mechanism is a compelling fact in the case for an extraterrestrial origin for Earth's first amino acids.
"This excess is pretty cool," Dr Glavin told BBC News.
"You've got to break the symmetry somehow, this is critical. But how do you break it? That's one of the most important questions: did life just randomly choose one type over another? It's starting to look like Nature helped a bit."
However, Dr Glavin noted that these molecules can swap their forms, and that an unequal mixture of the two types will settle out to an equal mixture in time, a process called racemisation.
"These are exactly the kinds of experiments we need to be doing but we do need to keep the big picture in mind," he said.
That is, he said, to further shore up the idea that life on Earth started with a delivery of extraterrestrial ingredients, it still remains to pin down the mechanism by which the unequal mixtures can be preserved for the long journey from far-flung stars.
http://www.bbc.co.uk/news/science-environment-12240549
eburacum
Papo-furado
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There are still lots of questions to answer here. Why would circularly polarised light result in a non-racemic mixture? So far they only have an experimental result, not a mechanism, as far as I can tell.
Why don't the compounds become racemic afterwards because of racemisation?
The end result of this polarisation process is a mixture that is only 1% enriched with left-handed molecules. What causes this 1% to become exclusive? I suspect that it may be just chance, and other worlds may evolve right-handed biospheres, but slightly less often. But we won't know until we get there.
Why don't the compounds become racemic afterwards because of racemisation?
The end result of this polarisation process is a mixture that is only 1% enriched with left-handed molecules. What causes this 1% to become exclusive? I suspect that it may be just chance, and other worlds may evolve right-handed biospheres, but slightly less often. But we won't know until we get there.
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Meteorites 'could have carried nitrogen to Earth'
By Neil Bowdler, Science reporter, BBC News
A meteorite found in Antarctica could lend weight to the argument that life on Earth might have been kick-started from space, scientists are claiming.
Chemical analysis of the meteorite shows it to be rich in the gas ammonia.
It contains the element nitrogen, found in the proteins and DNA that form the basis of life as we know it.
The researchers say meteorites like this could have showered the early Earth, providing the missing ingredients for life.
Details of the study by researchers at Arizona State University and the University of California, Santa Cruz, are published in the journal Proceedings of the National Academy of Sciences.
The new study is based on analysis of just under 4g of powder extracted from a meteorite called Grave Nunataks 95229 (named after its place of discovery in Antarctica), discovered in 1995.
On treatment, the powder sample was shown to contain abundant amounts of ammonia as well as hydrocarbons.
Professor Sandra Pizzarello, who led the research, says the study "shows that there are asteroids out there that when fragmented and become meteorites, could have showered the Earth with an attractive mix of components, including a large amount of ammonia".
Meteorites like this could have supplied the early Earth with enough nitrogen in the right form for primitive life forms to emerge, she says.
Previous studies have focused on the "Murchison" meteorite, which hit Australia in 1969, which was found to be rich in organic compounds.
The professor says Murchison is "too much of a good thing" and contains hydrocarbon molecules which you would expect to find at the end rather than the start of the life story.
She believes the composition of these compounds are too complex and too random in their molecular shape to have played a role in life on Earth.
The theory that our planet may have been seeded by a comet or asteroid arises partly from the belief the formative Earth might not have been able to provide the full inventory of simple molecules needed for the processes which led to primitive life.
The suggestions is that the Asteroid Belt, between Mars and Jupiter, away from the heat and pressure of the forming planets, could have been a better place for such processes.
Collisions between asteroids within the belt produce meteoroids which shoot off around the Solar System and which can carry materials to the Earth.
Dr Caroline Smith, a meteorite expert at London's Natural History Museum agrees the important element in the new study is the nitrogen, even though she would like to see similar results repeated in other meteorites.
"One of the problems with early biology on the early Earth is you need abundant nitrogen for all these prebiological processes to happen - and of course nitrogen is in ammonia.
"A lot of the evidence shows that ammonia was not present in much abundance in the early Earth, so where did it come from?"
What specifically caused life to begin on Earth remains a mystery. Professor Pizzarello hypothesises material from a meteorite may have interacted with environments on Earth such as volcanoes or tidal pools, but says all remains a matter of guess work.
"You find these extraterrestrial materials (in meteorites) which have what you need," she says, "but on the how and when, in which environments and by what means - really, we don't know."
"You can only say that yes, it seems that the extraterrestrial environments could have had the good stuff."
http://www.bbc.co.uk/news/science-environment-12597564
By Neil Bowdler, Science reporter, BBC News
A meteorite found in Antarctica could lend weight to the argument that life on Earth might have been kick-started from space, scientists are claiming.
Chemical analysis of the meteorite shows it to be rich in the gas ammonia.
It contains the element nitrogen, found in the proteins and DNA that form the basis of life as we know it.
The researchers say meteorites like this could have showered the early Earth, providing the missing ingredients for life.
Details of the study by researchers at Arizona State University and the University of California, Santa Cruz, are published in the journal Proceedings of the National Academy of Sciences.
The new study is based on analysis of just under 4g of powder extracted from a meteorite called Grave Nunataks 95229 (named after its place of discovery in Antarctica), discovered in 1995.
On treatment, the powder sample was shown to contain abundant amounts of ammonia as well as hydrocarbons.
Professor Sandra Pizzarello, who led the research, says the study "shows that there are asteroids out there that when fragmented and become meteorites, could have showered the Earth with an attractive mix of components, including a large amount of ammonia".
Meteorites like this could have supplied the early Earth with enough nitrogen in the right form for primitive life forms to emerge, she says.
Previous studies have focused on the "Murchison" meteorite, which hit Australia in 1969, which was found to be rich in organic compounds.
The professor says Murchison is "too much of a good thing" and contains hydrocarbon molecules which you would expect to find at the end rather than the start of the life story.
She believes the composition of these compounds are too complex and too random in their molecular shape to have played a role in life on Earth.
The theory that our planet may have been seeded by a comet or asteroid arises partly from the belief the formative Earth might not have been able to provide the full inventory of simple molecules needed for the processes which led to primitive life.
The suggestions is that the Asteroid Belt, between Mars and Jupiter, away from the heat and pressure of the forming planets, could have been a better place for such processes.
Collisions between asteroids within the belt produce meteoroids which shoot off around the Solar System and which can carry materials to the Earth.
Dr Caroline Smith, a meteorite expert at London's Natural History Museum agrees the important element in the new study is the nitrogen, even though she would like to see similar results repeated in other meteorites.
"One of the problems with early biology on the early Earth is you need abundant nitrogen for all these prebiological processes to happen - and of course nitrogen is in ammonia.
"A lot of the evidence shows that ammonia was not present in much abundance in the early Earth, so where did it come from?"
What specifically caused life to begin on Earth remains a mystery. Professor Pizzarello hypothesises material from a meteorite may have interacted with environments on Earth such as volcanoes or tidal pools, but says all remains a matter of guess work.
"You find these extraterrestrial materials (in meteorites) which have what you need," she says, "but on the how and when, in which environments and by what means - really, we don't know."
"You can only say that yes, it seems that the extraterrestrial environments could have had the good stuff."
http://www.bbc.co.uk/news/science-environment-12597564
James_H
And I like to roam the land
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- Messages
- 7,629
Has Alien Life Been Found? [on a meteorite]
This is a meteorite coming from a comet, and if this is found to be true, would greatly support the panspermia theory.
The meteorite itself fell in 1864, and has itself been the subject of previous (spurious) claims of life in the past.[/url]
This is a meteorite coming from a comet, and if this is found to be true, would greatly support the panspermia theory.
The meteorite itself fell in 1864, and has itself been the subject of previous (spurious) claims of life in the past.[/url]
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Dr. Hoover's paper can be accessed directly at:
http://journalofcosmology.com/Life100.html
It seems to me the debate is only beginning. However, I suspect the key issues of contention will be whether the microbes (or microbe-like forms, take your pick ...) necessarily arrived with the meteorites from elsewhere (other than earth), and secondly whether the meteorites themselves were clearly not of earthly origin.
We have meteorites that were believed to have been cast off Mars (presumably by a large impact event). Earth has had large impact events as well, so it's conceivable the meteorites might represent terrestrial ejecta that eventually fell back to earth. I suspect ruling out this possibility will be a major point of contention as the debate unfolds.
http://journalofcosmology.com/Life100.html
It seems to me the debate is only beginning. However, I suspect the key issues of contention will be whether the microbes (or microbe-like forms, take your pick ...) necessarily arrived with the meteorites from elsewhere (other than earth), and secondly whether the meteorites themselves were clearly not of earthly origin.
We have meteorites that were believed to have been cast off Mars (presumably by a large impact event). Earth has had large impact events as well, so it's conceivable the meteorites might represent terrestrial ejecta that eventually fell back to earth. I suspect ruling out this possibility will be a major point of contention as the debate unfolds.
eburacum
Papo-furado
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Some skeptical articles about Hoovers apparent discovery here
http://rrresearch.blogspot.com/2011/03/ ... orite.html
http://rrresearch.blogspot.com/2011/03/ ... orite.html
http://blogs.discovermagazine.com/badas ... meteorite/
http://cosmiclog.msnbc.msn.com/_news/20 ... irs-debate
This claim appears to be somewhat controversial, to say the least.
eburacum
Papo-furado
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That remains to be seen. The Journal of Cosmology is a peculiar institution, and has a somewhat different standard for accepting papers to other bodies. Hoover's paper was already rejected by the International Journal of Astrobiology before being accepted by the JoC.
See
http://www.spaceref.com/news/viewpr.html?pid=32928
as for the JoC, see
http://scienceblogs.com/pharyngula/2011 ... bacter.php
See
http://www.spaceref.com/news/viewpr.html?pid=32928
as for the JoC, see
http://scienceblogs.com/pharyngula/2011 ... bacter.php
- Joined
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- 54,631
A not-so-brief history of the search for life on Mars:
http://www.guardian.co.uk/science/2011/ ... ears-space
It includes these thoughts:
"Consider the two competing scenarios. First, probes discover lifeforms that have a different genetic code from the DNA that is commonplace in life on Earth. That would indicate that Martian life had a very different evolutionary history from ours and would tell us that on two sister planets, in one humble corner of the galaxy, life appeared independently and separately, a fact that would suggest the appearance of life in general is a common affair on worlds elsewhere in the galaxy.
Even more intriguing, however, is the alternative scenario: those samples could be found to have organisms that use DNA, as Earthly life does, as their genetic code. It is extremely unlikely that such a highly specialised, complex molecule like DNA could have evolved separately on the two planets, indicating that there must be a common origin for Martian and Earthly life. And given that it is far easier for rocks carrying cells or bacteria to escape Mars's relatively low gravitational field compared with Earth's relatively powerful gravity, we would face an intriguing prospect. Life based on DNA first appeared on Mars and then spread to Earth, where it then evolved into the myriad forms of plants and creatures that exist today. If this was found to be the case, we would have to face the logical conclusion: we are all Martians." 8)
http://www.guardian.co.uk/science/2011/ ... ears-space
It includes these thoughts:
"Consider the two competing scenarios. First, probes discover lifeforms that have a different genetic code from the DNA that is commonplace in life on Earth. That would indicate that Martian life had a very different evolutionary history from ours and would tell us that on two sister planets, in one humble corner of the galaxy, life appeared independently and separately, a fact that would suggest the appearance of life in general is a common affair on worlds elsewhere in the galaxy.
Even more intriguing, however, is the alternative scenario: those samples could be found to have organisms that use DNA, as Earthly life does, as their genetic code. It is extremely unlikely that such a highly specialised, complex molecule like DNA could have evolved separately on the two planets, indicating that there must be a common origin for Martian and Earthly life. And given that it is far easier for rocks carrying cells or bacteria to escape Mars's relatively low gravitational field compared with Earth's relatively powerful gravity, we would face an intriguing prospect. Life based on DNA first appeared on Mars and then spread to Earth, where it then evolved into the myriad forms of plants and creatures that exist today. If this was found to be the case, we would have to face the logical conclusion: we are all Martians." 8)
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Mars: Nasa images show signs of flowing water
By Hamish Pritchard, Science Reporter
[video: Scientists see dark 'tendrils', signs of flowing water, emerge from rocky Martian outcrops]
Striking new images from the mountains of Mars may be the best evidence yet of flowing, liquid water, an essential ingredient for life.
The findings, reported today in the journal Science, come from a joint US-Swiss study.
A sequence of images from the Mars Reconnaissance Orbiter show many long, dark "tendrils" a few metres wide.
They emerge between rocky outcrops and flow hundreds of metres down steep slopes towards the plains below.
They appear on hillsides warmed by the summer sun, flow around obstacles and sometimes split or merge, but when winter returns, the tendrils fade away.
This suggests that they are made of thawing mud, say the researchers.
"It's hard to imagine they are formed by anything other than fluid seeping down slopes," said Mars Reconnaissance Orbiter Project Scientist Richard Zurek of Nasa's Jet Propulsion Laboratory, but they appear when it's still too cold for fresh water.
"The best explanation we have for these observations so far is flow of briny water, although this study does not prove that," said planetary geologist and lead author Professor Alfred McEwen of the Lunar and Planetary Laboratory, University of Arizona.
Saltiness lowers the temperature at which water freezes, and water about as salty as Earth's oceans could exist at these sites in summer.
"This could be the first flowing water," said Professor McEwen. This has profound implications in the search for extraterrestrial life.
"Liquid water is absolutely essential for life, and we've found life on Earth in pretty much every moist niche," said Dr Lewis Dartnell, astrobiologist at University College London, who was not involved in the study.
"So perhaps there could be hardy microbes surviving in these short periods of summer meltwater on the desert surface of Mars."
This was echoed by an expert on life in extreme environments, Professor Shiladitya DasSarma of the University of Maryland, also not involved in this study: "Their results are consistent with the presence of large and extensive underground salty lakes on Mars."
"This is an exciting possibility for those of us studying salt-loving (halophilic) micro-organisms here on Earth, since it opens the possibility that these kinds of hearty bugs may also inhabit our neighbouring planet," he said.
"Halophilic microbes are champions at withstanding the most punishing conditions, complete desiccation and ionising (space) radiation."
For geologist Joe Levy of Portland State University, a specialist in Antarctic desert ecosystems, who did not contribute to this work, they represent "a truly tantalising astrobiological target".
These small and mysterious tendrils could then be the best place to look for Martian life. Professor McEwen says that "for present-day life, these are the most accessible sites".
http://www.bbc.co.uk/news/science-environment-14408928
By Hamish Pritchard, Science Reporter
[video: Scientists see dark 'tendrils', signs of flowing water, emerge from rocky Martian outcrops]
Striking new images from the mountains of Mars may be the best evidence yet of flowing, liquid water, an essential ingredient for life.
The findings, reported today in the journal Science, come from a joint US-Swiss study.
A sequence of images from the Mars Reconnaissance Orbiter show many long, dark "tendrils" a few metres wide.
They emerge between rocky outcrops and flow hundreds of metres down steep slopes towards the plains below.
They appear on hillsides warmed by the summer sun, flow around obstacles and sometimes split or merge, but when winter returns, the tendrils fade away.
This suggests that they are made of thawing mud, say the researchers.
"It's hard to imagine they are formed by anything other than fluid seeping down slopes," said Mars Reconnaissance Orbiter Project Scientist Richard Zurek of Nasa's Jet Propulsion Laboratory, but they appear when it's still too cold for fresh water.
"The best explanation we have for these observations so far is flow of briny water, although this study does not prove that," said planetary geologist and lead author Professor Alfred McEwen of the Lunar and Planetary Laboratory, University of Arizona.
Saltiness lowers the temperature at which water freezes, and water about as salty as Earth's oceans could exist at these sites in summer.
"This could be the first flowing water," said Professor McEwen. This has profound implications in the search for extraterrestrial life.
"Liquid water is absolutely essential for life, and we've found life on Earth in pretty much every moist niche," said Dr Lewis Dartnell, astrobiologist at University College London, who was not involved in the study.
"So perhaps there could be hardy microbes surviving in these short periods of summer meltwater on the desert surface of Mars."
This was echoed by an expert on life in extreme environments, Professor Shiladitya DasSarma of the University of Maryland, also not involved in this study: "Their results are consistent with the presence of large and extensive underground salty lakes on Mars."
"This is an exciting possibility for those of us studying salt-loving (halophilic) micro-organisms here on Earth, since it opens the possibility that these kinds of hearty bugs may also inhabit our neighbouring planet," he said.
"Halophilic microbes are champions at withstanding the most punishing conditions, complete desiccation and ionising (space) radiation."
For geologist Joe Levy of Portland State University, a specialist in Antarctic desert ecosystems, who did not contribute to this work, they represent "a truly tantalising astrobiological target".
These small and mysterious tendrils could then be the best place to look for Martian life. Professor McEwen says that "for present-day life, these are the most accessible sites".
http://www.bbc.co.uk/news/science-environment-14408928
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It seems that even Smithsonian fans are getting fed-up with SETI and its 40 odd years of inactivity?
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You can't accuse SETI of inactivity. They've been very active, even if they haven't produced the results they hoped for.Ghostisfort said:
But many people (including SETI) have been saying for a long time that a search for radio signals is far too narrow and limited. Most of the ideas on the Smithsonian list have been discussed for years - you may find mentions of them on this very thread.
(I know I have posted about searching for laser signals, eg (2002)
http://www.forteantimes.com/forum/viewt ... 497#146497
and (2005)
http://www.forteantimes.com/forum/viewt ... 922#493922 )
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I think my own feelings on SETI can be summed-up with reference to the Drake Equation:
N = R* x fp x ne x fl x fi x fc x L - very impressive and scientific sounding, but totally meaningless, with not one single variable that anyone can put a number to.
Why would an advanced civilisation want to signal to us?
What could they possibly have to say that would not put them in danger of being attacked by American guns?
The problem, as usual, is academia and its assumption that an alien scientific community would be just like themselves with a large proportion engaged in weapons research.
An advanced civilisation would have to do certain things to become an advanced civilisation.
The first would be guaranteed care for every individual human being, something requiring a modification to profiteering.
A commitment to true free will.
An abundant clean energy supply for all, something that academic science has no interest in.
This would all have to be administered by a world government, something no one is interested in under present circumstances.
Climate control to ensure food for all.
There is quite a list of requirements before our entrance into a galactic community would be considered.
N = R* x fp x ne x fl x fi x fc x L - very impressive and scientific sounding, but totally meaningless, with not one single variable that anyone can put a number to.
Why would an advanced civilisation want to signal to us?
What could they possibly have to say that would not put them in danger of being attacked by American guns?
The problem, as usual, is academia and its assumption that an alien scientific community would be just like themselves with a large proportion engaged in weapons research.
An advanced civilisation would have to do certain things to become an advanced civilisation.
The first would be guaranteed care for every individual human being, something requiring a modification to profiteering.
A commitment to true free will.
An abundant clean energy supply for all, something that academic science has no interest in.
This would all have to be administered by a world government, something no one is interested in under present circumstances.
Climate control to ensure food for all.
There is quite a list of requirements before our entrance into a galactic community would be considered.
kamalktk
Antediluvian
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Surely they are nice, but why are these necessary? Do you subscribe to the "violent civilizations will blow themselves up first" school of thought? Some rather brutish cultures (both internally and towards other cultures) have made some large technological strides historically, in fact pretty much all history is rather brutish.Ghostisfort said:
Mythopoeika
I am a meat popsicle
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Ghostisfort said:
Really? What about all the billions that are being poured into fusion energy research?
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We've done that one.Mythopoeika said:
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kamalktk said:
The brutish civilisation is us and we don't need to blow ourselves up. The spiralling cost of energy leading to food shortages will do the job.
This is not about the emotion of being nice, it's about survival.