Did Lightning and Volcanoes Spark Life on Earth?

[/caption]

Maybe the fictional Dr. Frankenstein wasn’t so crazy after all. Two scientists have resurrected an old experiment, breathing life into a “dead” notion about how life began on our planet. New analysis shows that lightning and gases from volcanic eruptions could have given rise to the first life on Earth.

“It’s alive!”…


Back in the early 1950s, two chemists Stanley Miller and Harold Urey of the University of Chicago did an experiment that tried to recreate the conditions of a young Earth to see how the building blocks of life could have arisen. They used a closed loop of glass chambers and tubes with water and different mixes of hydrogen, ammonia, and methane; the gases thought to be in Earth’s atmosphere billions of years ago. Then they zapped the mixture with an electrical current, to try and confirm a hypothesis that lightning may have triggered the origin of life. After a few days, the mixture turned brown.
When Miller analyzed the water, he found it contained amino acids, which are the building blocks of proteins — life’s toolkit. The spark provided the energy for the molecules to recombine into amino acids, which rained out into the water. The experiment showed how simple molecules could be assembled into the more complex molecules necessary for life by natural processes, like lightning in Earth’s primordial atmosphere.
The apparatus used for Miller's original experiment. Credit: NASA
But there was a problem. Theoretical models and analyses of ancient rocks eventually convinced scientists that Earth’s earliest atmosphere was not rich in hydrogen, so many researchers thought the experiment wasn’t an accurate re-creation of early Earth. But the experiments performed by Miller and Urey were ground-breaking.

“Historically, you don’t get many experiments that might be more famous than these; they re-defined our thoughts on the origin of life and showed unequivocally that the fundamental building blocks of life could be derived from natural processes,” said Adam Johnson, a graduate student with the NASA Astrobiology Institute team at Indiana University, Bloomington. Johnson is the lead author on a paper that resurrects the old origin-of-life experiments, with some tantalizing new findings.

Miller died in 2007. Two former graduate students of Miller’s –geochemists Jim Cleaves of the Carnegie Institution of Washington (CIW) in Washington, D.C., and Jeffrey Bada of Indiana University, Bloomington–were examining samples left in Miller’s lab. They found the vials of products from the original experiment and decided to take a second look with updated technology. Using extremely sensitive mass spectrometers at NASA’s Goddard Space Flight Center Cleaves, Bada, Johnson and colleagues found traces of 22 amino acids in the experimental residues. That is about double the number originally reported by Miller and Urey and includes all of the 20 amino acids found in living things.

Miller actually ran three slightly different experiments, one of which injected steam into the gas to simulate conditions in the cloud of an erupting volcano. “We found that in comparison to Miller’s classic design everyone is familiar with from textbooks, samples from the volcanic apparatus produced a wider variety of compounds,” said Bada.

This is significant because thinking on the composition of Earth’s early atmosphere has changed. Instead of being heavily laden with hydrogen, methane, and ammonia, many scientists now believe Earth’s ancient atmosphere was mostly carbon dioxide, carbon monoxide, and nitrogen. But volcanoes were active during this time period, and volcanoes produce lightning since collisions between volcanic ash and ice particles generate electric charge. The organic precursors for life could have been produced locally in tidal pools around volcanic islands, even if hydrogen, methane, and ammonia were scarce in the global atmosphere.

So, this breathes life into the notion of lightning jump-starting life on Earth. Although Earth’s primordial atmosphere was not hydrogen-rich, gas clouds from volcanic eruptions did contain the right combination of molecules. Is it possible that volcanoes seeded our planet with life’s ingredients? While no one knows what happened next, the researchers are continuing their experiments in an attempt to determine if volcanoes and lightning are the reasons we’re here.

The paper was published in Science on Oct. 17, 2008

Sources: NASA, ScienceNOW

Meteorites Could Preserve Evidence of Alien Life

[/caption]In an effort to understand how organic chemicals might survive after a period in the vacuum of space and then violent re-entry through the atmosphere, scientists have uncovered some interesting results. Last year, the ESA/Russian Foton-M3 mission was launched to test the effects of microgravity on various biological samples. However, a sample of Orkney rock had a harder journey than most. Attached to the outside of the craft, this sample underwent extreme heating during the descent toward the plains of Kazakhstan. Although most of the sample was vaporized, scientists have unveiled results that the sample still contains very obvious signs that it once harboured life. These exciting results set new limits on how organic chemicals may survive unaltered for long periods in space before plunging through a planetary atmosphere, plus it raises some interesting questions into how future searches for extraterrestrial life may be performed…

The principal mission objective for many planetary missions is the search for extraterrestrial life. Although many of our robotic explorers cannot detect life directly, they are able to carry out a host of mini lab experiments on samples taken from the planets surface. NASA’s Phoenix Mars Mission for example has been tirelessly slaving over its hot oven (a.k.a. the Thermal and Evolved-Gas Analyzer, or TEGA for short), dropping samples of Mars soil into its single-use kilns for the last few months. This effort is to vent any prebiotic chemicals into a gas form so instrumentation can then “sniff” the vapour. Should organic chemicals be found, there will be an improved chance that life may have evolved on the Red Planet’s surface.

But say if there is an easier (and cheaper) way to look for ET? Rather than sending hundreds of millions of dollars-worth of hardware to Mars to look for organic chemicals, why can’t we analyse all the rocky samples littered across the globe that originated from space? After all, we now know that some meteorites originate from Mars itself, surely we can perform a far more detailed analysis on these samples instead of depending on a robot millions of miles away?

The big stumbling block comes if we consider the extreme temperatures meteorites are put under during re-entry into the terrestrial atmosphere. Generally one would expect any evidence for past life (whether that be organic chemicals or fossilized remains) to be blow-torched out of existence by reentry temperatures up to 3,000°F (1,650°C). So, researchers from the University of Aberdeen, Scotland, decided to test a chunk of rock from a Scottish island by subjecting it to several days in space and then seeing if any evidence of life in the rock sample remained intact after the descent.

the Kasahkstan landing site in September 2007 ()
the Kazakhstan landing site of Foton-M3 in September 2007 (R. Demets/F. Brandstatter)

The specially prepared piece of Orkney rock took part in the unmanned Foton M3 mission which aimed to examine the rock’s behaviour when it was exposed to the extreme temperatures involved in it’s re-entry through the Earth’s atmosphere,” Professor John Parnell, lead scientist in the study, said.

The reason why Orkney rock was used is because of the material’s robustness when exposed to extreme heat. After all, meteorites need to be made of tough stuff to make it to the ground. “Three quarters of the rock, which was about the size of a small pork pie, was burnt off in the experiment. However, the quarter which returned to Earth has shown us that if intelligent life were to have come into contact with the rock, it would have provided them with evidence that life exists on another planet.”

Now this is where the implications behind these results become abundantly clear. If this piece of rock was sent out into space, only for it to eventually encounter an alien world with intelligent life on its surface, it is conceivable that the rock would survive reentry, preserving the organic chemicals for further study by extraterrestrials. Of course, the reverse is true. If life existed (or exists) on Mars, perhaps we should take a closer look at those Martian meteorite samples…

In the case of the Orkney sample, it contains the remains of 400 million year-old algae, providing a rich chemical signature that Parnell and his team could detect. “We would be extremely excited if we found similar remains in a meteorite arriving from another world,” he added.

Although this experiment only scratches the surface of how organic chemicals may last, unaltered, in space (after all, should a meteoroid sample float in space for millions of years, could organic chemicals be altered by cosmic rays?), it does help us understand that for lower energy reentries, organic chemicals can indeed survive the burn…

If this is the case, let’s sit back and wait for the next meteorite to land (this sounds like another novel approach for WETI!).

Original source: Physorg.com

Perchlorate on Mars Could be Potential Energy Source for Life; Phoenix Team Fires Back at Allegations

[/caption]
It’s been a busy few days for the Phoenix Mars lander rumour-mill. On Friday, an article was published in Aviation Week reporting an undisclosed source from the NASA team analysing results from the Microscopy, Electrochemistry, and Conductivity Analyzer (MECA) had come forward saying Phoenix scientists were in communication with the White House. Apparently there had been new, “provocative” results to come from the MECA, possibly a bigger discovery than last Thursday’s announcement about the scientific proof of water in the Martian regolith. Naturally, the blogosphere went crazy in response to this news. Yesterday, the Phoenix team issued a press release focussing on conflicting results from the MECA and Thermal and Evolved-Gas Analyzer (TEGA) instruments. A MECA sample was found to contain a toxic substance known as perchlorate, usually an oxidizing by-product from industrial processes here on Earth. However, a recently analysed sample from the TEGA turned up no supporting evidence for perchlorate. The study is ongoing. Today, the Phoenix team organized a press conference to discuss a more positive view on the possible discovery of perchlorate, and fired back at recent allegations that science was being withheld from the public…

The Phoenix mission has had an outstanding record of transparency and communicating its science into the public domain. So, one can understand the frustration mission scientists felt when “outrageous” stories (according to Peter Smith, Phoenix principal investigator) were circulated by Aviation Week alleging secrecy about Phoenix findings, strongly indicating that something huge had been discovered and the White House had to be notified. “We want to set the record straight…we’re not with-holding anything” NASA spokesman Dwayne Brown declared at the special press briefing today. The Phoenix team went on to say that the sketchy details in the Aviation Week article led to the huge amount of “speculation” that was thrown around in follow-up stories.

Indeed, there was a significant finding in the works, but the scientists needed more time to analyse the results before issuing a press release on finding perchlorate in the MECA sample. Although the Aviation Week article did specifically say Phoenix was not capable of discovering life, it didn’t stop a number of reports indicating that life had been discovered on the Red Planet (hence the need to communicate the discovery with the President’s Science Advisor first). These speculative claims reached fever-pitch, prompting Phoenix’s Twitter feed to state “Heard about the recent news reports implying I may have found Martian life. Those reports are incorrect.” The speed at which these rumours spread was startling and probably took NASA completely off-guard. This is probably why the perchlorate discovery was announced before a complete and rigorous study could be carried out.

So is perchlorate the death-nail for the possibility of finding suitable conditions for life to be seeded? According to Phoenix scientists, oxidizing chemicals are not always ‘bad news’ for life. “It does not preclude life on Mars. In fact it is a potential energy source,” said William Boynton of the University of Arizona. Indeed, perchlorates have been found in Chile’s highly arid Atacama Desert, a location often used as an analogue for the Martian landscape. Organics in nitrate deposits associated with perchlorates have been found in these harsh conditions, possibly indicating life may form in similar circumstances on Mars.

Although the Phoenix scientists are fairly upbeat about this new finding, other scientists not associated with the mission are cautious. At first glance, perchlorate “is a reactive compound. It’s not usually considered an ingredient for life,” said Brown University geologist John Mustard. Regardless, we will have to wait until all the results are in, especially from the follow-up TEGA sample. Jumping to conclusions are obviously not very helpful to the Phoenix team currently trying to decipher what they are seeing from experiments being carried out by a robot, 400 million miles away.

Sources: Space.com, Phoenix, Space News Examiner

Life Found a Mile Below Terrestrial Seabed; Implications For Life on Mars

We all know how hard life can be, but spare a thought for the microbes recently discovered 1.6 kilometres (1 mile) below the seabed off the coast of Canada. The living conditions are cramped, the environment is a searing 100°C (212F), and yet these hardy cells appear to be thriving. In the midst of the historic landing of Phoenix in the arctic wastes of Mars yesterday, the interest in finding life on the Red Planet has, yet again, reached fever pitch. Although Phoenix isn’t built to look for life, it is assessing the Martian surface water content for signs that it may (or may have been able to) support life. This new discovery of life so deep below the Earth’s surface may set some new limits on just how extreme life can be on other planets…

Off the Newfoundland coastline, scientists have burrowed far below the seabed. Smashing the previous record for subterranean life, this new discovery has found one of the most basic forms of terrestrial life living a mile deep (the previous record held at 842 meters, or 0.5 miles). As I’m no biologist, I’ll leave it to the Reuters news source to describe as to what was found:

Prokaryotes are microbes lacking nuclei, comprising archaea and some types of bacteria. The lack of cell nuclei distinguishes them from eukayrotes, or all animal and plant life.Reuters

These prokaryote specimens were scooped from sediments dating 111 million years old. At these depths, the sediment is subjected to temperatures from 60-100°C (140-212F), and John Parks, professor at the University of Wales (UK), belives that this type of microbe can live even deeper. He believes more prokaryotes could be discovered up to 4 km (2.5 miles) below the seabed. This leads to the question as to whether life on other planets may not be found on the surface, but deep inside their crust.

If there is a substantial subsurface biosphere on earth there could also be substantial biospheres on other planets. Just taking a scoop from the surface of Mars is not going to tell you whether there is life on Mars or not.” – Prof. John Parks

This obviously relates to the attempts made by previous Mars landers to analyse the surface for extraterrestrial microbes. However, a lot of information can be gained by analysing the surface composition for the materials required by life (as we know it) to survive. The Phoenix lander for instance was not designed for life hunting in mind, but it was designed to analyse the top layer of regolith for water content and evidence that liquid water may have once flowed in recent Mars history. Now we have extended our limit on where life may thrive, missions to Mars will need to burrow deeper into the surface, or we’ll simply have to wait till we can do it ourselves.

It is not clear where these subterranean microbes get their energy from. Sunlight probably isn’t a factor; methane and heat from volcanic vents seem more obvious candidates.

There is a problem associated with finding life this deep. It complicates possible plans to bury carbon dioxide emissions deep underground to slow the effects of climate change. It is a completely untouched ecosystem, dumping our waste could have serious consequences for these colonies of microbes. However, it might take some convincing as the U.N. Climate Panel has announced that carbon dioxide burial may be the key tool in the future to prevent this greenhouse gas from escaping into the atmosphere.

Source: Reuters

Imminent Discovery of Life On Mars?

Do you think there is life on Mars? Do you think Phoenix will find evidence of it? Now there’s a blog that’s trying to collect a snapshot of the opinions of scientists, amateurs, and everyday people. “Imminent Discovery” thinks Phoenix may find simple life. Finding this evidence will definitely become headlines… If it happens. Is it possible it might have originated from earth? Perhaps from space, like the famous Antarctica meteorite which was believed to contain evidence of life transported here from Mars?

According to Richard Trentman, a Minor Planet Coordinator at Powell Observatory, “The idea of life in some form on other planets, I believe is highly probable. I have studied about the extreme places on this planet where life has been found and many are far more extreme than may be found on Mars and other planets or moons in our solar system. I believe that anyone that thinks life cannot be “out there” has their eyes closed and blinders on.”

Over time, many astronomers have spent a lifetime dreaming of life and formations on Mars like the misguided Slipher: “Some form of vegetation exists. …The evidence is in the blue-green areas and the changes in their appearance. Vegetation would present exactly the appearance shown, and nothing we know of but vegetation could. The season change that sweeps over them is metabolic…” And yet others take more pragmatic views like astronaut Pete Conrad who commented on bacteria surviving on retrieved Surveyor III remains: “The most significant thing we ever found on the whole Moon was that little bacteria who came back and lived an nobody ever said (anything) about it.”

What’s your opinion? Help to update the book “Imminent Discovery, NASA’s Phoenix and the Secret of Life on Mars” in a post-discovery edition with some of these inputs. Please feel free to Post Your Thoughts On The Imminent Discovery of Life On Mars. Responses may be anonymous or you may use initials if you prefer. To make it more interesting, there is a random drawing of all individuals who enter comments to give away one copy of the classic 1962 book by Earl Slipher “Mars, the Photographic Story”, and a competition between astronomy clubs. Have fun!

Finding “Tightens the Noose on the Possibility of Life” on Mars

mro.thumbnail.jpg

So far, the Mars Exploration Rover (MER) Mission has turned up very little evidence that there is, or was, life on the Red Planet. Even more bad news is on the way from data sent back from NASA rovers Opportunity and Spirit – it would seem that the planet was “too salty” for even the toughest organisms on Earth to survive. It would appear, from new results presented at the American Association for the Advancement of Science (AAAS) in Boston, that although Mars had abundant supplies of water in the past, its oceans would have been too acidic, with poisonous concentrations of minerals. Even when conditions were best on the surface, the very toughest microbes will have found it difficult…

The NASA MER mission has been a resounding success. Both Opportunity and Sprit have operated on Mars longer than any mission scientist would have dreamed. So far, both rovers have been trundling around on the planet for nearly four years, and have carried out some exciting science, analysing the Martian regolith and rocks, observing atmospherics and geology, not forgetting the spectacular panoramic photography… but they have yet to find any compelling evidence for life. Even after the excitement of Spirits big discovery back in Decemeber, the hunt for Martian life remains inconclusive.

Now, it seems, there’s another blow for life on Mars – it’s too salty. It’s been known for a long time that Mars once had large quantities of water, giving hope that life once thrived on the planet. But these new findings suggest the water may have been too rich in minerals, making it very difficult for life (as we know it) to survive.

It was really salty – in fact, it was salty enough that only a handful of known terrestrial organisms would have a ghost of a chance of surviving there when conditions were at their best.” – Dr Andrew Knoll, a biologist at Harvard University, speaking at the AAAS meeting.

Where Opportunity is right now - in Duck Bay (credit: NASA/JPL)
This news comes from Opportunity, currently working in Duck Bay (an alcove attached to Victoria Crater, pictured left) and these new results come from rock analysis in the region. Although this may be discouraging for scientists trying to find life on Mars, this is by no means the final straw. The Phoenix Mission is currently en-route to Mars and one of its mission objectives is to carry out advanced analysis for Martian life. Phoenix lands on May 25 of this year to hunt for life in the frozen North Pole. Also, the Mars Science Laboratory (MSL) is expected for launch in 2009 and will continue the hunt for organic compounds in the Martian regolith.

Source: BBC

Extremophile Hunt Begins in Antarctica, Implications for Exobiologists

sa_big.thumbnail.jpg

An expedition has set off for Antarctica’s Lake Untersee in the quest to find bacteria living in one of the most extreme environments on Earth. The bacteria-hunting team are looking for a basic lifeform in a highly toxic location. Resembling the chemistry of Mars, moons of Jupiter and Saturn, even comets, the ice-covered lake may hold some clues to how life might survive, thrive even, beyond the “normality” of our planet.

Lake Untersee is a strange place. For starters, it is always covered in ice. Secondly, the water’s pH level is so alkali that it resembles bleach rather than regular lake water. And third, it produces methane on a scale that dwarfs any other source on Earth. In fact, the chemistry of this terrestrial location has been likened to the high alkalinity, high methane environments on Mars, frozen moons and comets in our solar system neighborhood.

We already know that extreme life can thrive in the superheated conditions along volcanic vents in the oceans and they can live quite happily in nuclear reactors. Some bacteria are content to be frozen for over 30,000 years before they are thawed to continue life as if nothing had happened. So the search continues… can life thrive in conditions where the pH (a measure of a substances acidity or alkalinity) is considered to be toxic to life? The head scientist of the Antarctic team, Richard Hoover of NASA’s Marshall Space Flight Center, believes that although we consider life that we know to thrive in the “normal” conditions we know and experience ourselves, this may not be the “norm” for life elsewhere in the cosmos.

One thing we’ve learned in recent years, is that you don’t have to have a ‘Goldilocks’ zone with perfect temperature, a certain pH level, and so forth, for life to thrive.” – Richard Hoover.

The team of US, Russian and Austrian scientists hope to identify additional extreme bacteria to add to their impressive accolade of discoveries. So far, previous teams headed by Hoover have found new species and genera of anaerobic microbial extremophiles in the ice and permafrost of Alaska, Siberia, Patagonia, and Antarctica. Now they hope to find life that is hardy enough to deal not only with the extreme cold of the Antarctic, but also with the “normally” poisonous pH and high methane in Lake Untersee. This will characterize the signature of extreme life, a great help to exobiologists when results come in from future life-hunting missions to Mars and other planetary bodies.

With our research this year, we hope to identify some new limits for life in terms of temperature and pH levels. This will help us decide where to search for life on other planets and how to recognize alien life if we actually find it.” – Hoover.

Source: Physorg.com

Earth, Barely Habitable?

lores.thumbnail.jpg

Our home planet has been often described in glowing, nurturing terms. A cradle for life, right in the goldilocks zone. But our planet is actually right on the edge of habitability. If it were any smaller, and a little less massive, plate tectonics might never have gotten started. It turns out, life needs plate tectonics.

Astronomers at the Harvard-Smithsonian Center for Astrophysics announced their research today at the Winter meeting of the American Astronomical Society. According to the team, plate tectonics only really get going when a planet gathers enough mass. And the Earth has just barely enough mass to enjoy plate tectonics.

“Plate tectonics are essential to life as we know it,” said Diana Valencia of Harvard University. “Our calculations show that bigger is better when it comes to the habitability of rocky planets.”

When a planet reaches a large enough size, huge chunks of the planet’s surface can float atop an ocean of boiling magma. These plates spread apart and crash into one another, lifting up gigantic mountain ranges like the Himalayas.

And without plate tectonics, we wouldn’t be here. The process enables complex chemistry and recycles carbon dioxide, which acts like a blanket to keep the Earth warm and hospitable for life. Carbon dioxide is locked into rocks, and then returned to the atmosphere when the rocks melt. Without this cycle, carbon dioxide would get locked away in rocks forever.

The researchers examined what would happen on different rocky planets. They looked at a range of planets, smaller than our planet, up to the so-called “super-Earths” – planets twice our size with 10 times the mass. Any bigger than that, and you start to get a gas planet.

According to their calculations, the Earth is barely habitable. If you get a planet with more mass, the plate tectonics really get rolling, and the carbon cycle becomes really active. A super-Earth could have globe-spanning rings of fire, bursting with hot springs and geysers. Life would have every opportunity to get started.

Of course, if we tried to visit a super-Earth, we’d find the gravity uncomfortable. We’d experience 3 times the gravity trying to walk around on the surface of the planet. Oh, my back.

But for native life forms, it would be paradise.

Original Source: CfA News Release

Sulphur Spring Harbours Extreme Bacteria

A team of scientists has set out to visit an unusual hot spring on Ellesmere Island near the North Pole. This spring spews out sulphur-rich water that has become an ecosystem for bacteria in an otherwise lifeless ice field. The researchers are hoping to understand the underground structure of the spring, and locate the source of the sulphur. An environment like this could help scientists search for signs of life in other hotspots in the Solar System, such as Mars, Europa, or Enceladus.
Continue reading “Sulphur Spring Harbours Extreme Bacteria”

Ancient Life Survived Snowball Earth

Approximately 2.3 billion years ago, bacterial life had generated enough oxygen to make the air breathable for larger creatures. Unfortunately, this was also a stage when our planet went through one of its “Snowball Earth” phases, when the entire planet was encased in kilometer-thick snow and ice. Scientists have found evidence that multi-celled eukaryotes – our distant ancestors – were thriving on Earth, before and after the big chill. While most of the planet was covered, there were probably pockets that were ice free, where islands of life could survive.
Continue reading “Ancient Life Survived Snowball Earth”