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How life might evolve with “exotic” biochemistry and solvents

September 19, 2009 By admin Leave a Comment

London, September 18 (ANI): Scientists at a new interdisciplinary research group in Austria are working to uncover how life might evolve with “exotic” biochemistry and solvents, such as sulfuric acid instead of water.

The research group for Alternative Solvents as a Basis for Life Supporting Zones in (Exo-) Planetary Systems was established by the University of Vienna.

Traditionally, planets that might sustain life are looked for in the ‘habitable zone’, the region around a star in which Earth-like planets with carbon dioxide, water vapor and nitrogen atmospheres could maintain liquid water on their surfaces.

Consequently, scientists have been looking for biomarkers produced by extraterrestrial life with metabolisms resembling the terrestrial ones, where water is used as a solvent and the building blocks of life, amino acids, are based on carbon and oxygen.

However, these may not be the only conditions under which life could evolve.

“It is time to make a radical change in our present geocentric mindset for life as we know it on Earth,” said scientist Johannes Leitner.

“Even though this is the only kind of life we know, it cannot be ruled out that life forms have evolved somewhere that neither rely on water nor on a carbon and oxygen based metabolism,” he added.

One requirement for a life-supporting solvent is that it remains liquid over a large temperature range.

Water is liquid between 0 degree Celsius and 100 degrees C, but other solvents exist which are liquid over more than 200 degrees C.

Such a solvent would allow an ocean on a planet closer to the central star.

The reverse scenario is also possible. A liquid ocean of ammonia could exist much further from a star.

Furthermore, sulfuric acid can be found within the cloud layers of Venus and it is now known that lakes of methane/ethane cover parts of the surface of the Saturnian satellite Titan.

Consequently, the discussion on potential life and the best strategies for its detection is ongoing and not only limited to exoplanets and habitable zones.

The newly established research group at the University of Vienna, together with international collaborators, will investigate the properties of a range of solvents other than water, including their abundance in space, thermal and biochemical characteristics as well as their ability to support the origin and evolution of life supporting metabolisms. (ANI)

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Space telescopes may soon start detecting air-breathing aliens in exoplanets

May 18, 2009 By admin Leave a Comment

London, May 18 (ANI): The day is not far when it would be possible to see signs of life on planets far away from our own solar system-thanks to space telescopes that could soon be able to detect “biosignatures” in the light from planets orbiting other stars.

Talking at an astrobiology meeting, scientists revealed that it could be possible to get clues of life on such exoplanets via tiny fraction of the parent star’s light that interacts with the planet on its journey towards Earth.

Already, the Hubble and Spitzer space telescopes have detected gases such as carbon dioxide and water vapour in the atmospheres of a handful of gas-giant exoplanets while they pass in front of their parent stars.

But these instruments are not sensitive enough to detect evidence of life – so-called biosignatures – in the spectrum of rocky Earth-like planets.

One of the most important biosignature is oxygen and it was announced that NASA’s infrared James Webb Space Telescope (JWST) could distinguish signs of oxygen present in the atmospheres of Earth-like planets around the nearest stars.

Another promising device is NASA’s proposed Terrestrial Planet Finder, which could launch in the 2020s and would be powerful enough to spot oxygen-rich planets in systems much farther from Earth (even when they are not passing in front of their parent stars) by seeing light reflected from the planet’s surface.

However, oxygen alone does not prove that life is present, especially on a planet close to its parent star.

Another possible biosignature might be found in the light reflected off living matter like cyanobacteria, reports New Scientist magazine.

The red and blue light reflected from an alien world could be used to create maps of its oceans, which could at least indicate the planet is habitable.

In an experiment led by Nicholas Cowan of the University of Washington in Seattle, researchers made maps by using the measurements by NASA’s Deep Impact spacecraft, which showed Earth’s apparent colour varying over time.

When more water is on the side facing the probe, the planet appears bluer, while a large landmass looks redder-which helped the researchers to construct a crude map of how land and water are distributed on our planet.

The researchers said that a telescope like NASA’s proposed Terrestrial Planet Finder could do the same for Earth-like exoplanets.

The findings were presented at a symposium on the search for life beyond Earth held last week in Baltimore, Maryland. (ANI)

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‘Astro-comb’ to hunt for Earth-like planets

May 8, 2009 By admin Leave a Comment

Washington, May 8 (ANI): Researchers at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, have created an “astro-comb” to help astronomers detect lighter planets, more like Earth, around distant stars.

In most cases, extrasolar planets can’t be seen directly-the glare of the nearby star is too great-but their influence can be discerned through spectroscopy, which analyzes the energy spectrum of the light coming from the star.

Not only does spectroscopy reveal the identity of the atoms in the star (each element emits light at a certain characteristic frequency), it can also tell researchers how fast the star is moving away or toward Earth, courtesy of the Doppler effect, which occurs whenever a source of waves is itself in motion.

By recording the change in the frequency of the waves coming from or bouncing off of an object, scientists can deduce the velocity of the object.

Though the planet might weigh millions of times less than the star, the star will be jerked around a tiny amount owing to the gravity interaction between star and planet.

This jerking motion causes the star to move toward or away from Earth slightly in a way that depends on the planet’s mass and its nearness to the star.

The better the spectroscopy used in this whole process, the better will be the identification of the planet in the first place and the better will be the determination of planetary properties.

In tests, the Harvard researchers are now able to calculate star velocity shifts of less than 1 m/sec, allowing them to more accurately pinpoint the planet’s location.

Smithsonian researcher David Phillips says that he and his colleagues expect to reach a velocity resolution of 60 cm/sec, and maybe even 1 cm/sec, which when applied to the activities of large telescopes presently under construction, would open new possibilities in astronomy and astrophysics, including simpler detection of more Earth-like planets.

With this new approach, Harvard astronomers achieve their great improvement using a frequency comb as the basis for the astro-comb.

A special laser system is used to emit light not at a single energy but a series of energies (or frequencies), evenly spaced across a wide range of values.

A plot of these narrowly-confined energy components would look like the teeth of a comb, hence the name frequency comb.

The energy of these comb-like laser pulses is known so well that they can be used to calibrate the energy of light coming in from the distant star.

The resultant astro-comb should enable a further expansion of extrasolar planetary detection. (ANI)

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World’s biggest telescope will search heavens for planets

April 5, 2009 By admin Leave a Comment

London, Apr 5 (ANI): Scientists are planning to build a giant telescope that will be powerful enough to identify habitable planets like Earth in distant solar systems.

Astronomers claim the European Extremely Large Telescope, which will house a mirror the width of five double decker buses placed end to end, will be the first optical telescope capable of picking out the weak pinpricks of light that are reflected from planets as they orbit stars.

The scientific breakthrough will be able to spot rocky Earth-like planets up to 100 million million miles away, reports The Telegraph.

Light’s telltale signatures coming from such planets could also reveal whether there is water on their surfaces, which gases are in their atmospheres, and even if they may harbour life itself.

The 1 billion euro E-ELT will have more mirror glass than all the other telescopes in the world put together.

It is expected to be so powerful that if astronomers were to use it to peer at the Moon, they would be able to see the car sized lunar rover that was left on the moon by astronauts during the Apollo missions.

Isobel Hook, joint chair of the E-ELT science working group and an astronomer at Oxford University, said: “The astronomy community has been moving towards building progressively bigger telescopes to get sharper images.

“The resolution of the ELT is going to allow us to see objects and structures in the universe that we have been blind to until know.” (ANI)

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Virtual maps provide bird’s-eye view of Titan’s Earth-like landscapes

March 25, 2009 By admin Leave a Comment

Washington, March 25 (ANI): Scientists have made new virtual topographic maps of Saturn’s moon Titan, which provide a bird’s-eye view its Earth-like landscapes.

Cassini radar team member Randy Kirk with the Astrogeology Science Center at the U.S. Geological Survey in Flagstaff, Arizona, created the maps.

He used some of the 20 or so areas where two or more overlapping radar measurements were obtained during 19 Titan flybys.

These stereo overlaps cover close to two percent of Titan’s surface.

The process of making topographic maps from them is just beginning, but the results already reveal some of the diversity of Titan’s geologic features.

The new flyover maps show, for the first time, the 3-D topography and height of the 1,200-meter (4,000-foot) mountain tops, the north polar lake country, the vast dunes more than 100 meters (300 feet) high that crisscross the moon, and the thick flows that may have oozed from possible ice volcanoes.

“These flyovers let you take in the bird’s-eye sweeping views of Titan, the next best thing to being there,” said Kirk.

“We’ve mapped many kinds of features, and some of them remind me of Earth. Big seas, small lakes, rivers, dry river channels, mountains and sand dunes with hills poking out of them, lava flows,” he added.

The maps show some features that may be volcanic flows. These flows meander across a shallow basin in the mountains.

One area suspected to be an ice volcano, Ganesa Macula, does not appear to be a volcanic dome. It may still have originated as a volcano, but it’s too soon to know for sure.

“It could be a volcanic feature, a crater, or something else that has just been heavily eroded,” said Kirk.

The stereo coverage includes a large portion of Titan’s north polar lakes of liquid ethane and methane. Based on these topographical models, scientists are better able to determine the depth of lakes.

The highest areas surrounding the lakes are some 1,200 meters (about 4,000 feet) above the shoreline.

By comparing terrain around Earth to the Titan lakes, scientists estimate their depth is likely about 100 meters (300 feet) or less.

More 3-D mapping of these lakes will help refine these depth estimates and determine the volume of liquid hydrocarbons that exist on Titan.

This information is important because these liquids evaporate and create Titan’s atmosphere. Understanding this methane cycle can provide clues to Titan’s weather and climate. (ANI)

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NASA’s Kepler mission blasts off in search of Earth-like planets

March 7, 2009 By admin Leave a Comment

Washington, March 7 (ANI): NASA’s Kepler mission, which would search other Earth-like planets, has been successfully launched into space from Cape Canaveral Air Force Station, Florida, US, aboard a United Launch Alliance Delta II.

Kepler is designed to find the first Earth-size planets orbiting stars at distances where water could pool on the planet’s surface. Liquid water is believed to be essential for the formation of life.

“It was a stunning launch,” said Kepler Project Manager James Fanson of NASA’s Jet Propulsion Laboratory in Pasadena, California.

“Our team is thrilled to be a part of something so meaningful to the human race – Kepler will help us understand if our Earth is unique or if others like it are out there,” he added.

Engineers acquired a signal from Kepler at 12:11 a.m. on March 7th, after it separated from its spent third-stage rocket and entered its final sun-centered orbit, trailing 950 miles behind Earth.

The spacecraft is generating its own power from its solar panels.

“Kepler now has the perfect place to watch more than 100,000 stars for signs of planets,” said William Borucki, the mission’s science principal investigator at NASA’s Ames Research Center at Moffett Field, California.

“Everyone is very excited as our dream becomes a reality. We are on the verge of learning if other Earths are ubiquitous in the galaxy,” he added.

Engineers have begun to check Kepler to ensure it is working properly, a process called “commissioning” that will take about 60 days.

In about a month or less, NASA will send up commands for Kepler to eject its dust cover and make its first measurements.

After another month of calibrating Kepler’s single instrument, a wide-field charge-couple device camera, the telescope will begin to search for planets.

The first planets to roll out on the Kepler “assembly line” are expected to be the portly “hot Jupiters” – gas giants that circle close and fast around their stars.

Neptune-size planets will most likely be found next, followed by rocky ones as small as Earth.

The true Earth analogs – Earth-sized planets orbiting stars like our sun at distances where surface water, and possibly life, could exist – would take at least three years to discover and confirm.

Ground-based telescopes also will contribute to the mission by verifying some of the finds.

In the end, Kepler will give us our first look at the frequency of Earth-size planets in our Milky Way galaxy, as well as the frequency of Earth-size planets that could theoretically be habitable. (ANI)

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NASA’s Kepler mission to search for Earth-sized planets

March 5, 2009 By admin Leave a Comment

London, March 4 (ANI): NASA’s Kepler mission, which is all set to launch on March 6, will take a long look at the stars in the constellation Cygnus, searching for an Earth-sized planet elsewhere in the Galaxy.

According to a report in Nature News, the Kepler space telescope, which is the single instrument on board Kepler, will hunt for Earth-like ‘exoplanets’ – planets beyond the Solar System.

Project scientists expect to find hundreds of such worlds, including perhaps the first exact Earth analogue.

Kepler will detect exoplanets by watching them passing, or ‘transiting’, in front of their star, dimming the starlight temporarily.

It needs to do this at least three times to confirm a planet. If an exoplanet is in an Earth-like orbit, that will take three years.

Of the 342 exoplanets spotted to date, most have been found through the radial velocity method, which picks up slight wobbles in a star’s position caused by the gravitational tug of an orbiting planet.

This method is most likely to find large planets close to their stars, however.

Transits are better suited to finding something more like Earth in size and orbit. So far, 58 transiting planets have been found.

The COROT satellite, launched by the French space agency CNES in 2006, has found seven of those transiting planets, and is in many ways a forerunner to Kepler.

Kepler, however, will orbit the Sun rather than Earth, as COROT does, which means it can spend more time looking at the stars.

Kepler also has a bigger telescope: its mirror is 1.4 metres across, compared with COROT’s 30 centimetres.

Kepler will stare at 100,000 preselected Sun-like stars 180-920 parsecs away, sending data back to Earth every 30 days.

Scientists will scan those data for planets that might be habitable: not too close to their parent star, nor too far away that liquid water won’t exist.

“We all hope this mission will deliver what is promised,” said Giovanna Tinetti, a senior research fellow at University College London.

“If Kepler comes up with empty hands, that will be truly astonishing,” said Alan Boss, an exoplanet theorist from the Carnegie Institution in Washington DC.

According to William Borucki, the project’s principal investigator at NASA’s Ames Research Center in Moffett Field, California, even if Kepler doesn’t identify any Earth-like planets, that would mean our Solar System really is unique. (ANI)

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NASA spacecraft all set to search for Earth-like worlds

February 20, 2009 By admin Leave a Comment

Washington, Feb 20 (ANI): NASA’s Kepler spacecraft is all set to be moved to the launch pad and will soon begin a journey to search for worlds that could potentially host life.

Kepler is scheduled to blast into space from Cape Canaveral Air Force Station, Florida, aboard a Delta II rocket on March 5.

It is the first mission with the ability to find planets like Earth – rocky planets that orbit sun-like stars in a warm zone where liquid water could be maintained on the surface.

Liquid water is believed to be essential for the formation of life.

“Kepler is a critical component in NASA’s broader efforts to ultimately find and study planets where Earth-like conditions may be present,” said Jon Morse, the Astrophysics Division director at NASA Headquarters in Washington.

“The planetary census Kepler takes will be very important for understanding the frequency of Earth-size planets in our galaxy and planning future missions that directly detect and characterize such worlds around nearby stars,” he added.

The mission will spend three-and-a-half years surveying more than 100,000 sun-like stars in the Cygnus-Lyra region of our Milky Way galaxy.

It is expected to find hundreds of planets the size of Earth and larger at various distances from their stars.

If Earth-size planets are common in the habitable zone, Kepler could find dozens; if those planets are rare, Kepler might find none.

In the end, the mission will be humanity’s first step toward answering a question posed by the ancient Greeks: are there other worlds like ours or are we alone?

“Finding that most stars have Earths implies that the conditions that support the development of life could be common throughout our galaxy,” said William Borucki, Kepler’s science principal investigator at NASA’s Ames Research Center at Moffett Field, alifornia.

“Finding few or no Earths indicates that we might be alone,” he added.

The Kepler telescope is specially designed to detect the periodic dimming of stars that planets cause as they pass by. Some star systems are oriented in such a way that their planets cross in front of their stars, as seen from our Earthly point of view.

As the planets pass by, they cause their stars’ light to slightly dim, or wink.

The telescope can detect even the faintest of these winks, registering changes in brightness of only 20 parts per million.

To achieve this resolution, Kepler will use the largest camera ever launched into space, a 95-megapixel array of charged couple devices, known as CCDs. (ANI)

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Astronomers find “Super-Neptune”

January 22, 2009 By Rajesh Leave a Comment

Washington, Jan 22 (ANI): Astronomers at the Harvard-Smithsonian Center for Astrophysics have discovered a planet somewhat larger and more massive than Neptune orbiting a star 120 light-years from Earth, which they have termed as “Super-Neptune”.

While Neptune has a diameter 3.8 times that of Earth and a mass 17 times Earth’s, the new world (named HAT-P-11b) is 4.7 times the size of Earth and has 25 Earth masses.

HAT-P-11b was discovered because it passes directly in front of (transits) its parent star, thereby blocking about 0.4 percent of the star’s light.

This periodic dimming was detected by a network of small, automated telescopes known as “HATNet,” which is operated by the Center in Arizona and Hawaii.

HAT-P-11b is the 11th extrasolar planet found by HATNet, and the smallest yet discovered by any of the several transit search projects underway around the world.

Transit detections are particularly useful because the amount of dimming tells the astronomers how big the planet must be.

By combining transit data with measurements of the star’s “wobble” (radial velocity) made by large telescopes like Keck, astronomers can determine the mass of the planet.

A number of Neptune-like planets have been found recently by radial velocity searches, but HAT-P-11b is only the second Neptune-like planet found to transit its star, thus permitting the precise determination of its mass and radius.

The newfound world orbits very close to its star, revolving once every 4.88 days. As a result, it is baked to a temperature of around 1100 degrees F.

The star itself is about three-fourths the size of our Sun and somewhat cooler.

There are signs of a second planet in the HAT-P-11 system, but more radial velocity data are needed to confirm that and determine its properties.

Another team has located one other transiting super-Neptune, known as GJ436b, around a different star. It was discovered by a radial velocity search and later found to have transits.

According to Harvard astronomer Gaspar Bakos, who led the discovery team, “Having two such objects to compare helps astronomers to test theories of planetary structure and formation.”

HAT-P-11 is in the constellation Cygnus, which puts in it the field of view of NASA’s upcoming Kepler spacecraft.

Kepler will search for extrasolar planets using the same transit technique pioneered by ground-based telescopes.

This mission potentially could detect the first Earth-like world orbiting a distant star. (ANI)

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Asteroid dust in and around dead stars hints at Earth-like planets

January 7, 2009 By Rajiv Gupta Leave a Comment

London, Jan 7 (ANI): Scientists have observed asteroid dust in and around a handful of dead stars, that is made up of similar materials as the Earth, which suggests Earth-like planets may be common in the Universe.

According to a report in New Scientist, six white dwarfs, the burned-out embers of Sun-like stars, showed heavy elements, or metals, in their atmospheres.

That is unusual because white dwarfs contain about as much mass as the Sun squeezed into bodies the size of the Earth, giving them surface gravities 10,000 times stronger than the Sun’s.

That should cause heavy elements to sink towards their centres – and out of sight.

In addition, the six stars also shine more brightly than expected in infrared light, which suggests the stars are surrounded by dust, which glows at infrared wavelengths.

The dusty debris is thought to be the remains of asteroids that once orbited the white dwarfs, but were gravitationally torn apart when they wandered too close to the stars.

Michael Jura of the University of California, Los Angeles, and colleagues measured the infrared light from these stars using NASA’s Spitzer Space Telescope.

The team found the dust contains a glassy silicate material similar to olivine, which is common on Earth and has also been seen on the Moon and Mars.

The dust also seems to have no carbon, consistent with Earth’s composition, which has little carbon compared to the Sun.

Two previously studied white dwarfs have dust of a similar composition, bringing the tally of such stellar gluttons up to eight.

“What was once kind of a freak is now a systematic pattern,” Jura said.

Since asteroids form in the same way as planets, by bulking up through collisions between smaller rocky objects, they have a similar composition to their larger brethren.

That suggests terrestrial planets might have once existed in these systems. “This strengthens suspicions that Earth-like planets are common,” Jura said. (ANI)

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