Saturday, February 13, 2010
The "Dyson Sphere"
At any given moment an episode of the multiform Star Trek is on some television channel. I once thought that of the entire series that Star Trek: Next Generation was the number one place holder followed by the original Star Trek. Now I am not so sure for one of the local television stations has been airing my favorite series. As with the original and all the spin offs, I am annoyed with the creative talents of the engineering section that can spout a ton of incomprehensible physics and resolve a threatening issue but I am impressed when the plots revolve around some ethical issues and human and alien characteristics...and the android Data. For some reason, Star Trek: The Next Generation has lost much of its luster not in the graphics but in the stereotypical representations of the cast. The only solace lies within Data. All of the above is slightly off the topic. Last night's episode revived a character from the original series--Montgomery Scott [James Doohan] ["Scotty"]...head of engineering. The plot is thin and not really enjoyable. But what was interesting was the introduction of a concept proposed by Freeman Dyson...the "Dyson Sphere".
Plot for episode 130 [Season 6, Episode 4] ["Relics"] of Star Trek: The Next Generation
The USS Enterprise-D, responding to a distress call, drops out of warp to discover a nearby Dyson sphere. They trace the distress call to the USS Jenolen, a Federation transport ship that has been reported missing for 75 years, and which has crashed intact on the sphere's outer hull. Riker, La Forge and Worf transport to the Jenolen while the Enterprise investigates the sphere. La Forge discovers that the Jenolen's transporter has been jury rigged to sustain two life signals within its pattern buffer indefinitely, though one has degraded too far to be recovered. La Forge reverses the process and restores the remaining life form, which turns out to be former Starfleet officer Captain Montgomery Scott.
Scott explains during a check up of his health aboard the Enterprise that he was only a passenger aboard the Jenolen during his retirement, but when the ship was caught in the Dyson sphere's gravity field, only he and one other officer survived the crash, and Scott had rigged the transporter to try to keep them "alive" while help came. After being cleared by Dr. Crusher, Scott is eager to see the advances in technology including a tour of the Engineering deck, but quickly finds that his old knowledge has long been surpassed and his efforts to help are instead getting in the way of normal operations. Ordered to leave Engineering by La Forge, Scott heads to Ten Forward, and is upset to learn that alcohol is no longer served on Starfleet ships. Data offers a potent beverage from Guinan's private stock to Scott, which Data can only describe as being "green". With the bottle in hand, Scott uses one of the Enterprise's holodecks to recreate the bridge of his old ship, the Enterprise, to try to relive his past. Captain Picard joins Scott after hearing of his difficulties in becoming adjusted to the 24th century and tries to counsel him, to which Scott declares himself a relic of the past.
The next day, in continuing the survey of the Dyson sphere, Picard suggests to La Forge to enlist Scott's help to recover existing survey data from the older Jenolen systems, technology at which Scott is adept. The two return to the Jenolen and begin to recover its memory core with Scott's help. The Enterprise discovers a port on the side of the Dyson sphere, but when they try to communicate with the systems, the ship is pulled into the Dyson sphere by automated controls which temporarily disables their systems. Though they are able to recover control before the ship impacts with the star inside the sphere, they find the star is unstable and emitting large amounts of radiation which will be lethal to the crew, and surmise that the sphere was long abandoned by its creators due to this. The Enterprise quickly realizes the only exit from the interior of the sphere is the port they used but cannot figure out how to open it from this side. When La Forge tries to make contact with the Enterprise, he discovers it missing, and works with Scott to make the Jenolen flight-worthy. They discover the same port the Enterprise found and surmise the Enterprise is trapped inside. La Forge and Scott manage to open the port without being pulled in and then wedge the Jenolen in the open port, using its shields to keep it open while the Enterprise escapes, rescuing the two engineers from the Jenolen just before destroying it with photon torpedoes.
As the Enterprise returns to its mission, the crew of the ship give Scott his very own shuttlecraft "on extended loan" to either continue to his retirement or to explore the galaxy. Scott thanks the crew and reminds La Forge to make the most of his time as the Chief Engineer of the Enterprise before he departs.
Now, physicist Freeman Dyson postulated a sphere could be built around a star with inhabitants living on its interior wall. I am not convinced that this is nothing more than science fiction and a desire to discover alien life forms.
The Dyson sphere is a hypothetical structure of immense size. It is a sphere that completely (or almost completely) encloses a star, making use of all the energy radiated away by the fusion reactions taking place in its core. The idea of a Dyson sphere was first formalized and popularized by renowned physicist Freeman Dyson in an 1959 article in Science entitled "Search for Artificial Stellar Sources of Infra-Red Radiation," though he originally got the idea from a 1945 science fiction novel by Olaf Stapledon entitled Star Maker.
Our sun has an energy output of around 4 x 10^26 watts, or approximately 100 million times humanity's total energy consumption throughout the past century every second. If this energy could be harnessed via a Dyson sphere, we would have enough power to sustain a population trillions of times our current population for many eons.
The original proposal for a Dyson sphere was not for a solid sphere, but a collection of ~10^5 objects which collectively absorb the bulk of the star's solar energy. Sometimes called a "Dyson swarm," this would allow the incremental construction of the system, with subcomponents orbiting the star independently. From the outside, such a swarm would appear black, emitting only infrared radiation. Some of our orbiting infrared telescopes have been searching for such bodies as Dyson spheres or swarms for decades, with no luck. If reflectors were used on the interior of the objects, the radiant energy might be directed only one way, making it hard to detect from a distance.
Preliminary calculations have shown that our solar system contains enough rigid matter to construct a Dyson swarm, but probably not a rigid Dyson sphere, which would have to be about a million km (600,000 miles) thick to be stable. A good candidate building material would be buckminsterfullerene, an allotrope of carbon with immense strength.
The Dyson sphere is often mentioned in conjunction with the Kardashev classification scheme, a method used to classify hypothetical civilizations by way of their energy sources. According to this classification scheme, a Type I civilization would be one which utilizes the power sources of an entire planet, a Type II civilization would be one that uses an entire star's output for power, and a Type III civilization would be that which uses an entire galaxy for power. A more speculative Type IV civilization would be one which harnesses the power of an entire universe. The construction of a Dyson sphere would place a civilization squarely in the Type II category.