Black hole starship: Difference between revisions

AIn [[astronautics]], a '''black hole starship''' is athe theoretical ideaconcept forof enablinga [[interstellar travelstarship]] bycapable of [[spacecraftinterstellar propulsion|propellingtravel]] a [[starship]] by using a [[black hole]] as thean energy source for [[spacecraft propulsion]]. The concept was first discussed in science fiction, notably in the book ''[[Imperial Earth]]'' by [[Arthur C. Clarke]], and in the work of [[Charles Sheffield]], in which energy extracted from a [[Rotating black hole|Kerr-NewmanKerr–Newman black hole]] is described as powering the rocket engines in the story "Killing Vector" (1978).<ref>Sheffield, Charles, "Killing Vector," [[Galaxy Science Fiction|Galaxy Magazine]], March 1978</ref>

In a more detailed analysis, a proposal to create an [[artificial black hole]] and using a [[parabolic reflector]] to reflect its [[Hawking radiation]] was discussed in 2009 by Louis Crane and Shawn Westmoreland.<ref name="cranewestmoreland2009">Louis Crane and Shawn Westmoreland, "[https://arxiv.org/abs/0908.1803 Are Black Hole Starships Possible]" (ArXiv preprint 12 Aug 2009). Retrieved 7 April 2017.</ref> Their conclusion was that it was on the edge of possibility, but that [[quantum gravity]] effects that are presently unknown will either make it easier, or make it impossible.<ref>{{Cite journal |url=https://www.newscientist.com/article/mg20427361.000-dark-power-grand-designs-for-interstellar-travel.html |title=Dark power: Grand designs for interstellar travel |journal=New Scientist |date=25 November 2009 |issue=2736 |last=Chown |first=Marcus}} {{subscription required}}</ref> Similar concepts were also sketched out by [[Alexander Bolonkin]].<ref>Alexander Bolonkin, Alexander, ''Life. Science. Future,'' lulu.com, 2011, pp. 198-199.</ref>

Black holes seem to have a sweet spot in terms of size, power and lifespan which is almost ideal. A black hole weighing 606,000 metric tons (6.06 × 10⁸ kg), or roughly the mass of the ''[[Seawise Giant]]'' (the longest sea-going ship ever built) would have a [[Schwarzschild radius]] of 0.9 [[Metre#SI prefixed forms of metre|attometers]] (0.9 × 10^&ndash;18 m, or 9 × 10^&ndash;19 m), a power output of 160 [[Watt#Petawatt|petawatts]] (160 × 10¹⁵ W, or 1.6 × 10¹⁷ W), and a 3.5-year lifespan. With such a power output, the black hole could accelerate to 10% the speed of light in 20 days, assuming 100% conversion of energy into kinetic energy. Assuming only 10% conversion into kinetic energy, it would only take 10 times longer to accelerate to 0.1''c'' (10% of the [[speed of light]])more.<ref name="cranewestmoreland2009" />

Getting the black hole to act as a power source and engine also requires a way to convert the Hawking radiation into energy and thrust. One potential method involves placing the hole at the focal point of a parabolic reflector attached to the ship, creating forward thrust, if such a reflector can be built. A slightly easier, but less efficient method would involve simply absorbing all the gamma radiation heading towards the fore of the ship to push it onwards, and let the rest shoot out the back.<ref name="io9_2009">Tim Barribeau, [http://io9.com/5391989/a-black-hole-engine-that-could-power-spaceships "A Black Hole Engine That Could Power Spaceships"], io9, Nov. 4, 2009</ref><ref name="io9_2014">Jeff Lee [http://io9.gizmodo.com/how-to-power-a-starship-with-an-artificial-black-hole-1502929100 "How to power a starship with an artificial black hole"], io9, Jan. 6, 2014 (retrieved 7 April 2017)</ref> This would, however, generate an enormous amount of heat as radiation is absorbed by the dish.

{{cite journal |last=Page |first=Don N. |authorlinkauthor-link=Don Page (physicist) |date=1976 |title=Particle emission rates from a black hole: Massless particles from an uncharged, nonrotating hole |journal=Physical Review D |volume=13

|issue=2 |pages=198–206 |doi=10.1103/PhysRevD.13.198 |url= |accessdate= |bibcode = 1976PhRvD..13..198P }}

</ref><ref name="acceleration">{{cite journal|last1=Lee|first1=Jeffrey S.|title=Acceleration of a Schwarzschild Kugelblitz Starship|journal=[[Journal of the British Interplanetary Society]]|date=March–April 2015|volume=68|pages=105–116|bibcode=2015JBIS...68..105L |url=https://www.researchgate.net/publication/293633217_Acceleration_of_a_Schwarzschild_Kugelblitz_Starship293633217}}</ref> In the [[Journal of the British Interplanetary Society]], Jeffrey S. Lee of [[Icarus Interstellar]] states a typical quantum of radiation from a one-attometer black hole would be too energetic to be reflected. Lee further argues absorption (for example, by [[pair production]] from emitted gamma rays) may also be infeasible: A titanium "Dyson cap", optimized at 1&nbsp;cm thickness and a radius around 33&nbsp;km (to avoid melting), would absorb almost half the incident energy, but the maximum spaceship velocity over the black hole lifetime would be less than 0.0001''c'' (about 30 km/s), according to Lee's calculations.<ref name="acceleration" />

Govind Menon of [[Troy University]] suggests exploring the use of a rotating (Kerr-NewmannKerr–Newmann) black hole instead: "With non-rotating black holes, this is a very difficult thing...we typically look for energy almost exclusively from rotating black holes. Schwarzschild black holes do not radiate in an astrophysical, gamma ray burst point of view. It is not clear if [[Hawking radiation]] alone can power starships."<ref name="io9_2009" />

* [[Arthur C. Clarke]], ''[[Imperial Earth]]'' (1976)

* [[Charles Sheffield]], "Killing Vector" (1978)