I’m sure you’ve seen the headlines. In case you’ve been hiding under a rock for the last few weeks, or at least tuning out the news (understandable, given that this is election season), here is a sampling:
- Star Trek’s faster-than-light travel possible: NASA scientist | Business Standard
- NASA Scientist Developing Star Trek ‘Warp Drive’ « CBS Houston
- ‘Warp drive’ may be more feasible than thought, scientists say | Fox News
- Nasa physicist says warp drive is more feasible than thought (Wired UK)
- Warp Drives Might Be More Realistic Than Thought | Wired Science | Wired.com
- Star Trek’s faster-than-light travel possible: NASA scientist | Business Standard
- NASA: Warp drive is ‘plausible and worth further investigation’ | DVICE
- NASA Starts Work on Real Life Star Trek Warp Drive
- Warp drive at NASA « The Gauge Connection
- Scientists ponder interstellar travel at NASA-backed space summit | The Raw Story
But it all traces back to this article:
The media frenzy was triggered by comments made by physicist Dr. Harold “Sonny” White of the Eagleworks Lab at NASA’s Johnson Space Center at the 100 Year Starship 2012 Symposium, held September 13-16, 2012 in Houston. The event, branded with the theme “Transition to Transformation … The Journey Begins,” featured numerous guest speakers, mostly scientists, but also including Star Trek actors Levar Burton and Nichelle Nichols (who has a long and successful history of working with NASA on initiatives to recruit women and minorities into science and technology fields).
(This is the second such symposium. The first was held in Orlando in October of last year.)
Backed by the Dorothy Jemison Foundation for Excellence, the Foundation for Enterprise Development, Icarus Interstellar, and grants from DARPA and NASA, the 100 Year Starship Initiative is a non-government entity founded in January of this year with the goal of persuing and encouraging public and private initiatives to make interstellar space flight achievable within a century.
So, what did Dr. White say at this symposium to create such buzz?
“There is hope.”
Well, he said a bit more than that, but explaining requires a bit of back story.
In the Beginning, there was Alcubierre
For many decades, the bending of space-time has been a conceit long favored by science fiction writers as a workaround for dealing with the daunting (and, literally, astronomical) distances involved in interstellar space flight. But, within the scientific community itself, the idea of “warp drive” had been mainly a topic of idle speculation, with few scientists finding the prospect realistic as a practical means of spacecraft propulsion.
Then, in 1994, Mexican theoretical physicist Miguel Alcubierre published a paper 1 outlining what has come to be known as the Alcubierre drive, the first example of a physicist earnestly tackling the mathematical heavy lifting of exploring the concept in depth. In the paper, Alcubierre defined a space-time metric (and its associated stress-energy tensor) in which space in front of the ship is contracted, and the space behind the ship is expanded. These contracting and expanding regions of space-time propagate as waves, with the spacecraft riding along in a flat region inside this warp bubble, not moving with respect to the space in which it sits, and thus experiencing no inertial effects.
What makes this conceptually possible is that at no point is the spacecraft itself moving faster than light with respect to the space-time manifold in which it is embedded. Such superluminal motion is of course forbidden by relativity. However, relativity does not forbid space-time itself from expanding or contracting faster than lightspeed. In fact, an important component of modern cosmology is the concept of “inflation,” a brief period during the beginning moments of the universe in which space-time expanded at a superluminal rate.
But, as intriguing as this is, there are problems with Alcubierre’s idea. First of all, while Alcubierre showed that it is indeed theoretically possible for such a warp bubble to exist, we still have no idea how to generate one. Krasnikov and Coule2,3 have argued that constructing such a field would require constructing the fields in motion such they are already moving at superluminal velocities. In other words, creating a warp drive requires the existence of a warp drive.
In 2002, a paper appeared4 arguing that it would be impossible for the crew of a ship utilizing an Alcubierre drive to send signals to the front of the warp bubble, rendering it impossible for them to steer or stop the ship. A 2009 paper5 suggested that the crew of such a ship would be subjected to intense amounts of Hawking radiation; although, in this context, it might be more accurate to refer to it as Unruh radiation.
But, perhaps the biggest obstacle was one of energy. This problem was two-fold. One was a requirement for the creation of a region of intense negative energy density, a feat which would require the existence of some form of exotic matter with properties which, while not forbidden by the laws of physics, is not known to exist. The other aspect of the problem was one of magnitude. Pfenning and Ford6 estimated that the energy equivalent of -1064 kg would be needed, a magnitude greater than the estimated mass of the known universe. Furthermore, it was argued in the same paper that the exotic matter ring required to establish the needed negative energy density geometry would have to be an impossibly thin structure.
In a 1999 paper7, Chris Van Den Broeck tackled the issue of how much energy would be required to produce a warp bubble. By modifying the geometry of the bubble, he came up with a configuration which reduced the energy needed to transport a handful of atoms to roughly three solar masses. Krasnikov8,9 then built upon this work to reduce the energy requirements to just a few milligrams. (Remember, this is for generating a warp bubble containing just a TINY amount of matter.)
Dr. White’s Findings
A paper has yet to be published (or even pre-printed on arXiv.org) outlining Dr. White’s latest work, but in his presentation at the 100YSS conference, he revealed that his calculations show that by replacing the flat ring of exotic material with more of a toroidal shape, the energy requirements for a 10m warp bubble traveling at 10c would be reduced from the equivalent energy bound up in the mass of Jupiter to that of a mass of 500 kg. On top of that, he claimed that his calculations show that causing the intensity of the space warp to oscillate reduces the energy requirement even more.
“The math would allow you to go to Alpha Centauri in two weeks as measured by clocks here on Earth,” White said. “So somebody’s clock onboard the spacecraft has the same rate of time as somebody in mission control here in Houston might have. There are no tidal forces, no undue issues, and the proper acceleration is zero. When you turn the field on, everybody doesn’t go slamming against the bulkhead, (which) would be a very short and sad trip.”
“The findings I presented today change it from impractical to plausible and worth further investigation,” he told SPACE.com. “The additional energy reduction realized by oscillating the bubble intensity is an interesting conjecture that we will enjoy looking at in the lab.”
The lab? Yes, the lab. Dr. White has devised an apparatus to test this concept on a table-top scale at Johnson Space Center. Known as the White-Juday Warp Field Interferometer, this experiment is designed to look for perturbations in space-time on a scale of one part in 10 million. Not enough to propel a space craft, but enough to provide a proof of concept. If it works.
“Although this is just a tiny instance of the phenomena, it will be existence proof for the idea of perturbing space time-a “Chicago pile” moment, as it were. Recall that December of 1942 saw the first demonstration of a controlled nuclear reaction that generated a whopping half watt. This existence proof was followed by the activation of a ~ four megawatt reactor in November of 1943. Existence proof for the practical application of a scientific idea can be a tipping point for technology development.”
Somewhat similar to the Michelson-Morley experiment used to disprove the existence of the luminiferous æther in the late 19th century, the device can also be thought of as a scaled-down version of the interferometer experiments currently being used in attempts to detect gravitational waves, a phenomenon predicted by general relativity. The primary difference with the White-Juday Warp Field Interferometer is that one arm of the light path passes through a 1 cm diameter toroidal capacitor ring.
Of course, this ring will generate a region of positive energy density, not a region of negative energy density as needed by the Alcubierre drive concept. Nevertheless, if it works, it would be a splendid proof of the ability to manipulate space-time in an energy-efficient manner. And if anyone happens to have a few tons of negative energy density unobtainium on hand, I’m sure that Dr. White and his team would love to hear from them.
- Alcubierre, Miguel (1994). “The warp drive: hyper-fast travel within general relativity”. Classical and Quantum Gravity 11 (5): L73–L77. arXiv:gr-qc/0009013. Bibcode: 1994CQGra..11L..73A. doi:10.1088/0264-9381/11/5/001
- S. Krasnikov (1998). “Hyper-fast travel in general relativity”. Physical Review D 57 (8): 4760. arXiv:gr-qc/9511068. Bibcode: 1998PhRvD..57.4760K. doi:10.1103/PhysRevD.57.4760.
- Coule, D H (1998). “No warp drive”. Classical and Quantum Gravity 15 (8): 2523–2537. Bibcode: 1998CQGra..15.2523C. doi:10.1088/0264-9381/15/8/026.
- Natário, José (2002). “Warp drive with zero expansion”. Classical and Quantum Gravity 19 (6): 1157–1165. arXiv: gr-qc/0110086. Bibcode: 2002CQGra..19.1157N. doi: 10.1088/0264-9381/19/6/308.
- Finazzi, Stefano; Liberati, Stefano; Barceló, Carlos (2009). “Semiclassical instability of dynamical warp drives”. Physical Review D 79 (12): 124017.arXiv: 0904.0141. Bibcode: 2009PhRvD..79l4017F. doi: 10.1103/PhysRevD.79.124017.
- Pfenning, Michael J.; Ford, L. H. (1997). “The unphysical nature of ‘Warp Drive'”. Classical and Quantum Gravity 14 (7): 1743–1751. arXiv: gr-qc/9702026. Bibcode: 1997CQGra..14.1743P. doi: 10.1088/0264-9381/14/7/011.
- Broeck, Chris Van Den (1999). “A ‘warp drive’ with more reasonable total energy requirements”. Classical and Quantum Gravity 16 (12): 3973–3979. arXiv: gr-qc/9905084. Bibcode: 1999CQGra..16.3973V. doi: 10.1088/0264-9381/16/12/314.
- S. Krasnikov (2003). “The quantum inequalities do not forbid spacetime shortcuts”. Physical Review D 67 (10): 104013. arXiv: gr-qc/0207057. Bibcode: 2003PhRvD..67j4013K. doi: 10.1103/PhysRevD.67.104013.
- van den Broeck, Christopher “Alcubierre’s warp drive: Problems and prospects”. AIP Conference Proceedings 504: 1105-1110. 2000. Bibcode: 2000AIPC..504.1105V. doi: 10.1063/1.1290913.
For more information:
- Paul Karl Hoiland, “Towards a more realistic Gravitomagnetic Displacement Drive”. vixra.org/pdf/1111.0044v1.pdf
- White, Harold, “Warp Field Mechanics 101”, ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20110015936_2011016932.pdf
- White, Harold; March, Paul; Williams, Nehemiah; O’Neill, William, “Eagleworks Laboratories: Advanced Propulsion Physics Research” NASA Technical Reports Server – Eagleworks Laboratories: Advanced Propulsion Physics Research
- NASA Technical Reports Server – Advanced propulsion concepts
- Daydreaming Beyond the Solar System with Warp Field Mechanics | Icarus Interstellar
- The Schwarzchild Warp Drive
- NASA – Advanced Space Transportation Program fact sheet
- Propulsion research goes into hyperdrive – Technology & science – Space – Space.com | NBC News
- NASA Technical Reports Server – An overview of the NASA Advanced Propulsion Concepts program
- NASA – Warp Drive, When?
- NASA – Emerging Possibilities for Space Propulsion Breakthroughs
- NASA – Some Emerging Possibilities
- Breakthrough Propulsion Physics