Tag Archives: Theory of Relativity

einstein_learning

Albert Einstein’s secret to learning anything

einstein_learning

In 1915, a thirty-six year old Albert Einstein had just finished completing the two-page masterpiece that would revolutionize modern physics and catapult the struggling physicist into international fame and glory – the theory of general relativity. A hundred years since the seminal paper was published, we celebrate Einstein by presenting one of his most enlightening correspondence.

On November 4, having just finished writing his landmark paper, Einstein wrote this most heartfelt and considerate letter to his then 11-year old son Hans Albert, who was living with his estranged mother and little brother, Eduard “Tete” Einstein, in Vienna.

The letter (featured below), like most of Einstein’s correspondence, shines of fatherly wisdom and speaks of something that most people should always consider: how to learn.

My dear Albert,

Yesterday I received your dear letter and was very happy with it. I was already afraid you wouldn’t write to me at all any more. You told me when I was in Zurich, that it is awkward for you when I come to Zurich. Therefore I think it is better if we get together in a different place, where nobody will interfere with our comfort. I will in any case urge that each year we spend a whole month together, so that you see that you have a father who is fond of you and who loves you. You can also learn many good and beautiful things from me, something another cannot as easily offer you. What I have achieved through such a lot of strenuous work shall not only be there for strangers but especially for my own boys. These days I have completed one of the most beautiful works of my life, when you are bigger, I will tell you about it.

I am very pleased that you find joy with the piano. This and carpentry are in my opinion for your age the best pursuits, better even than school. Because those are things which fit a young person such as you very well. Mainly play the things on the piano which please you, even if the teacher does not assign those. That is the way to learn the most, that when you are doing something with such enjoyment that you don’t notice that the time passes. I am sometimes so wrapped up in my work that I forget about the noon meal. . . .

Be with Tete kissed by your

Papa.

Regards to Mama.

Einstein wrote hundreds of letters to his friends and collaborators, some of which can now be found in private collections at places like the Raab Collection. Some sell for thousands of dollars at auctions.

 

`Relatively Simple

Book review: “Einstein Relatively Simple: Our Universe Revealed”

`Relatively Simple

Einstein Relatively Simple: Our Universe Revealed
By Ira Mark Egdall
World Scientific Publishing Company, 300pp | Buy on Amazon

In 1687, Isaac Newton published his groundbreaking Philosophiæ Naturalis Principia Mathematica, where he outlined his Three Laws of Motion and law of Universal Gravitation. For more than 300 years these were accepted without question because they predicted sufficiently accurate how mechanical systems would behave. This was the status quo until the beginning of the last century. That’s until Albert Einstein’s seminal papers revolutionized the way scientists think about space and time.

Albert Einstein shook the foundations of physics with the introduction of his Special Theory of Relativity in 1905, and his General Theory of Relativity in 1915. The first paper showed that Newton’s Three Laws of Motion were only approximately correct, breaking down when velocities approached that of light. The second showed  that Newton’s Law of Gravitation was also only approximately correct, since gravity is directly influenced by how strong gravitational fields are.

Today, Einstein is perhaps the most easily recognized scientist in history. His most famous equation E=mc2, which proves the equivalence of mass and energy, is extremely rampant in popular culture, encountered everywhere from TV cartoons to etched baseball caps. Yet, ask most people who share Einstein’s quotes on facebook what does E=mc2 stand for or what his theories of relativity imply, and they’ll shrug. “Einstein’s a genius – I’ll never understand his work,” some might wrongfully say. Well, here’s an Einstein quote to get you started “It’s not that I’m so smart, it’s just that I stay with problems longer.”

However, to understand Einstein’s most fundamental theorems you need not experience the same mental strain Einstein went through. Countless books have been written that seek to explain special and general relativity to the general public, and I’ve yet to found a more reader friendly book on relativity than Ira Mark Egdall’s “Einstein Relatively Simple: Our Universe Revealed.” The whole book is riddled with real life examples that almost anyone can relate to, all set in a humorous tone. Most of all, the language is so clear that even a fifth grader will come to understand relativity – in fact, Egdall hints in one of his chapters how primary school kids will be studying Einstein’s theories just as they do Newton’s today. The intellectual gap between the two views, one classical, the other relativistic, lies more in perception, than in genuine intellectual stress. It’s all relative!

Of course, you’ll find some equations, but they’re well explained physically such that laymen might grasp the essence without becoming lost in the mathematical details. Seasoned readers who aren’t afraid of math and hardcore physics have quite a few annex sections where they can delve deeper into Einstein’s process.

Understanding relativity becomes easier if we understand Einstein too. Filling his shoes, if just for a brief moment, brings us closer to his process, his creative thinking and ultimately grants access to the well of information the great physicist revealed to the world. Egdall follows these thoughts and is sure to fill is on some of Einstein’s most important personal turning points, whether it was his relationship with his parents or wife, or his conflictual episodes with conventional education and academia. All without turning the book into a 2nd rate biography. It stays true to itself – it’s a book on relativity!

All in all, I’d recommend this book to anyone who wants to grasp some of the most important works in modern physics, for ultimately without relativity we would never had learned about the Big Bang, black holes and our view of the universe would have been significantly poorer.

Pulsars with black holes could hold the ‘holy grail’ of gravity

Pulsars and black holes, two of the most enigmatic celestial bodies in the Universe may actually hold the key to understanding how Einstein’s theory of relativity and gravity interact.

Artistic depiction of a pulsar and the emitted radiation. Image via National Radio Astronomy Observatory.

A pulsar is a highly magnetized, rotating neutron star that emits a beam of electromagnetic radiation. Pulsars are from when a star that turns becomes a supernova and then collapses into a neutron star; the neutron star maintains its angular momentum, but because it has lost most of its mass, it starts to spin incredibly fast –  usually between a 2 and 50 times per second! The longest known spin period is just over 8 seconds. Due to this spin, pulsars are also excellent time keepers, as they emit intermittent light at regular intervals. Now, researchers believe that pulsars could be used to put Einstein’s theory of relativity to the test, especially if a pulsar would be found in the vicinity of a black hole. The only problem is that so far, this scenario has never been encountered.

“Pulsars act as very precise timekeepers, such that any deviation in their pulses can be detected,” Diego F. Torres, ICREA researcher from the Institute of Space Sciences (IEEC-CSIC), explains. “If we compare the actual measurements with the corrections to the model that we have to use in order for the predictions to be correct, we can set limits or directly detect the deviation from the base theory.”

Deviations mentioned by Torres occur when there is an object with significant mass close to the pulsar; in the lack of a black hole, that’s usually a white dwarf or another neutron star. By analyzing the interactions between pulsar-white dwarf or pulsar-neutron star interactions, astrophysicists can put not only the theory of gravity, but also Einstein’s relativity to the test. In the theory of relativity, the gravitational movement of a body results from the accelerating force exerted by the gravitational fields and nothing else. It is relatively constant in direction and magnitude. In other words, if you set up a free-fall experiment in a laboratory, the results will be independent on where the laboratory is in space and time and will depend only on the gravitational force(s).

This has been confirmed by previous observations, but in a new study, Torres and his colleague Manjari Bagchi argue that if you really want to put this idea to the test, you need to find a pulsar-black hole system; all that’s left now… is to actually find one.

Within the carefully sculpted waveguide, (left) light waves typically overlap to make a banded pattern (middle). However, depending on the width of the waveguide, waves of a certain wavelength travel infinitely fast, making the whole waveguide light up. (c) AMOLF and University of Pennsylvania

Nanodevice lets light waves travel infinitely fast. Theory of Relativity still in place

A team of international physicists have made a nano-sized device which can allow the phase velocities of certain wave of visible light travel infinitely fast. No, this doesn’t translate into instant communication, nor does it mean that Einstein’s Theory of Relativity has been broken. It’s safe and sound. Read on, however, about the potential uses this sort of experiment may render as well as the process that produced these findings.

In vacuum, light travels at 300,000 kilometers/second. If it hits a refracting medium like water or glass, light is bent and travels slower. The ratio between the velocity of light in vacuum and that in the refracting medium is known as the refraction index. If light travels through vacuum, this index is equal to 1, else it’s greater than one.

For some years now, various scientists have claimed they’ve developed negative refraction index mediums, as in smaller than 1. A decade or so ago, John Pendry of London’s Imperial College published a paper proposing a “perfect lens” with a negative refractive index. Light wavelengths normally limit lens resolution, but Pendry’s perfect lens suffered no such limitations. Besides,  in 2006, Pendry collaborated with David Smith at Duke University to develop a theory to hide an arbitrary object from electromagnetic fields. Realizations of this concept have succeeded at radar and at visible wavelengths.

Pendry’s paper was heavily criticized at the time of publishing, in the same year, physicists David Smith and Sheldon Schultz of the University of California at San Diego measured the transmission angle of microwaves they sent through an unusual grid of thin copper wires and split copper rings mounted on a circuit board. These measurements, they claimed, showed negative refraction for the first time.

A zero refraction index of light

Now, Albert Polman, a physicist at the FOM Institute for Atomic and Molecular Physics in Amsterdam; Nader Engheta, an electrical engineer at the University of Pennsylvania; and colleagues have pulled out something similar and entirely different at the time – a medium with a refraction index of 0! This means light of particular wavelengths can travel infinitely fast.

Within the carefully sculpted waveguide, (left) light waves typically overlap to make a banded pattern (middle). However, depending on the width of the waveguide, waves of a certain wavelength travel infinitely fast, making the whole waveguide light up. (c) AMOLF and University of Pennsylvania

Within the carefully sculpted waveguide, (left) light waves typically overlap to make a banded pattern (middle). However, depending on the width of the waveguide, waves of a certain wavelength travel infinitely fast, making the whole waveguide light up. (c) AMOLF and University of Pennsylvania

The device in question is comprised of a rectangular bar made out of insulating silicon dioxide, 85 nanometers thick and 2000 nanometers long, surrounded by conducing silver that blocks light. The resulting set-up  is called a waveguide since it conveys light. The researchers performed multiple experiments in which the width of the silicon dioxide ranged from 120 to 400 nanometers.

Because of its extremely compact size, light behaves in an odd manner inside the device. Short-wavelength light bounces back and forth between the ends of the guide, and the peaks and troughs of the counter-propagating light waves overlap to create a pattern of bright and dark bands much like the pressure patterns with a ringing organ pipe. It seems that light instead of traveling like it regularly does, it appears to be everywhere at once – in perfect synchronicity.

How does this not violate the laws of physics? The authors explain that light travels in two speeds – that is, the “phase velocity”, which describes how fast waves of a given wavelength move, and the “group velocity”, which describes how fast the light conveys energy or information. Only the group velocity must stay below the speed of light in a vacuum, Engheta says, and inside the waveguide, it does.

Applications for such a device could range from an antenna that emits light wave with sculpted phase front or used in nanoscale optical circuits, since the light leaking out of the waveguide is all in synch.

Results were published in the journal Physical Review Letters.

source: Science Mag

 

A high-resolution infrared image of the region surrounding the black hole at the center of our galaxy that shows the two orbits of the closest stars. Other orbits are shown in fainter orbits. (c) UCLA

Closest star orbiting our galaxy’s black hole discovered

Astronomers at UCLA university have made a remarkable discovery, after they’ve confirmed the presence of a star orbiting the black hole at the center of our galaxy in a mere 11-and-a-half years – that’s the shortest known orbit of any star near this black hole. The researchers involved in the paper describing the find claim that data will help test Einstein’s theory of relativity, which predicts space and time are warped around the gravitational field of a black hole.

A high-resolution infrared image of the region surrounding the black hole at the center of our galaxy that shows the two orbits of the closest stars. Other orbits are shown in fainter orbits. (c) UCLA

A high-resolution infrared image of the region surrounding the black hole at the center of our galaxy that shows the two orbits of the closest stars. Other orbits are shown in fainter orbits. (c) UCLA

The center of our galaxy is such a hectic place that direct and accurate optical observations around the black hole are simply impossible. Instead, scientists rely on the data they can gather by reading radio, X-ray and infrared waves. To their aid comes the Keck telescope on Mauna Kea in Hawaii, which has been watching stars near the galactic center in IR for 17 years, providing a detailed view of their dynamics. Using the telescope, astronomers answered some of the most puzzling astronomical questions in recent history, thus we now know:

  • at the center of our galaxy, lies a supermassive black hole some 26,000 light years ago, with a mass 4 million times that of our sun.
  • stars accelerate around the supermassive black hole. Further research should confirm the trend for the newly found, fastest orbiting star as well.
  • in 2005, the telescope took the first clear picture of the center of the Milky Way,  including the area surrounding the black hole, using laser guide star adaptive optics technology.

The newly confirmed star, dubbed SO-102, has had its orbit completely mapped, thanks to its short period. This is only the second star to have its orbit completely mapped, after the neighboring S0-2. Data from the two orbits together will help astronomers model the black hole itself, as direct IF observations are restricted due to it being invisible. Much of the merit for achieving these immense milestones in astronomy go to  Andrea Ghez, leader of the discovery team and a UCLA professor of physics and astronomy who holds the Lauren B. Leichtman and Arthur E. Levine Chair in Astrophysics. Ghez has  3,000 stars that orbit the black hole, and has been studying S0-2 since 1995.

“I’m extremely pleased to find two stars that orbit our galaxy’s supermassive black hole in much less than a human lifetime,” said Ghez.

“It is the tango of S0-102 and S0-2 that will reveal the true geometry of space and time near a black hole for the first time,” Ghez said. “This measurement cannot be done with one star alone.”

orbit animation

The first star with a sufficiently short orbital period to enable a complete three-dimensional reconstruction of its trajectory, SO-2, has an orbital period of around 16 years, but why did SO-102 take so long for it to be discovered? Well, the main reasons is that it’s very faint – around 16 times less brighter than SO-2. Thus, astronomers used the black hole data from prior observations to determine S0-102’s orbital properties, a feat made possible thanks to the Keck telescope’s novel adaptive optics technology, which allows for the 10-meter-diameter mirror to dynamically adjust in order to correct the distorting effects of the Earth’s atmosphere in real time.

“The Keck Observatory has been the leader in adaptive optics for more than a decade and has enabled us to achieve tremendous progress in correcting the distorting effects of the Earth’s atmosphere with high–angular resolution imaging,” Ghez said. “It’s really exciting to have access to the world’s largest and best telescope. It is why I came to UCLA and why I stay at UCLA.”

Milky Way’s dark core that warps time and space

Over time, Ghez and colleagues’ goals have evolved from demonstrating the existence of a black hole at the center of our galaxy, to validating fundamental laws of physics. At high velocities and gravity, Newtonian physics aren’t enough to explain irregularities in elliptical orbits, such as that of Mercury that has an irregular motion due to the sun’s mass to which it is in very close proximity. Measuring the warping effects of the Milky Way’s black hole on spacetime is a lot easier and evident than observations around the sun or similar stars, since the black hole is 4 million times more massive. Long term observations are required, however, in order to spot general relativistic effects, which are cumulative over multiple orbits.

One way for the scientists to test relativity is to measure the redshift, where the black hole’s gravitational influence stretches the wavelength of light towards the longer end of the electromagnetic spectrum.

“The fact that we can find stars that are so close to the black hole is phenomenal,” said Ghez, who also directs the UCLA Galactic Center Group. “Now it’s a whole new ballgame, in terms of the kinds of experiments we can do to understand how black holes grow over time, the role supermassive black holes play in the center of galaxies, and whether Einstein’s theory of general relativity is valid near a black hole, where this theory has never been tested before. It’s exciting to now have a means to open up this window.
“This should not be a neighborhood where stars feel particularly welcome,” she added. “But surprisingly, it seems that black holes are not as hostile to stars as was previously speculated.”

The findings were published in the journal Science.

source: UCLA newsroom

 

Astronomers find star orbiting a black hole in the center of our galaxy

Einstein’s theory, as well as other theories about the fundamental space-time fabric around a black hole may be strongly tested, after astronomers report the finding of a a star that orbits an enormous black hole at the center of the Milky Way galaxy.

Scientists explain it takes the star 11 and a half years to orbit the black hole, making it the object closest to any black hole that we know of. They hope they can use this data to figure out if Einstein was right in his prediction of how objects such as black holes can distort space and time. The faint star, called S0-102 has a stable and possibly changing orbit.

“The fact that we are finding stars this close to the supermassive black hole—a hundred times closer to its event horizon than ever identified before—shows just how fast this field is developing,” said study co-author Andrea Ghez, an astrophysicist at the University of California, Los Angeles. An event horizon is a boundary beyond which nothing, not evenlight, can escape from a black hole. “Our first goal has been to make the discoveries. But the next layer of science is the fundamental physics because this is an unparalleled laboratory for testing the general theory of relativity.”

If Einstein was correct in his theory, then the star’s orbit, although stable, will change slightly with every cycle, never returning to the same spot, creating a sort of daisy-like pattern. In order to figure this out, the most important thing is to study the star when it is closest to the black hole — the point known as the periapse.

“This is such an important discovery, because for stars located closer to the black hole, the gravitational field to study gets stronger and the effects more pronounced,” said Avi Loeb, a Harvard theoretical astrophysicist not involved with the new finding.

The findings were reported in the journal Science.

Faint galaxy sheds light on the dawn of the Universe – many more to be found

The first galaxies formed very fast after the Big Bang – in cosmic time, that is. It’s estimated that the earliest ones appeared some 500 million years after the Big Bang, a period about which researchers know very little.

How they observed it

Source: The CLASH team/Space Telescope Science Institute

Even though they are typically very bright, such galaxies are quite hard to observe because they are very far away and only a small fraction of their light can make its way towards Earth, a fraction so small it’s almost impossible to pick up. However, the Hubble telescope managed to detect light from a small galaxy emitted just 500 million years post-Big Bang, a period when the Universe was still in its infancy.

The telescope was able to do this thanks to a phenomena called gravitational lensing: basically, when you have an observe (Hubble), a distant source (the galaxy) and a certain distribution of matter (a galaxy cluster for example), the light emitted by the source can be bent and the observer can observe it easier; gravitational lensing is one of the predictions involved by Einstein‘s general theory of relativity. Basically, the massive gravity of the galaxy cluster acts just like a lens.

In this case, astronomer Wei Zheng and colleagues using the Hubble and Spitzer Space Telescopes reported light was magnified 15 times, making it just strong enough to be observed. Even so, the galaxy MACS 1149-JD appeared as a mere blob, and only after repeated measurements were they able to conclude that it is most likely a galaxy.

How they know its age

The Universe is expanding; galaxies produce light with specific spectral properties, based on the stars and gas they contain. Combine these two facts, and you can understand that light emitted by early galaxies was stretched shifting the entire spectrum into a different wavelength range, a phenomenon called cosmic redshift. All electromagnetic types of radiation (light included) have an electromagnetic spectrum – the range of all possible frequencies of electromagnetic radiation. Cosmic redshift means light seen coming from an object that is moving away is proportionally increased in wavelength, or shifted to the red end of the spectrum.

So, using multiple measurements from the Spitzer and Hubble telescope, they estimated that the light was emitted 490-505 million years after the Big Bang. But their conclusions are perhaps even more interesting. Instead of suggesting MACS 1149-JD is a special snowflake, astronomers believe there are many more such galaxies, formed in the same era, the ‘first’ era, just waiting to be discovered.

Scientific article was published in Nature

Faster than light Neutrinos FINALLY and OFFICIALLY debunked

This time last year, the whole scientific community was faced with one of the most controversial findings in recent history – namely, that neutrinos could travel at a speed greater than the speed of light, fact which would directly contravene with Einstein’s Theory of Special Relativity and, in consequence, force scientists to rethink the fundamental laws that govern the Universe. Last week, at the XXV International Conference on Neutrino Physics and Astrophysics, or Neutrino 2012 in short, the year’s major findings related to neutrinos was discussed. It was generally agreed by the attending scientists there that neutrinos are extraordinary particles, which exhibit still poorly understood characteristics, and at the same time, maybe more importantly, the scientists gathered there concluded and perfectly illustrated once and for all that neutrinos CAN NOT and WILL NOT ever travel faster than the speed of light.

The announcement which came from OPERA, the team of researchers from CERN which released the controversial claim following thorough experiments at  Italy’s Gran Sasso facility, was met with intense scrutiny even from the get go. A lot of theories were argued, each pointing to a different factor which may have pointed toward the 60 nanoseconds error. And an error it was, indeed, since later investigations confirmed that  the results were the product of an improperly seated optical cable in the OPERA experiment. The time delay introduced by this ill-placed cable was extremely small, but just enough to tamper with results.

Moreover, other scientific teams independentely recreated their own version of the OPERA experiment, most notably the MINOS team, which used protons from the Tevatron’s accelerator chain to produce neutrinos that were detected in a mine in Minnesota. Their results showed that the neutrino arrival time was consistent with the speed of light within experimental error; an experimental error which was about half the size of the original speed difference spotted by OPERA.

Long story short, the faster than light neutrino question has been officially and implacably debunked.

via Ars Technica

The ICARUS detector in Gran Sasso, Italy, also part of CERN, measured neutrinos and found they travel at sub-light speed.

Not that fast: neutrinos shown to travel at sub-light speed, refuting controversial claims

The ICARUS detector in Gran Sasso, Italy, also part of CERN, measured neutrinos and found they travel at sub-light speed.

The ICARUS detector in Gran Sasso, Italy, also part of CERN, measured neutrinos and found they travel at sub-light speed.

Last September the whole scientific community was set ablaze by a the controversial claim set forth by CERN scientists, part of the OPERA experiment, in which they announced that they had measured neutrinos traveling at a velocity faster than the speed of light – 60 nanoseconds faster to be more exact. The implications of this statement are monumental. One of the cornerstones of physics is that nothing can travel faster than the speed of light, an axiom postulated by Einstein, which had it been proven wrong would have forced scientists to re-think physics all together.

A new set of measurements carried out by a different group of CERN scientists, from the rival ICARUS experiment, did not reach the same conclusions, as their findings  “indicate the neutrinos do not exceed the speed of light,” as stated in the official CERN press release. The Universe’s speed limit is still in place.

Although the OPERA scientists cautiously announced their results last year, after measurements that lasted well over a year, their paper was one of the most scrutinized works in recent scientific history – they knew this from the very get go, and moreover urged for independent measurements that could confirm or refute their findings. Since then, scientists all over the world, conservative and eccentric alike, have been trying to find and propose various flaws in the OPERA experiment.

Located just a few metres from OPERA, the ICARUS experiment at the Gran Sasso Laboratory took a separate look at the flight of seven neutrinos that had also been recorded by the OPERA team. These were studied using a new measuring technique, called a liquid argon time projection chamber. The ICARUS scientists thus studied that beam of neutrinos packed into pulses just four nanoseconds long, instead of the ten microsecond long pulses used by the OPERA experiment. This allowed for a more accurate measurement of the timing. They eventually concluded that neutrinos traveled slightly below the speed of light.

“Our results are in agreement with what Einstein would like to have,” says Carlo Rubbia, the spokesperson for ICARUS and a Nobel-prize winning physicist at CERN.

The OPERA team itself announced sometime last month that they had uncovered possible timing problems with their original measurements, fact confirmed by ICARUS. “The OPERA case is now conclusively closed,” says Adam Falkowski, a theoretical physicist at the University of Paris-South in Orsay, France.

What’s important to note, though is that the CERN scientists at OPERA shouldn’t be blamed for their faulty paper, but actually praised for their hard work, perseverance and even courage for stepping up and assuming responsibility. Research Director Sergio Bertolucci stoutly defended the rights of scientists to make exceptional claims and to the rights of others to verify them.

“Whatever the result, the OPERA experiment has behaved with perfect scientific integrity in opening their measurement to broad scrutiny and inviting independent measurements. This is how science works,” said Bertolucci.

source – Nature

 

Computer simulation of superheated plasma swirling around the black hole at the center of our galaxy. (Image by Scott Noble/RIT)

Achieving the unbelievable: taking a picture of a black hole

Black Holes are the least understood entities, so far, in the Universe. However, if there’s one thing scientists know for sure about them, it’s that they’re the most extreme environment in cosmos. Black Holes have such a powerful, relentless gravity pull that it swallows absolutely everything in its vicinity, even light gets absorbed with zero reflection. This makes it practically invisible, which is why they’re very difficult to study. Scientists  are now set to embark on one of the most ambitious astrophysical ventures in history – taking a picture of a black hole. No, by no means is this a mad science stunt. The greatest minds of the scientific community have pledged their aid for the project and firmly believe this is possible, in an unprecedented worldwide combined effort, which only a few years ago would’ve been considered ludicrous.

“Nobody has ever taken a picture of a black hole,” said Dimitrios Psaltis, an associate professor of astrophysics at the University of Arizona’s Steward Observatory, who along with Daniel Marrone, an assistant professor of astronomy at Steward Observatory, organized a conference in Tucson, Ariz. where the endeavor was announced “We are going to do just that.”

“Even five years ago, such a proposal would not have seemed credible,” added Sheperd Doeleman, assistant director of the Haystack Observatory at Massachusetts Institute of Technology (MIT), who is the principal investigator of the Event Horizon Telescope, as the project is dubbed. “Now we have the technological means to take a stab at it.”

Computer simulation of superheated plasma swirling around the black hole at the center of our galaxy. (Image by Scott Noble/RIT)

Computer simulation of superheated plasma swirling around the black hole at the center of our galaxy. (Image by Scott Noble/RIT)

Einstein’s Theory of Relativity laid the foundation for the postulation of black holes, proving gravity does indeed influence light’s motion. Based on Einstein’s theory, fellow German physicist Karl Schwarzschild found a solution which described the gravitational field of a point mass and a spherical mass. Since then, scientists have observed, measured and conducted experiments for decades with significant breakthroughs, however it was never possible for them to directly observe or image a black hole. But if black holes don’t emit light, how is it possible to image them? Professor Doeleman explains this extremely ingenious project in a masterful way.

“As dust and gas swirls around the black hole before it is drawn inside, a kind of cosmic traffic jam ensues,” Doeleman explained. “Swirling around the black hole like water circling the drain in a bathtub, the matter compresses and the resulting friction turns it into plasma heated to a billion degrees or more, causing it to ‘glow’ – and radiate energy that we can detect here on Earth.”

Capturing the Milky Way’s supermassive black hole halo

Very clever, right? Once light passes the point of no return, or Event Horizon, it is lost forever, however its outline can be studied – this is called the black hole’s shadow.

Scientists have well founded reasons to believe that at the center of the Milky Way, like in most galaxies, if not all actually, lies a supermassive black hole (one to four million times the mass of the sun). Estimated at 26,000 light years away, to have a chance at seeing it scientists say you’d need a very big telescope – a telescope the size of the entire Earth to be more exact.

Of course, there’s a solution around this – connecting the biggest and most powerful radio telescopes in the world together. As such, 50 radio telescopes scattered around the globe have joined the effort, including the Submillimeter Telescope (SMT) on Mt. Graham in Arizona, telescopes on Mauna Kea in Hawaii and the Combined Array for Research in Millimeter-wave Astronomy (CARMA) in California. The astronomers hope once the biggest telescope in the world, the Atacama Large Millimeter Array (ALMA) in Chile, is finished it will provide the necessary power to provide the project, the Event Horizon Telescope as it was dubbed, with a great chance of success.

“In essence, we are making a virtual telescope with a mirror that is as big as the Earth,” Doeleman said. “Each radio telescope we use can be thought of as a small silvered portion of a large mirror. With enough such silvered spots, one can start to make an image.”

“The Event Horizon Telescope is not a first-light project, where we flip a switch and go from no data to a lot of data,” he added. “Every year, we increase its capabilities by adding more telescopes, gradually sharpening the image we see of the black hole.”

General Relativity predicts that the bright outline defining the black hole’s shadow must be a perfect circle. If this shape will be found to be deviated in any manner, than it would prove that the Theory of Relativity is wrong. On the contrary, if it is indeed a circle, little doubt would be left to cast.

Bringing together radio telescopes around the globe requires an extraordinary global team effort, and I can only salute this initiative. What a milestone for science would it be if the researchers will manage to capture a black hole’s shadow.

“This is not only the usual international conference where people come from all over the world because they are interested in sharing their research,” Psaltis said. “For the Event Horizon Telescope, we need the entire world to come together to build this instrument because it is as big as the planet. People are coming from all over the world because they have to work on it.”

source

CERN LHC

New CERN experiment finds neutrinos still faster than light

CERN LHC

The idea which states that nothing can travel faster than light is a corner stone of modern day physics, upon which scientists have built up models and theories of how the world, the Universe, works. If the statement is proven to be false, than our understanding of physics becomes undermined, and as such needs to be revised, with numerous implications. This is why the CERN experiment, which shockingly announced neutrinos could travel 60 nanoseconds faster than light, needs to be held under the utmost scrutiny. Now, another CERN announcement reports that another CERN experiment, conducted by a different team of researchers, and which used an improved version of the experimental set-up, came up with absolutely the same results.

Rightfully so, the scientific community was in awe when news of the neutrino announcement broke. Surely enough, numerous comments and theories followed that explained why the experiment was flawed, and susceptible to errors. In an experiment of this magnitude, absolutely nothing is negligible. Up until now, the number one culprit responsible for an eventual error in measurements concerned the shooting of long bunched neutrinos.

In the initial experiment, comprised of 16,000 separate measurements spread out over three years, launched long bunches of neutrinos, which lasted 10 millionths of a second. The experiment carried out by the Opera collaboration, short for Oscillation Project with Emulsion-tRacking Apparatus, addressed a different way through which the proton beams were produced, resulting in bunches just three billionths of a second long.

“A measurement so delicate and carrying a profound implication on physics requires an extraordinary level of scrutiny,” said Fernando Ferroni, president of Italian Institute for Nuclear Physics in a statement.

“The experiment Opera, thanks to a specially adapted Cern beam, has made an important test of consistency of its result. The positive outcome of the test makes us more confident in the result, although a final word can only be said by analogous measurements performed elsewhere in the world.”

As such, the bunch of neutrinos, created at the CERN facility, were yet again launched through the 730km circut to the giant detector at the Gran Sasso laboratory in Italy. Around 20 neutrino events have been measured at the Gran Sasso lab in the fine-tuned version of the experiment in the past few weeks, for each the scientists concluded from the new measurements that the neutrinos still appeared to be arriving earlier than they should.

“With the new type of beam produced by Cern’s accelerators we’ve been able to to measure with accuracy the time of flight of neutrinos one by one,” said Dario Autiero of the French National Centre for Scientific Research (CNRS). “The 20 neutrinos we recorded provide comparable accuracy to the 15,000 on which our original measurement was based. In addition their analysis is simpler and less dependent on the measurement of the time structure of the proton pulses and its relation to the neutrinos’ production mechanism.”

The CERN experiment is far from hitting the all clear zone, however. Further scrutiny by other independent parties are required, although there a just a few facilities in the rest of the world which have detectors capable of catching neutrinos – one is Fermilab, which is already at work replicating the CERN experiment. Data collection and further replication of the experiment will constantly be underway through the year at CERN. And of course, there are other error inflicting theories which have yet to be addressed.

The Opera measurements were reported in the the ArXiv preprint server on Friday morning and submitted for peer review in the Journal of High Energy Physics. Next year, teams working on two other experiments at Gran Sasso experiments – Borexino and Icarus – will begin independent cross-checks of Opera’s results. The US Minos experiment and Japan’s T2K experiment will also test the observations. Expect this to last for a while.

Particles faster than speed of light put to the test by Fermilab, US

Fermilab aerial view. (C) Fermilab

Fermilab aerial view. (C) Fermilab

Last week, ground shattering news hit the scientific community worldwide when CERN announced that their experiments showed that neutrinos fired from the CERN laboratory in Geneva, reached their destination of Gran Sasso, Italy, 60 billionths of a second faster than they would have if they had been traveling exactly at the speed of light. CERN scientists have since then made a call out to the scientific community worldwide to verify their data – one of US’s finest research labs, Fermilab, has taken upon itself to mimic the CERN experiment and prove or disproof the current data.

The implications of this, still far from confirmed, finding suggests that Einstein’s Theory of Relativity, which states that nothing can travel faster than the speed of light, reffered to as a “cosmic constant” by the physicist, is wrong. On its own hand, this would mean that any kind of grasp physicists have though they had upon the workings of the Universe, based on Einstein’s theory, needs to be flushed and rethought.

The OPERA experiment by the CERN research institute in Switzerland showed invisible neutrino particles traveled faster than light. The CERN researchers aren’t boosting their finding too blatantly, though, if anything they’re highly skeptical within their own ranks of the statement. Their invitation launched towards the worldwide scientific the community is a means of proving, as it is to disproving their finding.

“When an experiment finds an apparently unbelievable result and can find no artefact of the measurement to account for it, it’s normal procedure to invite broader scrutiny,” CERN Research Director Sergio Bertolucci said.

Now, scientists from Fermilab, a US Department of Energy laboratory in Chicago, said they will re-analyse the results.Interestingly enough, Fermilab conducted a similar experiment , called MINOS, back in 2007, but its results allowed for a margin of error that made it unclear if neutrinos were indeed travelling faster than light. CERN experiment calculated a margin of error of ten nanoseconds, which means that the sixty nanoseconds by which the neutrinos outran light were still significant. This time around, Fermilab wants to re-establish the experiment in a such a precise manner that an error no greater of nanosecond will occur.

“We’re updating the [MINOS] to measure more precisely the time that it takes the neutrinos to travel from Fermilab to the detector in Minnesota,” spokesman Kurt Riesselmann said.

“The experiment will also take new data in the upcoming year and analyse those, and hope to improve the position to confirm or refute the OPERA result,” Dr Riesselmann said.

The folllowing months will be extremely anxious for everybody involved, as the US scientists will be at the center of the stage. The HLC has offered some amazing break thorough in the long road towards understading the Universe, and this very find, if found to be true, will without a doubt make it one of the new millenia’s greatest milestones. One can only wonder what we could’ve knew by now if the US government had approved the development of the SuperConducting SuperCollider less than a generation ago, in 1993. It would have been four times as powerful as the Large Hadron Collider currently being used by CERN scientists in Geneva.