Excerpt from cnet.com Google's Project Fi wireless service has the potential to turn the mobile industry on its head. But not in the way you might expect. Last week, Google announce...
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From today.com After a long week, there's nothing better than a healthy dose of cuteness. Inspired by the sweet moment when TODAY anchor Savannah Guthrie's baby,...
Reuters
With the right expertise in molecular biology, one could start a basic laboratory to modify human embryos using a genome-editing computer technique all for a couple thousand dollars, according to a new report.
Genetic modification has received heightened scrutiny recently following last week’s announcement that Chinese researchers had, for the first time, successfully edited human embryos’ genomes.
The team at Sun Yat-Sen University in Guangzhou, China, used CRISPR (clustered regularly interspaced palindromic repeats), a technique that relies on “cellular machinery” used by bacteria in defense against viruses.
This machinery is copied and altered to create specific gene-editing complexes, which include the wonder enzyme Cas9. The enzyme works its way into the DNA and can be used to alter the molecule from the inside. The combination is attached to an RNA guide that takes the gene-editing complex to its target, telling Cas9 where to operate.
Use of the CRISPR technique is not necessarily relegated to the likes of cash-flush university research operations, according to a report by Business Insider.
"You could conceivably set up a CRISPR lab for $2,000,” he said, according to Business Insider.
Other top researchers have echoed this sentiment.
"Any scientist with molecular biology skills and knowledge of how to work with [embryos] is going to be able to do this,” Jennifer Doudna, a biologist at the University of California, Berkeley, recently told MIT Tech Review, which reported that Doudna co-discovered how to edit genetic code using CRISPR in 2012.
Last week, the Sun Yat-Sen University research team said it attempted to cure a gene defect that causes beta-thalassemia (a genetic blood disorder that could lead to severe anemia, poor growth, skeletal abnormalities and even death) by editing the germ line. For that purpose they used a gene-editing technique based on injecting non-viable embryos with a complex, which consists of a protective DNA element obtained from bacteria and a specific protein.
"I suspect this week will go down as a pivotal moment in the history of medicine," wrote science journalist Carl Zimmer for National Geographic.
Response to the new research has been mixed. Some experts say the gene editing could help defeat genetic diseases even before birth. Others expressed concern.
“At present, the potential safety and efficacy issues arising from the use of this technology must be thoroughly investigated and understood before any attempts at human engineering are sanctioned, if ever, for clinical testing,” a group of scientists, including some who had worked to develop CRISPR, warned in Science magazine.
Meanwhile, the director of the US National Institutes for Health (NIH) said the agency would not fund such editing of human embryo genes.
“Research using genomic editing technologies can and are being funded by NIH,” Francis Collins said Wednesday. “However, NIH will not fund any use of gene-editing technologies in human embryos. The concept of altering the human germline in embryos for clinical purposes ... has been viewed almost universally as a line that should not be crossed.”
Although the discovery of CRISPR sequences dates back to 1987 – when it was first used to cure bacteria of viruses – its successes in higher animals and humans were only achieved in 2012-13, when scientists achieved a revolution by combining the resulting treatment system with Cas9 for the first time.
On April 17, the MIT’s Broad Institute announced that has been awarded the first-ever patent for working with the Crisp-Cas9 system.
The institute’s director, Eric Lander, sees the combination as “an extraordinary, powerful tool. The ability to edit a genome makes it possible to discover the biological mechanisms underlying human biology.”
The system’s advantage over other methods is in that it can also target several genes at the same time, working its way through tens of thousands of so-called 'guide' RNA sequences that lead them to the weapon to its DNA targets.
Meanwhile, last month in the UK, a healthy baby was born from an embryo screened for genetic diseases, using karyomapping, a breakthrough testing method that allows doctors to identify about 60 debilitating hereditary disorders.
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The Hooker 100-inch reflecting telescope at the Mount Wilson Observatory, just outside Los Angeles. Edwin Hubble's chair, on an elevating platform, is visible at left. A view from this scope first told Hubble our galaxy isn't the only one. Courtesy of The Observatories of the Carnegie Institution for Science Collection at the Huntington Library, San Marino, Calif. |
Excerpt from hnpr.org
The Hubble Space Telescope this week celebrates 25 years in Earth's orbit. In that time the telescope has studied distant galaxies, star nurseries, planets in our solar system and planets orbiting other stars.
But, even with all that, you could argue that the astronomer for whom the telescope is named made even more important discoveries — with far less sophisticated equipment.
A young Edwin Hubble at Mount Wilson's 100-inch telescope circa 1922, ready to make history.
Edwin Hubble Papers/Courtesy of Huntington Library, San Marino, Calif.
In the 1920s, Edwin Hubble was working with the 100-inch Hooker telescope on Mount Wilson, just outside Los Angeles. At the time, it was the largest telescope in the world.
On a chilly evening, I climb up to the dome of that telescope with operator Nik Arkimovich and ask him to show me where Hubble would sit when he was using the telescope. Arkimovich points to a platform near the top of the telescope frame.
"He's got an eyepiece with crosshairs on it," Arkimovich explains. The telescope has gears and motors that let it track a star as it moves across the sky. "He's got a paddle that allows him to make minor adjustments. And his job is to keep the star in the crosshairs for maybe eight hours."
"It's certainly much, much easier today," says John Mulchaey, acting director of the observatories at Carnegie Institution of Science. "Now we sit in control rooms. The telescopes operate brilliantly on their own, so we don't have to worry about tracking and things like this."
The headquarters of the Carnegie observatories is at the foot of Mount Wilson, in the city of Pasadena. It's where Hubble worked during the day.
A century's worth of plates are stored here in the basement. Mulchaey opens a large steel door and ushers me into a room filled with dozens of file cabinets.
"Why don't we go take a look at Hubble's famous Andromeda plates," Mulchaey suggests.
The plates are famous for a reason: They completely changed our view of the universe. Mulchaey points to a plate mounted on a light stand.
"This is a rare treat for you," he says. "This plate doesn't see the light of day very often."
This glass side of a photographic plate shows where Hubble marked novas. The red VAR! in the upper right corner marks his discovery of the first Cepheid variable star — a star that told him the Andromeda galaxy isn't part of our Milky Way.
Courtesy of the Carnegie Observatories
The plate shows the spiral shape of the Andromeda galaxy. Hubble was looking for exploding stars called novas in Andromeda. Hubble marked these on the plate with the letter "N."
"The really interesting thing here," Mulchaey says, "is there's one with the N crossed out in red — and he's changed the N to VAR with an exclamation point."
Hubble had realized that what he was seeing wasn't a nova. VAR stands for a type of star known as a Cepheid variable. It's a kind of star that allows you to make an accurate determination of how far away something is. This Cepheid variable showed that the Andromeda galaxy isn't a part of our galaxy.
At the time, most people thought the Milky Way was it — the only galaxy in existence.
"And what this really shows is that the universe is much, much bigger than anybody realizes," Mulchaey says.
It was another blow to our human conceit that we are the center of the universe.
Hubble went on to use the Mount Wilson telescope to show the universe was expanding, a discovery so astonishing that Hubble had a hard time believing it himself.
If Hubble could make such important discoveries with century-old equipment, it makes you wonder what he might have turned up if he'd had a chance to use the space telescope that bears his name.
Excerpt from nytimes.com
The idea began percolating, said Dan Price, the founder of Gravity Payments, after he read an article on happiness. It showed that, for people who earn less than about $70,000, extra money makes a big difference in their lives.
His idea bubbled into reality on Monday afternoon, when Mr. Price surprised his 120-person staff by announcing that he planned over the next three years to raise the salary of even the lowest-paid clerk, customer service representative and salesman to a minimum of $70,000.
“Is anyone else freaking out right now?” Mr. Price asked after the clapping and whooping died down into a few moments of stunned silence. “I’m kind of freaking out.”
If it’s a publicity stunt, it’s a costly one. Mr. Price, who started the Seattle-based credit-card payment processing firm in 2004 at the age of 19, said he would pay for the wage increases by cutting his own salary from nearly $1 million to $70,000 and using 75 to 80 percent of the company’s anticipated $2.2 million in profit this year.
The paychecks of about 70 employees will grow, with 30 ultimately doubling their salaries, according to Ryan Pirkle, a company spokesman. The average salary at Gravity is $48,000 year.
Mr. Price’s small, privately owned company is by no means a bellwether, but his unusual proposal does speak to an economic issue that has captured national attention: The disparity between the soaring pay of chief executives and that of their employees.
The United States has one of the world’s largest pay gaps, with chief executives earning nearly 300 times what the average worker makes, according to some economists’ estimates. That is much higher than the 20-to-1 ratio recommended by Gilded Age magnates like J. Pierpont Morgan and the 20th century management visionary Peter Drucker.
“The market rate for me as a C.E.O. compared to a regular person is ridiculous, it’s absurd,” said Mr. Price, who said his main extravagances were snowboarding and picking up the bar bill. He drives a 12-year-old Audi, which he received in a barter for service from the local dealer.
“As much as I’m a capitalist, there is nothing in the market that is making me do it,” he said, referring to paying wages that make it possible for his employees to go after the American dream, buy a house and pay for their children’s education.
Under a financial overhaul passed by Congress in 2010, the Securities and Exchange Commission was supposed to require all publicly held companies to disclose the ratio of C.E.O. pay to the median pay of all other employees, but it has so far failed to put it in effect. Corporate executives have vigorously opposed the idea, complaining it would be cumbersome and costly to implement.
Mr. Price started the company, which processed $6.5 billion in transactions for more than 12,000 businesses last year, in his dorm room at Seattle Pacific University with seed money from his older brother. The idea struck him a few years earlier when he was playing in a rock band at a local coffee shop. The owner started having trouble with the company that was processing credit card payments and felt ground down by the large fees charged.
When Mr. Price looked into it for her, he realized he could do it more cheaply and efficiently with better customer service.
The entrepreneurial spirit was omnipresent where he grew up in rural southwestern Idaho, where his family lived 30 miles from the closest grocery store and he was home-schooled until the age of 12. When one of Mr. Price’s four brothers started a make-your-own baseball card business, 9-year-old Dan went on a local radio station to make a pitch: “Hi. I’m Dan Price. I’d like to tell you about my brother’s business, Personality Plus.”
His father, Ron Price, is a consultant and motivational speaker who has written his own book on business leadership.
Dan Price came close to closing up shop himself in 2008 when the recession sent two of his biggest clients into bankruptcy, eliminating 20 percent of his revenue in the space of two weeks. He said the firm managed to struggle through without layoffs or raising prices. His staff, most of them young, stuck with him.
Mr. Price said he wasn’t seeking to score political points with his plan. From his friends, he heard stories of how tough it was to make ends meet even on salaries that were still well-above the federal minimum of $7.25 an hour.
“They were walking me through the math of making 40 grand a year,” he said, then describing a surprise rent increase or nagging credit card debt.
“I hear that every single week,” he added. “That just eats at me inside.”
Mr. Price said he wanted to do something to address the issue of inequality, although his proposal “made me really nervous” because he wanted to do it without raising prices for his customers or cutting back on service.
Of all the social issues that he felt he was in a position to do something about as a business leader, “that one seemed like a more worthy issue to go after.”
He said he planned to keep his own salary low until the company earned back the profit it had before the new wage scale went into effect.
Hayley Vogt, a 24-year-old communications coordinator at Gravity who earns $45,000, said, “I’m completely blown away right now.” She said she has worried about covering rent increases and a recent emergency room bill.
“Everyone is talking about this $15 minimum wage in Seattle and it’s nice to work someplace where someone is actually doing something about it and not just talking about it,” she said.
The happiness research behind Mr. Price’s announcement on Monday came from Angus Deaton and Daniel Kahneman, a Nobel Prize-winning psychologist. They found that what they called emotional well-being — defined as “the emotional quality of an individual’s everyday experience, the frequency and intensity of experiences of joy, stress, sadness, anger, and affection that make one’s life pleasant or unpleasant” — rises with income, but only to a point. And that point turns out to be about $75,000 a year.
Of course, money above that level brings pleasures — there’s no denying the delights of a Caribbean cruise or a pair of diamond earrings — but no further gains on the emotional well-being scale.
As Mr. Kahneman has explained it, income above the threshold doesn’t buy happiness, but a lack of money can deprive you of it.
Phillip Akhavan, 29, earns $43,000 working on the company’s merchant relations team. “My jaw just dropped,” he said. “This is going to make a difference to everyone around me.”
At that moment, no Princeton researchers were needed to figure out he was feeling very happy.
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| Researchers have identified thousands of glacier-like formations on the planet. NASA/Levy et al./Nanna Karlsson |
Excerpt from news.discovery.com
Glaciers beneath the dusty sands of Mars contain enough water to coat the planet with more than three feet of ice, a new study shows.
“We have calculated that the ice in the glaciers is equivalent to over 150 billion cubic meters of ice — that much ice could cover the entire surface of Mars with 1.1 meters (3.6 feet) of ice,” Nanna Bjørnholt Karlsson, a post-doctoral researcher the Niels Bohr Institute at the University of Copenhagen, said in a statement.
Radar images previously revealed thousands of buried glacier-like formations in the planet’s northern and southern hemispheres.
That data has now been incorporated into computer models of ice flow to determine the glaciers’ size and hence how much water they contain.
“We have looked at radar measurements spanning 10 years back in time to see how thick the ice is and how it behaves. A glacier is, after all, a big chunk of ice and it flows and gets a form that tells us something about how soft it is. We then compared this with how glaciers on Earth behave and from that we have been able to make models for the ice flow,” she said.
The glaciers are located in belts around Mars between 30 degrees and 50 degrees latitude, roughly equivalent to just south of Denmark’s location on Earth. The glaciers are found on both the northern and southern hemispheres.
The finding could be an important clue to what happened to Mars’ water. The planet, which is now a cold, dry desert, once had oceans, lakes and habitats suitable for microbial life, results from past and ongoing science missions show.
“The ice at the mid-latitudes is an important part of Mars’ water reservoir,” Karlsson said.
Scientists suspect the thick layer of dust covering the ice has saved if from evaporating out into space.
The study appears in this week’s Geophysical Research Letters.
Excerpt from money.cnn.comEurope is in the midst of a massive tussle with American tech giants.The European Union is getting increasingly worried about the dominance of Big Tech and has launched a program to boost the European tech sector. Ap...
This artist's illustration shows interstellar gas, the raw material of star formation, being blown away.Excerpt from cnet.com It takes a mighty wind to keep stars from forming. Researchers have found one in a galaxy far, far away -- and NASA mad...
Excerpt from cbc.ca
Social media reports of a possible UFO sighting last night near Jackhead, Man., are not true, says the Canadian Forces, which attributed the bright light people saw to an airplane from a training exercise.
On Wednesday night (Feb 18th, 2015), several people said on Twitter and Facebook that they saw a bright light in the sky, fuelling speculation that it may have been an unidentified flying object.
The rumour became stronger when photos were posted of Canadian Forces vehicles in the area, with some people claiming the military was there to contain a UFO crash site.
But it was not a UFO at all, says Lt.-Col. Paul Davies, commanding officer 38 Territorial Battalion Group, which is involved in an Arctic Response Company Group training exercise on Lake Winnipeg this week.
Members of the Arctic Response Company Group drive across frozen Lake Winnipeg during Exercise Arctic Bison 2015. (MCpl Cameron Skrypnyk/DND)
"There's no aliens, just my friends in the air force who are out there helping us on this exercise," Davies told CBC News on Thursday.
"I have the commander of that air force contingent sitting right beside me and, you know, he assures us that that was not a UFO, but that was him."
About 150 military personnel are taking part in Exercise Arctic Bison 2015, which includes the 38 Canadian Brigade Group, the 2nd Battalion of the Princess Patricia’s Canadian Light Infantry, the 4th Canadian Ranger Patrol Group, and 440 Squadron of the Royal Canadian Air Force.
Davies said soldiers are training to deal with a plane crash and provide ground search and rescue support in the Arctic.
The bright light that people saw, he explained, came from an airplane that takes off very quickly.
"From a distance it may have looked like it was going straight up in the air, but it wasn't," he said. "It was just us out there playing our games."
The exercise wraps up on Sunday.
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| March 9 Rosetta was 45 miles from Comet 67P/C-G when it photographed the comet’s head ringed with a halo of gas and dust. These jets extend from active areas of the comet’s surface and will become much more prominent over the next few months as the comet approaches the sun. |
Excerpt from dailytimesgazette.com
Astronomers have been on a mission to tail a slow moving comet in the outer space. Their mission started early last 2014, and they are getting better observations than they thought they would.
The comet, Comet 67P, would take 12.4 hours to complete one rotation in the circular path it’s moving in. Controllers of Rosetta are noticing that the icy ball approximately a second every day before it completes a rotation. The flight director of Rosetta – Andrea Accomazzo, said that, “The gas jets coming out of the comet, are acting like thrusters and are slowing down the comet.”
During the Royal Aeronautical Society in London earlier this week, the European Space Agency officially revealed some juicy details on how their team learned to maneuver Rosetta to fly precisely around the massive astral body. Comet 67P is said to weigh 10-billion tons with 4-km size in width.
The controllers and navigators use the landmark-method on the comet to understand its rotation. The team is moving around the outer space relying only on the information provided by the model. Both the model and information guides them in accurately projecting the trajectory of the satellite in the best position.
As they were trying out the model, the ESA team noticed that the landmarks were not following the usual track at the expected time.
During September 2014, the team were determined and very convinced that comet’s rotation period lengthen by 33 milliseconds per day. At present, the comet is approaching the Sun. As it does, it releases great volumes of gas and dust as a result of the so-called Spin-Down effect; further lengthening the rotation period to a second per day.
Accomazzo clarified that Comet 67P is not going to slow down in a slow motion. But its current speed allows them achieve the great magnitude of accuracy in navigating the spacecraft around the comet.
Rosetta made significant observations of the comet last December and January as it moves like an orbit within 30 km distance from the comet. However, this movement is no longer going to happen because Rosetta has retreated from the comet as the gas and dust are being released.
But it does them well as Accomazzo said that, “The aerodynamic effects are now more and more important. The jets are getting stronger and stronger… To give you an idea, these gases come out of the comet for a few kilometers and are moving at 800 meters per second. We definitely have to take this into account. We are a big spacecraft with 64 square meter s of solar panels. We’re like a big sail.”
The trackers were confused during the recent weeks because they have mistaken the dust particles for stars. It was due to the fact that the dusts in the atmosphere were moving around the comet.
Now, Rosetta is using its propulsion system to move in a hyperbolic orbital rotation around Comet 67P. It approaches the comet no closer than 60 to 70 km. With the slowdown of the comet, the ESA team is planning to fly closer.
They were estimating a flight as close as 20 km to get a better look at the surface of the comet and find their lost landing probe, Philae. They lost contact with the robotic probe since November 12 due to lost battery power only days after it successfully landed on the comet.
The slowdown gives them an opportunity to search for Philae. As it moves closer to the Sun, lighting conditions are definitely better than their previous runs. The controllers are now calling onto Philae using radio shout outs.
Philae is solar powered so the team hopes that enough solar energy falls on the panels awaking the probe. But one problem still persist, “The problem is that even if Philae hears Rosetta, it has to have enough charge to turn on its radio transmitter.”
The flight director is quite doubtful if Philae will be awakening. Andrea suggested, “I put it at 50-50, but I will be the happiest person in the world if it happens,”
Their mission achieved great progress and observation of a comet. The team is wishing for better things as the 67P slow down leaving them with more advantage
Excerpt from themarketbusiness.com
A group of biologists was alarmed with the use a new genome-editing technique to modify human DNA in a way that it can become hereditary.
The biologists worry that the new technique is so effective and easy to use that some physicians may push ahead with it before its safety can be weigh up. They also want the public to understand the ethical issues surrounding the technique, which could be used to cure genetic diseases, but also to enhance qualities like beauty or intelligence. The latter is a path that many ethicists believe should never be taken.
“You could exert control over human heredity with this technique, and that is why we are raising the issue,” said David Baltimore, a former president of the California Institute of Technology and a member of the group whose paper on the topic was published in the journal Science.
Ethicists have been concerned for decades about the dangers of altering the human germ line — meaning to make changes to human sperm, eggs or embryos that will last through the life of the individual and be passed on to future generations. Until now, these worries have been theoretical. But a technique invented in 2012 makes it possible to edit the genome precisely and with much greater ease. The technique has already been used to edit the genomes of mice, rats and monkeys, and few doubt that it would work the same way in people.
The new genome-editing technique holds the power to repair or enhance any human gene. “It raises the most fundamental of issues about how we are going to view our humanity in the future and whether we are going to take the dramatic step of modifying our own germline and in a sense take control of our genetic destiny, which raises enormous peril for humanity,” said George Daley, a stem cell expert at Boston Children’s Hospital and a member of the group.
The biologists writing in Science support continuing laboratory research with the technique, and few if any scientists believe it is ready for clinical use. Any such use is tightly regulated in the United States and Europe. American scientists, for instance, would have to present a plan to treat genetic diseases in the human germline to the Food and Drug Administration.
The paper’s authors, however, are concerned about countries that have less regulation in science. They urge that “scientists should avoid even attempting, in lax jurisdictions, germ line genome modification for clinical application in humans” until the full implications “are discussed among scientific and governmental organizations.”
Though such a moratorium would not be legally enforceable and might seem unlikely to exert global sway, there is a precedent. In 1975, scientists worldwide were asked to refrain from using a method for manipulating genes, the recombinant DNA technique, until rules had been established.
“We asked at that time that nobody do certain experiments, and in fact nobody did, to my knowledge,” said Baltimore, who was a member of the 1975 group. “So there is a moral authority you can assert from the U.S., and that is what we hope to do.”
Recombinant DNA was the first in a series of ever-improving steps for manipulating genetic material. The chief problem has always been one of accuracy, of editing the DNA at precisely the intended site, since any off-target change could be lethal. Two recent methods, known as zinc fingers and TAL effectors, came close to the goal of accurate genome editing, but both are hard to use. The new genome-editing approach was invented by Jennifer Doudna of the University of California, Berkeley, and Emmanuelle Charpentier of Umea University in Sweden.
Their method, known by the acronym Crispr-Cas9, co-opts the natural immune system with which bacteria remember the DNA of the viruses that attack them so they are ready the next time those same invaders appear. Researchers can simply prime the defense system with a guide sequence of their choice and it will then destroy the matching DNA sequence in any genome presented to it. Doudna is the lead author of the Science article calling for control of the technique and organized the meeting at which the statement was developed.
Though highly efficient, the technique occasionally cuts the genome at unintended sites. The issue of how much mistargeting could be tolerated in a clinical setting is one that Doudna’s group wants to see thoroughly explored before any human genome is edited.
Scientists also say that replacing a defective gene with a normal one may seem entirely harmless but perhaps would not be.
“We worry about people making changes without the knowledge of what those changes mean in terms of the overall genome,” Baltimore said. “I personally think we are just not smart enough — and won’t be for a very long time — to feel comfortable about the consequences of changing heredity, even in a single individual.”
Many ethicists have accepted the idea of gene therapy, changes that die with the patient, but draw a clear line at altering the germline, since these will extend to future generations. The British Parliament in February approved the transfer of mitochondria, small DNA-containing organelles, to human eggs whose own mitochondria are defective. But that technique is less far-reaching because no genes are edited.
There are two broad schools of thought on modifying the human germline, said R. Alta Charo, a bioethicist at the University of Wisconsin and a member of the Doudna group. One is pragmatic and seeks to balance benefit and risk. The other “sets up inherent limits on how much humankind should alter nature,” she said.
Some Christian doctrines oppose the idea of playing God, whereas in Judaism and Islam there is the notion “that humankind is supposed to improve the world.” She described herself as more of a pragmatist, saying, “I would try to regulate such things rather than shut a new technology down at its beginning.”
Other scientists agree with the Doudna group’s message.
“It is very clear that people will try to do gene editing in humans,” said Rudolf Jaenisch, a stem cell biologist at the Whitehead Institute in Cambridge, Massachusetts, who was not a member of the Doudna group. “This paper calls for a moratorium on any clinical application, which I believe is the right thing to do.”
Writing in Nature last week, Edward Lanphier and other scientists involved in developing the rival zinc finger technique for genome editing also called for a moratorium on human germline modification, saying that use of current technologies would be “dangerous and ethically unacceptable.”
The International Society for Stem Cell Research said Thursday that it supported the proposed moratorium.
The Doudna group calls for public discussion but is also working to develop some more formal process, such as an international meeting convened by the National Academy of Sciences, to establish guidelines for human use of the genome-editing technique.
“We need some principled agreement that we want to enhance humans in this way or we don’t,” Jaenisch said. “You have to have this discussion because people are gearing up to do this.”
Excerpt from smithsonianmag.com
In the hunt for alien life, our first glimpse of extraterrestrials may be in the rainbow of colors seen coming from the surface of an exoplanet.
That's the deceptively simple idea behind a study led by Siddharth Hegde at the Max Planck Institute for Astronomy in Germany. Seen from light-years away, plants on Earth give our planet a distinctive hue in the near-infrared, a phenomenon called red edge. That's because the chlorophyll in plants absorbs most visible light waves but starts to become transparent to wavelengths on the redder end of the spectrum. An extraterrestrial looking at Earth through a telescope could match this reflected color with the presence of oxygen in our atmosphere and conclude there is life here.
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| Eight of the 137 microorganism samples used to measure biosignatures for the catalog of reflection signatures of Earth life forms. In each panel, the top is a regular photograph of the sample and the bottom is a micrograph, a version of the top image zoomed-in 400 times. |
Plants, though, have only been around for 500 million years—a relative blip in our planet's 4.6-billion-year history. Microbes dominated the scene for some 2.5 billion years in the past, and some studies suggest they will rule the Earth again for much of its future. So Hegde and his team gathered 137 species of microorganisms that all have different pigments and that reflect light in specific ways. By building up a library of the microbes' reflectance spectra—the types of colors those microscopic critters reflect from a distance—scientists examining the light from habitable exoplanets can have a plethora of possible signals to search for, the team argues this week in the Proceedings of the National Academy of Sciences.
"No one had looked at the wide range of diverse life on Earth and asked how we could potentially spot such life on other planets, and include life from extreme environments on Earth that could be the 'norm' on other planets," Lisa Kaltenegger, a co-author on the study, says via email. "You can use it to model an Earth that is different and has different widespread biota and look how it would appear to our telescopes."
To make sure they got enough diversity, the researchers looked at temperate-dwelling microbes as well as creatures that live in extreme environments like deserts, mineral springs, hydrothermal vents or volcanically active areas.
While it might seem that alien life could take a huge variety of forms—for instance, something like the silicon-based Horta from Star Trek—it's possible to narrow things down if we restrict the search to life as we know it. First, any life-form that is carbon-based and uses water as a solvent isn't going to like the short wavelengths of light far in the ultraviolet, because this high-energy UV can damage organic molecules. At the other end of the spectrum, any molecule that alien plants (or their analogues) use to photosynthesize won't be picking up light that's too far into the infrared, because there's not enough energy at those longer wavelengths.
In addition, far-infrared light is hard to see through an Earth-like atmosphere because the gases block a lot of these waves, and whatever heat the planet emits will drown out any signal from surface life. That means the researchers restricted their library to the reflected colors we can see when looking at wavelengths in the visible part of the spectrum, the longest wavelength UV and short-wave infrared.
The library won't be much use if we can't see the planets' surfaces in the first place, and that's where the next generation of telescopes comes in, Kaltenegger says. The James Webb Space Telescope, scheduled for launch in 2018, should be able to see the spectra of relatively small exoplanet atmospheres and help scientists work out their chemical compositions, but it won't be able to see any reflected spectra from material at the surface. Luckily, there are other planned telescopes that should be able to do the job. The European Extremely Large Telescope, a 40-meter instrument in Chile, will be complete by 2022. And NASA's Wide Field Infrared Survey Telescope, which is funded and in its design stages, should be up and running by the mid-2020s.
Another issue is whether natural geologic or chemical processes could look like life and create a false signal. So far the pigments from life-forms look a lot different from those reflected by minerals, but the team hasn't examined all the possibilities either, says Kaltenegger. They hope to do more testing in the future as they build up the digital library, which is now online and free for anyone to explore at biosignatures.astro.cornell.edu.
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