Tag: didn (page 4 of 12)

UK Scientists: Aliens May Have Sent Space Seeds To Create Life On Earth

February 21, 2015 / / 0 Comments

Excerpt from huffingtonpost.comScientists in the U.K. have examined a tiny metal circular object, and are suggesting it might be a micro-organism deliberately sent by extraterrestrials to create life on Earth.Don't be fooled by the size of the objec...

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Why science is so hard to believe?

February 19, 2015 / / 0 Comments

 
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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Stephen Hawking warns that attempting to contact aliens could invite disaster

February 13, 2015 / / 0 Comments

Excerpt from cambridge-news.co.ukWhat is known as Active Seti will be under serious discussion this week at the annual meeting of the American Association for the Advancement of Science (AAAS) in San Jose, California. Seti spokesman Dr Seth...

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Planck telescope puts new datestamp on first stars

February 10, 2015 / / 0 Comments


Polarisation of the sky
Planck has mapped the delicate polarisation of the CMB across the entire sky



Excerpt from bbc.com

Scientists working on Europe's Planck satellite say the first stars lit up the Universe later than previously thought.

The team has made the most precise map of the "oldest light" in the cosmos.

Earlier observations of this radiation had suggested the first generation of stars were bursting into life by about 420 million years after the Big Bang.

Planck's data indicates this great ignition was well established by some 560 million years after it all began.

"This difference of 140 million years might not seem that significant in the context of the 13.8-billion-year history of the cosmos, but proportionately it's actually a very big change in our understanding of how certain key events progressed at the earliest epochs," said Prof George Efstathiou, one of the leaders of the Planck Science Collaboration.

Subtle signal

The assessment is based on studies of the "afterglow" of the Big Bang, the ancient light called the Cosmic Microwave Background (CMB), which still washes over the Earth today.
Prof George Efstathiou: "We don't need more complicated explanations"

The European Space Agency's (Esa) Planck satellite mapped this "fossil" between 2009 and 2013.

It contains a wealth of information about early conditions in the Universe, and can even be used to work out its age, shape and do an inventory of its contents.

Scientists can also probe it for very subtle "distortions" that tell them about any interactions the CMB has had on its way to us.

Forging elements

One of these would have been imprinted when the infant cosmos underwent a major environmental change known as re-ionisation.

Prof Richard McMahon: "The two sides of the bridge now join"
It is when the cooling neutral hydrogen gas that dominated the Universe in the aftermath of the Big Bang was then re-energised by the ignition of the first stars.

These hot giants would have burnt brilliant but brief lives, producing the very first heavy elements. But they would also have "fried" the neutral gas around them - ripping electrons off the hydrogen protons.

And it is the passage of the CMB through this maze of electrons and protons that would have resulted in it picking up a subtle polarisation.

ImpressionImpression: The first stars would have been unwieldy behemoths that burnt brief but brilliant lives


The Planck team has now analysed this polarisation in fine detail and determined it to have been generated at 560 million years after the Big Bang.

The American satellite WMAP, which operated in the 2000s, made the previous best estimate for the peak of re-ionisation at 420 million years. 

The problem with that number was that it sat at odds with Hubble Space Telescope observations of the early Universe.

Hubble could not find stars and galaxies in sufficient numbers to deliver the scale of environmental change at the time when WMAP suggested it was occurring.

Planck's new timing "effectively solves the conflict," commented Prof Richard McMahon from Cambridge University, UK.

"We had two groups of astronomers who were basically working on different sides of the problem. The Planck people came at it from the Big Bang side, while those of us who work on galaxies came at it from the 'now side'. 

"It's like a bridge being built over a river. The two sides do now join where previously we had a gap," he told BBC News.

That gap had prompted scientists to invoke complicated scenarios to initiate re-ionisation, including the possibility that there might have been an even earlier population of giant stars or energetic black holes. Such solutions are no longer needed.

No-one knows the exact timing of the very first individual stars. All Planck does is tell us when large numbers of these stars had gathered into galaxies of sufficient strength to alter the cosmic environment. 

By definition, this puts the ignition of the "founding stars" well before 560 million years after the Big Bang. Quite how far back in time, though, is uncertain. Perhaps, it was as early as 200 million years. It will be the job of the next generation of observatories like Hubble's successor, the James Webb Space Telescope, to try to find the answer.

JWSTBeing built now: The James Webb telescope will conduct a survey of the first galaxies and their stars
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The history of the Universe

Graphic of the history of time
  • Planck's CMB studies indicate the Big Bang was 13.8bn years ago
  • The CMB itself can be thought of as the 'afterglow' of the Big Bang
  • It spreads across the cosmos some 380,000 years after the Big Bang
  • This is when the conditions cool to make neutral hydrogen atoms
  • The period before the first stars is often called the 'Dark Ages'
  • When the first stars ignite, they 'fry' the neutral gas around them
  • These giants also forge the first heavy elements in big explosions
  • 'First Light', or 'Cosmic Renaissance', is a key epoch in history
line

The new Planck result is contained in a raft of new papers just posted on the Esa website. 

These papers accompany the latest data release from the satellite that can now be used by the wider scientific community, not just collaboration members.
Dr Andrew Jaffe: "The simplest models for inflation are ruled out"
Two years ago, the data dump largely concerned interpretations of the CMB based on its temperature profile. It is the CMB's polarisation features that take centre-stage this time.
It was hoped that Planck might find direct evidence in the CMB's polarisation for inflation - the super-rapid expansion of space thought to have occurred just fractions of a second after the Big Bang. This has not been possible. But all the Planck data - temperature and polarisation information - is consistent with that theory, and the precision measurements mean new, tighter constraints have been put on the likely scale of the inflation signal, which other experiments continue to chase.
What is clear from the Planck investigation is that the simplest models for how the super-rapid expansion might have worked are probably no longer tenable, suggesting some exotic physics will eventually be needed to explain it.
"We're now being pushed into a parameter space we didn't expect to be in," said collaboration scientist Dr Andrew Jaffe from Imperial College, UK. "That's OK. We like interesting physics; that's why we're physicists, so there's no problem with that. It's just we had this naïve expectation that the simplest answer would be right, and sometimes it just isn't."

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Scientists discover organism that hasn’t evolved in more than 2 billion years

February 4, 2015 / / 0 Comments



Nonevolving bacteria
These sulfur bacteria haven't evolved for billions of years.
Credit: UCLA Center for the Study of Evolution and the Origin of Life

Excerpt from natmonitor.com
By Justin Beach

If there was a Guinness World Record for not evolving, it would be held by a sulfur-cycling microorganism found off the course of Australia. According to research published in the Proceedings of the National Academy of Sciences, they have not evolved in any way in more than two billion years and have survived five mass extinction events.
According to the researchers behind the paper, the lack of evolution actually supports Charles Darwin’s theory of evolution by natural selection.
The researchers examined the microorganisms, which are too small to see with the naked eye, in samples of rocks from the coastal waters of Western Australia. Next they examined samples of the same bacteria from the same region in rocks 2.3 billion years old. Both sets of bacteria are indistinguishable from modern sulfur bacteria found off the coast of Chile.



“It seems astounding that life has not evolved for more than 2 billion years — nearly half the history of the Earth. Given that evolution is a fact, this lack of evolution needs to be explained,” said J. William Schopf, a UCLA professor of earth, planetary and space sciences in the UCLA College who was the study’s lead author in a statement.
Critics of Darwin’s theory of evolution might be tempted to jump on this discovery as proof that Darwin was wrong, but that would be a mistake.
Darwin’s work focused more on species that changed, rather than species that didn’t. However, there is nothing in Darwin’s work that states that a successful species that has found it’s niche in an ecosystem has to change. Unless there is change in the ecosystem or competition for resources there would be no reason for change.
“The rule of biology is not to evolve unless the physical or biological environment changes, which is consistent with Darwin. These microorganisms are well-adapted to their simple, very stable physical and biological environment. If they were in an environment that did not change but they nevertheless evolved, that would have shown that our understanding of Darwinian evolution was seriously flawed.” said Schopf, who also is director of UCLA’s Center for the Study of Evolution and the Origin of Life.
It is likely that there were genetic mutations in the organisms. Mutations are fairly random and happen in all species, but unless those mutations are improvements that help the species function better in the environment, they usually do not get passed on.
Schopf said that the findings provide further proof that Darwin’s ideas were right.
The oldest fossils analyzed for the study date back to the Great Oxidation Event. This event, which occurred between 2.2 and 2.4 billion years ago, saw a substantial increase in Earth’s oxygen levels. That period also saw an increase in sulfates and nitrates, which is all that the microorganisms would have needed to survive and reproduce.
Shopf and his team used Raman spectroscopy, which allows scientists to examine the composition and chemistry of rocks as well as confocal laser scary microscopy to generate 3-D images of fossils embedded in rock.
The research was funded by NASA Astrobiology Institute, in the hope that it will help the space agency to find life elsewhere.

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How 40,000 Tons of Cosmic Dust Falling to Earth Affects You and Me

January 28, 2015 / / 0 Comments


Picture of The giant star Zeta Ophiuchi is having a "shocking" effect on the surrounding dust clouds in this infrared image from NASA's Spitzer Space Telescope
In this infrared image, stellar winds from a giant star cause interstellar dust to form ripples. There's a whole lot of dust—which contains oxygen, carbon, iron, nickel, and all the other elements—out there, and eventually some of it finds its way into our bodies.
Photograph by NASA, JPL-Caltech

We have stardust in us as old as the universe—and some that may have landed on Earth just a hundred years ago.

Excerpt from National Geographic
By Simon Worrall

Astrophysics and medical pathology don't, at first sight, appear to have much in common. What do sunspots have to do with liver spots? How does the big bang connect with cystic fibrosis?
Book jacket courtesy of schrijver+schrijver

Astrophysicist Karel Schrijver, a senior fellow at the Lockheed Martin Solar and Astrophysics Laboratory, and his wife, Iris Schrijver, professor of pathology at Stanford University, have joined the dots in a new book, Living With the Stars: How the Human Body Is Connected to the Life Cycles of the Earth, the Planets, and the Stars.

Talking from their home in Palo Alto, California, they explain how everything in us originated in cosmic explosions billions of years ago, how our bodies are in a constant state of decay and regeneration, and why singer Joni Mitchell was right.

"We are stardust," Joni Mitchell famously sang in "Woodstock." It turns out she was right, wasn't she?

Iris: Was she ever! Everything we are and everything in the universe and on Earth originated from stardust, and it continually floats through us even today. It directly connects us to the universe, rebuilding our bodies over and again over our lifetimes.

That was one of the biggest surprises for us in this book. We really didn't realize how impermanent we are, and that our bodies are made of remnants of stars and massive explosions in the galaxies. All the material in our bodies originates with that residual stardust, and it finds its way into plants, and from there into the nutrients that we need for everything we do—think, move, grow. And every few years the bulk of our bodies are newly created.

Can you give me some examples of how stardust formed us?

Karel: When the universe started, there was just hydrogen and a little helium and very little of anything else. Helium is not in our bodies. Hydrogen is, but that's not the bulk of our weight. Stars are like nuclear reactors. They take a fuel and convert it to something else. Hydrogen is formed into helium, and helium is built into carbon, nitrogen and oxygen, iron and sulfur—everything we're made of. When stars get to the end of their lives, they swell up and fall together again, throwing off their outer layers. If a star is heavy enough, it will explode in a supernova.

So most of the material that we're made of comes out of dying stars, or stars that died in explosions. And those stellar explosions continue. We have stuff in us as old as the universe, and then some stuff that landed here maybe only a hundred years ago. And all of that mixes in our bodies.

Picture of the remnants of a star that exploded in a supernova
Stars are being born and stars are dying in this infrared snapshot of the heavens. You and I—we come from stardust.
Photograph by NASA, JPL-Caltech, University of Wisconsin


Your book yokes together two seemingly different sciences: astrophysics and human biology. Describe your individual professions and how you combined them to create this book.

Iris: I'm a physician specializing in genetics and pathology. Pathologists are the medical specialists who diagnose diseases and their causes. We also study the responses of the body to such diseases and to the treatment given. I do this at the level of the DNA, so at Stanford University I direct the diagnostic molecular pathology laboratory. I also provide patient care by diagnosing inherited diseases and also cancers, and by following therapy responses in those cancer patients based on changes that we can detect in their DNA.

Our book is based on many conversations that Karel and I had, in which we talked to each other about topics from our daily professional lives. Those areas are quite different. I look at the code of life. He's an astrophysicist who explores the secrets of the stars. But the more we followed up on our questions to each other, the more we discovered our fields have a lot more connections than we thought possible.

Karel: I'm an astrophysicist. Astrophysicists specialize in all sorts of things, from dark matter to galaxies. I picked stars because they fascinated me. But no matter how many stars you look at, you can never see any detail. They're all tiny points in the sky.

So I turned my attention to the sun, which is the only star where we can see what happens all over the universe. At some point NASA asked me to lead a summer school for beginning researchers to try to create materials to understand the things that go all the way from the sun to the Earth. I learned so many things about these connections I started to tell Iris. At some point I thought: This could be an interesting story, and it dawned on us that together we go all the way, as she said, from the smallest to the largest. And we have great fun doing this together.

We tend to think of our bodies changing only slowly once we reach adulthood. So I was fascinated to discover that, in fact, we're changing all the time and constantly rebuilding ourselves. Talk about our skin.

Iris: Most people don't even think of the skin as an organ. In fact, it's our largest one. To keep alive, our cells have to divide and grow. We're aware of that because we see children grow. But cells also age and eventually die, and the skin is a great example of this.
It's something that touches everything around us. It's also very exposed to damage and needs to constantly regenerate. It weighs around eight pounds [four kilograms] and is composed of several layers. These layers age quickly, especially the outer layer, the dermis. The cells there are replaced roughly every month or two. That means we lose approximately 30,000 cells every minute throughout our lives, and our entire external surface layer is replaced about once a year.

Very little of our physical bodies lasts for more than a few years. Of course, that's at odds with how we perceive ourselves when we look into the mirror. But we're not fixed at all. We're more like a pattern or a process. And it was the transience of the body and the flow of energy and matter needed to counter that impermanence that led us to explore our interconnectedness with the universe.

You have a fascinating discussion about age. Describe how different parts of the human body age at different speeds.

Iris: Every tissue recreates itself, but they all do it at a different rate. We know through carbon dating that cells in the adult human body have an average age of seven to ten years. That's far less than the age of the average human, but there are remarkable differences in these ages. Some cells literally exist for a few days. Those are the ones that touch the surface. The skin is a great example, but also the surfaces of our lungs and the digestive tract. The muscle cells of the heart, an organ we consider to be very permanent, typically continue to function for more than a decade. But if you look at a person who's 50, about half of their heart cells will have been replaced.

Our bodies are never static. We're dynamic beings, and we have to be dynamic to remain alive. This is not just true for us humans. It's true for all living things.

A figure that jumped out at me is that 40,000 tons of cosmic dust fall on Earth every year. Where does it all come from? How does it affect us?

Karel: When the solar system formed, it started to freeze gas into ice and dust particles. They would grow and grow by colliding. Eventually gravity pulled them together to form planets. The planets are like big vacuum cleaners, sucking in everything around them. But they didn't complete the job. There's still an awful lot of dust floating around.

When we say that as an astronomer, we can mean anything from objects weighing micrograms, which you wouldn't even see unless you had a microscope, to things that weigh many tons, like comets. All that stuff is still there, being pulled around by the gravity of the planets and the sun. The Earth can't avoid running into this debris, so that dust falls onto the Earth all the time and has from the very beginning. It's why the planet was made in the first place. 

Nowadays, you don't even notice it. But eventually all that stuff, which contains oxygen and carbon, iron, nickel, and all the other elements, finds its way into our bodies.

When a really big piece of dust, like a giant comet or asteroid, falls onto the Earth, you get a massive explosion, which is one of the reasons we believe the dinosaurs became extinct some 70 million years ago. That fortunately doesn't happen very often. But things fall out of the sky all the time. [Laughs]

Many everyday commodities we use also began their existence in outer space. Tell us about salt.

Karel: Whatever you mention, its history began in outer space. Take salt. What we usually mean by salt is kitchen salt. It has two chemicals, sodium and chloride. Where did they come from? They were formed inside stars that exploded billions of years ago and at some point found their way onto the Earth. Stellar explosions are still going on today in the galaxy, so some of the chlorine we're eating in salt was made only recently.

You study pathology, Iris. Is physical malfunction part of the cosmic order?

Iris: Absolutely. There are healthy processes, such as growth, for which we need cell division. Then there are processes when things go wrong. We age because we lose the balance between cell deaths and regeneration. That's what we see in the mirror when we age over time. That's also what we see when diseases develop, such as cancers. Cancer is basically a mistake in the DNA, and because of that the whole system can be derailed. Aging and cancer are actually very similar processes. They both originate in the fact that there's a loss of balance between regeneration and cell loss.

Cystic fibrosis is an inherited genetic disease. You inherit an error in the DNA. Because of that, certain tissues do not have the capability to provide their normal function to the body. My work is focused on finding changes in DNA in different populations so we can understand better what kinds of mutations are the basis of that disease. Based on that, we can provide prognosis. There are now drugs that target specific mutations, as well as transplants, so these patients can have a much better life span than was possible 10 or 20 years ago.

How has writing this book changed your view of life—and your view of each other?

Karel: There are two things that struck me, one that I had no idea about. The first is what Iris described earlier—the impermanence of our bodies. As a physicist, I thought the body was built early on, that it would grow and be stable. Iris showed me, over a long series of dinner discussions, that that's not the way it works. Cells die and rebuild all the time. We're literally not what were a few years ago, and not just because of the way we think. Everything around us does this. Nature is not outside us. We are nature.

As far as our relationship is concerned, I always had a great deal of respect for Iris, and physicians in general. They have to know things that I couldn't possibly remember. And that's only grown with time.

Iris: Physics was not my favorite topic in high school. [Laughs] Through Karel and our conversations, I feel that the universe and the world around us has become much more accessible. That was our goal with the book as well. We wanted it to be accessible and understandable for anyone with a high school education. It was a challenge to write it that way, to explain things to each other in lay terms. But it has certainly changed my view of life. It's increased my sense of wonder and appreciation of life.

In terms of Karel's profession and our relationship, it has inevitably deepened. We understand much better what the other person is doing in the sandboxes we respectively play in. [Laughs]

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Mysterious radio signal from space caught live for first time

January 28, 2015 / / 0 Comments




Excerpt from foxnews.com

Astronomers in Australia have picked up an “alien” radio signal from space for the first time as it occurred. The signal, or radio “burst”, was discovered on May 15, 2014, though it’s just being reported by the Monthly Notices of the Royal Astronomical Society. “The burst was identified within 10 seconds of its occurrence,” said Emily Petroff, a doctoral student from Melbourne’s Swinburne University of Technology. “The importance of the discovery was recognized very quickly and we were all working very excitedly to contact other astronomers and telescopes around the world to look at the location of the burst.”
Emerging from an unknown source, these bursts are bright flashes of radio waves that emit as much energy in a few milliseconds as the sun does in 24 hours.  “The first fast radio burst was discovered in 2007,” Petroff tells FoxNews.com, “and up until our discovery there were 8 more found in old or archival data.” While researchers use telescopes in Hawaii, India, Germany, Chile, California, and the California Islands to search for bursts, it is the CSIRO Parkes radio telescope in Eastern Australia that is the first to catch one as its happening.
The cause of these mysterious signals remains unknown, with possible theories ranging from black holes to alien communication. However, UFO hunters shouldn’t get too excited. According to Petroff, “We're confident that they're coming from natural sources, that is to say it's probably not aliens, but we haven't solved the case completely. The two most promising theories at the moment are that these bursts could be produced either by a star producing a highly energetic flare, or from a neutron star collapsing to make a black hole. Both of these things would be from sources in far-away galaxies just reaching us from billions of light years away.”
Catching the bursts as they happen is key to finding the source, and though Petroff’s team scrambled upon making their discovery, they didn’t move fast enough to find the afterglow and pin down the cause. “Finding one in real-time has been the goal for a while because we would then be able to act on it and mobilize other telescopes to look that way,” Petroff says. “We did this in the case of this real-time discovery, but we didn't get on the target until about eight hours later with other telescopes, at which time nothing was found.” However, they were able to eliminate a few possible causes, such as gamma-ray bursts from exploding stars and supernovae. Also, the team was able to determine that the source had been near an object with a sizeable magnetic field from the way the wavelengths were polarized.
While the source of the fast radio burst remains a mystery, the team remains hopeful that they can learn from their mistakes and one day solve the case. “All we can do is learn from our experience with this discovery and create a more efficient system for next time,” Petroff says. “We still spend a large amount of time looking for fast radio bursts with the Parkes telescope and the next time we are in the right place at just the right time, we'll be able to act faster than ever before and hopefully solve the mystery once and for all!”

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The Weirdest, Coolest Stuff We’ve Learned About Rosetta’s Comet So Far

January 28, 2015 / / 0 Comments


Various features on a smooth part of the comet's surface in the region named Imhotep.


Excerpt from wired.com

The Rosetta spacecraft has been studying comet 67P/Churyumov-Gerasimenko up close since August, collecting data of unprecedented detail and taking pictures of a starkly beautiful comet-scape. While the Philae lander has enjoyed much of the spotlight—partly thanks to its now-famous triple landing—Rosetta has been making plenty of its own discoveries.  

One of the biggest came last month, when scientists found that the chemical signature of the comet’s water is nothing like that on Earth, contradicting the theory that crashing comets supplied our planet with water. Comet 67P belongs to the Jupiter family of comets, and the findings also imply that these kinds of comets were formed at a wider range of distances from the sun than previously thought, says Michael A’Hearn, a planetary scientist at the University of Maryland, College Park, and member of the Rosetta science team.  

Today, scientists have published the first big set of results from Rosetta in a slew of papers in the journal Science. The results include measurements and analyses of the comet’s shape, structure, surface, and the surrounding dust and gas particles. Here are just a few of the amazing things they’ve discovered about Rosetta’s comet so far: 

The surface is fantastically weird  

The comet has quite the textured landscape, covered with steep cliffs, boulders, weird bumps, cracks, pits, and smooth terrain. There are fractures of all sizes, including one that’s several yards wide and stretches for more than half a mile along the comet’s neck. Researchers don’t yet know what caused these cracks.  The pits have steep sides and flat bottoms, ranging in size from a few tens to hundreds of feet wide. Jets of dust shoot out from some of the pits, suggesting that the ejection of material formed these features.  Another strange feature is what scientists are calling goosebumps—weird bumpy patches found particularly on steep slopes.

While other features such as pits and fractures range in sizes, all of the goosebumps are about 10 feet wide. No one knows what kind of process would make the bumps, but whatever it is could have played an important part in the comet’s formation. It may be breezy  Rosetta spotted dune- and ripple-like patterns,wind tails behind rocks, and even moats surrounding rocks, suggesting that a light breeze may blow dust along the surface. Such a gentle wind would have to come from gases leaking from below.

Because of the extremely low gravity on the comet, it wouldn’t take a strong gust to blow things around. It may have formed from two separate pieces  Or not. The most distinct feature of comet 67P is its odd, two-lobed shape, which resembles a duck. Although scientists have seen this lobed structure in other comets before, namely Borrelly and Hartley 2, none are as pronounced as comet 67P’s. Borrelly and Hartley 2 look more like elongated potatoes while 67P has a clearly defined head and body. The strange shape suggests the comet was once two separate pieces called cometesimals—what are now the duck’s head and body—that stuck together. 

The other possibility is that erosion ate away the parts around the neck. Preliminary evidence points to the first hypothesis.

“Probably most of us on the OSIRIS team lean toward thinking it was two cometesimals,” A’Hearn said. (OSIRIS is one of Rosetta’s imaging instruments.) But the scientists won’t have conclusive evidence until they study the comet in more detail. For example, they now see layering along the neck—if erosion carved out the comet’s duck shape, they should find the same same layering pattern continuing onto the other side of the neck. 

Black, with a tinge of red  

Even Rosetta’s color pictures show a grayish comet, but if you were to see it in person, you would see a pitch-black chunk of dust and ice, as it reflects only six percent of incoming light. By comparison, the moon reflects 12 percent of incoming light and Earth reflects 31 percent. But comet 67P’s not completely black, as it has a hint of red. Water, water, nowhere?  The comet’s covered in opaque, organic compounds. Although comet 67P is undoubtedly icy, it hardly shows any water ice on its surface at all. 

Which isn’t too surprising, as comets Tempel 1 and Hartley 2 didn’t have much ice on their surfaces either, A’Hearn says. Rosetta has yet to see sunlight reach every side of the comet yet, so there may still be some icy patches hidden from view.  But, researchers do see the comet spraying water vapor into space, which means water ice likely lies just beneath the surface. The ice doesn’t have to be more than a centimeter deep to be invisible from the infrared instruments that detect the ice. Indeed, the data from Philae’s first bounce suggested that there’s a hard layer of ice beneath 4 to 8 inches of dust. 

This duck floats  

If you could find a big enough pond, that is. Like other known comets, the density of comet 67P is about half that of water ice. Initial measurements reveal that it’s also very porous—as much as 80 percent of it may be empty space. Rosetta has found depressions, which may have formed when the surface collapsed over particularly porous material underneath. 

Different from every angle

As the comet nears the sun, it heats up, and ices and other volatile chemicals sublimate, spraying gases into space. So far, the most prominent gases that have been ejected are water vapor, carbon dioxide, and carbon monoxide. They spew out in different amounts from different parts of the comet. In particular, a lot of the water has been observed gushing out from the neck.

The comet will continue to get more active as it reaches its closest approach to the sun in mid-August. It will burst with stronger jets of gas and dust, and maybe even blast off chunks of itself. If the comet is this interesting now, A’Hearn says, just wait until it gets to its nearest point to the sun, when it’s just 1.29 times farther from the sun than Earth is.

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The Mystery of the Ghost Ship Lunatic

January 27, 2015 / / 0 Comments

The Lunatic Piran found abandoned Jure Stwerk at the Helm           ...

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With innovators from around the globe digging in, public moon travel may be only 20 years away

January 26, 2015 / / 0 Comments



moon
Image Credit: hkeita/Shutterstock


Excerpt from  venturebeat.com
By Vivek Wadhwa

Five teams competing for the $30 million Google Lunar XPRIZE have just been awarded a combined $5.25 million for meeting significant milestones in developing a robot that can safely land on the surface of the moon, travel 500 meters over the lunar surface, and send mooncasts back to the Earth. A tiny startup from India, Team Indus, with no experience in robotics or space flight just won $1 million of this prize. It stood head to head with companies that had been funded by billionaires, had received the assistance of NASA, and had the support of leading universities.
The good news is that governments no longer have a monopoly on space exploration. In two or three decades, we will have entrepreneurs taking us on private spaceflights to the moon. That is what has become possible.

What has changed since the days of the Apollo moon landings is that the cost of building technologies has dropped exponentially. What cost billions of dollars then costs millions now, and sometimes even less. Our smartphones have computers that are more powerful than the Cray supercomputers of yesteryear — which had strict export controls and cost tens of millions of dollars. We carry high-definition cameras in our pockets that are more powerful than those on NASA spacecraft. The cameras in the Mars Curiosity Rover, for example, have a resolution of 2 megapixels with 8GB of flash memory, the same as our clunky first-generation iPhones. The Apollo Guidance Computer, which took humans to the moon in 1966, had a 2.048 MHz processor — slower than those you find in calculators and musical greeting cards.

The same technologies as are available in the United States and Europe are available worldwide. Innovation has globalized.
I met Team Indus while I was in Mumbai to speak at INK last November. When they told me they were competing for the Google Lunar XPRIZE. I didn’t take them seriously because I had seen their counterpart in Silicon Valley, Moon Express, which has the support of tech moguls such as Naveen Jain. How could a scrawny little startup in Bangalore take on Naveen Jain, former NASA engineer Bob Richards, and NASA itself, I thought. The Moon Express team is a force of nature, has the advantage of being on the NASA Ames Research campus, and has been given R&D worth billions of dollars by NASA.

Team Indus was also up against Astrobotic, which is a spinoff from the Carnegie Mellon University Robotics Institute, and Israel-based SpaceIL, which has the backing of the country’s top research institutes.

The company’s win blew my mind. Even though the subject of my INK talk was how Indian entrepreneurs could help change the world, I didn’t think it was already happening.

(See my Jan. 1 story on the Indian tech scene and watch this talk to learn more: Why India shouldn’t be succeeding but is.)

The Bangalore-based startup was founded by former I.T. executive Rahul Narayan and four of his friends: an Air Force pilot, a marketing executive, an investment banker, and an aerospace engineer. None of the team had experience in building spacecraft or robots, yet they were able to build technology that could navigate to the moon.

Narayan says he expects completion of his space mission to cost around $30 million. Moon Express chief executive Bob Richards estimates $50 million. These numbers are higher than the $20 million prize that they hope to win. But both see far greater opportunities: They hope to be pioneers in what could be a trillion-dollar industry. Richards is looking to mine the moon for minerals and bring them back to Earth. Each payload could be worth billions.

The Google Lunar XPRIZE has 26 teams competing from around the world. Collectively, they will spend in the hundreds of millions of dollars on their efforts. For them, it is not all about winning the contest; many of the losers will still commercialize their space technologies or put their knowledge to use in other fields. This is the power of such competitions. They lead entrants to spend multiples of the offered purse on innovative solutions. And they motivate people outside the industry, such as Narayan, to enter it with out-of-the-box thinking.

Innovation prizes are not new. In fact, a number of celebrated historical feats were made possible, in part, by the desire to win these prizes. In the 1920s, New York hotel owner Raymond Orteig offered a $25,000 prize to the first person to fly non-stop between New York and Paris. Several unsuccessful attempts were made before an American airmail pilot named Charles Lindbergh won the competition in 1927 with his plane, The Spirit of St. Louis. 
Lindbergh’s achievement made him a national hero and a global celebrity. And it sparked the interest and investment that led to the modern aviation industry.

That is what I expect will come of the Lunar XPRIZE. And that is why I am looking forward to booking my round-trip ticket to the moon one summer in the 2030s.

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Spacecraft found on Mars – and it’s ours

January 21, 2015 / / 0 Comments




Computer image of the Beagle 2


Excerpt from skyandtelescope.com
By Kelly Beatty  


On December 25, 2003, a British-built lander dropped to the Martian surface and disappeared without a trace. Now we know what happened to it.  It's hard to overstate how valuable the main camera aboard the Mars Reconnaissance Orbiter has been. The craft's High-Resolution Imaging Science Experiment, or HiRISE, uses a 20-inch (0.5-m) f/24 telescope to record details on the Martian surface as small as 0.3 m (about 10 inches). 

Beagle 2 seen from orbit by HiRISE
An overhead view of Beagle 2's landing site on Isidis Planitia shows a bright reflection from the long-lost spacecraft. Apparently it landed safely on December 25, 2003, and had begun to operate when it failed. NASA's Mars Reconnaissance Orbiter recorded this image on December 15, 2014. NASA / JPL / Univ. of Arizona / Univ. of Leicester - See more at: http://www.skyandtelescope.com/astronomy-news/beagle-2-lander-found-on-mars-01192015/#sthash.5KSZ8V6W.dpuf


Primarily it's a powerful tool for studying Martian geology at the smallest scales, and NASA scientists sometimes use it to track the progress (and even the arrivals) of their rovers. Beagle 2 on Mars  The clamshell-like Beagle 2 lander weighed just 30 kg, but it was well equipped to study Martian rocks and dust — and even to search for life. Beagle 2 consortium  But the HiRISE team has also been on a years-long quest to find the remains of Beagle 2, a small lander that had hitchhiked to the Red Planet with the European Space Agency's Mars Express orbiter. It descended to the Martian surface on Christmas Day in 2003 and was never heard from again. Space aficionados have debated its fate ever since. Did parachute failure lead to a crash landing? Did strong surface winds flip the saucer-shaped craft upside down? Did the Martians take it hostage?  Now, thanks to HiRISE, we know more of the story.  
An overhead view of Beagle 2's landing site on Isidis Planitia shows a bright reflection from the long-lost spacecraft. Apparently it landed safely on December 25, 2003, and had begun to operate when it failed. NASA's Mars Reconnaissance Orbiter recorded this image on December 15, 2014. NASA / JPL / Univ. of Arizona / Univ. of Leicester 


Images taken in February 2013 and June 2014 of the landing area in Isidis Planitia showed promising blips near the edge of each frame. A follow-up color view, acquired on December 15th and released three days ago, show a bright spot consistent with Beagle 2. The fully-opened lander would have been less than 2 m (6½ feet) across, so the craft is only barely resolved. Apparently the spacecraft made it to the surface intact, opened its clamshell cover, and had partially deployed its four petal-shaped solar-cell panels before something went awry. Beagle 2 seen from orbit by HiRISE  

One encouraging clue is that the bright reflection changes position slightly from image to image, consistent with sunlight reflecting off different lander panels. Two other unusual spots a few hundred meters away appears to be the lander's parachute and part of the cover that served as a shield during the 5½-km-per-second atmospheric descent...


On December 25, 2003, a British-built lander dropped to the Martian surface and disappeared without a trace. Now we know what happened to it.
It's hard to overstate how valuable the main camera aboard the Mars Reconnaissance Orbiter has been. The craft's High-Resolution Imaging Science Experiment, or HiRISE, uses a 20-inch (0.5-m) f/24 telescope to record details on the Martian surface as small as 0.3 m (about 10 inches). Primarily it's a powerful tool for studying Martian geology at the smallest scales, and NASA scientists sometimes use it to track the progress (and even the arrivals) of their rovers.
Beagle 2 on Mars
The clamshell-like Beagle 2 lander weighed just 30 kg, but it was well equipped to study Martian rocks and dust — and even to search for life.
Beagle 2 consortium
But the HiRISE team has also been on a years-long quest to find the remains of Beagle 2, a small lander that had hitchhiked to the Red Planet with the European Space Agency's Mars Express orbiter. It descended to the Martian surface on Christmas Day in 2003 and was never heard from again. Space aficionados have debated its fate ever since. Did parachute failure lead to a crash landing? Did strong surface winds flip the saucer-shaped craft upside down? Did the Martians take it hostage?
Now, thanks to HiRISE, we know more of the story. Images taken in February 2013 and June 2014 of the landing area in Isidis Planitia showed promising blips near the edge of each frame. A follow-up color view, acquired on December 15th and released three days ago, show a bright spot consistent with Beagle 2. The fully-opened lander would have been less than 2 m (6½ feet) across, so the craft is only barely resolved. Apparently the spacecraft made it to the surface intact, opened its clamshell cover, and had partially deployed its four petal-shaped solar-cell panels before something went awry.
Beagle 2 seen from orbit by HiRISE
An overhead view of Beagle 2's landing site on Isidis Planitia shows a bright reflection from the long-lost spacecraft. Apparently it landed safely on December 25, 2003, and had begun to operate when it failed. NASA's Mars Reconnaissance Orbiter recorded this image on December 15, 2014.
NASA / JPL / Univ. of Arizona / Univ. of Leicester
One encouraging clue is that the bright reflection changes position slightly from image to image, consistent with sunlight reflecting off different lander panels. Two other unusual spots a few hundred meters away appears to be the lander's parachute and part of the cover that served as a shield during the 5½-km-per-second atmospheric descent.
The initial images didn't just show up. They'd been requested and searched by Michael Croon of Trier, Germany, who'd served on the Mars Express operations team. Croon had asked for specific camera targeting through a program called HiWish, through which anyone can submit suggestions for HiRISE images. Read more about this fascinating sleuthing story.
"Not knowing what happened to Beagle 2 remained a nagging worry," comments Rudolf Schmidt in an ESA press release about the find. "Understanding now that Beagle 2 made it all the way down to the surface is excellent news." Schmidt served as the Mars Express project manager at the time.
Built by a consortium of organizations, Beagle 2 was the United Kingdom's first interplanetary spacecraft. The 32-kg (73-pound) lander carried six instruments to study geochemical characteristics of the Martian surface and to test for the presence of life using assays of carbon isotopes. It was named for HMS Beagle, the ship that carried a crew of 73 (including Charles Darwin) on an epic voyage of discovery in 1831–36.
- See more at: http://www.skyandtelescope.com/astronomy-news/beagle-2-lander-found-on-mars-01192015/#sthash.5KSZ8V6W.dpuf

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CEO of Tesla Motors is trying to bring the Internet to space

January 19, 2015 / / 0 Comments

 Excerpt from cnet.com The SpaceX CEO wants to build a satellite network high above Earth that would speed up the Internet and bring access to underserved communities. And he'll use the profits to help colonize Mars.  Elon Musk, the man who...

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

January 16, 2015 / / 0 Comments




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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