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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Excerpt from csmonitor.com
Thanks to a phenomenon known as gravitational lensing, the Hubble Space Telescope has captured four images of the same supernova explosion.
For the first time, a cosmic magnifying glass has allowed scientists to see the same star explosion four times, possibly offering a revealing glimpse into these explosive stellar deaths and the nature of the accelerating universe.
Astronomers using the Hubble Space Telescope have captured four images of a supernova explosion in deep space thanks to a galaxy located between Earth and the massive star explosion. You can see how Hubble saw the supernova in this NASA video. The galaxy cluster warped the fabric of space and time around it — like a bowling ball placed on a bed sheet — allowing scientists to see the supernova in four images.
"It was predicted 50 years ago that a supernova could be gravitationally lensed like this, but it's taken a long time for someone to find an example," lead study author Patrick Kelly, an astronomer at the University of California, Berkeley told Space.com. "It's fun to have been able to find the first one."
The supernova, which was discovered on Nov. 11, 2014, is located about 9.3 billion light-years away from Earth, near the edge of the observable universe. The researchers have named the distant supernova SN Refsdal in honor of the late Norwegian astrophysicist Sjur Refsdal, a pioneer of gravitational lensing studies. Due to gravitational lensing, "the supernova appears 20 times brighter than its normal brightness," study co-author Jens Hjorth, head of the Dark Cosmology Centre at the Niels Bohr Institute at the University of Copenhagen, said in a statement.
The lensing galaxy, which is about 5 billion light-years from Earth, is part of a large cluster of galaxies known MACS J1149.6+2223. In 2009, astronomers discovered that this cluster was the source of the largest known image of a spiral galaxy ever seen through a gravitational lens.
The four images of the supernova each appeared separately over the course of a few weeks. This is because light can take various paths around and through a gravitational lens, arriving at Earth at different times.
Using gravity as a lens
Gravity is created when matter warps the fabric of reality. The greater the mass of an object, the more space-time curves around that object and the stronger its gravitational pull, the discovery enshrined in Einstein's theory of general relativity, which celebrates its centennial this year.
As a result, gravity can also bend light like a lens, meaning objects see n behind powerful gravitational fields, such as those of massive galaxies, are magnified. Gravitational lensing was first discovered in 1979, and today gravitational lenses can help astronomers see features otherwise too distant and faint to detect with even the largest telescopes.
"These gravitational lenses are like a natural magnifying glass. It's like having a much bigger telescope," Kelly said in a statement. "We can get magnifications of up to 100 times by looking through these galaxy clusters."
When light is far from a gravitationally lensing mass, or if the gravitationally lensing mass is not especially large, only "weak lensing" occurs, barely distorting the light. However, when the light comes from almost exactly behind the gravitationally lensing mass, "strong lensing" can happen.
When a strongly lensed object occupies a large patch of space — for instance, if it's a galaxy — it can get smeared into an "Einstein ring" surrounding a gravitationally lensing mass. However, strong lensing of small, pointlike items — for instance, super-bright objects known as quasars — often produces multiple images surrounding the gravitationally lensing mass, resulting in a so-called "Einstein cross."
The observations of SN Refsdal mark the first time astronomers on Earth have witnessed strong lensing of a supernova, with four images of an exploding star arrayed as an Einstein cross.
An expanding universe
These new findings could help scientists measure the accelerating rate at which the universe is expanding, researchers say.
A computer model of the lensing cluster suggests the scientists missed chances to see the lensed supernova 50 and 10 years ago. However, the model also suggests more images of the explosion will repeat again within the next 10 years.
The timing of when all these images of the supernova arrive depends on the gravitational pull of the matter generating the gravitational lens. So, by measuring those times, the researchers hope to map how visible normal matter and invisible dark matter is distributed in the lensing galaxy.
Dark matter is currently one of the greatest mysteries in science, a poorly understood substance thought to make up five-sixths of all matter in the universe. A better understanding of how dark matter is behaving in this gravitationally lensing cluster might help shed light on the material's nature, Kelly said.
Analyzing when the images arrive could also help scientists pinpoint the rate at which the universe is expanding. Although there are already several ways to measure the cosmic expansion rate, "there has been a lot of heated debate between different methods, so it'd be interesting to see how this new technique might affect the area," Kelly said. "It's always nice to have completely independent measurements of the same quantity."
The scientists detailed their findings in the March 6 issue of the journal Science.
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| Artist impression of Mars ocean |
Excerpt from news.discovery.com
Mars was once a small, wet and blue world, but over the past 4 billion years, Mars dried up and became the red dust bowl we know today.
But how much water did Mars possess? According to research published in the journal Science, the Martian northern hemisphere was likely covered in an ocean, covering a region of the approximate area as Earth’s Atlantic Ocean, plunging, in some places, to 1.6 kilometers (1 mile) deep.
“Our study provides a solid estimate of how much water Mars once had, by determining how much water was lost to space,” said Geronimo Villanueva, of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and lead author of the new paper, in an ESO news release. “With this work, we can better understand the history of water on Mars.”
Over a 6-year period, Villanueva and his team used the ESO’s Very Large Telescope (in Chile) and instruments at the W. M. Keck Observatory and the NASA Infrared Telescope Facility (both on Mauna Kea in Hawaii) to study the distribution of water molecules in the Martian atmosphere. By building a comprehensive map of water distribution and seasonal changes, they were able to arrive at this startling conclusion.
It is becoming clear that, over the aeons, Mars lost the majority of its atmosphere to space. That also goes for its water. Though large quantities of water were likely frozen below the surface as the atmosphere thinned and cooled, the water contained in an ocean of this size must have gone elsewhere — it must have also been lost to space.
The water in Earth’s oceans contains molecules of H2O, the familiar oxygen atom bound with 2 hydrogen atoms, and, in smaller quantities, the not-so-familiar HDO molecule. HDO is a type of water molecule that contains 1 hydrogen atom, 1 oxygen atom and 1 deuterium atom. The deuterium atom is an isotope of hydrogen; whereas hydrogen consists of 1 proton and an electron, deuterium consists of 1 proton, 1 neutron and 1 electron. Therefore, due to the extra neutron the deuterium contains, HDO molecules are slightly heavier than the regular H2O molecules.
Also known as “semi-heavy water,” HDO is less susceptible to being evaporated away and being lost to space, so logic dictates that if water is boiled (or sublimated) away on Mars, the H2O molecules will be preferentially lost to space whereas a higher proportion of HDO will be left behind.
By using powerful ground-based observatories, the researchers were able to determine the distribution of HDO molecules and the H2O molecules and compare their ratios to liquid water that is found in its natural state.
Of particular interest is Mars’ north and south poles where icecaps containing water and carbon dioxide ice persist to modern times. The water those icecaps contain is thought to document the evolution of water since the red planet’s wet Noachian period (approximately 3.7 billion years ago) to today. It turns out that the water measured in these polar regions is enriched with HDO by a factor of 7 when compared with water in Earth’s oceans. This, according to the study, indicates that Mars has lost a volume of water 6.5 times larger than the water currently contained within the modern-day icecaps.
Therefore, the volume of Mars’ early ocean must have been at least 20 million cubic kilometers, writes the news release.
Taking into account the Martian global terrain, most of the water would have been concentrated around the northern plains, a region dominated by low-lying land. An ancient ocean, with this estimate volume of water, would have covered 19 percent of the Martian globe, a significant area considering the Atlantic Ocean covers 17 percent of the Earth’s surface.
“With Mars losing that much water, the planet was very likely wet for a longer period of time than previously thought, suggesting the planet might have been habitable for longer,” said Michael Mumma, also of NASA’s Goddard Space Flight Center.
This estimate is likely on the low-side as Mars is thought to contain significant quantities of water ice below its surface — a fact that surveys such as this can be useful for pinpointing exactly where the remaining water may be hiding.
Ulli Kaeufl, of the European Southern Observatory and co-author of the paper, added: “I am again overwhelmed by how much power there is in remote sensing on other planets using astronomical telescopes: we found an ancient ocean more than 100 million kilometers away!”
Source: ESO
But how much water did Mars possess? According to research published in the journal Science, the Martian northern hemisphere was likely covered in an ocean, covering a region of the approximate area as Earth’s Atlantic Ocean, plunging, in some places, to 1.6 kilometers (1 mile) deep.
“Our study provides a solid estimate of how much water Mars once had, by determining how much water was lost to space,” said Geronimo Villanueva, of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and lead author of the new paper, in an ESO news release. “With this work, we can better understand the history of water on Mars.”
Over a 6-year period, Villanueva and his team used the ESO’s Very Large Telescope (in Chile) and instruments at the W. M. Keck Observatory and the NASA Infrared Telescope Facility (both on Mauna Kea in Hawaii) to study the distribution of water molecules in the Martian atmosphere. By building a comprehensive map of water distribution and seasonal changes, they were able to arrive at this startling conclusion.
It is becoming clear that, over the aeons, Mars lost the majority of its atmosphere to space. That also goes for its water. Though large quantities of water were likely frozen below the surface as the atmosphere thinned and cooled, the water contained in an ocean of this size must have gone elsewhere — it must have also been lost to space.
This artist’s impression shows how Mars may have looked about four billion years ago. The young planet Mars would have had enough water to cover its entire surface in a liquid layer about 140 meters deep, but it is more likely that the liquid would have pooled to form an ocean occupying almost half of Mars’s northern hemisphere.
Also known as “semi-heavy water,” HDO is less susceptible to being evaporated away and being lost to space, so logic dictates that if water is boiled (or sublimated) away on Mars, the H2O molecules will be preferentially lost to space whereas a higher proportion of HDO will be left behind.
By using powerful ground-based observatories, the researchers were able to determine the distribution of HDO molecules and the H2O molecules and compare their ratios to liquid water that is found in its natural state.
Of particular interest is Mars’ north and south poles where icecaps containing water and carbon dioxide ice persist to modern times. The water those icecaps contain is thought to document the evolution of water since the red planet’s wet Noachian period (approximately 3.7 billion years ago) to today. It turns out that the water measured in these polar regions is enriched with HDO by a factor of 7 when compared with water in Earth’s oceans. This, according to the study, indicates that Mars has lost a volume of water 6.5 times larger than the water currently contained within the modern-day icecaps.
Therefore, the volume of Mars’ early ocean must have been at least 20 million cubic kilometers, writes the news release.
Taking into account the Martian global terrain, most of the water would have been concentrated around the northern plains, a region dominated by low-lying land. An ancient ocean, with this estimate volume of water, would have covered 19 percent of the Martian globe, a significant area considering the Atlantic Ocean covers 17 percent of the Earth’s surface.
“With Mars losing that much water, the planet was very likely wet for a longer period of time than previously thought, suggesting the planet might have been habitable for longer,” said Michael Mumma, also of NASA’s Goddard Space Flight Center.
This estimate is likely on the low-side as Mars is thought to contain significant quantities of water ice below its surface — a fact that surveys such as this can be useful for pinpointing exactly where the remaining water may be hiding.
Ulli Kaeufl, of the European Southern Observatory and co-author of the paper, added: “I am again overwhelmed by how much power there is in remote sensing on other planets using astronomical telescopes: we found an ancient ocean more than 100 million kilometers away!”
Source: ESO
Photo : NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/PSI Excerpt from sciencetimes.com Originally discovered in 1801 by an astronomer in Sicily, Ceres has had quite an interesting history to date. Originally believed to be a shining star in the sky, when i...
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To infinity and beyond? Maggie Lieu Photo: Peter Quinnell |
From telegraph.co.uk
By Nick Curtis
On a different planet - Nick Curtis imagines a message from 'Martianaut' Maggie Lieu to her parents back at home
Mars Mission, British Martianaut Maggie Lieu’s Log
Day One: Stardate 22/02/2025.
Hello Mission Control.... Just kidding! Hi mum, hi dad, or should I say earthlings!
Well, me and Bruce the Australian Martianaut finally touched down beside the Herschel II Strait on the red planet today, the last of 12 pairs to arrive - though as you know it was touch and go. Ten years of training and research almost went down the drain when Google got hit by a massive retrospective tax bill and had to withdraw all its branded sponsorship from the starship at the last minute:
fortunately Amazon stepped in, on the agreement we install its first matter transference delivery portal (“It’s there before you know it”) here. And rename the ship Bezos 1, of course
fortunately Amazon stepped in, on the agreement we install its first matter transference delivery portal (“It’s there before you know it”) here. And rename the ship Bezos 1, of course
The trip was textbook, with both of us uploading videos on how to apply makeup and bake cupcakes in space direct to the Weibo-spex of our crowdsource funders in China - great practice for The Great Martian Bakeoff on BBC 12 next year (subscribers only). The one hairy moment was a near miss with that Virgin Galactic rocket, Beardie IV, that went AWOL five years ago. We were so close we could see Leonardo diCaprio’s little screaming face pressed against his porthole. And Kim Kardashian’s bum pressed against hers - though it’s looking kinda old now and I hoped we’d seen the last of it.
So what can I tell you? When we landed the others threw us a party with full fat milk, rare beef and waffles (the only official space superfoods since it was discovered that kale and quinoa cause impotence). The landscape is pretty barren, just acres of rolling sand and no one in sight, sort of like Greece after it left the Eurozone and the entire population moved to Germany. Or like the so-called Caliphate after Islamic State finally perfected its time machine and managed to transport itself and all its followers back to the 12th century.
The temperature outside is about 20c, so a lot cooler than it is at home since the ice caps melted. There’s water here, but not as much as is now covering Indonesia, Holland and Somerset. The atmosphere is 96% carbon dioxide so Juan, the Spanish Martianaut, had to keep his suit on when he went out to smoke. He tried to get us all to buy duty free for him in Mexico City spaceport before we left, now that a pack of cigarettes costs 450 Euros in the shops, and they’ve been camouflaged so you can’t find them.
The construction-droids did a pretty good job building Mars Camp out of the recycled parts of all those closed Tesco Metros. They say we have enough air up here to last 20 years, Earth’s stocks of storable oxygen having increased tenfold when the European Parliament collapsed following the expenses scandal. I still can’t believe that Dasha Putin-Mugabe was claiming for SIX driverless cars while she was EU President, and employing her wife as her accountant. And her being the first transgender Russian lesbian to hold the office, too.
Speaking of politics, how is life in coalition Britain? Who has the upper hand at the moment? UKIP? Scots Nats? The Greens? or those nutters from Cornwall, Mebion Kernow? Or are they underwater now. And how is young Straw doing now Labour is the smallest party in Parliament, after the New New New Conservatives? Hard to believe it’s three years since the last Lib Dem lost her seat.
I gather that some things have improved internationally now that Brian Cox has developed his own time machine at the Wowcher-Hawking Institute in Cambridge, and worked out that the entire world can now transport all its waste products back to the Caliphate in the 12th century.
We can see the Earth from here through the Clinton2020 Telescope that the US president endowed us with after her brief period in office. The joke up here is that she did it to keep a proper eye either on her husband (though he doesn’t get around so much any more, obviously) or on what President Palin is up to. I still can’t believe that she sold Alaska to Russia to pay the compensation bill for the Grand Canyon Fracking Collapse.
Even through the Clinton2020 the Earth looks pretty small, though at times, when the stars are really bright, we can see the Great Wall 2 ring of laser satellites that China has pointed at Russia to discourage any more “accidental” incursions.
Our team up here is like a microcosm of human life on earth. Well, up to a point. As you know the French and Italian Martianauts were expelled from the team before lift-off, because of some scandal or other. We weren’t told if it was financial or sexual but a space bra and a data stick with three million Bitcoins on it were found in the airlock.
The African and Brazilian Martianauts swan around the place as if they PERSONALLY solved the world’s food and energy problems.
And the North Korean guy just sits in the corner, muttering into some device up his sleeve and scowling. All the freeze-dried cheese has gone and he’s looking quite fat, if you get my meaning.
I don’t get much time to myself, what with work, the non-denominational Sorry Meetings where we apologise in case we’ve accidently offended someone’s beliefs, and the communal space-pilates sessions (the North Korean guy skips those so he may be in line for a compulsory gastric band, as mandated by the Intergalactic Health Organisation).
I always try and upload the latest Birmingham City Games onto my cortex chip when I feel homesick: I know it's not fashionable, but I think football got better when they replaced the players with robots and the wage bill - and the number of court cases - dropped to zero. I know the electricity bill is massive, but the new Brazilian solar technology should fix that.
Anyway, got to run now. We’re putting together a bid to have the 2036 Olympics up here.
Bye, or as we say on Mars - see you on the dark side.
The temperature outside is about 20c, so a lot cooler than it is at home since the ice caps melted. There’s water here, but not as much as is now covering Indonesia, Holland and Somerset. The atmosphere is 96% carbon dioxide so Juan, the Spanish Martianaut, had to keep his suit on when he went out to smoke. He tried to get us all to buy duty free for him in Mexico City spaceport before we left, now that a pack of cigarettes costs 450 Euros in the shops, and they’ve been camouflaged so you can’t find them.
Maggie Lieu (Guardian)
The construction-droids did a pretty good job building Mars Camp out of the recycled parts of all those closed Tesco Metros. They say we have enough air up here to last 20 years, Earth’s stocks of storable oxygen having increased tenfold when the European Parliament collapsed following the expenses scandal. I still can’t believe that Dasha Putin-Mugabe was claiming for SIX driverless cars while she was EU President, and employing her wife as her accountant. And her being the first transgender Russian lesbian to hold the office, too.
Speaking of politics, how is life in coalition Britain? Who has the upper hand at the moment? UKIP? Scots Nats? The Greens? or those nutters from Cornwall, Mebion Kernow? Or are they underwater now. And how is young Straw doing now Labour is the smallest party in Parliament, after the New New New Conservatives? Hard to believe it’s three years since the last Lib Dem lost her seat.
I gather that some things have improved internationally now that Brian Cox has developed his own time machine at the Wowcher-Hawking Institute in Cambridge, and worked out that the entire world can now transport all its waste products back to the Caliphate in the 12th century.
We can see the Earth from here through the Clinton2020 Telescope that the US president endowed us with after her brief period in office. The joke up here is that she did it to keep a proper eye either on her husband (though he doesn’t get around so much any more, obviously) or on what President Palin is up to. I still can’t believe that she sold Alaska to Russia to pay the compensation bill for the Grand Canyon Fracking Collapse.
Even through the Clinton2020 the Earth looks pretty small, though at times, when the stars are really bright, we can see the Great Wall 2 ring of laser satellites that China has pointed at Russia to discourage any more “accidental” incursions.
Our team up here is like a microcosm of human life on earth. Well, up to a point. As you know the French and Italian Martianauts were expelled from the team before lift-off, because of some scandal or other. We weren’t told if it was financial or sexual but a space bra and a data stick with three million Bitcoins on it were found in the airlock.
The African and Brazilian Martianauts swan around the place as if they PERSONALLY solved the world’s food and energy problems.
And the North Korean guy just sits in the corner, muttering into some device up his sleeve and scowling. All the freeze-dried cheese has gone and he’s looking quite fat, if you get my meaning.
I don’t get much time to myself, what with work, the non-denominational Sorry Meetings where we apologise in case we’ve accidently offended someone’s beliefs, and the communal space-pilates sessions (the North Korean guy skips those so he may be in line for a compulsory gastric band, as mandated by the Intergalactic Health Organisation).
I always try and upload the latest Birmingham City Games onto my cortex chip when I feel homesick: I know it's not fashionable, but I think football got better when they replaced the players with robots and the wage bill - and the number of court cases - dropped to zero. I know the electricity bill is massive, but the new Brazilian solar technology should fix that.
Anyway, got to run now. We’re putting together a bid to have the 2036 Olympics up here.
Bye, or as we say on Mars - see you on the dark side.
Excerpt from (CNN) -- Three billion miles away from Earth, in an unchartered slice of our solar system, a small space probe is shaking off its deep sleep and getting ready to become the first spacecraft to visit Pluto and its moons.It's the "beginni...
Excerpt from
time.com
A new analysis of Mars One's plans to colonize the Red Planet finds that the explorers would begin dying within 68 days of touching down
Hear that? That’s the sound of 200,000 reservations being reconsidered. Two hundred thousand is the announced number of intrepid folks who signed up last year for the chance to be among the first Earthlings to colonize Mars, with flights beginning as early as 2024. The catch: the trips will be one way, as in no return ticket, as in farewell friends, family, charbroiled steaks and vodka martinis, to say nothing of such everyday luxuries as modern hospitals and, you know, breathable air.
But the settlers in Jamestown weren’t exactly volunteering for a weekend in Aspen either, and in both cases, the compensations—being the first people on a distant shore—seemed attractive enough. Now, however, the Mars plan seems to have run into a teensy snag. According to a new analysis by a team of grad students at MIT, the new arrivals would begin dying within just 68 days of touching down.
So what could go wrong? That’s what the four MIT students set out to find out, and the short answer is: a lot.
The biggest problem, the students discovered, concerns that business of breathable air. One of the things that’s always made Earth such a niftily habitable place to live is that what animals exhale, plants inhale, and vice versa. Since the Martian astronauts and their crops would be living and respiring in the same enclosed habitats, a perfect closed loop should result in which we provide them all the carbon dioxide they need and they return the favor with oxygen.
Only it doesn’t, the MIT students found. The problem begins with the lettuce and the wheat, both of which are considered essential crops. As lettuce matures, peaking about 30 days after planting, it pushes the 02 level past what’s known as .3 molar fractions, which, whatever it means, doesn’t sound terribly dangerous — except it’s also the point at which the threat of fire rises to unacceptable levels. That risk begins to tail off as the crop is harvested and eaten, but it explodes upward again, far past the .3 level, at 68 days when the far gassier wheat matures.
A simple answer would be simply to vent a little of the excess O2 out, which actually could work, except the venting apparatus is not able to distinguish one gas from another. That means that nitrogen—which would, as on Earth, make up the majority of the astronauts’ atmosphere—would be lost too. That, in turn, would lower the internal pressure to unsurvivable levels—and that’s what gets your 68-day doomsday clock ticking.
There is some question too about whether the hardware that Mars One is counting on would even be ready for prime time. The mission planners make much of the fact that a lot of what they’re planning to use on Mars has already been proven aboard the International Space Station (ISS), which is true enough. But that hardware is built to operate in microgravity—effectively zero g—while Mars’s gravity is nearly 40% of Earth’s. So a mechanical component that would weigh 10 lbs. on Earth can be designed with little concern about certain kinds of wear since it would weigh 0 lbs. in orbit. But on Mars it would be 4 lbs., and that can make all the difference.
“The introduction of a partial gravity environment,” the grad students write, “will inevitably lead to different [environmental] technologies.”
For that and other reasons, technical breakdowns are a certainty. The need for replacement parts is factored into Mars One’s plans, but probably not in the way that they should be. According to the MIT team, over the course of 130 months, spare parts alone would gobble up 62% of the payload space on resupply missions, making it harder to get such essentials as seeds, clothes and medicine—to say nothing of other crew members—launched on schedule.
Then too, there is the question of habitat crowding. It’s easy to keep people alive if you feed them, say, a single calorie-dense food product every day. But energy bars forever means quickly losing your marbles, which is why Mars One plans for a variety of crops—just not a big enough variety. “Given that the crop selection will significantly influence the wellbeing of the crew for the entirety of their lives after reaching Mars,” the authors write, “we opt for crop variety over minimizing growth area.”
Then there is the question of cost—there’s not a space program in history whose initial price tag wasn’t badly lowballed—to say nothing of maintaining that biennial launch schedule, to say nothing of the cabin fever that could soon enough set the settlers at one another’s throats. Jamestown may not have been a picnic, but when things got to be too much you could always go for a walk by the creek.
No creeks here, nor much of anything else either. Human beings may indeed colonize Mars one day, and it’s a very worthy goal. But as with any other kind of travel, the best part of going is often coming home.
New reports of further evidence for dark matter have been greatly exaggerated. Yesterday, researchers working with the Alpha Magnetic Spectrometer (AMS), a $2 billion cosmic ray detector attached to the International Space Station, reported their latest data on a supposed excess of high-energy positrons from space. They contended—at least in a press release—that the new results could offer new hints that they’ve detected particles of dark matter, the mysterious stuff whose gravity binds the galaxies. But several cosmic ray physicists say that the AMS data are still perfectly consistent with much more mundane explanations of the excess. And they doubt AMS alone will resolve the issue.
The leader of the AMS team, Nobel laureate Samuel Ting of the Massachusetts Institute of Technology in Cambridge, takes care to say that the new results do not prove that AMS has detected dark matter. But he also says the data lend more support to that interpretation than to some others. "The key statement is that we have not found a contradiction with the dark matter explanation," he says.
The controversy centers on AMS's measurement of a key ratio, the number of antimatter positrons to the sum of positrons and electrons. In April 2013, AMS confirmed early reports that as the energy of the particles increased above about 8 gigaelectron Volts (GeV), that ratio, or "positron fraction," increased, even as the individual fluxes of electrons and positrons were falling. That increase in the relative abundance of positrons could signal the presence of dark matter particles. According to many theories, if those particles collide, they would annihilate each other to produce electron-positron pairs. That would alter the balance of electrons and positrons among cosmic rays, as the usual source such as the cloudlike remnants of supernova explosions produce far more electrons than positrons.
However, that interpretation was hardly certain. Even before AMS released its measurement of the ratio, astrophysicists had argued that the excess positrons could potentially emanate from an undetected nearby pulsar. In November 2013, Eli Waxman, a theoretical astrophysicist at the Weizmann Institute of Science in Rehovot, Israel, and colleagues went even further. They argued that the excess positrons could come simply from the interactions of "primary" cosmic rays from supernova remnants with the interstellar medium. If so, then the positrons were just "secondary" rays and nothing to write home about.
However, AMS team researchers see two new features that are consistent with the dark matter interpretation, they reported online yesterday in Physical Review Letters. First, the AMS team now sees that after rising with energy, the positron fraction seems to level off and may begin to fall at an energy of 275 GeV, as would be expected if the excess were produced by colliding dark matter particles, as the original particles' mass would put an upper limit on the energy of the positron they spawned. AMS researchers say the leveling off would be consistent with a dark matter particle with a mass of 1 teraelectron volt (TeV). (Thanks to Albert Einstein’s famous equivalence of mass and energy, the two can be measured in the same units.)
Second, the AMS team measured the spectra of electrons and positrons individually. They found that the spectra have different shapes as energy increases. "It's really surprising that the electrons and positrons are so different," Ting says. And, he argues, the difference suggests that the positrons cannot be secondary cosmic rays produced by primary cosmic ray electrons, as such production should lead to similar spectra.
But some cosmic ray physicists aren't convinced. For example, in AMS's graph of the electron fraction, the error bars at the highest energies are large because the high-energy particles are so rare. And those uncertainties make it unclear whether the positron fraction really starts to drop, says Stéphane Coutu, a cosmic ray physicist at Pennsylvania State University, University Park. And even if the positron fraction does fall at energies higher than AMS reported, that wouldn't prove the positrons come from dark matter annihilations, Coutu says. Such a "cutoff" could easily arise in positrons from a pulsar, he says, if the spatial region in which the pulsar accelerates particles is of limited size. All told, the new results are "probably consistent with anything," Coutu says.
Similarly, Waxman questions Ting's claim that the new data suggest the positrons aren't simply secondary cosmic rays. If that were the case, then the electrons and positrons would be coming from different places and there would be no reason to expect their spectra to be similar, Waxman says. Moreover, he notes, AMS's measurement of the positron fraction seems to level out just at the limit that he and colleagues predicted would be the maximum achievable through secondary cosmic rays. So, in fact, the new data support the interpretation that the positrons are simply secondary cosmic rays, he says. "To me this is a very strong indication that we are seeing cosmic ray interactions.”
Will the argument ever end? AMS is scheduled to take data for 10 more years, which should enable scientists to whittle down the uncertainties and extend their reach toward higher energies, Ting says. "I think we should be able to reach 1 TeV with good statistics," he says, and that should be enough to eventually settle the dispute. But Gregory Tarlé, an astrophysicist at the University of Michigan, Ann Arbor, says, "I don't think that's a legitimate claim." Higher energy cosmic rays arrive at such a low rate that even quadrupling the data set would leave large statistical uncertainties, he says. So, Tarlé suspects, years from now the AMS results will likely look about as ambiguous they do now.
The leader of the AMS team, Nobel laureate Samuel Ting of the Massachusetts Institute of Technology in Cambridge, takes care to say that the new results do not prove that AMS has detected dark matter. But he also says the data lend more support to that interpretation than to some others. "The key statement is that we have not found a contradiction with the dark matter explanation," he says.
The controversy centers on AMS's measurement of a key ratio, the number of antimatter positrons to the sum of positrons and electrons. In April 2013, AMS confirmed early reports that as the energy of the particles increased above about 8 gigaelectron Volts (GeV), that ratio, or "positron fraction," increased, even as the individual fluxes of electrons and positrons were falling. That increase in the relative abundance of positrons could signal the presence of dark matter particles. According to many theories, if those particles collide, they would annihilate each other to produce electron-positron pairs. That would alter the balance of electrons and positrons among cosmic rays, as the usual source such as the cloudlike remnants of supernova explosions produce far more electrons than positrons.
However, that interpretation was hardly certain. Even before AMS released its measurement of the ratio, astrophysicists had argued that the excess positrons could potentially emanate from an undetected nearby pulsar. In November 2013, Eli Waxman, a theoretical astrophysicist at the Weizmann Institute of Science in Rehovot, Israel, and colleagues went even further. They argued that the excess positrons could come simply from the interactions of "primary" cosmic rays from supernova remnants with the interstellar medium. If so, then the positrons were just "secondary" rays and nothing to write home about.
However, AMS team researchers see two new features that are consistent with the dark matter interpretation, they reported online yesterday in Physical Review Letters. First, the AMS team now sees that after rising with energy, the positron fraction seems to level off and may begin to fall at an energy of 275 GeV, as would be expected if the excess were produced by colliding dark matter particles, as the original particles' mass would put an upper limit on the energy of the positron they spawned. AMS researchers say the leveling off would be consistent with a dark matter particle with a mass of 1 teraelectron volt (TeV). (Thanks to Albert Einstein’s famous equivalence of mass and energy, the two can be measured in the same units.)
Second, the AMS team measured the spectra of electrons and positrons individually. They found that the spectra have different shapes as energy increases. "It's really surprising that the electrons and positrons are so different," Ting says. And, he argues, the difference suggests that the positrons cannot be secondary cosmic rays produced by primary cosmic ray electrons, as such production should lead to similar spectra.
But some cosmic ray physicists aren't convinced. For example, in AMS's graph of the electron fraction, the error bars at the highest energies are large because the high-energy particles are so rare. And those uncertainties make it unclear whether the positron fraction really starts to drop, says Stéphane Coutu, a cosmic ray physicist at Pennsylvania State University, University Park. And even if the positron fraction does fall at energies higher than AMS reported, that wouldn't prove the positrons come from dark matter annihilations, Coutu says. Such a "cutoff" could easily arise in positrons from a pulsar, he says, if the spatial region in which the pulsar accelerates particles is of limited size. All told, the new results are "probably consistent with anything," Coutu says.
Similarly, Waxman questions Ting's claim that the new data suggest the positrons aren't simply secondary cosmic rays. If that were the case, then the electrons and positrons would be coming from different places and there would be no reason to expect their spectra to be similar, Waxman says. Moreover, he notes, AMS's measurement of the positron fraction seems to level out just at the limit that he and colleagues predicted would be the maximum achievable through secondary cosmic rays. So, in fact, the new data support the interpretation that the positrons are simply secondary cosmic rays, he says. "To me this is a very strong indication that we are seeing cosmic ray interactions.”
Will the argument ever end? AMS is scheduled to take data for 10 more years, which should enable scientists to whittle down the uncertainties and extend their reach toward higher energies, Ting says. "I think we should be able to reach 1 TeV with good statistics," he says, and that should be enough to eventually settle the dispute. But Gregory Tarlé, an astrophysicist at the University of Michigan, Ann Arbor, says, "I don't think that's a legitimate claim." Higher energy cosmic rays arrive at such a low rate that even quadrupling the data set would leave large statistical uncertainties, he says. So, Tarlé suspects, years from now the AMS results will likely look about as ambiguous they do now.
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The Future of Technology in 2015?
Excerpt from
cnet.com
The year gone by brought us more robots, worries about artificial intelligence, and difficult lessons on space travel. The big question: where's it all taking us?
Every year, we capture a little bit more of the future -- and yet the future insists on staying ever out of reach.
Consider space travel. Humans have been traveling beyond the atmosphere for more than 50 years now -- but aside from a few overnights on the moon four decades ago, we have yet to venture beyond low Earth orbit.
Or robots. They help build our cars and clean our kitchen floors, but no one would mistake a Kuka or a Roomba for the replicants in "Blade Runner." Siri, Cortana and Alexa, meanwhile, are bringing some personality to the gadgets in our pockets and our houses. Still, that's a long way from HAL or that lad David from the movie "A.I. Artificial Intelligence."
Self-driving cars? Still in low gear, and carrying some bureaucratic baggage that prevents them from ditching certain technology of yesteryear, like steering wheels.
And even when these sci-fi things arrive, will we embrace them? A Pew study earlier this year found that Americans are decidedly undecided. Among the poll respondents, 48 percent said they would like to take a ride in a driverless car, but 50 percent would not. And only 3 percent said they would like to own one.
"Despite their general optimism about the long-term impact of technological change," Aaron Smith of the Pew Research Center wrote in the report, "Americans express significant reservations about some of these potentially short-term developments" such as US airspace being opened to personal drones, robot caregivers for the elderly or wearable or implantable computing devices that would feed them information.
Let's take a look at how much of the future we grasped in 2014 and what we could gain in 2015.
Space travel: 'Space flight is hard'
In 2014, earthlings scored an unprecedented achievement in space exploration when the European Space Agency landed a spacecraft on a speeding comet, with the potential to learn more about the origins of life. No, Bruce Willis wasn't aboard. Nobody was. But when the 220-pound Philae lander, carried to its destination by the Rosetta orbiter, touched down on comet 67P/Churyumov-Gerasimenko on November 12, some 300 million miles from Earth, the celebration was well-earned.A shadow quickly fell on the jubilation, however. Philae could not stick its first landing, bouncing into a darker corner of the comet where its solar panels would not receive enough sunlight to charge the lander's batteries. After two days and just a handful of initial readings sent home, it shut down. For good? Backers have allowed for a ray of hope as the comet passes closer to the sun in 2015. "I think within the team there is no doubt that [Philae] will wake up," lead lander scientist Jean-Pierre Bibring said in December. "And the question is OK, in what shape? My suspicion is we'll be in good shape."
The trip for NASA's New Horizons spacecraft has been much longer: 3 billion miles, all the way to Pluto and the edge of the solar system. Almost nine years after it left Earth, New Horizons in early December came out of hibernation to begin its mission: to explore "a new class of planets we've never seen, in a place we've never been before," said project scientist Hal Weaver. In January, it will begin taking photos and readings of Pluto, and by mid-July, when it swoops closest to Pluto, it will have sent back detailed information about the dwarf planet and its moon, en route to even deeper space.
Also in December, NASA made a first test spaceflight of its Orion capsule on a quick morning jaunt out and back, to just over 3,600 miles above Earth (or approximately 15 times higher than the International Space Station). The distance was trivial compared to those those traveled by Rosetta and New Horizons, and crewed missions won't begin till 2021, but the ambitions are great -- in the 2030s, Orion is expected to carry humans to Mars.
In late March 2015, two humans will head to the ISS to take up residence for a full year, in what would be a record sleepover in orbit. "If a mission to Mars is going to take a three-year round trip," said NASA astronaut Scott Kelly, who will be joined in the effort by Russia's Mikhail Kornienko, "we need to know better how our body and our physiology performs over durations longer than what we've previously on the space station investigated, which is six months."
There were more sobering moments, too, in 2014. In October, Virgin Galactic's sleek, experimental SpaceShipTwo, designed to carry deep-pocketed tourists into space, crashed in the Mojave Desert during a test flight, killing one test pilot and injuring the other. Virgin founder Richard Branson had hoped his vessel would make its first commercial flight by the end of this year or in early 2015, and what comes next remains to be seen. Branson, though, expressed optimism: "Space flight is hard -- but worth it," he said in a blog post shortly after the crash, and in a press conference, he vowed "We'll learn from this, and move forward together." Virgin Galactic could begin testing its next spaceship as soon as early 2015.
The crash of SpaceShipTwo came just a few days after the explosion of an Orbital Sciences rocket lofting an unmanned spacecraft with supplies bound for the International Space Station. And in July, Elon Musk's SpaceX had suffered the loss of one of its Falcon 9 rockets during a test flight. Musk intoned, via Twitter, that "rockets are tricky..."
Still, it was on the whole a good year for SpaceX. In May, it unveiled its first manned spacecraft, the Dragon V2, intended for trips to and from the space station, and in September, it won a $2.6 billion contract from NASA to become one of the first private companies (the other being Boeing) to ferry astronauts to the ISS, beginning as early as 2017. Oh, and SpaceX also has plans to launch microsatellites to establish low-cost Internet service around the globe, saying in November to expect an announcement about that in two to three months -- that is, early in 2015.
One more thing to watch for next year: another launch of the super-secret X-37B space place to do whatever it does during its marathon trips into orbit. The third spaceflight of an X-37B -- a robotic vehicle that, at 29 feet in length, looks like a miniature space shuttle -- ended in October after an astonishing 22 months circling the Earth, conducting "on-orbit experiments."
Self-driving cars: Asleep at what wheel?
Spacecraft aren't the only vehicles capable of autonomous travel -- increasingly, cars are, too. Automakers are toiling toward self-driving cars, and Elon Musk -- whose name comes up again and again when we talk about the near horizon for sci-fi tech -- says we're less than a decade away from capturing that aspect of the future. In October, speaking in his guise as founder of Tesla Motors, Musk said: "Like maybe five or six years from now I think we'll be able to achieve true autonomous driving where you could literally get in the car, go to sleep and wake up at your destination." (He also allowed that we should tack on a few years after that before government regulators give that technology their blessing.)Google has long been working on its own robo-cars, and until this year, that meant taking existing models -- a Prius here, a Lexus there -- and buckling on extraneous gear. Then in May, the tech titan took the wraps off a completely new prototype that it had built from scratch. (In December, it showed off the first fully functional prototype.) It looked rather like a cartoon car, but the real news was that there was no steering wheel, gas pedal or brake pedal -- no need for human controls when software and sensors are there to do the work.
Or not so fast. In August, California's Department of Motor Vehicles declared that Google's test vehicles will need those manual controls after all -- for safety's sake. The company agreed to comply with the state's rules, which went into effect in September, when it began testing the cars on private roads in October.
Regardless of who's making your future robo-car, the vehicle is going to have to be not just smart, but actually thoughtful. It's not enough for the car to know how far it is from nearby cars or what the road conditions are. The machine may well have to make no-win decisions, just as human drivers sometimes do in instantaneous, life-and-death emergencies. "The car is calculating a lot of consequences of its actions," Chris Gerdes, an associate professor of mechanical engineering, said at the Web Summit conference in Dublin, Ireland, in November. "Should it hit the person without a helmet? The larger car or the smaller car?"
Robots: Legging it out
So when do the robots finally become our overlords? Probably not in 2015, but there's sure to be more hand-wringing about both the machines and the artificial intelligence that could -- someday -- make them a match for homo sapiens. At the moment, the threat seems more mundane: when do we lose our jobs to a robot?The inquisitive folks at Pew took that very topic to nearly 1,900 experts, including Vint Cerf, vice president at Google; Web guru Tim Bray; Justin Reich of Harvard University's Berkman Center for Internet & Society; and Jonathan Grudin, principal researcher at Microsoft. According to the resulting report, published in August, the group was almost evenly split -- 48 percent thought it likely that, by 2025, robots and digital agents will have displaced significant numbers of blue- and white-collar workers, perhaps even to the point of breakdowns in the social order, while 52 percent "have faith that human ingenuity will create new jobs, industries, and ways to make a living, just as it has been doing since the dawn of the Industrial Revolution."
Still, for all of the startling skills that robots have acquired so far, they're often not all there yet. Here's some of what we saw from the robot world in 2014:
Teamwork: Researchers at the École Polytechnique Fédérale De Lausanne in May showed off their "Roombots," cog-like robotic balls that can join forces to, say, help a table move across a room or change its height.
A sense of balance: We don't know if Boston Dynamics' humanoid Atlas is ready to trim bonsai trees, but it has learned this much from "The Karate Kid" (the original from the 1980s) -- it can stand on cinder blocks and hold its balance in a crane stance while moving its arms up and down.
Catlike jumps: MIT's cheetah-bot gets higher marks for locomotion. Fed a new algorithm, it can run across a lawn and bound like a cat. And quietly, too. "Our robot can be silent and as efficient as animals. The only things you hear are the feet hitting the ground," MIT's Sangbae Kim, a professor of mechanical engineering, told MIT News. "This is kind of a new paradigm where we're controlling force in a highly dynamic situation. Any legged robot should be able to do this in the future."
Sign language: Toshiba's humanoid Aiko Chihira communicated in Japanese sign language at the CEATEC show in October. Her rudimentary skills, limited for the moment to simple messages such as signed greetings, are expected to blossom by 2020 into areas such as speech synthesis and speech recognition.
Dance skills: Robotic pole dancers? Tobit Software brought a pair, controllable by an Android smartphone, to the Cebit trade show in Germany in March. More lifelike was the animatronic sculpture at a gallery in New York that same month -- but what was up with that witch mask?
Emotional ambition: Eventually, we'll all have humanoid companions -- at least, that's always been one school of thought on our robotic future. One early candidate for that honor could be Pepper, from Softbank and Aldebaran Robotics, which say the 4-foot-tall Pepper is the first robot to read emotions. This emo-bot is expected to go on sale in Japan in February.
Ray guns: Ship shape
Damn the photon torpedoes, and full speed ahead. That could be the motto for the US Navy, which in 2014 deployed a prototype laser weapon -- just one -- aboard a vessel in the Persian Gulf. Through some three months of testing, the device "locked on and destroyed the targets we designated with near-instantaneous lethality," Rear Adm. Matthew L. Klunder, chief of naval research, said in a statement. Those targets were rather modest -- small objects mounted aboard a speeding small boat, a diminutive Scan Eagle unmanned aerial vehicle, and so on -- but the point was made: the laser weapon, operated by a controller like those used for video games, held up well, even in adverse conditions.Artificial intelligence: Danger, Will Robinson?
What happens when robots and other smart machines can not only do, but also think? Will they appreciate us for all our quirky human high and low points, and learn to live with us? Or do they take a hard look at a species that's run its course and either turn us into natural resources, "Matrix"-style, or rain down destruction?Musk himself more than once in 2014 invoked the likes of the "Terminator" movies and the "scary outcomes" that make them such thrilling popcorn fare. Except that he sees a potentially scary reality evolving. In an interview with CNBC in June, he spoke of his investment in AI-minded companies like Vicarious and Deep Mind, saying: "I like to just keep an eye on what's going on with artificial intelligence. I think there is potentially a dangerous outcome."
He has put his anxieties into some particularly colorful phrases. In August, for instance, Musk tweeted that AI is "potentially more dangerous than nukes." And in October, he said this at a symposium at MIT: "With artificial intelligence, we are summoning the demon. ... You know all those stories where there's the guy with the pentagram and the holy water and he's like... yeah, he's sure he can control the demon, [but] it doesn't work out."
Musk has a kindred spirit in Stephen Hawking. The physicist allowed in May that AI could be the "biggest event in human history," and not necessarily in a good way. A month later, he was telling John Oliver, on HBO's "Last Week Tonight," that "artificial intelligence could be a real danger in the not too distant future." How so? "It could design improvements to itself and outsmart us all."
But Google's Eric Schmidt, is having none of that pessimism. At a summit on innovation in December, the executive chairman of the far-thinking tech titan -- which in October teamed up with Oxford University to speed up research on artificial intelligence -- said that while our worries may be natural, "they're also misguided."