Warp Drive More Possible Than Thought, Scientists Say

A ring-shaped warp drive device could transport a football-shape starship (center) to effective speeds faster than light. 

The concept was first proposed by Mexican physicist Miguel Alcubierre.

CREDIT: Harold White

A warp drive to achieve faster-than-light travel — a concept popularized in television's Star Trek — may not be as unrealistic as once thought, scientists say.

A warp drive would manipulate space-time itself to move a starship, taking advantage of a loophole in the laws of physics that prevent anything from moving faster than light.

A concept for a real-life warp drive was suggested in 1994 by Mexican physicist Miguel Alcubierre; however, subsequent calculations found that such a device would require prohibitive amounts of energy.

Now physicists say that adjustments can be made to the proposed warp drive that would enable it to run on significantly less energy, potentially bringing the idea back from the realm of science fiction into science.

"There is hope," Harold "Sonny" White of NASA's Johnson Space Center said here Friday (Sept. 14) at the 100 Year Starship Symposium, a meeting to discuss the challenges of interstellar spaceflight.

The Trouble With Neutrinos That Outpaced Einstein’s Theory

The British astrophysicist Arthur S. Eddington once wrote, “No experiment should be believed until it has been confirmed by theory.”

So when a group of physicists going by the acronym Opera announced in September that a batch of the strange subatomic particles known as neutrinos had traveled faster than the speed of light in a 457-mile trip through the earth, the first response among many physicists was to wonder what had gone wrong with the experiment. 

After all, Albert Einstein’s theory of relativity, which proclaimed the speed of light as the cosmic speed limit, is the foundation of modern science and has been shown to work to exquisite precision zillions of times. 

Knock it down and you potentially open the door to all kinds of things, like the ability to go back in time and kill your grandfather.

That, of course, did not stop the rest of us in the physics bleachers from dragging the old guru of space-time by his frizzy coronal hair into the media version of the public square and crowing that, perhaps this time at last, Einstein was finally going to be proved wrong. 

Neutrino jokes proliferated on the Internet, as well as this rousing song by the Corrigan Brothers and Pete Creighton: 

Tooraloo, tooraloo, tooraloo, tooralino,

Is light now slower than a neutrino?

Now it seems that Einstein’s six-month nightmare may be over.

Last week another team of physicists whose apparatus lives right next door to the Opera group — under Gran Sasso mountain in Italy — reported that they had clocked neutrinos, produced in an accelerator at CERN, outside Geneva, racing over the same path to Gran Sasso at the speed of light and not a whit faster. 

Which is exactly how fast scientists had always thought the enigmatic particles, with barely zilch for mass, should go.

The second group, which goes by the acronym Icarus, was led by Carlo Rubbia, a former director of CERN and a Nobel-winning physicist, who called the results “very convincing.”

Physicists swung into line with great sighs of relief.

“The evidence is beginning to point toward the Opera result being an artifact of the measurement,” said CERN’s research director, Sergio Bertolucci.

Cue the famous picture of Einstein sticking out his tongue. As it happened, the Icarus result was announced on March 16, two days after his 133rd birthday — almost in time for the cake.

Adding to the sense of finality was the simple fact — as Eddington might have pointed out — that faster-than-light neutrinos had never been confirmed by theory. Or as John G. Learned, a neutrino physicist at the University of Hawaii, put it in an e-mail, “An interesting result of all this fracas is that no new model I have seen (or heard of from my friends) really is credible to explain the faster-than-light neutrinos.”

During a panel discussion recently at the American Museum of Natural History, Sheldon L. Glashow, a physics professor and Nobel laureate from Boston University, said the best theory he had heard was that the neutrinos had behaved lawfully in Switzerland and speeded up when they crossed the border into Italy.

Eddington’s dictum is not as radical as it might sound. He made it after early measurements of the rate of expansion of the universe made it appear that our planet was older than the cosmos in which it resides — an untenable notion.

“It means that science is not just a book of facts, it is understanding as well,” explained Michael S. Turner, a cosmologist at the University of Chicago, who says the Eddington saying is one of his favourites. 

If a “fact” cannot be understood, fitted into a conceptual framework that we have reason to believe in, or confirmed independently some other way, it risks becoming what journalists like to call a “permanent exclusive” wrong. 

Read more of this article: The Trouble With Neutrinos - NYTimes.com

Star Trek Warp Drives: Slowing Down is a Planet Killer

Fans of science fiction will have one less technology to look forward to in the future.

The ubiquitous warp drive made popular in such shows as Star Trek, could fry any planetary system it stops in.

Faster than light technology (FLT) has been a dream for many sc-fi fans and even scientists who want an easy way to travel the vast distances in space.

Warp drives also solves the problem of relativity where the brave interstellar travelers can explore galaxies without their families back on Earth ageing a hundred years.

While Star Trek's warp drive is still purely a product of Hollywood imagination there are some concepts in physics that explore FTL.

One of those concepts is the Alcubierre warp drive proposed by Mexican theoretical physicist Miguel Alcubierre in 1994.

Basically the Alcubierre warp drive proposes that a ship would be propelled to faster than light speeds by creating a bubble of negative energy around it. Spacetime is compressed in front of the bubble and expanded behind it.

The ship would ride the bubble cruising at faster than light speeds while inside the bubble no faster than light prohibition is broken.

As enticing as the Alcubierre warp drive is or any other means for travelling faster than light, there is still the problem of stopping and stopping an FTL ship is going to wreak havoc on anyone unlucky enough to be in the ship's way.

According to Brendan McMonigal, Prof Geraint Lewis and Prof Philip O'Byrne of the University of Sydney, Alcubierre didn't take into consideration that many types of cosmic particles that the warp drive spaceship would encounter on its travels.

The research team found that these particles can get swept up in the warp bubble and after the ship decelerates from superluminal speed, the particles can get released in energetic outbursts strong enough to destroy anyone at the destination in front of the ship.

"Any people at the destination," the team's paper concludes, "would be gamma ray and high energy particle blasted into oblivion due to the extreme blueshifts for forward region particles."

One piece of good news that the team did find out is that while the warp drive is beyond human technology at the moment the theory behind the Alcubierre drive makes this possible in the future.

"Einstein's General Relativity tells us that gravity is the result of warped spacetime," McMonigal told the Register. "This means that simply by being in the gravitational field of the Earth as we are now, we are experiencing warped spacetime.

"What the warp drive equations tell us is what distribution of "stuff" we would need to create the spacetime deformation which would result in a ship travelling to a distant location in a short amount of time. In fact, the question of how we would generate this distribution is the main barrier to this technology."

In other words the drive is possible but researchers will have to figure how to stop the destination of the ship from disintegrating upon arrival.

Markarian Chain: A stretch of galaxies in the Virgo cluster

Credit: Larry Van VleetThis stunning image by skywatcher Larry Van Vleet is of Markarian's Chain, a stretch of galaxies in the Virgo cluster.

The galaxies are said to be in a smooth, curved line making them appear to be connected in a chain.

Located about 70 million light-years away, the Virgo cluster is a large collection of some 2,000 galaxies that dominate our part of the universe.

A light-year is the distance light travels in one year, or about 6 trillion miles (10 trillion kilometers).

ESA ESO VLT: Ancient Galaxies Snapped

Light traveling for 10 billion years now gives astronomers a glimpse into the largest galaxies in the Universe.

Found in the Fornax constellation, these galaxies (highlighted in red) burst on the cosmic scene with very rapid, intense star formation.

OPERA: Neutrinos may be tachyons

For a few days in September 2011, it was the biggest story in the world. The little-known OPERA experiment in Gran Sasso, Italy, had just made an electrifying claim - that subatomic particles called neutrinos had travelled faster than the speed of light.

Next year, two experiments - MINOS at Fermilab in Batavia, Illinois, and T2K in Japan (pictured) - will be able to test the claim. If it stands up, how should we meld these misbehaving particles with the rest of physics?
One option is via tachyons, hypothetical particles that are born speeding faster than light. It turns out that the speed limit imposed by Einstein's special theory of relativity isn't so much a cap that nothing can exceed as a barrier that nothing can cross.

Tachyons were dreamed up to illustrate this: particles born faster than light pose no problem for special relativity as long as they spend their whole lives in the fast lane.

Are neutrinos tachyons? One way they might be is if the universe is filled with a field that interacts with particles as they fly through it. If photons have more drag in that field than neutrinos do, then neutrinos would naturally outpace the speed of light.

This idea may feel familiar: light travels slower in glass than in a vacuum, for instance. So the universe might be permeated with a sort of diffuse glass.

If neutrinos do turn out to be tachyons, theorists will still have their work cut out. Though they are born speeding, tachyons interfere with another demand of special relativity: that a particle's behaviour be the same no matter where it is facing or how fast it is going.

Meanwhile, there is no shortage of other theories scrabbling to explain this most astonishing of results.

A Star is Born: Dark-Hued Nebula

The region lies near the southern end of Taurus located on the border of the constellations of Taurus and Perseus more than 400 light-years away. 

A light-year is the distance light travels in one year, or about 6 trillion miles (10 trillion kilometers).

CREDIT: Adam Block/Mount Lemmon SkyCenter/University of Arizona

This photo shows the cosmic region known as Sh2-239 and LDN 155, where star formation activity has caused the mix of dust and colors in the nebulas visible here.

The deep colours and dark clouds in this image resemble paintings by some of history's greatest artists.

Astrophotographer Adam Block of the Mt. Lemmon SkyCenter at the University of Arizona was one of the first to capture the nebula in such detail.

He took multiple exposures to collect enough light for an image that would otherwise not be evident to the eye.

"Sh2-239 is my favourite object, because although it is a well-studied nebula, not even professional astronomers have seen it in such detail and in the visible light." Block wrote in an email.

The region lies near the southern end of the constellation Taurus, near the border of the constellation Perseus, more than 400 light-years away.

A light-year is the distance light travels in one year, or about 6 trillion miles (10 trillion kilometers).

The region is often photographed by skywatchers and consists of bright red emission nebulas, star clusters, complex dark nebulas and blue reflected light. The spot is known as a birthplace for stars.

A star develops from a giant, slowly rotating cloud that is made up almost entirely of hydrogen and helium. The process creates new stars and releases cosmic dust and gas.

CERN Press Release on Neutrino Experiment

Geneva, 23 September 2011. The OPERA experiment, which observes a neutrino beam from CERN 730 km away at Italy’s INFN Gran Sasso Laboratory, will present new results in a seminar at CERN this afternoon at 16:00 CEST.

The seminar will be webcast at http://webcast.cern.ch. Journalists wishing to ask questions may do so via twitter using the hash tag #nuquestions, or via the usual CERN press office channels.

The OPERA result is based on the observation of over 15000 neutrino events measured at Gran Sasso, and appears to indicate that the neutrinos travel at a velocity 20 parts per million above the speed of light, nature’s cosmic speed limit.

Given the potential far-reaching consequences of such a result, independent measurements are needed before the effect can either be refuted or firmly established. This is why the OPERA collaboration has decided to open the result to broader scrutiny. The collaboration’s result is available on the preprint server arxiv.org: http://arxiv.org/abs/1109.4897.

The OPERA measurement is at odds with well-established laws of nature, though science frequently progresses by overthrowing the established paradigms. For this reason, many searches have been made for deviations from Einstein’s theory of relativity, so far not finding any such evidence.

The strong constraints arising from these observations makes an interpretation of the OPERA measurement in terms of modification of Einstein’s theory unlikely, and give further strong reason to seek new independent measurements.

“This result comes as a complete surprise,” said OPERA spokesperson, Antonio Ereditato of the University of Bern. “After many months of studies and cross checks we have not found any instrumental effect that could explain the result of the measurement.  

While OPERA researchers will continue their studies, we are also looking forward to independent measurements to fully assess the nature of this observation.”

“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, and this is exactly what the OPERA collaboration is doing, it’s good scientific practice,” said CERN Research Director Sergio Bertolucci.
 
“If this measurement is confirmed, it might change our view of physics, but we need to be sure that there are no other, more mundane, explanations. That will require independent measurements.”

In order to perform this study, the OPERA Collaboration teamed up with experts in metrology from CERN and other institutions to perform a series of high precision measurements of the distance between the source and the detector, and of the neutrinos’ time of flight.

The distance between the origin of the neutrino beam and OPERA was measured with an uncertainty of 20 cm over the 730 km travel path. The neutrinos’ time of flight was determined with an accuracy of less than 10 nanoseconds by using sophisticated instruments including advanced GPS systems and atomic clocks.

The time response of all elements of the CNGS beam line and of the OPERA detector has also been measured with great precision.

"We have established synchronization between CERN and Gran Sasso that gives us nanosecond accuracy, and we’ve measured the distance between the two sites to 20 centimetres,” said Dario Autiero, the CNRS researcher who will give this afternoon’s seminar. 

“Although our measurements have low systematic uncertainty and high statistical accuracy, and we place great confidence in our results, we’re looking forward to comparing them with those from other experiments."

“The potential impact on science is too large to draw immediate conclusions or attempt physics interpretations. My first reaction is that the neutrino is still surprising us with its mysteries.” said Ereditato. “Today’s seminar is intended to invite scrutiny from the broader particle physics community.”

The OPERA experiment was inaugurated in 2006, with the main goal of studying the rare transformation (oscillation) of muon neutrinos into tau neutrinos. One first such event was observed in 2010, proving the unique ability of the experiment in the detection of the elusive signal of tau neutrinos.


CERN Press Release

CERN: Speed of light broken

Prof Jenny Thomas, of University College London, says the claims, if proven true, would call into question our very understanding of physics and the universe.

She said: "It would turn everything on its head. It is too awful to think about.

"The basic thing it that would be questioned is that there is an absolute speed limit which is the basis of special relativity and that is a huge building block of modern physics.

"It permeates everything to do with how we have modelled the universe and everything. It would be very hard to predict what the effects would be."

UPDATE: The ‘discovery’ was made by the OPERA experiment while the neutrinos were beamed from Geneva to a lab in Gran Sasso in Italy. The pre-print of the report, prepared by CERN and published today (23rd September) can be found here: http://arxiv.org/abs/1109.4897

Special relativity is integral to the understanding of particle accelerators and the creation of particle beams, which are of crucial importance in fields like medicine and engineering, she said.

It could even be that the most famous equation of all time, E=mc2, turns out to be incorrect because it is based on the law of special relativity, Prof Thomas said.

Before any conclusions can be drawn, the CERN team's results will be checked by scientists across the globe including at Fermilab near Chicago, where a similar experiment known as Minos is based.

Prof Thomas – the co-spokesperson for the Minos project – said the team had thrown up similar results several years ago but had discounted them because the possible margin of error was too high.

She said: "Our errors were rather large so we dismissed it. Nothing is further from your belief than that the results might be correct.

CERN Press Release by CMS: http://www.interactions.org/cms/?pid=1031063

"When I heard about the Cern results my first thought was that they must be wrong, there must be something they have not taken into account."

Potential errors could occur in the measurement of distance between the point the particle was created and where it was detected; the time it took to travel from one point to the other; or in the structure of the accelerator which the whole measurement relies upon.

Prof Thomas added: "I think everyone is sceptical. The scientists themselves have admitted they are sceptical but they cannot see what they have done wrong.

"We will repeat our experiment with higher precision, hopefully in the next six months."

The Fermilab team will then begin a second stage of their experiment, called Minos Plus, which is even more similar to the Cern trial and will deliver results accurate to one nanosecond, she said.

Engaging Maximum Thrust to Explore the Univers

The Apollo 10 moon probe is currently listed as the fastest manned vehicle in history, having reached a maximum speed of 39,895 kilometres per hour. At this speed, it would take 120,000 years to cover the 4 light years to Alpha Centauri, the nearest star system.

So if we want to explore the depths of deep space and journey to Alpha Centauri and beyond, we're going to need some new technologies. Here, we look at 10 of the most intriguing.

The technologies range widely in their plausibility. Some, we could more or less build tomorrow if we wanted to, while others may well be fundamentally impossible.

Ion thruster
Conventional rockets work by shooting gases out of their rear exhausts at high speeds, thus generating thrust. Ion thrusters use the same principle, but instead of blasting out hot gases, they shoot out a beam of electrically charged particles, or ions.

They provide quite a weak thrust, but crucially they use far less fuel than a rocket to get the same amount of thrust. Providing they can be made to keep working steadily for a long time, they could eventually accelerate a craft to high speeds.

They have already been used on several spacecraft, such as Japan's Hayabusa probe and Europe's SMART-1 lunar mission, and the technology has been improving steadily.

A particularly promising variant is the variable specific impulse magnetoplasma rocket (VASIMR). This works on a slightly different principle to other ion thrusters, which accelerate the ions using a strong electric field. Instead, VASIMR uses a radio-frequency generator, rather like the transmitters used to broadcast radio shows, to heat ions to 1 million °C.

It does this by taking advantage of the fact that in a strong magnetic field, like those produced by the superconducting magnets in the engine, ions spin at a fixed frequency. The radio-frequency generator is then tuned to that frequency, injecting extra energy into the ions and massively increasing the thrust.

Initial tests have been promising, and if all goes well, VASIMR could be used to take humans to Mars in 39 days