l heard from a computer wizz about 8 - 9 years ago that crystals were going to be the next big thing in computing. He just didn't know how they were going to work, but he was convinced.
Scientists "freeze" light inside a crystal for one minute
More info here: http://www.gizmag.com/stopping-light-inside-crystal/28610/
I'm not going to attempt to read that. Can you tell me, after they've stopped it, can they start it again? I mean re-start the same light they've stopped? And when it's stopped, what does it look like? If it's not moving, how is it still light? And don't I stop light every time I turn off the light switch at night?
OK, they're only half-serious questions, but to me a statement that someone has stopped light inside a crystal is basically meaningless.
When people talk about the speed of light, what they really mean is "the speed of light in vacuumn/air/glass/water/whatever". The speed inside that medium is given by c/n, where c is the speed of light in a vacuumn (3x10^8 m/s) and n is the refractive index of the medium. The refractive index of vacuumn is 1, air is a bit over 1, water is 1.33, glass is about 1.5, and diamond is about 2.6. Diamond has one of the highest naturally occuring refractive indices, meaning that light still moves at over 10,000 km/s.
There are certain exotic materials though where you can change the refractive index, with either electricity, or another beam of light. That's basically what's going on here. It's not really that they've stopped light, which is probably why frozen is in inverted commas, but they've just made it very slow.
So, to answer your questions:
1) Yes, you just remove the second beam.
2) It's still light. It still "looks" the same. It's just not moving.
3) No. You creating an absence of light, which is completely different.
Tell me when it's on the shelf.
Then give me a discount.
Light generated in the middle of the sun takes thousands of years to get out.
True, but the neutrinos come straight through, and at the speed of light (in a vacuum). Amazing things, neutrinos. They should change c to be the speed of neutrinos.
Scientists "freeze" light inside a crystal for one minute
More info here: http://www.gizmag.com/stopping-light-inside-crystal/28610/
I'm not going to attempt to read that. Can you tell me, after they've stopped it, can they start it again? I mean re-start the same light they've stopped? And when it's stopped, what does it look like? If it's not moving, how is it still light? And don't I stop light every time I turn off the light switch at night?
OK, they're only half-serious questions, but to me a statement that someone has stopped light inside a crystal is basically meaningless.
Light can be used as a medium for containing data. A good example is optical fibre cable, such as what they're using for the NBN, which is essentially a long string of glass through which light can travel. It's an extremely efficient means of transferring data.
Now if you manage to find an object that can trap (ie. contain so that it can be recovered) light, then you have a means of storing vast amounts of data that can be recovered and transferred elsewhere incredibly quickly.
Good news, everyone!
So no chance of this...
please link articles properly people.
cut and paste the article and provide the link for authentication and credit puposes.
Scientists "freeze" light inside a crystal for one minute
More info here: http://www.gizmag.com/stopping-light-inside-crystal/28610/
I'm not going to attempt to read that. Can you tell me, after they've stopped it, can they start it again? I mean re-start the same light they've stopped? And when it's stopped, what does it look like? If it's not moving, how is it still light? And don't I stop light every time I turn off the light switch at night?
OK, they're only half-serious questions, but to me a statement that someone has stopped light inside a crystal is basically meaningless.
When people talk about the speed of light, what they really mean is "the speed of light in vacuumn/air/glass/water/whatever". The speed inside that medium is given by c/n, where c is the speed of light in a vacuumn (3x10^8 m/s) and n is the refractive index of the medium. The refractive index of vacuumn is 1, air is a bit over 1, water is 1.33, glass is about 1.5, and diamond is about 2.6. Diamond has one of the highest naturally occuring refractive indices, meaning that light still moves at over 10,000 km/s.
There are certain exotic materials though where you can change the refractive index, with either electricity, or another beam of light. That's basically what's going on here. It's not really that they've stopped light, which is probably why frozen is in inverted commas, but they've just made it very slow.
So, to answer your questions:
1) Yes, you just remove the second beam.
2) It's still light. It still "looks" the same. It's just not moving.
3) No. You creating an absence of light, which is completely different.
That or put it behind any given Toyota at any given set of traffic lights (ON GREEN! FFFUUUUUAAAA....) in Box Hill, ever.
That or put it behind any given Toyota at any given set of traffic lights (ON GREEN! FFFUUUUUAAAA....) in Box Hill, ever.When people talk about the speed of light, what they really mean is "the speed of light in vacuumn/air/glass/water/whatever". The speed inside that medium is given by c/n, where c is the speed of light in a vacuumn (3x10^8 m/s) and n is the refractive index of the medium. The refractive index of vacuumn is 1, air is a bit over 1, water is 1.33, glass is about 1.5, and diamond is about 2.6. Diamond has one of the highest naturally occuring refractive indices, meaning that light still moves at over 10,000 km/s.Scientists "freeze" light inside a crystal for one minute
More info here: http://www.gizmag.com/stopping-light-inside-crystal/28610/
I'm not going to attempt to read that. Can you tell me, after they've stopped it, can they start it again? I mean re-start the same light they've stopped? And when it's stopped, what does it look like? If it's not moving, how is it still light? And don't I stop light every time I turn off the light switch at night?
OK, they're only half-serious questions, but to me a statement that someone has stopped light inside a crystal is basically meaningless.
There are certain exotic materials though where you can change the refractive index, with either electricity, or another beam of light. That's basically what's going on here. It's not really that they've stopped light, which is probably why frozen is in inverted commas, but they've just made it very slow.
So, to answer your questions:
1) Yes, you just remove the second beam.
2) It's still light. It still "looks" the same. It's just not moving.
3) No. You creating an absence of light, which is completely different.
Obviously never owned, used a trade vehicle have you. Nothing is better than a Toyota Hilux
Obviously never owned, used a trade vehicle have you. Nothing is better than a Toyota Hilux
Nothing was better than a Hi Lux. There are a few now. The new Ford Ranger would eat a Hi Lux for dinner.
But that said, Toyota make a ■■■■■■ good, strong, reliable car. It's just that they are as bland as it is possible to be. And as boring as bat ■■■■.
Oh RORDon't be mean to Toyota drivers.That or put it behind any given Toyota at any given set of traffic lights (ON GREEN! FFFUUUUUAAAA....) in Box Hill, ever.When people talk about the speed of light, what they really mean is "the speed of light in vacuumn/air/glass/water/whatever". The speed inside that medium is given by c/n, where c is the speed of light in a vacuumn (3x10^8 m/s) and n is the refractive index of the medium. The refractive index of vacuumn is 1, air is a bit over 1, water is 1.33, glass is about 1.5, and diamond is about 2.6. Diamond has one of the highest naturally occuring refractive indices, meaning that light still moves at over 10,000 km/s.Scientists "freeze" light inside a crystal for one minute
More info here: http://www.gizmag.com/stopping-light-inside-crystal/28610/
I'm not going to attempt to read that. Can you tell me, after they've stopped it, can they start it again? I mean re-start the same light they've stopped? And when it's stopped, what does it look like? If it's not moving, how is it still light? And don't I stop light every time I turn off the light switch at night?
OK, they're only half-serious questions, but to me a statement that someone has stopped light inside a crystal is basically meaningless.
There are certain exotic materials though where you can change the refractive index, with either electricity, or another beam of light. That's basically what's going on here. It's not really that they've stopped light, which is probably why frozen is in inverted commas, but they've just made it very slow.
So, to answer your questions:
1) Yes, you just remove the second beam.
2) It's still light. It still "looks" the same. It's just not moving.
3) No. You creating an absence of light, which is completely different.
They're probably company cars, as I can't imagine anyone choosing to drive them.
Not their fault the shitboxes have worse pick-up than a turtle trying to go uphill on an oil slick over ice.
They are pretty exciting when you take the turbo diesel off road. The ranger is nice though, and I would not knock one back, I like the VW amarok too.
there's hope for a few Blitzers yet..
Web edition: August 28, 2013
Print edition: September 21, 2013; Vol.184 #6 (p. 5)
Largely left to their own devices, human stem cells knitted themselves into tissue with a multitude of brain structures and specialized cadres of neurons in a form reminiscent of the brain of a nine-week-old fetus, scientists report August 28 in Nature.
The tissue doesn‘t approach the dizzying complexity of the human brain. Yet these tiny neural balls, each no bigger than a BB pellet, represent the most complex brain structure grown in a lab to date, researchers say. The new work could provide an unprecedented window into the early stages of human brain development, a simple way to test pharmaceuticals on human brain tissue and a way to study the brain defects of individual patients, the study authors suggest.
“They‘ve done something very remarkable,†says Flora Vaccarino of Yale University.
After about two months of growing in a nutrient broth, the cells specialized into neurons that populated distinct, recognizable parts of the developing brain, such as the hippocampus, retina and choroid plexus, which produces cerebrospinal fluid in the brain.
The tissue clumps also had discrete parts of the cerebral cortex, the outer sheet of the human brain that‘s responsible for advanced thought processes. Other properties of the human brain held true, too: Many of the neurons were actively firing off electrical messages, experiments revealed. Select groups of young neurons seemed to have migrated to a different part of the organoid, a process that helps populate the brain with neurons. And like the brain, the tissue had a rich population of a specialized stem cell called radial glial stem cells. These cells kept neuron numbers growing.
Called “cerebral organoids†by study coauthors Madeline Lancaster and Jürgen Knoblich of the Austrian Academy of Science in Vienna, the tiny lab-grown tissues could have big implications for brain science. Already, by growing a personalized organoid with cells from a patient, the researchers have learned about microcephaly, a developmental disorder marked by a small brain.
“There is enormous potential there,†says neuroscientist Ed Lein of the Allen Institute for Brain Science in Seattle.
The organoid-growing process begins with human stem cells, taken either directly from an embryo or from adult skin samples that have been reprogrammed to an embryo-like state. These cells can grow into any tissue in the human body. To make them into a cerebral organoid, the researchers let the cells grow for a few days in a dish, and then moved them into a broth that encourages the growth of neuroectoderm tissue, the kind that ultimately creates the brain. After that, the researchers injected these cells into a drop of gel that serves as a scaffold for the cells to grow on. In the final move, the gel droplets were transferred to spinning flasks that held nutrients.
This last step was crucial, the researchers found: The spinning motion distributed oxygen and nutrients to all of the cells in the organoid. Without it, cells, especially those in the center, would starve and die.
After about two months, the organoids had pushed past the boundary of their gel droplets, reaching a diameter of about 4 millimeters.
So far, the researchers have grown hundreds of these cerebral organoids and the oldest is about a year old. In the oldest ones, the cells are still alive but have stopped dividing, Lancaster says. The organoids reach maximum size after about two months; any larger and the cells on the interior would not get enough nutrients and oxygen, she says.
One of the most remarkable aspects of the work is that the organoids formed these complex, brainlike structures with little from researchers, Lein says. “The biggest thing for me is realizing that most of the information for generating a brain is intrinsic,†he says. “These cells carry enough information to generate a brain.â€
That means that cells from different people can easily be used to grow very different sorts of brains. As part of their study, Lancaster, Knoblich and colleagues grew a personalized organoid using cells from the skin of a patient with microcephaly. Lancaster says she immediately saw that the organoid was smaller than usual.
Microcephaly has been difficult to study. But with the microcephaly organoid, the researchers figured out why the brains were smaller. Neuron-producing radial glial cells were stopping their job too early and disappearing, the researchers found. This early termination could ultimately result in too few neurons, a situation that might also happen in microcephaly. These organoids could offer insight into more complex disorders rooted in brain development, too, such as schizophrenia and autism, says Knoblich.
Of course, these organoids differ from the brain in many ways. Unlike the brain‘s organized structure, regions in the organoids were arranged haphazardly. The neurons made connections, but probably not meaningful ones like those in the human brain. And important support systems, such as blood vessels, were absent.
“If you look at our organoid as a whole, it is not a brain,†Knoblich says. Nonetheless, the system is a useful approximation.
https://www.simonsfoundation.org/qua...antum-physics/
Physicists have discovered a jewel-like geometric object that dramatically simplifies calculations of particle interactions and challenges the notion that space and time are fundamental components of reality.<br>
“This is completely new and very much simpler than anything that has been done before,†said Andrew Hodges, a mathematical physicist at Oxford University who has been following the work.<br>
The revelation that particle interactions, the most basic events in nature, may be consequences of geometry significantly advances a decades-long effort to reformulate quantum field theory, the body of laws describing elementary particles and their interactions. Interactions that were previously calculated with mathematical formulas thousands of terms long can now be described by computing the volume of the corresponding jewel-like “amplituhedron,†which yields an equivalent one-term expression.
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https://www.simonsfoundation.org/qua...antum-physics/
Physicists have discovered a jewel-like geometric object that dramatically simplifies calculations of particle interactions and challenges the notion that space and time are fundamental components of reality.
“This is completely new and very much simpler than anything that has been done before,†said Andrew Hodges, a mathematical physicist at Oxford University who has been following the work.
The revelation that particle interactions, the most basic events in nature, may be consequences of geometry significantly advances a decades-long effort to reformulate quantum field theory, the body of laws describing elementary particles and their interactions. Interactions that were previously calculated with mathematical formulas thousands of terms long can now be described by computing the volume of the corresponding jewel-like “amplituhedron,†which yields an equivalent one-term expression.
This is all very well but we have to settle the argument about whether string theory has 10 or 11 dimensions first.
https://www.simonsfoundation.org/qua...antum-physics/
Physicists have discovered a jewel-like geometric object that dramatically simplifies calculations of particle interactions and challenges the notion that space and time are fundamental components of reality.
“This is completely new and very much simpler than anything that has been done before,†said Andrew Hodges, a mathematical physicist at Oxford University who has been following the work.
The revelation that particle interactions, the most basic events in nature, may be consequences of geometry significantly advances a decades-long effort to reformulate quantum field theory, the body of laws describing elementary particles and their interactions. Interactions that were previously calculated with mathematical formulas thousands of terms long can now be described by computing the volume of the corresponding jewel-like “amplituhedron,†which yields an equivalent one-term expression.
This is all very well but we have to settle the argument about whether string theory has 10 or 11 dimensions first.
M THEORY FOR LIFE, DAWG
Nuclear fusion milestone passed at US lab
By Paul RinconScience Editor, BBC News websiteThe achievement is the first of its kind anywhere in the world
Continue reading the main story Related StoriesResearchers at a US lab have passed a crucial milestone on the way to their ultimate goal of achieving self-sustaining nuclear fusion.
Harnessing fusion - the process that powers the Sun - could provide an unlimited and cheap source of energy.
But to be viable, fusion power plants would have to produce more energy than they consume, which has proven elusive.
Now, a breakthrough by scientists at the National Ignition Facility (NIF) could boost hopes of scaling up fusion.
NIF, based at Livermore in California, uses 192 beams from the world's most powerful laser to heat and compress a small pellet of hydrogen fuel to the point where nuclear fusion reactions take place.
The BBC understands that during an experiment in late September, the amount of energy released through the fusion reaction exceeded the amount of energy being absorbed by the fuel - the first time this had been achieved at any fusion facility in the world.
This is a step short of the lab's stated goal of "ignition", where nuclear fusion generates as much energy as the lasers supply. This is because known "inefficiencies" in different parts of the system mean not all the energy supplied through the laser is delivered to the fuel.
Continue reading the main story Nuclear fusion at NIF
- 192 laser beams are focused through holes in a target container called a hohlraum
- Inside the hohlraum is a tiny pellet containing an extremely cold, solid mixture of hydrogen isotopes
- Lasers strike the hohlraum's walls, which in turn radiate X-rays
- X-rays strip material from the outer shell of the fuel pellet, heating it up to millions of degrees
- If the compression of the fuel is high enough and uniform enough, nuclear fusion can result
But the latest achievement has been described as the single most meaningful step for fusion in recent years, and demonstrates NIF is well on its way towards the coveted target of ignition and self-sustaining fusion.
For half a century, researchers have strived for controlled nuclear fusion and been disappointed. It was hoped that NIF would provide the breakthrough fusion research needed.
In 2009, NIF officials announced an aim to demonstrate nuclear fusion producing net energy by 30 September 2012. But unexpected technical problems ensured the deadline came and went; the fusion output was less than had originally been predicted by mathematical models.
Soon after, the $3.5bn facility shifted focus, cutting the amount of time spent on fusion versus nuclear weapons research - which was part of the lab's original mission.
However, the latest experiments agree well with predictions of energy output, which will provide a welcome boost to ignition research at NIF, as well as encouragement to advocates of fusion energy in general.
It is markedly different from current nuclear power, which operates through splitting atoms - fission - rather than squashing them together in fusion.
NIF, based at the Lawrence Livermore National Laboratory, is one of several projects around the world aimed at harnessing fusion. They include the multi-billion-euro ITER facility, currently under construction in Cadarache, France.
However, ITER will take a different approach to the laser-driven fusion at NIF; the Cadarache facility will use magnetic fields to contain the hot fusion fuel - a concept known as magnetic confinement.
