Earth

Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets. It is sometimes referred to as the world or the Blue Planet.

Earth formed approximately 4.54 billion years ago, and life appeared on its surface within its first billion years.^[23] Earth'sbiosphere then significantly altered the atmospheric and other basic physical conditions, which enabled the proliferation oforganisms as well as the formation of the ozone layer, which together with Earth's magnetic field blocked harmful solar radiation, and permitted formerly ocean-confined life to move safely to land.^[24] The physical properties of the Earth, as well as itsgeological history and orbit, have allowed life to persist. Estimates on how much longer the planet will be able to continue to support life range from 500 million years (myr), to as long as 2.3 billion years (byr).

Earth's lithosphere is divided into several rigid segments, or tectonic plates, that migrate across the surface over periods of many millions of years. About 71% of the surface is covered by salt water oceans, with the remainder consisting of continents and islands which together have many lakes and other sources of water that contribute to the hydrosphere. Earth's poles are mostly covered with ice that is the solid ice of the Antarctic ice sheet and the sea ice that is the polar ice packs. The planet's interiorremains active, with a solid iron inner core, a liquid outer core that generates the magnetic field, and a thick layer of relatively solid mantle.

Earth gravitationally interacts with other objects in space, especially the Sun and the Moon. During one orbit around the Sun, the Earth rotates about its own axis 366.26 times, creating 365.26 solar days, or one sidereal year.^{[note 7]} The Earth's axis of rotation is tilted 23.4° away from the perpendicular of its orbital plane, producing seasonal variations on the planet's surface with a period of one tropical year (365.24 solar days).^[28] The Moon is Earth's only natural satellite. It began orbiting the Earth about4.53 billion years ago (bya). The Moon's gravitational interaction with Earth stimulates ocean tides, stabilizes the axial tilt, and gradually slows the planet's rotation.

The planet is home to millions of species of life, including humans. Both the mineral resources of the planet and the products of the biosphere contribute resources that are used to support a global human population.^[30] These inhabitants are grouped into about 200 independent sovereign states, which interact through diplomacy, travel, trade, and military action. Human cultureshave developed many views of the planet, including its personification as a planetary deity, its shape as flat, its position as the center of the universe, and in the modern Gaia Principle, as a single, self-regulating organism in its own right.

The spindle spinner

Dashain is a year-round presence in Meera Sthapit’s mind. By February, the lattai-maker and artisan from Banasthali, must have already procured the wood and bamboo that go into making lattais. By the end of August, the lattais must be shipped to the kite-and-lattai stores around Kathmandu. September and October are for last-minute orders, if any. The few days around Dashain are Meera’s downtime, and then it’s back to planning for next year’s festive season and thinking about what upgrades she can make to the few tools she has in the workshop adjacent to her house.

The workshop is a small cinderblock shack with a corrugated-tin roof propped up by bamboo pillars. Inside this barebones structure, among the slats of uttis and lakuri wood and piles of bamboo stems, Meera spends the better part of the year breathing in air thick with sawdust, her body stooped over her homemade lathes.

Meera’s lathes are nowhere close to being the multitasking, precision-timed, finely calibrated workhorses that industrial lathes are, but her machines do get the work done. They are basically motor-and-belt-driven spindle units bolted to the floor, and they can be used—with the right tool-bits and a little bit of ingenuity—to cut circles, sandpaper surfaces, etch grooves and apply spirit and varnish to wood.

Way back, when Meera first started out, she didn’t have such machines to speed up the lattai-making process. Almost 40 years ago, when she was 15 years old, she took up lattai-making because her father needed another pair of hands to help him keep up with the orders. Her grandfather—a carpenter who specialised in making wooden window frames, staircases and banisters—had gotten into lattai-making more for the love of it than to make money. Her grandfather had slapdashed together his first lattai from spare wood and bamboo splints only because he wanted his own homemade lattai to fly his kites. His friends had pleaded with him to make them some too, and before he knew it, he was making lattais for all his friends. By the time Meera’s father got into the craft, lattai-making had become a family business.

For Meera, getting involved in lattai-making was initially more about having a better Dashain for herself. She wasn’t paid an actual hourly wage by her father when she started out, but the money that she was given for her effort (20 or 30 rupees, “a fair-enough tip,” Meera says, because the lattais back then sold for between two to 10 rupees) was enough for her to buy the clothes and knickknacks she had coveted over the year. As she grew older and as her sisters got married and left the family and her brothers started their own businesses and some of them passed away, she took it upon herself to buy better tools, build relations with wood mills to obtain the raw materials, hire a few workers to help increase productivity and, in general, expand the business.

Over the years, she also tinkered with the basic design and materials used for the lattai until she got the model that she wanted. The design calls for using two discs (cut out from planks of lakuri wood) connected by a truss made from bamboo splints; the cylinder thus made is further reinforced around its middle with a disc made from the cheaper uttis wood. Through the centre of this cylinder is inserted a long wooden handle that extends for a good few inches on the outer sides of both discs. Meera etches various designs on the discs to increase the kite-flyer’s grip on the lattai, but other than these variations, all her lattais—the smaller ones start at size two and the biggest one is a size seven—follow the same blueprint.

Meera’s lattais have been well-received and sought by retailers in the Valley for more than three decades now. In fact, all the way through the 1980s and up until around the turn of the century, business was very good. The Internet still hadn’t made much headway in the country, cyber cafes were much fewer, and Nepali kids back then still preferred kite-flying to video games. Today, Meera says, she’s losing customers year-on-year to these distractions.

She says she will continue making lattais for as long as she can, but she knows that to make good money, she will have to take up something else. Her nephew, who lives with her, does help out, but he is more interested in breeding dogs because that venture looks more promising in today’s Kathmandu. He has built a kennel alongside Meera’s workshop and pretty soon, as his business grows, the workshop might have to give up some of its space to the kennel. But Meera says she will still make batches of lattais, until there is no more demand, because the lattai is more than just a product for her. Every lattai that she makes is a family heirloom.

Nobel Dreams

"The Curie story had also demonstrated that the Nobel Prizes had been born at a very lucky time," Feldman noted, a time when international science and literature was becoming "modern" and too specialized for the public to judge without some arbiter handing out the laurels. DNA, the nuclear bomb, and cloning may be hard to comprehend, but everyone understands that "these sciences embody vast and revolutionary might of an uncertain kind," Feldman wrote.

Still, after more than a century of prominence, the strictures of the Nobel Prize-- each one given to no more than three living individuals for specific achievements--seem increasingly unsuitable to the ways of modern science. "The Nobel Prize Is Really Annoying," wrote Caltech physicist Sean Carroll this week on hisPreposterous Universe blog. At least five other scientists, four of them living, cooked up the idea of the Higgs boson, he says, and deserve some credit.

Modern scientists often work in massive teams, whether on the Human Genome Project or at CERN, the European lab that experimentally verified the Higgs particle's existence last year. Pendlebury suggests that the science prizes ought to consider making awards to institutions rather than to specific individuals, and he cites the 2007 Nobel Peace Prize awarded to the Intergovernmental Panel on Climate Change as a precedent.

In any case, McGrayne isn't so sure that regular people are paying attention to the Nobel Prizes anymore, despite the annual news coverage of their announcement.

"Academics compete for it. Institutions 'buy' scientists they've heard are in the running for prizes. Institutions list the number of Nobel Prizes they have on staff," McGrayne said by email. "But this doesn't sound to me like the kind of mass-magazine hero worship that Curie got." When Marie Curie arrived by ship in New York City in 1921, she was flooded by newspaper reporters, and housewives nationwide donated money to buy radium for her institute.

"She's still the only woman scientist that most people can name," McGrayne says. "Do we even know the names of recent winners?"

Madame Curie, Celebrity

Both nationalism and celebrity played a role in boosting the prestige of the Nobel Prize in physics. The prize didn't get much attention until the Curies, Marie and Pierre, won the award in 1903. Marie Curie coined the word "radioactive" and remains one of the best-known scientists in history. It was the first prize that went to French scientists. (See "Start Researching: Marie Curie.")

"Marie Curie's 1903 Nobel for physics created two stars: Curie herself and the science Nobels," says Sharon McGrayne, author of Nobel Prize Women in Science: Their Lives, Struggles and Momentous Discoveries. Until then, the press had covered the literature and peace awards, but physics, chemistry, and medicine seemed too esoteric for news coverage, McGrayne says. "So was radioactivity. But radium—which ironically she would not get a Nobel for until 1911—was glamorous, expensive, a possible cure against cancer, and almost magical as it changed one element into another and produced what seemed like an inexhaustible supply of energy."

The world press had discovered a "rags-to-riches story" in the Curies, Feldman wrote, where penniless scientists cooked up scientific discoveries on an iron stove in a shabby alleyway while tending to an infant.

"Marie Curie herself symbolized the selfless pursuit of science, its humanitarian benefits, and the triumph of the lone individual against impossible odds," McGrayne says. "What more could anyone want? By the end of 1903, Marie was the world's most famous scientist, and the science Nobels were made."

Voila, the cult of the celebrity scientist was born, as journalists "began to feature the personalities behind the prizes," Feldman wrote. A whiff of scandal in Curie's 1911 prize--over her involvement as a widow in an affair with physicist Paul Langevin--only added to the drama.

The Nobel Prize given in 1922 to Einstein increased his stature as a world figure and cemented the portrayal of Nobel Prize winners as heroes and celebrities worthy of notice, McGrayne adds.

Unmatched Renown

"The Nobel has its rivals, but none combines the wealth and prestige of the prize, the range of its subjects, and its century-long record," the late science historian Burton Feldman wrote in The Nobel Prize: A History of Genius, Controversy, and Prestige. Feldman attributed the Nobel's "unmatched renown" to a combination of luck and design.

By design, the Nobel Prize drops a lot of Swedish kronor on its science awardees; some $1.25 million worth will be split among them this year. And it is awarded by royalty, handed over by King Carl XVI Gustaf of Sweden in a December 10 ceremony. Such a combination of money and prestige is tough to top in the modern world.

Feldman argued the Nobel was also lucky to be among the first awards that were international in scope, introduced just as the national rivalries and jealousies that would clash in World War I were reaching a fever pitch. "Science may speak a transnational language, but each year, as the new Nobels are announced, national scorecards and rivalries are anxiously scrutinized," Feldman wrote.

Why else do news stories about the Nobels begin with the national affiliation of the winners, which are carefully noted in the award announcements?

In the early years of the prize, the awards all went to Europeans, and after World War II, U.S. scientists took the lead, Pendlebury says. "Now, when I visit China, they ask, 'When will we have a first Nobel Prize in science?' I tell them it's coming." (A number of Chinese-born scientists have won Nobel Prizes for work done as citizens elsewhere.)

Nobel Prizes Started With a Bang

Blame it on Madame Curie. Mix the French-Polish physicist's early celebrity, some jousting for international prestige before World War I, and the surging importance of physical sciences over the last century, and you have the recipe that made the Nobel Prize—announced every year this week in October—the world's preeminent award.

Big headlines greeted three Americans on Monday after they earned the Nobel Prize in medicine. James Rothman, Randy Schekman, and Thomas Sudhof were honored for unraveling the mystery of how cells shuttle their goods around.

Similar acclaim greeted Belgium's François Englert and Scotland's Peter Higgs, who picked up the award in physics for first contemplating the existence of the subatomic Higgs boson particle, even though it was the least surprising announcement of a physics prize in decades.

The chemistry prize came on Wednesday, awarded to U.S. scientists Michael Levitt and Arieh Warshel, along with Martin Karplus of France's Université de Strasbourg and Harvard. It will be followed by the peace, literature, and economics prizes. Headlines will celebrate each one. (There is even a traditional parody: see "2013 Ig Nobels Honor Research on Beer Goggles, Cows Ready to Be Tipped.")

Why do we care about the Nobel Prize? Since 1901, the awards have been announced annually by the Swedish Academy of Sciences and the Karolinska Institutet in Stockholm, as directed by the will of Swedish "dynamite king" Alfred Nobel, who died in 1897. But why do they get such fanfare?

"There are other prizes, but none are the Nobel Prize," says Thomson Reuters science analyst David Pendlebury, whose team yearly predicts which researchers might be in line for the award. "I'm always surprised by who they pick. But they do an outstanding, thorough job every time." (For the record, Pendlebury and many others this year had their money on Higgs and Englert, after Europe's CERN lab detected a Higgs-like particle in their data last year.)

First Evidence Found of a Comet Strike on Earth

About 28 million years ago a comet exploded over Egypt, creating a 3600°F (2000°C) blast wave that spread out over the desert below. The fiery shockwave melted the sand, forming copious amounts of yellow silica glass scattered over 2,300 square miles (6,000 square kilometers) of the Sahara.

Polished into the shape of a scarab beetle, a large piece of this glass found its way into a brooch owned by the famed Egyptian boy king Tutankhamen.

"Because there is no sign of an impact crater, it has been a mystery as to what kind of celestial event actually could have caused this debris field, but a small, black stone found lying in the middle of the glass area caught our attention," said study co-author David Block, an astronomer at Wits University in Johannesburg, South Africa.

Saharan Surprise

A tiny slice of the black pebble was put through isotopic analysis, which definitely ruled out that it came from a meteor. Instead, the analysis showed that the pebble possessed the unique chemical signature of a comet, measured in terms of elements such as argon and carbon.

"It was then basically a matter of running the movie backwards in time and predicting what temperatures were needed to create the conditions we find that make up the fragment today," Block says. "So when I saw the result of the analyses, I was completely ecstatic to realize that such a piece of cosmic history has been found for the first time right on our doorstep."

While meteors are known to enter the Earth's atmosphere frequently—one can be seen as a shooting star every 15 minutes or so on any random night—not so with comets.

The implosions of comets in planetary atmospheres are exceedingly rare events—the only other definitive case of a comet hitting a planet was back in 1994 when comet Shoemaker-Levy 9 impacted Jupiter's atmosphere.

Astronomical Odds Inspire Caution

And it's because of this rarity that Earth scientist Andrew Glikson of the Australian National University in Canberra, who was not involved in this study, questions if these yellow glass objects, called tektites, might instead have been created through much more common meteoric events, as seen at many impact sites around the world.

"Why can't the material represent a large tektite formed by heating and melting of sand at the Earth's surface by an asteroid impact, such as, for example, the Australite tektites?" asks Glikson.

While this extraterrestrial glass is considered common around many impact sites,  geologist Gerald Johnson, who was not involved in the study, says that beyond the compelling evidence the team presents in their chemical workup of the black pebble, it's not surprising that the research community may be wary of these results.

"A comet, mostly water, vaporizes in the atmosphere and leaves little for the geologic record, while the 'dirt' incorporated in the comet also is disseminated widely and is unlikely to be found because of impact dispersal, surface weathering, and erosion," said Johnson, a meteor impact researcher at the College of William and Mary in Williamsburg, Virginia.

"Undoubtedly, the Earth has been hit numerous times by comets, but our knowledge of these is lacking because comets leave such a poor record ... so this discovery is amazing."

Solar System Origins

Microscopic dust particles from these icy interlopers have been collected from the upper atmosphere and from Antarctic ice, and have been scooped up by space probes.

But having a chance to study sizable comet material firsthand would be exceptional, and Block and his team believe it can offer a unique chance to study the birth of our solar system.

Cosmic particles called presolar grains formed in the stellar cloud of gas and dust that gave birth to our solar system, and are thought to have remained within comets and meteors.

"My bet is that this little rock will unlock some unique secrets in time to come, specifically because it appears packed with presolar grains," said Block.

The comet study will be published in an upcoming issue of Earth and Planetary Science Letters.

10 Cool Things You Didn't Know About Stephen Hawking

Even if you don't keep a close eye on new developments in physics, you've probably heard of the renowned physicist Stephen Hawking. He's prided himself on making his complex physical concepts accessible to the public and writing the bestseller, "A Brief History of Time."

And if you are a fan of Conan O'Brien, "The Simpsons" or "Star Trek," you might have seen him brandishing his cool wit during guest appearances on those shows.

Even if you are familiar with his academic work, however, there are many interesting facts you might not know about Hawking, stretching from his time at school and gradual development of disability to his opinions on the future of the human race.

Many find it surprising, for instance, that, despite his influential body of work, Hawking hasn't yet been awarded the Nobel Prize. We'll talk about some of the remarkable distinctions he has received, however.

Another interesting fact: Hawking was born on Jan. 8, 1942, which just happened to be the 300th anniversary of Galileo's death.

But this has just been the warm-up. Next, we'll delve into some fascinating and unexpected facts about Hawking, including some things about his profoundly inspirational story.

Magic Mushrooms’ Can Improve Spiritual Benefits and Psychological Health

The psychedelic drug in magic mushrooms may have lasting medical and spiritual benefits, according to new research from Johns Hopkins School of Medicine. The mushroom-derived hallucinogen, called psilocybin, is known to trigger transformative spiritual states, but at high doses it can also result in “bad trips” marked by terror and panic. The trick is to get the dose just right, which the Johns Hopkins researchers report having accomplished.

In their study, the Hopkins scientists were able to reliably induce transcendental experiences in volunteers, which offered long-lasting psychological growth and helped people find peace in their lives — without the negative effects.

“The important point here is that we found the sweet spot where we can optimize the positive persistent effects and avoid some of the fear and anxiety that can occur and can be quite disruptive,” says lead author Roland Griffiths, professor of behavioral biology at Hopkins.

Giffiths’ study involved 18 healthy adults, average age 46, who participated in five eight-hour drug sessions with either psilocybin — at varying doses — or placebo. Nearly all the volunteers were college graduates and 78% participated regularly in religious activities; all were interested in spiritual experience.

Fourteen months after participating in the study, 94% of those who received the drug said the experiment was one of the top five most meaningful experiences of their lives; 39% said it was the single most meaningful experience.

Critically, however, the participants themselves were not the only ones who saw the benefit from the insights they gained: their friends, family member and colleagues also reported that the psilocybin experience had made the participants calmer, happier and kinder.

Ultimately, Griffiths and his colleagues want to see if the same kind of psychedelic experience could help ease anxiety and fear over the long term in cancer patients or others facing death. And following up on tantalizing clues from early research on hallucinogenic drugs like LSD, mescaline and psilocybin in the 1960s (which are all now illegal), researchers are also studying whether transcendental experiences could help spur recovery from addiction and treat other psychological problems like depression and post-traumatic stress disorder.

For Griffiths’ current experiment, participants were housed in a living room-like setting designed to be calm, comfortable and attractive. While under the influence, they listened to classical music on headphones, wore eyeshades and were instructed to “direct their attention inward.”

Each participant was accompanied by two other research-team members: a “monitor” and an “assistant monitor,” who both had previous experience with people on psychedelic drugs and were empathetic and supportive. Before the drug sessions, the volunteers became acquainted enough with their team so that they felt familiar and safe. Although the experiments took place in the Hopkins hospital complex in order to ensure prompt medical attention in the event that it was needed, it never was.

As described by early advocates of the use of psychedelics — from ancient shamans to Timothy Leary and the Grateful Dead — the psilocybin experience typically involves a sense of oneness with the universe and with others, a feeling of transcending time, space and other limitations, coupled with a sense of holiness and sacredness. Overwhelmingly, these experiences are difficult to put into words, but many of Griffiths’ participants said they were left with the sense that they understood themselves and others better and therefore had greater compassion and patience.

“I feel that I relate better in my marriage. There is more empathy — a greater understanding of people and understanding their difficulties and less judgment,” said one participant. “Less judging of myself, too.”

Another said: “I have better interaction with close friends and family and with acquaintances and strangers. … My alcohol use has diminished dramatically.”

To zero in on the “sweet spot” of dosing, Griffiths started half the volunteers on a low dose and gradually increased their doses over time (with placebo sessions randomly interspersed); the other half started on a high dose and worked their way down.

Those who started on a low dose found that their experiences tended to get better as the dose increased, probably because they learned what to expect and how to handle it. But people who started with high doses were more likely to experience anxiety and fear (though these feeling didn’t last long and sometimes resolved into euphoria or a sense of transcendence).

“If we back the dose down a little, we have just as much of the same positive effects. The properties of the mystical experience remain the same, but there’s a fivefold drop in anxiety and fearfulness,” Griffiths says.

Some past experiments with psychedelics in the ’60s used initial high doses of the drugs — the “blast people away with a high dose” model, says Griffiths — to try to treat addiction. “Some of the early work in addictions was done with the idea of, ‘O.K., let’s model the ‘bottoming-out’ crisis and make use of the dark side of [psychedelic] compounds. That didn’t work,” Griffiths says.

It may even have backfired: other research on addictions shows that coercion, humiliation and other attempts to produce a sense of “powerlessness,” tend to increase relapse and treatment dropout, not recovery. (And the notorious naked LSD encounter sessions conducted with psychopaths made them worse, too.)

Griffiths is currently seeking patients with terminal cancer to participate in his next set of experiments (for more information on these studies, click here); because psychedelics often produce a feeling of going beyond life and death, they are thought to be especially likely to help those facing the end of life. Griffiths is also studying whether psilocybin can help smokers quit.

Griffiths and other researchers like him are hoping to bring the study of psychedelics into the future. They want to build on the promise that some of the early research showed, while avoiding the bad rep and exaggerated claims — for example, that LSD was harmless and could usher in world peace — that became associated with the drugs when people started using them recreationally in the 1960s. The resulting negative publicity helped shut down the burgeoning research.

This time around, caution may be paying off. Dr. Jerome Jaffe, America’s first drug czar, who was not involved with the research, said in a statement, “The Hopkins psilocybin studies clearly demonstrate that this route to the mystical is not to be walked alone. But they have also demonstrated significant and lasting benefits. That raises two questions: could psilocybin-occasioned experiences prove therapeutically useful, for example in dealing with the psychological distress experienced by some terminal patients?

“And should properly-informed citizens, not in distress, be allowed to receive psilocybin for its possible spiritual benefits, as we now allow them to pursue other possibly risky activities such as cosmetic surgery and mountain-climbing?”