Tag: life on earth (page 2 of 8)

Why science is so hard to believe?

 
In the recent movie “Interstellar,” set in a futuristic, downtrodden America where NASA has been forced into hiding, school textbooks say the Apollo moon landings were faked.


Excerpt from 


There’s a scene in Stanley Kubrick’s comic masterpiece “Dr. Strangelove” in which Jack D. Ripper, an American general who’s gone rogue and ordered a nuclear attack on the Soviet Union, unspools his paranoid worldview — and the explanation for why he drinks “only distilled water, or rainwater, and only pure grain alcohol” — to Lionel Mandrake, a dizzy-with-anxiety group captain in the Royal Air Force.
Ripper: “Have you ever heard of a thing called fluoridation? Fluoridation of water?”
Mandrake: “Ah, yes, I have heard of that, Jack. Yes, yes.”Ripper: “Well, do you know what it is?”
Mandrake: “No. No, I don’t know what it is, no.”
Ripper: “Do you realize that fluoridation is the most monstrously conceived and dangerous communist plot we have ever had to face?” 

The movie came out in 1964, by which time the health benefits of fluoridation had been thoroughly established and anti-fluoridation conspiracy theories could be the stuff of comedy. Yet half a century later, fluoridation continues to incite fear and paranoia. In 2013, citizens in Portland, Ore., one of only a few major American cities that don’t fluoridate, blocked a plan by local officials to do so. Opponents didn’t like the idea of the government adding “chemicals” to their water. They claimed that fluoride could be harmful to human health.

Actually fluoride is a natural mineral that, in the weak concentrations used in public drinking-water systems, hardens tooth enamel and prevents tooth decay — a cheap and safe way to improve dental health for everyone, rich or poor, conscientious brushers or not. That’s the scientific and medical consensus.
To which some people in Portland, echoing anti-fluoridation activists around the world, reply: We don’t believe you.
We live in an age when all manner of scientific knowledge — from the safety of fluoride and vaccines to the reality of climate change — faces organized and often furious opposition. Empowered by their own sources of information and their own interpretations of research, doubters have declared war on the consensus of experts. There are so many of these controversies these days, you’d think a diabolical agency had put something in the water to make people argumentative.
Science doubt has become a pop-culture meme. In the recent movie “Interstellar,” set in a futuristic, downtrodden America where NASA has been forced into hiding, school textbooks say the Apollo moon landings were faked.


The debate about mandated vaccinations has the political world talking. A spike in measles cases nationwide has President Obama, lawmakers and even potential 2016 candidates weighing in on the vaccine controversy. (Pamela Kirkland/The Washington Post)
In a sense this is not surprising. Our lives are permeated by science and technology as never before. For many of us this new world is wondrous, comfortable and rich in rewards — but also more complicated and sometimes unnerving. We now face risks we can’t easily analyze.
We’re asked to accept, for example, that it’s safe to eat food containing genetically modified organisms (GMOs) because, the experts point out, there’s no evidence that it isn’t and no reason to believe that altering genes precisely in a lab is more dangerous than altering them wholesale through traditional breeding. But to some people, the very idea of transferring genes between species conjures up mad scientists running amok — and so, two centuries after Mary Shelley wrote “Frankenstein,” they talk about Frankenfood.
The world crackles with real and imaginary hazards, and distinguishing the former from the latter isn’t easy. Should we be afraid that the Ebola virus, which is spread only by direct contact with bodily fluids, will mutate into an airborne super-plague? The scientific consensus says that’s extremely unlikely: No virus has ever been observed to completely change its mode of transmission in humans, and there’s zero evidence that the latest strain of Ebola is any different. But Google “airborne Ebola” and you’ll enter a dystopia where this virus has almost supernatural powers, including the power to kill us all.
In this bewildering world we have to decide what to believe and how to act on that. In principle, that’s what science is for. “Science is not a body of facts,” says geophysicist Marcia McNutt, who once headed the U.S. Geological Survey and is now editor of Science, the prestigious journal. “Science is a method for deciding whether what we choose to believe has a basis in the laws of nature or not.”
The scientific method leads us to truths that are less than self-evident, often mind-blowing and sometimes hard to swallow. In the early 17th century, when Galileo claimed that the Earth spins on its axis and orbits the sun, he wasn’t just rejecting church doctrine. He was asking people to believe something that defied common sense — because it sure looks like the sun’s going around the Earth, and you can’t feel the Earth spinning. Galileo was put on trial and forced to recant. Two centuries later, Charles Darwin escaped that fate. But his idea that all life on Earth evolved from a primordial ancestor and that we humans are distant cousins of apes, whales and even deep-sea mollusks is still a big ask for a lot of people.
Even when we intellectually accept these precepts of science, we subconsciously cling to our intuitions — what researchers call our naive beliefs. A study by Andrew Shtulman of Occidental College showed that even students with an advanced science education had a hitch in their mental gait when asked to affirm or deny that humans are descended from sea animals and that the Earth goes around the sun. Both truths are counterintuitive. The students, even those who correctly marked “true,” were slower to answer those questions than questions about whether humans are descended from tree-dwelling creatures (also true but easier to grasp) and whether the moon goes around the Earth (also true but intuitive).
Shtulman’s research indicates that as we become scientifically literate, we repress our naive beliefs but never eliminate them entirely. They nest in our brains, chirping at us as we try to make sense of the world.
Most of us do that by relying on personal experience and anecdotes, on stories rather than statistics. We might get a prostate-specific antigen test, even though it’s no longer generally recommended, because it caught a close friend’s cancer — and we pay less attention to statistical evidence, painstakingly compiled through multiple studies, showing that the test rarely saves lives but triggers many unnecessary surgeries. Or we hear about a cluster of cancer cases in a town with a hazardous-waste dump, and we assume that pollution caused the cancers. Of course, just because two things happened together doesn’t mean one caused the other, and just because events are clustered doesn’t mean they’re not random. Yet we have trouble digesting randomness; our brains crave pattern and meaning.
Even for scientists, the scientific method is a hard discipline. They, too, are vulnerable to confirmation bias — the tendency to look for and see only evidence that confirms what they already believe. But unlike the rest of us, they submit their ideas to formal peer review before publishing them. Once the results are published, if they’re important enough, other scientists will try to reproduce them — and, being congenitally skeptical and competitive, will be very happy to announce that they don’t hold up. Scientific results are always provisional, susceptible to being overturned by some future experiment or observation. Scientists rarely proclaim an absolute truth or an absolute certainty. Uncertainty is inevitable at the frontiers of knowledge.
That provisional quality of science is another thing a lot of people have trouble with. To some climate-change skeptics, for example, the fact that a few scientists in the 1970s were worried (quite reasonably, it seemed at the time) about the possibility of a coming ice age is enough to discredit what is now the consensus of the world’s scientists: The planet’s surface temperature has risen by about 1.5 degrees Fahrenheit in the past 130 years, and human actions, including the burning of fossil fuels, are extremely likely to have been the dominant cause since the mid-20th century.
It’s clear that organizations funded in part by the fossil-fuel industry have deliberately tried to undermine the public’s understanding of the scientific consensus by promoting a few skeptics. The news media gives abundant attention to such mavericks, naysayers, professional controversialists and table thumpers. The media would also have you believe that science is full of shocking discoveries made by lone geniuses. Not so. The (boring) truth is that science usually advances incrementally, through the steady accretion of data and insights gathered by many people over many years. So it has with the consensus on climate change. That’s not about to go poof with the next thermometer reading.
But industry PR, however misleading, isn’t enough to explain why so many people reject the scientific consensus on global warming.
The “science communication problem,” as it’s blandly called by the scientists who study it, has yielded abundant new research into how people decide what to believe — and why they so often don’t accept the expert consensus. It’s not that they can’t grasp it, according to Dan Kahan of Yale University. In one study he asked 1,540 Americans, a representative sample, to rate the threat of climate change on a scale of zero to 10. Then he correlated that with the subjects’ science literacy. He found that higher literacy was associated with stronger views — at both ends of the spectrum. Science literacy promoted polarization on climate, not consensus. According to Kahan, that’s because people tend to use scientific knowledge to reinforce their worldviews.
Americans fall into two basic camps, Kahan says. Those with a more “egalitarian” and “communitarian” mind-set are generally suspicious of industry and apt to think it’s up to something dangerous that calls for government regulation; they’re likely to see the risks of climate change. In contrast, people with a “hierarchical” and “individualistic” mind-set respect leaders of industry and don’t like government interfering in their affairs; they’re apt to reject warnings about climate change, because they know what accepting them could lead to — some kind of tax or regulation to limit emissions.
In the United States, climate change has become a litmus test that identifies you as belonging to one or the other of these two antagonistic tribes. When we argue about it, Kahan says, we’re actually arguing about who we are, what our crowd is. We’re thinking: People like us believe this. People like that do not believe this.
Science appeals to our rational brain, but our beliefs are motivated largely by emotion, and the biggest motivation is remaining tight with our peers. “We’re all in high school. We’ve never left high school,” says Marcia McNutt. “People still have a need to fit in, and that need to fit in is so strong that local values and local opinions are always trumping science. And they will continue to trump science, especially when there is no clear downside to ignoring science.”
Meanwhile the Internet makes it easier than ever for science doubters to find their own information and experts. Gone are the days when a small number of powerful institutions — elite universities, encyclopedias and major news organizations — served as gatekeepers of scientific information. The Internet has democratized it, which is a good thing. But along with cable TV, the Web has also made it possible to live in a “filter bubble” that lets in only the information with which you already agree.
How to penetrate the bubble? How to convert science skeptics? Throwing more facts at them doesn’t help. Liz Neeley, who helps train scientists to be better communicators at an organization called Compass, says people need to hear from believers they can trust, who share their fundamental values. She has personal experience with this. Her father is a climate-change skeptic and gets most of his information on the issue from conservative media. In exasperation she finally confronted him: “Do you believe them or me?” She told him she believes the scientists who research climate change and knows many of them personally. “If you think I’m wrong,” she said, “then you’re telling me that you don’t trust me.” Her father’s stance on the issue softened. But it wasn’t the facts that did it.
If you’re a rationalist, there’s something a little dispiriting about all this. In Kahan’s descriptions of how we decide what to believe, what we decide sometimes sounds almost incidental. Those of us in the science-communication business are as tribal as anyone else, he told me. We believe in scientific ideas not because we have truly evaluated all the evidence but because we feel an affinity for the scientific community. When I mentioned to Kahan that I fully accept evolution, he said: “Believing in evolution is just a description about you. It’s not an account of how you reason.”
Maybe — except that evolution is real. Biology is incomprehensible without it. There aren’t really two sides to all these issues. Climate change is happening. Vaccines save lives. Being right does matter — and the science tribe has a long track record of getting things right in the end. Modern society is built on things it got right.
Doubting science also has consequences, as seen in recent weeks with the measles outbreak that began in California. The people who believe that vaccines cause autism — often well educated and affluent, by the way — are undermining “herd immunity” to such diseases as whooping cough and measles. The anti-vaccine movement has been going strong since a prestigious British medical journal, the Lancet, published a study in 1998 linking a common vaccine to autism. The journal later retracted the study, which was thoroughly discredited. But the notion of a vaccine-autism connection has been endorsed by celebrities and reinforced through the usual Internet filters. (Anti-vaccine activist and actress Jenny McCarthy famously said on “The Oprah Winfrey Show,” “The University of Google is where I got my degree from.”)
In the climate debate, the consequences of doubt are likely to be global and enduring. Climate-change skeptics in the United States have achieved their fundamental goal of halting legislative action to combat global warming. They haven’t had to win the debate on the merits; they’ve merely had to fog the room enough to keep laws governing greenhouse gas emissions from being enacted.
Some environmental activists want scientists to emerge from their ivory towers and get more involved in the policy battles. Any scientist going that route needs to do so carefully, says Liz Neeley. “That line between science communication and advocacy is very hard to step back from,” she says. In the debate over climate change, the central allegation of the skeptics is that the science saying it’s real and a serious threat is politically tinged, driven by environmental activism and not hard data. That’s not true, and it slanders honest scientists. But the claim becomes more likely to be seen as plausible if scientists go beyond their professional expertise and begin advocating specific policies.
It’s their very detachment, what you might call the cold-bloodedness of science, that makes science the killer app. It’s the way science tells us the truth rather than what we’d like the truth to be. Scientists can be as dogmatic as anyone else — but their dogma is always wilting in the hot glare of new research. In science it’s not a sin to change your mind when the evidence demands it. For some people, the tribe is more important than the truth; for the best scientists, the truth is more important than the tribe.

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Ancient rocks show life could have flourished on Earth 3.2 billion years ago


photo of red rocks and blue sky
The oldest samples are sedimentary rocks that formed 3.2 billion years ago in
northwestern Australia. They contain chemical evidence for nitrogen
fixation by microbes.R. Buick / UW



Excerpt from
washington.edu

A spark from a lightning bolt, interstellar dust, or a subsea volcano could have triggered the very first life on Earth.
But what happened next? Life can exist without oxygen, but without plentiful nitrogen to build genes – essential to viruses, bacteria and all other organisms – life on the early Earth would have been scarce.

The ability to use atmospheric nitrogen to support more widespread life was thought to have appeared roughly 2 billion years ago. Now research from the University of Washington looking at some of the planet’s oldest rocks finds evidence that 3.2 billion years ago, life was already pulling nitrogen out of the air and converting it into a form that could support larger communities.

“People always had the idea that the really ancient biosphere was just tenuously clinging on to this inhospitable planet, and it wasn’t until the emergence of nitrogen fixation that suddenly the biosphere become large and robust and diverse,” said co-author Roger Buick, a UW professor of Earth and space sciences. “Our work shows that there was no nitrogen crisis on the early Earth, and therefore it could have supported a fairly large and diverse biosphere.”
The results were published Feb. 16 in Nature.

The authors analyzed 52 samples ranging in age from 2.75 to 3.2 billion years old, collected in South Africa and northwestern Australia. These are some of the oldest and best-preserved rocks on the planet. The rocks were formed from sediment deposited on continental margins, so are free of chemical irregularities that would occur near a subsea volcano. They also formed before the atmosphere gained oxygen, roughly 2.3 to 2.4 billion years ago, and so preserve chemical clues that have disappeared in modern rocks.

Even the oldest samples, 3.2 billion years old – three-quarters of the way back to the birth of the planet – showed chemical evidence that life was pulling nitrogen out of the air. The ratio of heavier to lighter nitrogen atoms fits the pattern of nitrogen-fixing enzymes contained in single-celled organisms, and does not match any chemical reactions that occur in the absence of life.

“Imagining that this really complicated process is so old, and has operated in the same way for 3.2 billion years, I think is fascinating,” said lead author Eva Stüeken, who did the work as part of her UW doctoral research. “It suggests that these really complicated enzymes apparently formed really early, so maybe it’s not so difficult for these enzymes to evolve.”

Genetic analysis of nitrogen-fixing enzymes have placed their origin at between 1.5 and 2.2 billion years ago.

“This is hard evidence that pushes it back a further billion years,” Buick said.

Fixing nitrogen means breaking a tenacious triple bond that holds nitrogen atoms in pairs in the atmosphere and joining a single nitrogen to a molecule that is easier for living things to use. The chemical signature of the rocks suggests that nitrogen was being broken by an enzyme based on molybdenum, the most common of the three types of nitrogen-fixing enzymes that exist now. 

Molybdenum is now abundant because oxygen reacts with rocks to wash it into the ocean, but its source on the ancient Earth – before the atmosphere contained oxygen to weather rocks – is more mysterious.

The authors hypothesize that this may be further evidence that some early life may have existed in single-celled layers on land, exhaling small amounts of oxygen that reacted with the rock to release molybdenum to the water.

“We’ll never find any direct evidence of land scum one cell thick, but this might be giving us indirect evidence that the land was inhabited,” Buick said. “Microbes could have crawled out of the ocean and lived in a slime layer on the rocks on land, even before 3.2 billion years ago.”

Future work will look at what else could have limited the growth of life on the early Earth. Stüeken has begun a UW postdoctoral position funded by NASA to look at trace metals such as zinc, copper and cobalt to see if one of them controlled the growth of ancient life.

Other co-authors are Bradley Guy at the University of Johannesburg in South Africa, who provided some samples from gold mines, and UW graduate student Matthew Koehler. The research was funded by NASA, the UW’s Virtual Planetary Laboratory, the Geological Society of America and the Agouron Institute.

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Dinosaurs were NOT wiped out by a global firestorm: Asteroid impact was not hot enough to ignite nearby plants, study claims

Excerpt from dailymail.co.ukBy Jonathan O'Callaghan UK researchers studied the asteroid impact 66 million years agoThey found the heat near the impact site in Mexico was not intense enough to ignite plant materialA heat pulse lasted less than a minute...

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Why Bill Nye ‘The Science Guy’ Calls Evolution ‘Undeniable’ and Creationism ‘Inane’



Picture of thousands of galaxies
Gazing at galaxy clusters like Abell 2218, it's hard to imagine how we fit into the cosmos. Evolution can help with that, says Bill Nye.
Photograph by NASA, ESA, and Johan Richard (Caltech, USA)


Darwin's theory explains so much of the world, from bumblebees to human origins, says the Science Guy.


Excerpt from
By Jane J. Lee

With a jaunty bow tie and boyish enthusiasm, Bill Nye the Science Guy has spent decades decoding scientific topics, from germs to volcanoes, for television audiences. Last February, the former engineer defended the theory of evolution in a televised debate with young-Earth creationist Ken Ham, a vocal member of a group that believes the Earth is only 6,000 years old. Nye's decision to engage Ham kicked up plenty of criticism from scientists and creationists alike.

The experience prompted the celebrity science educator to write a "primer" on the theory of evolution called Undeniable: Evolution and the Science of Creation. In his new book, Nye delights in how this fundamental discovery helps to unlock the mysteries of everything from bumblebees to human origins to our place in the universe.

Who do you hope will read this book?
Grown-ups who have an interest in the world around them, people coming of age who have an interest in science, people who still want to know how the world works.

This is the big concern of mine with respect to the organization Answers in Genesis and Ken Ham and all those guys: their relentless, built-in attempts to indoctrinate a generation of science students on a worldview that is obviously wrong.

I worry about these kids—they're part of my society. We can't raise a generation of students who don't understand the fundamental idea in all of life science, any more than you want to raise a generation of kids who don't understand chemistry or physics or arithmetic.

How and when did you first encounter creationism?
About 20 years ago. I was a member of the Northwest Skeptics, which is the Seattle-based skeptics organization. We met people who insisted that the Earth was 6,000 years old. The inanity took my breath away. When you understand anything about astronomy or have just a rudimentary understanding of radioactivity, the Earth is patently not 6,000 years old. It's silly.

It's been said that a good way of convincing people of something is to appeal to their emotions. What do you think?
That's my business! In the book, I purposely spend a lot of time in the first person. The reason is, we find stories compelling. Stories are how we remember things, how we organize things.

By telling a story in the first person, it's hard to dismiss. If I say, "I remember the time I met Ivan the gorilla," it's really difficult for the listener or reader to go, "No, you don't!"

When you say, "I feel," it's really hard for the reader to say, "No, you don't." Yes, I do. I did a lot of that in the book...

Picture of a sweat bee pollinating a deadly nightshade flower
A fascination with bees and flight drew a young Bill Nye into the world of science and evolution.
Photograph by Mark W Moffett, National Geographic



Picture of the Earth seen from the International Space Station
One of the most fundamental ideas in explaining life on Earth is the theory of evolution, says Nye.
Photograph by NASA Earth Observatory

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Meteorite is ‘hard drive’ from space ~ Researchers decode ancient recordings from asteroid ~ BBC


Pallasite meteorite
The Esquel meteorite consists of gem-quality crystals embedded in metal.



Excert from bbc.com

Researchers have decoded ancient recordings from fragments of an asteroid dating back billions of years to the start of the Solar System. 

They found tiny "space magnets" in meteorites which retain a memory of the birth and death of the asteroid's core.
Like the data recorded on the surface of a computer hard drive, the magnetic signals written in the space rock reveal how Earth's own metallic core and magnetic field may one day die.

The work appears in Nature journal.

Using a giant X-ray microscope, called a synchrotron, the team was able to read the signals that formed more than four-and-a-half billion years ago, soon after the birth of the Solar System.

Start Quote

It's like a cosmic archaeological mission”
Dr James Bryson University of Cambridge
The meteorites are pieces of a parent asteroid that originally came from asteroid belt, between Mars and Jupiter.
They represents the left-over fragments of a planet that failed to form. The magnetic recording within it traps a signal of the precise moments when an iron-rich core formed in the asteroid as well as when it froze, killing its magnetic field.
The new picture of metallic core solidification in the asteroid provide clues about the magnetic field and iron-rich core of Earth.
Core values "Ideas about how the Earth's core evolved through [our planet's] history are really changing at the moment," lead researcher Dr Richard Harrison, from the University of Cambridge, told BBC News.
"We believe that Earth's magnetic field is linked to core solidification. Earth's solid inner core may have started to form at very interesting time in terms of the evolution of life on Earth.
"By studying an asteroid we get to see this in fast forward. We can see the start of core solidification in the magnetic records as well as its end, and start to think about how these processes work on Earth."

Magnetic fieldThe Earth's magnetic field will likely die off when the core completely freezes
The meteorites studied by the team originally fell to Earth in Argentina, and are composed of gem-quality crystals enclosed in a metallic matrix of iron and nickel. 

Tiny particles, smaller than one thousandth the width of a human hair, trapped within the metal have retained the magnetic signature of the parent asteroid from its birth in the early Solar System.

"We're taking ancient magnetic field measurements in nano-scale materials to the highest ever resolution in order to piece together the magnetic history of asteroids - it's like a cosmic archaeological mission," said Dr James Bryson, the paper's lead author. 

"Since asteroids are much smaller than Earth, they cooled much more quickly, so these processes occur on a shorter timescales, enabling us to study the whole process of core solidification."

Prof Wyn William, from the University of Edinburgh, who was not involved in the study, commented: "To be able to get a time stamp on these recordings, to get a cooling rate and the time of solidification, is fantastic. It's a very nice piece of work."

The key to the long-lived stability of the recording is the atomic-scale structure of the iron-nickel particles that grew slowly in the asteroid core and survived in the meteorites. 

Making a final comment on the results, Dr Harrison said: "In our meteorites we've been able to capture both the beginning and end of core freezing, which will help us understand how these processes affected the Earth in the past and provide a possible glimpse of what might happen in the future." 

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New data that fundamental physics constants underlie life-enabling universe

Excerpt from spacedaily.com For nearly half a century, theoretical physicists have made a series of discoveries that certain constants in fundamental physics seem extraordinarily fine-tuned to allow for the emergence of a life-enabling universe.Thi...

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The Best Bet for Alien Life May Be in Planetary Systems Very Different From Ours




Excerpt from wired.com


In the hunt for extraterrestrial life, scientists started by searching for a world orbiting a star just like the sun. After all, the steady warmth of that glowing yellow ball in the sky makes life on Earth possible.

But as astronomers continue to discover thousands of planets, they’re realizing that if (or when) we find signs of extraterrestrial life, chances are good that those aliens will orbit a star quite different from the sun—one that’s redder, cooler, and at a fraction of the sun’s size and mass. So in the quest for otherworldly life, many astronomers have set their sights on these small stars, known as red dwarfs or M dwarfs.

At first, planet-hunting astronomers didn’t care so much about M dwarfs. After the first planet outside the solar system was discovered in 1995, scientists began hunting for a true Earth twin: a rocky planet like Earth with an orbit like ours around a sun-like star. Indeed, the search for that kind of system drove astronomers through most of the 2000s, says astronomer Phil Muirhead of Boston University.

But then astronomers realized that it might be technically easier to find planets around M dwarfs. Detecting another planet is really hard, and scientists rely on two main methods. In the first, they look for a drop in a star’s brightness when a planet passes in front of it. In the second, astronomers measure the slight wobble of a star, caused by the gentle gravitational tug of an orbiting planet. With both of these techniques, the signal is stronger and easier to detect for a planet orbiting an M dwarf. A planet around an M dwarf also orbits more frequently, increasing the chances that astronomers will spot it.

M dwarfs got a big boost from the Kepler space telescope, which launched in 2008. By staring at small patch of the sky, the telescope searches for suddenly dimming stars when a planet passes in front of them. In doing so, the spacecraft discovered a glut of planets—more than 1,000 at the latest count—it found a lot of planets around M dwarfs. “Kepler changed everything,” Muirhead said. Because M-dwarf systems are easier to find, the bounty of such planets is at least partly due to a selection effect. But, as Muirhead points out, Kepler is also designed to find Earth-sized planets around sun-like stars, and the numbers so far suggest that M-dwarfs may offer the best odds for finding life.

“By sheer luck you would be more likely to find a potentially habitable planet around an M dwarf than a star like the sun,” said astronomer Courtney Dressing of Harvard. She led an analysis to estimate how many Earth-sized planets—which she defined as those with radii ranging from one to one-and-a-half times Earth’s radius—orbit M dwarfs in the habitable zone, the region around the star where liquid water can exist on the planet’s surface. According to her latest calculations, one in four M dwarfs hosts such a planet.

That’s higher than the estimated number of Earth-sized planets around a sun-like star, she says. For example, an analysis by astronomer Erik Petigura of UC Berkeley suggests that fewer than 10 percent of sun-like stars have a planet with a radius between one and two times that of Earth’s.

This illustration shows Kepler-186f, the first rocky planet found in a star's habitable zone. Its star is an M dwarf.
This illustration shows Kepler-186f, the first rocky planet found in a star’s habitable zone. Its star is an M dwarf. NASA Ames/SETI Institute/JPL-Caltech


M dwarfs have another thing going for them. They’re the most common star in the galaxy, comprising an estimated 75 percent of the Milky Way’s hundreds of billions of stars. If Dressing’s estimates are right, then our galaxy could be teeming with 100 billion Earth-sized planets in their stars’ habitable zones.

To be sure, these estimates have lots of limitations. They depend on what you mean by the habitable zone, which isn’t well defined. Generally, the habitable zone is where it’s not too hot or too cold for liquid water to exist. But there are countless considerations, such as how well a planet’s atmosphere can retain water. With a more generous definition that widens the habitable zone, Petigura’s numbers for Earth-sized planets around a sun-like star go up to 22 percent or more. Likewise, Dressing’s numbers could also go up.
Astronomers were initially skeptical of M-dwarf systems because they thought a planet couldn’t be habitable near this kind of star. For one, M dwarfs are more active, especially during within the first billion years of its life. They may bombard a planet with life-killing ultraviolet radiation. They can spew powerful stellar flares that would strip a planet of its atmosphere.

And because a planet will tend to orbit close to an M dwarf, the star’s gravity can alter the planet’s rotation around its axis. When such a planet is tidally locked, as such a scenario is called, part of the planet may see eternal daylight while another part sees eternal night. The bright side would be fried while the dark side would freeze—hardly a hospitable situation for life.

But none of these are settled issues, and some studies suggest they may not be as big of a problem as previously thought, says astronomer Aomawa Shields of UCLA. For example, habitability may depend on specific types and frequency of flares, which aren’t well understood yet. Computer models have also shown that an atmosphere can help distribute heat, preventing the dark side of a planet from freezing over.

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Scientists Deem Asteroids Source of Earth’s Oceans



Scientists theorize that asteroids, not comets, created Earth’s oceans with terrestrial water. Photo courtesy of NASA/Don Davis



Excerpt from newsok.com
Wayne Harris-Wyrick: Asteroid impacts that, today, could wipe out life on Earth, made it possible for life to flourish here in the first place by providing the precious water.
Water is rather ubiquitous, cosmically speaking, composed of hydrogen, the most common element in the universe, and oxygen, the third most common. In between is helium, a noble gas that doesn’t play well with other elements.

Water was present in great quantity 4.6 billion years ago when the planets of our solar system took shape. Venus, Earth and Mars formed with copious amounts of water. But Venus’ 900-degree atmosphere boiled it away and broke it down into its constituent parts or combined it with sulfur dioxide gas to create the planet’s thick sulfuric acid cloud cover. Mars’ small size meant weak gravity, so its atmosphere leaked into space, and its water evaporated, which it does with no air pressure above it, and also leaked into space.

Strong, active volcanism, aided by massive asteroid impacts boiled into space most, if not all, of remaining water on all three planets. And yet, today, three quarters of Earth is covered with water. Where did it come from?

For years, astronomers assumed that comets, the most common water-bearing objects in our solar system, brought the water to Earth. But comets formed much farther from the sun than Earth did. The isotopic composition of water differs with distance from the sun.

Thanks to the Rosetta spacecraft, we now know that cometary water doesn’t match terrestrial water. But asteroid water does. Today, asteroids are quite parched, but 4.5 billion years ago, when many asteroids impacted the planets and moons of the inner solar system, water represented a much larger fraction of their mass. And, it appears, they are the source of Earth’s oceans.

It turns out that asteroid impacts that, today, could wipe out life on Earth, made it possible for life to flourish here in the first place by providing the precious water.

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How will the world end? From ‘demonic’ AI to nuclear war — seven scenarios that could end human race




news.nationalpost.com 


Humanity may have already created its own nemesis, Professor Stephen Hawking warned last week. The Cambridge University physicist claimed that new developments in the field of artificial intelligence (AI) mean that within a few decades, computers thousands of times more powerful than in existence today may decide to usurp their creators and effectively end humanity’s 100,000-year dominance of Earth.
This Terminator scenario is taken seriously by many scientists and technologists. Before Prof. Hawking made his remarks, Elon Musk, the genius behind the Tesla electric car and PayPal, had stated that “with artificial intelligence, we are summoning the demon,” comparing it unfavourably with nuclear war as the most potent threat to humanity’s existence.
Aside from the rise of the machines, many potential threats have been identified to our species, our civilization, even our planet. To keep you awake at night, here are seven of the most plausible.
Getty Images / ThinkStock
Getty Images / ThinkStockAn artist's depiction of an asteroid approaching Earth.
1. ASTEROID STRIKE
Our solar system is littered with billions of pieces of debris, from the size of large boulders to objects hundreds of kilometres across. We know that, from time to time, these hit the Earth. Sixty-five-million years ago, an object – possibly a comet a few times larger than the one on which the Philae probe landed last month – hit the Mexican coast and triggered a global winter that wiped out the dinosaurs. In 1908, a smaller object hit a remote part of Siberia and devastated hundreds of square kilometres of forest. Last week, 100 scientists, including Lord Rees of Ludlow, the Astronomer Royal, called for the creation of a global warning system to alert us if a killer rock is on the way.
Probability: remote in our lifetime, but one day we will be hit.
Result: there has been no strike big enough to wipe out all life on Earth – an “extinction-level event” – for at least three billion years. But a dino-killer would certainly be the end of our civilization and possibly our species.
Warner Bros.
Warner Bros.When artificial intelligence becomes self-aware, there is a chance it will look something like this scene from Terminator 3.
2. ARTIFICIAL INTELLIGENCE
Prof. Hawking is not worried about armies of autonomous drones taking over the world, but something more subtle – and more sinister. Some technologists believe that an event they call the Singularity is only a few decades away. This is a point at which the combined networked computing power of the world’s AI systems begins a massive, runaway increase in capability – an explosion in machine intelligence. By then, we will probably have handed over control to most of our vital systems, from food distribution networks to power plants, sewage and water treatment works, and the global banking system. The machines could bring us to our knees without a shot being fired. And we cannot simply pull the plug, because they control the power supplies.

Probability: unknown, although computing power is doubling every 18 months. We do not know if machines can be conscious or “want” to do anything, and sceptics point out that the cleverest computers in existence are currently no brighter than cockroaches.
Result: if the web wakes up and wants to sweep us aside, we may have a fight on our hands (perhaps even something similar to the man vs. machines battle in the Terminator films). But it is unlikely that the machines will want to destroy the planet – they “live” here, too.
Handout/AFP/Getty Images
Handout/AFP/Getty ImagesLaboratory technicians and physicians work on samples during research on the evolving Ebola disease in bats, at the Center for Emerging and Zoonotic Diseases research Laboratory of the National Institute for Communicable Diseases in Pretoria on Nov. 21, 2011.
3. A GENETICALLY CREATED PLAGUE
This is possibly the most terrifying short-term threat because it is so plausible. The reason Ebola has not become a worldwide plague – and will not do so – is because it is so hard to transmit, and because it incapacitates and kills its victims so quickly. However, a modified version of the disease that can be transmitted through the air, or which allows its host to travel around for weeks, symptom-free, could kill many millions. It is unknown whether any terror group has the knowledge or facilities to do something like this, but it is chilling to realize that the main reason we understand Ebola so well is that its potential to be weaponized was quickly realized by defence experts.
Probability: someone will probably try it one day.
Result: potentially catastrophic. “Ordinary” infectious diseases such as avian-flu strains have the capability to wipe out hundreds of millions of people.
AP Photo/U.S. Army via Hiroshima Peace Memorial Museum
AP Photo/U.S. Army via Hiroshima Peace Memorial MuseumA mushroom cloud billows about one hour after a nuclear bomb was detonated above Hiroshima, Japan Aug. 6, 1945.
4. NUCLEAR WAR
This is still the most plausible “doomsday” scenario. Despite arms-limitations treaties, there are more than 15,000 nuclear warheads and bombs in existence – many more, in theory, than would be required to kill every human on Earth. Even a small nuclear war has the potential to cause widespread devastation. In 2011, a study by NASA scientists concluded that a limited atomic war between India and Pakistan involving just 100 Hiroshima-sized detonations would throw enough dust into the air to cause temperatures to drop more than 1.2C globally for a decade.
Probability: high. Nine states have nuclear weapons, and more want to join the club. The nuclear wannabes are not paragons of democracy.
Result: it is unlikely that even a global nuclear war between Russia and NATO would wipe us all out, but it would kill billions and wreck the world economy for a century. A regional war, we now know, could have effects far beyond the borders of the conflict.
CERN)/MCT
CERN)/MCTThis is one of the huge particle detectors in the Large Hadron Collider, a 17 mile-long tunnel under the French-Swiss border. Scientists are searching for evidence of what happened right after- and perhaps before- the Big Bang.
5. PARTICLE ACCELERATOR DISASTER
Before the Large Hadron Collider (LHC), the massive machine at CERN in Switzerland that detected the Higgs boson a couple of years ago, was switched on, there was a legal challenge from a German scientist called Otto Rossler, who claimed the atom-smasher could theoretically create a small black hole by mistake – which would then go on to eat the Earth.
The claim was absurd: the collisions in the LHC are far less energetic than those caused naturally by cosmic rays hitting the planet. But it is possible that, one day, a souped-up version of the LHC could create something that destroys the Earth – or even the universe – at the speed of light.
Probability: very low indeed.
Result: potentially devastating, but don’t bother cancelling the house insurance just yet.
AP Photo/Oculus Rift/Fox
AP Photo/Oculus Rift/FoxThis photo shows a scene fromX-Men: Days of Future Past virtual reality experience. Oxford University philosopher Nick Bostrom has speculated that our universe may be one of countless "simulations" running in some alien computer, much like a computer game.
6. ‘GOD’ REACHES FOR THE OFF-SWITCH
Many scientists have pointed out that there is something fishy about our universe. The physical constants – the numbers governing the fundamental forces and masses of nature – seem fine-tuned to allow life of some form to exist. The great physicist Sir Fred Hoyle once wondered if the universe might be a “put-up job”.
More recently, the Oxford University philosopher Nick Bostrom has speculated that our universe may be one of countless “simulations” running in some alien computer, much like a computer game. If so, we have to hope that the beings behind our fake universe are benign – and do not reach for the off-button should we start misbehaving.
Probability: according to Professor Bostrom’s calculations, if certain assumptions are made, there is a greater than 50% chance that our universe is not real. And the increasingly puzzling absence of any evidence of alien life may be indirect evidence that the universe is not what it seems.
Result: catastrophic, if the gamers turn against us. The only consolation is the knowledge that there is absolutely nothing we can do about it.
AP Photo/Charles Rex Arbogast
AP Photo/Charles Rex ArbogastFloodwaters from the Souris River surround homes near Minot State University in Minot, N.D. on June 27, 2011. Global warming is rapidly turning America the beautiful into America the stormy and dangerous, according to the National Climate Assessment report released Tuesday, May 6, 2014.
7. CLIMATE CATASTROPHE
Almost no serious scientists now doubt that human carbon emissions are having an effect on the planet’s climate. The latest report by the Intergovernmental Panel on Climate Change suggested that containing temperature rises to below 2C above the pre-industrial average is now unlikely, and that we face a future three or four degrees warmer than today.
This will not literally be the end of the world – but humanity will need all the resources at its disposal to cope with such a dramatic shift. Unfortunately, the effects of climate change will really start to kick in just at the point when the human population is expected to peak – at about nine billion by the middle of this century. Millions of people, mostly poor, face losing their homes to sea-level rises (by up to a metre or more by 2100) and shifting weather patterns may disrupt agriculture dramatically.
Probability: it is now almost certain that CO2 levels will keep rising to 600 parts per billion and beyond. It is equally certain that the climate will respond accordingly.
Result: catastrophic in some places, less so in others (including northern Europe, where temperature rises will be moderated by the Atlantic). The good news is that, unlike with most of the disasters here, we have a chance to do something about climate change now.

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Are we sending aliens the right messages?


(Nasa)


bbc.com

Artist Carrie Paterson has long dreamed of beaming messages far out to the emptiness of space. Except her messages would have an extra dimension – smell.

By broadcasting formulae of aromatic chemicals, she says, aliens could reconstruct all sorts of whiffs that help to define life on Earth: animal blood and faeces, sweet floral and citrus scents or benzene to show our global dependence on the car. This way intelligent life forms on distant planets who may not see or hear as we do, says Paterson, could explore us through smell, one of the most primitive and ubiquitous senses of all.
(Wikipedia)
It is nearly 40 years since the Arecibo facility sent messages out into space (Wikipedia)

Her idea is only the latest in a list of attempts to hail intelligent life outside of the Solar System. Forty years ago this month, the Arecibo radio telescope in Puerto Rico sent an iconic picture message into space – and we’ve arguably been broadcasting to aliens ever since we invented TV and radio.

However in recent years, astronomers, artists, linguists and anthropologists have been converging on the idea that creating comprehensible messages for aliens is much harder than it seems. This week, Paterson and others discussed the difficulties of talking to our cosmic neighbours at a conference called Communicating Across the Cosmos, held by Seti (Search for Extraterrestrial Intelligence). It seems our traditional ways of communicating through pictures and language may well be unintelligible – or worse, be catastrophically misconstrued. So how should we be talking to ET?

Lost in translation?

We have always wanted to send messages about humanity beyond the planet. According to Albert Harrison, a space psychologist and author of Starstruck: Cosmic Visions in Science, Religion and Folklore, the first serious designs for contacting alien life appeared two centuries ago, though they never got off the ground.


In the 1800s, mathematician Carl Gauss proposed cutting down lines of trees in a densely forested area and replanting the strips with wheat or rye, Harrison wrote in his book. “The contrasting colours would form a giant triangle and three squares known as a Pythagoras figure which could be seen from the Moon or even Mars.” Not long after, the astronomer Joseph von Littrow proposed creating huge water-filled channels topped with kerosene. “Igniting them at night showed geometric patterns such as triangles that Martians would interpret as a sign of intelligence, not nature.”

But in the 20th Century, we began to broadcast in earnest. The message sent by Arecibo hoped to make first contact on its 21,000 year journey to the edge of the Milky Way. The sketches it contained, made from just 1,679 digital bits, look cute to us today, very much of the ‘Pong’ video game generation.  Just before then, Nasa’s Pioneer 10 and 11 space probes each carried a metal calling card bolted onto their frame with symbols and drawings on the plaque, showing a naked man and woman.

Yet it’s possible that these kinds of message may turn out to be incomprehensible to aliens; they might find it as cryptic as we find Stone Age etchings.

Antique tech

“Linear drawings of a male and a female homo sapiens are legible to contemporary humans,” says Marek Kultys, a London-based science communications designer. ”But the interceptors of Pioneer 10 could well assume we are made of several separate body parts (i.e. faces, hair and the man’s chest drawn as a separate closed shapes) and our body surface is home for long worm-like beings (the single lines defining knees, abdomens or collarbones.).”

Man-made tech may also be an issue. The most basic requirement for understanding Voyager’s Golden Record, launched 35 years ago and now way out beyond Pluto, is a record player. Aliens able to play it at 16 and 2/3 revolutions a minute will hear audio greetings in 55 world languages, including a message of ‘Peace and Friendship’ from former United Nations Secretary General Kurt Waldheim. But how many Earthlings today have record players, let alone extraterrestrials?
(Nasa)
Our sights and sounds of Earth might be unintelligible to an alien audience (Nasa)



Time capsule

Inevitably such messages become outdated too, like time capsules. Consider the case of the Oglethorpe Atlanta Crypt of Civilization – a time capsule sealed on Earth in 1940, complete with a dry martini and a poster of Gone With the Wind. It was intended as a snapshot of 20th Century life for future humans, not aliens, but like an intergalactic message, may only give a limited picture to future generations. When, in 61,000 years, the Oglethorpe time capsule is opened, would Gone With The Wind have stood the test of time?


(Nasa)
This message was taken into the stars by Pioneer - but we have no idea if aliens would be able to understand it (Nasa)

Kultys argues that all these factors should be taken into account when we calculate the likelihood of communicating with intelligent life. The astronomer Frank Drake’s famous equation allows anyone to calculate how many alien species are, based on likely values of seven different factors. At a UK Royal Society meeting in 2010 Drake estimated there are roughly 10,000 detectable civilisations in the galaxy. Yet Kultys points out that we should also factor in how many aliens are using the same channel of communications as us, are as willing to contact us as we are them, whose language we hope to learn, and who are physically similar to us.

Another barrier we might consider is the long distance nature of trans-cosmos communication. It means that many years ‒ even a thousand ‒ could pass between sending a message and receiving a reply. Paterson sees romance in that. “Our hope for communication with another intelligent civilisation has a melancholic aspect to it. 
We are on an island in a vast, dark space. Imagine if communication… became like an exchange of perfumed love letters with the quiet agony of expectation... Will we meet? Will we be as the other imagined? Will the other be able to understand us?”

Ready for an answer?

Anthropologist John Traphagan of the University of Texas in Austin has been asking the same question, though his view is more cautious. "When it comes to ET, you'll get a signal of some kind; not much information and very long periods between ‘Hi, how are you?’ and whatever comes back. We may just shrug our shoulders and say 'This is boring’, and soon forget about it or, if the time lag wasn't too long, we might use the minimal information we get from our slow-speed conversation to invent what we think they're like and invent a kind concept of what they're after.”

(20th Century Fox)
The aliens in Independence Day (1996) did not come in peace (20th Century Fox)
While we have been sending out messages, we have not been preparing the planet for what happens when we get an interstellar return call. First contact could cause global panic. We might assume those answering are bent on galactic domination or, perhaps less likely, that they are peaceful when in fact they’re nasty.

Consider how easy it is to mess up human-to-human communications; I got Traphagan’s first name wrong when I e-mailed him for this article. An apology within minutes cleared up the confusion, yet if he had been an alien anthropologist on some distant planet it would have taken much longer to fix. He later confessed: "I could have thought this is a snooty English journalist and our conversation might never have happened."

Even if Earth’s interstellar messaging committees weeded out the typos, cultural gaffes are always a possibility. These can only be avoided by understanding the alien’s culture – something that’s not easy to do, especially when you’ve never met those you’re communicating with.

Rosy picture

So, what is the best way to communicate? This is still up for grabs – perhaps it’s via smell, or some other technique we haven’t discovered yet. Clearly, creating a message that is timeless, free of cultural bias and universally comprehensible would be no mean feat.


But for starters, being honest about who we are is important if we want to have an extra-terrestrial dialogue lasting centuries, says Douglas Vakoch, director of interstellar message composition at Seti. (Otherwise, intelligent civilisations who’ve decoded our radio and TV signals might smell a rat.)

(Nasa)
The golden discs aboard the Voyager spacecraft require aliens to understand how to play a record (Nasa)

“Let's not try to hide our shortcomings,” says Vakoch. “The message we should send to another world is straightforward: We are a young civilisation, in the throes of our technological adolescence. We're facing a lot of problems here on Earth, and we're not even sure that we'll be around as a species when their reply comes in. But in spite of all of these challenges, we humans also have hope – especially hope in ourselves."


Yet ultimately what matters, says Paterson, is that they stop and consider the beings who sent them a message; the people who wanted to say: “Here are some important things. Here’s our DNA, here is some maths and universal physics. And here is our longing and desire to say “I’m like you, but I’m different.”

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