Nasa's Lander samples Mars water

Nasa has completed a full panorama of the landing site

Nasa's Phoenix Lander spacecraft has for the first time identified water in a sample of soil collected from the planet's surface.

Scientists will now be able to begin studying the sample to see whether the planet was ever, or is, habitable.

The craft previously had problems transferring samples from its robotic arm to the onboard lab for analysis.

The success and the good condition of the craft mean the mission will be extended until the end of September.

Since it landed on June 25, the Phoenix Lander has been studying the surface of Mars to investigate whether it has ever been capable of supporting life.

It has been studying soil with a chemistry lab, an oven called TEGA [Thermal and Evolved-Gas Analyzer instrument], a microscope, a probe and cameras.

Scientists told a press conference at the University of Arizona in Tucson that the planet had so far "proved itself to be interesting".

William Boynton, lead scientist on the mission, said evidence of water ice had been seen before from the Mars Odyssey orbiter, but that this is the first time Martian water has been "touched and tasted".

Full panorama

Phoenix had collected some ice samples last week but was unable to transfer them from the mechanical scoop to the onboard oven for heating and testing.

A dry soil sample was taken instead but the scientists found some ice had been collected too and tests were being conducted on it.

The scientists said they had yet to find organic materials in the sample and stressed that it would take 3 to 4 weeks for the data to be analysed.

The 90-day extension to the mission means Nasa will be able to dig two new trenches between mountains where ice lasts for longer periods of time giving it different characteristics.

"Phoenix is healthy and the projections for solar power look good," said chief scientist Michael Meyer.

"We want to take full advantage of having this resource in one of the most interesting locations on Mars".

Nasa also announced the completion of a full panoramic image of the arctic landing site in approximate true colour.

The panorama is made up of more than 400 individual images taken over several weeks and stitched together to form a mosaic.

Phoenix carries seven science instruments

Life from Venus blown to Earth?

Temperatures on the surface of Venus can reach 464C (867F)

Life on Venus could be blown to Earth by powerful winds, scientists claim.

Previous research has considered the possibility of micro organisms existing in Venus's atmosphere despite extreme temperatures on its surface.

But two scientists at the Cardiff Centre for Astrobiology say microbes from Venus could actually be blown into the Earth's atmosphere by solar winds.

Their findings follow analysis of data from the European Space Agency's Venus Express probe, launched in 2005.

Prof Chandra Wickramasinghe and Dr Janaki Wickramasinghe claim

Venus's clouds contain chemicals that are consistent with the presence of micro organisms.

VENUS FACTS Distance from Sun: 108,200,000km Diameter: 12,103km Year length: 224.7 Earth days Atmosphere: 96% carbon dioxide, 3% nitrogen Moons: 0 Missions: Between 1961 and 1989 the US and USSR launched more than 30 spacecraft towards Venus Brightness: Venus is the brightest object in the sky apart from the Sun and Moon

They suggest that under certain conditions, these microbes from high in Venus's atmosphere could be blown into the Earth's atmosphere.

This process would only take days or weeks.

But

the Sun, Earth and Venus must be suitably aligned,

which last happened in 2004 and will not happen again until 2012.

Prof Wickramasinghe said: "Venus and Earth have often been referred to as sisters because of their geological similarities.

"Our research proposes that the two sisters may be biologically interconnected as well."

The work has been published online in a new paper in the Astrophysics and Space Science journal.

But Prof Fred Taylor, a planetary scientist at Oxford University, said

he was sceptical about the research.

"The idea of life on Venus, particularly the clouds where the temperature and pressure are similar to the Earth, has been floated around for a while but is not really very likely,"

he said.

He added that it was "most unlikely" anyway that microbes from Venus could be transferred to the Earth's atmosphere by solar winds.

The Venus Express probe, launched in November 2005, is orbiting the planet to study its atmosphere.

Scientists hope to learn how Venus, which is similar to Earth in size, mass and composition, evolved so differently over the last 4.6 billion years.

The mission was the first to be sent to the planet in 15 years.

Ammonia on Mars could mean life

by Dr David Whitehouse, BBC

Reposted from:
http://news.bbc.co.uk/2/hi/science/nature/3896335.stm

Ammonia may have been found in Mars' atmosphere which some scientists say could indicate life on the Red Planet.

Researchers say its spectral signature has been tentatively detected by sensors on board the European Space Agency's orbiting Mars Express craft.

Ammonia survives for only a short time in the Martian atmosphere so if it really does exist it must be getting constantly replenished.

There are two possible sources: either active volcanoes, none of which have been found yet on Mars, or microbes.

Suite of molecules

"Ammonia could be the key to finding life on Mars," one US space agency (Nasa) scientist told BBC News Online.

Spectral evidence for the gas was seen by the Planetary Fourier Spectrometer (PFS) on Mars Express.

Professor Vittorio Formisano, principal investigator for the instrument, is expected to release details of new findings from the PFS at an international conference being held next week in Paris.

The PFS is sensitive to radiation in the spectral region of 1.2-5 microns and 5-50 microns - a region rich with important molecules such as water and carbon dioxide. Ammonia has a spectral line at 10 microns.

Although Mars Express has been in orbit around Mars since December 2003, scientists have so far only analysed a fraction of the data the PFS has produced.

Researchers say this is because they are still coming to terms with the complexities of the PFS as well as coping with some nagging power problems on Mars Express.

So far the PFS has observed a depletion of carbon dioxide and an enrichment of water vapour over some of the large extinct volcanoes on Mars.

But it is the detection of minor compounds, possible in the sensors high-resolution mode, which are causing excitement.

The tentative detection of ammonia comes just a few months after methane was found in the Martian atmosphere. Methane is another gas with a possible biological origin.

Ammonia is not a stable molecule in the Martian atmosphere. If it was not replenished in some way, it would only last a few hours before it vanished.

One possibility the scientists have had to rule out is that the ammonia comes from the air bags of the failed Beagle 2 mission. Analysis has revealed that the suspected ammonia's distribution is not consistent with this explanation.

Life on Mars?

The importance of ammonia is that it is a compound of nitrogen and hydrogen.

Nitrogen is rare in the Martian environment but because no form of terrestrial life can exist without it, the presence of ammonia may indicate that Martian microbial life is hoarding it.

"There are no known ways for ammonia to be present in the Martian atmosphere that do not involve life," the Nasa scientist said.

The twin US rovers that landed on the Red Planet in January will be unable to answer the question of the ammonia's origin as they are designed for geological work.

But future missions could include sensors to analyse the ammonia to determine if it has a biological or volcanic origin. Lava deposited on to the surface, or released underground, could produce the gas.

But, so far, no active volcanic hotspots have been detected on the planet by the many spacecraft currently in orbit.

Researchers Discover Remnant of an Ancient 'RNA World'

by PhysOrg

Thanks to Cyberguy for the link.

http://www.physorg.com/news135522723.html

Researchers Discover Remnant of an Ancient 'RNA World'

(PhysOrg.com) -- Some bacterial cells can swim, morph into new forms and even become dangerously virulent - all without initial involvement of DNA. Yale University researchers describe Friday in the journal Science how bacteria accomplish this amazing feat - and in doing so provide a glimpse of what the earliest forms of life on Earth may have looked like.

To initiate many important functions, bacteria sometimes depend entirely upon ancient forms of RNA, once viewed simply as the chemical intermediary between DNA's instruction manual and the creation of proteins, said Ronald Breaker, the Henry Ford II Professor of Molecular, Cellular and Developmental Biology at Yale and senior author of the study.

Proteins carry out almost all of life's cellular functions today, but many scientists like Breaker believe this was not always the case and have found many examples in which RNA plays a surprisingly large role in regulating cellular activity. The Science study illustrates that - in bacteria, at least - proteins are not always necessary to spur a host of fundamental cellular changes, a process Breaker believes was common on Earth some 4 billion years ago, well before DNA existed.

"How could RNA trigger changes in ancient cells without all the proteins present in modern cells? Well, in this case, no proteins, no problem," said Breaker, who is also a Howard Hughes Medical Institute investigator.

Breaker's lab solved a decades-old mystery by describing how tiny circular RNA molecules called cyclic di-GMP are able to turn genes on and off. This process determines whether the bacterium swims or stays stationary, and whether it remains solitary or joins with other bacteria to form organic masses called biofilms. For example, in Vibrio cholerae, the bacterium that causes cholera, cyclic di-GMP turns off production of a protein the bacterium needs to attach to human intestines.

The tiny RNA molecule, comprised of only two nucleotides, activates a larger RNA structure called a riboswitch. Breaker's lab discovered riboswitches in bacteria six years ago and has since shown that they can regulate a surprising amount of biological activity. Riboswitches, located within single strands of messenger RNA that transmit a copy of DNA's genetic instructions, can independently "decide'' which genes in the cell to activate, an ability once thought to rest exclusively with proteins.

Breaker had chemically created riboswitches in his own lab and - given their efficiency at regulating gene expressions - predicted such RNA structures would be found in nature. Since 2002, almost 20 classes of riboswitches, including the one described in today's paper, have been discovered, mostly hidden in non-gene-coding regions on DNA.

"We predicted that there would be an ancient 'RNA city' out there in the jungle, and we went out and found it,'' Breaker said.

Bacterial use of RNA to trigger major changes without the involvement of proteins resolves one of the questions about the origin of life: If proteins are needed to carry out life's functions and DNA is needed to make proteins, how did DNA arise?

The answer is what Breaker and other researchers call the RNA World. They believe that billions of years ago, single strands of nucleotides that comprise RNA were the first forms of life and carried out some of the complicated cellular functions now done by proteins. The riboswitches are highly conserved in bacteria, illustrating their importance and ancient ancestry, Breaker said.

Understanding how these RNA mechanisms work could lead to medical treatments as well, Breaker noted. For instance, a molecule that mimics cyclic di-GMP could be used to disable or disarm bacterial infections such as cholera, he said.

Provided by Yale University

Water 'widespread' on early Mars

In Mars' Nili Fossae, clays are concentrated on slopes and along canyon walls

Water was once widespread on Mars, data from a Nasa spacecraft shows, raising the prospect that the Red Planet could have supported life.

Researchers found evidence of vast lakes, flowing rivers and deltas on early Mars, all of which were potential habitats for microbes.
They also discovered that wet conditions probably persisted for a long time on the Red Planet.
Details appear in the journals Nature and Nature Geoscience.

It wasn't this hot, boiling cauldron. It was a benign, water-rich environment for a long period of time Jack Mustard, Brown University

One study shows that vast regions of Mars' ancient highlands, which cover about half the planet, contain clay minerals - which can form only in the presence of water.

Volcanic lavas buried the clay-rich regions during subsequent, drier periods of the planet's history, but impact craters later exposed them at thousands of locations across Mars.
The data comes from the CRISM (Compact Reconnaissance Imaging Spectrometer for Mars) instrument on the US space agency's Mars Reconnaissance Orbiter spacecraft.
CRISM works by "reading" over 500 colours in reflected sunlight to detect particular minerals on the Martian surface - including those that formed in the presence of water.
"The big surprise from these new results is how pervasive and long-lasting Mars' water was, and how diverse the wet environments were," said Crism's chief scientist Scott Murchie, from the Johns Hopkins University Applied Physics Laboratory in Maryland.
Cosmic bombardment
The clay minerals, known as phyllosilicates, preserve a record of the interaction of water with rocks dating back to the Noachian period of Martian history, which lasted from about 4.6 billion years ago to 3.8 billion years ago.
This was a time in which the Earth, the Moon and Mars were being pummelled by comets and asteroids.

Rivers once flowed into Mars' Jezero Crater, carrying clay minerals

Rocks of this age have largely been destroyed on Earth by plate tectonics. They are preserved on the Moon, but were never exposed to liquid water. So rocks containing phyllosilicates on Mars preserve a unique record of watery environments in the early Solar System, some of which could have been stable long enough for life to get started.
Importantly, CRISM detected hydrated silicates - so called because they contain water in their crystalline structure - within sediments that had been clearly deposited by water.
The clay minerals were found in fans and deltas within the Holden, Eberswalde and Jezero craters on Mars.
"In most locations the rocks are lightly altered by liquid water, but in a few locations they have been so altered that a great deal of water must have flushed though the rocks and soil," said Jack Mustard, professor of planetary geology at Brown University in Rhode Island.
"This is really exciting because we're finding dozens of sites where future missions can land to understand if Mars was ever habitable and if so, to look for signs of past life."
Deep and cool
The European and US space agencies have targeted several phyllosilicate-rich regions as potential landing sites for their next rover missions to Mars.

MSL LANDING SITE SHORTLIST Nili Fossae Trough - 25km-wide linear trough with exposed clays and volcanic deposits Holden Crater - 150km-wide crater once filled by a lake which experienced a massive flood Mawrth Vallis - Valley with many exposed, clays deposited over a long time Eberswalde Crater - 65km-wide depression once filled with water and featuring an ancient delta Northern Meridiani - Region at equator rich in minerals that typically form in presence of water Miyamoto Crater - Impact depression in Meridiani region with exposed clay minerals

The team also found phyllosilicate deposits in thousands of places in and around craters, including the pointed peaks located at the centres of some impact depressions. This example suggests that water was present 4-5km below the ancient Martian surface, the researchers said.
Crater-causing collisions are thought to have excavated underground minerals that were then exposed on the crater peaks.
"Water must have been creating minerals at depth to get the signatures we see," Professor Mustard explained.
The clay minerals must have been formed at relatively low temperatures.
"What does this mean for habitability? It's very strong," explained Professor Mustard.
"It wasn't this hot, boiling cauldron. It was a benign, water-rich environment for a long period of time."
In a separate study published in the journal Nature Geoscience, a team led by Bethany Ehlmann, from Brown University, analysed sedimentary deposits in two deltas within Mars' Jezero crater - which once hosted a body of water measuring some 40km (25 miles) across.
The deltas suggest a river transported clay minerals into the basin from a watershed.
"Not only was water active in this region to weather the rocks, but there was enough of it to run through the beds, transport the clays and run into the lake and form the delta," said Ms Ehlmann.
She added that the deltas appeared to be excellent candidates for finding stored organic matter, because the clays brought in from the watershed and deposited in the lake would have trapped any organisms, leaving a "cemetery of microbes".
Nasa will send a robotic rover, Mars Science Laboratory (MSL), to the planet in September 2009 to look for signs of past or present life.
The European Space Agency (Esa) also plans to send a rover to investigate Mars' habitability. This mission, called ExoMars, is scheduled to launch in 2013.