Doubts about Existence of Gliese-581g

Ever since the announcement of the discovery of exoplanet Gliese 581g, there has been a buzz in the news, on websites, Twitter – pretty much everywhere, about the first potentially habitable extrasolar planet. But the past couple of days there has been a different sort of buzz about this distant world. Two stories have surfaced and they both can’t be true. The first one is fairly off the deep end: an astrophysicist from Australia claims that while doing a SETI search two years ago, he picked up a “suspicious signal” from the vicinity of the Gliese 581 system, and a couple of websites have connected some dots between that signal and a potentially habitable Gliese 581g.
The second one is more sobering. At an International Astronomical Union meeting this week, other astronomers have raised doubts whether Gliese 581g actually exists. Unless you’ve been under a rock the past two weeks, you likely know that this newest and most promising of potential habitable extra solar planets was described by the scientists who discovered it as a rocky world about 3 times the mass of Earth, and it orbits within the red dwarf star’s habitable zone, the place that is just right for water to remain as a liquid on a planetary surface. And it is fairly close to us, too, at about 20 light years away, located in the constellation Libra.
Also announced was the discovery of planet ‘f’, a 7- Earth mass planet with a 433-day orbit around Gliese 581. Astronomer Steven Vogt announced the discoveries by his team, which used the HIRES instrument on the Keck I telescope in Hawaii. They also used 119 measurements from the HARPS instrument on the La Silla telescope at the European Southern Observatory in Chile.
On Monday, Steinn Siggurdson broke the news on his Dynamics of Cats blog that an astronomer who works on HARPS data at the Geneva Observatory, said at the IAU meeting this week that his team could not confirm the existence of Gliese 581 g. In an article on the Astrobiology Magazine website today (Tuesday) the astronomer, Francesco Pepe, said that not only can they not confirm the existence of planet ‘g’, but also the ‘f’ planet.
In 2009, the Geneva team announced the discovery of planet ‘e’ in the Gliese 581 solar system. At approximately 1.9 Earth masses, this ‘e’ planet is the lowest mass extrasolar planet found at that time, and has a 3.15-day orbital period around the star.Pepe said they have studied this planet-rich system frequently, gathering a total of 180 data points in 6.5 years (with about 60 of those data points since 2009) and they can only see evidence of the 4 previously announced planets b, c, d, and e.
There is a signal which could possibly be f, but the signal amplitude of this potential fifth planet is very low and basically at the level of the measurement noise, said Pepe..

Global warming theory in chaos after report finds increased solar activity may COOL the Earth

A puzzling discovery has raised a question mark over the Sun's impact on climate change and could provide ammunition for sceptics, it was revealed today. Until now it has been assumed that less activity from the Sun equates to less warming of the Earth. But the new research, which focuses on a three-year snapshot of time between 2004 and 2007, suggests the opposite may be true.
As solar activity waned at the end of one of the Sun's 11-year cycles, the new data show the amount of energy reaching the Earth at visible wavelengths rose rather than fell. Scientists believe it may also be possible that during the next up-turn of the cycle, when sun activity increases, there might be a cooling effect at the Earth's surface.
A further twist arises from the fact that over the past century, overall solar activity has been increasing. If the new findings apply to long as well as short time periods, this could translate into a small degree of cooling rather than the slight warming effect shown in existing climate models. It would effectively turn received wisdom on its head. Sceptics are likely to say the results further undermine the reliability of climate change science, especially with regard to solar effects.
Professor Joanna Haigh, from Imperial College London, who led the study, said: 'These results are challenging what we thought we knew about the Sun's effect on our climate. However, they only show us a snapshot of the Sun's activity and its behaviour over the three years of our study could be an anomaly.
'We cannot jump to any conclusions based on what we have found during this comparatively short period and we need to carry out further studies to explore the sun's activity and the patterns that we have uncovered on longer timescales.
'However, if further studies find the same pattern over a longer period of time, this could suggest that we may have overestimated the sun's role in warming the planet, rather than underestimating it.' Speaking at a news briefing in London, she denied that it would fuel scepticism about climate change research. 'I think it doesn't give comfort to the climate sceptics at all,' she said. 'It may suggest that we don't know that much about the Sun. It casts no aspersions at all upon the climate models.'
The research, published in the journal Nature, is based on data from a satellite called SORCE (Solar Radiation and Climate Experiment) that has been measuring the Sun's energy output at X-ray, ultraviolet, visible, and near-infrared wavelengths.
Prof Haigh's team found that, above an altitude of 28 miles, concentrations of ozone in the atmosphere increased as total solar output decreased. The ozone rise accompanied a steep fall in levels of ultraviolet radiation. Closer to the ground, an increase in visible radiation caused heating of the lower atmosphere.
'At face value, the data seem incredibly important,' Michael Lockwood, a space physicist at the University of Reading, told.
'If solar activity is out of phase with solar radiative forcing, it could change our understanding of how processes in the troposphere and stratosphere act to modulate Earth's climate.' 'The findings could prove very significant when it comes to understanding, and quantifying, natural climate fluctuations,' he added.
'But no matter how you look at it, the Sun's influence on current climate change is at best a small natural add-on to man-made greenhouse warming.' 'All the evidence is that the vast majority of warming is anthropogenic. It might be that the solar part isn't quite working the way we thought it would, but it is certainly not a seismic rupture of the science.'

50 Years of Exobiology and Astrobiology

In 1959, NASA funded its first exobiology investigation, a life-detection experiment for Viking mission to Mars. In 1960, the agency established an exobiology program, whose early managers adopted an approach to advancing this field of study by funding forward-thinking, boundary-bending, multidisciplinary research projects that other funding sources tended to judge as too risky.

NASA’s Viking mission included three exobiology experiments designed to look for evidence of life on Mars. By the 1980s, NASA expanded its exobiology program to encompass studies of evolutionary biology. In the 1990s, NASA again expanded the breadth and depth of this program, broadening the boundaries of “exobiology” to establish “astrobiology” as a program encompassing studies of chemical evolution in interstellar space, the formation and evolution of planets, and the natural history of Earth in addition to exobiology and evolutionary biology.

Today NASA’s Astrobiology Program addresses three fundamental questions: How does life begin and evolve? Is there life beyond Earth and, if so, how can we detect it? What is the future of life on Earth and in the universe? In striving to answer these questions and improve understanding of biological, planetary and cosmic phenomena and relationships among them, experts in a range of relevant disciplines are participating in astrobiology research and helping to advance the enterprise of space exploration.

British university scientists win Nobel prize for physics for discovery of 'graphene' - an atom-thick carbon layer 200 times stronger than steel

Graphene could lead to new super-fast electronics

Bonds between carbon atoms are the strongest in nature

Novoselov is youngest Nobel laureate since 1973

Two British-based scientists have shared the Nobel Prize for physics for their discovery of a new material that is only an atom thick and which could change the future of electronics. Russian-born Andre Geim and Konstantin Novoselov, both from Manchester University, today won the prize for their 'groundbreaking experiments' with graphene - a microscopic flake of carbon.
The award comes after yesterday's long-awaited Nobel prize for medicine for British scientist Professor Richard Edwards - the inventor of IVF. Since its discovery in 2004 by the pair, graphene has rapidly become one of the hottest topics in materials science and solid-state physics.
The Royal Swedish Academy of Sciences said that their experiments with graphene could lead to the development of new materials and 'the manufacture of innovative electronics'. Geim, 51, is a Dutch national while Novoselov, 36, holds British and Russian citizenship. Both are natives of Russia and started their careers in physics there. Geim said he was shocked by the announcement but planned to go back to work as usual today. 'My plan for today is to go to work and finish up a paper that I didn't finish this week,' he said. 'I just try to muddle on as before.'
Professor Konstantin Novoselov said: 'I was really shocked when I heard the news and my first thought was to go to the lab and tell the team.' The pair extracted the super-thin material from a piece of graphite such as that found in ordinary pencils using sticky tape. 'Playfulness is one of their hallmarks, one always learns something in the process and, who knows, you may even hit the jackpot,' the committee said in its release.
One millimetre of graphite actually consists of 3 million layers of graphene stacked on top of each other, although they are weakly held together. Graphene was discovered at Manchester University in 2004. It is a single atomic layer of carbon atoms bound in a hexagonal network.
The bonds between the carbon atoms are the strongest in nature and the free electrons are highly mobile. It not only promises to revolutionise semiconductor, sensor, and display technology, but could also lead to breakthroughs in fundamental quantum physics research. It is often depicted as an atomic-scale chicken wire made of carbon atoms and their bonds. Scientists believe it could one day be used to make transparent conducting materials, biomedical sensors and even extremely light, yet strong, aircraft of the future.
Similar to another important nanomaterial - carbon nanotubes - graphene is incredibly strong - around 200 times stronger than structural steel. Geim last year received the prestigious Korber European Science Award for his discovery of two-dimensional crystals made of carbon atoms, particularly graphene, the university said on its website. It said the discovery 'has the potential to revolutionise the world of microelectronics'.
Dr Mark Miodownik, Head of the Materials Research Group, King's College London, said: 'The award of this Nobel Prize will bring a smile to the face of every scientist because it shows you can still get a Nobel Prize by mucking about in a lab. 'Professors Geim and Novoselov happened across graphene, a new material that has the potential to revolutionise electronics, by discovering they could pluck atomic layers of carbon from the lead of a pencil using nothing more sophisticated than sticky tape.
'It turns out that anyone who has ever held a pencil could have discovered this amazing new material, but it was Professors Geim and Novoselov who took the time to look carefully. Bravo!
'Another reason to recognise that British science is a special culture, admired throughout the world for its originality and genius, and needs to be nurtured not cut by the government if they want to foster future technology and wealth in the UK.' University of Manchester President and Vice-Chancellor Nancy Rothwell said: 'This is fantastic news. We are delighted that Andre and Konstantin’s work on graphene has been recognised at the very highest level by the 2010 Nobel Prize Committee.
'This is a wonderful example of a fundamental discovery based on scientific curiosity with major practical, social and economic benefits for society.' Professor David Delpy, Chief Executive of the EPSRC, said: 'This work represents an enormously important scientific development. An exciting new material that has a huge range of applications and will no doubt bring significant benefits to the UK economy.'
The 2010 Nobel Prize announcements started yesterday with the medicine award going to British researcher Robert Edwards for work that led to the first test tube baby.

Q-A About Habitable Planet Gliese 581g

A newfound Earth-sized planet discovered in the habitable zone of a nearby star looks very promising for the possibility of extraterrestrial life, but many unknowns remain. The planet, Gliese 581g, is one of two new worlds discovered orbiting the red dwarf star Gliese 581, which now has a family of planets that totals six. [Tour the six Gliese 581 Planets] . Here is Starry Messenger's look at what scientists know so far about the intriguing world, as well as a few questions that don't quite have answers yet. Consider it a new entry into Earth's own hitchhiker's guide to the galaxy -

How do I say the planet's name?
 
Gliese 581g may look like it should rhyme with "Grease," but it is actually pronounced as two-syllables as (Glee-zuh). The name comes from the German astronomer Wilhelm Gliese, who catalogued the planet's parent star Gleise 581 as part of a star survey first published in 1957.

Where is Gliese 581g?

The planet Gliese 581g orbits the red dwarf star Gliese 581, which sits 20 light-years from Earth in the constellation Libra. One light-year is about 6 trillion miles (10 trillion km).


How far is it from the parent star?

Early estimates suggest Gliese 581g is 0.15 astronomical units from its star. One astronomical unit is the average distance between the Earth and sun, which is approximately 93 million miles (150 million km). That distance means the planet is close enough to its star so that it can complete an orbit in a little less than 37 days. One of its sibling planets was closer to the hot edge of the habitable zone around the star Gliese 581, and one was farther out the colder edge of the habitable zone. Gliese 581g is located just right between the two.

What is a habitable zone?


Think of a star's habitable zone as the swath of space surrounding a star where conditions for life as we know it are possible. Closer in, a planet roasts. Farther out, it freezes. Planets within that habitable zone, also known as the Goldilocks zone, have a range of surface temperatures that allow for readily available liquid water and other conditions that may support the rise of life. This cosmic sweet spot can vary, because it depends upon the type of star and the point in time for any given star's lifespan.
For instance, our sun's current habitable zone is farther out than that of the star Gliese 581, a red dwarf about 50 times dimmer than our sun. The cooler red dwarf allows the Gliese 581 planets to orbit much closer and still remain in the habitable zone.
A planet within the habitable zone does not have a guaranteed chance of originating life, because biology also depends upon the planet's size and a host of conditions, including chemical makeup. But what little researchers know about Gliese 581g makes it a highly promising candidate.

How big is Gliese 581g in relation to Earth?


The planet is lumped into the "nearly Earth-sized" category. It is between three and four times the mass of our Earth — bigger, but small enough to be rocky rather than gaseous. Its radius is anywhere between 1.3 and two times the size of Earth.

How much would I weigh on Gliese 581g?

An Earth-sized planet with three times the mass of our planet would pull down on your body with three times the force of Earth's standard gravity. That means if you weighed 120 pounds on Earth, you would weigh about 120 x 3 pounds on an Earth-sized planet with three times the mass, or 360 pounds.
But Gliese 581g also has a somewhat larger radius, so that also factors into the equation. A 120 pound person would weigh about 213 pounds on Gliese 581g at the lower end of the size and mass estimates. This all remains theoretical until astronomers can pin down the actual size and mass.

What's it like on the surface?

There is no solid evidence at the moment that suggests what surface conditions might be like, or even if liquid water and an atmosphere are actually present.What researchers know is that the planet exists at the right distance from its star to have liquid water. It's also at the right distance to have an atmosphere which can protect that water, if exists on the surface.
But one of the planet's discoverers, astronomer Steven Vogt of the University of California, Santa Cruz, pointed out that "it's pretty hard to imagine that water wouldn't be there." He likened it to the examples of the Earth, its moon, Mars, and the moons of Jupiter and Saturn. He also noted that the Orion Nebula is making enough water every 24 seconds to fill all the oceans of the Earth. Researchers also know that the planet is tidally locked to its star. That means one side experiences eternal daylight, and the other side experiences unending darkness. Such a locked configuration helps to stabilize the planet's surface climate, Vogt said.
3-D global circulation models have shown that the temperature differences on the day and night sides of the planet would not be enough for water to either freeze or boil off. They also suggest that the atmospheric circulation and wind patterns would be relatively benign.

Does it have moons?

There's one called Pandora...just kidding! There's no info on any moons around Gliese 581g, or around any other planets in its solar system yet. But astronomers have long assumed that alien planets could have moons, and that some of the moons might harbor life.


How long would it take to get there?

This question depends upon how fast you travel. Given our current lack of Star Trek's warp drives, any interstellar expedition would have to travel far slower than the speed of light.A spaceship traveling at a one-tenth of the speed of light would reach Gliese 581g within about 220 years, Vogt said. That would allow the spaceship to begin getting close-up pictures and a sense of the planet's atmosphere.That time scale is not promising for existing human lifespans, but robotic explorers could more easily take up the challenge. However, the fastest spaceships built so far don't come anywhere near even that one-tenth light-speed mark.

What kind of life would we expect to find?

Any discussion about alien life on Gliese 581g is purely speculative at this point, according to co-discoverer Paul Butler of the Carnegie Institution of Washington, in Washington, D.C. Butler took a more cautionary approach as opposed to Vogt, who said his gut feeling told him "the chances of life on this planet are 100 percent." Still, even Butler noted that anywhere you find water on Earth, you find life. He suggested that a similar condition should hold for almost anywhere in the universe, including Gliese 581g if it does hold water.


Why doesn't the planet have a real name?

The planet is called Gliese 581g because its star, Gliese 581, is designated "a," and the four previously discovered planets in the system are called b, c, d and e. But Vogt said that he has unofficially begun calling the planet "Zarmina's World," in honor of his wife.

What would aliens living on Gliese 581 see if they looked toward our sun?

You remember that we don't have evidence of alien life on the planet yet, right? But assuming they exist, aliens could spot our own sun as star in their sky without requiring any telescopes or binoculars. If the alien astronomers had our current level of technology, they would be also able to easily detect Neptune, and possibly Jupiter and Saturn.

...Hey Tom, It's America !

Susan Reverby describes her finding that several hundred Guatemalans were exposed to syphilis by the US Public Health Service.
Susan Reverby is a historian and professor of women's and gender studies at Wellesley College near Boston in Massachusetts. She is an authority on the notorious Tuskegee experiments, during which treatment was withheld from more than 600 African American men with syphilis. Her recent discovery that the US Public Health Service exposed several hundred Guatemalans to the disease in an undocumented research project in 1946–48 led last week to an official apology from the United States to the Guatemalan government and the promise of a full investigation.

Why did the US government do this research?

By 1946 it was known that syphilis could be cured with penicillin. The primary aim of the study was to look at whether penicillin could also be used as a prophylaxis to get rid of the disease before it established itself in the body. They were looking for something that would be more successful than the 'pro-kits' soldiers had been given during the Second World War, which required them to apply a mercury-based ointment. As you can imagine, there was not a lot of compliance with that approach. They were also interested in whether or not someone could be re-infected with syphilis once cured by penicillin.
The arrangements were set up through Juan Funes, a Guatemalan doctor who had previously trained with the US Public Health Service (PHS) and was then the chief of the venereal disease control division of the Guatemalan Sanidad Publica. Funes and [PHS researcher] John Cutler, who later participated in the Tuskegee experiments, essentially did the study together.

How was the study conducted?

Prostitution was legal in Guatemala, as was bringing in a prostitute for sexual servicing of prisoners in the central penitentiary. They plied some of the prisoners with alcohol and sent in prostitutes whom they knew were infected with syphilis. When not enough infection appeared and they couldn't get enough cases, they made an inoculum. In later tests, they abraded people's bodies — their forearms, cheeks or penises — and applied the inoculum to a piece of cotton or gauze that was held to the abrasion for an hour and a half to two hours. But they had trouble transferring the infection this way, and eventually interest waned. By 1948, the studies were called off. [The US Centers for Disease Control and Prevention (CDC) subsequently found that 427 of 696 subjects were judged to be infected; 369 of those subsequently received "adequate treatment" with penicillin.]

Were these experiments approved?

You can't just walk into the Guatemalan central penitentiary and start doing something like this without someone in charge saying yes. Likewise for the National Mental Health Hospital, where later studies were done. At the mental hospital, Cutler and Funes were able to arrange access by giving the institution things like a projector, and metal plates and utensils. They also provided the anti-epileptic drug Dilantin [phenytoin], because a lot of people in the hospital were actually epileptics and had no medicine to help them control their seizures. That was the trade-off with the asylum keepers.

Was any of this work ever published?

No. In the early 1950s, Cutler was part of a syphilis inoculation project in Sing Sing Prison in New York. That study is published and they make it clear that they asked the permission of the prisoners. They don't reference the Guatemala work. I think they knew it was on an ethical edge. And there were internal questions in the PHS about what they were doing.
But at the time, syphilis was an enormously debilitating disease that health officials were very worried about. They thought they were at war with the disease and they were trying to find things that would help. In a war there are soldiers. I think they saw their subjects as soldiers in that war.

How did you come across all this?

Two years ago, while I was doing research at the University of Pittsburgh, I learned that Cutler, who had taught there, had left papers behind. I asked to see the papers in case there were any documents about Tuskegee I had not already seen. What I found was the Guatemalan material. I was shocked. I could see the papers were talking about inoculations. I've been working on Tuskegee for two decades now and I've spent a lot of time explaining to people that no one was given syphilis in Tuskegee. So you can imagine what it was like to be sitting there reading this. It was just unbelievable.

What happened next?

After completing my book Examining Tuskegee I went back to the University of Pittsburgh in June 2009 and re-did my research on the Guatemalan study to make sure I had it right. I wrote about it in an article that will be published [in the Journal of Policy History] this January. I gave a copy of it to David Sencer, who was the CDC director when Tuskegee broke in 1972 and who I've been in contact with since I interviewed him for the book. He felt this was important and asked if he could take it to people at the CDC. They, in turn, were shocked enough to send a syphilis expert back to Pittsburgh to look at the data. He confirmed what I had found and then it went up the chain of command.

What can today's researchers learn from this?

Most US drug trials are now conducted internationally. We have controls in the United States, but what's being done elsewhere in the world? If the Guatemalan study had been done by a private drug company, I never would have known about it. The lesson for today is the importance of institutional review boards, and of making sure that informed consent is really understood and applied in international trials.
 

Courtesy – Nature