Quantum skyfall puts Einstein's gravity to the test

DIVIDING a falling cloud of frozen atoms sounds like an exotic weather experiment. In fact, it's the latest way to probe whether tiny objects obey Einstein's theory of general relativity, our leading explanation for gravity.

General relativity is based on the equivalence principle, which says that in free fall, all objects fall at the same rate, whatever their mass, provided the only force at work is gravity. That has been proven for large objects: legend has it that Galileo did it first by dropping various balls from the Tower of Pisa. Whether equivalence holds at quantum scales, where gravity's effects are not well understood, isn't clear. Figuring it out could help create a quantum theory of gravity, one of the biggest goals of modern physics.

Creating a quantum equivalent of Galileo's test isn't easy. In 2010 a team led by Ernst Rasel of the University of Hannover in Germany monitored a quantum object in free fall, by tossing a Bose-Einstein condensate (BEC) – a cloud of chilled atoms that behaves as a single quantum object and so is both particle and wave – down a 110-metre tall tower. Now they have split and recombined the wave – all before the BEC, made of rubidium atoms, reached the bottom. This produces an interference pattern that records the path of the falling atoms and can be used to calculate their acceleration (Physical Review Letters, doi.org/km6). The next step is to do the same experiment on a different kind of atom, with a different mass, to see if the equivalence principle holds.

The BEC can only be split for 100 milliseconds in the tower before hitting the bottom, so to allow tiny differences between the atom types to emerge, the work must be repeated in space, where the waves can be split for longer. By showing that a matter-wave can be split and recombined while falling, Rasel's result is a "major step" towards the space version, says Charles Wang of the University of Aberdeen, UK.

This article appeared in print under the headline "Quantum skyfall tests Einstein's gravity"

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Japan says three Chinese ships in disputed waters

TOKYO: Japan's coastguard said three Chinese surveillance ships were in the territorial waters of disputed islands in the East China Sea on Thursday.

The three marine surveillance ships entered the 12-nautical-mile territorial zone off Uotsuri, one of the islands, shortly after 7:00 am (2200 GMT Wednesday), the Japan Coast Guard said in a statement.

Beijing claims the Japanese-controlled islands, called the Senkakus in Japan and Diaoyus in China.

The move was the latest in a series by Chinese government ships since Tokyo nationalised three islands in the chain in September, in what it said was merely an administrative change of ownership. The action sparked fierce protests in China.

- AFP/ck

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11 must-see videos from Mobile World Congress

The 2013 Mobile World Congress is just a day away from closing in Barcelona, Spain. Housed in a brand-new venue and bigger than ever, the show burst at the seams with everything wireless. Sure, there was a ton of new phones and tablets, but those headline devices only scratched the surface. CNET's team of reporters scoured the show floor to find everything from a GPS-enabled cane to a touchless touch screen.

So if you can't be in Barcelona, join CNET for a video tour of some of the hottest devices and most fascinating finds of the show.

 

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The annual event in Barcelona, Spain, produces some of 2013's most exciting smartphone news. CNET covers the show, inside and out.

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Why African Rhinos Are Facing a Crisis

The body count for African rhinos killed for their horns is approaching crisis proportions, according to the latest figures released by the International Union for Conservation of Nature (IUCN).

To National Geographic reporter Peter Gwin, the dire numbers—a rhinoceros slain every 11 minutes since the beginning of 2013—don't come as a surprise. "The killing will continue as long as criminal gangs know they can expect high profits for selling horns to Asian buyers," said Gwin, who wrote about the violent and illegal trade in rhino horn in the March 2012 issue of the magazine.

The recent surge in poaching has been fueled by a thriving market in Vietnam and China for rhino horn, used as a traditional medicine believed to cure everything from hangovers to cancer. Since 2011, at least 1,700 rhinos, or 7 percent of the total population, have been killed and their horns hacked off, according to the IUCN. More than two-thirds of the casualties occurred in South Africa, home to 73 percent of the world's wild rhinos. In Africa there are currently 5,055 black rhinos, listed as critically endangered by the IUCN, and 20,405 white rhinos. (From our blog: "South African Rhino Poaching Hits New High.")

Trying to snuff out poaching by itself won't work, said Gwin. The South African government is fighting a losing battle on the ground to gangs using helicopters, dart guns, high-powered weapons—and lots of money. (National Geographic pictures: The bloody poaching battle over rhino horn [contains graphic images].)

"Every year they get tougher on poaching, but rhino killings continue to rise astronomically," said Gwin. "Somehow they have to address the demand side in a meaningful way. This means either shutting down the Asian markets for rhino horn, or controversially, finding a way to sustainably harvest rhino horns, control their legal sale, and meet what appears to be a huge demand. Either will be a formidable endeavor."

Hope and Hurdles

The signing in December of a memorandum of understanding between South Africa and Vietnam to deal with rhino poaching and other conservation issues raises hope for some concrete action. Observers say the next step is for the two governments to follow through with tangible crime-stopping efforts such as intelligence sharing and other collaboration. The highest hurdle to stopping criminal trade, though, is cultural, Gwin believes. "In Vietnam and China, a lot of people simply believe that as a traditional cure, rhino horn works." (Related: "Blood Ivory.")

The recent climb in rhino deaths threatens what had been a conservation success story. Since 1995, due to better law enforcement, monitoring, and other actions, the overall rhino numbers have steadily risen. The poaching epidemic, the IUCN warns, could dramatically slow and possibly reverse population gains.

The population growth is also being stymied by South Africa's private game farmers, who breed rhinos for sport hunting and tourism and for many years have helped rebuild rhino numbers. Many of them are getting out of the business due to the high costs of security and other risks associated with the poaching invasions.

Those who still have rhinos on their farms will often pay a veterinarian to cut the horns off—under government supervision—to dissuade poachers, but the process costs more than $2,000 and has to be repeated when the horns grow back every two years. Even then the farmers are stuck with horns that are illegal to sell—and which criminals seek to obtain.

Room for Debate

Rhino killings and the trade in their horns will be a major topic at a high-profile conference, the 16th meeting of the Conference of the Parties to the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), which opens in Bangkok March 3. What won't surprise Gwin is if the issue of sustainably harvesting rhino horns from live animals comes up for discussion.

"It's an idea that seems to be gaining traction among some South African politicians and law enforcement circles," he said, noting that the international conservation community strongly opposes any talk of legalizing the trade of rhino horn, sustainably harvested or not. The bottom line for all parties in the discussion is clear, said Gwin: "The slaughter has to stop if rhinos are to survive."

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Arias Prosecutor Too Combative, Experts Say

He has barked, yelled, been sarcastic and demanded answers from accused murderer Jodi Arias this week.

And in doing so, prosecutor Juan Martinez and his aggressive antics may be turning off the jury he is hoping to convince that Arias killed her ex-boyfriend Travis Alexander in June 2008, experts told ABCNews.com today.

"Martinez is his own worst enemy," Mel McDonald, a prominent Phoenix defense attorney and former judge, told ABC News. "He takes it to the point where it's ad nauseam. You have difficulty recognizing when he's driving the point home because he's always angry and pushy and pacing around the courtroom. He loses the effectiveness, rather than build it up."

"He's like a rabid dog and believes you've got to go to everybody's throat," he said.

"If they convict her and give her death, they do it in spite of Juan, not because of him," McDonald added.

Martinez's needling style was on display again today as he pestered Arias to admit that she willingly participated in kinky sex with Alexander, though she previously testified that she only succumbed to his erotic fantasies to please him.

Arias, now 32, and Alexander, who was 27 at the time of his death, dated for a year and continued to sleep together for another year following their break-up.

Arias drove to his house in Mesa, Ariz., in June 2008, had sex with him, they took nude photos together and she killed him in his shower. She claims it was in self-defense. If convicted, Arias could face the death penalty.

Jodi Arias, Prosecutor Butt Heads in Cross-Examination Watch Video

Jodi Arias Maintains She 'Felt Like a Prostitute' Watch Video

Jodi Arias Admits to Killing Man, Lying to Police Watch Video

Martinez also attempted to point out inconsistencies in her story of the killing, bickering with her over details about her journey from Yreka, Calif., to Mesa, Ariz., including why she borrowed gas cans from an ex-boyfriend, when she allegedly took naps and got lost while driving, and why she spontaneously decided to visit Alexander at his home in Mesa for a sexual liaison.

"I want to know what you're talking about," Arias said to Martinez at one point.

"No, I'm asking you," he yelled.

Later, he bellowed, "Am I asking you if you're telling the truth?"

"I don't know," Arias said, firing back at him. "Are you?"

During three days of cross examining Arias this week, Martinez has spent hours going back and forth with the defendant over word choice, her memory, and her answers to his questions.

"Everyone who takes witness stand for defense is an enemy," McDonald said. "He prides himself on being able to work by rarely referring to his notes, but what he's giving up in that is that there's so much time he wastes on stupid comments. A lot of what I've heard is utterly objectionable."

Martinez's behavior has spurred frequent objections of "witness badgering" from Arias' attorney Kirk Nurmi, who at one point Tuesday stood up in court and appealed to the judge to have a conference with all of the attorneys before questioning continued. Judge Sherry Stephens at one point admonished Martinez and Arias for speaking over one another.

Andy Hill, a former spokesperson for the Phoenix police department, and Steven Pitt, a forensic psychiatrist who has testified as an expert witness at many trials in the Phoenix area, both said that despite his aggressive style, Martinez would likely succeed in obtaining a guilty verdict.

"When it comes to cross examination, one size does not fit all," said Pitt. "But if you set aside the incessant sparring, what the prosecutor I believe is effectively doing is pointing out the various inconsistencies in the defendant's version of events."

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Newly spotted comet to buzz Mars in 2014

Lisa Grossman, physical sciences reporter

A Martian sunset, as seen by NASA's Spirit rover in 2005.
(Image: Mars Exploration Rover Mission, Texas A&M, Cornell, JPL, NASA)

There's a new comet in town, and it is making a beeline for Mars. If projections of its orbit are correct, the icy visitor will buzz the Red Planet in October 2014.

Dubbed C/2013 A1, the comet was discovered on 3 January by prolific comet hunter Robert McNaught at Siding Spring Observatory in New South Wales, Australia. Colleagues at the Catalina Sky Survey in Arizona found images of the comet in their catalogue that date back to 8 December 2012, giving additional information about its movements.

These observations allowed astronomers to trace the comet's likely path around the sun. The calculated trajectory has C/2013 A1 crossing Mars' orbit on 19 October 2014, according to Australian blogger Ian Musgrave.

That doesn't necessarily mean a collision will occur. The best estimates right now have the comet passing a safe distance of 900,000 kilometres from the Martian surface. Asteroid 2012 DA14 got much closer to Earth last week, skimming by at a distance of 34,400 kilometres. But with so little data in hand, the calculations are not precise. It's possible the comet will miss Mars by as much as 36 million kilometres - or it could smack right into the planet. "An impact can't be ruled out at this stage," Musgrave wrote.

From Earth, we should be able to see the comet and Mars sitting side by side through small telescopes. And from Mars, the comet could be as spectacular as the expected "supercomet" ISON, which will come into view this year and could outshine the full moon.

Assuming the comet's orbit brings it close enough - but not too close - to Mars, the object should be visible either by rovers on the surface or the armada of Mars-orbiting satellites, which have a history of snapping spectacular shots of the Red Planet and its neighborhood.

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Pope readies for final audience on resignation eve

VATICAN CITY: Pope Benedict XVI will hold the last audience of his pontificate in St Peter's Square on Wednesday on the eve of his historic resignation as leader of the world's 1.2 billion Catholics.

Tens of thousands of pilgrims are expected at the Vatican to bid a final farewell to an 85-year-old pope who abruptly cut short his pontificate by declaring he was too weak in body and mind to keep up with the modern world.

The Vatican says 50,000 people have obtained tickets for the event but many more may come and city authorities are preparing for 200,000, installing metal detectors in the area, deploying snipers and setting up field clinics.

No parking has been allowed in the zone since 10:00 pm Tuesday, and cars were to be barred entirely from 7:00 am on Wednesday.

The weekly audience, which is exceptionally being held in St Peter's Square because of the numbers expected, is to begin at around 10:30 am (0930 GMT) and usually lasts around an hour with a mixture of prayers and religious instruction from the pope.

Benedict will be the first pope to step down since the Middle Ages -- a break with Catholic tradition that has worried conservatives but kindled the hopes of Catholics around the world who want a breath of new life in the Church.

Rome has been gripped by speculation over what prompted Benedict to resign and who the leading candidates might be to replace him.

Rumours and counter-rumours in the Italian media suggest cut-throat behind-the-scenes lobbying, prompting the Vatican to condemn what it has called "unacceptable pressure" to influence the papal election.

Campaign groups have also lobbied the Vatican to exclude two cardinals accused of covering up child sex abuse from the upcoming election conclave.

The Vatican has said Benedict will receive the title of "Roman pontiff emeritus" and can still be addressed as "Your Holiness" and wear the white papal cassock after he officially steps down at 1900 GMT on Thursday.

Just before that time, the Vatican said Benedict will be whisked off by helicopter to the papal summer residence of Castel Gandolfo near Rome where he will begin a life out of the public eye.

Benedict will wave from the residence's balcony one last time before retreating to a private chapel and, as he has said, a life "hidden from the world".

On the hour he formally loses his powers as sovereign pontiff, the liveried Swiss Guard that traditionally protects popes will leave the residence.

The shock of the resignation and its unprecedented nature in the Church's modern history has left the Vatican sometimes struggling to explain the implications and Benedict's future status -- from the banal to the theological.

Some Catholics find it hard to come to terms with the idea that someone who was elected in a supposedly divinely inspired vote could simply resign.

The Vatican has said Benedict will lose his power of divine infallibility -- a sort of supreme authority in doctrinal matters -- as soon as he steps down.

The Vatican has also explained that the personalised gold Fisherman's Ring traditionally used to seal papal documents -- a key symbol of the office -- will be destroyed by a special cardinal, as is customary in Catholic tradition.

Benedict has also chosen to swap his trademark red shoes for a brown pair given to him by artisans in Mexico during a trip last year.

Starting next week, cardinals from around the world will begin a series of meetings to decide what the priorities for the Catholic Church should be, set a start date for the conclave and consider possible candidates for pope.

The conclave -- a centuries-old tradition with an elaborate ritual -- is supposed to be held within 15 to 20 days of the death of the pope, but Benedict has given special dispensation for the cardinals to bring that date forward.

Cardinals have been flying in from around the world including US prelate Roger Mahony, a former archbishop of Los Angeles stripped of all church duties for mishandling and covering up sex abuse claims against dozens of priests.

A total of 115 "cardinal electors" are scheduled to take part after another voter, British cardinal Keith O'Brien said he would not be taking part after allegations emerged that he made unwanted advances towards priests in the 1980s.

- AFP/ck

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Tech companies: gay marriage ban is bad for business

Apple is one of the companies signing up to support gay marriage.

(Credit:
Apple)

Some big-name tech companies are adding their support for same-sex marriage and making the case that banning these unions deters employee recruitment efforts.

Dozens of companies, including Apple, Facebook, eBay, and Intel, will file an amicus brief -- a court document field by an interested group that is not actually a party to the case -- on Thursday to declare their support, Fortune reported today.

The companies will file the brief in connection with the Hollingsworth v. Perry case, which will decide whether the Fourteenth Amendment prohibits California from defining marriage as a union between a man and a woman. The Fourteenth Amendment prohibits states from denying any person equal protection under the law.

The companies argue that a ban would make it harder for businesses in California to hire potential employees if those employees think they would receive better treatment and benefits in another state, or another country, according to the draft brief obtained by Fortune.

The tech companies join dozens of others, as well as top Republicans, including HP's Meg Whitman, who think the state should not ban gay marriage.

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A History of Balloon Crashes

A hot-air balloon exploded in Egypt yesterday as it carried 19 people over ancient ruins near Luxor. The cause is believed to be a torn gas hose. In Egypt as in many other countries, balloon rides are a popular way to sightsee. (Read about unmanned flight in National Geographic magazine.)

The sport of hot-air ballooning dates to 1783, when a French balloon took to the skies with a sheep, a rooster, and a duck. Apparently, they landed safely. But throughout the history of the sport, there have been tragedies like the one in Egypt. (See pictures of personal-flight technology.)

1785: Pioneering balloonist Jean-Francois Pilatre de Rozier and pilot Pierre Romain died when their balloon caught fire, possibly from a stray spark, and crashed during an attempt to cross the English Channel. They were the first to die in a balloon crash.

1923: Five balloonists participating in the Gordon Bennett Cup, a multi-day race that dates to 1906, were killed when lightning struck their balloons.

1924: Meteorologist C. LeRoy Meisinger and U.S. Army balloonist James T. Neely died after a lightning strike. They had set off from Scott Field in Illinois during a storm to study air pressure. Popular Mechanics dubbed them "martyrs of science."

1995: Tragedy strikes the Gordon Bennett Cup again. Belarusian forces shot down one of three balloons that drifted into their airspace from Poland. The two Americans on board died. The other balloonists were detained and fined for entering Belarus without a visa. (Read about modern explorers who take to the skies.)

1989: Two hot air balloons collided during a sightseeing trip near Alice Springs, Australia. One balloon crashed to the ground killing all 13 people on board. The pilot of the other balloon was sentenced to a two-year prison term for "committing a dangerous act." Until today, this was considered the most deadly balloon accident.

2012: A balloon hit a power line and caught fire in New Zealand, killing all 11 on board. Investigators later determined that the pilot was not licensed to fly and had not taken  proper safety measures during the crash, like triggering the balloon's parachute and deflation system.

2012: A sightseeing balloon carrying 32 people crashed and caught fire during a thunderstorm in the Ljubljana Marshes in Slovenia. Six died; many other passengers were injured.

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Arias Liked Some Kinky Sex, She Admits

Though accused murderer Jodi Arias said she sometimes felt "like a prostitute" at the hands of her ex-boyfriend, Travis Alexander, she admitted today that she often enjoyed their sex life and even suggested sex acts they could try.

Prosecutor Juan Martinez, after a day of aggressive questioning and bickering with Arias, asked her about her own suggestions for her sex life with Alexander, including a phone conversation in which she suggested using sexual lubricant.

Arias, 32, is accused of killing Alexander, but claims it was in self-defense.
Timeline of the Jodi Arias Trial

"You introduced KY Jelly into the relationship to make it more sexually enjoyable, right? When we're talking about the level of experimentation, it looks like both of you were experimenting together sexually. So when we hear things like, 'I felt like a prostitute,' that's not exactly true, is it?" Martinez said.

"It was often mutual," Arias said. "I didn't feel like a prostitute during, just after."

Jodi Arias Admits to Killing Man, Lying to Police Watch Video

Jodi Arias Testimony: Prosecution's Cross-Examination Watch Video

Martinez showed the jury a text message Arias sent offering to perform oral sex on Alexander, comparing it to a statement she made on direct testimony saying that she once felt like a prostitute when Alexander tossed a piece of chocolate at her and walked away without a word after she performed oral sex.

"How is it you can say you 'felt like a prostitute' when you're moving the relationship ahead like this?" Martinez asked. "The act itself is the same thing, and here you're requesting it. The geography is different, but that aside, isn't it the same act? And you're requesting it?"

"When he (ejaculated) and left afterward I felt like a prostitute. When we mutually went through things together I didn't," she said.

Arias also admitted that she sent Alexander a topless photo of herself after he sent her photos of his penis, and that she only did it after she had her breasts enhanced surgically.

Catching Up on the Trial? Check Out ABC News' Jodi Arias Trial Coverage

The testimony came as Martinez continued his efforts to discredit Arias' testimony on the stand, including her statements that she often succumbed to Alexander's sexual fantasies so she wouldn't hurt his feelings. Martinez has focused on portraying Arias as a liar for much of his direct examination.

Arias is charged with murder for killing her ex-boyfriend Travis Alexander at his home in Mesa, Ariz., in June 2008. She claims she killed him in self defense and that he had been increasingly violent and sexually demanding in the months before the confrontation. She also claimed he was interested in young boys.

The prosecution claims she killed him in a jealous rage. She could face the death penalty if convicted of first degree murder.

Jodi Arias Trial See Tempers Flare

Earlier in the day,tempers flared between Arias and prosecutor Martinez as the prosecutor tried to detail Arias' history of spying on her boyfriends, but Arias complained that his aggressive style of questioning made her "brain scramble."

Arias and Martinez, who have sparred throughout two prior days of cross-examination, spent more than 10 minutes bickering over Martinez's word choices and his apparent "anger."

The morning's testimony, and Martinez's points about Arias' alleged spying, were largely interrupted by the spats.

"Are you having trouble understanding me?" Martinez yelled.

"Yes because sometimes cause you go in circles," Arias answered.

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