Warp Factor

April 23, 2009

Excitement is mounting over the imminent release of J.J. Abrams' Star Trek "prequel" wherein a promising young actor named Chris Pine attempts to walk in William Shatner's legendary footsteps as the young James T. Kirk. Even if you're not a hard-core Trekkie, it's tough to deny the enormous impact the series (both film and TV) has had on popular culture. "Beam me up Scotty." "He's dead, Jim." "Set phasers to stun." Not to mention the almost certain expendability of any unfortunate crew member wearing a bright red shirt (brilliantly satirized by the character of Guy in the spoof film Galaxy Quest).

And don't forget all that cutting-edge futuristic technology: phasers, the Holodeck, the transporter room, and those nifty handheld devices that inspired a thousand cell phone designs. But perhaps the most famous is the Enterprise's "warp drive", which enables it to travel faster than the speed of light -- something normally in violation of the laws of relativity, which say that nothing with mass can travel faster than light, even the tiniest subatomic particle. 

But is a warp drive possible for real? Alas, Wikipedia tells me that

At present, there is no known way to naturally or artificially establish a separate, finite space-time region or "bubble" - such a region is necessary to locally suspend or encapsulate the spacecraft within its view of a "normal" space-time. Concurrently, external from that region, there would exist a "warped" space-time, through which the separate region travels at velocities exceeding c, the speed of light.

Unless, of course, one happens to have a plentiful supply of antimatter and a "gravimetric field displacement manifold" handy, a.k.a., a warp core. The warp core is the literal heart of the Enterprise, a special kind of reactor in which matter and antimatter annihilate and release energy with 100% efficiency, thereby beating the laws of thermodynamics as well as relativity. When Stephen Hawking guest-starred on an episode of Star Trek: The Next Generation, he was given a tour of the set. Stopping in front of the model of the warp core, he commented, "I'm working on that." (Hawking has been gravely ill this past week, but it's looking like he'll pull through, and we wish him a speedy recovery.)

He's not the only one. Science and science fiction have always inspired one another in turn, and Star Trek has inspired as much physics research as it has drawn upon over the decades. The most promising theory to date was advanced in 1994 by Mexican physicist Michael Alcubierre, who insisted that while relativity forbids faster than light travel when it comes to the fabric of space-time, regions of space also move relative to each other, and some of those regions could, theoretically, move faster than the speed of light.

Alcubierre's notion is that the Enterprise would be enclosed within a highly distorted bubble of space-time, which would shrink in whatever direction the ship was traveling from the front of the ship, and expand behind it. The bubble could then move faster than light. Here's Lawrence Krauss, physics professor and author of The Physics of Star Trek, explaining it all for you in plain English, with just a balloon and a magic marker as props:

Ah, but that's relying on classical relativity. Bring it down to the quantum level and things get quite a bit trickier. Stefano Finazzi of the International School for Advanced Studies in Trieste, Italy, has been working the problem with a few colleagues, and earlier this month posted a paper claiming that "Warp drives would become rapidly unstable once superluminal speeds are reached." Bummer. It's got something to do with "the renormalized stress-energy tensor" which the math shows grows exponentially at faster-than-light speeds, making that cozy little bubble housing the Enterprise dangerously unstable.

Oh, and the bubble would also be filled with Hawking radiation, most likely killing the entire crew. Kirk and Crew don't know how good they have it in their fictional film and TV world, where the laws of physics can be bent at the whims of the writers.

Photo: Visualization of a spaceship in a warp field. Source: Wikipedia (Public Domain).

Boys and Their Toys

December 20, 2008

A few weeks ago we bid farewell to the Mars Phoenix Lander as it succumbed to the frigid Martian winter, but the machine did not expire in vain. All of NASA's Mars-centric missions are telling us more every day about the Red Planet, and getting us one step closer to every space geek's (*cough* Dave Mosher *cough*) not-so-secret fantasy: an actual human settlement on Mars. Via io9, I stumbled across this nifty concept art of futuristic Martian condos by award-winning video game artist Dawid Michalczyk; I'm betting Dave M's got his down payment and mortgage application in place already, just so he can get in cheaply on the ground floor.

Michalczyk's imagery reminded me of a recent talk I heard by entrepreneur Elon Musk, who dreamed up a plan back in 2001 to land a miniature experimental greenhouse on Mars ("Mars Oasis") to test the viability of certain food crops in that environment. Both are bona fide visionaries, but where Michalczyk is creating other-worldly terrains and domiciles for future planetary pioneers in virtual space, Musk is trying to make that dream a reality -- first with Mars Oasis (now on hold), and then with Space Exploration Technologies Corporation (SpaceX), which is developing partially reusable space launch vehicles.

Frankly, if there were any justice in the world, Musk would be a household name by now, on a par with Thomas Edison, or that other great visionary, Nikola Tesla. This is a guy who taught himself computer programming as a kid in South Africa, selling his first commercial software -- a space game called Blaster -- at age 12. He dropped out of high school and moved to Canada and the US, eventually earning an undergraduate degree in economics at the University of Pennsylvania.

Musk flirted briefly with grad school, but the entrepreneurial streak just wouldn't be denied. He lasted all of two days in Stanford's high energy physics program before founding an online content publishing for news organizations in 1995 -- when blogs weren't even a blip on most people's radars. By 2001, he'd made a fortune by inventing PayPal, the handy alternative to using credit cards for Web-based transactions that most certainly played a significant role in the rise of online shopping over the past decade.

Nor was he content to simply rest on his laurels and rake in the profits. Musk is first and foremost an innovator, and he's got the start-up ventures to prove it. There's the high-profile Tesla Motors, focused on the production of the Tesla Roadster, a high-performance luxury electric car. (Musk drove one to the talk he gave in Venice. My beloved spouse is still drooling with envy, and even I must admit, it's a pretty hot car. Personally, I'd rather see the funds for the bailout of the Big Three automakers go to firms like Tesla Motors -- let's reward imagination and innovation, not complacency and incompetence.) He also founded Solar City, which manufactures solar photovoltaic panels.

And then there's Space-X, founded when Musk discovered that launch costs were prohibitively high to make his Mars Oasis project viable. In fact, it hampers his eventual long-term goal of making humanity "a truly space-faring civilization." The problem is that launch vehicles are only used once, and usually burn up in earth's atmosphere upon re-entry. "How many of you would have driven here today if you could only drive your car once?" he asked -- rhetorically. So SpaceX is developing space launch vehicles designed to be cheaper and reusable, thereby decreasing costs and increasing the reliability of going into space.

First off the launch pad was Falcon 1, which made its first successful flight on September 28, 2008. It's the first privately funded liquid-fueled rocket to reach orbit; you can see some nifty video footage, taken by cameras mounted on the spacecraft, here. And the company managed it with just 25 members of the launch crew and six more in mission control, at a small launch site in the Marshall Islands -- all part of Musk's master plan to keep costs down so space travel becomes commercially viable.

Next up is Falcon 9, slated for launch sometime next year. With NASA funding (at least for the unmanned phase of the project), the company is also designing an orbital vehicle called the SpaceX Dragon, a cargo rocket designed to dock with the International Space Station and deliver supplies and return experiments to Earth. Musk pointed out that the US space shuttle program will end in 2011. And then for several years there won't be a US space program; instead, we'll be paying the Russians a cool $70 million per year for seats for our astronauts aboard Russian space shuttles. Musk argues -- persuasively, in my opinion -- that it makes better financial sense to invest in companies like SpaceX rather than let our once-laudable space program founder.

More jaded observers might mistakenly conclude that the youthful Musk is all about fast cars, rocket ships, and other-worldly pipe dreams. But this is a man who combines the daring to dream big with the discipline and seriousness of purpose to actually get things done. He might not succeed in our lifetime in achieving truly commercial space travel, but he'll definitely push the boundaries of what's possible, and probably come up with some revolutionary breakthroughs along the way.

Photos: (top) Martian condos as envisioned by Dawid Michalczyk. Source: Eon Works. (bottom) The view from Falcon 1 (Flight 4) as it rockets into space. Source: SpaceX.

Beam Me Up

June 23, 2008

My favorite character in The X-Men series is Kurt, a.k.a., Nightcrawler, whose special mutant power is the ability to teleport, instantaneously moving from one location to another, even across vast distances. Needless to say, he gets around. The downside is his freakish appearance: blue-tinged skin covered in tattoos -- "one for every sin," he tells Halle Berry's Storm in X2: X-Men United -- with a spiked tail, yellow eyes, and taloned stumps for hands (not to mention that disturbingly reptilian tongue). Poor Kurt won't be winning any "Sexiest Superhero of the Year" contests anytime soon. But his shy, sweet nature resonated with me, as well as his child-like pride in his brief fifteen minutes of local fame. He, himself, is just Kurt, reviled freak of nature, "But in the Munich Circus, I was known as the Amazing Nightcrawler!"

I was reminded of Kurt last week when I stumbled upon a fascinating article, "Five Superpowers Science Will Give Us in Our Lifetime." Picking a dream superpower is actually a frequent topic of conversation in the Geekdom, and for the last several years, my choice has always been teleportation. Think about all the time we waste getting from Point A to Point B, with all the hassles and indignities suffered along the way, regardless of your choice of transport.

Now imagine getting there instantaneously. Poof! One minute you're in Los Angeles, the next you're at your best friend's wedding in the Bahamas. What could be better than that? (For fantasy purposes, it is assumed that one's clothing makes the trip as well. That still leaves the problem of luggage, but really, why haul stuff around when you can just pop back home to change in a nanosecond?)

Maybe that's why I often win such debates. Teleportation is a staple of science fiction for a reason, after all. From a scientific standpoint, it involves dematerializing an object at one point and sending the details of its precise atomic configuration to another location. This information can then be used to construct an exact replica of the original object out of new atoms, arranged in precisely the same pattern as the original.

Teleportation was noticeably absent from the above-cited article, perhaps because it is unlikely to be achieved for any practical purposes in our lifetimes. Physicists can teleport individual photons, and even whole laser beams ("telecloning"), but they are nowhere near being able to teleport a life-sized object. In fact, for a long time physicists assumed it wasn't even possible because the notion violates the Uncertainty Principle.

It's a classic catch-22. If we want to teleport an object, we have to scan it to get the precise information we need about its atomic structure. And I do mean "precise": as in, right down to the subatomic level. But uncertainty says that the more accurately an object is scanned, the more it is disturbed by the scanning process. We can't measure a subatomic particle without altering it in some way. So it's impossible to extract all the information we would need from an object in order to create an exact copy in another location via teleportation.

In 1993, an IBM physicist named Charles Bennett and his colleagues found a convenient loophole via entanglement (see this prior post for a brief recap of entanglement). Three particles are involved: A (the original particle to be teleported), and an entangled pair of particles (B and C) It's a bit like watching a street game of three-card monte. First, B and C are entangled and sent to separate locations. B then interacts with A, and A's information is transferred to B. Since B is still entangled with C, any information transferred to B is also automatically sent to C, without any need to send it across physical space-time. C essentially turns into A, in the new location.

Naturally, there's a catch. We can "outwit" uncertainty, but we can only do so once. The original object is invariably destroyed in the teleportation process, because when B scans A, the latter's properties are permanently altered by the interaction. A no longer exists. C is now the only particle in that original state. So when Nightcrawler pops out of one location and into another, according to our current understanding of physics, he is actually destroying his physical body and recreating it from entirely new atoms in the new location.

Hmmm. Suddenly teleportation doesn't seem quite so attractive. Maybe I'll take that commuter flight after all.

Okay, your turn: what would be your superpower of choice, and why? Bonus points if you can find some real-world science that might one day make it a reality.

Photo: Alex Cumming as Nightcrawler in X2: X-Men United. 20th Century Fox/Marvel Studios (via Wikipedia)

MapQuest for Mars

June 18, 2008

It's summer, time for the great American tradition of the family vacation road trip! When I was a kid, our entire family criss-crossed the country one summer, from Seattle to Maine, in an old Buick station wagon, stopping off at Yellowstone National Park, the Grand Canyon, and a few other landmarks along the way. But mostly, I recall the tedium of 8-hour drives, punctuated by arguments between me and my siblings: "Are we there yet?" "Mom, he keeps looking at me!" Even my parents had their share of arguments, usually while looking over a map in the gigantic atlas that weighed more than my baby sister. Because of course my father wouldn't dream of asking for directions (that's my mom's story and she's sticking to it).

These days, the standard big atlases of my youth are pretty much obsolete, thanks to online resources like MapQuest and GoogleMaps -- both of which I use regularly. But what's a plucky space explorer to do when trying to land a spaceship on Mars (or the moons of Jupiter) sometime in the distant future? Our current "maps" of the red planet leave a lot to be desired in terms of the minute details, especially changing variables like wind speed, atmospheric pressure, and temperature. Sure, our little space probes have done an outstanding job giving us a rough idea of Martian topography, but frankly, the resolution just isn't good enough yet. You don't want to confuse a big boulder with a small pebble -- not when you're trying to land a multi-million-dollar space craft.

What we need is a 3D "super road map" giving us location-specific, detailed information about changing planetary surfaces and conditions. If only we had an imaging technique capable of producing such a map! Lucky for our future astronauts, scientists at the Rochester Institute of Technology (RIT) in upstate New York are developing such an imaging system based on LIDAR (Light Detection and Ranging), in collaboration with MIT's Lincoln Laboratory.

LIDAR is very similar to radar in concept, except it uses laser light instead of radio waves to determine distances, by measuring the time it takes for light to travel from a laser beam to an object and then back again. Not only could such a system prove invaluable for mapping out the surface of the moon, Mars, or other planetary surfaces and atmosphere, it can also probe the environments of comets or asteroids. The RIT scientists will test their prototype system under conditions that mimic those likely to be encountered during NASA space missions.

Improved resolution is the key. Generally speaking, we can usually only image objects roughly the same size as the wavelength of light being used, or larger. The radio waves used in radar, for instance, are terrific at detecting metallic objects, but rocks, or even raindrops, might not produce much in the way of detectable reflections, so these sorts of things would be pretty much invisible to radar. LIDAR uses much shorter wavelengths (eg, in the optical and ultraviolet regimes of the electromagnetic spectrum), and thus the system can detect very small objects, even tiny particles in the atmosphere. In fact, LIDAR is already being used to study atmospheric conditions here on Earth.

Lasers also have a very narrow, focused beam, so LIDAR enables the mapping of physical features with much higher resolution than conventional radar. Its "footprint" can be less than one meter, making it possible to map the floor underneath a thick forest canopy in the Amazon, or details in narrow urban canyons obscured by tall buildings. Such systems were used in the aftermath of the terrorist attacks on September 11, 2001, to map out the debris from the collapsed World Trade Center at Ground Zero in New York City. The resulting detailed topographical "maps" helped rescue workers navigate the often treacherous terrain by identifying unstable areas likely to shift or collapse. The maps also showed the locations of foundation-support structures, elevator shafts and so forth. (You can read more about LIDAR and its many terrestrial applications here.)

According to RIT scientist Donald Figer, his team's LIDAR imaging detector will be able to distinguish topographical details of a planetary surface that differ in height by as little as 1 centimeter. And its imaging system will be able to swiftly capture wide swaths of entire scenes as the laser beams sweep across the terrain. Current LIDAR systems use a single pixel, which must be moved across a scene bit by bit to slowly build up an image. Accuracy is important in space navigation, but so is speed: you've got to be able to adapt to changing conditions quickly, after all. That's why Figer believes his team's LIDAR system could become "a workhorse for a wide range of NASA missions" -- thereby sparing our future astronauts the embarrassment of having to ask local planetary inhabitants for directions.

Photo: LIDAR image of Ground Zero in New York City, September 27, 2001. NOAA/U.S. Army JPSD