Tag Archives: jillian scharr

August 28, 2013 · 12:25 pm

Wormhole best time-travel option

Wormhole best time-travel option, astrophysicist says

By Jillian Scharr

Published August 27, 2013

LiveScience
  • Back to the Future

    In the movie “Back to the Future,” Doc Brown builds a time machine into a Delorean. (Universal)

The concept of a time machine typically conjures up images of an implausible plot device used in a few too many science-fiction storylines. But according to Albert Einstein’s general theory of relativity, which explains how gravity operates in the universe, real-life time travel isn’t just a vague fantasy.

Traveling forward in time is an uncontroversial possibility, according to Einstein’s theory. In fact, physicists have been able to send tiny particles called muons, which are similar to electrons, forward in time by manipulating the gravity around them. That’s not to say the technology for sending humans 100 years into the future will be available anytime soon, though.

Time travel to the past, however, is even less understood. Still, astrophysicist Eric W. Davis, of the EarthTech International Institute for Advanced Studies at Austin, argues that it’s possible. All you need, he says, is a wormhole, which is a theoretical passageway through space-time that is predicted by relativity. [Wacky Physics: The Coolest Little Particles in Nature]

“You can go into the future or into the past using traversable wormholes,” Davis told LiveScience.

Where’s my wormhole?
Wormholes have never been proven to exist, and if they are ever found, they are likely to be so tiny that a person couldn’t fit inside, never mind a spaceship.

‘There are numerous space-time geometry solutions that exhibit time travel.’

– Astrophysicist Eric W. Davis 

Even so, Davis’ paper, published in July in the American Institute of Aeronautics and Astronautics’ journal, addresses time machines and the possibility that a wormhole could become, or be used as, a means for traveling backward in time.

Both general-relativity theory and quantum theory appear to offer several possibilities for traveling along what physicists call a “closed, timelike curve,” or a path that cuts through time and space essentially, a time machine.

In fact, Davis said, scientists’ current understanding of the laws of physics “are infested with time machines whereby there are numerous space-time geometry solutions that exhibit time travel and/or have the properties of time machines.”

A wormhole would allow a ship, for instance, to travel from one point to another faster than the speed of light sort of. That’s because the ship would arrive at its destination sooner than a beam of light would, by taking a shortcut through space-time via the wormhole. That way, the vehicle doesn’t actually break the rule of the so-called universal speed limit the speed of light because the ship never actually travels at a speed faster than light. [Warped Physics: 10 Effects of Traveling Faster Than Light]

Theoretically, a wormhole could be used to cut not just through space, but through time as well.

“Time machines are unavoidable in our physical dimensional space-time,” David wrote in his paper. “Traversable wormholes imply time machines, and [the prediction of wormholes] spawned a number of follow-on research efforts on time machines.”

However, Davis added, turning a wormhole into a time machine won’t be easy. “It would take a Herculean effort to turn a wormhole into a time machine. It’s going to be tough enough to pull off a wormhole,” he told LiveScience.

That’s because once a wormhole is created, one or both ends of it would need to be accelerated through time to the desired position, according to general relativity theory.

Challenges ahead
There are several theories for how the laws of physics might work to prevent time travel through wormholes.

“Not only do we assume [time travel into the past] will not be possible in our lifetime, but we assume that the laws of physics, when fully understood, will rule it out entirely,” said Robert Owen, an astrophysicist at Oberlin College in Ohio who specializes in black holes and gravitation theory.

According to scientists’ current understanding, keeping a wormhole stable enough to traverse requires large amounts of exotic matter, a substance that is still very poorly understood.

General relativity can’t account for exotic matter according to general relativity, exotic matter can’t exist. But exotic matter does exist. That’s where quantum theory comes in. Like general relativity, quantum theory is a system for explaining the universe, kind of like a lens through which scientists observe the universe. [Video How to Time Travel]

However, exotic matter has only been observed in very small amounts not nearly enough to hold open a wormhole. Physicists would have to find a way to generate and harness large amounts of exotic matter if they hope to achieve this quasi-faster-than-light travel and, by extension, time travel.

Furthermore, other physicists have used quantum mechanics to posit that trying to travel through a wormhole would create something called a quantum back reaction.

In a quantum back reaction, the act of turning a wormhole into a time machine would cause a massive buildup of energy, ultimately destroying the wormhole just before it could be used as a time machine.

However, the mathematical model used to calculate quantum back reaction only takes into account one dimension of space-time.

“I am confident that, since [general relativity] theory has not failed yet, that its predictions for time machines, warp drives and wormholes remain valid and testable, regardless of what quantum theory has to say about those subjects,” Davis added.

This illustrates one of the key problems in theories of time travel: physicists have to ground their arguments in either general relativity or quantum theory, both of which are incomplete and unable to encompass the entirety of our complex, mysterious universe.

Before they can figure out time travel, physicists need to find a way to reconcile general relativity and quantum theory into a quantum theory of gravity. That theory will then serve as the basis for further study of time travel.

Therefore, Owen argues that it’s impossible to be certain of whether time travel is possible yet. “The wormhole-based time-machine idea takes into account general relativity, but it leaves out quantum mechanics,” Owen added. “But including quantum mechanics in the calculations seems to show us that the time machine couldn’t actually work the way we hope.”

Davis, however, believes scientists have discovered all they can about time machines from theory alone, and calls on physicists to focus first on faster-than-light travel.

“Until someone makes a wormhole or a warp drive, there’s no use getting hyped up about a time machine,” Davis told LiveScience.

Accomplishing this will require a universally accepted quantum gravity theory an immense challenge so don’t go booking those time-travel plans just yet.

Read more: http://www.foxnews.com/science/2013/08/27/wormhole-best-bet-for-time-machine/?intcmp=obinsite#ixzz2dIFw73ID

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May 14, 2013 · 6:04 pm

Faster than light drives a reality?

Warp speed, Scotty: Faster than light drives a reality?

By Jillian Scharr

Published May 14, 2013

TechNewsDaily

  • The 100 Year Spaceship

    NASA appears to be debating a way to permanently colonize another planet, boldly going where no one has ever gone — and where no one could come back, some fear. (Paramount)

In the “Star Trek” TV shows and films, the U.S.S. Enterprise’s warp engine allows the ship to move faster than light, an ability that is, as Spock would say, “highly illogical.”

However, there’s a loophole in Einstein’s general theory of relativity that could allow a ship to traverse vast distances in less time than it would take light. The trick? It’s not the starship that’s moving — it’s the space around it.

In fact, scientists at NASA are right now working on the first practical field test toward proving the possibility of warp drives and faster-than-light travel. Maybe the warp drive on “Star Trek” is possible after all. [See also: Warp Drive: Can It Be Done? (Video)]

‘Nature can do it. So the salient question is, can we?’

– Physicist Harold ‘Sonny’ White, with NASA’s Johnson Space Center 

According to Einstein’s theory, an object with mass cannot go as fast or faster than the speed of light. The original “Star Trek” series ignored this “universal speed limit” in favor of a ship that could zip around the galaxy in a matter of days instead of decades. They tried to explain the ship’s faster-than-light capabilities by powering the warp engine with a “matter-antimatter” engine. Antimatter was a popular field of study in the 1960s, when creator Gene Roddenberry was first writing the series. When matter and antimatter collide, their mass is converted to kinetic energy in keeping with Einstein’s mass-energy equivalence formula, E=mc2.

In other words, matter-antimatter collision is a potentially powerful source of energy and fuel, but even that wouldn’t be enough to propel a starship to faster-than-light speeds.

Nevertheless, it’s thanks to “Star Trek” that the word “warp” is now practically synonymous with faster-than-light travel.

Is warp drive possible?
Decades after the original “Star Trek” show had gone off the air, pioneering physicist and avowed Trek fan Miguel Alcubierre argued that maybe a warp drive is possible after all. It just wouldn’t work quite the way “Star Trek” thought it did.

Things with mass can’t move faster than the speed of light. But what if, instead of the ship moving through space, the space was moving around the ship?

Space doesn’t have mass. And we know that it’s flexible: space has been expanding at a measurable rate ever since the Big Bang. We know this from observing the light of distant stars — over time, the wavelength of the stars’ light as it reaches Earth is lengthened in a process called “redshifting.” According to the Doppler effect, this means that the source of the wavelength is moving further away from the observer — i.e. Earth.

So we know from observing redshifted light that the fabric of space is movable. [See also: What to Wear on a 100-Year Starship Voyage]

Alcubierre used this knowledge to exploit a loophole in the “universal speed limit.” In his theory, the ship never goes faster than the speed of light — instead, space in front of the ship is contracted while space behind it is expanded, allowing the ship to travel distances in less time than light would take. The ship itself remains in what Alcubierre termed a “warp bubble” and, within that bubble, never goes faster than the speed of light.

Since Alcubierre published his paper “The Warp Drive: Hyper-fast travel within general relativity” in 1994, many physicists and science fiction writers have played with his theory —including “Star Trek” itself. [See also: Top 10 Star Trek Technologies]

Alcubierre’s warp drive theory was retroactively incorporated into the “Star Trek” mythos by the 1990s TV series “Star Trek: The Next Generation.”

In a way, then, “Star Trek” created its own little grandfather paradox: Though ultimately its theory of faster-than-light travel was heavily flawed, the series established a vocabulary of light-speed travel that Alcubierre eventually formalized in his own warp drive theories.

The Alcubierre warp drive is still theoretical for now. “The truth is that the best ideas sound crazy at first. And then there comes a time when we can’t imagine a world without them.” That’s a statement from the 100 Year Starship organization, a think tank devoted to making Earth what “Star Trek” would call a “warp-capable civilization” within a century.

The first step toward a functional warp drive is to prove that a “warp bubble” is even possible, and that it can be artificially created.

That’s exactly what physicist Harold “Sonny” White and a team of researchers at NASA’s Johnson Space Center in Texas are doing right now.

NASA’s warp drive project
According to Alcubierre’s theory, one could create a warp bubble by applying negative energy, or energy created in a vacuum. This process relies on the Casimir effect, which states that a vacuum is not actually a void; instead, a vacuum is actually full of fluctuating electromagnetic waves. Distorting these waves creates negative energy, which possibly distorts space-time, creating a warp bubble.

To see if space-time distortion has occurred in a lab experiment, the researchers shine two highly targeted lasers: one through the site of the vacuum and one through regular space. The researchers will then compare the two beams, and if the wavelength of the one going through the vacuum is lengthened, i.e. redshifted, in any way, they’ll know that it passed through a warp bubble. [See also: How Video Games Help Fuel Space Exploration]

White and his team have been at work for a few months now, but they have yet to get a satisfactory reading. The problem is that the field of negative energy is so small, the laser so precise, that even the smallest seismic motion of the earth can throw off the results.

When we talked to White, he was in the process of moving the test equipment to a building on the Johnson Space Center campus that was originally built for the Apollo space program. “The lab is seismically isolated, so the whole floor can be floated,” White told TechNewsDaily. “But the system hadn’t been [activated] for a while so part of the process was, we had the system inspected and tested.”

White is now working on recalibrating the laser for the new location. He wouldn’t speculate on when his team could expect conclusive data, nor how long until fully actuated warp travel might be possible, but he remains convinced that it’s only a matter of time.

“The bottom line is, nature can do it,” said White. “So the salient question is, ‘can we?'”

Read more: http://www.foxnews.com/tech/2013/05/14/warp-speed-scotty-star-trek-ftl-drive-may-actually-work/?intcmp=features#ixzz2TJpE9oFk

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May 4, 2013 · 5:02 pm

Fly-sized robot takes first flight

Fly-sized robot takes first flight

By Jillian Scharr

Published May 03, 2013

TechNewsDaily

  • RoboticInsect

    The RoboBee is the smallest flight-capable robot to date. (Kevin Ma and Pakpong Chirarattananon, Harvard University.)

Flies have tiny wings and even tinier brains, yet they are capable of flying swiftly and agilely through even turbulent air. How do they do it?

And could we create a robot capable of doing the same?

That’s the question that’s been buzzing around Harvard professor Robert Wood’s head for 12 years now. And finally, after years of testing and the invention of an all-new manufacturing technique inspired by children’s pop-up books, Wood and his team at the Wyss Institute for Biologically Inspired Engineering at Harvard University have created a robot the size of a penny that is capable of remote-controlled flight. 

‘Large robots can run on electromagnetic motors, but at this small scale, you have to come up with an alternative.’

– Kevin Ma, a graduate student at Harvard’s School of Engineering and Applied Sciences 

You’d think that the smaller something is, the easier it’d be to make. But there’s a point at which making things smaller becomes harder rather than easier, which is why making a functional fly-sized robot has proved such a challenge.

The so-called RoboBee flaps its wings approximately 120 times per second, almost faster than the eye can track, and is capable of hovering and flying horizontally in multiple directions like a helicopter.

At 80 milligrams, which is less than one-twentieth the weight of a dime, the robot is so small that traditional components of flight-capable machines simply wouldn’t work, so the team had to create new ones.

“Large robots can run on electromagnetic motors, but at this small scale, you have to come up with an alternative, and there wasn’t one,” Kevin Ma, a co-lead author and graduate student at Harvard’s School of Engineering and Applied Sciences, said in a statement.

In place of electromagnetic motors, the team used ceramic strips that can expand or contract when hit with an electric field, a technique known as piezoelectricity. 

The problem of building these parts at a fly-sized scale was also an enormous obstacle. For example, the robot has no onboard power source — instead, it receives electricity via a thin wire connected to an external battery.

To build the other parts, the team looked for inspiration not from the natural world, but from children’s pop-up books and origami.

Their solution is a groundbreaking technique that involves layering and folding sheets of carbon fiber, brass, ceramic and other materials, and then using extremely precise lasers to cut these sheets into structures and circuits. After that, the sheets can be assembled into extremely small but entirely functional devices in a single movement, just like a children’s pop-up book.    

Wood and his team devised the pop-up technique in 2011, publishing a paper on it in February 2012. And last summer, after years of failed prototypes, the first RoboBee took flight in a Harvard robotics lab at 3 a.m.

Read more: http://www.foxnews.com/tech/2013/05/03/fly-sized-robot-takes-first-flight/?intcmp=trending#ixzz2SN5zkDo9

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