Interesting stuff… TGO
Refer to story below. Source: SPACE.com
NASA’s Hubble Space Telescope has detected water in the atmospheres of five planets
The five exoplanets with hints of water are all scorching-hot, Jupiter-size worlds that are unlikely to host life as we know it. But finding water in their atmospheres still marks a step forward in the search for distant planets that may be capable of supporting alien life, researchers said.
“We’re very confident that we see a water signature for multiple planets,” Avi Mandell, of NASA’s Goddard Space Flight Center in Greenbelt, Md., lead author of one of the studies, said in a statement. “This work really opens the door for comparing how much water is present in atmospheres on different kinds of exoplanets — for example, hotter versus cooler ones.”
The two research teams used Hubble’s Wide Field Camera 3 to analyze starlight passing through the atmospheres of the five “hot Jupiter” planets, which are known as WASP-17b, HD209458b, WASP-12b, WASP-19b and XO-1b.
The atmospheres of all five planets showed signs of water, with the strongest signatures found in the air of WASP-17b and HD209458b.
“To actually detect the atmosphere of an exoplanet is extraordinarily difficult. But we were able to pull out a very clear signal, and it is water,” Drake Deming of the University of Maryland, lead author of the other recent study, said in a statement.
Water is thought to be a common constituent of exoplanet atmospheres and has been found in the air of several other distant worlds to date. But the new work marks the first time scientists have measured and compared profiles of the substance in detail across multiple alien worlds, researchers said.
The water signatures were less intense than expected in all cases, likely because the five hot Jupiters are surrounded by a haze of dust, researchers said.
“These studies, combined with other Hubble observations, are showing us that there are a surprisingly large number of systems for which the signal of water is either attenuated or completely absent,” Heather Knutson of the California Institute of Technology in Pasadena, a co-author on Deming’s paper, said in a statement. “This suggests that cloudy or hazy atmospheres may in fact be rather common for hot Jupiters.”
The study led by Mandell came out today (Dec. 3) in The Astrophysical Journal, while the paper led by Deming was published in September in the same journal.
BERLIN (AP) — The most violent nations in the Middle East are perceived to be the region’s most corrupt and are getting worse as political instability allows abuses to flourish, according to a survey released Tuesday by an international watchdog group.
Transparency International’s annual Corruption Perceptions Index ranks more than four-fifths of countries in the Middle East below 50 on a scale where zero is a country perceived to be highly corrupt and 100 perceived to be very clean. Countries in the region scored an average 37, below the global average of 43.
Three countries that have faced persistent upheaval dropped notably over the past year, with Yemen’s rating falling five points to 18, Syria dropping nine points to 17, and Libya down six points to 15. Iraq also dropped from 18 to 16.
“Imagine what it takes for a country to root out corruption — it always takes institutions with people in them who have levels of integrity and a system of independent oversight,” said Christoph Wilcke, Transparency’s director for Middle East and North Africa.
“In conflict situations, all of that goes out of the window right away.”
The index measures the perception of corruption in the public sector. Wilcke said that there is a general feeling of corruption across the board in the Middle East, including police, judiciary, and government procurement offices.
“Almost all sectors entrusted with public government functions are seen as corrupt,” he said.
The survey of 177 countries is based on local and international experts’ opinions of public sector corruption.
Denmark and New Zealand tied for first place with scores of 91, followed by Finland, Sweden and Norway. Australia and Canada tied in ninth with scores of 81. Britain was 14th with 76 and the United States tied with Uruguay in 19th place with a score of 73.
Afghanistan, North Korea and Somalia tied for last place with scores of 8.
The survey, first conducted in 1995, draws on a variety of sources that capture perceptions of corruption, including World Bank and World Economic Forum assessments, the African Development Bank’s governance ratings, and Transparency International’s own Bribe Payers Survey.
Greece, one of the countries hit hardest by the European financial crisis, ranked in 80th place with a score of 40 , though that was still an improvement of four points over last year’s result. By contrast Spain, whose economy is also suffering, dropped six points to 59 points and placed 40th on the list.
Transparency’s Western Europe coordinator, Valentina Rigamonti, said that while Spain has seen several scandals and has approved little new anti-corruption legislation, Greece has announced an anti-corruption drive, convicted a former minister on embezzlement charges and has taken other action.
“These are really little steps in the fight against corruption but they are signs the government is trying to do something,” Rigamonti said. “The government showed they can do something but now, and in the long term, we need to see some more changes — especially in implementation.”
Most significant in Europe, however, is that the perception in most countries changed very little, she said.
“It’s stagnation and governments need to act more,” Rigamonti said. “Corruption is still a big problem in Europe.”
Refer to story below. Source: SPACE.com
If life does exist anywhere else in the universe, it may only be fleeting. Now scientists are researching how signs of life might look on dying planets.
Astronomers have discovered hundreds of distant alien planets in the past two decades. Future missions could detect potential signs of life called biosignatures on those worlds, such as oxygen or methane in their atmospheres.
Astrobiologist Jack O’Malley-James at the University of St. Andrews in Fife, Scotland and his colleagues noted that biosignatures of life on Earth have not remained the same over time, but have altered considerably over its history. This led the researchers to speculate about how Earth and other planets might look in the future.
“Astrobiology as a field seems to put a lot more focus on the origins of life and how to find life beyond Earth, but less emphasis is put on the end of life, which is what got me interested in finding out more about how biospheres on other planets might meet their ends, and by extension, how long we could expect to detect life on a habitable planet over the course of its habitable lifetime,” said O’Malley-James, the lead author of the study.
The scientists were testing a computer model of the climates and biospheres — the overall life — of possible exoplanets.
“That was when the idea came about to run this model forward in time to see when all water and all life would disappear from the planet,” O’Malley-James said.
The Sun is a middle-aged star, currently about 4.6 billion years old. In the later stages of its evolution, about 2 billion to 3 billion years from now, the Sun will grow much hotter, leading to much higher surface temperatures on the future Earth and thus far harsher environments for any last life to grow and survive on the planet.
The research team modeled the biosignature gases Earth’s biosphere would generate up to 2.8 billion years from the present.
“The most exciting thing about these results is that they suggest that we could potentially detect the presence of life on a planet even at the very end of its habitable lifetime, when the diversity of life and population sizes are considerably reduced compared to what we see on Earth today,” O’Malley-James toldAstrobiology Magazine.
The death of Earth’s biosphere as it exists today would start with plants dying off. Rising temperatures cause silicon-loaded rocks known as silicates to wear away, increasing their absorption of carbon dioxide. The resulting drop in atmospheric carbon dioxide, which plants need in order to generate energy from sunlight, would eventually bring an end to the age of plants.
The extinction of plants would both curtail atmospheric oxygen levels and remove the primary source of food from most ecosystems, leading to the simultaneous extinction of animals, from large vertebrates to smaller ones, with invertebrates having the longest stay of execution. All in all, the researchers calculated Earth’s surface would become largely uninhabitable between 1.2 billion and 1.85 billion years from the present.
Still, life is hardy, so microbes could last for much longer than more complex organisms on a dying Earth. After the extinction of plants and animals, the scientists reasoned the planet’s future biosphere will be much like its early biosphere in consisting mainly of single-celled microbes. Without plants to help generate oxygen, atmospheric oxygen would eventually reach negligible levels, triggering a relatively quick shift — within a few million years — toward microbes that can survive without oxygen. The final survivors of Earth could persist either in caves, deep underground, or in relatively cool refuges at high altitudes until roughly 2.8 billion years from now, when the Sun will probably make the planet too hot for astronomers to detect any life from a distance.
The scientists calculated the extinction of higher plants would lower atmospheric oxygen and ozone levels to concentrations undetectable by astronomers by about 1.11 billion years from now. Still, this drop in oxygen could mean levels of the volatile compound isoprene could build up in the air, potentially serving as a biosignature until plants go extinct. Isoprene is a biological substance that normally has a very short lifetime in the atmosphere, since it quickly reacts with oxygen.
The death of plants and animals would also generate large amounts of decaying matter that would release compounds such as methanethiol into the atmosphere. This gas is only known to come from biological sources — although sunlight rapidly breaks this gas down, the resulting gas, ethane, could serve as a potential biosignature until all plants and animals go extinct.
Methane could also be a biomarker when all other biomarker gases become undetectable in a dying planet’s atmosphere. In fact, far-future levels of methane in Earth’s atmosphere could be 10 times higher than the present — methane-producing bacteria get more of the carbon dioxide they need as fuel because plants are no longer there to remove the carbon dioxide. Still, the researchers caution life is not the only source of methane — volcanoes and chemical reactions involving volcanic rocks can generate the gas as well.
The scientists also conjecture that clouds might serve as homes to potential biosignatures on a dying planet. Once the planet’s surface becomes too hot to live, microbes could find refuge in the clouds — microorganisms are known to exist in Earth’s atmosphere today, although it remains uncertain whether they are just passing through before falling back down or whether they actively live in the sky. Airborne microorganisms could help generate unexpectedly large cloud droplets in the atmospheres of arid planets, the researchers say. In addition, vegetation could serve as a detectable biosignature until higher plants go extinct — leaves cause a red edge to appear in the spectrum of light reflected off Earth.
One major confounding factor into how a dying alien planet might look could be the influence of extraterrestrial intelligence.
“Intelligent life is difficult to factor in when making these kind of predictions,” O’Malley-James said. “It’s certainly possible that intelligent life could play a role in mitigating these changes to the far-future environment, perhaps by some form of geoengineering [artificial changes to the land, sea or air], or even moving the planet out to orbit in a cooler position. Predicting what that would do to a planet’s biosignatures would be quite a challenge, but it may simply make the planet’s biosphere appear younger than we would expect given the age of the planet.”
All in all, when astronomers start finding habitable-zone planets circling older stars, “it will be useful to know if we could expect to see any signs of life and, if we can, what signatures that life might leave for us to detect, because the biosphere on a dying planet would be very different to the life we are familiar with on Earth today,” O’Malley-James said.
The next step with this avenue of research is to start applying it to real examples astronomers have discovered of older, habitable-zone planets around Sun-like stars, O’Malley-James said. “There are not very many of these yet, so this may involve some modeling of theoretical planets around chosen nearby examples of older stars,” he noted. “It’s likely that these worlds would not be nice exact copies of Earth, so this may impact the timeline of events that lead up to the end of life on that particular planet.”
O’Malley-James is also investigating whether Mars could serve as a template for an alien planet that has reached the end of its habitable lifetime — “in this case, by becoming cold and dry,” he said. The researchers would adapt their existing computer model “to simulate Mars and populate all the potentially habitable regions on the planet with microbes that could live there, with the aim of adding to the suite of possible biosignatures for dying biospheres.”
O’Malley-James and his colleagues detailed their findings in the International Journal of Astrobiology.